soil evaluation and risk assessment -...

Soil Evaluation and Risk Assessment

Sites: 85 South, 85 North, 133, and 112 Fort Greely, Alaska

Revision 1 December 06, 2002

United States Army Corps of Engineers

Alaska District PO Box 6898 Anchorage, AK 99506-0898

Soil Evaluation and Risk Assessment Page 1 of 128, 12/18/02 Fort Greely BRAC Sites 85 South, 85 North, 133, and 112,

EXECUTIVE SUMMARY The U.S. Army Engineer District (USAED) Alaska has conducted an environmental evaluation to address four sites under the Fort Greely Base Realignment and Closure (BRAC) program. These sites are designated:

• Site 85 South; • Site 85 North; • Site 133; and • Site 112.

Surface and subsurface soils were sampled at each site during various events from 1991 through 1998. Data were compared against Alaska Department of Environmental Conservation (ADEC) Method Two cleanup levels. The data were then evaluated with ADEC Method Three risk evaluation procedures. ADEC Method Four risk assessment procedures were used for Site 85 North.

Based on the results of the evaluation, no further active remedial action is recommended for these four sites. Implementation of institutional controls is recommended. Institutional controls should provide for industrial/commercial land use, as well as other specific needs as described in the site-specific sections of this report. Biovent wells at Sites 85 South and 85 North should be decommissioned.

Based on an industrial/commercial scenario for future land use, the cumulative risks for each site are as follows.

Site 85 South Calculations resulted in a cumulative industrial cancer risk of 8.9x10-6 and non-cancer industrial hazard index of 0.76.

Site 85 North The current (baseline) human health risk on site is conservatively calculated as 1.1x10-7 for excess lifetime cancer risk (ELCR) and 0.00 for hazard index. These figures are orders of magnitude below the ADEC targets. The recommended alternative cleanup levels (ACLs) would yield a cumulative ELCR of 7.3x10-7 and a hazard index of 0.01. This is over an order of magnitude less than the ADEC target of 1x10-5.

Site 133 Calculations resulted in a cumulative industrial cancer risk of 1.3x10-5 and non-cancer industrial hazard index of 0.19.

Site 112 Calculations resulted in a cumulative industrial cancer risk of 7.4x10-6 and non-cancer industrial hazard index of 0.085.

Background and Methods Sites 85 South, 85 North, and 133 are associated with historical fire training practices on base, and have a history of site investigation extending back to the 1980’s. Site 112 is a formerly fenced salvage area that was investigated during the BRAC program.


This evaluation was initially designed to proceed in general accordance with United States Environmental Projection Agency (EPA) soil screening guidance. Detected analytes were to be compared to EPA Region 9 Preliminary Remediation Goals (PRGs) and Region 3 Risk Based Concentrations (RBCs). The study now presents ADEC cleanup criteria and methodologies.

Another modification took place during the evaluation process. Under the BRAC program, Sites 85 South, 133, and 112 were slated as surplus properties with the intent of future property transfer in mind. Site 85 North was to be retained by DOD. With potential property transfer in mind, the properties were initially evaluated against residential criteria in addition to industrial/commercial criteria. However, recent changes have occurred in the BRAC program. The subject sites are no longer slated for potential property transfer under the BRAC program; they are to be retained in DOD inventory. Consequently, this report presents evaluation under the industrial/commercial scenario. The industrial/commercial scenario is used because of the locations (e.g. proximity to airfield), historical uses, and expected future uses of the sites. Residential risk calculations are presented in Appendix D.

During the evaluation process, concerns were raised about detection limits for older data regarding how they compare to current applicable regulatory criteria. As a result, data were reviewed to identify valid values to be used in the evaluation and address detection limit concerns. Valid data sets were compared to ADEC Method Two criteria as provided in 18 AAC 75.341, Tables B1 and B2. Compounds of potential concerns (COPCs) with concentrations that exceeded any one of the three cleanup levels for the inhalation, ingestion, or migration to groundwater pathways were identified.

Leachability modeling was conducted to evaluate the migration to groundwater exposure pathway for selected analytes that exceeded the ADEC Method Two criteria and the site specific levels calculated using the soil screening equations under Method Three.

Initial evaluation of Site 85 North under ADEC Method Three indicated a cumulative risk greater than 1x10-5. Therefore, Site 85 North was evaluated further using a Method Four risk assessment to allow for more accurate and site-specific input conditions. The evaluation of Site 85 North is considered a “streamlined” risk assessment. Due to the uncomplicated nature of the site and the small area involved, a simplified version of the risk assessment as outlined in ADEC’s “Risk Assessment Procedures Manual” is warranted. This streamlined assessment uses many of the standard default input parameters that are found in ADEC 1999, EPA 2000, and EPA 1996. The site risks are calculated using the equations found in EPA 2000 and ADEC 1999 modified to yield the site risk.

Site 85 South

Detected DRO concentrations exceed the ADEC Method Three calculated ACLs for the migration to groundwater pathway. In total, only three separate analyses for DRO exceeded the ACL. The highest detected value of DRO was 4800 mg/kg, 1500 mg/kg over the calculated ACL of 3300 mg/kg. However, leachability modeling indicated that these DRO exceedances would not impact groundwater.

Site 85 North

Existing contamination at Site 85 North exceeds the ADEC Residential Cleanup Levels (Method 2) for DRO, benzene, tetrachloroethylene, DDD, DDT, and Dieldrin. Except for DDD and DDT, all exceedances are only for the migration to groundwater pathway (DDD and DDT exceed both


the migration to groundwater pathway and incidental ingestion pathway). Leachability modeling conducted for other sites at Fort Greely has demonstrated that the migration to groundwater pathway is not a completed pathway for the contaminants on site.

A soil cap has been placed over Site 85 North subsequent to conducting the risk assessment. The soil cap provides additional protection against exposure, and additional assurance that input used in the risk assessment is adequately conservative.

ACLs are proposed that are at or below the more conservative residential cleanup levels for the ingestion and inhalation pathways for all contaminants except DDD, DDE, and DDT. The proposed ACLs for these three pesticides are above the conservative residential cleanup levels. The risk assessment shows that for the current industrial scenario, all cumulative risks are below the ADEC targets.

Site 133

Methylene chloride, DRO and 1,2 dibromoethane exceeded the Method Three calculated ACLs for the migration to groundwater pathway. Two results of methylene chloride (0.1 mg/kg and 0.2 mg/kg) exceeded the ACL of 0.0525 mg/kg; two DRO results (5400 and 4300 mg/kg) exceeded the ACL of 3300 mg/kg; and one result of 1,2 dibromoethane (0.03 mg/kg) exceeded the calculated level for migration to groundwater of 0.00056 mg/kg.

The leaching model directly illustrated that neither DRO nor methylene chloride would impact groundwater at levels exceeding ADEC cleanup criteria. By comparison of chemical parameters, it was also concluded that 1,2 dibromoethane would not be expected to adversely impact groundwater.

Site 112

Methylene chloride (9 of 23 results) was detected at Site 112 at levels that exceed the calculated Method Three ACL for the migration to groundwater pathway. All of the detections were estimations (J flagged). The highest estimated value was 0.24J mg/kg. The ACL for methylene chloride is 0.0525 mg/kg.

The estimated benzene value (0.14 mg/kg) was also carried through the entire evaluation process. This value, which is one-half of the highest detection level of a non-detect result, exceeded the calculated ACL for the migration to groundwater pathway by 0.026 mg/kg.

The leachability modeling supports that methylene chloride will not impact the groundwater at levels exceeding ADEC cleanup criteria. By comparing chemical parameters of benzene to methylene chloride, and by comparing site specific conditions to leachability modeling input from another Fort Greely site (Site 73), it is concluded that benzene would not impact groundwater at a level exceeding ADEC cleanup criteria.


TABLE OF CONTENTS EXECUTIVE SUMMARY ………………………………………………………………………1

ACRONYMS AND ABBREVIATIONS......................................................................................10

1.0 INTRODUCTION................................................................................................................13 1.1 Audience ............................................................................................................................13 1.2 Purpose...............................................................................................................................13 1.3 Structure of Document.......................................................................................................13

2.0 BACKGROUND..................................................................................................................15

3.0 GENERALIZED FORT GREELY PHYSICAL CHARACTERISTICS ............................16 3.1 Location .............................................................................................................................16 3.2 Regional Geology ..............................................................................................................16 3.3 Soils - Fort Greely Cantonment Area ................................................................................16 3.4 Surface Water Hydrology ..................................................................................................17 3.5 Hydrogeology ....................................................................................................................17

4.0 CONDITIONS SPECIFIC TO THE FORT GREELY CANTONMENT AREA ...............19 4.1 Aquifer Thickness – Fort Greely Cantonment Area ..........................................................19 4.2 Hydraulic Gradient – Fort Greely Cantonment Area.........................................................20 4.3 Hydraulic Conductivity – Fort Greely Cantonment Area..................................................20 4.4 Fraction Organic Carbon in Soil – Fort Greely Cantonment Area ....................................21 4.5 Soil Moisture Content ........................................................................................................21

5.0 PROJECT APPROACH AND TASKS ...............................................................................22 5.1 Project Approach ...............................................................................................................22

5.1.1 Initial Approach ........................................................................................................ 22 5.1.2 Current Approach...................................................................................................... 22

5.2 Data Assembly and Review...............................................................................................23 5.3 Soil Evaluation and Risk Assessment................................................................................23

5.3.1 Screening With ADEC Method Two Cleanup Levels.............................................. 23 5.3.2 ACLs determined by the ADEC Method Three Calculator...................................... 23 5.3.3 Cumulative Risk determined by the ADEC Method Three Calculator .................... 24 5.3.4 Leachability Modeling .............................................................................................. 24 5.3.5 ADEC Method Four Analysis Site 85 North ............................................................ 25

5.4 Report Preparation .............................................................................................................25

6.0 SITE 85 SOUTH ..................................................................................................................26 6.1 Site Location and Background – Site 85 South .................................................................26 6.2 Identified Documentation and Past Site Activity– Site 85 South ......................................27

6.2.1 Pre-BRAC Investigation Activities........................................................................... 28 6.2.2 1997 Investigation Activities .................................................................................... 28 6.2.3 1998 Investigation Activities .................................................................................... 28 6.2.4 1999 Investigation Activities .................................................................................... 29

6.3 Potential Contaminants ......................................................................................................29 6.4 Synopsis of Contaminant Distribution – Site 85 South .....................................................29

6.4.1 Pre-Remedial Action................................................................................................. 29 6.4.2 Late and Post Remedial Action................................................................................. 30


6.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 85 South .....30 6.5.1 Contamination Source(s) .......................................................................................... 30 6.5.2 Release Mechanism(s) .............................................................................................. 31 6.5.3 Migration Pathways .................................................................................................. 31 6.5.4 Exposure Routes ....................................................................................................... 31 6.5.5 Potential Receptors ................................................................................................... 32

6.6 Data Set..............................................................................................................................32 6.6.1 Data Sources ............................................................................................................. 32 6.6.2 Review of Data Set Detection Limits ....................................................................... 33

6.7 ADEC Method Two Criteria..............................................................................................35 6.7.1 Initial Screening Process........................................................................................... 35 6.7.2 Elimination of Analytes ............................................................................................ 35 6.7.3 Findings of Initial Screening..................................................................................... 36

6.8 Alternative Cleanup Levels................................................................................................36 6.9 Cumulative Risk.................................................................................................................37 6.10 Leachability Modeling ...................................................................................................37 6.11 Complete Exposure Pathways........................................................................................37 6.12 Recommendations – Site 85 South ................................................................................38

7.0 SITE 85 NORTH..................................................................................................................39 7.1 Introduction........................................................................................................................39

7.1.1 Site Description......................................................................................................... 39 7.1.2 Characterization of the Physical Setting ................................................................... 40 7.1.3 General Site Map ...................................................................................................... 40 7.1.4 Specific Site Map...................................................................................................... 40 7.1.5 Additional Site Maps ................................................................................................ 40 7.1.6 Photographs............................................................................................................... 41

7.2 Refined Human Health Conceptual Site Models ...............................................................44 7.3 Selection of Compounds of Potential Concern..................................................................44

7.3.1 Identified Documentation and Past Site Activity – Site 85 North ............................ 44 7.3.2 Target Analyte List / Target Compound List (modified).......................................... 46 7.3.3 Nondetected Parameters............................................................................................ 48 7.3.4 Human Health Risk-based Screening Using Maximum Concentrations.................. 50 7.3.5 Background Comparison Using Maximum Concentrations ..................................... 50 7.3.6 Data Gaps.................................................................................................................. 51 7.3.7 Data Usability ........................................................................................................... 51 7.3.8 ADEC Human Health Compounds of Potential Concern Data Presentation Table . 51 7.3.9 Human Health Compounds of Concern.................................................................... 51

7.4 Human Health ....................................................................................................................51 7.4.1 Exposure Assessment................................................................................................ 51 7.4.2 Toxicity Assessment ................................................................................................. 57 7.4.3 Risk Characterization................................................................................................ 61

7.5 Results of Preliminary Problem Formulation and Ecological Effects Evaluation.............64 7.5.1 Environmental Setting and Contaminants at the Site ............................................... 64 7.5.2 Contaminants Fate and Transport ............................................................................. 64 7.5.3 Ecotoxicity and Potential Receptors ......................................................................... 64 7.5.4 Completed Exposure Pathways................................................................................. 65


7.6 Calculations for Alternative Risk-Based Cleanup Levels: Human Health........................65 7.6.1 Comparison of Calculated Risk-Based Concentrations to Regulatory Standards .... 66 7.6.2 Consideration of Effects of Leaching to Groundwater ............................................. 66 7.6.3 Uncertainty Assessment............................................................................................ 66 7.6.4 Endocrine Disruptors ................................................................................................ 67

7.7 References..........................................................................................................................69

APPENDIX 7-A – TOXICOLOGICAL PROFILES ....................................................................71

APPENDIX 7-B - ADEC ECOLOGICAL CHECKLIST.............................................................75 FIGURE B.1 – ECOLOGICAL CHECKLIST #1: GENERAL................................................75 FIGURE B.2 – ECOLOGICAL CHECKLIST #2: TERRESTRIAL........................................77 FIGURE B.3 – ECOLOGICAL CHERCKLIST #3: AQUATIC-FLOWING SYSTEMS .......78 FIGURE B.4 – ECOLOGICAL CHECKLIST #4: AQUATIC NON-FLOWING SYSTEMS 78 FIGURE B.5 – ECOLOGICAL CHECKLIST #5: WETLANDS.............................................78

APPENDIX 7-C – MODELING INPUTS ....................................................................................79 TABLE C.1 - HUMAN HEALTH COMPOUNDS OF POTENTIAL CONCERN ADEC DATA PRESENTATION..........................................................................................................79 HUMAN HEALTH CALCULATION EQUATIONS AND PARAMETERS.........................86

TABLE C.2 - RISK EQUATIONS....................................................................................... 86 TABLE C.3 - RISK EQUATION PARAMETERS ............................................................. 88 TABLE C.4 - PHYSICAL CHEMICAL DATA (PC Data) ................................................. 90 TABLE C.5 - TOXICITY INFORMATION........................................................................ 91 TABLE C.6 - INDUSTRIAL RISK AND HAZARD .......................................................... 92

APPENDIX 7-D – HUMAN HEALTH CONCEPTUAL SITE MODEL (CSM) ........................93

8.0 SITE 133 ..............................................................................................................................97 8.1 Site Location and Background – Site 133..........................................................................97 8.2 Identified Documentation and Past Site Activity– Site 133 ..............................................98

8.2.1 Pre-BRAC Investigation Activities........................................................................... 99 8.2.2 1997 Investigation Activities .................................................................................... 99 8.2.3 1998 Investigation Activities .................................................................................... 99 8.2.4 1999 Investigation Activities .................................................................................... 99

8.3 Potential Contaminants ....................................................................................................100 8.4 Synopsis of Contaminant Distribution – Site 133............................................................100

8.4.1 Pre-Remedial Action............................................................................................... 100 8.4.2 Late and Post Remedial Action............................................................................... 100

8.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 85 North ...101 8.5.1 Contamination Source(s) ........................................................................................ 101 8.5.2 Release Mechanism(s) ............................................................................................ 101 8.5.3 Migration Pathways ................................................................................................ 101 8.5.4 Exposure Routes ..................................................................................................... 102 8.5.5 Potential Receptors ................................................................................................. 102

8.6 Data Set............................................................................................................................102 8.6.1 Data Sources ........................................................................................................... 102 8.6.2 Review of Data Set Detection Limits ..................................................................... 103

8.7 ADEC Method Two Criteria............................................................................................105


8.7.1 Initial Screening Process......................................................................................... 105 8.7.2 Elimination of Analytes .......................................................................................... 106 8.7.3 Findings of Initial Screening................................................................................... 106

8.8 Alternative Cleanup Levels..............................................................................................107 8.9 Cumulative Risk...............................................................................................................107 8.10 Leachability Modeling .................................................................................................107 8.11 Complete Exposure Pathways......................................................................................108 8.12 Recommendations – Site 133.......................................................................................108

9.0 SITE 112 ............................................................................................................................110 9.1 Site Location and Background – Site 112........................................................................110 9.2 Identified Documentation and Past Site Activity– Site 112 ............................................110

9.2.1 Pre-BRAC Investigation Activities......................................................................... 110 9.2.2 1997 Investigation Activities .................................................................................. 110 9.2.3 1998 Investigation Activities .................................................................................. 110 9.2.4 1999 Investigation Activities .................................................................................. 111

9.3 Potential Contaminants – Site 112...................................................................................111 9.4 Synopsis of Contaminant Distribution – Site 112............................................................111 9.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 112 ...........111

9.5.1 Contamination Source(s) ........................................................................................ 112 9.5.2 Release Mechanism(s) ............................................................................................ 112 9.5.3 Migration Pathways ................................................................................................ 112 9.5.4 Exposure Routes ..................................................................................................... 113 9.5.5 Potential Receptors ................................................................................................. 113

9.6 Data Set............................................................................................................................113 9.6.1 Data Sources ........................................................................................................... 113 9.6.2 Review of Data Set Detection Limits ..................................................................... 113

9.7 ADEC Method Two Criteria............................................................................................115 9.7.1 Initial Screening Process......................................................................................... 115 9.7.2 Elimination of Analytes .......................................................................................... 115 9.7.3 Findings of Initial Screening................................................................................... 115

9.8 Alternative Cleanup Levels..............................................................................................116 9.9 Cumulative Risk...............................................................................................................116 9.10 Leachability Modeling .................................................................................................116 9.11 Complete Exposure Pathways......................................................................................117 9.12 Recommendations – Site 112.......................................................................................117

10.0 REFERENCES...................................................................................................................119


TABLES Section 4 TABLE 4-1 FORT GREELY WELL INFORMATION TABLE 4-2 TOTAL ORGANIC CARBON CONCENTRATIONS – 1997 THROUGH1999, FORT

GREELY, ALASKA TABLE 4-3 SOIL MOISTURE CONTENT – SITES 85 SOUTH AND 85 NORTH, FORT GREELY,

ALASKA Section 6 TABLE 6-1 DATA SET, SITE 85 SOUTH, FORT GREELY, ALASKA TABLE 6-2 INITIAL SCREENING USING ADEC METHOD TWO LEVELS, SITE 85 SOUTH,

FORT GREELY, ALASKA TABLE 6-3 ALTERNATIVE CLEANUP LEVELS BY ADEC METHOD THREE, SITE 85

SOUTH, FORT GREELY, ALASKA Section 7 TABLE 7-1 Sites 85S, 85N, & 133 COPC TABLE 7-2 COC CONCENTRATIONS TABLE 7-3 ACUTE EXPOSURE DATA TABLE 7-4 ADEC HUMAN HEALTH TOXICITY DATA PRESENTATION TABLE FOR

CARCINOGENIC DATA (MODIFIED) TABLE 7-5 ADEC HUMAN HEALTH TOXICITY DATA PRESENTATION TABLE FOR

NONCARCINOGENIC DATA (MODIFIED) TABLE 7-6 WEIGHT OF EVIDENCE TABLE 7-7 RISK LEVELS TABLE 7-8 ECOTOXICITY TABLE 7-9 ACLS Section 8 TABLE 8-1 DATA SET, SITE 133, FORT GREELY, ALASKA TABLE 8-2 INITIAL SCREENING USING ADEC METHOD TWO LEVELS, SITE 133, FORT

GREELY, ALASKA TABLE 8-3 ALTERNATIVE CLEANUP LEVELS BY ADEC METHOD THREE, SITE 133, FORT

GREELY, ALASKA Section 9 TABLE 9-1 DATA SET, SITE 112, FORT GREELY, ALASKA TABLE 9-2 INITIAL SCREENING USING ADEC METHOD TWO LEVELS, SITE 112, FORT

GREELY, ALASKA TABLE 9-3 ALTERNATIVE CLEANUP LEVELS BY ADEC METHOD THREE, SITE 112, FORT

GREELY, ALASKA


FIGURES FIGURE 1-1 LOCATION MAP, SITES 85 SOUTH, 133, 112, AND 85 NORTH

FIGURE 4-1 WELL LOCATIONS, FORT GREELY, ALASKA

FIGURE 6-1 SAMPLE LOCATION MAP, SITE 85 SOUTH, FORMER FIRE TRAINING PIT, FORT GREELY, ALASKA

FIGURE 6-2 SITE 85 SOUTH, HUMAN HEALTH CONCEPTUAL SITE MODEL

FIGURE 7-1 SAMPLE LOCATION MAP, SITE 85 NORTH, FORT GREELY, ALASKA

FIGURE 8-1 SITE MAP, SITE 133, FORT GREELY, ALASKA

FIGURE 8-2 SITE 133, HUMAN HEALTH CONCEPTUAL SITE MODEL

FIGURE 9-1 SITE MAP, SITE 112, FORT GREELY, ALASKA

FIGURE 9-2 SITE 112, HUMAN HEALTH CONCEPTUAL SITE MODEL

PHOTOGRAPHS PHOTO 1-1 AERIAL PHOTO FORT GREELY, ALASKA

PHOTO 1-2 AERIAL PHOTO FORT GREELY, ALASKA

PHOTO 6-1 SITE 85 SOUTH PHOTOGRAPH

PHOTO 6-2 SITE 85 SOUTH PHOTOGRAPH

PHOTO 7-1 SITE 85 NORTH PHOTOGRAPH

PHOTO 7-2 SITE 85 NORTH PHOTOGRAPH

PHOTO 8-1 SITE 133 PHOTOGRAPH

PHOTO 9-1 SITE 112 PHOTOGRAPH

APPENDICES APPENDIX A DOCUMENTATION SUPPORTING AQUIFER THICKNESS ESTIMATION,

DEPTH TO GROUNDWATER, and SEASONAL GROUNWATER TABLE FLUCTUATION

APPENDIX B DOCUMENTATION SUPPORTING HYDRAULIC GRADIENT ESTIMATION, FORT GREELY, ALASKA

APPENDIX C DOCUMENTATION SUPPORTING AQUIFER HYDRAULIC CONDUCTIVITY ESTIMATION, FORT GREELY, ALASKA

APPENDIX D RESIDENTIAL RISK CALCULATIONS

APPENDIX 85S SUPPORTING DOCUMENTATION FOR SITE 85 SOUTH

APPENDIX 85N SUPPORTING DOCUMENTATION FOR SITE 85 NORTH

APPENDIX 133 SUPPORTING DOCUMENTATION FOR SITE 133

APPENDIX 112 SUPPORTING DOCUMENTATION FOR SITE 112


ACRONYMS AND ABBREVIATIONS

AAC Alaska Administrative Code ACL alternative cleanup level ADEC Alaska Department of Environmental Conservation AGRA AGRA Earth and Environmental, Inc. AK Alaska Method ARAR applicable or relevant and appropriate requirement ASL Alternate screening level BEC BRAC Environmental Coordinator BCT BRAC Cleanup Team bgs below ground surface BRAC Base Realignment and Closure BTEX benzene, toluene, ethylbenzene, and xylenes CERCLA Comprehensive Environmental Response Compensation and Liability Act CERFA Community Environmental Response Facilitation Act CFR Code of Federal Regulations CFU colony-forming units COPC compound of potential concern CX Center of expertise CSM Conceptual Site Model DL Detection Limit DPW Directorate of Public Works DRO Diesel - range organic DAF Dilution and attenuation factor DSERTS Defense Site Environmental Restoration Tracking System EBS Environmental Baseline Survey EE/CA Engineering Evaluation/Cost Assessment E&E Ecology and Environment, Inc. EF Exposure Frequency ELCR Excess lifetime cancer risk EI Engineering Investigation EPA U.S. Environmental Protection Agency FFS Focused feasibility study FSP Field Sampling Plan GPR ground penetrating radar GRO Gasoline-range organic


HI Hazard Index HPC Heterotrophic plate count IC institutional control ISE Initial site evaluation IDW investigation-derived waste Koc organic carbon partitioning coefficient JEG, Jacobs Jacobs Engineering Group Inc. LDR Land Disposal Restriction LOAEL Lowest observed adverse effects level LRA Local Redevelopment Authority LRI Limited Remedial Investigation MCL Maximum contaminant level MPN most probable number mg/kg Milligrams per kilogram ND Not Detected nd Not Detected NFA no further action NOAEL No observable adverse effects level OCP organochlorinated pesticide ODB oil-degrading bacteria OE Ordnances and explosive OSWER Office of Solid Waste and Emergency Response PAH Polynuclear aromatic hydrocarbon PCB polychlorinated biphenyl PID Photo-ionization detector POL petroleum, oil, and lubricants PPE personal protective equipment ppm parts per million PRG Preliminary Remediation Goals QA quality assurance QAPP Quality Assurance Project Plan QC quality control RAB Restoration Advisory Board RBC Risk Based Concentration RCRA Resource Conservation and Recovery Act RI Remedial Investigation


RI/RA Remedial investigation / removal action ROM rough order of magnitudeRRO Residual - range organic SESOIL Seasonal Soil Characteristic Model SI Site Investigation SOP Standard Operating Procedures SSL soil screening level SVOC Semi-volatile organic compound SWMU Solid waste management unit TCLP toxicity characteristic leaching procedure TEF toxicity equivalent factor TEQ toxicity equivalent quotient TERC Total Environmental Restoration Contract TOC total organic carbon TSCA Toxic Substances Control Act USAED U.S. Army Engineer District USARAK U.S. Army, Alaska USCS Unified Soil Classification System UST underground storage tank UXO unexploded ordnance VOC volatile organic compound


1.0 INTRODUCTION This document presents the approach and findings of evaluations conducted by the U.S. Army Engineer District (USAED) Alaska to address four Fort Greely Base Realignment and Closure (BRAC) sites. The subject sites are:

• Site 85 South; • Site 85 North; • Site 133; and • Site 112.

An aerial photograph showing the Fort Greely cantonment area is included as Photo 1-1. Locations of three of the sites are shown on Photo 1-2. Site locations are also shown on Figure 1-1. The work consisted of comparing detected concentrations, (and in some cases detection limits of non-detected compounds) against ADEC Method Two criteria, and performing ADEC Method Three or Method Four risk evaluations. The evaluations included leachability modeling for specific parameters. Recommendations were developed for each site.

1.1 Audience The work is structured for review and evaluation by 1) U.S. Army Alaska (USARAK), 2) Alaska Department of Environmental Conservation (ADEC) and, 3) U.S. Environmental Protection Agency (EPA).

1.2 Purpose Initially this work was intended to aid the BRAC Cleanup Team (BCT) in determining eligibility for parcel reuse by other governmental agencies or non-federal entities. The evaluations were intended to support the BCT’s reuse designation strategy by characterizing environmental concerns at each site and determining the parcel’s transfer suitability. The Department of Defense (DoD) has reconsidered the potential reuse by other entities. DoD now plans to retain the properties in their inventory for future use by DOD.

1.3 Structure of Document This document is structured as follows. 1. Section 1 – INTRODUCTION: Provides an introduction to the work, including audience,

purpose, and document structure. 2. Section 2 – BACKGROUND: Provides summary/description of Fort Greely BRAC activities

and process. 3. Section 3 – GENERALIZED FORT GREELY PHYSICAL CHARACTERISTICS: Provides

generalized description of site location, geology, soils, and hydrogeology. 4. Section 4 –CONDITIONS SPECIFIC TO FORT GREELY CANTONMENT AREA:

Provides information about aquifer thickness, hydraulic gradient, hydraulic conductivity, and fraction organic carbon in soil specific to the Fort Greely cantonment area.

5. Section 5 –PROJECT APPROACH AND TASK BREAKDOWN: Provides a summary of the general approach followed during the work. The methodology of calculating site-specific Cleanup Levels is described in this section.


6. Section 6 – SITE 85 SOUTH: Presents site information, methodology of evaluation, findings, and recommendations for Site 85 South.

7. Section 7 - SITE 85 NORTH: Presents site information, methodology of evaluation, findings, and recommendations for Site 85 North. This section was initially prepared to be an independent document. However, the section has now been fitted into the overall document as a discrete section. Consequently, this section differs in format from the other site sections in that it contains its own additional appendices and reference sections located within the site section itself. This section does reference the main body of the report (Section 1 through 5).

8. Section 8 – SITE 133: Presents site information, methodology of evaluation, findings, and recommendations for Site 133.

9. Section 9 – SITE 112: Presents site information, methodology of evaluation, findings, and recommendations for Site 112.

10. Section 10 – References: Presents the references used throughout this report.

Site-specific sections (Sections 6, 7, 8, and 9) provide the following information: • discussion of general background site information; • summary of prior site activity and existing data; • compounds of potential concern (COPCs); • synopsis of contaminant distribution; • human health conceptual site model to include potential exposure pathways; • summary of the approach used to conduct soil evaluation; • results of the soil evaluation; • cumulative risk evaluation; and • recommendations.

A separate appendix is included for each site. Each appendix contains copies of pertinent documentation from existing reports and other sources, including analytical summary tables, boring logs, and site maps, etc.

Date: 01 July 1999 Description: Aerial Photograph of Ft Greely area.

Photo1-1

AERIAL PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

22 February 2002

REVISIONS:

N

SITE 85 NORTH

SITE 133

SITE 85 SOUTH

SITE 112 approximately 300 feet south Date: unknown Description: Aerial Photograph of Ft Greely

Photo1-2

AERIAL PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

22 February 2002

REVISIONS:

N

FortGreely

Map Location

SITE 85

SOUTH

SITE 85

NORTH

SITE 133

SITE 112


2.0 BACKGROUND Background discussion for Fort Greely BRAC activities is taken (with adaptations and additions) from the April 1999 Jacobs Engineering Group (JEG) report titled 1998 Remedial Investigation Report, Fort Greely, Alaska.

Evaluations and investigations were performed as part of the BRAC process. Through this process the number of buildings controlled by the U.S. Army at Fort Greely was expected to decrease from over 200 to about 30. The surplus facilities, as well as selected undeveloped areas, were to be eligible for reuse by other government and non-government entities. To facilitate potential land transfers under the BRAC process, the BRAC environmental restoration program was implemented to provide information on the environmental condition of the eligible BRAC properties and to initiate cleanup activities, as necessary.

Changes have recently occurred that affect the potential future use of the properties. Current land use at the four sites is industrial/commercial. The subject sites will remain in DOD inventory. Land use is expected to remain industrial/commercial. The sites are vacant and three of the sites are located very near Allen Army Airfield on Fort Greely. There is now no plan to excess or transfer these properties.

The following environmental activities were conducted at Fort Greely under the BRAC program:

• Environmental Baseline Survey (EBS: Woodward-Clyde 1996);

• 1997 Site Investigation/Limited Remedial Investigation (SI/LRI: Jacobs, September 1998), [investigation at 26 Fort Greely sites];

• 1998 Remedial Investigation (RI: Jacobs, April 1999), [limited remedial investigation or engineering investigation at 33 Fort Greely sites];

• 1999 Remedial Investigation/Removal Action (RI/RA: Jacobs, August 2000), [additional investigation at 11 Fort Greely sites and removal action at two sites];

• 2000 Remedial Investigation / Removal Action (RI/RA: Jacobs, Draft June 2001), [additional removal action at two sites, IDW disposal];

• 2000 Thermal Treatment (Jacobs, June 2001), [thermal treatment of excavated soils];

• Limited Risk Evaluation [ADEC Method 3 evaluation of 6 other sites]; and

• Groundwater Monitoring.

Earlier environmental investigation and remedial activities took place at some BRAC sites prior to the BRAC program. Previous studies conducted at Fort Greely have included both comprehensive post evaluations and individual parcel investigations. A summary of the available previous information was compiled by Woodward-Clyde in the 1996 Environmental Baseline Survey (EBS) (Woodward-Clyde 1996).


3.0 GENERALIZED FORT GREELY PHYSICAL CHARACTERISTICS Generalized physical characteristics of the Fort Greely BRAC area of interest are described below. The information provided is based on the references listed in Section 10.

3.1 Location Fort Greely is located in interior Alaska, approximately 110 miles southeast of Fairbanks and directly south of Delta Junction (see Figure 1-1 inset). The post encompasses an area of approximately 640,000 acres. Areas previously identified as surplus property under BRAC (including reserve enclaves) comprised approximately 1,830 acres. The post is currently used as a cold weather training and testing facility for the U.S. Army.

3.2 Regional Geology Fort Greely is located within the Delta River outwash plain and is generally characterized by flat to gently rolling topography, sloping generally toward the north, with bottomland forests and wetlands.

The main cantonment area is located on a low alluvial terrace in a region dominated by alluvial fans, moraines, and river floodplains. At least three glacial advances have covered the area. The moraine deposits, generally consisting of silty, sandy gravel to sandy, gravely silt, are bordered by alluvial outwash fans. The alluvial fans are characterized by sandy gravel inter-bedded with lenses of sand and silt. Peat and loess generally cover the alluvial deposits ranging from a few inches to several feet thick.

The alluvial and glacial deposits have been estimated to be up to 2,500 feet thick. These deposits are bordered on the south and underlain by crystalline bedrock common to the Alaska Range. Discontinuous permafrost has been reported in the region to depths of 120 feet.

3.3 Soils - Fort Greely Cantonment Area Borings have been drilled and logged at Fort Greely during 1997 through 1999 BRAC field activities, as well as prior site-specific work not directly associated with the BRAC program. Soil types vary with depth. Soils encountered included peat, silt, and coarse-grained soils (sand and gravel) with a broad range of silt content. Based on soil boring logs, there appears to be lateral similarity between borings with respect to general soil types at given depths in the upper 250 feet below ground surface (bgs). The exception to this is the intermittent presence of a silt-rich unit encountered at approximately 30 to 40 feet bgs at many, but not all, locations on the cantonment area.

In undeveloped areas, surface soil generally consists of organic peat and loess to a depth ranging from 1 to 2 feet bgs. Surface soil in developed parcels generally consists of sandy, silty gravel. A transition zone, consisting of increasing grain size and decreasing silt and sand content, was generally observed between the surface soil and approximately 5 feet bgs. This zone likely includes materials comprising the outwash apron, grading to underlying glacial till and alluvial materials. A laterally uniform stratum of dense, poorly graded sand and gravel with cobbles was observed below 5 feet bgs. The depth of these coarse-grained soils generally extends to roughly 30 to 40 feet bgs, with depth variability depending on location. Borings drilled at several sites


indicated that this stratum contains occasional silt and sand lenses, and extends to variable depths. A silt-rich stratum was identified below this coarse-grained unit at many locations.

The depths and locations of the silt-rich strata are of particular interest, due to their impact on contaminant migration patterns. At several sites, high silt-content, low-permeability, formations appear to have retarded vertical COPC migration, resulting in contaminant accumulation and lateral spread directly above, and in the upper part of the silt-rich formation’s interface with overlying gravel. Unlike the gravel located between the surface and approximately 30 feet bgs, the depth, thickness and lateral extent of the silty strata varied across the post. At Site 30, silt-rich soil was identified at approximately 40 feet bgs. Similar soil was encountered at approximately 30 feet bgs at Site 73, and at approximately 25 feet bgs at Building 101 on north post near the airfield.

The thickness of the silt-rich strata varies with location. The silt-rich strata appeared to extend to at least 70 feet bgs at both Site 30 and Site 73. Soil samples collected at Site 73 indicated a variable thickness within the site boundaries. In comparison, a similar semi-confining layer was not encountered at Site 119, although borings at Site 119 were advanced to a maximum depth of only 61.5 feet bgs. Site 119 is located less than 2,000 feet from Site 30 where the silty stratum was present at 30 feet bgs. These observations are consistent with what would be expected in glacial and fluvial deposits, which characteristically contain lenticular, discontinuous strata of fine-grained soil.

3.4 Surface Water Hydrology Fort Greely’s main cantonment area is bounded on the north and east by Jarvis Creek, a tributary of the Delta River. Jarvis Creek flows north. Both Jarvis Creek and the Delta River are fed by glacial melt-water, and are augmented in the summer months by rainfall and surface runoff. Other creeks and lakes are scattered throughout the post, outside the main cantonment area.

