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Milan Army Ammunition Plant

Record of Decision (Finai) RECEIVED JUN 0 1 2011

Operable Unit 5 - Open Burning Ground (Soils) Milan Army Ammunition Plant DIVISION OF REMEDIATION Milan, Tennessee

April 21,2011

RESPONSE TO COMMENT FORM Date: 4/21/11 Page 1 of 5

To: Milan AAR Project Team From: (Team Organization): Army

Project Name & Location: Revised Response to USEPA Comments on the Record of Decision. Operable Unit 5. Open Burning Ground Soils (redllne version), dated October 1, 2010

Original Comments From: USEPA, dated December 9, 2010

Type of Action: • Draft Document • Risk Assessment

• Draft-Final Document • Other (Check appropriate • Final Document

boxes) Other Final (Redline version)

• Chemistry

• Geology/Hydrogeology

• Safety & Health

• Engineering

Tlie original response to l^SEPA's December 9. 2010 comments was submitted on December 23. 2010. This revised response to comments (RTC) document incoiporates revisions to Specific Comment Response No. 2 in accordance with .April 2011 email coirespondence between .Aiany (.ARC.ADIS). l^SEP.A. and TDEC. Please also note that Eigure 2-5 was revised in accordance with various Tier 1 team meeting discussions and related coirespondence since the October 1. 2010 submittal of the ROD (redline version).

In order to expedite the response and review process. .Ann\ *s responses to l^SEP.A comments are provided in texl directly below each l^SEP.A comment in bold, italicized font. Please note that throughout the review process, several comments have been made to the general description of Ll^Cs included in Section 2.12.2.2. Based on review of all of these comments, the .Amiy proposes the below changes to the bullets. Some of these changes are also addressed within the response to EP.A comments below.

Erom Section 2.12.2.2

Tlie following generally describes the Ll^Cs that will be implemented at Ol^5 OBG to achieve the aforementioned Ll^C objectives:

• Incoiporating the LIX' boundaiy and land use restrictions for Ol^5 OBG into the installation's Liind INe Control Plan (and any other relevant documents governing land use at M.A.AP).

• Ihilizing the facility Dig Restrictions process to require review approval and implementation of worker protection practices before any intrusive activities are perfonned at the Site.

• Posting signs adjacent to caps advising that any excavation activity must be authorized in advance by the responsible environmental department. Tlie size, location, iind content of the signs will be specified in the Ll^CTP.

Page 1

A Notice of Asbestos Disposal as specified in TDEC 1200-3-ll-.02(2)(l)(5) will be recorded in the County Register of Deeds. Maintaining Ll^Cs boundaiy with signage, existing OBG access gate, and existing site restrictions and conducting routine inspections in accordance with the Ll^CIP to prevent unauthorized access. In the event iiny portion of Ol^5 OBG is tninsfeired. additional security measures will he applied as needed.

In the event any portion of Ol^5 OBG is transfeired. the requirements of Tennessee Code .Annotated (TC.A) §-68-212-225 will he followed.

l^SEP.A General Coiiunents;

1. Tlie .Ai'iny has done a good job of addressing most of earlier EP.A Comments. Changes to the Draft Einal ROD generalK' follow the EP.A "Guicle to Preparing SuperfuncIProposed Plans. Record of Decision, and Other Remedy Selection Decision Doctiments" (OSW'ER 9200.1-23P July 1999).

Army Response: Army appreciates EPA's feedback. Please also note that the bnlleted numbering of the following Specific Comments was inaccurate due to an extra bullet inserted within the text of Specific Comment five. This minor formatting error was corrected and therefore, the actual number of Specific Comments (ten) is now shown.

USEP.A Specific C'oininents;

2. . Section 1.2. Remedv Selection. .As stated in EP.A earlier Comments, revise this sentence to reflect that both the .Amiy and the EP.A jointly select the remedy at federal facilities as required by CERCL.A 120 and the NCP at 40 CER 300.430(f^(4)(iii)(.A). Tlie Tennessee Department of Environment iind Conservation (TDEC) concurs with the Selected Remedy."