3.5 Hydrogeology Groundwater in the Fort Greely region reportedly exists in perched water zones and in an underlying unconfined aquifer. During the 1997 through 1999 BRAC field efforts, perched water was not encountered in soil borings. The maximum soil boring depth in 1998 was 78 feet (AP-855) at Site 30. The maximum soil boring depth in 1999 was 255 feet (AP-1199, monitoring well 88-MW-A at Site 88.

According to a 1991 U.S. Army Corps of Engineers report titled “Groundwater Monitoring Network, Fort Greely, Alaska,” the groundwater depth ranges from 175 to 215 feet bgs, depending on location, and can exhibit seasonal variations of up to 50 feet (USAED 1991). However, a 50-foot variation has not been substantiated by sampling conducted in the past 11 years. This recent data suggests seasonal variation of approximately 20 feet. A hydraulic gradient of 0.001 to 0.004 foot per linear foot was calculated for the 1991 USAED report, with flow direction to the northeast through the main cantonment area.

Based on sampling conducted during the past 11 years, the depth to groundwater below the ground surface across the cantonment (not including the landfill area to the south) is estimated to range from 171 feet to 222 feet, depending on well location and time of measurement.

The groundwater in the region is recharged by snowmelt and precipitation at an estimated rate of 1 inch per year. Additionally, it is reported that the upper Delta River, Jarvis Creek, and other


smaller creeks provide recharge to the groundwater. The regional aquifer is bordered on the south by the Alaska Range and discharges near the mouth of the Delta River, Clearwater Creek, and Clearwater Lake (USAED 1991). Discontinuous areas of perched water and permafrost have been reported in the area. Based on the depth of static groundwater at Fort Greely cantonment and the absence of groundwater encountered during the 1997 and 1998 BRAC SI/LRI field activities, permafrost does not form a continuous or widespread confining layer in the cantonment area.

An evaluation of the existing groundwater monitoring network was also included in the USAED report (USAED 1991). According to this report, a total of 22 wells (seven monitoring wells and 15 supply wells) are located at Fort Greely. The seven monitoring wells are constructed of six-inch diameter casings and are completed to depths ranging from 219 to 240 feet bgs. The screened portions of the wells have varied lengths between 65 and 80 feet.

Between 1990 and 1995, at least seven discrete groundwater sampling events were conducted using these wells. Results of the sampling events did not indicate patterns of volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), gasoline-range organic compounds (GRO), diesel range organics (DRO), pesticides, polychlorinated biphenyls (PCBs), dissolved metals, or radioisotope concentrations that exceed background levels and/or maximum contaminant level (MCLs). Although several low-level detections did occur, re-sampling was conducted, and the detections were not repeatable. Detections were attributed to laboratory or sampling interference. A summary of the seven sampling events is contained in the 1997 SI/LRI Report (Jacobs, 1998) and Appendix A in the 1998 RI Report (Jacobs, 1999).

Nine additional groundwater monitoring wells were installed at Fort Greely during the 1999 BRAC field activities. Samples were collected from these wells, and the results are presented in the 1999 Summary Report (Jacobs, 2000).

Groundwater sampling has been conducted twice per year from 1999 through 2002. Three additional monitoring wells were installed and sampled in Fall 2002.


4.0 CONDITIONS SPECIFIC TO THE FORT GREELY CANTONMENT AREA ADEC Method Three/Four Risk Evaluation procedures allow for the modification of several soil and aquifer input parameters. The following site-specific parameters were evaluated:

• aquifer thickness; • hydraulic gradient; • aquifer hydraulic conductivity; • fraction organic carbon in soil; and • soil moisture.

4.1 Aquifer Thickness – Fort Greely Cantonment Area A boring has not been drilled at Site 85 South, Site 85 North, or Site 133 that extended to groundwater. However, numerous borings have been drilled to groundwater at other locations across the Fort Greely cantonment. Information regarding these borings and wells is shown in Table 4-1. Well locations are shown in Figure 4-1. Supporting documentation is included in Appendix A.

Borings AP-1196 through AP-1204 were drilled at Fort Greely during 1999, with groundwater monitoring wells installed. Locations (Figure 4-1) were spread across the cantonment. The depths of these borings ranged from 214 to 255 feet bgs. Reported depths to groundwater ranged from 184.23 to 218.18 feet bgs. Available information supports an aquifer thickness of at least 19 to 52 feet at these locations. Note that the base of the aquifer was not identified in these borings. These thickness values are based on the terminal depth of drilling, thus actual aquifer thickness may exceed these figures. Soils in the aquifer interval are generally reported as sandy gravel and gravelly sand with Unified Soil Classification System (USCS) classifications of GP, GW, and SP. A lense of silty gravel (GM) was reported in the AP-1204 aquifer interval.

Borings for wells A, B, C, D1, D2, E1, and E2 were drilled at Fort Greely during October 1984, with groundwater monitoring wells installed. Locations (Figure 4-1) extend across the cantonment, generally down-gradient (northeast) from the Robin Road fuel spill site (BRAC Site 30). The depths of these borings ranged from 219 to 240 feet bgs. Based on available depth to water information, these borings support aquifer thickness of at least 20 to 48 feet. Again, note the base of the aquifer was not identified in these borings. These figures are based on the terminal depth of drilling, thus aquifer thickness may exceed these figures. Soils in the aquifer interval were generally reported as sand and gravel with USCS classifications of GP, GW, and SP. Logs for these borings specifically indicate fines content less than 5% at multiple locations in the aquifer interval. A lens of sand with silt (SP-SM) was reported in the well E1 aquifer interval (approximately 215 feet bgs). A lens of silty gravel (GM) was reported in the well E2 aquifer interval (approximately 210 feet bgs).

Borings for well #1 through well #10, except well #8, were drilled at Fort Greely from September 1943 through June 1954 to reported depths ranging from 198 to 260 feet bgs. Approximate locations are shown in Figure 4-1. Based on available depth to water information, these borings support aquifer thickness of at least 23 to 69 feet. Insufficient information was found to evaluate well #8. Soils in the aquifer interval are generally reported as sand and gravel.

Borings for well #11, well #12, and well #13 (Figure 4-1) provided deeper soils and aquifer information than the borings described above. These borings were drilled to 332 feet bgs.


Reported depth to water ranged from 191 to 200 feet bgs. Based on available depth to water information, these borings support aquifer thickness of at least 131 to 141 feet. Note that the base of the aquifer was not identified in these borings. These figures are based on the terminal depth of drilling, thus aquifer thickness may exceed these figures. Soils in the aquifer interval were generally reported as sand and gravel with USCS classifications of GP, GW, and SP. Some lenses of silty sand and silty gravel are indicated on logs. Based on a pumping test conducted at well #12 on 3 November 1959 and available well construction information, the aquifer is confirmed to be hydraulically connected between soils near the unconfined aquifer water table and deeper soils at the screened interval.

Based on available drilling information, as described above, aquifer thickness of at least 131 feet (40 meters) is supported for the area near well #11, well #12, and well #13. This area is approximately 5,000 feet southwest of Site 85 South, 5,200 feet southwest of Site 85 North, 4,800 feet south of Site 133, and 3,200 feet southeast of Site 112.

4.2 Hydraulic Gradient – Fort Greely Cantonment Area Identified references that provide information on hydraulic gradient at Fort Greely follow. Supporting documentation is included in Appendix B.

• Alaska District, (approximately 1959) Marked-up Fort Greely map showing groundwater table contours. Base map is CE File No. 18-04-61, File 20-29 "Marked Drawing". Based on contour lines drawn on the map, the hydraulic gradient is approximately 0.002 ft./ft. Flow direction is northeast.

• Alaska District, (approximately 1983) Groundwater Contour Map, Fort Greely, Alaska, Assessment of Groundwater Monitoring Network, Figure 5. Based on contour lines shown on the map, the hydraulic gradient is approximately 0.002 ft./ft. Flow direction is northeast.

• Alaska District (August 1991) Groundwater Monitoring Network Fort Greely, Alaska. Based on contour lines shown on Figure 4, the hydraulic gradient is approximately 0.002 ft/ft. Flow direction is northeast.

• Jacobs Engineering Group (August 2000) Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska. Based on contour lines shown on Figure 4-1 of that report, the hydraulic gradient ranges from approximately 0.002 to 0.007 ft./ft, depending on location. Large-scale flow direction is northeast.

4.3 Hydraulic Conductivity – Fort Greely Cantonment Area The December 1959 USAED/USGS document titled Direction of Ground-Water Movement at Fort Greely, Alaska [stamped “Preliminary Report Subject To Revision”] provides information from a pump test conducted at well #12 on 03 November 1959. Although field notes are not provided with the document (and were not found in USAED files), a map showing groundwater table contours during pumping is provided in the document (see Appendix C). It appears that observation wells used during the pump test included well #8, well #9, well #10, well #11, well #13, and well #14. The pumping rate was indicated to be 1,500 gpm.

The following equation, from Driscoll (1989) was used to estimate hydraulic conductivity from this data.


Q = K (H2-h2) 1,055 log R/r

where:

Q = well yield or pumping rate, in gpm [1,500 gpm]; K = hydraulic conductivity of the water-bearing formation, in gpd/ft2 [solve for K]; H = static head measured from bottom of aquifer, in feet [131.1 feet]; h = depth of water in the well while pumping, in feet [121.9 feet];

R = radius of the cone of depression, in feet [700 feet]; and r = radius of the well, in feet [0.75 feet].

The calculation results in a hydraulic conductivity estimate of approximately 2,019 gpd/ft2 , or 30,005 m/yr. This value is within the range of hydraulic conductivity for clean sand reported by Freeze and Cherry (1979).

4.4 Fraction Organic Carbon in Soil – Fort Greely Cantonment Area Total organic carbon (TOC) information and selected text below is taken from the April 1999 Jacobs report titled 1998 Remedial Investigation Report, Fort Greely, Alaska. Table 4-2 provides a listing of total organic carbon analytical results from Fort Greely.

TOC analysis was not conducted during pre-1998 site investigation activities at the subject sites. Three samples from Sites 85 North and 85 South were analyzed for TOC during 1998 to determine the soil's sorptive capacity and ability to retard contaminant transport. Samples collected from 15 to 17 feet bgs in borings AP-914 and AP-916 contained TOC concentrations of 0.3575 percent and 0.7461 percent respectively. A lower TOC concentration of 0.2563 percent was reported for the sample from 20 to 22 feet bgs in boring AP-915. The samples tested for TOC were not tested for petroleum, oil and lubricate (POL) contamination. Therefore, the relative influence of hydrocarbon content cannot be accurately assessed.

The results of all TOC analyses conducted on Fort Greely samples during the 1997 through 1999 BRAC investigation activities were tabulated (see Table 4-2). Those samples considered impacted by hydrocarbon contamination were separated out from the TOC data set. Samples that were not analyzed for POL, but are probably not impacted (based on field screening) were also separated out of the TOC data set. The remaining TOC concentrations ranged from 0.03 to 0.7 percent. As shown in Table 4-2, the average TOC concentration of these latter results from samples not impacted by hydrocarbon contamination was 0.15 percent (0.0015).

4.5 Soil Moisture Content Data from prior reports (Jacobs 1998 and 1999) indicates a range of soil moisture content at Fort Greely, ranging from about 1.5 to 5 percent. Moisture contents from sampling at Sites 85 South and 85 North are tabulated in Table 4-3. Samples from the upper three feet were screened out of the data set because they appeared to be impacted by precipitation events. As shown in Table 4-3, moisture content ranged from 0.6 percent to 12.4 percent.

FortGreely

Map Location

SITE 85

SOUTH

SITE 85

NORTH

SITE 133

SITE 112

TABLE 4-1FORT GREELY WELL INFORMATION

Well ID Boring ID Date Completed

Boring Depth (ft. bgs)

Date Depth to Water (ft.)

Min. Aquifer Thickness

(ft.)

Reported Aquifer Soil Types (USCS Symbol as available)

Pump Test Information

Well #1 Sep-43 235 183.8 (5/16/89) 51.2 sand and fine gravel, silty sandy gravel, coarse gravel and sand

Well #2 Sep-43 198 172.9 (11/2/59) 23.1Well #3 Sep-43 198 169.2 (11/2/59)

177.3 (5/16/89)28.8, 20.7 Medium and fine gravel and sand, gravelly

sand, coarse gravelWell #4 Sep-48 215 172.2 (11/2/59)

180.5 (5/16/89)42.8, 34.5 fine and coarse sand and gravel, sand and

small gravelWell #5 219 195 (5/16/89) 24Well #6 Nov-48 218 185.5 (11/2/59)

192.7 (5/16/89)32.5, 25.3

Well #7 230 195.8 34.2Well #8 Jun-54 396Well #9 Jul-53 260 190.6 (11/2/59) 69.4

Well #10 Jul-53 252 198.9 (11/2/59 53.1Well #11 Oct-59 332 200.6 (11/3/59) 131.4 sand and gravel some silt, (GP), sand

gravel GM, gravel, gravel sand silt, sand and gravel water bearing, silty sandy gravel, gravelly sand (SW), SP, GW, SP, GP

18 ft. drawdown at 1,500 gpm

Well #12 Sep-59 332 200.9 (11/2/59) 131.1 sandy gravel (GP), silty sandy gravel, clean sandy gravel, sandy gravel

9.5 ft. drawdown at 1,500 gpm

Well #13 Aug-59 332 199.8 (11/2/59) 191.0 (5/16/89)

132.2, 141.0 sandy gravel (GP), sandy gravel (GW), sandy gravel some silt, gravelly sand (SP), silty gravel, silty sandy gravel

8 ft. drawdown at 1,500 gpm [see also 12/59 USGS preliminary report]

Well #14 Feb-61 249Well #15 Jul-68 317Well #16 Sep-68 300Well #17 Sep-88 235

A Oct-84 239 212.9 (5/16/89) 26.1 sand and gravel, silt content <5%, GP, SP

B Oct-84 240 211.0 (5/16/89) 29 coarse sand/fine gravel, gravelly sand with trace silt (SP), sandy gravel (GP)

FTG Information Tables - General.xls, FTG Well Information Page 1 of 2, 12/18/2002

TABLE 4-1FORT GREELY WELL INFORMATION

Well ID Boring ID Date Completed

Boring Depth (ft. bgs)

Date Depth to Water (ft.)

Min. Aquifer Thickness

(ft.)

Reported Aquifer Soil Types (USCS Symbol as available)

Pump Test Information

C Oct-84 239.5 191 (drilling) 48 sandy gravel (GP), sandy gravel, fine to medium gravel, trace silt <5% below 210 ft.

D1 Oct-84 220 199.3 (5/16/89) 20.7 sand with some gravelD2 Oct-84 219 172 (reported

during drilling)47 sand with some gravel, gravelly sand,

medium to coarse sand, occasional cobbles

E1 Oct-84 220.5 193.3 (5/16/89) 27.2 SP sand, gravelly to very gravelly, fine to medium gravel with some sand lenses, silt trace to <5%, lense of SP-SM at 215 ft., SP sand

E2 Oct-84 222 182.0 (5/16/89) 40 medium sandy gravel (GW), lense of GC and GM at 210-215 feet, sandy gravel

30-MW-C AP-1196 07/30/99 248 218.18 29.8 gravelly sand (SP), gravel (GW), sandy gravel (GP)

73-MW-A AP-1197 08/04/99 237 184.25 52.7 sandy gravel (GP), 32-MW-A AP-1198 08/12/99 215 193.17 21.8 sandy gravel (GW), gravelly sand (SP),

sandy gravel (GP)88-MW-A AP-1199 08/19/99 255 203.35 51.6 sandy gravel (GW), sand (SP), gravel (GP)

88-MW-B AP-1200 08/23/99 214.5 193.18 21.3 sandy gravel (GW)73-MW-B AP-1201 08/25/99 214 184.23 29.7 sandy gravel (GP)31-MW-A AP-1202 08/30/99 228 204.89 23.1 sandy gravel (GW)31/32/112-

MW-AAP-1203 09/02/99 214 192.39 21.6 sandy gravel (GW), gravel (GW), sand

(SP)88-MW-C AP-1204 09/15/99 220 200.47 19.5 silty gravel (GM), sandy gravel (GW),

Landfill Well AP-615 Aug-93 299 272.7 (3/14/94) 273.3 (7/29/94)

26.3, 25.7

Landfill Well AP-616 Aug-93 300 290.7 (3/14/94) 290.7 (7/29/94)

9.3

Landfill Well AP-617 Sep-93 302 287.0 (3/14/94) 287.0 (7/29/94)

15

FTG Information Tables - General.xls, FTG Well Information Page 2 of 2, 12/18/2002

TABLE 4-2TOTAL ORGANIC CARBON CONCENTRATIONS - 1997 THROUGH 1999

FORT GREELY, ALASKA

SampleDepth

(feet bgs) Date TOC (%) Site CommentsHydrocarbon

Impacted

AP-862 S7 35 - 37 1998 0.259 Site 73Sample analyzed for POL. Analytical results support sample was impacted by hydrocarbon. Impacted

AP-862 S9 45 - 47 1998 0.1837 Site 73Sample analyzed for POL. Analytical results support sample was impacted by hydrocarbon. Impacted

AP-955 S7 35 - 36.5 1998 1.8 Site 116Sample not analyzed for POL constituents. Field screening indicates sample is probably impacted by hydrocarbons. Impacted

AP-1177 5 - 8 1999 0.58 Site 72Sample analyzed for POL. Analytical results support sample was impacted by hydrocarbon. Impacted

AP-1178 5 - 7 1999 0.25 Site 72Sample analyzed for POL. Analytical results support sample was impacted by hydrocarbon. Impacted

AP-862 S11 55 - 56.5 1998 0.1257 Site 73Sample analyzed for POL. Analytical results support sample was slightly impacted by hydrocarbon. Minor Impact

AP-863 S9 65 - 67 1998 0.1506 Site 73Sample analyzed for POL. Analytical results support sample was very slightly impacted by hydrocarbon. Minor Impact

AP-1180 10 - 12 1999 0.17 Site 102Sample analyzed for POL. Analytical results support sample was probably slightly impacted by hydrocarbon. Minor Impact

AP-906 S3 20 - 22 1998 0.2803 Site 77Sample not analyzed for POL. Field screening results support sample may have been very slightly impacted by hydrocarbon.

Possibly Minor Impact

AP-914 S4 15 - 17 1998 0.3575 Site 85 SouthSample not analyzed for POL constituents. Field screening indicates some POL may be present.

Probably Impacted

AP-916 S4 15 - 17 1998 0.7461 Site 85 NorthSample not analyzed for POL constituents. Field screening indicates some POL may be present.

Probably Impacted

Average of above results: 0.45 POL-impacted, or probably impacted

AP-925 S3 10 - 11.5 1998 0.17 Site 100Sample not analyzed for POL constituents. Field screening indicates POL contamination is not likely to be present.

Probably Not Impacted

30-MW-C 96.25 - 96.5 1999 0.21 Site 30 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

30-MW-C 177.5 - 177.75 1999 0.11 Site 30 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

31-MW-A 76.5-77 1999 0.11 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

32-MW-A 98.25-98.75 1999 0.06 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

32-MW-A 119.5-120 1999 0.08 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

FTG Information Tables - General.xls, FTG TOC Page 1 of 3, 12/18/2002


FORT GREELY, ALASKA

SampleDepth


Impacted31, 32, 112-

MW-A 135-135.5 1999 0.06 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not


MW-A 137-137.5 1999 0.11 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not


MW-A 175.5-176 1999 0.14 Site 31, 32, 112 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

AP-773 S5 25 - 27 1997 0.145 Site 73Sample not analyzed for POL constituents. Field screening indicates POL contamination is not likely to be present.


AP-775 S2 10 - 12 1997 0.367 Site 73Sample not analyzed for POL. Field screening results support sample may have been very slightly impacted by hydrocarbon.


73-MW-A 115-115.5 1999 0.06 Site 73 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

73-MW-A 174.5-175 1999 0.11 Site 73 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

73-B 134.5-135 1999 0.25 Site 73 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

AP-905 S4 20 - 21.5 1998 0.1159 Site 77Sample not analyzed for POL constituents. Field screening indicates POL contamination is not likely to be present.


AP-915 S5 20 - 22 1998 0.2563 Site 85 NorthSample not analyzed for POL constituents. Field screening indicates POL contamination is not likely to be present.



Impacted


Impacted

88-MW-A 196.5-197 1999 0.24 Site 88Samples not expected to be impacted by hydrocarbons. Note: stated incorrectly as 0.024 in 1999 Report Table 4-8.


88-MW-B 95-95.5 1999 0.11 Site 88Samples not expected to be impacted by hydrocarbons. Note: stated incorrectly as 0.011 in 1999 Report Table 4-8.


88-MW-B 155.5-156 1999 0.07 Site 88 Samples not expected to be impacted by hydrocarbons.Probably Not

Impacted

88-MW-C 76-76.5 1999 0.32 Site 88 Samples not expected to be impacted by hydrocarbons.Probably Not

ImpactedAverage of above results: 0.15 Probably not POL-impacted (but not analyzed for POL)



FORT GREELY, ALASKA

SampleDepth


Impacted

AP-1180 30 - 32 1999 0.09 Site 102Sample analyzed for POL. Analytical results support sample was not impacted by hydrocarbon. Not Impacted



AP-956 S5 25 - 27 1998 0.1797 Site 116

Sample analyzed for POL. Analytical results support sample was not significantly impacted by hydrocarbon. Note DRO was detected at 5 mg/kg. Not Impacted

AP-972 S6 30 - 31.5 1998 0.696 Site 119Sample analyzed for POL. Analytical results support sample was not impacted by hydrocarbon. Not Impacted











Average of above results: 0.15 Not impacted by POLThe sample data above was taken from the following references.1. Jacobs Engineering Group (September 1998) 1997 Site Investigation/Limited Remedial Investigation Report, Fort Greely, Alaska.2. Jacobs Engineering Group (April 1999) 1998 Remedial Investigation Report, Fort Greely, Alaska.3. Jacobs Engineering Group (August 2000) Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska.


TABLE 4-3SOIL MOISTURE CONTENT - SITES 85 SOUTH AND 85 NORTH

FORT GREELY, ALASKA

Sample Date SiteDepth

(feet bgs)Percent Solids

Moisture Content (%)

Average Moisture Content (%) (for

each sample)85-008-SO 7/22/1998 85 North 1 97.01 3.085-008-SO 7/22/1998 85 North 1 97.17 2.885-008-SO 7/22/1998 85 North 1 97.72 2.385-012-SO 7/22/1998 85 South 1 93.76 6.285-012-SO 7/22/1998 85 South 1 92.82 7.285-012-SO 7/22/1998 85 South 1 89.6 10.485-021-SO 9/4/1998 85 South 1 96.4 3.685-021-SO 9/4/1998 85 South 1 95.2 4.885-021-SO 9/4/1998 85 South 1 96.5 3.585-021-SO 9/4/1998 85 South 1 96.5 3.585-024-SO 9/4/1998 85 South 1 96.2 3.885-024-SO 9/4/1998 85 South 1 97.4 2.685-024-SO 9/4/1998 85 South 1 96.5 3.585-024-SO 9/4/1998 85 South 1 96.4 3.685-027-SO 9/4/1998 85 South 1 76.7 23.385-027-SO 9/4/1998 85 South 1 75.9 24.185-027-SO 9/4/1998 85 South 1 78.6 21.485-027-SO 9/4/1998 85 South 1 76.9 23.185-028-SO 9/4/1998 85 South 1 77.3 22.785-028-SO 9/4/1998 85 South 1 77.6 22.485-028-SO 9/4/1998 85 South 1 79.6 20.485-028-SO 9/4/1998 85 South 1 78.8 21.285-033-SO 9/8/1998 85 South 1 95.3 4.785-033-SO 9/8/1998 85 South 1 94.5 5.585-033-SO 9/8/1998 85 South 1 94.1 5.985-033-SO 9/8/1998 85 South 1 95.1 4.985-034-SO 9/8/1998 85 South 1 95 5.085-034-SO 9/8/1998 85 South 1 94.2 5.8035-SL 1992 85 South 2 10.7135-SL 1992 Site 133 2.5 12.9138-SL 1992 Site 133 2.5 21.685-002-SO 7/21/1998 85 South 11 94.67 5.385-002-SO 7/21/1998 85 South 11 95.96 4.085-002-SO 7/21/1998 85 South 11 93.6 6.4 5.385-003-SO 7/21/1998 85 South 21 93.66 6.385-003-SO 7/21/1998 85 South 21 95.58 4.485-003-SO 7/21/1998 85 South 21 95.7 4.3 5.085-006-SO 7/22/1998 85 North 6 96.39 3.685-006-SO 7/22/1998 85 North 6 94.64 5.485-006-SO 7/22/1998 85 North 6 97.5 2.5 3.885-009-SO 7/22/1998 85 North 10 93.32 6.785-009-SO 7/22/1998 85 North 10 95.23 4.885-009-SO 7/22/1998 85 North 10 96.2 3.8 5.185-010-SO 7/22/1998 85 North 26 93.05 7.085-010-SO 7/22/1998 85 North 26 94.95 5.1

FTG Information Tables - General.xls, Moisture Content Page 1 of 2, 12/18/2002

TABLE 4-3SOIL MOISTURE CONTENT - SITES 85 SOUTH AND 85 NORTH

FORT GREELY, ALASKA

Sample Date SiteDepth

(feet bgs)Percent Solids

Moisture Content (%)

Average Moisture Content (%) (for

each sample)85-010-SO 7/22/1998 85 North 26 94.9 5.1 5.785-011-SO 7/22/1998 85 North 46 97.36 2.685-011-SO 7/22/1998 85 North 46 98.4 1.685-011-SO 7/22/1998 85 North 46 97.6 2.4 2.285-015-SO 7/21/1998 85 South 6 97.1 2.9 2.985-016-SO 7/21/1998 85 South 16 94.5 5.5 5.585-018-SO 7/22/1998 85 North 21 97.4 2.6 2.685-019-SO 7/22/1998 85 North 16 87.6 12.4 12.485-022-SO 9/4/1998 85 South 11 96.7 3.385-022-SO 9/4/1998 85 South 11 96.8 3.285-022-SO 9/4/1998 85 South 11 97.5 2.585-022-SO 9/4/1998 85 South 11 97 3.0 3.085-023-SO 9/4/1998 85 South 31 97.6 2.485-023-SO 9/4/1998 85 South 31 97.9 2.185-023-SO 9/4/1998 85 South 31 97.7 2.3 2.385-025-SO 9/4/1998 85 South 11 97.2 2.885-025-SO 9/4/1998 85 South 11 97.1 2.985-025-SO 9/4/1998 85 South 11 97.9 2.185-025-SO 9/4/1998 85 South 11 97.3 2.7 2.685-026-SO 9/4/1998 85 South 31 97.3 2.785-026-SO 9/4/1998 85 South 31 97.4 2.685-026-SO 9/4/1998 85 South 31 97.6 2.4 2.685-029-SO 9/4/1998 85 South 11 90.3 9.785-029-SO 9/4/1998 85 South 11 90.2 9.885-029-SO 9/4/1998 85 South 11 90 10.085-029-SO 9/4/1998 85 South 11 91.6 8.4 9.585-030-SO 9/4/1998 85 South 21 96 4.085-030-SO 9/4/1998 85 South 21 96 4.085-030-SO 9/4/1998 85 South 21 96.2 3.8 3.985-036-SO 9/8/1998 85 South 11 96.7 3.385-036-SO 9/8/1998 85 South 11 96.7 3.385-036-SO 9/8/1998 85 South 11 96.9 3.185-036-SO 9/8/1998 85 South 11 97.3 2.7 3.185-037-SO 9/8/1998 85 South 36 98 2.085-037-SO 9/8/1998 85 South 36 98.3 1.7 1.9095-SL 1992 85 North 35.5 0.6 0.6080-SL 1992 85 North 5.5 8.5 8.5060-SL 1992 85 North 30.5 3.5 3.5

RANGE: 0.6 - 12.4 %AVERAGE: 4.4

Note: Samples in the upper 3 feet below ground surface are not included in the range and average.

FTG Information Tables - General.xls, Moisture Content Page 2 of 2, 12/18/2002


5.0 PROJECT APPROACH AND TASKS The work approach and specific tasks incorporate information from the 19 and 20 June 2000 meetings held between USARAK, EPA, ADEC, JEG, and USAED. The approach also incorporates review comments on the July 2000 USAED document titled Approach Document, Soil Screening, Fort Greely BRAC Site 85 South, Site 133, Site 112, and Site 85 North

5.1 Project Approach

5.1.1 Initial Approach An Approach Document was developed that outlined the general methodology that was to be used in evaluating the soil and risks associated with the contaminant concentrations at the sites. The approach document was submitted to USARAK, USAED Center of Expertise (CX), EPA, and ADEC for review and comment. Comments were received as follows

• ADEC (August 9, 2000) Letter to USAED; Review of Approach Document Soil Screening Fort Greely BRAC Site 85 South, Site 133, Site 112, Site 85 North.

• EPA (August 23, 2000) Letter to USAED; EPA Comments on the Corps of Engineers Draft Approach Document Soil Screening Fort Greely BRAC: Site 85 South, Site 133, Site 112, and Site 85 North dated July 2000.

• USAED CX (08/11/2000) Submittal No. 005954 67190; Review Comments.

5.1.2 Current Approach As work progressed on the site evaluations, managerial and institutional changes shifted the approach of the study. The EPA Soil Screening Guidance was initially used as the general guide in conducting the work. Change shifted the focus to meet ADEC cleanup levels and risk assessment procedures. This shift in focus came about as a result of discussions between members of the BCT, which included the EPA and ADEC.

It is recognized that the ADEC Method Three/Four risk analysis approaches are protective and compatible with the EPA methodology. Therefore, the soil data are not reviewed against EPA PRGs and RBCs.

The ADEC methods use the same equations as the EPA Soil Screening Guidance. Differences between the two methods include:

• ADEC modified the dilution and attenuation factor (DAF) from 1 to 13.3 [dilution factor = 3.3, attenuation factor = 10];

• ADEC modified exposure frequency from 350 days to 270 days per year (duration remained at the default);

• ADEC modified the risk factor from 10-6 to 10-5; and

• ADEC modified Q/C in the volatilization factor from 68.81 to 90.80.

Results of preliminary evaluation were discussed with representatives of EPA, ADEC, and USARAK during the 20 June 2000 Fort Greely BRAC meeting. Based on this discussion, it was anticipated that the ADEC would require institutional controls for industrial/commercial use, as opposed to allowing an increase to the target risk to 10-4 for residential use.


As previously stated, additional recent changes have occurred which further modify the approach of the work. The subject parcels are now to remain in DOD inventory. These institutional changes occurred when the BRAC portions of Fort Greely were designated as areas potentially needed for future Department of Defense purposes. This change was important, because it is more supportive of an industrial/commercial future land use scenario. Accordingly, the residential scenarios (previously evaluated) are no longer included in this evaluation. However, the residential risk calculations are included in Appendix D.

5.2 Data Assembly and Review Available information specific to each site was assembled and reviewed. The data set for each site was evaluated and a validated data set was developed. In some cases analytes were not detected, but the detection limit was above an ADEC criteria or no ADEC criteria was available. In some of these instances a hypothetical contaminant value was carried forward through the evaluation process. These cases are discussed in more detail in the specific-site sections.

5.3 Soil Evaluation and Risk Assessment A preliminary human health conceptual site model (CSM) was developed for each site and potentially complete pathways were identified to assist in guiding the evaluation. The data set was compared to applicable criteria, and ACL calculations and risk assessments were conducted. In each Site Section, a CSM and the data set are presented along with the ACLs and risk values. The following sections provided more detail on the evaluation procedures.

5.3.1 Screening With ADEC Method Two Cleanup Levels The validated data set from each site was initially screened against ADEC Method Two criteria found in 18 AAC 75.341, Table B1 and Table B2. These criteria reflect region-specific information for three pathways. Any analyte that equaled or exceeded any one of the Method Two criteria was carried forward in the evaluation process. Other analytes that were retained were those without ADEC Cleanup Levels.

In a limited number of instances analytes were dropped from the evaluation process. Each of these cases is discussed in the site sections.

5.3.2 ACLs determined by the ADEC Method Three Calculator The retained analytes (and site-specific soil and aquifer parameters) were input into the ADEC Method Three Calculator and ACLs (Step 4) were calculated. Site-specific inputs (for all sites) are described below.

• The site-specific hydraulic gradient is similar to the regulatory default hydraulic gradient. The default value of 0.002 m/m was used.

• Based on available information a hydraulic conductivity of 30,000 m/yr was calculated and used in the evaluations.

• The reported groundwater recharge rate is approximately 1 inch/year (0.025 meter/year) (USAED 1999). ADEC supports using a value of 20 percent of the average annual precipitation for infiltration rate. Twenty percent of the annual precipitation (11.67 inches/year) or 2.33 inches/year (0.06 meter/year) was used in the calculations.


• A site-specific soil moisture content of 5 percent was used.

• Water-filled Soil Porosity and Air-filled Soil Porosity were both modified from the default values. The water-filled Soil Porosity is the product of dry soil bulk density (default:1.5 g/cm3) and (site-specific) average soil moisture content of 5 percent. A water-filled soil porosity of 0.075 was used. The air-filled soil porosity is the difference between the total soil porosity (default:0.434) and the (site-specific) water-filled soil porosity of 0.075. A value of 0.359 was used.

• Although an aquifer thickness of 40 meters is supported (see Section 4.1), because of concerns raised by ADEC and EPA regarding the leachability modeling at other Fort Greely sites and the concerns about increasing the mixing zone thickness by increasing aquifer thickness, the regulatory default input of 10 meters was used.

• Maximum analyte concentrations were used instead of mean or 95%UCL values, consistent with the ADEC Method Three calculator instructions.

ACLs were calculated for the ingestion, inhalation and migration to groundwater pathways by using site-specific input in the ADEC Method Three calculator. ADEC allows for the modification of ingestion or inhalation cleanup levels under the industrial/commercial land use scenario if this scenario is agreed upon and implemented. As discussed previously, the industrial/commercial scenario has been discussed and agreed upon, and was therefore carried forward. Note that formal methods of tracking sites and implementing the institutional controls at Fort Greely are currently being developed. The resulting ACLs are presented in each of the site-specific sections.

The ADEC Method Three Calculator is available at the following website:

www.dec.state.ak.us/spar/cs/webcalc/

5.3.3 Cumulative Risk determined by the ADEC Method Three Calculator Cumulative industrial cancer risks and hazard indexes are calculated in the final step (Step 5) of the Method Three Calculator. The results of the calculations are discussed in each Site Section.

ADEC methodology requires that analytes detected at one-tenth the cleanup level (for any completed pathway) be included in the calculation of cumulative risk.

5.3.4 Leachability Modeling Leachability modeling was performed by Hart-Crowser, Inc. under subcontract to Jacobs Engineering Group under contract to USAED. The modeling was conducted to evaluate analytes detected at concentrations greater than the migration to groundwater ACLs calculated using the ADEC Method Three calculator. The modeling was conducted using SESOIL with data from the subject sites, where available. Where input data was not available (e.g. soil data from depths greater than the extent of onsite drilling), the modeling used conservative input based on experience from modeling other Fort Greely sites. The purpose of the modeling was to evaluate the potential for contaminants to leach from the soil and impact the groundwater at each site. The results of the modeling are discussed in each site section.


5.3.5 ADEC Method Four Analysis Site 85 North Initial evaluation of Site 85 North using the ADEC Method Three calculator showed a cumulative cancer risk exceeding 1x10-5. As a result, further risk evaluation of Site 85 North was conducted using Method Four procedures. The evaluation of 85 North is considered a “streamlined” risk assessment. Due to the uncomplicated nature of the site and the small area involved, a simplified version of the risk assessment as outlined in ADEC’s “Risk Assessment Procedures Manual” is warranted. This streamlined assessment uses many of the standard default input parameters that are found in ADEC 1999, EPA 2000, and EPA 1996. The site risks are calculated using the equations found in EPA 2000 and ADEC 1999 modified to yield the site risk.

5.4 Report Preparation

This report has been prepared to present the evaluation of contaminants detected in the soil at the four sites. The ACLs and risk calculations (considering an industrial/commercial setting) are presented. The report was prepared in draft format (Revision 0) and submitted to applicable stakeholders for review and comment. The comments received have been incorporated, and this document is now presented as Revision 1.


6.0 SITE 85 SOUTH

6.1 Site Location and Background – Site 85 South

Site 85 South is a former fire training area, and was previously referred to as “GFTP-4A” in documentation prior to BRAC work. Site 85 South is located southeast of the southeast corner of Allen Army Airfield (Figure 1-1). The site is located approximately 1000 feet south of the centerline of the East-West Runway. Photo 6-1 and Photo 6-2 show Site 85 South on 16 August 2000. Figure 6-1 shows the approximate locations of investigation activities that have been conducted at the site.

Based on USAED (1994) Site Assessment/Corrective Action Plan Three Former Fire Training Pits, Fort Greely, Alaska, a rectangular pit was located at the center of the area and drums were stored on the western edge of the fire-training pit according to 1969 aerial photographs.

The following site history summary is based on the AGRA Earth & Environmental, Inc. (AGRA) report titled Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska dated July 1998 (AGRA 1998). The U.S. Army Environmental Hygiene Agency first documented the presence of polynuclear aromatic hydrocarbons (PAH) contamination at the site in 1986. Ecology & Environment, Inc. (E&E) conducted a soil boring program at the site in 1991 and 1992. AGRA collected analytical samples during the installation of bioventing wells in 1994. The results of analytical testing indicated contamination at Site 85 South extended from the surface to 30 feet bgs in the former fire training pit area.

Between 1994 and 1997, AGRA developed and installed an insitu bioventing treatment system at Site 85 South and performed insitu landfarming to a depth of five feet bgs. The bioventing treatment system consisted of four air injection wells, constructed of four-inch diameter PVC pipe with 0.050-inch slot screen installed from five to 25 feet bgs. The wells were fitted with in-line duct fans powered by photovoltaic solar collectors.

Landfarming at Site 85 South consisted of berming the site, tilling soil inside the bermed area, and installing and operating an irrigation system. Tilling was accomplished by digging and backfilling a series of trenches across the site. The trenches, advanced to a depth of approximately five feet bgs, were backfilled with the excavated soil. The irrigation system consisted of piping and a pump that transferred water from Jarvis Creek to the sites. Soil samples were collected from the landfarmed soil intermittently during the treatment process.

After two years of operating and monitoring the treatment system, AGRA concluded that, based on the results of respiration tests (oxygen and carbon dioxide), the bioventing wells were successful at aerating the subsurface soil and biologic activity was occurring. AGRA also concluded the data did not support further operation of the remediation system, and recommended collecting confirmation samples for site closure.

Sampling was conducted at Site 85 South during 1998 under the BRAC LRI program. This work included conducting an initial site evaluation, drilling soil borings, collecting soil samples, and conducting field screening. The biovent system remains in place at Site 85 South, but is not active.


6.2 Identified Documentation and Past Site Activity– Site 85 South

The following identified documents provide information about Site 85 South. Selected items of supporting documentation are included in Appendix 85S.

1. Woodward Clyde (January 24, 1997) U.S. Army Base Realignment and Closure 95 Program, Environmental Baseline Survey Report, Fort Greely, Alaska.

2. Ecology and Environment, Inc. (August 1992) Fire Training Pits Work Plan, Part 1, Fort Richardson and Fort Greely, Alaska. The document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 85 South is referred to as “GFTP4A”.

3. Ecology and Environment, Inc. (August 1992) Fire Training Pits Work Plan, Part 2, Subsurface Exploration Plan, Fort Richardson and Fort Greely, Alaska. The document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 85 South is referred to as “GFTP4A”.

4. USAED (March 7, 1994) Site Assessment/Corrective Action Plan, Three Former Fire Training Pits, Fort Greely, Alaska. The report documents investigation activities at the site. The report references an investigation by the U.S. Army Environmental Hygiene Agency that included drilling three borings at the subject site and identification of elevated PAH concentrations. The document also presents the results of the investigation work conducted by E&E associated with the 1992 work plans referenced above. The document presents a hazard assessment and a corrective action plan. Section 5 of the document, titled “Soil Cleanup Levels” describes the process and results calculating risk-based screening levels under an industrial/commercial scenario for base/nuetral/acid extractables (BNA), pesticides, and dioxin.

5. USAED (April 1994) Environmental Assessment and Finding of No Significant Impact, Remedial Treatment of Petroleum Contaminated Soils, Fire Training Pits, Fort Greely, Alaska.

6. AGRA Earth & Environmental, Inc. (May 1995) Final Remedial Design Report, Contract No. DACA85-94-D-0011, Fire Burn Pits Treatment System, Fort Greely, Alaska. The report presents a design for performing in-situ bioremediation at the site. The design includes landfarming of near-surface soils, followed by installation of bioventing wells, each with a solar powered low-power blower system.

7. AGRA Earth & Environmental, Inc. (July 1998) Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska. The report summarizes the activities and findings of the design, installation, and operation of the insitu bioremediation treatment system at the site.

8. Jacobs Engineering Group Inc. (April 1999) 1998 Remedial Investigation Report, Fort Greely, Alaska, Final. Section 18.0 of the report presents the methodology and results of additional investigation activities conducted at the site under the BRAC LRI program.


9. Jacobs Engineering Group Inc/Radian International . (August 2000) Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska, Final. Section 3.5.4 of the report summarizes the affect of additional background investigation on COPCs for the site.

6.2.1 Pre-BRAC Investigation Activities E&E conducted sampling in 1991. The work included the following.

• One boring was drilled to 16.5 feet bgs (AP-531). • Soil samples were collected from 4.5-6 feet and 14.5-16.5 feet bgs. • Soil samples were analyzed for VOC, BNA, Fuel Identification, pesticides, PCBs,

dioxin/furan, and metals.

E&E conducted additional sampling at the site in 1992. The work included the following.

• Six borings were drilled (AP-581, AP-582, AP-583, AP-584, AP-596, AP-597). Depths of drilling ranged from 11.5 to 46.5 feet bgs. Total drilling footage was 164.6 feet. Five borings were located in or adjacent to the fire training pit area; AP-597 was a background boring.

• Nine surface samples were collected from the fire training pit area. • Selected soil samples were analyzed for benzene, toluene, ethylbenzene and xylenes

(BTEX), fuel Identification, lead, TCLP lead, pesticides, PCBs, BNA, dioxin/furan.

AGRA designed, installed, operated, and monitored an insitu treatment system at the site from 1994 through 1997. The work included the following.

• Eight soil borings were drilled for installation of the system components (BW, A-B1, A-MP-1, A-MP-2, A-MP-3, A-B2, A-B3, A-B4). Total drilling footage was 251 feet.

• The upper five feet of impacted soil in the former fire training pit area was landfarmed by trenching, irrigating, turning, and backfilling. Three bioventing wells with integral blowers were installed and operated. Respirometry was conducted intermittently during system operation.

• Soil samples were collected from the site during system installation and intermittently during operation and monitoring of the soil treatment system.

• Selected soil samples were analyzed for DRO, GRO, BTEX, PAH, pesticides, and bio-treatability parameters.

6.2.2 1997 Investigation Activities

Activities were not conducted at the site during 1997 BRAC efforts.

6.2.3 1998 Investigation Activities

JEG drilled and sampled the site in 1998. The work included the following.

• Six soil borings were drilled (AP-914, AP-917, AP-918, AP-919, AP-920, AP-921). Total drilling footage was 173 feet. One boring was inside the former area of the fire-training pit. Remaining borings surrounded the former pit area.


• Selected soil samples were analyzed for DRO, RRO, GRO, VOC, SVOC, pesticides, PCBs, metals, dioxins, furans, TEQ, TOC, HPC, ODB.

6.2.4 1999 Investigation Activities Activities were not conducted at the site during 1999 BRAC efforts.

6.3 Potential Contaminants

Potential contaminants were identified based on the former use of the site and results of initial investigation activities. The analytical program for samples collected from the site during the history of site investigation has included analysis for:

• POL organic ranges – GRO, DRO, RRO [fuels used during fire training];

• VOCs [constituents of fuels used during fire training];

• SVOCs [constituents of fuels used during fire training];

• Pesticides [possible compounds mixed in fuels used during fire training];

• PCBs [possible compounds contained in fuels used during fire training i.e. old transformer oil];

• Metals [possible compounds contained in fuels used during fire training– i.e. used oil]; and

• Dioxins/furans [possible combustion products from compounds contained in fuels used during fire training].

6.4 Synopsis of Contaminant Distribution – Site 85 South

6.4.1 Pre-Remedial Action This description is based on the findings of work conducted prior to, and in the early part of, remedial action work (work by E&E and AGRA through May 1996).

Contaminants were detected in samples collected from the surface and subsurface in the area inside and immediately surrounding the fire-training area. The following contaminant types were detected at concentrations exceeding regulatory criteria in effect at the time of the work:

• POL fuels (Bunker C, Kerosene, DRO); Detected in surface samples. Detected in subsurface samples to 32 feet bgs.

• BNAs (generally PAH compounds); Detected in surface samples. Detected in subsurface samples to 36.5 feet bgs.

• BTEX compounds (benzene, toluene ethylbenzene, xylenes); Detected in subsurface samples to 11.5 feet bgs.

Contaminant distribution was generally consistent with what would be expected at a site used for fire training. Soils in the upper 10 feet appeared more highly contaminated than deeper soils


between 10 and 36.5 feet bgs. The lateral area of impact appeared consistent with the indicated area used for fire training.

6.4.2 Late and Post Remedial Action Descriptions of analytical results from activities conducted during late remedial action and BRAC activity (work after May 1996 by AGRA and JEG) are provided in the reporting documents associated with those activities. A summary follows.

Contaminants were detected in samples collected from the surface and subsurface in the area inside and immediately surrounding the fire training area. The following contaminant types were detected at concentrations exceeding regulatory levels at the time of the work:

• POL fuels (GRO, DRO); Detected in near-surface samples. Detected in subsurface samples to 22 feet bgs. In general, DRO concentrations appeared lower, on average, than those reported prior to remedial action.

• PAH compounds; Detected in near-surface samples. Detected in subsurface samples to 22.5 feet bgs.

• Volatile organic compounds; Detected in near-surface samples.

• Metals; Although some chromium and iron concentrations exceeded regulatory levels, the concentrations were determined to be within background metal ranges, and are not considered to represent metals contamination.

Again, contaminant distribution was generally as would be expected at a site used for fire training. POL concentrations in the upper 12 feet were greater than concentrations in deeper samples. PAH concentrations decreased with depth. The lateral area of impact appeared consistent with the indicated area used for fire training.

6.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 85 South

A pre-evaluation human health conceptual site model is described below. This description reflects conditions and pathways prior to conducting the ADEC Method Three evaluation. The results of the ADEC Method Three evaluation modify the conceptual site model to that described in Section 6.11.

6.5.1 Contamination Source(s) The contamination source is impacted soil. Surface water does not exist on site. Groundwater is is estimated to exist approximately 170 feet below the ground surface.

The following substances have been detected at the site:

• Petroleum (GRO, DRO, RRO); • Volatile organic compounds; • Semivolatile organic compounds (including PAHs); • Pesticides;


• Dioxin (TEQ); and • Metals.

Based on background sampling conducted under the BRAC program, metals concentrations are attributed to background levels.

6.5.2 Release Mechanism(s) Evaluation of potential release mechanisms follows.

Migration to Subsurface Soil: [Potentially complete]. There are no site improvements/features, other than natural soil conditions, to prevent downward migration.

Soil Transport Via Erosion and Dispersion: [Incomplete]. The impacted area is flat and grass-covered. See Photos 6-1 and 6-2. The area is surrounded on west, south, and east by vegetated ground that slopes upward away from the area.

Migration to Groundwater and Groundwater Transport: [Potentially complete]. Some analyte concentrations exceed published migration to groundwater criteria. Migration to groundwater and groundwater transport are considered “potentially complete” exposure pathways for evaluation under this project.

Runoff to Surface Water or Surface Sediment, Surface Water Transport: [Incomplete]. The nearest surface water feature is Jarvis Creek (approximately 1200 feet to the east). Based on site reconnaissance, drainage channels flow east from the site and end prior to reaching Jarvis Creek. Area run-off from the site infiltrates prior to reaching Jarvis Creek.

6.5.3 Migration Pathways Recognized potential migration pathways consist of:

• Uptake by plants/vegetative cover; • Volatilization to atmosphere (note that enclosed structure(s) do not currently exist

near the contaminated area at the site); • Excavation (potential future activity); • Fugitive dust via contaminant dispersion (note the contaminated area is currently

vegetated, however future site work could remove or disturb vegetation); and • Groundwater movement (if contaminant reached groundwater).

6.5.4 Exposure Routes Potential exposure routes include:

• Ingestion (direct ingestion of soil, groundwater, and fugitive dust); • Dermal contact (dermal/ocular contact with soil during potential future site activity); • Inhalation of volatiles (volatilization of contaminants from near-surface or excavated

soil, or pumped groundwater).


6.5.5 Potential Receptors Currently there are no residents or workers on site. Residential use of the site is not anticipated in the future and is not considered. The site is immediately adjacent to an active taxiway and runway and inside a restricted airspace zone.

• On-site: Due to the recent changes in the expected future land use, residential use is ruled out at this time for purposes of this evaluation. Thus, only the on-site future worker scenario remains in the CSM for consideration.

• Off-site: Groundwater flows northeast, away from the main cantonment. Although people currently reside and work at other locations at Fort Greely, there are no current stationary facilities located down-gradient of the site between the site and Jarvis Creek. However, due to uncertainty in future base development, ingestion, dermal contact, and/or inhalation of volatiles from potentially impacted groundwater, which could potentially be pumped from on-site or offsite wells for residential or worker use, remains a part of this evaluation.

Subsistence use of the site area and impact to site visitors are not considered realistic scenarios due to site conditions and the site’s proximity to an active taxiway and runway.

6.6 Data Set

6.6.1 Data Sources Table 6-1 presents the data used in the soil evaluation process, and includes compounds (parameters), units, detection frequency, reported concentrations, minimum and maximum reported concentrations, detection limits, and background concentrations for the parameters.

Figure 6-1 is a sample location map. The area of the clearing that includes and surrounds the bermed former fire-training pit is roughly 140 feet by 160 feet, or approximately 0.5 acre. All samples used in the soil evaluation data set were from this area. The former fire-training pit itself was approximately 50 feet by 110 feet (per AGRA 1998) (approximately 5,500 ft2, or about 0.13 acre).

Bioventing was conducted at the site from 1994 through 1997 to treat subsurface impacted soils. Landfarming was also conducted to treat near-surface (upper four to five feet) impacted soils in the former fire training pit area. Because a remediation program was conducted at the site, pre-remediation data for POL analytes (GRO, DRO, RRO, PAH, and BTEX compounds) was not included in the evaluation. Only post-remediation data and data collected late in the remediation process for POLs were included in the screening.

The POL analyte data set consists of:

• 1996 and 1997 analytical results from AGRA work involving monitoring of near-surface landfarmed soil in the former fire training pit area; and

• 1998 analytical results from JEG BRAC activity.


Pre-remediation data was used for pesticides, PCBs, dioxins, and metals. These compounds are expected to be less subject to biodegradation as a result of the remediation activity than the POL compounds. Additionally, utilization of pre-remediation results increases the size of the data set and adds conservatism to the evaluation by capturing elevated concentrations identified prior to the remediation program.

6.6.2 Review of Data Set Detection Limits To arrive at the valid data set for this site, the detection limits were compared to ADEC Method Two limits. Where none existed the detection limits were compare to other ADEC or EPA criteria. In most cases the detection limits reported by the laboratories were less than any ADEC or EPA reporting criteria. There were select cases were this was not true. The exceptions are discussed below.

Volatile Organic Compounds (VOCs)

Benzene: The data set includes only post-remediation data from 1998 and 1996 – 1997. The 1998 results yielded three detections of benzene. The detection limit was 0.05 mg/kg. The ADEC Method Two level for migration to groundwater is 0.02 mg/kg. In 1996-1997, benzene was also detected at a maximum level of 0.0942 mg/kg with a detection limit below 0.02 mg/kg. Because benzene from the 1996-97 analysis was detected at a higher level (0.0942 mg/kg) than the detection limit from 1998 analysis (0.05 mg/kg), the maximum concentration of 0.0942 mg/kg is used in the subsequent calculations.

Sec-Butylbenzene, Tert-Butylbenzene, cis-1,2-Dichloroethene, Isopropylbenzene (cumene), n-Propylbenzene, 1,2,4-Trimethylbenzene, 1,3,5-Trimethylbenzene: For these analytes, there are no ADEC Method Two criteria. All had detection limits ranging from 0.05 mg/kg to 0.2 mg/kg. All of these detection limits are below the EPA Region 9 PRGs or ADEC Technical Memorandum cleanup values. Therefore, the reported non-detections are considered valid.

Tetrachloroethylene (PCE): The ADEC Method Two level for PCE is 0.03 mg/kg. The detection limit for this compound was 0.05 mg/kg. The analyte was detected at 0.09 mg/kg and 0.03 mg/kg. For purposes of calculating the risk, the maximum detected value (0.09 mg/kg) is used.

4-Isopropyltoluene (cymene): The detection limit was 0.2 mg/kg. Using Isopropylbenzene as a surrogate, the detection limit is below cleanup values. The reported non-detects are considered valid.

Semi-Volatile Organic Compounds (SVOCs)

SVOCs were sampled for in 1998 and in 1996-1997. Detection limits for nearly all of the parameters were below the ADEC Method Two limits.

Dibenz(a,h)anthracene: The one exception was dibenz(a,h)anthracene, which has an ADEC level of 1 mg/kg. One reported non-detect had a detection limit of 1.5 mg/kg (the others ranged from 0.01 mg/kg to 0.3 mg/kg). The data from 1996 – 1997 sampling only includes the


maximum concentration for samples where there is a primary quality assurance and quality control sample.

Nitrophenol: For the one SVOC analyte without an ADEC level (nitrophenol), the detection limit was below the EPA Region 9 PRGs level.

Pesticides/Insecticides/PCBs

Aldrin: The ADEC Method Two level is 0.50 mg/kg. The detection limit for most samples ranged from 0.004 mg/kg to 0.13 mg/kg. Six samples in 1992 had detection limits near 0.7 mg/kg. However, because the maximum detection at this site was 0.0072 mg/kg and there are over 100 samples with valid non-detects, it can be concluded that all the reported non-detections were valid.

Alpha-Hexachlorocyclohexane (a-HCH): The ADEC Method Two level for a-HCH is 0.0026 mg/kg. The detection limit from the 1998 analysis was 0.01 mg/kg. However, this compound was detected at 0.007 mg/kg. Also, at Site 133, using the same analytical method and detection limit, it was detected as low as 0.002 mg/kg. Therefore, if the analyte were to be present at this site at a level of 0.02 mg/kg, it should have been detected and reported. Considering this, it was determined that all of the non-detections are valid and the concentration used in the calculations will be 0.007 mg/kg.

Endrin: The ADEC Method Two level for Endrin is 0.3 mg/kg. Most analysis had detection limits ranging from 0.0005 mg/kg to 0.0176 mg/kg. Seven samples (out of over 100 total samples) in 1992 had detection limits that exceeded the ADEC level. One had a detection limit of 0.32 mg/kg and six had detection limits ranging from 1.6 mg/kg to 1.7 mg/kg. Detection limits above the ADEC criteria account for less than 10 percent of the total analysis. It is concluded that the reported non-detects are valid.

Heptachlor Epoxide: The ADEC Method Two level is 0.2 mg/kg. Most sampling results had detection limits ranging from 0.0005 mg/kg to 0.13 mg/kg. Seven analyses (out of over 100 total) in 1992 had detection limits that exceeded the ADEC level. One had a detection limit of 0.32 mg/kg and six had detection limits ranging from 1.6 mg/kg to 1.7 mg/kg. Detection limits above the ADEC levels account for less than 10 percent of the total analyses. It is concluded that the reported non-detects are valid.

Dieldrin: The ADEC Method Two criteria is 0.015 mg/kg. The analysis in 1991, and some in 1992, yielded detection limits that exceeded the ADEC value. However, since 1994, results from approximately 90 analyses had a detection limit of 0.01 mg/kg or lower (with the exception of one sample with a detection limit of 0.0176 mg/kg). Based on the large amount of sampling and that dieldrin was only detected in two samples at very low levels of 0.0019 mg/kg and 0.0032 mg/kg, it was concluded that the reported non-detections are valid.

Metals: All reported non-detections for metal analysis had detection limits below the ADEC Method Two levels with the exception of the 1991 analysis for antimony. The detection limit was 12.0 mg/kg. However, analysis in 1998 yielded a detection limit of 1 mg/kg with several detections ranging from .5 mg/kg to 1.0 mg/kg. It was concluded that these detections represent the highest concentrations at the site.


6.7 ADEC Method Two Criteria

6.7.1 Initial Screening Process Table 6-2 lists the ADEC Method Two soil cleanup levels from 18 AAC 75.341 Table B1 and Table B2. For each analyte detected, Table 6-2 shows the frequency that the analyte was detected at a concentration that exceeds an ADEC Method Two cleanup level. Where an ADEC Method Two cleanup level was exceeded, the table indicates the specific exposure pathway associated with that level. Those analytes without ADEC cleanup criteria are also noted. The table is summarized below.

The ADEC Method Two cleanup levels for the following analytes (applicable exposure pathway is indicated in parenthesis) were exceeded:

• benzene (migration to groundwater); • benzo(a)pyrene (ingestion, migration to groundwater); • alpha-Hexachlorocyclohexane (HCH-a) (migration to groundwater); • tetrachloroethylene (PCE) (migration to groundwater); • 1,3,5-trimethylbenzene (migration to groundwater); • gasoline range organics (GRO) (migration to groundwater); • diesel range organics (DRO) (migration to groundwater); • arsenic (ingestion, migration to groundwater); and • chromium (migration to groundwater).

Detected parameters without Method Two Criteria (Table B-1 or B-2) include:

• sec-butylbenzene; • tert-butylbenzene; • cis-1,2-dichloroethene; • 4-isopropyltoluene (cymene); • n-propylbenzene; • 4-nitrophenol; • dioxins, (listed in Table B-1, but has no pathway specific cleanup levels); and • lead (listed in Table B-1, but has no pathway specific cleanup levels).

6.7.2 Elimination of Analytes Analytes were eliminated for further consideration for two reasons:

• either the detected concentration represents natural background levels, therefore it should not be considered a contaminant at this site; or

• insufficient data are available to properly evaluate the compound.

Arsenic and chromium were eliminated because the results indicate that the detected concentrations are background levels. The detected arsenic concentration ranged from 2 mg/kg to 21 mg/kg. The results from the background analysis ranged from 4 mg/kg to 40 mg/kg. Chromium results ranged from 10 mg/kg to 47 mg/kg, whereas the background analysis yielded results that ranged from 8 mg/kg to 43 mg/kg. Statistical analysis of chromium described in the


1999 Summary Report (Jacobs, August 2000) indicates chromium detections are within acceptable background parameters.

The only other analyte that was eliminated from further evaluation was 4-isopropyltoluene (cymene). There are not sufficient data to evaluate this compound. The chemical is also referred to as isopropyltoluene or methylisopropylbenzene. The Merck Index number is 2832; the CASRN is 25155-15-1. EPA Region 9 PRGs and EPA Region 3 RCBs are not available for this compound. Furthermore there is no information on the IRIS web-site. Chemical input information was not available from the ADEC. Therefore this compound was not included in the subsequent risk calculations.

6.7.3 Findings of Initial Screening The following findings are noted.

1. Seven of 45 benzene results exceeded the ADEC Method Two migration to groundwater level.

2. Ten of 29 benzo(a)pyrene results exceeded the ADEC Method Two ingestion level. Three of the 29 results in the data set exceeded the ADEC Method Two migration to groundwater level.

3. One result of 1,3,5 trimethylbenzene equaled the ADEC Method Two level of 25 mg/kg.

4. One of 122 alpha-hexachlorocyclohexane results exceeded the ADEC Method Two migration to groundwater level.

5. One of 17 tetrachloroethylene results exceeded the ADEC Method Two migration to groundwater level.

6. Two of 38 samples contained GRO at concentrations exceeding ADEC Method Two criteria for migration to groundwater.

7. Thirty of 42 samples contained DRO at concentrations exceeding ADEC Method Two criteria for migration to groundwater.

6.8 Alternative Cleanup Levels

Alternative soil cleanup levels (ACLs), for an industrial/commercial scenario were developed for applicable pathways using the ADEC Method Three Calculator. These ACLs are shown on Table 6-3 and on ADEC Method Three documentation attached at the end of this section.

The following findings are noted.

1. Three of 42 DRO results (4800 mg/kg, 4200 mg/kg, and 3700 mg/kg) exceeded the calculated ACL (3300 mg/kg) for migration to groundwater.

2. The cleanup level for lead in an industrial scenario is 1000 mg/kg. The highest detected value was 130 mg/kg.

3. Dioxin has no ACL. The cleanup level for dioxin is set on a case by case basis. The highest detected concentration of dioxin was 1.17x10-6 mg/kg.


6.9 Cumulative Risk

Analytes that were detected at one-tenth or greater of an ADEC Method Two cleanup level (smallest value) were included in the cumulative risk calculations. Analytes that do not have an ADEC Method Two cleanup level were also included. The data set is shown on Table 6-2. GRO, DRO, and RRO are not included in the cumulative risk calculations per ADEC methodology.

Calculations resulted in a cumulative industrial cancer risk of 8.9x10-6 and non-cancer industrial hazard index of 0.76. The ADEC Method Three documentation sheets are attached at the end of this section.

6.10 Leachability Modeling

Detected DRO concentrations exceed the calculated site-specific ACL for the migration to groundwater pathway developed using the ADEC web-based calculator. However, the equations used in the calculator do not incorporate the depth to groundwater beneath the contaminated soil.

As a result, leachability modeling was conducted using SESOIL to further evaluate the potential for DRO migration to groundwater. A memorandum describing the procedures and results is provided at the end of this section. The results of the modeling indicated that the DRO contamination would not impact the groundwater at Site 85S.

6.11 Complete Exposure Pathways

Figure 6-2 illustrates the complete exposure pathways and the human health conceptual site model after conducting the evaluation.

Onsite

There are no current complete exposure pathways onsite. Under future industrial/commercial land use, the following exposure pathways are considered complete:

• ingestion of soil by workers; and • dermal contact with soil by workers.

Inhalation of volatile organic compounds associated with near-surface impacted soil is considered incomplete because near-surface soil at this site has undergone landfarming.

Migration to groundwater is considered incomplete as a result of the ADEC Method Three calculator run and the leachability modeling conducted.

For the complete pathways listed, none of the analytes exceed the ADEC Method Three derived cleanup levels for those pathways.

Offsite

The area down-gradient (groundwater) is not currently occupied by residents or workers. The ADEC Method Three calculator and leachability modeling showed that the soil contamination


would not impact groundwater at the site. Under industrial/commercial land use there are no complete off-site pathways.

6.12 Recommendations – Site 85 South

The following recommendations are based on the results of the process described above.

1. Implementation of institutional controls for industrial/commercial land use is recommended. Controls should include provisions to prevent moving contaminated soil offsite. Additionally, controls should include provisions to prevent drilling a water production well through the contaminated soil.

2. No further active remedial action is recommended for Site 85 South.

3. The biovent wells and monitoring points from the existing remediation system should be decommissioned.

AP−533

Site: Site 85 South Photograph Date: 16 August 2000 Description: Looking northwest from inside bermed former burn pit area. Photo shows existing biovent wells and solar panels.

Biovent well

Solar Panel

Taxiway Tarmac

Photo6-1

SITE 85 SOUTH PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

11 OCTOBER 2000

REVISIONS:

Site: Site 85 South Photograph Date: 16 August 2000 Description: Looking southeast at bermed former burn pit with existing biovent wells. Berm is shown in foreground.

Berm

Biovent Well

Photo6-2

SITE 85 SOUTH PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

11 OCTOBER 2000

REVISIONS:

TABLE 6-1DATA SET, SITE 85 SOUTH, FORT GREELY, ALASKA

Parameter Units Detection

Frequency Reported Concentrations *1Minimum Reported

ConcentrationMaximum Reported

Concentration

Reporting Limits (varies by sample) *2

Background Concentration

PETROLEUM HYDROCARBONS (FUELS)Gasoline Range Organics (GRO) mg/kg 27 / 38 Not Detected (ND), ND, 1.1, ND, ND, 5.1J, ND,

ND, ND, ND, ND, ND, 6.3J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

1 700 <1 - 5.0

Diesel Range Organics (DRO) mg/kg 38 / 42 3100, 4200, 2600, 2700, 2600, 2900, 1100, 530, 759, 360, 1000, 1300, 1200, 1200, 1300, 700, 1300, 1300, 2200, 1600, 2300, 1700, 1900, 1800, 3700, 730, 4800, 660, 35, 820, 7, 10, ND, 4, ND, ND, 1130, 6, 9, ND, ND, ND

4 4800 4 - 11 <68 *3

Residual Range Organics (RRO) mg/kg 8 / 17 830, 3500, 690, ND, 550, ND, ND, ND, 30, ND, ND, 2730, 30, 50, ND, ND, ND

30 3500 21 - 100

VOLATILESBenzene mg/kg 9 / 45 ND, ND, 0.0942J, 0.051, 0.087, ND, 0.014, ND,

ND, 0.034, 0.017J, ND, ND, 0.007, ND, ND, ND, 0.055, ND, ND, 0.036, 0.04J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

0.007 0.0942 J 0.009 - 0.05

Toluene mg/kg 15 / 38 ND, ND, 0.627, 0.280, 0.370, ND, 0.075, ND, ND, 0.250, 0.099, ND, ND, 0.036, ND, 0.130, 0.120, 0.250, 0.062, ND, 0.260, .44J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, 0.07, ND, ND, ND, ND, ND

0.062 0.627 0.02 - 0.05 ND - 0.08 *3

Ethylbenzene mg/kg 6 / 38 ND, ND, 0.038, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, 0.013, ND, 0.21, ND, ND, ND, ND, 0.098, 0.07J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, 0.25, ND, ND, ND, ND, ND

0.013 0.25 0.017 - 0.05

Table 1s R1.xls, 85s Page 1 of 10





Concentration



Xylenes (total) mg/kg 21 / 38 8.1, 4.7, 2.63, 2.4, 13, 2.2, 0.74, ND, 0.59, 0.14, 0.11J, ND, 0.21, 0.079, 4.8, 1.0, 1.7, 1.3, 5.7, 3.0, 1.28, 3, 0.33J, ND, ND, ND, 0.04, ND, ND, ND, ND, ND, 4.5, ND, ND, ND, ND, ND

0.079 13 0.05 - 0.096

Sec-Butylbenzene mg/kg 1 / 17 0.3, (16)ND 0.3 0.3 0.04 - 0.2Tert-Butylbenzene mg/kg 2 / 17 0.1, 0.3, 15 ND 0.05 0.1 <0.05 - 0.2Carbon Tetrachloride mg/kgChlorobenzene mg/kgChloroform mg/kg1,2-Dibromoethane mg/kg1,2-Dichloroethane (EDC) mg/kgcis-1,2-Dichloroethene mg/kg 1 / 17 0.06, 16 ND 0.06 0.06 0.05Cis-1,2-Dichloroethane mg/kg1,1-Dichloroethylene mg/kgn-Hexane mg/kgIsopropylbenzene (cumene) mg/kg 1 / 17 0.21, 16 ND 0.21 0.21 0.24-Isopropyltoluene (cymene) mg/kg 2 / 17 0.09, 0.89, 15 ND 0.09 0.89 0.2Methylene chloride mg/kgMethyl ethyl ketone mg/kgMTBE (Tert-butyl methyl ether) mg/kgn-Propylbenzene mg/kg 1 / 17 0.4, 16 ND 0.4 0.4 0.21,1,2,2-Tetrachloroethane mg/kgTetrachloroethylene (PCE) mg/kg 2 / 17 0.09J, 0.03J, 15 @ ND 0.03 J 0.09 J 0.21,1,1-Trichloroethane mg/kgTrichloroethene (TCE) mg/kgTrichlorofluoromethane mg/kg1,2,4-Trimethylbenzene mg/kg 5 / 17 0.48, 0.2, ND, ND, ND, 0.1, 0.2, ND, ND, ND,

ND, 6.3, ND, ND, ND, ND, ND0.1 6.3 0.2

1,3,5-Trimethylbenzene mg/kg 5 / 17 1.9, 25, ND, ND, ND, 0.04, 0.05, ND, ND, ND, ND, 3.4, ND, ND, ND, ND, ND

0.04 25 0.2

Vinyl Chloride mg/kg






Concentration



SEMIVOLATILESAcenaphthene mg/kg 13 / 29 0.130, 0.160, 0.160, 0.250, 0.260, 0.100, 0.130,

0.060, 0.051, 0.047, ND, 0.3, 0.3J, 0.5J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

0.047 0.5 J 0.037 - 0.3

Anthracene mg/kg 7 / 29 ND, 0.063, 0.059, 0.055, 0.063, 0.043, 0.085, ND, ND, ND, ND, ND, 0.3J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

0.043 0.3 J 0.034 - 1.5

Benzo(a)anthracene mg/kg 16 / 29 0.47, 1.25, 0.95, 0.92, 1.4, 0.7, 2.4, 0.4, 0.26, 0.35, 0.24, 0.52, 2.4, 0.2J, ND, ND, ND, ND, ND, ND, 0.1, 0.1, ND, ND, ND, ND, ND, ND, ND

0.2 2.4 0.3

Benzo(k)fluoranthene mg/kg 14 / 29 0.420, 0.280, 0.580, ND, 1.2, 0.46, 1.3, ND, 0.260, 0.190, 0.190, ND, 2.2, 0.2, ND, ND, 0.08, ND, ND, ND, 0.2, 0.2, ND, ND, ND, ND, ND, ND, ND,

0.19 2.2 0.3

Benzo(b)fluoranthene mg/kg 17 / 29 1.65, 2.12, 2.49, 2.60, 2.8, 1.4, 4.4, 1.4, 0.57, 0.65, 0.85, 1.8, 3.2, 0.3, ND, ND, 0.08, ND, ND, ND, 0.2, 0.2, ND, ND, ND, ND, ND, ND, ND,

0.08 4.4 0.3

Benzo(a)pyrene mg/kg 20 / 29 1.2, 2.1, 2.4, 2.6, 3.1, 1.9, 5.1, 1.4, 0.46, 0.54, 0.63, 0.50, 0.93, 1.9, 3.9, 0.3, 0.1, ND, 0.08, ND, ND, ND, 0.3, 0.3, ND, ND, ND, ND, ND, ND, ND

0.08 5.1 0.3

Benzo(g,h,i)perylene mg/kg 17 / 29 0.790, 1.03, 0.221, 1.6, 2.1, 1.3, ND, 1.2, 0.410, 0.550, 0.610, 1.4, 2.4, 0.3, 0.08, ND, 0.1, ND, ND, ND, 0.1, 0.1, ND, ND, ND, ND, ND, ND, ND

0.08 2.4 0.014 - 0.3

Benzoic Acid mg/kgBenzyl Alcohol mg/kgBis(2-ethylhexyl)phthalate (DEHP) mg/kg 4 / 17 0.1, 0.7, 0.1, 0.1, 13 ND 0.1 0.7 0.3Butylbenzylphthalate mg/kgCarbazole mg/kg






Concentration



Chrysene mg/kg 16 / 29 0.75, 0.86, 0.95, 1.1, 1.7, 0.6, 2.5, 0.46, 0.28, 0.34, 0.33, 0.53, 3.2, 0.3, ND, ND,ND, ND, ND, ND, 0.2, 0.2, ND, ND, ND, ND, ND, ND, ND

0.28 3.2 0.3

Cresol (total) mg/kgDibenzofuran mg/kg 1 / 17 0.2 0.2 0.3Dibenz(a,h)anthracene mg/kg 12 / 29 0.203, 0.430, 0.628, ND, 0.33, 0.77, ND, 0.16, ND,

0.24, ND, ND, 0.6, ND, ND, ND, 0.05, ND, ND, ND, 0.03, 0.03, ND, ND, ND, ND, ND, ND, ND

0.03 0.77 0.01-0.3, 1 at 1.5

1,4-Dichlorobenzene mg/kgDimethylphthalate mg/kg2,4-Dinitrotoluene mg/kgFluoranthene mg/kg 16 / 29 0.61, 0.85, 0.84, 1.1, 1.6, 0.57, 2.4, 0.32, 0.29,

0.37, 0.33, 0.46, 3.4, 0.3, ND, ND, ND, ND, ND, ND, 0.1, 0.1, ND, ND, ND, ND, ND, ND, ND

0.1 3.4 0.3

Fluorene mg/kg 8 / 29 0.17, 0.56, 0.289, ND, ND, ND, ND, 0.11, 0.096, 0.11, 0.09, 0.9, PLUS 16 NDs

0.09 0.9 0.51-0.3

Hexachlorobenzene mg/kgHexachloro-1,3-butadiene mg/kgHexachloroethane mg/kgIndeno(1,2,3,-cd)pyrene mg/kg 18 / 29 0.87, 1.09, 1.3, 1.6, 2.4, 1.2, 2.4, 1.1, 0.42, 0.52,

0.47, 1.4, 2.8, 0.3, 0.07, ND, 0.1, ND, ND, ND, 0.1, 0.1, ND, ND, ND, ND, ND, ND, ND

0.07 2.8 0.3

Isophorone mg/kg2-Methylnaphthalene mg/kg 2 / 17 2.5, 0.8, 15 ND 0.8 2.5 0.3Naphthalene mg/kg 14 / 32 2.7, 0.2, 0.1, 0.32, ND, 0.05, 0.13, ND, ND, 0.24,