Army Response: Paragraph two of Section 1.2 was replaced with the following paragraph as agreed upon by Army. USEPA. and TDEC in email correspondence between April 4. 2011 and April 11. 2011.

"The United States Environmental Protection Agency (USEPA) and the Tennessee Department of Environment and Conservation (TDEC) concur with the information and basis for the remedy as described in this ROD. As required in the .\CP at 40 CER 300.430(f)(4)(iii)(A). the Army and the USEPA jointly selected the remedy. The selected remedial action was agreed upon by the United States Army (Army), the USEPA. and the TDEC. as mandated by the Federal Facility Agreement for MAAP. executed pursuant to CERCLA 120."

3. Page 3. Section 1.2. Remedv Selection. Revise sentence to indicate that TDEC "concurs with or approves" the remedy iind remove reference to EP.A which selects the remedy along with the .Amiy as noted above.

Page 2

Army Response: Please see response to Specific Comment 2.

4. Page 38. Section 2.12.2.2. Ll^Cs. Consistent with NCP language and EPA Ll^C Checklist, replace the word 'acceptable* with 'unlimited* in the tlrst sentence of the fourth paragraph.

Army Response: The word 'acceptable' was rejflaced with 'unlimited' as requested.

5. Page 39. Section 2.12.2.2. Ll^Cs 4"' bullet. Tlie Notice of Asbestos Disposal should be recorded after construction of the caps consistent with TDEC regulations. The EE.A parties can detennine the timeframe for recordation after remedy implementation and provide in the Ll^CIP. The Notice is not considered a property use restriction that encumbers federal property, it is just a notation in the property records. Consequently, the bullet should be revised to remove the text "In the event any portion of 01^5 OBG is transfeiTcd to a private entity.'* and would read as follows:

6. A Notice of Asbestos Disposal as specified in TDEC 1200-3-11-.02(2)(1)(5) will be recorded in the County Register of Deeds.

Army Response: The text "In the event any portion of 0U5 OBG is transferred to a private entity" was deleted as requested.

1. Page 39. Section 2.12.2.2. Ll^Cs 6"' and bullets. Transfer of property title to both private and governmental entities (e.g.. county or city government) would require that legally enforceable use restrictions in the Notice of Land INe Restrictions as well as the deed. Base closure or excess of federal property often involve triinsferto local government entities. .Accordingly, revise texl in the bullets as follows: "In the event any portion of 01^5 OBG property is transfeired... .'*

Army Response: Army agrees with deleting references to 'private entity' in order to not exclude potential future transfer to government entities. In addition, due to multiple comments received regarding these specific bullets and as presented above, the Army is proposing to replace the 6^ and bullets and the sentence after the bullet list with the following bullet:

• In the event any portion of 0U5 OBG is transferred, the requirements of Tennessee Code Annotated (TCA) §-68-212-225 will be followed.

Including the reference to TCA §-68-212-225 addresses the intent of both the and 7^ bullets and incorporates the language from the sentence after the bullet list.

Therefore the following tivo bullets (6"' and ?"') and sentence will be deleted:

• In the e\'ent any portion of 0U5 OBG is transferred to a private entity, recording a .\otice of Land Use Restrictions in the Count}' Register of Deeds.

Page 3

• In the e\'ent any portion of 0U5 OBG is transferred to a private entity, land use restrictions consistent with LUC Objectives will be included in the deed and/or lease.

The notice of land use restrictions will be filed in accordance with Tennessee Code Annotated (TCA) §-68-212-225.

8. Page 40. Section 2.12.3 Ll^Cs. Revise second sentence to indicate that Ll^C inspections will be conducted in accordance with an approved Ll^CIP as well as the MAAP land use controls program. This is consistent with language above on Page 38.

Army Response: As requested, the referenced sentence has been revised as follows: "...LUC inspections will be conducted annually in accordance with an approved LUCIP and the site-wide MAAP land use controls program. "

9. Page 45. Section 2.12.7 Five Year Reviews. Wording is not entirely consistent with NCP language. Revise text to remove the word 'potentially* and add the following after the tenn 'hazardous substiinces*. "pollutants, or contaminants.". See Section 1.5 of the ROD for similar use of the language.