ND, 0.21, 0.26J, 0.43J, 0.24, ND, ND, 0.02, 0.03, ND, ND, ND, ND, 1.1, ND, ND, ND, ND, ND

0.02 2.7 0.3

Nitrobenzene mg/kg4-Nitrophenol mg/kg 1 / 17 0.5, 16 ND 0.5 0.5 2.0, 1 at 10Pentachlorophenol mg/kg






Concentration



Phenanthrene mg/kg 14 / 29 0.147, 0.391, 0.27, 0.22, 0.23, 0.12, 0.25, 0.053, 0.068, 0.086, 0.069, 0.12, 1.3, 0.4, PLUS 15@ND

0.053 1.3 0.3

Di-n-butyl phthalate mg/kg 1 / 17 0.2, 16 ND 0.2 0.2 0.3Pyrene mg/kg 16 / 28 0.6, 2.35, 1.58, 0.86, 1.4, 0.55, 2.2, 0.35, 0.27,

0.31, 0.39, 0.55, 4, 0.06, ND, ND, ND, ND, ND, 0.2, 0.2, ND, ND, ND, ND, ND, ND, ND

0.06 4 0.3

Pyridine mg/kg2,4,5 Trichlorophenol mg/kg2,4,6 Trichlorophenol mg/kg

PESTICIDES / INSECTICIDES

Aldrin mg/kg 3 / 122 [1991] 2 @ ND, [1992] 24 @ ND, 6 @ ND(0.7) ; [1994] 0.00058, 26 @ ND, [1995] 2 @ ND, [1996-1997] 0.0013, 0.0072, 43 @ ND, [1998] 17 @ ND

0.00058 0.0072 0.004 - 0.13 except as noted in

"Reported Concentrations

" columnBHC (a) (6) (HCH alpha) mg/kg 1 / 122 [1991] 2 @ ND(0.17); [1992] 6 ND(0.17), 1

ND(0.035), 1 ND(0.007), 1 ND(0.0037)17 @ ND(0.00037 - 0.0007); [1994] 27 @ ND(?), [1995] 2 @ ND(?), [1996-1997] 45 @ ND(?), [1998] 0.007J, 16 @ ND(0.01)

0.007 J 0.007 J See detection limits in


" columnBHC (b) (6) (HCH beta) mg/kgBHC (g) Lindane (6) (HCH gamma) mg/kg

Chlordane mg/kg2,4-D (2,4-Dichlorophenoxyacetic acid)

mg/kg






Concentration



4,4-DDD mg/kg 74 / 122 [1991] ND, ND, [1992] 0.015, 0.1, 0.1, 0.005, 0.098, 0.098, 0.039, 0.12, 0.19, 0.012, 20 @ ND, [1994] ND, 0.0082, 0.0017, 0.012, ND, 0.0037, 0.0026, ND, ND, ND, ND, 0.0065, 0.007, 0.005, ND, ND, ND, 0.0031, 0.0065, 0.037, ND, ND, 0.0033, 0.0013, ND, ND, 0.028, [1995] ND, ND, [1996-1997] 0.065, 0.061, 0.040, 0.087, 0.060, 0.07, 0.051, 0.095, 0.1, 0.095, 0.1, 0.089, 0.035, 0.025, 0.036, 0.045, 0.59, 0.11, 0.13, 0.021, 0.015, 0.009, 0.028, 0.039, 0.027, 0.016, 0.073, 0.027, 0.034, 0.065, 0.063, 0.048, 0.055, 0.036, 0.040, 0.043, 0.030, 0.059, 0.002, 0.033, 0.081, 0.051, 0.028, [1998] 0.096, 0.012, 0.004, ND, 0.031, ND, ND, ND, 0.007, 0.004, ND, ND, ND, 0.005, ND

0.0017 0.59 0.001 - 1.7

4,4-DDE mg/kg 60 / 122 [1991] ND, ND, [1992] 0.033, 29 @ ND, [1994] ND, 0.0034, ND, 0.0057, ND, ND, ND, ND, ND, ND, ND, 0.0033, 0.0034, 0.0028, ND, ND, ND, 0.0012, 0.0032, 0.014, ND, ND, 0.0038, ND, ND, ND, 0.011, [1995] ND, ND, [1996-1997] 0.013, 0.011, ND, 0.019, 0.013, 0.013, 0.0116, 0.014, 0.018,0.015, 0.028, 0.019, 0.0095, 0.0061, 0.008, 0.010, 0.009, 0.032, 0.024, 0.0068, 0.013, 0.017, 0.010, 0.007, 0.011, 0.016, 0.007, 0.0049, 0.019, 0.013, 0.0057, 0.014, 0.013, 0.011, 0.013, 0.0079, 0.0073, 0.0078, 0.0067, 0.014, 0.010, 0.007, 0.017, 0.014, 0.007, [1998] 0.010, 0.002, ND, ND, 0.005, ND, ND, ND, 0.004, ND, ND, ND, ND, 0.005, ND

0.002 0.033 0.001 - 1.7






Concentration



4,4-DDT mg/kg 87 / 122 [1991] ND, ND, [1992] 0.23, 0.037, 0.026, 0.0059, 0.004, 0.2, 0.054, 0.054, 0.0046, 0.18, 0.0051, 0.099, 0.39, 0.012, 0.031, 0.160, 14 @ ND, [1994] 0.0018, 0.0029, 0.0052, 0.0056, 0.0058, 0.0053, 0.0069, 0.0041, 0.0017, 0.0019, 0.0035, ND, 0.0043, 0.0051, ND, ND, 0.002, 0.0013, ND, 0.041, 0.0029, ND, ND, 0.002, ND, ND, 0.030, [1995] ND, ND, [1996-1997] 0.037, 0.026, 0.020, 0.040, 0.042, 0.050, 0.044, 0.13, 0.11, 0.19, 0.079, 0.078, 0.033, 0.028, 0.029, 0.061, 0.046, 0.070, 0.15, 0.091, 0.097, 0.095, 0.060, 0.040, 0.080, 0.071, 0.041, 0.025, 0.14, 0.083, 0.016, 0.055, 0.023, 0.037, 0.071, 0.032, 0.026, 0.034, 0.032, 0.044, 0.028, 0.034, 0.068, 0.033, 0.015, [1998] 0.008, 0.002, 0.002, ND, 0.003, ND, ND, ND, 0.046, 0.018, ND, ND, ND, 0.037, ND

0.0017 0.39 0.001 - 1.7

Endosulfan mg/kg 11 / 122 [1991] ND,ND, [1992] 30 @ ND, [1994] 0.0032, 0.0028, 0.00082, 0.0021, 0.0019, 0.0019, 0.0025, 0.0041, 0.0012, 19 @ ND, [1995] ND, ND, [1996-1997] 0.0036, 0.0012, 43 @ ND [1998] 17 @ ND

0.0012 0.0041 0.003 - 1.7

Endrin mg/kg 4 / 122 [1991] 2 @ ND, [1992] 6 ND(1.6-1.7), 1 ND(0.32), 23 @ ND, [1994] 0.0019, 0.0059, 0.0053, 24 @ ND, [1995] 2 @ ND, [1996-1997] 45 @ ND, [1998] 0.007J, 16 @ ND

0.0019 0.007 0.0005 - 0.0176 except

as noted in "Reported

Concentrations" column

Heptachlor mg/kg






Concentration



Heptachlor Epoxide mg/kg 2 / 122 [1991] 2 @ ND, [1992] 6 ND(1.6-1.7), 1 ND(0.32) , 23 @ ND, [1994] 27 @ ND, [1995] 2 @ ND, [1996-1997] 0.001, 44 @ ND, [1998] 0.002, 16 @ ND

0.001 0.002 0.0005 - 0.13 except as noted in


" columnMethoxychlor mg/kg 4 / 122 [1991] 2 @ ND, [1992] 30 @ ND, [1994] 0.010,

0.0061, 0.0042, 0.0058, 23 @ ND, [1995] 2 @ ND, [1996-1997] 45 @ ND, [1998] 17 @ ND

0.0042 0.010 0.003 - 0.28

Toxaphene mg/kgDieldrin mg/kg 2 / 122 [1991] 2 @ ND(0.034), [1992] 6 ND(1.6-1.7), 1

ND(0.32), 1 ND(0.064), 5 ND(0.032-0.035), 17 @ ND(0.0032), [1994] 27 @ ND(0.01), [1995] 2 @ ND(0.0031), [1996-1997] 0.0019, 0.0032, 1 ND(0.0176), 42@ ND(0.0003-0.0036), [1998] 17 @ ND(0.01)

0.0019 0.0032 See detection limits in


" column

2,4,5-TP (2-(2,4,5-trichlorophenoxy)propionic acid)

mg/kg

POLYCHLORINATED BIPHENYLSAroclor 1016 mg/kgAroclor 1254 mg/kgTotal PCBs mg/kg 0 / 15 ND, ND, ND, ND, ND, ND, ND, ND, ND, ND,

ND, ND, ND, ND, ND0.1






Concentration



DIOXINS/FURANS2,3,7,8 TCDD Equivalent (TEQ) mg/kg 17 / 17 6.31E-07, 6.52E-07, 1.82E-07, 1.27E-07, 9.4E-07,

5.75E-07, 4.51E-07, 4.82E-07, 4.21E-07, 6.45E-07, 3.97E-07, 1.17E-06, 7.47E-07, 6.97E-07, 8.03E-07, 5.73E-07, 9.56E-07

1.27E-07 1.17E-06

METALSRCRA metalsArsenic mg/kg 15 / 15 [1991] 2.5-4.3, [1998] 5-21 5 21 4 - 40 *3

Barium mg/kg 15 / 15 [1991] 74.9-132 [1998] 45-144 45 144 43 - 651 *3

Cadmium mg/kg 2 / 15 [1991] ND(1.0) [1998] 0.6-0.7 0.6 0.7 ND [0.10 - 0.13] *3

Chromium (7) mg/kg 15 / 15 [1991] 10-15.5 [1998] 11-47 10 47 8 - 43 *3

Lead mg/kg 15 / 15 [1991] 8.8-12.6 [1992] 4.2-130 [1998] 4-53 4 130 5 - 69 *3

Mercury mg/kgSelenium mg/kg 2 / 15 [1991] ND(1.0) [1998] 0.8-1 0.8 1 0.3J - ND[1] *3

Silver mg/kgOther metals Aluminum mg/kg 15 / 15 [1991] 5960-11000 [1998] 5370-17200 5,370 17,200 65,000 *4

Antimony mg/kg 12 / 15 [1991] ND(12) [1998] 0.5-1 0.5 1 0.66 *5

Beryllium mg/kg 4 / 15 [1991] ND(1) [1998] 0.1-0.4 0.1 0.4 1.35 *4

Calcium mg/kg 15 / 15 [1991] 2580-5380 [1998] 2380-5460 2380 5460 20,000 *4

Cobalt mg/kg 15 / 15 [1991] 6.2-10 [1998] 4-12 4 12 14 *4

Copper mg/kg 15 / 15 [1991] 27.7-44.7 [1998] 12-38 12 44.7 29 *4

Iron mg/kg 15 / 15 [1991] 14400-18600 [1998] 12600-35300 12600 35300 38000 *4

Magnesium mg/kg 15 / 15 [1991] 4590-5340 [1998] 1970-6630 1970 6630 12000 *4

Manganese mg/kg 15 / 15 [1991] 300-457 [1998] 216-454 216 457 670 *4

Nickel mg/kg 15 / 15 [1991] 22.2-32 [1998] 13-35 13 35 33 *4

Potassium mg/kg 15 / 15 [1991] 1370-2820 [1998] 873-2150 873 2820 13000 *4

Sodium mg/kg 15 / 15 [1991] 303-311 [1998] 80-316 80 316 15000 *4

Thallium mg/kg 1 / 15 [1991] ND(2) [1998] 0.1 0.1 0.1 0.25 *6






Concentration



Vanadium mg/kg 15 / 15 [1991] 20.2-35.6 [1998] 12-49 12 49 129 *4

Zinc mg/kg 15 / 15 [1991] 29.4-51.2 [1998] 29-57 29 57 79 *4

NOTES:Footnote *1 = Not all nondect (ND) parameters are shown in table.Footnote *2 = See Data sets in Appendices.

B = analyte found in associated blank as well as in sample.

J = value is estimated and below quantitation limit.

Footnote *3 = Jacobs Engineering Group (August 2000) Summary Report 1999 Remedial Investigation / Removal Acton, Fort Greely, Alaska.Footnote *4 = United States Geological Survey (USGS) Professional Paper 1458, “Element Concentrations in Soils and Other Surficial materials of Alaska,” 1988.

Footnote *5 Surficial Materials of the Conterminous United States,” 1984.

Footnote *6 = United States Department of Agriculture, Forest Service, “A Summary of Background Concentrations for 17 Elements in North American Soils,” February 1990.


TABLE 6-2INITIAL SCREENING USING ADEC METHOD TWO LEVELS

SITE 85 SOUTH, FORT GREELY, ALASKA

Parameter Units Maximum Reported

Concentration

Frequency Detected > ADEC Method 2 Levels

ADEC Method 2 Ingestion Level

ADEC Method 2 Inhalation Level

ADEC Method 2 Migration to

Groundwater Level Exposure Route Exceeded

Parameter used in Cumulative Risk

CalculationsPETROLEUM HYDROCARBONS (FUELS)

Gasoline Range Organics (GRO) mg/kg 700 2 / 38 1,400 1,400 300 Migration to Groundwater

Diesel Range Organics (DRO) mg/kg 4800 32 / 42 10,250 12,500 250 Migration to Groundwater

Residual Range Organics (RRO) mg/kg 3500 0 / 17 10,000 22,000 11,000

VOLATILES

Benzene mg/kg 0.0942 J 7 / 45 290 9 0.02 Migration to Groundwater

Toluene mg/kg 0.627 0 / 38 20,300 180 5.4

Ethylbenzene mg/kg 0.25 0 / 38 10,000 89 5.5

Xylenes (total) mg/kg 13 0 / 38 203,000 81 78 Exceeded 1/10 of inhalation limit

Sec-Butylbenzene mg/kg 0.3 n / a - No ADEC limit

Tert-Butylbenzene mg/kg 0.1 n / a - No ADEC limit

cis-1,2-Dichloroethene mg/kg 0.06 0 / 17 1000 0.2

Isopropylbenzene (cumene) mg/kg 0.21 0/17 10100 585 227

4-Isopropyltoluene (cymene) mg/kg 0.89 n / a - No ADEC limit

n-Propylbenzene mg/kg 0.4 n / a - No ADEC limit

Tetrachloroethylene (PCE) mg/kg 0.09 J 1 / 17 160 80 0.03 Migration to Groundwater

1,2,4-Trimethylbenzene mg/kg 6.3 0/17 5070 92.2 95.2

1,3,5-Trimethylbenzene mg/kg 25 1 / 17 5070 38.3 25 Migration to Groundwater





Concentration







CalculationsSEMIVOLATILES

Acenaphthene mg/kg 0.5 J 0 / 29 6,100 210

Anthracene mg/kg 0.3 J 0 / 29 30,000 4300

Benzo(a)anthracene mg/kg 2.4 0 / 29 11 6 Exceeded 1/10 of ingestion limit

Benzo(b)fluoranthene mg/kg 4.4 0 / 29 11 20 Exceeded 1/10 of ingestion limit

Benzo(a)pyrene mg/kg 5.1 10 / 29 1 3 Ingestion, Migration to Groundwater

Benzo(g,h,i)perylene mg/kg 2.4 0/29 3000 1500

Bis(2-ethylhexyl)phthalate (DEHP) mg/kg 0.7 0 / 17 590 1200

Chrysene mg/kg 3.2 0 / 29 1,100 620

Dibenzofuran mg/kg 0.2 0 / 17 400 15.6

Dibenz(a,h)anthracene mg/kg 0.77 0 / 29 1 6 Exceeded 1/10 of ingestion limit

Fluoranthene mg/kg 3.4 0 / 29 4,100 2100

Fluorene mg/kg 0.9 0 / 29 4,100 270

Indeno(1,2,3,-cd)pyrene mg/kg 2.8 0 / 29 11 54 Exceeded 1/10 of ingestion limit

2-Methylnaphthalene mg/kg 2.5 0 / 29 4100 43

Naphthalene mg/kg 2.7 0 / 32 4,100 43

4-Nitrophenol mg/kg 0.5 n / a - No ADEC limit

Pentachlorophenol mg/kg 35 0.01

Phenanthrene mg/kg 1.3 0 / 29 30000 4300

Di-n-butyl phthalate mg/kg 0.2 0 / 17 10,000 1700

Pyrene mg/kg 4 0 / 28 3,000 1500





Concentration







CalculationsPESTICIDES/INSECTICIDES

Aldrin mg/kg 0.0072 0 / 122 0.5 24 1.6

BHC (a) (6) (HCH alpha) mg/kg 0.007 J 1 / 122 1.3 5.5 0.0026 Migration to Groundwater

4,4-DDD mg/kg 0.59 74 / 122 35 47

4,4-DDE mg/kg 0.033 60 / 122 24 150

4,4-DDT mg/kg 0.39 87 / 122 24 5,300 88

Endosulfan mg/kg 0.0041 0 / 122 610 7

Endrin mg/kg 0.007 0 / 122 30 0.3

Heptachlor Epoxide mg/kg 0.002 0 / 122 0.9 33 0.2

Methoxychlor mg/kg 0.010 0 / 122 510 52

Dieldrin mg/kg 0.0032 0 / 122 0.5 8 0.015

POLYCHLORINATED BIPHENYLS

Total PCBs mg/kg ND 0 / 15 10 10 10

DIOXINS/FURANS

2,3,7,8 TCDD Equivalent (TEQ) mg/kg 1.17E-06 n / a - No ADEC limit

METALS

RCRA metals

Lead mg/kg 130 n / a - No ADEC limit

J = estimated value


TABLE 6-3ALTERNATIVE CLEANUP LEVELS (INDUSTRIAL/COMMERCIAL) BY ADEC METHOD THREE



Concentration

Frequency Detected Above ADEC Method 3

Alternative Cleanup Level (ACL)

ADEC Method 3 Ingestion ACL

(industrial)

ADEC Method 3 Inhalation ACL

(industrial)


Groundwater ACLExposure Route

ExceededPETROLEUM HYDROCARBONS (FUELS)Gasoline Range Organics (GRO) mg/kg 700 0 / 38 1,400 1,400 1,400Diesel Range Organics (DRO) mg/kg 4800 3 / 42 12,500 12,500 3,300 Migration to

Groundwater

VOLATILESBenzene mg/kg 0.0942 J 0 / 45 1970 7.4 0.114Sec-Butylbenzene mg/kg 0.3 0 / 17 20400 60.1 152Tert-Butylbenzene mg/kg 0.1 0 / 17 20400 104 149n-Propylbenzene mg/kg 0.4 0 / 17 20400 61.3 188Tetrachloroethylene (PCE) mg/kg 0.09 J 0 / 17 1100 92.6 0.2731,3,5-Trimethylbenzene mg/kg 25 0 / 17 102000 32.9 295

SEMIVOLATILESBenzo(a)pyrene mg/kg 5.1 0 / 29 7.82 70.34-Nitrophenol mg/kg 0.5 0 / 17 16400 956 5.91

PESTICIDES/INSECTICIDESBHC (a) (6) (HCH alpha) mg/kg 0.007 0 / 122 9.06 6.08 0.0223

DIOXINS/FURANS2,3,7,8 TCDD Equivalent (TEQ) mg/kg 1.17E-06 n/a

METALSRCRA metalsLead mg/kg 130 0 / 13

J = estimated value

To be determined

Cleanup Level for lead in an indrustrial scenario is 1000 mg/kg


STEP 4:

The following are the calculated cleanup levels for each chemical and pathway. Where values are provided for more than one pathway, the lowest of the values should be used as the soil cleanup level. All cleanup levels are in units of mg/kg. Any other chemical-specific requirements that must be considered follow the table of cleanup levels.

Chemical Name Chemical Type Ingestion Inhalation Migration to GW

Lead Inorganic

Benzo(a)anthracene

Organic 78.2 70.3

Benzo(a)pyrene Organic 7.82 36.1

Benzo(b)fluoranthene

Organic 78.2 217

Dibenzo(a,h)anthracene

Organic 7.82 67.2

Dioxin Organic

DRO (Total) Petroleum 12500 12500 3330

GRO (Total) Petroleum 1400 1400 1400

Benzene Organic 1970 7.4 0.114

Indeno(1,2,3-c,d)pyrene

Organic 78.2 613

4-nitrophenol Organic 16400 956 5.91

RRO (Total) Petroleum 22000 22000 22000

Tetrachloroethylene Organic 1100 92.6 0.273

Xylenes Organic 1000000 761

sec butylbenzene Organic 20400 60.1 152

tert butylbenzene Organic 20400 104 149

n-proplybenzene Organic 20400 61.3 188

1,3,5 trimethylbenze

Organic 102000 32.9 295

HCH, a- Organic 9.06 6.08 0.0223

Chemical Notes

DioxinDioxin cleanup levels must be determined on a site-specific basis.

DRO (Total)The Maximum Allowable DRO concentration is 12500 mg/kg.

GRO (Total)The Maximum Allowable GRO concentration is 1400 mg/kg.

These cleanup levels should be printed. To print, please select the print function on your web browser. This page may also be saved and emailed for documentation of the calculated cleanup levels. For best results, save the page as a "Web Archive for email" file (.mht) if your browser supports this; in Internet Explorer 5 choose "Save as..." from the file menu and change the "Saveas type" to "Web Archive for email". Other browsers should have a similar choice.

For reference, the parameters used to calculate these levels are as follows (with defaults that have been changed listed in parentheses):

Volatilization Pathway:

Groundwater Pathway:

The exposure scenario and zone for this project: Under 40-inch Zone - Commercial/Industrial Exposures Today's date: 3/1/02

Enter site name to view on printout:

If you wish to calculate cumulative risks based on concentrations that have been entered for the site, select the "continue" button below. If you do not wish to complete this step, please note that you must demonstrate that the calculated cleanup levels will not produce unacceptable cumulative risks before they will be accepted. If cumulative risks are above the benchmarks, the cleanup levels should be modified downwards. See the Guidance on Cleanup Standards Equations and Input Parameters for details.

LeadLead cleanup levels are 400 mg/kg for residential sites and 1000 mg/kg for commercial sites.

RRO (Total)The Maximum Allowable RRO concentration is 22000 mg/kg.

ρb: Dry soil bulk density (g/cm3): 1.5 (Default: 1.5 )

n: Total soil porosity (Lpore/Lsoil): 0.434 (Default: 0.434 )

Θw: Water-filled soil porosity (Lwater/Lsoil): 0.075 (Default: 0.15 )

Θa: Air-filled soil porosity (Lair/Lsoil): 0.359 (Default: 0.284 )

w: average soil moisture content (gwater/gsoil): 0.05 (Default: 0.1 )

foc: organic carbon content of soil (g/g): 0.0015 (Default: 0.001 )




K: aquifer hydraulic conductivity (m/yr): 30000 (Default: 876 )

i: hydraulic gradient (m/m): 0.002 (Default: 0.002 )

L: source length parallel to groundwater flow (m): 32 (Default: 32 )

I: infiltration rate (m/yr): 0.06 (Default: 0.13 )

da: aquifer thickness (m): 10 (Default: 10 )

Alternatively, to return to the first step to rerun the calculator or change parameters, click here.

Continue

STEP 5:

The following are cumulative cancer risks and hazard quotients by chemical. Note that petroleum ranges (GRO, DRO, and RRO) are not included in cumulative risks. Also, if PCBs or dioxins are present at the site, the cumulative risks associated with these chemicals may also need to be considered; please contact the ADEC project manager for your site for information on how to address these chemicals.

Overall totals are as follows:

Hazard Index: 0.76 Cancer Risk: 0.0000089

These cumulative risk levels should be printed. To print, please select the print function on your web browser. This page may also be saved and emailed for documentation of the calculated cumulative risks. For best results, save the page as a "Web Archive for email" file (.mht) if your browser supports this; in Internet Explorer 5 choose "Save as..." from the file menu and change the "Save as type" to "Web Archive for email". Other browsers should have a similar choice.

To revise concentrations and recalculate cumulative risks, click here. Alternatively, to return to the first step to rerun the calculator or change parameters, click here.

Chemical Name Concentration (mg/kg) Cancer Risk Hazard Quotient

1,3,5 trimethylbenze 25 0 0.76

4-nitrophenol 0.5 0 0.00055

Benzene 0.0942 1.3e-7 0

Benzo(a)anthracene 2.4 3.1e-7 0

Benzo(a)pyrene 5.1 0.0000065 0

Benzo(b)fluoranthene 4.4 5.6e-7 0

Dibenzo(a,h)anthracene 0.77 9.9e-7 0

Dioxin 0.00000117 0 0

HCH, a- 0.007 1.9e-8 0

Indeno(1,2,3-c,d)pyrene 2.8 3.6e-7 0

Lead 130 0 0

n-proplybenzene 0.4 0 0.0016

sec butylbenzene 0.3 0 0.0018

tert butylbenzene 0.1 0 0.00043

Tetrachloroethylene 0.09 9.8e-9 0.0000044

Xylenes 13 0 0.0000032


7.0 SITE 85 NORTH

This risk assessment is part of the “Soils Evaluation and Risk Assessment, Fort Greely BRAC, Site 85 South, Site 85 North, Site 133, Site 112,” (hereafter referred to as the REPORT). Site 85N is a former fire training area. The site is located north of the east end of the west taxiway of the Allen Army Airfield (See Figure 1-1 of the REPORT.). The site is located about 500 feet south of the centerline of the East-West Runway.

The site is industrial in nature located between the runway and a taxiway. The site is on retained property and is expected to remain an Army airfield into the indefinite future. The risk scenarios are industrial with actual exposure frequencies from the airfield operations and maintenance.

This report is considered a “streamlined” risk assessment. Due to the uncomplicated nature of Site 85N and the small area involved, a simplified version of the risk assessment as outlined in ADEC’s “Risk Assessment Procedures Manual” (ADEC 2000a) is warranted.

7.1 Introduction

Format of this risk assessment generally follows that identified in ADEC 2000a with some simplifications. This streamlined assessment uses many of the standard default input parameters that are found in ADEC 1999, EPA 2000, and EPA 1996. The site risks are calculated using the equations derived from EPA 2000 and ADEC 1999. The fate and transport equations and risk calculations incorporate conservative assumptions, which are documented in the above references. References to other sections of the REPORT will be identified as such.

7.1.1 Site Description Site 85 North is a former fire training pit, and was previously referred to as “GFTP-4B” in documentation prior to Base Realignment and Closure (BRAC) work. Site 85 North is located north of the east end of the west taxiway of Allen Army Airfield (Figure 1-1 of the REPORT). The site is located approximately 500 feet south of the centerline of the East-West Runway. Photo 7-1 and Photo 7-2 show Site 85 North on 16 August 2000. Figure 7-1 shows the approximate locations of investigation activities that have been conducted at the site.

Based on USACE (1994), Site 85 North was a depression with a rectangular pit located near the center. Drums were stored on the southwestern side of the fire training pit according to 1969 aerial photographs.

The following site history summary is based on AGRA 1998. The U.S. Army Environmental Hygiene Agency first documented the presence contamination at the site in 1986. Ecology & Environment, Inc. (E&E) conducted a soil boring and sampling program at the site in 1991 and 1992. Fuel products, pesticides, and dioxin were found at the site to a depth of 11.5 feet. AGRA collected analytical samples during the installation of biovent wells in 1994. AGRA’s 1994 analytical results documented petroleum and pesticide contamination to 17 feet below ground surface (bgs) inside the former fire training pit area.


Between 1994 and 1997, AGRA developed, installed, and operated an insitu bioventing treatment system at Site 85 North and performed insitu landfarming to a depth of five feet bgs. The bioventing treatment system consisted of four air injection wells, constructed of 4-inch diameter PVC pipe with 0.050-inch slot screen installed from five to 25 feet bgs. The wells were fitted with in- line duct fans powered by photovoltaic solar collectors.

Landfarming at Site 85 North consisted of berming the site, tilling soil inside the bermed area, and installing and operating an irrigation system. Tilling was accomplished by digging and backfilling a series of trenches across the site. The trenches, advanced to a depth of approximately five feet bgs, were backfilled with the excavated soil. The irrigation system consisted of piping and a pump that transferred water from Jarvis Creek to the sites. Soil samples were collected from the land farmed soil intermittently during the treatment process.

After two years of operating and monitoring the treatment system, AGRA concluded that, based on the results of respiration tests (oxygen and carbon dioxide), the biovent wells were successful at aerating the subsurface soil and biologic activity was occurring. AGRA also concluded the data did not support further operation of the remediation system, and recommended collecting confirmation samples.

Sampling was conducted at Site 85 North during 1998 under the BRAC LRI program. This work included conducting an initial site evaluation, drilling soil borings, collecting soil samples, and conducting field screening. The biovent system remains in place at Site 85 North, but is not active.

A soil cap was placed atop the area of contamination at Site 85 North during summer 2002, subsequent to conducting the risk assessment described herein. Therefore, the risk assessment does not account for the soil cap. That is, the soil cap provides additional protection against exposure to contaminants, and added assurance that the input used in the risk assessment is conservative with regard to site conditions.

7.1.2 Characterization of the Physical Setting Characterization of the physical setting is found in Section 3 (Generalized Fort Greely Physical Characteristics) and Section 4 (Conditions Specific to the Fort Greely Cantonment Area) of the REPORT.

7.1.3 General Site Map The general site map is found as Figure 1 (Location Map, Sites 85 South, 133, 112, and 85 North) and Figure 4-1 (Well Locations, Fort Greely, Alaska) of the REPORT.

7.1.4 Specific Site Map The specific site map is found below as Figure 7-1 (Sample Location Map)

7.1.5 Additional Site Maps Additional site maps can be found in Appendix 85N of the REPORT.


7.1.6 Photographs Two ‘on the ground’ photographs are found as Photo 7-1 and Photo 7-2 below. These two were taken 16 August 2000. Aerial photographs can be found in Section 2 of the REPORT. These aerial photographs were taken 1 July 1999.


Photo 7-1, Site 85 N

16 August 2000, Looking northwest at Site 85 North from south of the runway tarmac.

Photo 7-2, Site 85 North

16 August 2000, Looking northwest at Site 85 North from south of the runway tarmac.


7.2 Refined Human Health Conceptual Site Models

The human health conceptual site model has been modified from that found in earlier draft versions of the REPORT. It was modified based on the risk assessment scoping meeting held on 24 October 2001 between USARAK, USAED and ADEC and subsequent comments from ADEC. The CSM is shown in Appendix D of this risk assessment.

The contamination source is limited to the surface and subsurface contaminated soil on site (results of past fire training exercises). The release mechanism is limited to migration to subsurface soils. Exposure routes are limited to on-site receptors and include incidental ingestion, dermal contract, and inhalation of volatiles and particulates. The current and future on-site receptors are maintenance workers at the airfield. There are no current off-site receptors. (See Groundwater Considerations)

7.3 Selection of Compounds of Potential Concern

7.3.1 Identified Documentation and Past Site Activity – Site 85 North The following documents provide information about Site 85 North. Selected items of supporting documentation are included in Appendix 85N of the REPORT.


2. Ecology and Environment, Inc. (August 1992) Fire Training Pits Work Plan, Part 1, Fort Richardson and Fort Greely, Alaska. The document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 85 North is referred to as “GFTP4B”.

3. Ecology and Environment, Inc. (August 1992) Fire Training Pits Work Plan, Part 2, Subsurface Exploration Plan, Fort Richardson and Fort Greely, Alaska. The document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 85 North is referred to as “GFTP4B”.

4. USAED (March 7, 1994) Site Assessment/Corrective Action Plan, Three Former Fire Training Pits, Fort Greely, Alaska. The report documents investigation activities at the site. The document presents the results of the investigation work conducted by E&E associated with the 1992 work plans referenced above. The document presents a hazard assessment and a corrective action plan. Section 5 of the document, titled “Soil Cleanup Levels” describes the process and results calculating risk-based screening levels under an industrial/commercial scenario for BNA, pesticides, and dioxin.

5. USAED (April 1994) Environmental Assessment and Finding of No Significant Impact, Remedial Treatment of Petroleum Contaminated Soils, Fire Training Pits, Fort Greely, Alaska.

6. AGRA Earth & Environmental, Inc. (May 1995) Final Remedial Design Report, Contract No. DACA85-94-D-0011, Fire Burn Pits Treatment System, Fort Greely, Alaska. The


report presents a design for performing in-situ bioremediation at the site. The design includes landfarming of near-surface soils, followed by installation of biovent wells, each with a solar powered low-power blower system.

7. AGRA Earth & Environmental, Inc. (July 1998) Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska. The report summarizes the activities and findings of the design, installation, and operation of the in-situ bioremediation treatment system at the site.

8. Jacobs Engineering Group Inc. (April 1999) 1998 Remedial Investigation Report, Fort Greely, Alaska, Final. Section 18.0 of the report presents the methodology and results of additional investigation activities conducted at the site under the BRAC LRI program.

9. Radian International / Jacobs Engineering Group Inc. (August 2000) Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska, Final. Section 3.5.4 of the report summarizes the affect of additional background investigation on Chemicals of Potential Concern (COPC) for the site.

Pre-BRAC Investigation Activities

E&E conducted sampling in 1991. The work included the following.

• Four borings were drilled (AP-532, AP-533, AP-534, and AP-535) to depths ranging from 12 to 16.5 feet bgs. Total drilling footage was 61 feet.

• Soil samples were collected, generally at 4.5, 9.5, and 14.5 feet bgs.

• Soil samples were analyzed for VOC, BNA, Fuel Identification (8015 Modified), pesticides, PCBs, dioxin/furan, and metals.


• Eleven borings were drilled (AP-585, AP-586, AP-587, AP-588, AP-589, AP-590, AP-591, AP-592, AP-593, AP-594, AP-595). Depths of drilling ranged from 21.5 to 46.5 feet bgs. Total drilling footage was 375.5 feet.

• Fifteen surface soil samples were collected from the fire training pit area.

• Selected soil samples were analyzed for BTEX, Fuel Identification, DRO, lead, TCLP lead, pesticides, PCBs, BNA, and dioxin/furan.

• Three sieve analyses were conducted.

AGRA designed, installed, operated, and monitored an insitu treatment system at the site from 1994 through 1997. The work included the following.

• Seven soil borings were drilled for installation of the system components (B-B1, BMP- 1, B-MP-2, B-MP-3, B-B2, B-B3, andB-B4). Total drilling footage was 159.5 feet.

• The upper five feet of impacted soil in the former fire training pit area was landfarmed by trenching, irrigating, turning, and backfilling. Four biovent wells with integral blowers


were installed and operated. Respirometry was conducted intermittently during system operation.

• Soil samples were collected from the site a) during system installation, and b) intermittently during operation and monitoring of the soil treatment system.

• Selected soil samples were analyzed for DRO, GRO, BTEX, PAH, pesticides, and bio-treatability parameters.

1997 Investigation Activities Activities were not conducted at the site during 1997 BRAC efforts.

1998 Investigation Activities JEG drilled and sampled the site in 1998. The work included the following.

• Two soil borings were drilled (AP-915, AP-916). Both borings were located inside the former fire training area. Depths of drilling were 32 and 47 feet bgs, for a total drilling footage of 79 feet.

• Selected soil samples were analyzed for DRO, RRO, GRO, VOC, SVOC, pesticides, PCBs, metals, dioxins, furans, TEQ, TOC, HPC, and ODB.

1999 Investigation Activities Activities were not conducted at the site during 1999 BRAC efforts. However, additional background sampling results did affect the COPCs for the site.

7.3.2 Target Analyte List / Target Compound List (modified) Site sampling occurred at 85N in 1991, 1992, 1994, 1995, 1995-1997 (landfarm samples) and 1998. Since this was a fire training area, suspected compounds included petroleum fuels, volatile organic compounds (VOCS), semi-volatile compounds (SVOCS), polychlorinated Biphenyls (PCBs), solvents, pesticides, metals, and dioxins.

A list of chemicals of potential concern (COPC) was developed starting with the ADEC analytes listed for unknown spills (ADEC 2000b). This list included GRO, DRO, RRO, BTEX, PAHs, arsenic, cadmium, chromium, lead, PCBs, and volatile chlorinated compounds. To this list was added any compound that was detected at either Site 85N, 85S or 133. (Sites 85S and 133 are nearby sites also used for fire training activities.)

The full list of COPC is included in Table 7-1.


Table 7-1 - Sites 85S, 85N, & 133 COPC (See following text for explanation of symbols.)