Army Response: As requested, the referenced sentence has been revised as follows: "...since hazardous substances, pollutants, or contaminants will remain at the site above levels that allow for unlimited exposure and unrestricted use. "

10. 2. CL. 5. LlX's. Section 2.12.2.2. 3rd paragraph. RegiU'ding the placards- do you mean signs? We are not clear whether there is a distinction .Also, you will need to establish a deadline for placement and details (wording, spacing, etc). Believe it or not. we have actually had disputes on this! You may place this detail in the ROD if you like but typically it is placed in the Ll^CTP. You could address this by adding "placards" or "signs" to the nexl sentence describing the implementation actions to be described in the LITCTP.

Army Response: As requested, the referenced sentence has been revised as follows: "Placards (Le signage) prohibiting disturbance of capped areas will be installed. The LUC implementation actions, including signage, monitoring and enforcement requirements, will be provided in a LUC Implementation Plan (LUCIP)... "

11. 3. CL 6. Section 2.12.2.2. 4th paragraph. Please delete "LLCs will be maintained until the concentrations of hazardous constituents in soil are at such levels to allow uni'estricted use iind acceptable exposure to OBG soil." Tins confticts with the duration language in the tlrst piii*agraph. last sentence, of this section.

Army Response: This comment conflicts with Comment 4 and therefore this sentence will not be deleted as requested. Instead the word 'acceptable' has been replaced by the word 'unlimited' as requested in Comment 4.

Page 4

12. 4. CL 9. Section 2.12.2.2. 3rd paragraph, please modify the following statement to make it completely clear that the Ll^ClP IS a primaiy document under the FF.A. .AJI acceptable approach would be to say: "Within 90 days of ROD signature, the .Ajiny will submit to the l^SEP.A for review and approval a Ll^ClP. as pail of the Remedial Design, that will contain implementation and maintenance actions, including periodic inspections."

Army Response: The referenced sentence was revised as requested by inserting the words 'as part of the remedial design.'

Page 5

Record of Decision (Final)

Operable Unit 5 - Open Burning Ground (Soils)

Milan Army Ammunition Plant

Fi-|.:ii-.| |.,

ARCADISU.S., Inc. 2849 Paces Ferry Road Suite 400 Atlanta Georgia 30339 Tel 770.431.8666 Fax 770.435.2666

VUI F-I

GP1MILAN/Rpt2582

Aprll 21. 2011

This document is intended oniy for the use of the individuai or entity for which it was prepared and may contain information that is priviieged. confidentiai and exempt from disciosure under appiicable /aw. Any dissemination, distribution or copying of this document is strictiy prohibited.

Table of Contents

1. Declaration

1.1 Site Name and Location

1.2 Statement of Basis and Purpose

1.3 Assessment of the Site

1.4 Description of the Selected Remedy

1.5 Statutory Determinations

1.6 ROD Data Certification Checklist

1.7 Authorizing Signatures

2. Decision Summary

2.1 Site Name, Location, and Description

2.2 OBG Site History and Enforcement Actions

2.3 History of Site Investigations

2.4 Community Participation

2.5 Scope and Role of Operable Unit or Response Action

2.5.1 CU5 Interim Actions and Decision Documents

2.5.2 Change in Remedial Approach

2.5.3 Final Response Action

2.6 Site Characteristics

2.6.1 OBG Area Topography and Geology

2.6.2 Nature and Extent of Contamination

2.6.2.1 Development of COCs

2.7 Current and Potential Future Land and Resource Uses

2.7.1 Current and Anticipated Future Land Use

2.7.2 Surrounding Land Use

2.7.3 Current Groundwater Use

2.8 Summary of Site Risks

2.8.1 Potential Risks to Human Health

2.8.2 Potential Risks to the Environment

3 3 3 4 4 5 6 6

7 7 8 9 10 12 13 13 15 16 16 16 18 19 19 20 20 21 21 24

Table of Contents

2.8.3 Protection of Groundwater 24

2.8.4 Basis for Action 25

2.9 Remedial Action Objectives 25

2.10 Description of Remedial Alternatives 26

2.10.1 Alternative A: No Action 26

2.10.2 Alternative B: Limited Action 27

2.10.3 Alternative C: Engineered Caps (original asphalt-based alternative) with LUCs 27

2.10.4 Alternative F: Engineered Cap with GCL and Vegetative Cover with LUCs 28

2.11 Summary of Comparative Analysis of Alternatives 29

2.11.1 Overall Protection of Human Health and the Environment 30

2.11.2 Compliance with ARARs 30

2.11.3 Long-Term Effectiveness and Permanence 31

2.11.4 Reduction of Toxicity, Mobility, or Volume Through Treatment 32

2.11.5 Short-Term Effectiveness 32

2.11.6 Implementability 33

2.11.7 Cost 33

2.11.8 State Acceptance 34

2.11.9 Community Acceptance 34

2.12 Selected Remedy 34

2.12.1 Summary of Rationale for Selected Remedy 34

2.12.2 Description of the Selected Remedy 35

2.12.2.1 Engineered Caps 35

2.12.2.2 Land Use Controls 37

2.12.3 Performance Monitoring Strategy 39

2.12.4 Summary of Estimated Remedy Costs 39

2.12.5 Expected Cutcome of the Selected Remedy 40

2.13 Statutory Determinations 40

Table of Contents

2.13.1 Protection of Human Health and the Environment

2.13.2 Compliance with ARARs

2.13.3 Cost-Effectiveness

2.13.4 Utilization of Permanent Solutions and Alternate Treatment Technology

2.13.5 Preference for Treatment as a Principal Element

2.13.6 Wastes Remaining on Site

2.13.7 Five-Year Review Requirements

2.13.8 Documentation of Significant Changes

3. Responsiveness Summary

3.1.1 Stakeholder Issues and Lead Agency Responses

3.1.2 Technical and Legal Issues

3.1.3 Summary of Comments and Responses

4. References

40 41 42

43 43 43 44 44

44 44 45 45

45

Tables Table 2-1 Summary of Residential Risks and Hazards for Constituents of

Concern in Soil at the OBG

Table 2-2 Baseline Risk Summary

Table 2-3 List of Retained Constituents of Concern for Risk Evaluations -OBG Area Soil and Groundwater

Table 2-4 Risk Characterization Summary for Residential Adults and Children - Carcinogens

Table 2-5 Risk Characterization Summary for Residential Children - Non-Carcinogens

Table 2-6 Risk Characterization Summary for Residential Adults - Non-Carcinogens

Table 2-7 Comparative Analysis of Alternatives

Table 2-8 Cost Estimate for Alternative F: Engineered Caps (GCL-Based)

Table 2-9 ARARs and TBCs for the Selected Remedy

Table of Contents

Figures

Figure 1-1 Site Location Map

Figure 2-1 Site Map

Figure 2-2 Risk Assessment Conceptual Site Model

Figure 2-3 Conceptual Layout of Remedial Actions

Figure 2-4 Conceptual Cap Design

Figure 2-5 Extent of Land Use Controls at the OBG

Record of Decision


Acronym List

ABA Ammunition Burnout Area

ACM Asbestos-containing material

ADA Ammunition Destruction Area

ARAR Applicable relevant and appropriate requirements

ARCADiS ARCADiS U.S., inc.

ASA Ammunition Storage Area

ATA Ammunition Test Area

bgs Belowground surface

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CERCLIS Comprehensive Environmental Response, Compensation, and Liability Information System

COC Contaminant of concern

CSM Conceptual Site Model

ELCR Excess Lifetime Cancer Risk

ERA Ecological Risk Assessment

FADA Former Ammunition Destruction Area

FFA Federal Facility Agreement

FS Feasibility Study

FSA Feasibility Study Addendum

GCL Geosynthetic clay liner

HI Hazard index

HO Hazard quotient

HRA Human Risk Assessment

LUC Land use control

LUCIP Land Use Controls Implementation Plan

MAAP Milan Army Ammunition Plant

MC Munitions constituents

mg/kg Milligrams per kilogram

NCP National Contingency Plan

NPL National Priorities List

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Record of Decision


OBG Open Burning Ground

OU Operable unit

PBS&J Post, Buckley, Schuh and Jernigan, inc.