PETROLEUM HYDROCARBONS (FUELS) PESTICIDES/INSECTICIDES Gasoline Range Organics (GRO) Aldrin (nd) Diesel Range Organics (DRO) BHC (a) (6) (HCH alpha) (nd) Residual Range Organics (RRO) Chlordane (nd)

4,4-DDD

VOLATILES 4,4-DDE Benzene 4,4-DDT Toluene (S) Endosulfan (nd) Ethylbenzene (ND) Endrin (nd) Xylenes (total) (S) Heptachlor Epoxide (nd) Sec-Butylbenzene (ND) Methoxychlor (nd) Tert-Butylbenzene (ND) Dieldrin cis-1,2-Dichloroethene (ND) 1,2-Dibromoethane (ND) POLYCHLORINATED BIPHENYLS Methylene chloride (nd) Isopropylbenzene (cumene) (ND) Total PCBs (nd) 4-Isopropyltoluene (cymene) (ND) n-Propylbenzene (ND) DIOXINS/FURANS Tetrachloroethylene (PCE) 2,3,7,8 TCDD Equivalent (TEQ) 1,1,1-Trichloroethane 1,2,3 trichlorobenzene (ND) METALS 1,2,4-Trimethylbenzene (ND) RCRA metals 1,3,5-Trimethylbenzene (ND) Arsenic (BK)

Barium (BK)

SEMIVOLATILES Cadmium (nd) Acenaphthylene (ND) Chromium (7) (BK) Acenaphthene (ND) Lead Anthracene (ND) Mercury (nd) Benzo(a)anthracene (ND) Selenium (BK) Benzo(k)fluoranthene (ND) Silver (ND)

Benzo(b)fluoranthene (ND) Other metals Benzo(a)pyrene Aluminum (BK) Benzo(g,h,i)perylene (ND) Antimony (BK) Bis(2-ethylhexyl)phthalate (DEHP) (ND) Beryllium (BK) Chrysene (S) Calcium (BK) Dibenz(a,h)anthracene (nd) Cobalt (BK) Fluoranthene (S) Copper (BK) Fluorene (ND) Iron (BK) Indeno(1,2,3,-cd)pyrene (ND) Magnesium (BK) 2-Methylnaphthalene (ND) Manganese (BK) Naphthalene (ND) Nickel (BK) 4-Nitrophenol (ND) Potassium (BK) Phenanthrene (ND) Sodium (BK) Di-n-butyl phthalate (ND) Thallium (BK) Pyrene (S) Vanadium (BK) Zinc (BK)


7.3.3 Nondetected Parameters Sampling at Site 85N has produced many nondetect (ND) results. NDs were addressed in one of the following ways.

If all results for a particular analyte returned all ND and the detection levels were all below 1/10-th of the lowest ADEC Method 2 cleanup level, the compound was not considered to be present on site and dropped as a COPC. Compounds dropped as COPC in this manner are identified with a (ND) in Table 7-1. Twenty-six compounds and one metal (silver) were in this ND category.

If all results for a particular analyte returned all ND and some of the detection levels were below 1/10-th of the lowest ADEC Method 2 cleanup level, the compound was further evaluated. If there were an adequate number of low detection level NDs, the compound was not considered to be present on site and dropped as a COPC. Compounds dropped as COPC in this manner are identified with a (nd) in Table 7-1.

• Dibenzo(a,h)anthracene: The lowest ADEC cleanup level is 1 mg/kg. Detection limits for 1998 were 0.3 mg/kg and for 1996 were 0.01 mg/kg. Therefore, the ND samples are valid and this is not considered a Chemical of Concern (COC).

• Aldrin, Endrin, and Heptachlor Epoxide: The lowest ADEC cleanup levels for these three are 0.5 mg/kg, 0.3 mg/kg, and 0.2 mg/kg respectively. These compounds were not detected anywhere at 85N. Two of the samples from 1991 have a DL that exceeds the ADEC level. Several samples in 1996-97 also have DL greater than the ADEC level. However in 1995, in the area where other pesticides were detected there is also a triplicate sample for Aldrin and Heptachlor Epoxide with ND and the North Pacific Division (NPD) Laboratory QA sample has a low DL of 0.032 mg/kg. Other samples from 1991 and 1996-97 have low DL. Sample results from 1994 have DL of 0.003 mg/kg or less and 1998 all have DL of 0.01 mg/kg. Therefore, because there are ample samples with low DL that cover the site, and the analytes were not detected, it is reasonable to conclude that all the ND are valid.

• Alpha-BHC: The lowest ADEC cleanup level for this is 0.0026 mg/kg. This compound was not detected at 85N. Analysis for this compound was only performed in 1991 and 1998. DL in 1998 was 0.01 mg/kg. For 1991, DL ranged from about 0.008-0.016 mg/kg for eight samples, and 0.8 mg/kg for one and 10.2 mg/kg for one. This compound was detected at site 133 and 85S. DL for these was also 0.01 mg/kg. However, the analysis was able to detect at levels of 0.002 mg/kg. A check with the laboratory shows a method detection limit of 0.002 mg/kg. So it would appear that if α-BHC were present at site 85N at levels above 0.0026 it should have also been detected and flagged. Therefore, it is not considered a Chemical of Concern (COC) for 85N.

• Pesticides/Insecticides: No others were detected at site 85N. The other COPC in this group are chlordane, endosulfan, and methoxychlor. In 1991, the 2 samples at AP-533 were diluted resulting in high DL that exceeds the ADEC levels. However, sampling in 1998 had DL less than the ADEC levels and all were nd. Also, in 1994, sampling for Methoxychlor was performed with all ND and a high DL of 0.0099. So these analytes are not COC for site 85N.


• Total PCBs: No PCBs were detected at Site 85N. Sampling in 1991 included 16 nd. 14 of these had DL of 0.16-0.36 mg/kg. Two of the samples (at AP-533) were diluted and DL was 8.2 mg/kg and 102.2 mg/kg. Sampling in 1992 included 20 samples. Three of these had DL ranging from 2.4 – 8.8 mg/kg. The rest had high DL above 10 mg/kg, up to 2175 mg/kg. Sampling results in 1998 were all ND with DL of 0.10 mg/kg. Given that PCBs have not been detected at the site and that most of the samples including the latest sampling have a DL limit below 0.10 mg/kg we conclude that PCBs are not a COC for this site. Also, no PCBs were detected at site 133 or 85S.

• Metals: Cadmium was ND at a detection limit of 1.0. While this is above the screening level of 1/10-th of the cleanup level (0.1 x 5 = 0.5), it is below the lowest ADEC cleanup level of 5 mg/kg. It is not considered a COC. Mercury is also not a COC with detection limits that ranged from 0.1 mg/kg to 0.2 mg/kg. The lowest ADEC cleanup level is 1.4 mg/kg.

If results for a particular analyte returned low positive results and nondetects with a high detection limit, the compound was considered to be present at the positive result level if sufficient nondetects were at low levels. It was not considered to be present at a higher level (and masked by the high detection level NDs).

• Benzene: Data Table includes all data from 1991 – 1998. The lowest ADEC Cleanup Level is 0.02 mg/kg. All 1998 data is ND (7 samples), but DL for 1998 is at 0.05 mg/kg. 1996-97 data includes 21 ND with DL below 0.02 mg/kg. This post-remediation data may be enough info to show no benzene is present. However, the pre-remediation data is also evaluated. 1992, 1994, & 1995 includes 65 ND with DL below 0.02 mg/kg and 13 hits below 0.02 mg/kg. The 1992 data also includes four detections above 0.02 mg/kg. Two of these at levels of 0.029 mg/kg and 0.045 mg/kg were taken at depth (25’ and 20’), but within the SVE depth. The other two (0.091 mg/kg & 0.550 mg/kg) are from the top five feet, which was extensively turned for land farming and therefore should have been remediated by now.

• Tetrachloroethylene: The lowest ADEC Cleanup Level is 0.03 mg/kg. 1998 data includes 6 ND samples but DL was at 0.05 mg/kg. No chlorinated compounds were detected as a source for PCE during this sampling and so no PCE is expected to be at this site. This was also sampled for in 1991 with 6 ND and 3 detections below 0.03 mg/kg (DL at 0.006). Two samples in 1991 were detected above 0.03 mg/kg – at 0.076 mg/kg and 0.177 mg/kg. However, because this site was extensively land farmed, it is likely that these would have been remediated by now.

• Benzo(a)pyrene: The lowest ADEC cleanup level is 1 mg/kg. Detection limits for 1998 sampling was 0.3 mg/kg. Sampling from 1996 and 1994 had DL of 0.01 mg/kg and 0.05 mg/kg respectively. One detection was found in 1996 at 0.054 mg/kg. The DLs are low enough to conclude that the NDs are valid.

• DDE. The lowest ADEC Method 3 cleanup level for DDE is 24 mg/kg. Some of the detection levels were above 2.4 mg/kg (one-tenth of the cleanup level). However 16 of


175 samples were under the 2.4 mg/kg and 173 of 175 were under 24 mg/kg. In the DDE case, the high positive hit of 6.2 mg/kg is considered to represent the high concentration.

• Dieldrin: The lowest ADEC Cleanup Level is 0.015 mg/kg. Dieldrin was detected in 2 samples in 1996-97 at 0.089 mg/kg and 0.045 mg/kg. These samples were from the landfarming operations and therefore cannot be associated with a definite location other than the general area (B1 and B3). In 1991, 10 samples were ND but DLs were above 0.015 mg/kg for all but 1 sample. Sampling in 1992 included 46 ND subsurface samples with a DL of 0.015 mg/kg or less. There were also 12 ND subsurface samples with higher DL (0.031 mg/kg – 3.2 mg/kg). Also, 18 ND surface samples were collected with DL of 0.08 mg/kg – 82.5 mg/kg. Because this site was subject to land farming this surface soil has been moved extensively. In 1994, there were 18 ND with DL from 0.00094 mg/kg to 0.0031 mg/kg. In 1995 a triplicate sample was taken that had high detections of DDD, DDE and DDT. The DL for the primary labs primary sample and QC was at 0.32 mg/kg. But the DL for the QA lab (NPD) was 0.0064 mg/kg. In 1998, there were 6 ND with DL of 0.01 mg/kg. Due to the high number of samples that are ND with low DL, it is reasonable to conclude that all of the ND values are valid. Therefore, we can conclude that the only detections for dieldrin at 85N are the 2 samples from 1996-1997.

Blank contamination: Methylene Chloride. The lowest ADEC cleanup level is 0.015 mg/kg (migration to groundwater). Methylene Chloride is a common lab contaminant. Results from 1991 sampling included several detections below the ADEC level, with two of the detections B flagged for possible cross contamination. Sampling in 1998 gave 7 ND with DL of 0.1-0.2 mg/kg. Therefore, the ND samples are valid and so this compound is not a COC for Site 85N.

7.3.4 Human Health Risk-based Screening Using Maximum Concentrations This screening was accomplished according to the ADEC guidance except that instead of using 1/10-th of the lowest cleanup value as a screening level, 1/100-th of the lowest cleanup level was used. The 1/100th of the cleanup levels were used due to the number of COPCs on site. Compounds dropped as COPC in this manner are identified with an (S) in Table 7-1. The five compounds that fell into this category are toluene, xylenes, chrysene, fluoranthene, and pyrene.

7.3.5 Background Comparison Using Maximum Concentrations Background metals comparisons have been made under Fort Greely BRAC. In addition to the site-specific background concentrations, regional background concentrations were also examined. Background concentrations are shown in Table C.1 of Appendix C to this Risk Assessment. Other than lead and selenium, all metals are within background ranges. Selenium detected at 1 mg/kg is above the local background of 0.3J mg/kg. National background average is 0.39 mg/kg with a range of <0.1 mg/kg to 4.3 mg/kg. Although selenium is above the background average, it is within a range that could be considered naturally occurring. CERCLA (40 CFR 300 App. A) considers a release to have occurred if the detected concentration is within three times background. Selenium is not considered a COC. Compounds dropped as COPC in this manner are identified with a (BK) in Table 7-1.


7.3.6 Data Gaps The only data gaps for this assessment are thorough post treatment sampling and analysis. To address this gap, pre-remedial sampling results are included for assessment.

7.3.7 Data Usability Each investigation on site has had its separate data quality review. An evaluation of the detection limits has been made as part of this assessment. All data is of sufficient quality to support the decisions made for the site.

7.3.8 ADEC Human Health Compounds of Potential Concern Data Presentation Table This table follows Table A.1 of ADEC 2000a with slight modifications. Not all non-detect compounds from Table 7-1 are carried into the Data Presentation Table (See Table C.1 of Appendix C of this risk assessment).

7.3.9 Human Health Compounds of Concern Considering the non-detects, screening, and background concentrations, the table of COPC is reduced to a listing of COC. These COC compounds are listed in Table 7-2.

7.4 Human Health

7.4.1 Exposure Assessment The objective of the exposure assessment is to estimate the type and magnitude of exposures to the compounds of concern that are present at the site, migrating from the site, or have the potential to migrate from the site.

Land Use Current land use at Site 85N is industrial/commercial. The site is vacant and is located between the runway and a taxiway at the Allen Army Airfield on Fort Greely. See Figure 1-1 of the REPORT, and Photos 7-1 and 7-2.

Future land use will not change from the current use. This site is on retained military land. Future land use for the remainder of Fort Greely will also remain in Department of Defense inventory. There is no future plan to excess any of this property. Institutional controls to maintain the land use classification will be addressed after and separately from this risk assessment.

• Current ownership of this site is the U.S. Army, Alaska (USARAK).

• There are no subleases existing or planned for this site.

• There is no zoning on the military base. This site is within the lateral clear zone of the East-West Runway.

• The site is in a restricted area on the airfield.


• Adjacent land includes the East-West Runway, West Taxiway, aircraft parking apron, and Butternut Road.

Scenarios / Potentially Exposed Populations The Fort Greely population is 461 (2000 US Census). Future population will vary depending on the implementation of the National Missile Defense (NMD) program (Fort Greely is a potential site in the NMD program). Probable scenarios run from population decline to a slight increase. The 85N site is in a restricted area adjacent to the airfield. The general population will not come in contact with this site. The only potentially exposed population is the maintenance crew that cuts the vegetation back once a year.

As agreed in the risk assessment scoping meeting, the actual worker exposures will be used for the assessment at Site 85N. The exposure frequency (EF) for on-site workers is 1/2 hours per year. This is based on the current and future maintenance schedule for the Site 85N. Currently, the only exposure is an annual brush and grass cutting conducted with a tractor and brush-hog attachment. A figure of one day per year will be used as a conservative estimate for cutting the Site 85N area. This EF is not anticipated to change in the future.

There are no current off-site potentially exposed populations. Modeling done previously on Fort Greely indicates that contaminants at the concentrations found at Site 85N will not leach to the ground water (about 170 to 180-feet below ground). See Groundwater Considerations (7.4.1.5) below.

Subsistence Subsistence is not an issue at Site 85N. It is a restricted area, no subsistence activities currently take place and none are expected in the future. The contamination does not effect subsistence areas elsewhere. The contamination will not migrate off site to other areas and contamination will not progress up the food chain (See ecological assessment 7.6).

Pathways Exposure pathways are identified in the Conceptual Site Model (CSM) (See Appendix D of this risk assessment.). The Contaminant source is contaminated surface and subsurface soil.

On-site exposure routes are incidental ingestion, dermal contact and inhalation of volatiles and particulates. Current and future receptors are the site maintenance workers.

Groundwater Considerations The aquifer at the site is Class (1)(a) under 18 AAC 70 (water supply for drinking, culinary, and food processing; agriculture, including irrigation and stock watering; aquaculture; and industrial).

The nearest water supply wells are wells #3 and #4, which are about 2,200 feet WSW of the site. Well #E2 is about 2,200 feet south. Well #1 is about 3,000 feet WSW. The gradient is 0.002 to 0.007 FT/FT in a northeast direction. Water depths at these wells have varied from about 170-FT to 180-FT below ground surface. Hydraulic conductivity is approximately 2,019 gpd/FT2 (270 ft/day). Water supply is through mains enclosed in utilidors.


The Wellhead Protection radii for the two of the three nearest wells are 1,365-feet for well #1 and 1,264-feet for well #4. Well #3 is inactive and does not have an established radius. Periodic groundwater monitoring at Fort Greely was started in 1990. Groundwater sampling has been conducted periodically during the 1990’s, once during 2000, and twice during 2001. Low-level detections of DRO and several other organic compounds have been reported. However, reported detections have not been consistent and have been below regulatory criteria. Reported detections are believed to be the result of laboratory and/or sampling interference, and are not believed to be the result of contaminant migration to groundwater. Groundwater monitoring is scheduled to continue. Pesticides have not been detected in the groundwater. TCE at low levels has been detected at Site 88 (old landfill 4,500-ft south of Site 85N). Fall 2001 sampling was non-detect for TCE.

Based on the leachability modeling done to date, it appears that the migration to groundwater pathway is not complete. SESOIL modeling for several sites across Fort Greely is documented in JEG 2001. The closest site to Site 85N was Site 73 which is about 3500 feet SW of Site 85N. Contaminants modeled included methylene chloride, GRO, DRO, BTEX, naphthalene, and dioxins/furans. Contaminant concentrations were higher than that found on Site 85N. Although PCE and trichloroethane were not modeled, benzene and methylene chloride were. Benzene and methylene chloride are fast movers in the soil. (benzene Koc = 58.9 mg/L; methylene chloride Koc = 11.7 mg/L; toluene Koc = 182 mg/L; naphthalene Koc = 2000 mg/L; PCE Koc = 270 mg/L; trichloroethane Koc = 110 mg/L.)

At Site 30, benzene reached the groundwater after 71 years but at a concentration of 0.0000178 mg/L (ADEC Table C cleanup value is 0.005 mg/L). This model run started with maximum benzene in soil concentration of 3.2 mg/L (maximum at Site 85N is 0.55 mg/kg).

At Site 73, benzene broke through to the groundwater after 60 years at a concentration of 0.00021 mg/L. Initial maximum soil concentration was 6.1 mg/kg.

At Site 116 benzene reached the groundwater after 40 years at a concentration of 0.000063 mg/kg. Initial maximum soil concentration was 0.21 mg/kg.

At Site 133 methylene chloride reached the groundwater after 27 years at 0.000394 mg/L (ADEC Table C cleanup value is 0.005 mg/L.). Initial maximum soil concentration was 0.013 mg/kg. This maximum soil contamination used for the model for methylene chloride is the same concentration as the maximum measured on Site 85N for 1,1,1-trichloroethane. The Koc for 1,1,1-trichloroehtane is an order of magnitude higher than that of methylene chloride.

At site 112, methylene chloride hit the groundwater after 31 years at 0.0061 mg/L. Using a degradation rate of 0.0052/day, breakthrough occurred at 2.4x10-9mg/L. The initial maximum soil concentration for the model run was 0.24 mg/kg.

Although the SESOIL modeling done to date varied some in the soil layering, results indicate that for contaminants detected at Site 85N and their maximum concentrations, migration to groundwater is not a viable pathway.


Exposure Point Concentrations and Intakes The exposure point concentrations for incidental ingestion and dermal contact are the compound concentrations measured on site. Measured concentrations can be expressed as the maximum detected, the central tendency (average), or the 95% Upper Confidence Limit (UCL). The reasonable maximum exposure is normally taken as the 95% UCL. The 95% UCL of a mean is defined as a value that, when calculated repeatedly for randomly drawn subsets of site data, equals or exceeds the true mean 95% of the time. The 95% UCL of the mean provides a conservative estimate of the average (or mean) concentration. The table below shows the maximum detected concentrations, the central tendency (average) concentrations, and the 95% UCLs. This risk assessment will use the maximum concentrations detected on site as the reasonable maximum exposures. (See Table 7-2.)


Table 7-2 – COC Concentrations

COMPOUND MAXIMUM CONC (mg/kg)

CENTRAL TENDENCY (AVERAGE) CONC (mg/kg)

95% UCL CONC (mg/kg)

PETROLEUM HYDROCARBONS (FUELS) Gasoline Range Organics (GRO) 260 17.2 not used Diesel Range Organics (DRO) 2400 504.8 not used Residual Range Organics (RRO) 570 247 not used

VOLATILES Benzene 0.55 0.045 not used Tetrachloroethylene (PCE) 0.177 0.053 not used 1,1,1-Trichloroethane 0.013 0.013 not used SEMIVOLATILES Benzo(a)pyrene 0.054 0.054 not used

PESTICIDES/INSECTICIDES 4,4-DDD 220 18.6 220 4,4-DDE 6.2 1.0 not used 4,4-DDT 150 15.1 150 Dieldrin 0.089 0.067 not used

DIOXINS/FURANS 2,3,7,8 TCDD Equivalent (TEQ) 3E-05 6.28E-06 not used

METALS Lead 746 range: 3.4 to 746 not used

Exposure point concentrations for volatiles and particulates in air were calculated as part of the standard EPA risk equations (EPA 2000, EPA 1996). The starting points for these concentrations were the maximum soil concentrations listed above.

Calculation of contaminant intake into the body relied on the standard EPA and ADEC equations and parameters (with a few site specific modifications). See Table C.2 of Appendix C of this risk assessment.

Soil Exposure Depths Inhalation of particulates is dependent on the soil concentrations within the surface soils. Inhalation of volatiles is dependent on the surface and subsurface soil contaminant concentrations. The 85N site has had extensive landfarming within the top five feet. Since the current distribution of contaminants in the soil is not known, the maximum concentrations detected for each contaminant, regardless of depth, are used in the risk calculations.

Deterministic Risk Assessment This is a deterministic risk assessment. A probabilistic assessment is not undertaken.


Types of Exposures This assessment considers only chronic exposures. The only relatively high concentrations on site are for DDD at 220 mg/kg and DDT at 150 mg/kg. There are no acute or sub-chronic reference doses available for these compounds (cancer end points are not considered in acute or sub-chronic exposures). Consultation with Dr. Prince (EPA IRIS Hotline) and Dr. Smucker (EPA R9) indicate that there is not a lot of information on acute reference doses for DDT. General opinion was that at 220 ppm and 150 ppm soil concentrations there should not be an acute problem.

Reference was made to an Agency for Toxic Substances and Disease Registry (ATSDR) document on DDT, DDE, and DDD. Information from this document is used in this risk assessment to help determine if acute exposures might be a concern at Site 85N. This acute evaluation is not meant to quantify acute exposures, but to give an indication if there might be a problem and require a more in-depth evaluation.

Using some of the research results for acute exposure to DDT in the ATSDR report, an acute risk for ingestion will be calculated. Caution should be realized, as the intent is to give an “order of magnitude” estimation for acute toxicity.

Among the species used listed in the ASTDR report for acute exposures are included three primate tests as shown in Table 7-3.

. Table 7-3 – Acute Exposure Data


Using an uncertainty factor of 10 for use of the lowest observed adverse effects level (LOAEL) endpoint, 10 for animal to human, and 10 for human variability, the first line yields an acute reference dose of 0.15 mg/kg-day.

aRfDo = (150 mg/kg-day) / (10 x 10 x 10) = 0.15

Using an uncertainty factor of 10 for human variability, the second line yields an acute reference dose of 1.03 mg/kg-day.

aRfDo = (10.3 mg/kg-day) / (10) = 1.03 mg/kg/day.

Likewise for the third line, an uncertainty factor of 10 for use of the LOAEL endpoint, 10 for animal to human, and 10 for human variability, the first line yields an acute reference dose of 0.15 mg/kg-day.

aRfDo = (150 mg/kg-day) / (10 x 10 x 10) = 0.15

Taking the more conservative value of 0.15 mg/kg-day, an acute ingestion hazard quotient of 0.045 can be calculated as follows.

aHQ = (376 mg/kg) (1 day / year) ( 25 yr) ( 50 mg/day) = 0.045 (70 kg) (1 day) (0.15 mg/kg-day) (1E+06 mg/kg)

376 mg/kg = combined concentrations in soil of DDT, DDE, and DDD 1 day / year = Exposure frequency 25 years = exposure duration 50 mg / day = soil ingestion rate 70 kg = adult body weight 1 day = averaging time 0.15 mg/kg-day = acute reference dose 1E+06 mg/kg = conversion factor

This aHQ of 0.045 is about two orders of magnitude less than the acceptable HQ value of one. The acute reference dose of 0.15 mg/kg-day, while not a published or peer-reviewed figure, allows a determination to be made that acute exposure is not a consideration at this site and chronic exposure controls.

7.4.2 Toxicity Assessment

Published Criteria Used The standard toxicity hierarchy is:

• The Integrated Risk Information System (IRIS); • The Health Effects Assessment Summary Table (HEAST); • EPA Criteria Documents; • ATSDR minimal risk levels (MRLs); and • Other professionally peer reviewed documents as needed and approved by ADEC on a

case-by-case basis.


The IRIS database was contacted directly. HEAST, EPA Criteria Document, and other professionally peer reviewed documents were contacted indirectly through the EPA Region 9 Preliminary Remediation Goals Tables (EPA 2000) and the EPA Region 3 Risk-Based Concentration Tables (EPA 2001). Petroleum fraction reference doses are from ADEC 1999. See Tables 7-4 and 7-5.

Missing Toxicity Factors Noncarcinogenic toxicity factors are missing for benzo(a)pyrene, TCDD, DDE, DDD, and lead. The missing noncarcinogenic reference dose for benzo(a)pyrene was addressed by using the reference dose for pyrene as a surrogate. Likewise, the noncarcinogenic reference doses for DDD and DDE were addressed by using the reference dose for DDT as a surrogate. A noncarcinogenic toxicity factor for TCDD was estimated by taking the RfD for DDT and dividing by four orders of magnitude. This is, at best, a rough approximation. However, it is based on comparing toxicity results on various animals as documented in the National Institutes of Health's National Institute of Environmental Health Sciences (NIEHS) online datasbase < http://ntp-server.niehs.nih.gov/Main_Pages/Chem-HS.html>. While not identical in structure, there are similarities and the molecular weights are close. Lead is addressed separately from this risk assessment. Lead cleanup levels are based on EPA models (IEUBK 1994 and TRW 1996).

Adjustments and Extrapolations None other than the surrogates documented above.


ADEC Human Health Toxicity Data Presentation Table for Carcinogenic Data

Table 7-4 - ADEC Human Health Toxicity Data Presentation Table for Carcinogenic Data (modified)

3.

Cancer Slope Factor

1. Compound of

Concern

2. Citation

Type Value 1/(mg/kg-d)

4. Dermal

Absorption Rate

5. EPA Weight of Evidence

Benzene I I

CSFo CSFi

5.5E-02 2.7E-02

0.0005 A

Benzo(a)pyrene I N, E

CSFo CSFi

7.3E+00 3.1E+00

0.13 B2

DDD I R

CSFo CSFi

2.4E-01 2.4E-01

0.03 B2

DDE I R

CSFo CSFi

3.4E-01 3.4E-01

0.03 B2

DDT I I

CSFo CSFi

3.4E-01 3.4E-01

0.03 B2

Dieldrin I I

CSFo CSFi

1.6E+01 1.6E+01

0.1 B2

Tetrachloroethylene N, E N, E

CSFo CSFi

5.2E-02 2.0E-03

0.03 Not assessed

TCDD, 2,3,7,8- H H

CSFo CSFi

1.5E+05 1.5E+05

0.03 Not assessed

I = IRIS Database accessed 19 DEC 2001. N = NCEA (as documented in EPA R9 PRG Nov 2000 tables). E = NCEA (as documented in EPA R3 RBCT Oct 2001 tables). R = Route Extrapolation (as documented in EPA R9 PRG Nov 2000 tables). H = HEAST (as documented in EPA R9 PRG Nov 2000 tables and EPA R3 RBCT Oct 2001 tables). Dermal absorption rates from EPA R9 PRG Tables and EPA R3 <http://www.epa.gov/reg3hwmd/risk/solabsg2.htm>. EPA Weight of Evidence: A = Human Carcinogen, B2 = Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals. CSFo = oral cancer slope factor. CSFi = inhalation cancer slope factor.


ADEC Human Health Toxicity Data Presentation Table for Noncarcinogenic Data (modified)

Table 7- 5 - ADEC Human Health Toxicity Data Presentation Table for Noncarcinogenic Data (modified)

I = IRIS Database accessed 19 DEC 2001. N = NCEA (as documented in EPA R9 PRG Nov 2000 tables). E = NCEA (as documented in EPA R3 RBCT Oct 2001 tables). R = Route Extrapolation (as documented in EPA R9 PRG Nov 2000 tables). A = ADEC 1999; S = Surrogate (pyrene for benzo(a)pyrene; DDT for DDD and DDE); DDT / 1E+03 for TCDD. Dermal absorption rates from EPA R9 PRG Tables and EPA R3 <http://www.epa.gov/reg3hwmd/risk/solabsg2.htm>. RfDo = oral reference dose. RfDi = inhalation reference dose.

3. Reference Dose

1. Compound of

Concern

2. Citation

Type Value (mg/kg-d)

4. Dermal

Absorption Rate

5. Target organ

6. Uncertainty

Factors

Benzene N N

RfDo RfDi

3E-03 1.7E-03

0.005 Not assessed Not assessed

Benzo(a)pyrene S, I S, R

RfDo RfDi

3E-02 3E-02

0.13 Kidney effects 3000

DDD S, I S, R

RfDo RfDi

5E-04 5.0E-04

0.03 Liver lesions 100

DDE S, I S, R

RfDo RfDi

5E-04 5.0E-04


DDT I R

RfDo RfDi

5E-04 5.0E-04


Dieldrin I R

RfDo RfDi

5E-05 5.0E-05


Tetrachloroethylene I E

RfDo RfDi

1E-02 1.4E-01

0.03 Hepatotoxicity in mice, weight gain in rats

1000

Trichloroethane, 1,1,1-

E E

RfDo RfDi

2.8E-01 6.3E-01

0.005 Withdrawn Withdrawn

TCDD, 2,3,7,8- S, I S, I, R

RfDo RfDi

5.0E-08 5.0E-08

0.03 Not assessed

GRO aliphatics A A

RfDo RfDi

5 5.3

0.03 Neurotoxicity

GRO aromatics A A

RfDo RfDi

0.2 0.1

0.03 Hepatoxicity Nephrotoxicity

DRO aliphatics A A

RfDo RfDi

0.1 0.3

0.1 Hepatic & hematological

changes

DRO aromatics A A

RfDo RfDi

0.04 0.06

0.1 Decreased body weight

RRO aliphatics A

RfDo

2

0.1 Hepatic granuloma

RRO aromatics A

RfDo

0.03

0.1 Nephrotoxicity


7.4.3 Risk Characterization The information from the exposure assessment and the toxicity assessment is integrated to form the basis for the characterization of human health risks.

Carcinogenic Risks For carcinogens, risks are defined as the likelihood of an individual developing cancer over a lifetime as a result of exposure to a chemical. That is, incremental or lifetime excess risk. The incremental lifetime cancer risk is obtained by multiplying the average daily dose over a lifetime by the cancer potency factor. This will represent risk-per-unit dose.

Carcinogenic risk = (Chronic Daily Dose) x (Slope Factor)

The chronic daily dose is determined using the same equations as found in ADEC 1999, EPA 2000, and EPA 1996. The equations have been rearranged to calculate the risks and are found in Table C.2 of Appendix C of this risk assessment.

A weight –of-evidence approach is used by the EPA to classify the likelihood the chemical in question is a human carcinogen. Based on studies, the chemical is placed in one of six groupings. See Table 7-6.

Table 7-6 – Weight of Evidence

Group Category Retain as Carcinogen in Risk

Assessment? A Human Carcinogen yes B1 Probable Human Carcinogen

(Limited Human Evidence) yes

B2 Probable Human Carcinogen (Sufficient evidence in animals, inadequate or no evidence in humans)

yes

C Possible Human Carcinogen Discuss in uncertainty assessment only

D Not Classifiable as to Human Carcinogenicity

no

E Evidence of non-carcinogenicity for humans

no

The chemicals at Site 85N are either Group A, B2, D, or “not available.” See Table 4

and Table C.5 of Appendix C of this risk assessment.


Noncarcinogenic Risks For noncarcinogens, the Hazard Quotient (HQ) is calculated as the average daily dose for the chronic exposure period divided by the chronic reference dose (RfD). Hazard indices are calculated separately for each scenario and for each exposed population.

Hazard Quotient = (Chronic Daily Intake) / (RfD)

The chronic daily intake is determined using the same equations as found in ADEC 1999, EPA 2000, and EPA 1996. The equations have been rearranged to calculate the risks and are found in Table C.2 of Appendix C of this risk assessment.

The non-cancer hazard quotient assumes that there is a level of exposure (i.e., RfD) below which it is unlikely for even sensitive populations to experience adverse health effects. If the exposure level exceeds this threshold (i.e., if the HQ exceeds unity), there may be concern for potential non-cancer effects. As a rule, the greater the value of HQ above unity, the greater the level of concern. However, the HQs and HIs are not statistical probabilities (as opposed to the carcinogenic risks); a HQ of 0.001 does not mean that there is a one in one thousand chance of the effect occurring. It is also important to emphasize that the level of concern does not increase linearly as the RfD is approached or exceeded because RfDs do not have equal accuracy or precision and are not based on the same severity of toxic effects.


Risk Levels A summary of the risks (ELCR = excess lifetime cancer risk; HQ = hazard quotient; HI = hazard index (summation of HQs)) is shown in Table 7-7. Risks are shown for each COC, pathway, and summations.

Table 7-7 – Risk Levels


7.5 Results of Preliminary Problem Formulation and Ecological Effects Evaluation

The preliminary problem formulation and ecological effects evaluation indicate that ecological risk is not an issue at Site 85 North. Rationale for this decision follows below.

7.5.1 Environmental Setting and Contaminants at the Site Site 85N at Fort Greely is located between an active aircraft runway and taxiway. The site is about a half acre in size. Once a year the vegetation is trimmed back using a tractor pulling a brush hog. Photos 7-1 and 7-2 are “on the ground” photographs. Aerial photographs from 1999 are in Section 2 of the REPORT. This particular site is not of high quality habitat for birds, mammals, or amphibians. It is not connected to, or adjacent to any wetland areas. Not only will the noise and activity from the adjacent runway and taxiway discourage wildlife habitation, any large birds or mammals will be actively chased from the area. The ADEC Ecological Checklists are included in Appendix B.

The contaminants on site (and their maximum detected concentrations) are benzene (0.55 mg/kg), benzo(a)pyrene (0.054 mg/kg), DDD (220 mg/kg), DDE (6.2 mg/kg), DDT (150 mg/kg), Dieldrin (0.089 mg/kg), Dioxin (3E-05 mg/kg), Tetrachloroethylene (PCE) (0.177 mg/kg), 1,1,1-Trichloroethane (0.013 mg/kg), GRO (260 mg/kg), DRO (2400 mg/kg), RRO (570 mg/kg), and lead (746 mg/kg). The contaminants are not of a nature to pose an “attractive nuisance” such as antifreeze would with its sweet odor.

7.5.2 Contaminants Fate and Transport The contaminants on site include volatiles and nonvolatiles. The volatile concentrations are such that leaching into groundwater is not a consideration (See Groundwater Considerations). Concentrations of volatiles are low so vaporization is not an ecological pathway. The area is vegetated and particulate emissions are not a factor. The only time that the annual mowing raises any type of visible dust or particulates is if the brush hog hits a stone.

7.5.3 Ecotoxicity and Potential Receptors The risk drivers on Site 85 North are pesticides; in particular DDD and DDT. DDE and Dieldrin are also on site. Pesticides, by their design, are toxic. This is very true when the receptors are birds. Comparing these compounds with other compounds in ORNL 1996 can assess the level of ecotoxicity. Comparing toxicity to terrestrial wildlife, it can be seen that Dieldrin is approximately an order of magnitude more toxic than Heptachlor (Heptachlor is not a COC but included here for comparison purposes only). Heptachlor is about an order of magnitude more toxic than DDT. And DDT is about an order of magnitude more toxic than Toluene (Toluene is not a COC but included for comparison purposes only). Potential receptors are limited to soil organisms. The noise and activity from the adjacent runway and taxiway discourage wildlife habitation; any large birds or mammals will be actively chased from the area. (See Table 7-8)


Table 7- 8 - Ecotoxicity

NOAEL (mg/kg/day) Species DDT Dieldrin Heptachlor Toluene

Rat / Mouse (test species)

0.8 0.02 0.1 26.0

Short-Tailed Shrew 1.76 0.044 0.29 30.9 White-Footed Mouse 1.6 0.04 0.26 28.1 Mink 0.62 0.015 0.1 10.8 Cottontail Rabbit 0.59 0.015 0.096 10.3 Red Fox 0.42 0.011 0.069 7.4 Average 1.0 0.024 0.15 18.9

7.5.4 Completed Exposure Pathways The only completed exposure pathways are to the soil organisms and plants on the half-acre site.

General Assessment and Measurement Endpoints At Site 85 North, there are no endpoints. While soil organisms and plants on the site may be slightly impacted, these are not assessment endpoints. The subpopulations of these organisms will not be effected. The limited size of the site, its location, groundcover, and concentrations of contaminants preclude migration up the food chain.