RAB Restoration Advisory Board

RAO Remedial Action Objectives

RCRA Resource Conservation and Recovery Act

RDX Cyclotrimethylenetrinitramine

RG Remedial goal

Ri Remedial investigation

ROD Record of Decision

SARA Superfund Amendments and Reauthorization Act

SRI Supplemental Remedial Investigation

SSA Southern Study Area

TDEC Tennessee Department of Environment and Conservation

TNT Trinitrotoluene

USAGE United States Army Corps of Engineers

USAEC United States Army Environmental Command (formerly USATHAMA)

USATHAMA United States Army Toxic and Hazardous Materials Agency

USEPA United States Environmental Protection Agency

UXO Unexploded ordnance

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Record of Decision Operable Unit 5 - Open Burning Ground (Soils)

1. Declaration

1.1 Site Name and Location

This Record of Decision (ROD) addresses remedial actions for Operable Unit 5 (OU5), also known as the Southern Study Area (SSA), at the Milan Army Ammunition Plant (MAAR), located in Gibson and Carroll counties, Tennessee (Figure 1-1). The SSA consists of all portions of the facility south of Route 54. The 2001 Feasibility Study (FS) and the 2010 FS Addendum (FSA) and Supplemental Remedial Investigation (SRI) identified areas where soil remediation is required for the portion of OU5 referred to as the Open Burning Ground (OBG). Groundwater contamination in this OU will be addressed by a separate ROD. The Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) identification number for MAAR is TN0210020582.

1.2 Statement of Basis and Purpose

This decision document presents the Selected Remedy for contaminated soils for the applicable portions of OU5 (the OBG area) at the MAAP facility located in Milan, Tennessee. The Selected Remedy presented in this ROD addresses the four explosives-impacted areas in the OBG requiring remediation, as identified in the 2001 Final Feasibility Study. The Selected Remedy was chosen in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA) and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCR). This decision is based on the Administrative Record file for this site.

The United States Environmental Protection Agency (USEPA) and the Tennessee Department of Environment and Conservation (TDEC) concur with the information and basis for the remedy as described in this ROD. As required in the NCR at 40 CFR 300.430(f)(4)(iii)(A), the Army and the USEPA jointly selected the remedy. The selected remedial action was agreed upon by the United States Army (Army), the USEPA, and the TDEC, as mandated by the Federal Facility Agreement for MAAP, executed pursuant to CERCLA 120.

This ROD supersedes the 2004 Interim Record of Decision (IRCD) and the 2007 Explanation of Significant Differences (ESD) previously issued for CU5 OBG soils and represents a change to a previously selected remedy as described in Section 2.5.

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1.3 Assessment of the Site

A number of environmental investigations have been performed at the OBG over the past three decades. As discussed in Section 2.8 (Summary of Site Risks), a human health risk assessment originally performed as part of the 1999 Remedial Investigation (Rl) determined that human health risks at OU5, including the OBG, the Former Ammunition Destruction Area (FADA), the Current ADA, the Ammunition Test Area (ATA), the Ammunition Storage Area (ASA), the Closed Ammunition Burnout Area (ABA), and the Closed Sanitary Landfill, based on current and reasonably anticipated future land use (site workers, farmers, and hunters), are within acceptable risk ranges. This risk assessment was reevaluated in 2010 following USEPA's request to include the hypothetical future residential receptor scenario. The updated risk evaluation indicated that residential exposure to soils at the OBG and FADA would result in unacceptable levels of risk. In addition, the soils may continue to serve as a source of groundwater contamination if no action is taken. Also discussed in Section 2.8, a reevaluation of the original ecological risk assessment presented in the 1999 Rl reaffirmed that ecological risks were not significant.

In summary, the risk evaluation conducted as part of the Rl and Feasibility Study (FS) phases of work concluded that remedial action is required to protect potential future residents against direct exposure to contaminated soils and to protect groundwater quality at the OBG. The response action selected in this Record of Decision is necessary to protect public health and welfare or the environment from actual or potential releases of hazardous substances into the environment that may potentially present an endangerment to public health or welfare.

1.4 Description of the Selected Remedy

The Selected Remedy is designed to remediate OBG area soils that contain explosives constituents at concentrations that exceed risk-based remedial goals (RGs).

The major components of the Selected Remedy are:

• Containment/capping of RDX/TNT contaminated soils to prevent direct contact and to protect groundwater

• Consolidation under capped areas of asbestos containing waste materials that may be encountered in the surface soils.

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• impiementatlon and maintenance of land use controis (LUCs) by the Army to prevent direct contact with contaminated soil and to restrict land use to prevent residential, agricultural and recreation use at the site. Periodic inspections will be conducted to verify continued implementation of the LUCs.

• Maintain the integrity of any existing or future monitoring or remediation system including, but not limited to, the capped areas.


The Selected Remedy is protective of human health and the environment, complies with federal and state requirements that are legally applicable or relevant and appropriate to this remedial action, and is a cost-effective application of public funds. The remedy utilizes permanent solutions and alternative treatment technologies to the extent practicable while maintaining a work environment that is safe for remediation workers. Treatment technologies that include excavation, mechanical separation of soil and UXO, or detonation in place of UXO items as a component of the remedy may have greater permanence or greater utilization of alternative technologies; however, these alternatives were determined to be unimplementable because of the risks associated with comingled UXO and suspected ACM.

The Selected Remedy does not satisfy the statutory preference for remedies that employ treatment as a principal element because of the inability to safely handle media containing comingled UXO and suspected ACM. Treatment technologies that include excavation or mechanical separation of soil and UXO, or possess the potential for unintentional detonation of UXO items where ACM may be present, are unimplementable because of the increased health risks to site workers. As a result, the principal element of the Selected Remedy is containment. With proper monitoring and maintenance, the Selected Remedy will provide a safe and effective final remedy for impacted OU5 OBG area soils.

Because the remedy will result in hazardous substances, pollutants, or contaminants remaining above levels allowing for unrestricted use and unlimited exposure, in accordance with Section 121(c) of CERCLA and 40 CFR 300.430(f)(4)(ii), a statutory review will be conducted every five years after initiation of the selected remedial action and continuing every five years thereafter unless and until use and exposure may be allowed to ensure that the remedy remains protective of human health and the environment.

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1,6 ROD Data Certification Checklist

The following information is induded in the Oedsion Summary section of this Record of Decision. Additional information can be found in the Administrative Record file for this site.

Chemicals of concern and their respective concentrations Section 2.8

Baseline risk represented by the chemicals of concem Sections 2.8.1 and 2.8.2

Cleanup levels established for chemicals of concem and the basis for these levels

Section 2.9

Current and reasonably antidpated future land use assumptions and current and potential future beneficial uses of groundwater used In the baseline risk assessment and the ROD

Section 2.7

Potential land and groundwater use that will be available at the site as a result of the Selected Remedy

Sections 2.9 and 2.12

Estimated capital, annual operation and maintenance costs, and the number of years over which the remedy cost estimates are projected

Table 2-8

Key factors that led to selecting the remedy Sections 2.8,2.9,2,10,2,11, and 2,12

1.7 Authorizing Signatures

Scott D. Kimmell Colonel, U.S. Army Environmental Command Commanding

E. Hill, Director Superfund Division U.S. Environmental Protection Agency, Region IV

Robert A. Binford, Director Division of Remediation Tennessee Department of Environment and Conservation

Date

Date

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2. Decision Summary

2.1 Site Name, Location, and Description

MAAP Is located in portions of Gibson and Carroll counties in western Tennessee as shown on Figure 1-1. The City of Milan is immediately to the west of MAAP and is approximately 50 miles east of the Mississippi River. MAAP is bordered on the northeast and east by land owned by the Tennessee National Guard Bureau, on the west and northwest by land owned by the City of Milan and the University of Tennessee, and on the north and south by privately owned farm land. MAAP was placed on the National Priorities List (NPL) on July 22, 1987. The CERCLIS identification number for this site is TN0210020582. The U.S. Army is the lead agency for developing and preparing this ROD.