7.6 Calculations for Alternative Risk-Based Cleanup Levels: Human Health

Where possible, the proposed ACLs are capped at the ADEC regulatory levels (18 AAC 75, Table B). See Table 7-9.

Table 7-9 - ACLs Compound Proposed

ACL (mg/kg)

18 AAC 75 Table B (ingestion, inhalation,

migration to GW)

ELCR at ACL

HI at ACL

Benzene 5 290; 9; 0.02 7.2E-09 0.00 Benzo(a)pyrene 1 1; ---; 3 1.4E-08 0.00 4,4-DDD 300 35; ---; 47 7.1E-08 0.00 4,4-DDE 150 24; ---; 150 5.0E-08 0.00 4,4-DDT 300 24; 5300; 88 1.0E-07 0.00 Dieldrin 0.5 0.5; 8; 0.015 1.5E-08 0.00 Dioxin (2,3,7,8-TCDD) 0.003 case by case 4.7E-07 0.00 Tetrachloroethylene (PCE) 5 160; 80; 0.03 7.5E-10 0.00 1,1,1-Trichloroethane 5 ---; 460; 1.0 0 0.00 GRO aliphatics 270 1000; 1000; 270 0 0.00 GRO aromatics 150 1000; 1000; 150 0 0.00 DRO aliphatics 7200 10000; 10000; 7200 0 0.00


Compound Proposed ACL

(mg/kg)

18 AAC 75 Table B (ingestion, inhalation,

migration to GW)

ELCR at ACL

HI at ACL

DRO aromatics 1000 4100; 5000; 100 0 0.00 RRO aliphatics 20000 20000; 20000; 20000 0 0.00 RRO aromatics 3000 3000; 10000; 3300 0 0.00 Cumulative 7.3E-07 0.01 7.6.1 Comparison of Calculated Risk-Based Concentrations to Regulatory Standards The current (base line) human health risk on site is conservatively calculated as 1.1E-07 for ELCR and 0.00 for HI (Table C.6). These figures are orders of magnitude below the ADEC targets. The recommended ACLs above would yield a cumulative ELCR of 7.3E-07 and a HI of 0.01. This is over an order of magnitude less than the ADEC target of 1E-05. The 18 AAC 75 regulatory criteria was developed for residential scenarios. The scenario at Site 85 North is industrial/commercial with limited exposure.

7.6.2 Consideration of Effects of Leaching to Groundwater The above table shows that only the ACLs for benzene, DDD, DDT, Dieldrin, PCE, Trichloroethane, and DRO aromatics are above the ADEC (18 AAC 75) Method 2 regulatory criteria for migration to groundwater. These regulatory criteria are conservative risk-based levels using an infinite source assumption and homogenous contamination from ground surface to water table assumption. More accurate modeling using SESOIL (See Groundwater Considerations) and negative detection of pesticide contamination in the groundwater-monitoring program indicates that these ACLs will not impact groundwater.

7.6.3 Uncertainty Assessment Data collection and data evaluation and reduction techniques can influence the uncertainty of site risk calculations. There is always a possibility that a compound of concern may have been missed or overlooked. This is especially true when actual information on the chemicals spilled is unknown. Site 85 North is this type of site. The overlooking of a COC may increase the actual risk on site as compared to what was calculated. However, the probability of this happening here is remote and should not impact the calculated site risk. The original list of COPC was extensive and included all the ADEC recommended analytes for an unknown spill plus any compound detected during the investigations at Site 85N plus at Sites 85S and 133 (similar, close by sites). Data evaluation and reduction for the several sampling and analysis events at Site 85 North was rigorous and supports the decisions made. The detection limit issue was re-evaluated to insure that limits were low enough to support actions on site. Investigations at Site 85N began in 1991 and regulatory criteria have evolved since then. This also has impacted the detection limit issue. This re-evaluation supports the claim that the site has been adequately characterized.

The models used during this assessment, other than the reference to other SESOIL modeling, were limited to simple analytical equations. These models are documented in EPA 1996, EPA 2000, and ADEC 1999. Since EPA and ADEC use these models for screening purposes, they are by necessity very conservative. The input parameters are also conservative. The actual exposure frequency for workers on site (1 day per year) was used in


lieu of the standard ADEC exposure frequency parameter (250 days per year). This was the procedure agreed at the risk assessment scoping meeting. Site 85 North is unique in that it is located between an active runway and taxiway. The only exposure is one mowing per year with a tractor and brush hog. The one day per year is in itself conservative as to mow Site 85N will take less than half an hour. Using the one day per year figure yields a higher risk than the actual.

Uncertainty in the Toxicity Assessment can impact the risk calculations. EPA uses standard uncertainty factors in determining chemical cancer slope factors and reference doses. The standard uncertainty factors (UF) are:

An UF of 10 is used to account for variation in the general population and is intended to protect sensitive subpopulations (e.g., elderly, children). Since Site 85N is industrial in nature, this UF adds an extra layer of conservatism. An UF of 10 is used when extrapolating from animals to humans. This factor is intended to account for the interspecies variability between humans and other mammals. An UF of 10 is used when a no observable adverse effects level (NOAEL) derived from a subchronic instead of a chronic study is used as the basis for a chronic RfD. An UF of 10 is used when a LOAEL is used instead of a NOAEL. This factor is intended to account for the uncertainty associated with extrapolating from LOAELs to NOAELs.

The use of surrogates for chemicals that do not have toxicity data adds uncertainty to the assessment. This assessment uses the reference dose for DDT for DDD and DDE. Likewise, the reference dose for pyrene is used for benzo(a)pyrene. The use of surrogates of a similar structure and properties will keep these uncertainties low. Dioxin is one of the more toxic chlorinated compounds. No RfDs are available. For this assessment, the RfDs for DDT were divided by four orders of magnitude. This is, at best, a rough approximation. However, it is based on comparing toxicity results on various animals as documented in the National Institutes of Health's National Institute of Environmental Health Sciences (NIEHS) online datasbase < http://ntp-server.niehs.nih.gov/Main_Pages/Chem-HS.html>.

Every risk assessment has uncertainties. However, those in this assessment do not overshadow the conservative approach used to calculate the on-site risks, thus the uncertainties are minimized. Utilization of surrogates reduces the assessment uncertainty as compared to not including conmpounds without published toxicity factors.

7.6.4 Endocrine Disruptors Endocrine disruptors are chemicals that interfere with endocrine system function. An endocrine system is found in nearly all animals, including mammals, non-mammalian vertebrates (like fish, amphibians, reptiles, and birds), and invertebrates (like snails, lobsters, insects, and other species). The endocrine system consists of glands and the hormones they


produce that guide the development, growth, reproduction, and behavior of human beings and animals. Some of the endocrine glands are the pituitary, thyroid, and adrenal glands, the female ovaries and male testes. Hormones are biochemicals, produced by endocrine glands that travel through the bloodstream and cause responses in other parts of the body. The EPA is initiating an Endocrine Disruptor Screening Program that will focus on the estrogen, androgen and thyroid hormones.

The term organochlorine refers to chemical compounds that have a chlorinated hydrocarbon structure, that is, they are formed from atoms of hydrogen, carbon, and chlorine. Although their effect may be much weaker than the body’s natural hormones (like estrogens, androgens, and thyroid hormones), they are nonetheless suspected of disrupting the endocrine system, resulting in harmful effects like reproductive and developmental defects and certain cancers. EPA has banned PCB’s, dieldrin, DDT, chlordane, aldrin, kepone, mirex, endrin, and toxaphene. Organochlorine pesticides still registered for use in the United States include endosulfan, lindane, methoxychlor, dicofol, dienochlor, and heptachlor. However, their use is very restricted and most are scheduled for priority pesticide re-registration review. They will likely be among the first compounds to be screened in the Endocrine Disruptor Screening Program.

Site 85 North has potential endocrine disruptors in its soil. These include DDT, DDE, DDD, and dieldrin. As such, there is the possibility that the actual site risks may be underestimated. Until further research is completed and the EPA program progresses, the amount of impact, if any, will not be known. The restricted area and exposure (exposure frequency and vegetated top cover) will help minimize any contact with these chemicals.


7.7 References

ADCED 2001, Alaska Department of Community and Economic Development, “Alaska Community Information Summary – Fort Greely,” http://www.dced.state.ak.us/mra/CF_CIS.htm, accessed 19 November 2001.

ADEC 1999, Alaska Department of Environmental Conservation (ADEC), “Guidance on Cleanup Levels Equations and Input Parameters,” July 28, 1999.

ADEC 2000a, Alaska Department of Environmental Conservation (ADEC), “Risk Assessment Procedures Manual,” June 8, 2000.

ADEC 2000b, Alaska Department of Environmental Conservation (ADEC), “Guidance for Cleanup of Petroleum Contaminated Sites,” September 2000.

AGRA 1998, AGRA Earth and Environmental, Inc., “Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska, Submittal 002 – Final,” July 1998.

ESHT 2000, Robert A. Haviland, Marlowe Dawag, and David T. Hanneman, “Selecting Indicator and Surrogate Compounds,” in Jay H. Lehr (ed.), Standard Handbook of Environmental Science, Health, and Technology, McGraw-Hill, New York, 2000, p. 12.18.

EPA 1989, U.S. Environmental Protection Agency (EPA), “Risk Assessment Guidance for Superfund,” Volume I: Human Health Evaluation Manual (Part A), Interim Final, EPA/540-1-89/002, December 1989.

EPA 1996, U.S. Environmental Protection Agency (EPA), “Soil Screening Guidance: User’s Guide,” EPA/540/R-96/018, April 1996.

EPA 2000, U.S. Environmental Protection Agency (EPA) Region 9, “Region 9 Preliminary Remediation Goals (PRGs) 1999,” November 1, 2000.

EPA 2001, U.S. Environmental Protection Agency (EPA) Region 3, “Risk-Based Concentration Table,” September 25, 2001.

JEG 2001, Jacobs Engineering Group, Inc. (JEG), “Limited Risk Evaluation, Fort Greely, Alaska,” November 2001 (with subsequent technical memorandums).

ORNL 1996, Oak Ridge National Laboratory, “Screening Benchmarks for Ecological Risk Assessment,” version 1.6, October 1996.

USACE 1994, United States Army Corps of Engineers (USACE), “Site Assessment / Corrective Action Plan, Three Former Fire Training Pits, Fort Greely, Alaska,” March 7, 1994.


USACE 2001a, United States Army Corps of Engineers (USACE), “Source Water Assessment: Fort Richardson, Alaska, Fort Wainwright, Alaska, Fort Greely, Alaska,” August 2000.

USACE 2001b, United States Army Corps of Engineers (USACE), “REPORT, Soil Screening Evaluation, Fort Greely BRAC, Site 85 South, Site 85 North, Site 133, Site 112,” Draft, August 2001.

USACE 2001c, “Scoping Meeting USARAK Fort Greely Site 85N Risk Assessment,” minutes, 24 OCT 2001.

USACE 2002a, “Current and future maintenance at Site 85N.” Telephone conversation Robert Haviland (USACE) and Dean Stumpe (USARAK DPW), 9 NOV 2001.

USACE 2002b, “Fort Greely Site 85N Risk Assessment Workplan Annotated Comments,” email to Greg Light (ADEC) and Stephanie Pingree (ADEC) from Robert Haviland (USACE), 6 February 2002.


APPENDIX 7-A – TOXICOLOGICAL PROFILES

The major risk drivers on Site 85 North are DDT and DDD.


APPENDIX 7-B - ADEC ECOLOGICAL CHECKLIST

FIGURE B.1 – ECOLOGICAL CHECKLIST #1: GENERAL


FIGURE B.2 – ECOLOGICAL CHECKLIST #2: TERRESTRIAL


FIGURE B.3 – ECOLOGICAL CHERCKLIST #3: AQUATIC-FLOWING SYSTEMS

None on site.

FIGURE B.4 – ECOLOGICAL CHECKLIST #4: AQUATIC NON-FLOWING SYSTEMS

None on site.

FIGURE B.5 – ECOLOGICAL CHECKLIST #5: WETLANDS


APPENDIX 7-C – MODELING INPUTS

TABLE C.1 - HUMAN HEALTH COMPOUNDS OF POTENTIAL CONCERN ADEC DATA PRESENTATION

ENVIRONMENTAL MEDIUM: Surface Water Groundwater Air

X Soil Sediment Biota

Detected Parameter Units Detection Frequency

Reported Concentrations (Minimum and maximum concentrations are

highlighted.)

Detection Limits (varies by reference)


ADEC 18 AAC 75 Method 3 Cleanup Level

Ingestion Inhalation

Migration GW

Detection Frequency

above Cleanup Level

PETROLEUM HYDROCARBONS (FUELS) Gasoline Range Organics (GRO)

mg/kg 19 / 28 [1996-1997] 1.9, 1.9, 0.88, 9.5, 1.3, 1, 2.2, 1.4, ND, ND, ND, 0.65, ND, 1.5, 3.9, 0.76, 0.37, ND, 0.6, ND, 4.9 [1998] 1, ND, ND, 4, 260, 29, ND

[1996-1997 - 0.32 - 0.98] [1998 - 5]

- 1400 Csat 1400 Csat

300

0 / 28 0 / 28 0 / 28

Diesel Range Organics (DRO)

mg/kg 26 / 27 [1996-1997] 670, 600, 620, 630, 750, 520, 380, 860, 470, 970, 560, 620, 440, 780, 140, 200, 330, 190, 110, 140, 400, [1998] 27, ND, 298, 2400, 1700, 3J

[1998 - 4] <68 *3 10250 12500 Csat

250

0 / 27 0 / 27 19 / 27

Residual Range Organics (RRO)

mg/kg 3 / 6 60J, ND, 570, 110, ND, ND 100 - 10000 22000 Csat

11000

0 / 6 0 / 6 0 / 6

VOLATILES Benzene (ca) mg/kg 17 / 118 [1991] 10 @ ND (0.005-0.006) for toluene, no benzene

results reported; [1992] 45 @ ND (0.0026-0.0027); 1 ND (0.026), 0.0028, 0.0094, 0.0066, 0.0022J, 0.0053, 0.0084, 0.018, 0.029 {Sample [email protected]'-26.5'}, 0.045 {Sample [email protected]'-21.5'}, 0.091{Sample [email protected]'-3.5'}, 0.550 {Sample [email protected]'-5.5'}; [1994] 15 @ ND (0.012-0.013), 2 ND (0.0038), 0.001J, 0.0027, 0.0005J, 0.0004J, 0.00073, 0.00044; [1995] 3 @ ND (0.0021), 1 ND (0.0053); [1996-97] 21 @ ND (0.0084-0.02); [1998] 6 @ ND (0.05), 1 ND (0.1)

See detection limits in "Reported


- 290 9

0.02

0 / 118 0 / 118 4 / 118




highlighted.)





Migration GW

Detection Frequency

above Cleanup Level

Toluene (S) mg/kg 2 / 27 24 @ ND, 0.030, 0.05J 0.024 - 0.1 ND - 0.08 *3 20300 180 Csat

5.4

0 / 27 0 / 27 0 / 27

Ethylbenzene (ND) mg/kg 0 / 28 28 @ ND 0.015 - 0.1 - 10000 89 Csat

5.5

0 / 28 0 / 28 0 / 28

Xylenes (total) (S) mg/kg 3 / 28 25 @ ND, 0.045, 0.029, 0.03J 0.05 - 0.1 - 203000 81 Csat

78

0 / 28 0 / 28 0 / 28

Methylene chloride (ca) mg/kg 8 / 17 [1991] 0.006B, 0.013B, 0.002J, 0.007, 0.007, 0.008, 0.006, 0.007, ND (0.005), ND (0.010); [1998] 6 ND (0.1), 1 ND (0.2)

1100 180

0.015

0 / 17 0 / 17 0 / 17

Tetrachloroethylene (PCE) (ca)

mg/kg 5 / 18 [1991] 6 @ ND (0.005-0.006), 0.001J, 0.003J, 0.009, 0.076 {Sample no. 9129GFTP059SL}; 0.177 {Sample no. 9129GFTP059SL}; [1998] 6 @ ND (0.05), 1 ND (0.10 UJ-H)

[1991-0.005-0.006] [1998 - 0.05-0.1)

160 80 Csat

0.03

0 / 18 0 / 18 2 / 18

1,1,1-Trichloroethane mg/kg 1 / 18 [1991] ND, ND, 0.013, ND, ND, ND, ND, ND, ND, ND, ND [1998] 7 @ ND

0.005 - 0.1 --- 460 Csat

1.0

--- 0 / 18 0 / 18

SEMIVOLATILES Benzo(a)pyrene (ca) mg/kg 1 / 18 [1998] 6 @ ND (0.3); [1996] 11 @ ND (0.01), 0.054; [1994]

19 @ ND (0.05), 3 @ ND (.220) 0.01 - 0.3 1

--- 3

0 / 18 ---

0 / 18 Chrysene (ca) (S) mg/kg 1 / 18 17 @ ND, 0.040 0.029 - 0.3 1100

--- 620

0 / 18 ---

0 / 18 Fluoranthene (S) mg/kg 1 / 18 16 @ ND, 0.027J 0.025 - 0.3 4100

--- 2100

0 / 18 ---

0 / 18




highlighted.)





Migration GW

Detection Frequency

above Cleanup Level

Pyrene (S) mg/kg 4 / 18 0.036, ND, ND, 0.053, 0.065, ND, 0.029, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

0.028 - 0.3 3000 ---

1500

0 / 18 ---

0 / 18 Dibenzo(a,h) Anthracene (ca) (nd)

0 / 18 [1998] 6 @ ND (0.3); [1996] 12 @ ND (0.01) 1 --- 6

0 / 18 ---

0 / 18

PESTICIDES / INSECTICIDES 4,4-DDD (ca) mg/kg 76 / 175 [1991] ND, ND, 18, 81, 0.065, ND, ND, ND, ND, ND

[1992] ND, ND, 0.013, ND, ND, ND, 0.0077, 140, 46, ND, ND, 0.015, ND, 0.0061, 0.160, 0.0032, ND, ND, ND, 0.010, 0.0093, ND, ND, ND, ND, 0.0032, ND, ND, ND, ND, 0.0061, 0.0061, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND (34) {Sample no. 92GFTP019SL(surface)}, ND (34) {Sample no. 92GFTP252SL(replicate)}, 3.9, ND, ND, ND, ND, ND, ND, ND, ND, ND, 220, 170, ND, ND, ND, 0.320, ND, ND, 0.015, 0.94, 0.54, 0.93, ND, ND, 2.1, ND, ND, 9.4, ND, ND, ND, ND, ND, ND, 0.3, ND, 2.1, ND, ND, [1994] 0.0052, 0.0046, ND, ND, 0.0049, 0.0047, ND, ND, 0.0096, 0.0046, 0.130, 0.0017, ND, ND, ND, ND, 0.099, 16, 82, 6.7, 2.2, 0.0089, 20, [1995] 29, 18, 16, ND, ND, [1996-1997] 16, 33, 17, 20, 27, 27, 38, 30, 22, 17, 6.5, 16, 20, 30, 32, 22, 28, 53, 19, 2, 1.8, 4.7, 10, 5, 7, 6.9, 1.7, [1998] 0.012, ND, 0.23, 1.3, ND, ND

[1991-0.010-0.0338]

[1992-0.003-16.5(except 2

samples with DL of 34 - see under

reported concentrations)] [1994-0.00096-

0.0011] [1998-0.010]

35 --- 47

8 / 175 ---

6 / 175

4,4-DDE (ca) mg/kg 58 / 175 [1991] ND, ND, 1.5, 2.9, 0.19, ND, ND, ND, ND, ND, [1992] 2.3, 0.51, 0.17, 1.9, 6.2, 0.37, 0.04, 0.87, 0.75, 0.77, 1.2, 0.37, 0.019, 0.310, 1 ND (34) {Sample no. 92GFTP019SL(surface)}, 1 ND (34) {Sample no. 92GFTP252SL(replicate)} plus 88 @ ND; [1994] 0.0057, ND, ND, ND, 0.0081, 0.014, ND, ND, 0.0044, ND, 0.011, ND, 0.011, ND, ND, ND, 0.0075, 2.2, ND, ND, ND, ND, 1.6, [1995] 2.1, 1.2, 2.1, [1996-1997] 0.57, 0.96, 0.89, 1.4, 3.2, 2.1, 1.4, 1.1, 1.7, 0.6, 0.54, 1.3, 0.74, 1.6, 1.7, 0.83, 2.5, 2.4, 0.23, 0.18, 0.2, 0.35, 0.53, 0.48, 0.40, 0.64, 0.38, [1998] ND, ND, 0.081, 0.094, ND, ND

[1991-0.010-0.0357]

[1992-0.0030-16.5(except 2

samples with DL of 34 - see under

reported concentrations)]

[1994-0.00096-2.6] [1998-0.010]

24 ---

150

0 / 175 ---

0 / 175




highlighted.)





Migration GW

Detection Frequency

above Cleanup Level

4,4-DDT (ca) mg/kg 135 / 175 [1991] ND, ND, 39, 150, 0.84, ND, 0.013, ND, ND, 0.1, [1992] 0.39, 0.018, 0.007, 0.032, ND, 0.0052, ND, 130, 34, 0.14, 5.7, 0.029, ND, 0.011, 0.17, 0.011, 0.25, 0.59, ND, 0.017, 0.011, 0.005, 0.013, 8.5, 0.046, ND, ND, ND, 0.037, ND, 0.0079, 0.0084, 0.054, 0.063, ND, ND, ND, ND, ND, 0.52, ND, ND, 0.0039, ND, ND, ND, 4, 0.0057, 0.086, 0.210, ND, 0.0058, 0.0078, 0.021, 0.014, 0.012, ND, 0.051, 0.027, ND, ND, 0.059, ND, 67, 47, 40, 19, 25, 10, 1.5, 1, 1.1, 19, 22, 23, 85, 51, 48, 10, 4.1, 1.4, 0.21, 0.25, 0.22, 3.2, 3.1, 4.3, 20, 26, 8.6, 43, 42, 24, 0.054, 0.11, 0.14, 6, 4.3, 4.3, 3, 5.9, ND, 21, 10, [1994] 0.049, 0.0028, ND, ND, 0.058, 0.1, ND, ND, 0.035, 0.0021, 0.11, 0.0019, 0.12, ND, ND, ND, 0.09, 22, 33, 29, 19, 0.034, 8.1, [1995] 65, 33, 130, [1996-1997] 10, 24, 71, 39, 40, 36, 36, 38, 41, 26, 8.4, 19, 12, 30, 17, 15, 39, 46, 2.8, 2.7, 3.1, 6.9, 15, 5.1, 7.1, 8.9, 4.9, [1998] 0.035, ND, 0.42, 10, 0.015, 0.006

[1991-0.0162-0.0334]

[1992-0.0030-16.5] [1994-0.00096-

0.0011]

24 5300

88

29 / 175 0 / 175 3 / 175

Dieldrin (ca) mg/kg 2 / 173 [1991] 1 ND (0.010), 1 ND (0.0162), 6@ND (0.0324-0.0338), 1ND(1.64) {Sample no. 9129GFTP078SL}, 1 ND (20.4) {Sample no. 9129GFTP079SL}; [1992] 46 @ ND (0.015 or lower - subsurface), 12@ND (0.031-3.2 - subsurface), 18 @ ND (0.08 - 82.5 - surface); [1994] 18 @ ND (0.00095-0.0051), 2 @ ND (0.40) {Sample no. B-MP3-S1 & B-MP3-S6 (dup)}, 1 ND (0.98) {Sample no. B-MP3-S4}, 1 ND (1.0) {Sample no. B-MP3-S3}, 1 ND (2.6) {Sample no. B-MP3-S2}; [1995] 2 @ ND (0.32) {Sample no. 4B-B3-01 & 4B-B3-07}, 1 ND (0.006) {Sample no. 4B-B3-10-NPD -triplicate sample}, [1996-1997] 1 ND (0.002), 14 @ ND (0.02-0.10), 3 @ ND (0.48-0.51), 6 @ ND (0.97-1.0), 1 ND (2.3), 0.089, 0.045; [1998] 6 @ ND (0.010)



0.5 8

0.015

0 / 173 0 / 173 2 / 173

POLYCHLORINATED BIPHENYLS Total PCBs (ca) (nd) mg/kg 0 / 79 [1991] 8 @ ND (0.08-0.34), 1 ND (8.2-16.4) {Sample no.

9129GFTP078SL}, 1 ND (102.2-204.3) {Sample no. GFTP079SL}; [1992] 3 @ ND (2.4-8.8), 3 @ ND (9.8-20), 6 @ ND (22-95), 6 @ ND (104-890), 2 @ ND (920-2175); [1998] 6 @ ND (0.1)



1 residential 10 industrial

0 / 79 0 / 79




highlighted.)





Migration GW

Detection Frequency

above Cleanup Level

DIOXINS / FURANS 2,3,7,8 TCDD Equivalent (2,3,7,8-Tetrachlorodibenzo-p-Dioxin ) (TEF or TEQ) (ca)

mg/kg 21 / 26 [1992] ND, ND, ND, ND, 1.29x10-5, 7.3x10-6, 1.8x10-6, 3.7x10-7, 3.4x10-7, 4.2x10-7, 5.5x10-6, 6.3x10-6, 1.8x10-6, 3x10-5, 1.7x10-5, 3.5x10-6, 1.2x10-5, ND, 1.2x10-5, 3.4x10-6, [1998] 7.57x10-6, 5.77x10-6, 3.23x10-6, 3.83x10-7, 1.56x10-7, 1.36x10-7

METALS RCRA Metals

Arsenic (ca) (BK) mg/kg 16 /16 [1991] 4.1-13 [1998] 4-8 4 - 40 *3 9.6 *4

5.5 --- 2

Barium (BK) mg/kg 16 /16 [1991] 53.2-127 [1998] 56-177 43 - 651 *3 678 *4

7100 ---

1100

Cadmium (BK) mg/kg 0 / 16 [1991] ND (1.0) [1998] 1.0 ND [0.10 - 0.13] *30.79 *6

100 --- 5

Chromium (7) (BK) mg/kg 16 /16 [1991] 5.8-25 [1998] 9-23 8 - 43 *3 64 *4

510 --- 26

Lead mg/kg 100 /100 [1991] 3.5-29 [1992] 3.4-66 (subsurface) [1992] 8.6-746 (surface) [TCLP on totals >100 range 0.003-0.79] [1998] 4-21

5 - 69 *3 14 *4

400 residential 1000 industrial

--- 0 / 100

Mercury (BK) mg/kg 0 / 16 [1991] ND [1998] 0.1 - 0.2 0.09 *5 --- 18 1.4

Selenium (BK) mg/kg 4 / 16 [1991] ND [1998] 0.8-1 1 0.3J - ND [1] *3 0.39 *5

510 --- 3.5

Silver (BK) mg/kg 0 / 16 [1991] ND [1998] 2 0.33 *6 510 --- 21




highlighted.)





Migration GW

Detection Frequency

above Cleanup Level

Other Metals Aluminum (BK) mg/kg 16 /16 [1991] 3550-15700 [1998] 6550-9110 65,000 *4 Antimony (BK) mg/kg 4 / 16 [1991] ND [1998] 0.6J-0.7J 1-12 0.66 *5 41

--- 3.6

Beryllium (ca) (BK) mg/kg 1 / 16 [1991] ND [1998] 0.2J 1 1.35 *4 1.9 --- 42

Calcium (BK) mg/kg 16 /16 [1991] 1140-2800 [1998] 1940-12100 20,000 *4 Cobalt (BK) mg/kg 16 /16 [1991] 3.5-8 [1998] 6-9 14 *4 Copper (BK) mg/kg 16 /16 [1991] 13.3-28 [1998] 15-32 29 *4 Iron (BK) mg/kg 16 /16 [1991] 8070-24800 [1998] 14500-18100 38000 *4 Magnesium (BK) mg/kg 16 /16 [1991] 2320-5540 [1998] 4720-5940 12000 *4 Manganese (BK) mg/kg 16 /16 [1991] 202-331 [1998] 290-556 670 *4 Nickel (BK) mg/kg 16 /16 [1991] 10.3-30 [1998] 15-22 33 *4 2000

--- 87

Potassium (BK) mg/kg 16 /16 [1991] 664-1570 [1998] 967-2000 13000 *4 Sodium (BK) mg/kg 16 /16 [1991] 273-418 [1998] 106-193 15000 *4 Thallium (BK) mg/kg 2 / 16 [1991] ND [1998] 0.1J 1 - 2 0.25 *6 Vanadium (BK) mg/kg 16 /16 [1991] 13.6-43 [1998] 25-34 129 *4 710

--- 3400

Zinc (BK) mg/kg 16 / 16 [1991] 21.6-42 [1998] 33-39 79 *4 30000 ---

9100

NOTES:

1) Not all nondect (ND) parameters are shown in table. 2) Footnote *3 = Jacobs Engineering Group (August 2000) Summary Report 1999 Remedial Investigation / Removal Acton, Fort Greely, Alaska.


3) Footnote *4 = United States Geological Survey (USGS) Professional Paper 1458, “Element Concentrations in Soils and Other Surficial materials of Alaska,” 1988. 4) Footnote *5 = USGS Professional Paper 1270, “Element Concentrations in Soils and Other Surficial Materials of the Conterminous United States,” 1984. 5) Footnote *6 = United States Department of Agriculture, Forest Service, “A Summary of Background Concentrations for 17 Elements in North American Soils,”

February 1990. 6) ca = carcinogenic compound 7) Csat = estimated soil saturation concentration. 8) B = analyte found in associated blank as well as in sample. 9) J = value is estimated and below quantitation limit. 10) U = compound was analyzed for, but not detected. 11) BK = concentration within background range.


HUMAN HEALTH CALCULATION EQUATIONS AND PARAMETERS

The following equations and parameters are used to determine the human health risks on Site 85N. Equations were taken either directly from, or modified from, the standard equations found in the EPA 1996, EPA 2000, and ADEC 1999.

TABLE C.2 - RISK EQUATIONS


TABLE C.3 - RISK EQUATION PARAMETERS


TABLE C.4 - PHYSICAL CHEMICAL DATA (PC Data)


TABLE C.5 - TOXICITY INFORMATION


TABLE C.6 - INDUSTRIAL RISK AND HAZARD


APPENDIX 7-D – HUMAN HEALTH CONCEPTUAL SITE MODEL (CSM)


8.0 SITE 133

8.1 Site Location and Background – Site 133

Site 133 is a former fire training area, and was previously referred to as “GFTP-4D” in documentation prior to BRAC work. Site 133 is located south of the aircraft parking apron, and south of 6th Avenue as it parallels the taxiway of Allen Army Airfield (Figure 1-1). Photo 8-1 shows Site 133 on 16 August 2000. Figure 8-1 shows the approximate locations of investigation activities that have been conducted at the site.

Based on USAED (1994) Site Assessment/Corrective Action Plan Three Former Fire Training Pits, Fort Greely, Alaska, Site 133 consisted of several distinct sections early on, including a grassy field, an area containing concrete fill, a forested area, a raised circular area approximately six inches high by five feet in diameter, and a pit six feet deep extending approximately 20 feet by 30 feet. The report indicates these features were visible on aerial photographs and were recognizable during 1991 fieldwork.

The following site history summary is based on the AGRA Earth & Environmental, Inc. (AGRA) report titled Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska dated July 1998 (AGRA 1998). Ecology & Environment, Inc. (E&E) conducted a soil boring and sampling program in 1991 and 1992 at sites designated GFTP-4D East and GFTP-4D West. Contamination was identified at the sites. Because contamination at GFTP-4D East was very limited in extent, the impacted material at this site was moved to the GFTP-4D West location (Site 133) for remedial action. Fuel products and pesticides were found at Site 133 to a depth of 6.5 feet.

Between 1995 and 1997, AGRA developed and performed insitu landfarming at Site 133 to a depth of five feet bgs. Landfarming at Site 133 consisted of berming the site, tilling soil inside the bermed area, and installing and operating an irrigation system. Tilling was accomplished by digging and backfilling a series of trenches across the site. The trenches, advanced to a depth of approximately five feet bgs, were backfilled with the excavated soil. The irrigation system consisted of piping and a pump that transferred water from Jarvis Creek to the site. Soil samples were collected from the landfarmed soil intermittently during the treatment process.

After completion of the landfarming effort, and based on monitoring results from that work, AGRA recommended further work at the site be focused on obtaining closure based on an updated assessment of the risk posed by the documented contaminant levels. AGRA also concluded the data did not support further operation of the remediation system, and recommended collecting confirmation samples.

Sampling was conducted at Site 133 during 1998 under the BRAC LRI program. This work included conducting an initial site evaluation, drilling soil borings, collecting soil samples, and conducting field screening. The bermed landfarm area remains in place at Site 133, but is not actively tilled.


8.2 Identified Documentation and Past Site Activity– Site 133

The following identified documents provide information about Site 133. Selected items of supporting documentation are included in Appendix 133.


2. August 1992, Ecology and Environment, Inc. Fire Training Pits Work Plan, Part 1, Fort Richardson and Fort Greely, Alaska. Document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 133 is referred to as “GFTP4D”.

3. August 1992, Ecology and Environment, Inc. Fire Training Pits Work Plan, Part 2, Subsurface Exploration Plan, Fort Richardson and Fort Greely, Alaska. Document provides a work plan for investigations of fire training pits at Fort Richardson and Fort Greely, Alaska. In this document, Site 133 is referred to as “GFTP4D”.

4. March 7, 1994, USAED. Site Assessment/Corrective Action Plan, Three Former Fire Training Pits, Fort Greely, Alaska. This report documents investigation activities at the site. The document also presents the results of the investigation work conducted by E&E associated with the 1992 work plans referenced above. The document presents a hazard assessment and a corrective action plan. Section 5 of the document, titled “Soil Cleanup Levels” describes the process and results calculating risk-based screening levels under an industrial/commercial scenario for BNA, pesticides, and dioxin.

5. April 1994, USAED. Environmental Assessment and Finding of No Significant Impact, Remedial Treatment of Petroleum Contaminated Soils, Fire Training Pits, Fort Greely, Alaska.

6. May 1995, AGRA Earth & Environmental, Inc. Final Remedial Design Report, Contract No. DACA85-94-D-0011, Fire Burn Pits Treatment System, Fort Greely, Alaska. This report presents a design for performing insitu bioremediation at the site. The design consisted of consolidating GFTP4D East and GFTP4D West at the location of GFTP4D West, then conducting enhanced passive landfarming of soils.

7. July 1998, AGRA Earth & Environmental, Inc. Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska. The report summarizes the activities and findings of the design, installation, and operation of the enhanced passive landfarming treatment system at the site.

8. April 1999, Jacobs Engineering Group Inc. 1998 Remedial Investigation Report, Fort Greely, Alaska, Final. Section 18.0 of this report presents the methodology and results of additional investigation activities conducted at the site under the 1998 BRAC LRI field program.

9. Radian International / Jacobs Engineering Group Inc. Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska, Final. Section 3.5.4 of the report summarizes the affect of additional background investigation on COPCs for the site.


8.2.1 Pre-BRAC Investigation Activities E&E conducted sampling in 1991. The work included the following.

• Two borings were drilled (AP-536, AP-537) at GFTP-4D West (Site 133) to 15.6 and 15.3 feet deep, respectively. Drilling footage was 30.9 feet.

• One boring was drilled (AP-538) at GFTP-4D East, to 15 feet deep. • Soil samples were collected, generally at 4.5, 9.5, and 14.5 feet bgs. • Soil samples were analyzed for VOC, BNA, Fuel Identification (8015 Modified),

pesticides, PCBs, dioxin/furan, and metals.


• Two borings were drilled (AP-598 and AP-600) at GFTP-4D East. • Eleven borings were drilled (AP-601, AP-602, AP-603, AP-604) at GFTP-4D West

(Site 133). Depths of drilling ranged from 11.3 to 31.5 feet bgs. Total drilling footage was 129.3 feet.

• Nine surface soil samples were collected. • Selected soil samples were analyzed for BTEX, Fuel Identification, DRO, (total lead,

TCLP lead, pesticides, PCBs, BNA, and dioxin/furan). • Three sieve analyses were conducted.

AGRA designed, installed, operated, and monitored a landfarming treatment system at the site from 1995 through 1997. The work included the following.

• The upper five feet of impacted soil in the former fire training pit area was landfarmed by trenching, irrigating, turning, and backfilling.

• Soil samples were collected from the tilled material at the site intermittently during landfarm operation.

• Selected soil samples were analyzed for DRO, GRO, BTEX, PAH, and pesticides.


8.2.3 1998 Investigation Activities JEG drilled and sampled the site in 1998. The work included the following.

• One soil borings were drilled (AP-922) to 11.5 feet deep at Site 133 inside the bermed former landfarm area.

• Ten surface soil samples were collected inside the bermed landfarm area. • Selected soil samples were analyzed for DRO, RRO, GRO, VOC, SVOC, pesticides,

PCBs, and metals.

8.2.4 1999 Investigation Activities Activities were not conducted at the site during 1999 BRAC efforts. However, additional background sampling results did affect the COPCs for the site.