MAAP began operation in 1942 and is currently an active Army installation (or post) with the mission of loading, assembling, packaging, storing, and shipping medium- and large-caliber ammunition. The post covers approximately 22,420 acres and includes 10 ammunition load, assemble, and package (LAP) lines; one washout/rework line; one central x-ray facility; one test area; two shop maintenance areas; 16 permitted hazardous waste storage areas (14 permitted magazine container storage igloos, one container storage building for non-explosive wastes, and one explosive waste transfer facility),; a demolition and burning grounds area; and an administrative area In addition, there are seven industrial wastewater treatment facilities (IWTFs). Administrative support, storage and disposal facilities, and active and inactive production facilities are dispersed among wooded areas and cultivated fields.

For the installation restoration strategy, MAAP has been divided into five operable units (OUs): GUI, OU2, OU3, OU4, and OU5 (Figure 1-1). OU5, also known as the SSA, consists of all portions of the facility south of Route 54 and consists of subareas generally associated with the OBG, the FADA, the Current ADA, the ATA, the ASA, the Closed ABA, and the Closed Sanitary Landfill. This ROD addresses contaminated soils at the OBG (Figure 1 -1) because the OBG was the only OU5 subarea identified during the RI/FS as posing an unacceptable risk to human health or the environment. Historical investigations and feasibility studies identified the need to address contaminated soils at the OBG portion of OU5; therefore, this ROD addresses soil media at this area.

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2.2 OBG Site History and Enforcement Actions

The OBG reportedly has been in use since the beginning of operations at MAAP in 1942. The OBG consists of approximately 114 acres and has been used for the destruction and disposal of reject munitions and explosives-contaminated wastes (Figure 2-1). Based on the findings of historical remedial investigations, various types of munitions produced at MAAP, or their components, may have been discarded in the OBG. Three general categories of waste reportedly have been disposed of at the OBG since 1942: bulk explosives (explosives not containerized in munitions), ordnance components (e.g., defective ordnance, ordnance components damaged during assembly at MAAP, or ordnance items removed from storage facilities), and wastes potentially contaminated with explosives (Post, Buckley, Schuh and Jernigan, Inc. [PBS&J], 1988).

Bulk explosives reportedly were burned on the ground surface at the OBG, with the resulting ash disposed of in natural gullies or excavated trenches. Ordnance items and explosives-contaminated wastes were routinely discarded in trenches at the OBG with ash from the burning of bulk explosives. Trench excavations are reported to be no deeper than 15 feet. Debris, ordnance, and ash were dumped from trucks at the sides of the trenches with the contents burned periodically until the excavation was filled and then covered with soil (PBS&J, 1988).

Industrial activities associated with the mission of MAAP have resulted in the contamination of soils and groundwater by various explosives constituents consisting of bulk explosives, impurities from their manufacture, associated environmental degradation products, and other hazardous constituents from ordnance production. Soil contamination in the OBG consists primarily of elevated concentrations of cyclotrimethylene-trinitramine (RDX) located within the top 2 feet of ground surface (ARCADIS, 2010a). While the effects of elevated trinitrotoluene (TNT) in soil were not modeled, it was later added as a contaminant of concern (GOG) to be consistent with the GU3/GU4 ROD.

Facility operations changed in late 1983 as a result of Resource Conservation and Recovery Act (RCRA) and Tennessee Hazardous Waste Rules and, in response to these rules, MAAP ceased the practice of open burning and/or burying explosives-contaminated waste. Current operations at the GBG are in accordance with the facility RCRA operating permit and primarily include burning and flashing of explosives-associated media placed in metal flash pans and mounted on concrete pads.