8.3 Potential Contaminants

During investigation programs at the site, potential contaminants were identified based on the former use of the site and results of initial investigation activities. The analytical programs for samples collected from the site included analyses for:

• POL organic ranges – GRO, DRO, RRO, Fuel Identification [fuels used during fire training];

• VOCs [constituents of fuels used during fire training];

• SVOCs [constituents of fuels used during fire training];

• Pesticides [possible compounds mixed in fuels used during fire training];

• PCBs [possible compounds contained in fuels used during fire training i.e. old transformer oil];

• Metals [possible compounds contained in fuels used during fire training – i.e. used oil]; and

• Dioxins/furans [possible combustion products from compounds contained in fuels used during fire training].

8.4 Synopsis of Contaminant Distribution – Site 133

8.4.1 Pre-Remedial Action This description is based on the findings of work conducted prior to, and in the early part of, remedial action work (work by E&E and AGRA through May 1996).

Contaminants were detected in samples collected from the surface and subsurface in the former fire training area. The following contaminant types were identified:

• POL fuels (DRO, GRO, and RRO ranges); Detected in surface samples. Detected in subsurface samples to 6.5 feet bgs.

• Pesticides (4,4-DDD, 4,4-DDE, 4,4-DDT); Detected in surface samples. Detected in subsurface samples to 6.5 feet bgs.

8.4.2 Late and Post Remedial Action Descriptions of analytical results from activities conducted during late remedial action and BRAC activity (work after May 1996 by AGRA and JEG) are provided in the reporting documents associated with those activities. A summary follows.

Contaminants were detected in samples collected from the surface and subsurface in the bermed landfarming area. The following contaminant types were detected at concentrations exceeding regulatory levels at the time of the work:

• POL fuels (DRO, RRO); Detected in near-surface samples (upper 2 feet).

• Pesticides (4,4-DDD, 4,4-DDE, 4,4-DDT); Detected in near-surface samples (upper 2 feet). DDT detected in subsurface sample at 10-11.5 feet bgs.


8.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 85 North

A pre-evaluation human health conceptual site model is described below. This description reflects conditions and pathways prior to conducting the ADEC Method Three evaluation. The results of the ADEC Method Three evaluation modify the conceptual site model to that described in Section 8.11.

8.5.1 Contamination Source(s) The contamination source is impacted soil. Surface water does not exist on site. Groundwater is estimated to exist approximately 170 feet below the ground surface at the site.


• Petroleum (GRO, DRO, RRO); • Volatile organic compounds; • Semivolatile organic compounds (including PAHs); • Pesticides; • Dioxin (TEQ); and • Metals.

Based on background sampling conducted under the BRAC program, metals concentrations are attributed to background levels.



Soil Transport Via Erosion and Dispersion: [Incomplete]. The impacted area is roughly flat and grass-covered. See Photo 8-1. The contaminant area is surrounded by berm.

Migration to Groundwater and Groundwater Transport: [Potentially complete]. Some analyte concentrations exceed published migration to groundwater criteria. Migration to groundwater and groundwater transport are considered “potentially complete” exposure pathways, unless/until documented by further evaluation to be incomplete.

Runoff to Surface Water or Surface Sediment, Surface Water Transport: [Incomplete]. The nearest surface water feature is Jarvis Creek (approximately 3000 feet to the east). Based on site reconnaissance, drainage channels flow east from the site and end prior to reaching Jarvis Creek. The site area run-off infiltrates prior to reaching Jarvis Creek.

8.5.3 Migration Pathways

Recognized potential migration pathways consist of:


near the contaminated area at the site); • Excavation (potential future activity);


• Fugitive dust via contaminant dispersion (note the contaminated area is currently vegetated, however future site work could remove or disturb vegetation); and

• Groundwater movement (if contaminant reached groundwater).


• Ingestion (direct ingestion of soil, groundwater, and fugitive dust); • Dermal contact (dermal/ocular contact with soil during potential future site activity); • Inhalation of volatiles (volatilization of contaminants from near-surface or excavated


8.5.5 Potential Receptors Currently there are no residents or workers on site. Residential use of the site is not anticipated in the future and is not considered. The site is immediately adjacent to an active taxiway and runway and inside a restricted airspace zone.


• Off-site: Groundwater flows northeast, away from the main cantonment. Although people currently reside and work at other locations at Fort Greely, there are no current stationary facilities located down-gradient of the site between the site and Jarvis Creek. However, due to uncertainty in future base development, ingestion, dermal contact, and/or inhalation of volatiles from potentially impacted groundwater, which could potentially be pumped from on-site or offsite wells for residential or worker use, remains a part of this evaluation. Subsistence use of the area and impact to site visitors are not considered realistic scenarios due to site conditions and the site’s proximity to an active taxiway and runway.

8.6 Data Set

8.6.1 Data Sources Table 8-1 presents the data used in the soil screening process, and includes compounds, units, detection frequency, reported concentrations, minimum and maximum reported concentrations, detection limits, and background concentrations for compounds.

The site area of the bermed former fire training area is roughly 50 feet by 120 feet, or approximately 6,000 ft2 (0.13 acre). Most samples used in the soil screening evaluation data set were from inside this area. Several samples were collected during the 1991-1992 investigation from outside this area, and at GFTP-4D East. Note the soil from GFTP-4D East was moved from its original location into the bermed landfarm area at GFTP-4D West (Site 133).

Insitu landfarming was conducted to treat near-surface (upper four to five feet) impacted soils in the former fire training area. Because a remediation program was conducted at the site, pre-


remediation data for POL analytes (GRO, DRO, RRO, PAH) were not included in the data set; however, BTEX compounds were included. The POL analyte data set consists of:

• 1996 and 1997 analytical results from AGRA work involving monitoring of near-surface landfarmed soil in the former fire training pit area; and

• 1998 analytical results from JEG BRAC activity.

For pesticides, PCBs, dioxins/furans, and metals, all available data were included in the data set, including the 1991-1992 data. These compounds may be less affected by biodegradation as a result of the site remediation activity than the POL compounds. Additionally, utilization of pre-remediation results increases the size of the data set, and adds conservatism in the evaluation by capturing elevated concentrations reported prior to the remediation program.

8.6.2 Review of Data Set Detection Limits To complete the valid data set for this site, the detection limits were compared to ADEC Method Two levels. The detection limits were compared to other ADEC or EPA criteria when Method Two levels didn’t exist. In most cases the detection limits reported by the laboratories were less than any ADEC or EPA reporting criteria. There were select cases were this was not true. The exceptions are discussed below.


Benzene: The evaluation of BTEX data included all (1992 through 1998) pre and post remediation data. The data evaluation concentrated on the benzene analysis. The ADEC Method Two level for benzene for migration to groundwater is 0.02 mg/kg. All benzene analysis of the 1998 data yielded non-detects (11 samples) but the detection limit was 0.05 mg/kg. The data set from the 1995-1996 sampling results included 24 non-detects with a detection limit below 0.012 mg/kg. The data set from 1995 included two non-detects and 1992 has 32 non-detects all with detection limits well below ADEC criteria of 0.02 mg/kg. Therefore we can conclude that the samples with results of non-detects are valid and benzene is not a COC.

Methylene Chloride: The detection limit from analysis in the1998 data set was 0.1 mg/kg. The ADEC Method Two level is 0.015 mg/kg. However, this analyte was detected four times at various concentrations (0.04 mg/kg to 0.2 mg/kg). Because the compound was detected at greater than one-half the detection limit, the highest detected concentration is used in the evaluations.

Tetrachloroethylene (PCE): The minimum ADEC Method Two level is 0.03 mg/kg. The 1998 data set included 11 non-detections but the detection limit was 0.05 mg/kg. Analysis of Site 85 South samples resulted in the same detection limits for PCE but yielded an estimated (J flagged) concentration of 0.03J mg/kg. It would be reasonable to assume if PCE was present at this site above 0.03 mg/kg, it should have been detected. It is then reasonable to conclude that the non-detects are valid and PCE is not present at this site.


Semi-volatile Organic Compounds (SVOCs)

Benzo(g,h,i)perylene: The analysis yielded detection limits that ranged from 0.014 mg/kg to 0.3 mg/kg and one detection limit of 6 mg/kg. This analysis yielded an estimated concentration of 0.1J mg/kg.

Phenanthrene: The analysis yielded detection limits that ranged from 0.27 mg/kg to 0.3 mg/kg and one detection limit of 6 mg/kg. Phenanthrene yielded a maximum detection of 0.3J.

Anthracene, Benzo(a)anthracene, Benzo(k)fluoranthene, Benzo(a)pyrene, Bis(2- ethylhexyl)phthalate, Chrysene, Fluoranthene, Indeno(1,2,3,-cd)pyrene, Pyrene: The detection limit from the 1998 analysis for the listed compounds was 0.3 mg/kg, except one result that yielded a detection limit of 6 mg/kg. All of the detection limits (except for the 6 mg/kg) are lower than action levels for all of these analytes. The non-detections are considered valid.

Pesticides/Insecticides /PCBs

alpha-Hexachlorocyclohexane: The ADEC Method Two level is 0.0026 mg/kg. Analysis in 1991 yielded six non-detections with detection limits ranging from 0.01 mg/kg to 0.0186 mg/kg. The results from the 1998 analysis included eight non-detections with a detection limit of 0.01 mg/kg and one non-detection with detection limit of 1.0. However, this analyte was detected in four samples ranging from 0.01 mg/kg to 0.002 mg/kg. This illustrates that the method was able to establish concentrations, when present, as low as 0.002 mg/kg, which is below the ADEC level.

The one sample with the detection limit of 1.0 mg/kg was due to dilution because of high levels of DDT. However, another sample had similar high levels of DDT and was not diluted and the a-BHC level was at 0.04 mg/kg. Therefore, it seems reasonable to conclude that the non-detections are valid and the highest concentration of this analyte at this location is 0.01 mg/kg.

DDD, DDE, DDT: A review of the non-detections showed that the detection limits were lower than the ADEC Method Two levels for all but one sample. For this sample DDT was detected and the detection limit for DDE and DDD was 33 mg/kg. This is above the action level for DDE (24 mg/kg) and just below the level for DDD (35 mg/kg). The non-detects are considered valid.

Aldrin: Aldrin was not detected at this site in any of the analysis performed (1991, 1995 and 1998). All of the non-detections had detection limits below the ADEC Method Two level of 0.50 mg/kg, with the exception of one result in 1998 , which yielded a detection limit of 1.0 mg/kg.

Detection limits from the 1992 analysis are unavailable but would include some high detection limits as seen in the other pesticides/insecticides results from this site. Sampling in 1996-1997 included 27 samples; all yielded non-detections. Four of the 27 results had detection limits above ADEC level of 0.5 mg/kg. (0.6 mg/kg, 1.2 mg/kg, 1.5 mg/kg, 2.9 mg/kg). These samples had been diluted because of high DDT and DDD concentrations. However, samples with similar high DDT and DDD values that were not diluted as much, yielded non-detections for Aldrin. It is reasonable to conclude that no Aldrin is present at this site, and the non-detections are valid.


Endrin: This analyte was detected three times with a maximum concentration of 0.34 mg/kg. Results from the 1991, 1995, and 1998 all yielded detection limits below the ADEC Method Two level of 0.3 mg/kg with the exception of one sample in 1998, which resulted in a detection limit of 1.0 mg/kg.

Several samples in 1992 yielded detection limits above the ADEC level. However, the highest concentration of endrin (0.34 mg/kg) was found in the sample with the highest concentration of DDT. Therefore, it is reasonable to assume that if endrin was present in other samples with the higher detection limits, it should not have been detected at a level higher than the 0.34 mg/kg. This sample, 92GFTP285SL is a triplicate sample for two other samples with high detection limits (9.25 mg/kg & 18.5 mg/kg).

In the 1996-1997 sampling there were several analyses that resulted in detection limits above the ADEC level. However, there were also results with lower detection limits that yielded similar levels of DDT and DDD and non-detections for endrin. Therefore, the non-detections for endrin are valid, with the highest concentration being 0.34 mg/kg.

Heptachlor Epoxide: The ADEC Method Two level is 0.2 mg/kg. This compound was estimated (0.005 J mg/kg) once out of nearly 100 analyses. Even though the detection limits were often above the ADEC level the results indicate that when the compound is present it is detected. A concentration of 0.005 mg/kg is used in the evaluations.

Dieldrin: Dieldrin was detected once at a low level of 0.002 mg/kg. However, about one-half of the samples had detection limits that were above the ADEC Method Two level of 0.015 mg/kg. The site is adequately characterized with a maximum concentration of 0.002 mg/kg.

PCBs: No PCBs were detected. Analysis in 1991 included six non-detections with detection limits of 0.1 mg/kg - 0.35 mg/kg. Analysis in 1992 included non-detections from nine samples. The detection limits for all of these were from 10 mg/kg to 880 mg/kg. Sampling results in 1998 yielded all non-detections with detection limits of 0.10 mg/kg. Given that PCBs have not been detected at the site and that most of the analyses from the latest sampling have detection limits below 10 mg/kg, it can be concluded that PCBs are not a COC for this site.


8.7.1 Initial Screening Process Table 8-2 lists the ADEC Method Two soil cleanup levels from 18 AAC 75.341 Table B1 and Table B2. For each analyte detected, Table 8-2 shows the frequency that the analyte was detected at a concentration that exceeds an ADEC Method Two cleanup level. Where an ADEC Method Two cleanup level was exceeded, the table indicates the specific exposure pathway associated with those criteria. Those analytes without ADEC cleanup criteria are also noted. The table is summarized below.


• 1,2 dibromoethane (migration to groundwater); • 4,4-DDD (ingestion);


• 4,4-DDT (ingestion, migration to groundwater); • endrin (migration to groundwater); • alpha-Hexachlorocyclohexane (migration to groundwater); • methylene chloride (migration to groundwater); • diesel range organics (DRO) (migration to groundwater); • antimony (migration to groundwater); and • arsenic (migration to groundwater).

Detected parameters without Method Two Cleanup Criteria (Table B-1 or B-2) include:

• 1,2,3 trichlorobenzene; • dioxin (listed in Table B-1, but has no pathway specific cleanup levels); and • lead (listed in Table B-1, but has no pathway specific cleanup levels).

8.7.2 Elimination of Analytes Analytes were eliminated for further consideration for two reasons:

1. either the detected concentration represents natural background levels, therefore it should not be considered a contaminant at this site; or

2. insufficient data are available to properly evaluate the compound.

Arsenic was eliminated because the results indicate that the detected concentrations are background levels. The detected arsenic concentration ranged from 5.5 mg/kg to 22 mg/kg. The results from the background analysis ranged from 4 mg/kg to 40 mg/kg.

The only other analyte that was eliminated from further evaluation was 1,2,3 trichlorobenzene. There are not sufficient data to evaluate this compound. The CASRN is 108-70-3. EPA Region 9 PRGs and EPA Region 3 RCBs are not available for this compound. Furthermore there is no information on the IRIS web-site. According to ADEC (Pingree, 26 Sep 01), Health Canada used a reference dose of 0.0015 mg/kg-d, which would result in a calculated ADEC level of 152 mg/kg for soil ingestion (under 40 inch zone). The maximum detected concentration was 0.02 mg/kg. As a result this compound was eliminated from the evaluations.

8.7.3 Findings of Initial Screening The following findings are noted.

1. One result of 1,2 Dibromoethane exceeded the ADEC Method Two level for migration to groundwater.

2. 4,4-DDD exceeded the ADEC Method Two ingestion level and was found in four of 96 samples.

3. 17 of 96 4,4-DDT results exceeded ADEC Method Two cleanup levels. Ingestion and migration to groundwater levels were exceeded.

4. One of 96 endrin results exceeded the ADEC Method Two migration to groundwater level.


5. Two of 96 alpha-hexachlorocyclohexane results exceeded the ADEC Method Two migration to groundwater level.

6. Four of 11 methylene chloride results exceeded the ADEC Method Two migration to groundwater level.

7. Twenty-two of 32 DRO results exceeded the ADEC Method Two migration to groundwater level.

8. Antimony was detected in one sample above the ADEC Method Two migration to groundwater level.


Alternative soil cleanup levels (ACLs) for an industrial/commercial scenario were developed for applicable pathways using the ADEC Method Three Calculator. These ACLs are shown on Table 8-3 and on ADEC Method Three documentation attached at the end of this section.


1. Two of 32 reported DRO results (5400 mg/kg and 4300 mg/kg) exceeded the calculated migration to groundwater ACL (3300 mg/kg).

2. Two of 11 methylene chloride results (0.1 mg/kg and 0.2 mg/kg) exceeded the calculated migration to groundwater ACL (0.0525) mg/kg.

3. The detected concentration of 1,2 dibromoethane (0.03 mg/kg) exceeded the calculated migration to groundwater ACL (0.00056 mg/kg).


5. Dioxin has no ACL. The cleanup level for dioxin is set by a cased by case basis. The highest detected concentration of dioxin was 2x10-7 mg/kg.

8.9 Cumulative Risk

Analytes that were detected at one-tenth or greater of a Method Two cleanup level (smallest value) were included in the cumulative risk calculations. Analytes that do not have an ADEC Method Two cleanup level were also included. The data set is shown in Table 8-2. GRO, DRO, and RRO are not included in the cumulative risk calculations per ADEC methodology.



Detected methylene chloride concentrations exceeded the ACL for migration to groundwater calculated using the ADEC web-based calculator. Methylene chloride was detected in 4 of 11 samples in the data set. Methylene chloride is a common laboratory contaminant, however it was detected at the site during multiple sampling events, and it is not attributed to laboratory


contamination at this time. Detected DRO concentrations also exceeded the ACL for migration to groundwater calculated using the ADEC web-based calculator.

Leachability modeling was conducted using SESOIL to further evaluate the potential for DRO and methylene chloride migration to groundwater. A memorandum describing the procedures and results is provided at the end of this section. The results of the modeling indicated that the DRO contamination will not impact groundwater, and methylene chloride contamination would not reach groundwater at concentrations that would cause groundwater contamination above the ADEC cleanup level.

Although 1,2 dibromoethane was not directly modeled, the potential impact of this analyte can be evaluated by comparing chemical properties and relative concentrations with other modeled analytes. 1,2 Dibromoethane is less soluble than methylene chloride and has a higher Koc (28 L/kg compared to 11.7 L/kg) than methylene chloride. 1,2 Dibromoethane was detected as a estimated J-flagged value in only one sample at a concentration of 0.03 mg/kg, while methylene chloride was detected at an order of magnitude higher (0.2 mg/kg). As a result, it is reasonably deduced that 1,2 dibromoethane will not adversely impact groundwater at this site.


Figure 8-2 illustrates the complete exposure pathways and the human health conceptual site model resulting from the evaluation.

Onsite

There are no current complete exposure pathways. Under future industrial/commercial land use, the following exposure pathways are considered complete:

• ingestion of soil and by workers; and • dermal contact with soil by workers.

Inhalation of volatile organic compounds associated with near-surface impacted soil is considered incomplete because near-surface soil at this site has undergone landfarming.



Offsite

The area down-gradient is not currently occupied by residents or workers. The ADEC Method Three calculator and leachability modeling showed that the soil contamination would not impact groundwater at the site. Under industrial/commercial land use there are no complete off-site pathways.

8.12 Recommendations – Site 133

The following recommendations are based on the results of the evaluation described above.


1. Implementation of institutional controls for industrial/commercial land use is recommended. Controls should include provisions to prevent moving contaminated soil offsite. Additionally, controls should include provisions to prevent drilling a water production well through the contaminated soil.

2. No further active remedial action is recommended for Site 133.

SS01

SS01

SS02

SS06

SS10

SS08

SS04SS05

SS03

SS09

SS11

SIXTH AVENUE

SITE 133

AP−533

Site: Site 133 Date: 16 August 2000 Description: Looking east at Site 133. Berm surrounding site is in foreground.

Berm

Site 133

Photo8-1

SITE 133 PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

11 OCTOBER 2000

REVISIONS:

Active Taxiway

TABLE 8-1DATA SET SITE 133, FORT GREELY, ALASKA




Concentration

Reporting Limits (varies by sample)

*2Background

ConcentrationPETROLEUM HYDROCARBONS (FUELS)

Gasoline Range Organics (GRO) mg/kg 12 / 32 Not Detected (ND), ND, 1.1, ND, ND, 5.1J, ND, ND, ND, ND, ND, ND, 6.3J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

1J 180 0.35 - 5

Diesel Range Organics (DRO) mg/kg 32 / 32 5400, 1200, 1500, 1600, 2900, 1100, 1500, 1200, 130, 180, 59, 94, 44, 75, 260, 320, 270, 670, 620, 180, 280, 281, 420, 440, 990, 4300, 270, 270, 280, 136, 16J, 34

16J 5400 <68 *3

Residual Range Organics (RRO) mg/kg 11 / 11 500, 850, 1200, 1200, 8600, 950, 1000, 680, 290, 70J, 100

70J 8600

VOLATILESBenzene mg/kg 0 / 32 [1998] 11 @ ND(0.05); [1995-96] 24 @ ND(0.0023-

0.012), 3 ND(0.023-0.024); [1995] 2 ND (0.0021); [1992] 32 ND(0.0025-0.005), 0.0069(Background sample)

See detection limits in

"Reported Concentrations"

columnToluene mg/kg 6 / 32 26 @ ND,0.022, 0.042, 0.024, 0.08, 0.07, 0.02 0.02 0.08 0.023 - 0.05 ND - 0.08 *3

Ethylbenzene mg/kg 0 / 32 32 @ ND 0.015 - 0.1Xylenes (total) mg/kg 2 / 32 30 @ ND, 0.06, 0.05 0.05 0.06 0.05 - 0.11,2-Dibromoethane mg/kg 1 / 11 0.03J, 10 @ ND 0.03 0.03 0.05Methylene chloride mg/kg 4 / 11 0.1, 0.04, 0.2, 0.05, 7 @ ND 0.04 0.2 0.11,2,4-Trimethylbenzene mg/kg 1 / 11 10 @ ND, 0.02J 0.02 J 0.02 J 0.21,2,3 trichlorobenzene mg/kg 1 / 11 10 @ ND, 0.02J 0.02 J 0.02 J 0.2

Table 1s R1.xls, 133 Page 1 of 6





Concentration


*2Background

ConcentrationSEMIVOLATILESAcenaphthylene mg/kg 1 / 23 0.064, 21 @ ND, 1 ND(6){DF,DG} 0.064 0.064 0.028 - 0.30, 1 at

6Anthracene mg/kg 2 / 23 0.050, 0.07J, 20 @ ND, 1 ND(6){DF,DG} 0.05 0.07 J 0.036 - 0.3, 1 at 6

Benzo(a)anthracene mg/kg 1 / 23 0.1J, 21 @ ND, 1 ND(6){DF,DG} 0.1 J 0.1 J 0.031 - 0.3, 1 at 6

Benzo(k)fluoranthene mg/kg 1 / 23 0.1J, 21 @ ND, 1 ND(6){DF,DG} 0.1 J 0.1 J 0.026 - 0.3, 1 at 6

Benzo(a)pyrene mg/kg 1 / 23 0.1J, 21 @ ND, 1 ND(6){DF,DG} 0.1 J 0.1 J 0.011 - 0.3, 1 at 6

Benzo(g,h,i)perylene mg/kg 3 / 23 0.037, 0.04J, 0.1J, 19 @ ND, 1 ND(6){DF,DG} 0.037 J 0.1 J 0.014 - 03, 1 at 6

Bis(2-ethylhexyl)phthalate (DEHP)

mg/kg 1 / 11 1.3, 9 @ ND, 1 ND(6){DF,DG} 1.3 1.3 0.3, 1 at 6

Chrysene mg/kg 1 / 23 0.1J, 21 @ ND, 1 ND(6){DF,DG} 0.1 J 0.1 J 0.030 - 0.3, 1 at 6

Fluoranthene mg/kg 1 / 23 0.3J, 21 @ ND, 1 ND(6){DF,DG} 0.3 0.3 0.027 - 0.3, 1 at 6

Indeno(1,2,3,-cd)pyrene mg/kg 2 / 23 0.9J, 0.07J, 20 @ ND, 1 ND(6){DF,DG} 0.07 J 0.9 J 0.011 - 0.3, 1 at 6

Phenanthrene mg/kg 3 / 23 0.11, 0.048, 0.3J, 19 @ ND, 1 ND(6){DF,DG} 0.048 0.3 J 0.043 - 0.3, 1 at 6

Pyrene mg/kg 7 / 23 0.52, 0.12, 0.076, 0.097, 0.32, 0.07J, 0.3J, 15 @ ND, 1 ND(6){DF,DG}

0.07 J 0.52 0.031 - 0.3, 1 at 6






Concentration


*2Background

ConcentrationPESTICIDES / INSECTICIDESBHC (a) (6) (HCH alpha) mg/kg 4 / 96 [1991] 6 @ ND(0.01 - 0.0186); [1992] 48 @ ND,

[1995] ND, ND, [1996-1997] 27 @ ND, [1998] 0.002, 0.004, 0.010, 0.002, 8 @ ND(0.01), 1ND(1.0)

0.002 0.01 0.01 - 1

Chlordane mg/kg 1 / 96 [1991] ND, ND, ND, ND, ND, ND, [1992] 48 @ ND, [1995] ND, ND, [1996-1997] 27 @ ND, [1998] 0.002J, 12 @ ND

0.002 J 0.002 J 0.01 - 1

4,4-DDD mg/kg 47 / 96 [1991] 0.039, 0.0134, ND, ND, 0.33, ND, [1992] 0.013, 4.8, 0.0073, 0.067, 0.860, 41, 42 @ ND, [1995] ND, ND, [1996-1997] 0.38, ND, 32, 24, 26, 16, 46, 30, 45, 0.23, 0.35, 8, 0.89, 0.72, 0.40, 2.3, 0.42, 4.3, 15, 41, 0.47, 1.8, 0.45, 5.1, 4.3, 1.5, 0.78, [1998] 4.9, 1.5, 14, 19, 22, 9.3, 8, 12, 0.73, 0.20, 2.5, ND, 0.87

0.0073 46 0.01 - 20.5, 1 at 33

4,4-DDE mg/kg 44 / 96 [1991] ND, ND, ND, ND, 0.0552, ND, [1992] 0.0098, 2.8, 0.037, 0.094, 44 @ ND, [1995] ND, ND, [1996-1997] 0.076, 0.048, 1.6, 1.1, 1.9, 0.47, 3.1, 1.8, 2.7, 0.082, 0.110, 0.65, 0.26, 0.27, 0.11, 0.25, 0.17, 0.76, 0.35, 1, 0.38, 0.15, 0.14, 0.85, 0.27, 0.48, 0.072, [1998] 0.19, 0.17, 0.78, 0.51, 0.39, 0.07, 0.071, 0.38, 0.047, 0.036, 0.54, ND, 0.106

0.036 3.1 0.01- 20.5, 1 at 33

4,4-DDT mg/kg 84 / 96 [1991] 0.14, 0.0578, ND, ND, 1.2, ND, [1992] 0.66, 0.27, 0.082, 0.0057, 0.36, 0.0091, 2.7, 0.11, 0.011, 0.017, 0.062, 0.12, 0.0029, 0.064, 0.0076, 0.64, 18, 33, 34, 19, 0.41, 0.013, 0.0047, 2.8, 3.2, 0.17, 1.7, 0.006, 0.0088, 0.034, 0.074, 52, 2.1, 55, 9.3, 63, 7.9, 0.0061, 0.011, 9 @ ND, [1995] 0.022, 0.024, [1996-1997] 0.84, 0.61, 110, 68, 110, 26, 150, 91, 160, 0.78, 0.74, 39, 3.7, 6.1, 0.93, 0.81, 4.6, 23, 38, 39, 2.6, 4.6, 2.5, 6.6, 11, 7.6, 3, [1998] 13, 1.9, 51, 42, 19, 11, 12, 13, 2.9, 1.3, 23, 0.009, 8.2

0.0057 160 0.01 -0.022






Concentration


*2Background

ConcentrationEndrin mg/kg 3 / 96 [1991] 1 ND(0.01), 5 ND(0.0325-0.0372); [1992]

0.340J, 0.018J, 23 @ ND(0.0030-0.165), 3 ND(0.31-0.36), 2 ND(0.72-0.74), 2 ND(1.8), 3 ND(8.5 - 18.5); [1995] 2 ND(0.017)?; [1996-1997] 20 @ ND(0.0023-0.28), 3 ND(0.41-0.58), 4 ND(1.2-5.8); [1998] 0.015J, 11 @ ND(0.01), 1 ND(1.0)



column

Heptachlor Epoxide mg/kg 1 / 96 [1991] 6 ND(0.010-0.0186); [1992] 48 @ ND, [1995] 2 ND(0.280), [1996-1997] 20 @ ND(0.011-0.150), 3 ND(0.21-0.28), 4 ND(0.6-2.9); [1998] 0.005J, 11 @ ND(0.01), 1 ND(1.0)



columnDieldrin mg/kg 1 / 96 [1991] 1 ND(0.010), 5 ND(0.0325-0.0372); [1992]

16 @ ND(0.003-0.0078), 7 ND(0.016-0.085), 8 ND(0.155-0.74), 2 ND(1.8), 2 ND(8.5-9.25), 2 ND(17.5-18.5){all subsurface}, 4 ND(0.0031-0.0042), 2 ND(3.4-6.8), 2 ND(20.5-33){all surface samples}; [1995] 2 ND(0.0032); [1996-1997] 7 @ ND(0.0023-0.010), 4 ND(0.021-0.040), 11 ND(0.11-0.58), 4 ND(1.2-5.8); [1998] 0.002J, 11 @ ND(0.01), 1 ND(1.0)



column

POLYCHLORINATED BIPHENYLSTotal PCBs mg/kg 0 / 64 [1991] 9 @ ND(0.1-0.35), [1992] 44 @ ND(10.6 -

880), [1998] 11 @ ND(0.10)ND See detection

limits in "Reported


DIOXINS/FURANS2,3,7,8 TCDD Equivalent (TEF or TEQ)

mg/kg 1 / 15 [1991] 2 @ ND, [1992] 13 @ ND, 2x10-7 2x10-7 2x10-7






Concentration


*2Background

ConcentrationMETALSRCRA metalsArsenic mg/kg 15 / 15 [1991] 5.5-11 [1998] 15-22 5.5 22 4 - 40 *3

Barium mg/kg 15 / 15 [1991] 59.4-102 [1998] 92-168 59.4 168 43 - 651 *3

Cadmium mg/kg 0 / 15 [1991] ND [1998] ND ND ND ND [0.10 - 0.13] *3

Chromium (7) mg/kg 11 / 15 [1991] 7.6-11.1 [1998] 19-25 7.6 25 8 - 43 *3

Lead mg/kg 40 / 40 [1991] 5.2-20 [1992] 4.1-330 [1998] 11-131 4 330 5 - 69 *3

Mercury mg/kg 0 / 15 [1991] ND [1998] ND ND NDSelenium mg/kg 0 / 15 [1991] ND [1998] ND ND ND 0.3J - ND[1] *3

Silver mg/kg 0 / 15 [1991] ND [1998] ND ND NDOther metals Aluminum mg/kg 15 / 15 [1991] 4880-8843 [1998] 10600-15000 4,880 15,000 65,000 *4

Antimony mg/kg 12 / 15 [1991] ND-13.6 [1998] 0.5-0.96 0.5J 0.96J 0.66 *5

Beryllium mg/kg 11 / 15 [1991] ND [1998] 0.2-0.4 0.2J 0.4J 1.35 *4

Calcium mg/kg 15 / 15 [1991] 1510-4290 [1998] 1420-2690 1,420 4,290 20,000 *4

Cobalt mg/kg 15 / 15 [1991] 5.0-8.3 [1998] 10-12 5 12 14 *4

Copper mg/kg 15 / 15 [1991] 19.5-20.8 [1998] 22-27 20 27 29 *4

Iron mg/kg 15 / 15 [1991] 10200-17100 [1998] 20800-27700 10,200 27,700 38000 *4

Magnesium mg/kg 15 / 15 [1991] 2870-3300 [1998] 3640-4580 2,870 4,580 12000 *4

Manganese mg/kg 15 / 15 [1991] 231-332 [1998] 248-419 231 419 670 *4

Nickel mg/kg 4 / 15 [1991] 12.4-18.6 [1998] ND 12.4 18.6 33 *4

Potassium mg/kg 15 / 15 [1991] 708-1180 [1998] 664-877 664 1,180 13000 *4

Sodium mg/kg 15 / 15 [1991] 192-378 [1998] 88-137 88 378 15000 *4

Thallium mg/kg 0 / 15 [1991] ND [1998] ND ND ND 0.25 *6

Vanadium mg/kg 15 / 15 [1991] 16.8-24.4 [1998] 29-39 16.8 39 129 *4

Zinc mg/kg 15 / 15 [1991] 25.5-31.8 [1998] 42-71 25.5 71 79 *4






Concentration


*2Background

ConcentrationNOTES:Footnote *1 = Not all nondect (ND) parameters are shown in table.Footnote *2 = See Data sets in Appendices.Footnote *3 = Jacobs Engineering Group (August 2000) Summary Report 1999 Remedial Investigation / Removal Acton, Fort Greely, Alaska.Footnote *4 = United States Geological Survey (USGS) Professional Paper 1458, “Element Concentrations in Soils and Other Surficial materials of Alaska,” 1988.



B = analyte found in associated blank as well as in sample.

J = value is estimated and below quantitation limit.

U = compound was analyzed for, but not detected.



SITE 133, FORT GREELY, ALASKA


Concentration







CalculationsPETROLEUM HYDROCARBONS (FUELS)Gasoline Range Organics (GRO) mg/kg 180 0 / 32 1,400 1,400 300



VOLATILES

Toluene mg/kg 0.08 0 / 32 20,300 180 5.4

Xylenes (total) mg/kg 0.06 0 / 32 203,000 81 78

1,2-Dibromoethane mg/kg 0.03 1 / 11 0.1 1.3 0.0002 Migration to Groundwater

Methylene chloride mg/kg 0.2 4 / 11 1,100 180 0.015 Migration to Groundwater

1,2,4-Trimethylbenzene mg/kg 0.02 J 0 / 11 5070 92.2 95.2

1,2,3 Trichlorobenzene mg/kg 0.02 J n / a No ADEC limit Not used see text

SEMIVOLATILES

Acenaphthylene mg/kg 0.064 0 / 23 6,100 210

Anthracene mg/kg 0.07 J 0 / 23 30,000 4300

Benzo(a)anthracene mg/kg 0.1 J 0 / 23 11 6

Benzo(k)fluoranthene mg/kg 0.1 J 0 / 23 110 200

Benzo(a)pyrene mg/kg 0.1 J 0 / 23 1 3

Benzo(g,h,i)perylene mg/kg 0.1 J 0 / 23 3000 1500


Chrysene mg/kg 0.1 0 / 23 1,100 620





Concentration







CalculationsFluoranthene mg/kg 0.3 0 / 23 4,100 2100

Indeno(1,2,3,-cd)pyrene mg/kg 0.9 J 0 / 23 11 54

Phenanthrene mg/kg 0.3 J 0 / 23 30000 4300

Pyrene mg/kg 0.52 0 / 23 3,000 1500

PESTICIDES/INSECTICIDES

BHC (a) (6) (HCH alpha) mg/kg 0.01 2 / 96 1.3 5.5 0.0026 Migration to Groundwater

Chlordane mg/kg 0.002 J 0 / 96 6 140 3

4,4-DDD mg/kg 46 4 / 96 35 47 Ingestion

4,4-DDE mg/kg 3.1 0 / 96 24 150 exceeded 1/10 of ingestion

4,4-DDT mg/kg 160 17 / 96 24 5,300 88 Ingestion, Migration to Groundwater

Endrin mg/kg 0.34 J 1 / 96 30 0.3 Migration to Groundwater

Heptachlor Epoxide mg/kg 0.005 0 / 96 0.9 33 0.2

Dieldrin mg/kg 0.002 J 0 / 96 0.5 8 0.015

DIOXINS/FURANS

2,3,7,8 TCDD Equivalent (TEF or TEQ) mg/kg 2x10-7 n / a - No ADEC limit

METALS

RCRA metals

Lead mg/kg 330 n / a 400 - No ADEC limit

Other metals

Antimony mg/kg 13.6 1 / 15 41 3.6 Migration to Groundwater

J = estimated value





Concentration

Frequency Detected Above ADEC Method 3 Alternative

Cleanup Level (ACL)


(industrial)


(industrial)



ExceededPETROLEUM HYDROCARBONS (FUELS)Diesel Range Organics (DRO) mg/kg 5400 2 / 32 12,500 12,500 3,300 Migration to

Groundwater

VOLATILES1,2-Dibromoethane mg/kg 0.03 1 / 11 0.672 0.998 0.00056 Migration to

GroundwaterMethylene chloride mg/kg 0.2 2 / 11 7,610 132 0.0525 Migration to

Groundwater

SEMIVOLATILES

PESTICIDES/INSECTICIDESBHC (a) (6) (HCH alpha) mg/kg 0.01 0 / 96 9.06 6.08 0.02234,4-DDD mg/kg 46 0 / 96 238 6364,4-DDT mg/kg 160 0 / 96 168 6,000 1160Endrin mg/kg 0.34 J 0 / 96 613 4.36

DIOXINS/FURANS2,3,7,8 TCDD Equivalent (TEF or TEQ) mg/kg 2x10-7 n/a

METALSRCRA metalsLead mg/kg 330 1 / 15Other metals Antimony mg/kg 13.6 0 / 15 818 31.6

J = estimated value

To be determined



STEP 4:


These cleanup levels should be printed. To print, please select the print function on your web browser. This page may also be saved and emailed for documentation of the calculated cleanup levels. For best results, save the page as a "Web Archive for email" file (.mht) if your browser supports this; in Internet Explorer 5 choose "Save as..." from the file menu and change the "Save

Chemical Name Chemical Type Ingestion InhalationMigration

to GW

1,2 Dibromoethane

Organic 0.672 0.998 0.00056


Methylene chloride

Organic 7610 132 0.0525

Lead Inorganic

HCH, a- Organic 9.06 6.08 0.0223


Endrin Organic 613 4.36


Dioxin Organic

DDT Organic 168 6000 1160

DDE Organic 168 1980

DDD Organic 238 636

Antimony Inorganic 818 31.8

Chemical Notes

DioxinDioxin cleanup levels must be determined on a site-specific basis.





as type" to "Web Archive for email". Other browsers should have a similar choice.






















Continue

STEP 5:




Total risks exceed the benchmark values of a hazard index of 1 and/or a cancer risk of 0.00001. Cleanup levels must be lowered to meet these cumulative risk benchmarks.



Chemical Name Concentration (mg/kg) Cancer Risk Hazard

Quotient

1,2 Dibromoethane 0.03 7.5e-7 0.021

Antimony 13.6 0 0.017

DDD 46 0.0000019 0

DDE 3.1 1.9e-7 0

DDT 160 0.0000098 0.16

Dioxin 7e-7 0 0

Endrin 0.34 0 0.00055

HCH, a- 0.01 2.8e-8 0

Lead 330 0 0

Methylene chloride 0.2 1.5e-8 0.000032


9.0 SITE 112

9.1 Site Location and Background – Site 112

Site 112 was formerly a fenced salvage area reportedly with unknown storage practices (EBS, Woodward-Clyde 1996). Site 112 is located near the southwest terminus of Magnolia Road and encompasses approximately 1.2 acres (Figure 1-1). Photo 9-1 shows Site 112 on 16 August 2000.

Site investigation activities were conducted at Site 112 in 1998. Figure 9-1 shows locations of borings, test pits, and sampling conducted at the site.

Fort Greely information was recently identified that suggests the site may have been used for storage of munitions.

9.2 Identified Documentation and Past Site Activity– Site 112

The following identified documents provide information about Site 112. Selected items of supporting documentation are included in Appendix 112.

1. SAIC (January 1990) RCRA Facility Assessment PR/VSI Report. Based on similarities in descriptions, Site 112 might have actually been SWMU No. 40, with the location of SWMU No. 40 shown incorrectly in this document.


3. April 1999, Jacobs Engineering Group Inc. 1998 Remedial Investigation Report, Fort Greely, Alaska, Final. Section 26.0 of the report presents the methodology and results of investigation activities conducted at the site under the 1998 BRAC EI/LRI field program.

4. August 2000, Radian International / Jacobs Engineering Group Inc. Summary Report, 1999 Remedial Investigation/Removal Action, Fort Greely, Alaska, Final. Section 3.5.6 and Section 7.15 of the report summarize the affect of additional background investigation on COPCs for the site.

9.2.1 Pre-BRAC Investigation Activities Investigation work was not conducted at Site 112 prior to BRAC activity.


9.2.3 1998 Investigation Activities JEG conducted the following investigation activities in 1998.

• UXO clearance observation was conducted prior to investigation activities. Although scrap metal items and items related to munitions were found, no UXO was identified.


• A geophysical survey was conducted over the northern area of the site using electro-magnetic techniques.

• Nine test pits were excavated and sampled, ranging in depth from four to ten feet bgs (TP-928 through TP-936).

• Four soil borings were drilled and sampled (AP-937 through AP-940) ranging in depth from 11.5 to 35 feet bgs.

• Thirteen surface soil samples were collected. • Selected soil samples were analyzed for DRO, RRO, GRO, VOC, SVOC, pesticides,

PCBs, and metals.

9.2.4 1999 Investigation Activities Activities were not conducted at the site during 1999 BRAC efforts. However, additional background sampling at Fort Greely did affect the COPCs for the site.

9.3 Potential Contaminants – Site 112

According to the 1998 Remedial Investigation Report (Jacobs, 1999), the investigation at Site 112 was conducted to evaluate the potential environmental impact resulting from the potential storage of diesel fuel, solvents, and pesticides in the former fenced salvage area. Project samples were analyzed for VOCs, SVOCs, GRO, DRO, RRO, OCPs, PCBs, and metals.

9.4 Synopsis of Contaminant Distribution – Site 112

Results of the 1998 investigation activity indicate POL, pesticides, and metals impact Site 112. Detections of methylene chloride and trichloroethylene are noted.

Based on additional background sampling and evaluation of metals concentrations as part of the 1999 BRAC work, it was determined that there is no evidence of metals concentrations above background levels in the deeper soil horizon at Site 112. However, the background analysis indicated that there is evidence of mercury and lead impact above background levels in shallow soils at Site 112 (0 to 2 feet bgs) (Jacobs, August 2000). Note that detected concentrations of mercury and lead did not exceed regulatory criteria.

The 1998 BRAC report indicated that pesticide contamination was located in discrete regions across the site. These localized areas appeared to extend to a maximum depth of about six feet bgs. Review of sampling results also indicates that the impact of POL and trichloroethylene are limited to the upper 6 feet. Methylene chloride was reported at concentrations above the ADEC Method Two migration to groundwater criteria down to 16.5 feet bgs.

Scrap metal was encountered at the surface and in subsurface soil. Items included expended smoke grenades, slap flares, 5.56 mm blanks, 155-mm illumination projectile, 2.75-inch rocket fin, and a 0.50-caliber link. No UXO was observed during the work.

9.5 Preliminary (Pre-Evaluation) Human Health Conceptual Site Model – Site 112

A pre-evaluation human health conceptual site model is described below. This description reflects conditions and pathways prior to conducting the ADEC Method Three evaluation. The


results of the ADEC Method Three evaluation modify the conceptual site model to that described in Section 9.11.

9.5.1 Contamination Source(s) The contamination source is impacted soil as well as scrap metal items. Surface water does not exist on site. Groundwater is estimated to be greater than 170 feet below the ground surface at the site.


• Petroleum (GRO, DRO, RRO); • Volatile organic compounds; • Semivolatile organic compounds; • Pesticides; and • Metals.

Based on background sampling conducted under the BRAC program, metals concentrations in soils deeper than 2 feet bgs are attributed to background levels. Shallow soils appear to be impacted by lead and mercury, however concentrations did not exceed regulatory levels.



Soil Transport Via Erosion and Dispersion: [Incomplete]. The impacted area is roughly flat and vegetated. Surrounding area is also vegetated. See Photo 9-1.

Migration to Groundwater and Groundwater Transport: [Potentially complete]. Some analyte concentrations exceed published migration to groundwater criteria. Migration to groundwater and groundwater transport are considered “potentially complete” exposure pathways, unless or until documented by further evaluation to be incomplete.

Runoff to Surface Water or Surface Sediment, Surface Water Transport: [Incomplete]. The nearest surface water feature is Jarvis Creek (approximately 7000 feet to the east). Based on site reconnaissance, drainage channels do not appear to connect the site with Jarvis Creek, and area run-off infiltrates prior to reaching Jarvis Creek.

9.5.3 Migration Pathways

Recognized potential migration pathways consist of:


near the contaminated area at the site); • Excavation (potential future activity); • Fugitive dust via contaminant dispersion (note the contaminated area is currently

vegetated, however future site work could remove or disturb vegetation); and • Groundwater movement (if contaminant reached groundwater).



• Ingestion (direct ingestion of soil, groundwater, and fugitive dust); • Dermal contact (dermal/ocular contact with soil during potential future site activity);

and • Inhalation of volatiles (volatilization of contaminants from near-surface or excavated


9.5.5 Potential Receptors Currently there are no residents or workers on site. Residential use of the site is not anticipated in the future and is not considered. The site is on Fort Greely adjacent to a former landfill.


• Off-site: Groundwater flows northeast, away from the main cantonment. People currently work at North Post adjacent to the airfield. Due to uncertainty in future base development, ingestion, dermal contact, and/or inhalation of volatiles from potentially impacted groundwater, which could potentially be pumped from on-site or offsite wells for residential or worker use, remains a part of this evaluation.

Subsistence use of the site area and impact to site visitors are not considered realistic scenarios due to site conditions.

9.6 Data Set

9.6.1 Data Sources Table 9-1 presents the data used in the soil evaluation process, and includes compounds, units, detection frequency, reported concentrations, minimum and maximum reported concentrations, detection limits, and background concentrations for compounds.

The area of impact where detected contaminants exceed regulatory levels is located in the northern area of the site. Although impacted areas are believed to be small discrete zones within the northern site area, the broad general area containing these zones is estimated at roughly 260 feet by 200 feet, or approximately 52,000 ft2 (1.2 acre).

The data set consists of all analytical results known to exist from the site. These results are presented in the 1998 BRAC report (Jacobs, 1999).

9.6.2 Review of Data Set Detection Limits

To complete the valid data set for this site, the detection limits were compared to ADEC Method Two levels. Where none existed the detection limits were compared to other ADEC or EPA criteria. In most cases, the detection limits reported by the laboratories were less than ADEC or EPA reporting criteria. There were select cases were this was not true. The exceptions are discussed below.



Benzene: The ADEC Method Two level for migration to groundwater is 0.02 mg/kg. All results from the 1998 analysis yielded non-detects (11 samples). However, the detection limits ranged from 0.087 mg/kg to 0.27 mg/kg. A value (0.14 mg/kg), one-half of the highest detection limit, is carried forward in this evaluation.

Methylene Chloride: The ADEC Method Two level is 0.015 mg/kg. The detection limits ranged from 0.087 mg/kg to 0.27 mg/kg. However, this compound was detected in 17 of 23 samples with a maximum reported value of 0.24 mg/kg. Because methylene chloride was detected at greater than one-half the detection limit, the highest reported concentration is used in subsequent calculations.

Trichloroethene (TCE): The ADEC Method Two level for migration to groundwater for TCE is 0.027 mg/kg. The results of the 1998 analysis included 22 non-detects. The detection limits ranged from 0.087 mg/kg to 0.27 mg/kg. TCE was estimated in one sample at 0.039 J mg/kg. This estimated value is used in the evaluations.

Tetrachloroethylene (PCE): PCE was not detected at this site. Detection limits ranged from 0.087 mg/kg to 0.27 mg/kg, which are above the ADEC Method Two level of 0.03 mg/kg. Analysis of Site 85 South samples resulted in the same detection limit range, yet yielded an estimated value of 0.03 mg/kg (J flagged). It could be reasonably assumed that if PCE was present at this site above 0.03 mg/kg it should have been detected and flagged. Therefore, it is reasonable to conclude that the non-detections are valid and PCE is not present at this site.

Semi-Volatile Organic Compounds (SVOCs)

All SVOCs: With the exception of two analytes (2 of 23 samples) the detection limits for the SVOCs analysis ranged from 0.17 mg/kg to 0.20 mg/kg. Most of the SVOCs ADEC Method Two levels are above the reported detection limits and the non-detections are valid.

The lowest ADEC Method Two level for Dibenz (a,h)anthracene and Benzo(a)pyrene is 1 mg/kg. The detection limits were 0.9 mg/kg for one analysis and 1.8 mg/kg for another. Neither of these were detected at this location. The non-detections are considered valid.

Pesticides/Insecticides/PCBs

PCB: No PCBs were detected at Site 112. Detection limits ranged from 1 mg/kg to 1.2 mg/kg for individual PCBs (Aroclor 1016 and 1254 only). Detection limits for total PCBs ranged from 6 mg/kg to 7.2 mg/kg. Given that PCBs have not been detected at this site and that most of the results from the latest analysis have had detection limits below 10 mg/kg we can conclude that PCBs are not a COC for this site. Also, no PCBs were detected at Sites 85 North, 85 South or 133. Results from other sites with detection limits less than 1 mg/kg yielded all non-detects.



9.7.1 Initial Screening Process Table 9-2 lists the ADEC Method Two soil cleanup levels from 18 AAC 75.341 Table B1 and Table B2. For each analyte detected, Table 9-2 shows the frequency that the analyte was detected at a concentration that exceeds an ADEC Method Two cleanup level. Where an ADEC Method Two cleanup level was exceeded, the table indicates the specific exposure pathway associated with those criteria. Those analytes without ADEC cleanup criteria are also noted. The table is summarized below.


• benzene (migration to groundwater); • methylene chloride (migration to groundwater); • trichloroethene (TCE) (migration to groundwater); • alpha-Hexachlorocyclohexane (a-HCH) (migration to groundwater); • 4,4-DDD (ingestion); • 4,4-DDT (ingestion); • diesel range organics (DRO) (migration to groundwater); • arsenic (ingestion ,migration to groundwater); and • chromium (migration to groundwater).

Detected parameters without Method Two Cleanup Criteria (Table B-1 or B-2) include:

• Lead (listed in Table B-1, but has no pathway specific cleanup levels).

9.7.2 Elimination of Analytes Arsenic and chromium were eliminated for further consideration because the detected concentrations represent natural background levels. Therefore, they are not considered contaminants at this site.

The detected arsenic concentration ranged from 4.1 mg/kg to 31 mg/kg. The results from the background analysis ranged from 4 mg/kg to 40 mg/kg. Chromium results ranged from 6 mg/kg to 50.4 mg/kg, whereas the background analysis yielded results that ranged from 8 mg/kg to 43 mg/kg. Note that statistical analysis presented in the 1999 Summary Report (Jacobs, August 2000) indicates detected chromium to be representative of background.

9.7.3 Findings of Initial Screening


1. The value used for benzene, 0.14 mg/kg, (one-half of the highest detection level) exceeds the ADEC Method Two migration to groundwater level.

2. 15 of 23 methylene chloride resultsexceeded the ADEC Method Two migration to groundwater level.


3. One estimated (J-flagged) result out of 23 trichloroethylene results exceeded the ADEC Method Two migration to groundwater level.

4. Two of 30 HCH-a results exceeded the ADEC Method Two migration to groundwater level.

5. One of 30 4,4-DDD results exceeded the ADEC Method Two ingestion level.

6. One of 30 4,4-DDT results exceeded the ADEC Method Two ingestion level.

7. Five of 23 DRO results exceeded the ADEC Method Two migration to groundwater level.


Alternative soil cleanup levels (ACLs) for an industrial/commercial scenario were developed for all applicable pathways using the ADEC Method Three Calculator. These ACLs are shown on Table 9-3 and on ADEC Method Three documentation attached at the end of this section.


1. The benzene value carried forward in this evaluation (0.14 mg/kg based on one-half the highest detection limit) exceeded the migration to groundwater ACL of 0.114 mg/kg.

2. Nine of 23 methylene chloride results (all estimated J flagged, highest 0.24J mg/kg) exceeded the migration to groundwater ACL of 0.0525 mg/kg.


9.9 Cumulative Risk

Analytes that were detected at one-tenth or greater of a Method Two cleanup level (smallest value) were included in the cumulative risk calculations. The data set is shown on Table 9-2. GRO, DRO, and RRO are not included in the cumulative risk calculations per ADEC methodology.



Methylene chloride was detected in 17 of 23 samples in the data set. Nine of the 23 results exceeded the calculated ACL for the migration to groundwater pathway. Methylene chloride is a common laboratory contaminant; however, it has been detected at other Fort Greely sites in other sampling events, and it is not attributed to laboratory contamination at this time.

Leachability modeling was conducted using SESOIL to further evaluate the potential for methylene chloride migration to groundwater. A memorandum describing the procedures and results is at the end of this section. The results of modeling indicated that the methylene chloride


contamination would not reach groundwater at a concentration that would cause groundwater to exceed the ADEC cleanup level.

The benzene value (0.14 mg/kg) exceeded the ACL for the groundwater pathway by 0.026 mg/kg. Because of the small exceedance and that the value that was carried forward was a non-detected value, no action is recommended for this compound. Leachability modeling was conducted for benzene at a different Fort Greely BRAC site (Site 73). Site 73 is the location of a prior large fuel spill. The methodology and results of that modeling are presented in the Limited Risk Evaluation (Hart Crowser/Jacobs, November 2001). Benzene at Site 73 was modeled at 6.1 mg/kg, over an order of magnitude higher than the value carried forward for Site 112. Although breakthrough was predicted, modeled groundwater concentrations did not exceed the ADEC cleanup level.


Figure 9-2 illustrates the complete exposure pathways and the final human health conceptual site model.

Onsite

There are no current complete exposure pathways. Under future industrial/commercial land use, the following exposure pathways are considered complete:

• ingestion of soil by workers; • dermal contact with soil by workers; and • inhalation of volatile organic compounds associated with near-surface impacted soil.



Offsite

The area close to the site down-gradient is not currently occupied by residents or workers. Workers are present farther down-gradient at the airfield. The leachability modeling showed that the soil contamination would not impact groundwater at levels exceeding ADEC cleanup levels. Under industrial/commercial land use there are no complete off-site pathways.

9.12 Recommendations – Site 112

The following recommendations are based on the results of the evaluation described above.

1. Implementation of institutional controls for industrial/commercial land use is recommended. Controls should include provisions to prevent moving contaminated soil offsite. Controls should also include provisions to prevent drilling a water production


well through the contaminated soil. Additionally, controls should specifically note the potential prior storage of munitions at the site.

2. No further active remedial action is recommended for Site 112.

SS1

TP−928

SS1

SS2

SS3

SS4

SS5

SS6

SS7

SS8

SS13SS9SS11

SS12

SS10

TP−932

TP−931

TP−934

TP−933

TP−930

TP−928

TP−929

Site: Site 112 Date: 16 August 2000 Description: Looking west at north end of Site 112 from northeast corner of site near Magnolia Road.

Photo9-1

SITE 112 PHOTOGRAPH FORT GREELY, ALASKA

SCALE: NTS

11 OCTOBER 2000

REVISIONS:

TABLE 9-1DATA SET, SITE 112, FORT GREELY, ALASKA




Concentration



PETROLEUM HYDROCARBONS (FUELS)Gasoline Range Organics (GRO) mg/kg 3 / 23 Not Detected (ND), ND, 1.1, ND, ND, 5.1J, ND,

ND, ND, ND, ND, ND, 6.3J, ND, ND, ND, ND, ND, ND, ND, ND, ND, ND

1.1 6.3 J 3.1 - 10

Diesel Range Organics (DRO) mg/kg 14 / 23 990, 1700, 1200, ND, 200, 79, 33, ND, 13, ND, 420, ND, 15, ND, 150, ND, 210, 100, 1800, 170, ND, ND, ND

13 1800 4.1 - 8.3 <68 *3

Residual Range Organics (RRO) mg/kg 14 / 23 420, 700, 130, ND, 1200, 520, 700, ND, 360, ND, 200, ND, 230, ND, 1600, ND, 9800, 3000, 2700, 2000, ND, ND, ND

130 9800 100 - 210

VOLATILESBenzene mg/kg 0/23 23 ND 0.087 - 0.27Toluene mg/kg 4 / 23 ND, ND, ND, ND, ND, ND, 0.012J, ND, ND,

0.24J, ND, ND, ND, ND, .027J, ND, 0.011J, ND, ND, ND, ND, ND, ND

0.011 J 0.24 J 0.11 - 0.27 ND - 0.08 *3

Ethylbenzene mg/kgXylenes (total) mg/kg 1 / 23 0.072J, 22@ND 0.072 J 0.072 J 0.35 - 0.64Sec-Butylbenzene mg/kgTert-Butylbenzene mg/kgCarbon Tetrachloride mg/kgChlorobenzene mg/kgChloroform mg/kg1,2-Dibromoethane mg/kg1,2-Dichloroethane (EDC) mg/kgcis-1,2-Dichloroethene mg/kgCis-1,2-Dichloroethane mg/kg1,1-Dichloroethylene mg/kgn-Hexane mg/kgIsopropylbenzene (cumene) mg/kg4-Isopropyltoluene (cymene) mg/kg






Concentration



Methylene chloride mg/kg 17 / 23 0.049J, 0.047J, ND, 0.09J, 0.086J, 0.057J, 0.096J, 0.036J, 0.057J, 0.23J, 0.013J, 0.062J, 0.071J, 0.046J, 0.24, ND, ND, ND, ND, ND, 0.029J, 0.025J, 0.013J

0.013 J 0.24 0.18 - 0.27

Methyl ethyl ketone mg/kgMTBE (Tert-butyl methyl ether) mg/kgn-Propylbenzene mg/kg1,1,2,2-Tetrachloroethane mg/kgTetrachloroethylene (PCE) mg/kg1,1,1-Trichloroethane mg/kgTrichloroethene (TCE) mg/kg 1 / 23 0.039J, 22@ND 0.039 J 0.039 J 0.11 - 0.27Trichlorofluoromethane mg/kg1,2,4-Trimethylbenzene mg/kg1,3,5-Trimethylbenzene mg/kgVinyl Chloride mg/kg1,2,3 trichlorobenzene mg/kg

SEMIVOLATILESAcenaphthene mg/kgAcenaphthylene mg/kgAnthracene mg/kgBenzo(a)anthracene mg/kgBenzo(k)fluoranthene mg/kgBenzo(b)fluoranthene mg/kgBenzo(a)pyrene mg/kgBenzo(g,h,i)perylene mg/kgBenzoic Acid mg/kg 18 / 23 ND, 1J, ND, 0.34J, 1.5J, 0.78J, 0.87J, 0.13J, 0.76J,

0.6J, 0.54J, 0.55J, 0.85J, 0.73J, 0.81J, 200J, 1.8J, 0.66J, 2.7J, 1.4J, ND, ND, ND

0.13 J 200 J 0.17- 0.2, [email protected], 1@ 1.8

Benzyl Alcohol mg/kgBis(2-ethylhexyl)phthalate (DEHP) mg/kg 2 / 23 0.065J, 0.22, 21@ND 0.065 J 0.22 0.17- 0.2,

[email protected], 1@ 1.8

Butylbenzylphthalate mg/kg






Concentration



Carbazole mg/kgChrysene mg/kg 3 / 23 0.73J, 0.13J, 0.042J, 20@ND 0.042 J 0.73 J 0.17, 0.18Cresol (total) mg/kgDibenzofuran mg/kgDibenz(a,h)anthracene mg/kg1,4-Dichlorobenzene mg/kgDimethylphthalate mg/kg2,4-Dinitrotoluene mg/kgFluoranthene mg/kg 1 / 23 0.025J, 22@ND 0.025 J 0.025 J 0.17- 0.2,


Fluorene mg/kg 1 / 23 0.013J, 22@ND 0.013 J 0.013 J 0.17- 0.2, [email protected], 1@ 1.8

Hexachlorobenzene mg/kgHexachloro-1,3-butadiene mg/kgHexachloroethane mg/kgIndeno(1,2,3,-cd)pyrene mg/kgIsophorone mg/kg2-Methylnaphthalene mg/kg 2 / 23 0.12J, 0.15J, 21@ND 0.12 J 0.15 J 0.17- 0.2,


Naphthalene mg/kg 2 / 23 0.036J, 0.074J, 21@ND 0.036 J 0.074 J 0.17- 0.2, [email protected], 1@ 1.8

Nitrobenzene mg/kg4-Nitrophenol mg/kgPentachlorophenol mg/kgPhenanthrene mg/kg 3 / 23 ND, 0.089J, ND, ND, ND, ND, 0.085J, ND, ND,

ND, ND, ND, ND, ND, 0.088J, ND, ND, ND, ND, ND, ND, ND, ND

0.085 J 0.089 J 0.17- 0.2, [email protected], 1@ 1.8

Di-n-butyl phthalate mg/kg






Concentration



Pyrene mg/kg 5 / 23 ND, ND, ND, ND, 0.022J, 0.025J, 0.014J, ND, ND, ND, ND, ND, ND, ND, 0.023J, ND, 0.39J, ND, ND, ND, ND, ND, ND

0.014 J 0.39 J 0.17- 0.2, [email protected]

Pyridine mg/kg2,4,5 Trichlorophenol mg/kg2,4,6 Trichlorophenol mg/kg

PESTICIDES / INSECTICIDES

Aldrin mg/kgBHC (a) (6) (HCH alpha) mg/kg 5 / 30 0.0046, 0.0026, 0.0005J, 0.0035, 0.0021, 25@ND 0.0005 J 0.0046 0.0007, 0.0017

BHC (b) (6) (HCH beta) mg/kg 2 / 30 0.0053, 0.0024J, 28@ND 0.0024 J 0.0053 0.0007, 0.0017

BHC (g) Lindane (6) (HCH gamma) mg/kg 2 / 30 0.0003J, 0.002J, 28@ND 0.0003 J 0.002 J 0.0007

Chlordane mg/kg2,4-D (2,4-Dichlorophenoxyacetic acid) mg/kg

4,4-DDD mg/kg 16 / 30 ND, ND, 0.0052, ND, 36, 3.6, 0.0038, ND, 0.0023, ND, ND, ND, 0.015, 0.004J, 0.034, ND, 0.19, 0.051, 0.12, 0.12, 0.0013, ND, ND, 0.025, ND, ND, ND, ND, 0.025, 0.003J

0.0013 36 0.0007 - 0.010

4,4-DDE mg/kg 20 / 30 ND, ND, ND, 0.0002J, 3.1, 0.52, 0.003, ND, 0.001, 0.0002, ND, ND, 0.037, 0.0003J, 0.0058, ND, 4.7, 0.1, 0.27, 0.076, 0.0002J, 0.0001J, ND, 0.010J, 0.002J, 0.002J, ND, ND, 0.035, 0.003J

0.0001 J 4.7 0.0007 - 0.010

4,4-DDT mg/kg 22 / 30 0.013, ND, 0.017, 0.0007, 87, 11, 0.02, ND, 0.0082, ND, 0.048, ND, 0.068, 0.0025, 0.2, ND, 0.13, 0.1, 0.39, 0.42, 0.006, ND, ND, 0.31, 0.015, 0.014, 0.014, ND, 0.84, 0.1

0.0007 87 0.0007 - 0.010

Endosulfan mg/kg 9 / 60 0.0031, 0.0055, 0.0029, 0.0008, 0.012, 0.026, 0.06, 0.0016, 0.0081, 51@ND

0.0016 0.06 0.0007






Concentration



Endrin mg/kgHeptachlor mg/kgHeptachlor Epoxide mg/kgMethoxychlor mg/kgToxaphene mg/kgDieldrin mg/kg2,4,5-TP (2-(2,4,5-trichlorophenoxy)propionic acid)

mg/kg

POLYCHLORINATED BIPHENYLSAroclor 1016 mg/kgAroclor 1254 mg/kgTotal PCBs mg/kg 0 / 23 23 @ ND 1 - 1.2(single

PCB), 6 - 7.2 (total PCB)

DIOXINS/FURANS2,3,7,8 TCDD Equivalent (TEF or TEQ)

mg/kg

METALSRCRA metals

Arsenic mg/kg 33 / 33 4.1 31 4 - 40 *3

Barium mg/kg 23 / 23 41.8 222 43 - 651 *3

Cadmium mg/kg ND [0.10 - 0.13] *3

Chromium (7) mg/kg 33 / 33 6.1 50.4 8 - 43 *3

Lead mg/kg 19 / 23 5.2 210 5 - 69 *3

Mercury mg/kg 9 / 23 0.035 0.086Selenium mg/kg 17 / 23 0.24 0.57 0.3J - ND[1] *3

Silver mg/kg






Concentration



Other metals Aluminum mg/kg 23 / 23 3,000 21,400 65,000 *4

Antimony mg/kg 23 / 23 0.35 2.7 0.66 *5

Beryllium mg/kg 23 / 23 0.024 0.219 1.35 *4

Calcium mg/kg 23 / 23 1,100 5,990 20,000 *4

Cobalt mg/kg 23 / 23 1.53 18.1 14 *4

Copper mg/kg 23 / 23 14 106 29 *4

Iron mg/kg 23 / 23 6,800 32,700 38000 *4

Magnesium mg/kg 23 / 23 1,800 6,840 12000 *4

Manganese mg/kg 23 / 23 180 524 670 *4

Nickel mg/kg 23 / 23 8.9 38 33 *4

Potassium mg/kg 23 / 23 611 2,290 13000 *4

Sodium mg/kg 23 / 23 59 293 15000 *4

Thallium mg/kg 0.25 *6

Vanadium mg/kg 23 / 23 12 53.5 129 *4

Zinc mg/kg 23 / 23 17 96 79 *4

NOTES:Footnote *1 = Not all nondect (ND) parameters are shown in table.Footnote *2 = See Data sets in Appendices.


Footnote *3 = Jacobs Engineering Group (August 2000) Summary Report 1999 Remedial Investigation / Removal Acton, Fort Greely, Alaska.Footnote *4 = United States Geological Survey (USGS) Professional Paper 1458, “Element Concentrations in Soils and Other Surficial materials of Alaska,” 1988.


B = analyte found in associated blank as well as in sample.J = value is estimated and below quantitation limit. U = compound was analyzed for, but not detected.BK = concentration within background range.





Concentration

Frequency Detected >

ADEC Method 2 Levels




Groundwater LevelExposure Route

Exceeded


CalculationsPETROLEUM HYDROCARBONS (FUELS)

Gasoline Range Organics (GRO) mg/kg 6.3 0 / 23 1,400 1,400 300



VOLATILES

Benzene mg/kg Not Detected at 0.27 (0.14

assumed)

1 / 23 290 9 0.02 Migration to Groundwater

Toluene mg/kg 0.24 J 0 / 23 20,300 180 5.4

Xylenes (total) mg/kg 0.072 J 0 / 23 203,000 81 78


Trichloroethene (TCE) mg/kg 0.039 J 1 / 23 750 43 0.027 Migration to Groundwater

SEMIVOLATILES

Benzoic Acid mg/kg 200 J 0 / 23 410,000 390


Chrysene mg/kg 0.73 J 0 / 23 1,100 620

Fluoranthene mg/kg 0.025 J 0 / 23 4,100 2100

Fluorene mg/kg 0.013 J 0 / 23 4,100 270

2-Methylnaphthalene mg/kg 0.15 J 0 / 23 4100 43

Naphthalene mg/kg 0.074 J 0 / 23 4,100 43

Phenanthrene mg/kg 0.089 J 0 / 23 30000 4300





Concentration







Exceeded


CalculationsPyrene mg/kg 0.39 J 0 / 23 3,000 1500





Concentration

Frequency Detected Above ADEC Method 3 Alternative

Cleanup Level (ACL)


(industrial)


(industrial)



ExceededPETROLEUM HYDROCARBONS (FUELS)

Diesel Range Organics (DRO) mg/kg 1800 0 / 23 12,500 12,500 3,330

VOLATILESBenzene mg/kg Not Detected

at 0.27(0.14 assumed)

1 / 23 1970 7.4 0.114 Migration to Groundwater


Trichloroethene (TCE) mg/kg 0.039 J 0 / 23 5190 40.4 0.236PESTICIDES/INSECTICIDESBHC (a) (6) (HCH alpha) mg/kg 0.0046 0 / 30 9.06 6.08 0.02234,4-DDD mg/kg 36 0 / 30 238 6394,4-DDT mg/kg 87 0 / 30 168 6,000 1160

RCRA metalsLead mg/kg 210 0 / 23

J = estimated value





Concentration







Exceeded


CalculationsPESTICIDES/INSECTICIDES

BHC (a) (6) (HCH alpha) mg/kg 0.0046 2 / 30 1.3 5.5 0.0026 Migration to Groundwater

BHC (b) (6) (HCH beta) mg/kg 0.0053 0 / 23 4.6 43 0.009

BHC (g) Lindane (6) (HCH gamma) mg/kg 0.002 J 0 / 23 6.4 0.003

4,4-DDD mg/kg 36 1 / 30 35 47 Ingestion

4,4-DDE mg/kg 4.7 0 / 30 24 150 exceeded 1/10 of ingestion

4,4-DDT mg/kg 87 1 / 30 24 5,300 88 Ingestion

Endosulfan mg/kg 0.06 0 / 60 610 7

RCRA metals

Lead mg/kg 210 n /a No ADEC limit

Other metals

Copper mg/kg 106 0 / 23 4060 7000

J = estimated value


STEP 4:


These cleanup levels should be printed. To print, please select the print function on your web browser. This page may also be saved and emailed for documentation of the calculated cleanup levels. For best results, save the page as a "Web Archive for email" file (.mht) if your browser supports this; in Internet Explorer 5 choose "Save as..." from the file menu and change the "Saveas type" to "Web Archive for email". Other browsers should have a similar choice.



Chemical Name Chemical Type Ingestion InhalationMigration

to GW

Trichloroethylene Organic 5190 40.4 0.236


Methylene chloride

Organic 7610 132 0.0525

Lead Inorganic

HCH, a- Organic 9.06 6.08 0.0223



DDT Organic 168 6000 1160

DDE Organic 168 1980

DDD Organic 238 636

Benzene Organic 1970 7.4 0.114

Chemical Notes
























Continue

STEP 5:






Chemical Name Concentration (mg/kg) Cancer Risk Hazard

Quotient

Benzene 0.14 1.9e-7 0

DDD 36 0.0000015 0

DDE 4.7 2.8e-7 0

DDT 87 0.0000053 0.085

HCH, a- 0.0046 1.3e-8 0

Lead 210 0 0

Methylene chloride 0.24 1.9e-8 0.000038

Trichloroethylene 0.039 9.7e-9 0


10.0 REFERENCES

Alaska Department of Environmental Conservation (ADEC). (as amended through January 22, 1999). 18 AAC 75 Oil and Hazardous Substances Pollution Control Regulations.

ADEC. (March 22, 1999). Draft Guidance on Developing Soil Cleanup Levels Under Methods Two and Three.

ADEC. (September 16, 1998). Guidance On Cleanup Standards Equations and Input Parameters.

ADEC (August 9, 2000) Letter to USAED; Review of Approach Document Soil Screening Fort Greely BRAC Site 85 South, Site 133, Site 112, Site 85 North.

ADEC. (December 15, 2000). Guidance on Calculating Cumulative Risk, Final Draft.

AGRA Earth and Environmental, Inc. (May 1995). Final Remedial Design Report, Contract No. DACA85-94-D-0011, Fire Burn Pits Treatment System, Fort Greely, Alaska.

AGRA Earth and Environmental, Inc. (July 1998). Remedial Design Investigation Report, Former Fire Burn Pits, Fort Greely, Alaska, Submittal 002 - Final.

Ecology and Environment. (August 1992) Fire Training Pits Work Plan, Part 1, Fort Richardson and Fort Greely, Alaska.

Ecology and Environment. (August 1992) Fire Training Pits Work Plan, Part 2, Fort Richardson and Fort Greely, Alaska.

Jacobs. (September 1998). 1997 Site Investigation/Limited Remedial Investigation Report, Fort Greely, Alaska, Final.

Jacobs. (April 1999). 1998 Remedial Investigation Report, Fort Greely, Alaska, Final. 3 Volumes.

Jacobs. (August 2000). Summary Report, 1999 Remedial Investigation / Removal Action, Fort Greely, Alaska, Final.

Jacobs. (June 2001). Summary Report, 2000 Remedial Investigation / Removal Action, Fort Greely, Alaska, Draft.

Jacobs. (August 2001). Limited Risk Evaluation, Fort Greely, Alaska, Draft.

U.S. Army Corps of Engineers Alaska District (USAED). 1991. Groundwater Monitoring Network, Fort Greely, Alaska.

USAED. (March 7, 1994). Site Assessment / Corrective Action Plan, Three Former Fire Training Pits, Fort Greely, Alaska.


USAED. (April 1994). Environmental Assessment and Finding of No Significant Impact, Remedial Treatment of Petroleum Contaminated Soils, Fire Training Pits, Fort Greely, Alaska.

USEPA. (April 1996). Soil Screening Guidance User’s Guide. Publication 9355.4-23.

USEPA. (October 1, 1999). Region 9 Preliminary Remediation Goals (PRGs) 1999. San Francisco, California.

USEPA (August 23, 2000) Letter to USAED; EPA Comments on the Corps of Engineers Draft Approach Document Soil Screening Fort Greely BRAC: Site 85 South, Site 133, Site 112, and Site 85 North dated July 2000.

Woodward-Clyde. (January 24, 1997). U.S. Army Base Realignment and Closure 95 Program, Environmental Baseline Survey Report, Fort Greely, Alaska.