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M AAP was placed on the NPL in 1987. The Department of the Army (DA), USEPA, and the State of Tennessee signed a CERCLA Federal Facility Agreement and Consent Order (FFA) in 1989 to establish a formal framework by which all signatory parties will proceed with investigation and subsequent cleanup of MAAP. Execution of the FFA is a requirement of CERCLA Section 120.

2.3 History of Site investigations

A number of environmental investigations have been performed at the OBG area over the past three decades. The ROD for OBG soils is based on information presented in greater detail in the following reports:

• 1981 Milan Army Ammunition Plant Contamination Survey Report prepared by the U.S. Army Toxic and Hazardous Materials Agency (USATHAMA)

• 1988 Final Report Investigation and Engineering Analysis for Remedial Actions at the Milan Army Ammunition Plant Open Burning Grounds prepared for the U.S. Army Corps of Engineers (USACE) by PBS&J

• 1991 Remedial Investigation for Milan Army Ammunition Plant prepared for USATHAMA by ICF Kaiser Engineers, Inc.

• 1999 Final Remedial Investigation, OU5, Southern Study Area Soils, Milan Army Ammunition Plant prepared for the U.S. Army Environmental Center (USAEC) by Fluor Daniel, Inc.

• 2001 Final Feasibility Study for Operable Unit 5, Southern Study Area prepared for USACE, Mobile District, by Harding ESE, Inc.

• 2004 Draft Final Operable Unit 5 Interim Record of Decision, prepared for the U.S. Army by ARCADIS

• 2007 Explanation of Significant Differences for Operable Unit 5 - Open Burning Ground and Former Ammunition Disposal Area Soils, prepared for the U.S. Army by ARCADIS

• 2008 Operable Unit 5 Technical Memorandum - Findings from Characterization of Potential Asbestos-Containing Material, Milan Army Ammunition Plant prepared for the U.S. Army by ARCADIS

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• 2009 Operable Unit 5 Technical Memorandum - Evaluation of Historical Boring Data, Milan Army Ammunition Plant prepared for the U.S. Army by ARCADIS

• 2010 Final Feasibility Study Addendum and Supplemental Remedial Investigation Report prepared for the U.S. Army by ARCADIS

• 2010 Final Proposed Plan prepared for the U.S. Army by ARCADIS

This ROD supersedes the 2004 IROD and the 2007 ESD previously issued for 0U5 OBG soils and represents a change to a previously selected remedy as described in Section 2.5.

2.4 Community Participation

The public participation requirements in CERCLA and the NOP were followed and implemented in the remedy selection process. Throughout the RI/FS process, the community was updated via periodic Restoration Advisory Board (RAB) meetings. The RAB at MAAP was established in July 1994 as a forum for exchange of information and partnership among local citizens, MAAP, USEPA, and TDEC. Most importantly, the meetings provide a convenient forum for the community to provide input on the cleanup process.

The Administrative Record file and information repository are maintained at the U.S. Army Environmental Office at MAAP. An electronic copy of the information repository is also maintained at the Mildred G. Fields Memorial Library in Milan, Tennessee. Finally, an information repository was made available to the public via the internet (http:/Avww.mllanaap-ar.com/) in 2004 to broaden community access to site files related to cleanup activities at MAAP.

NCP §300.430(f)(3)(i) requires the lead agency to do the following after preparation of the Proposed Plan and review by the support agency:

• Publish a notice of availability and brief analysis of the Proposed Plan in a major local newspaper

• Make the Proposed Plan and supporting analysis and information available in the Administrative Record file

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• Provide a reasonable opportunity, not less than 30 calendar days, for submission of written and oral comments on the Proposed Plan and the material contained in the Administrative Record file

• Provide the opportunity for a public meeting to be held during the public comment period

• Keep a transcript of the public meeting held during the public comment period and make such a transcript available to the public

• Prepare a written summary of significant comments, criticisms, and new relevant information submitted during the public comment period and the lead agency response to each issue. The Responsiveness Summary must be available with the ROD.

The requirements of NCR §300.430(f)(3)(i) were met as described in the following paragraphs. The Draft Final Proposed Plan was made available to the public in April 2010. It can be found in the Administrative Record file and the information repository, along with the Final Rl, OU5, Southern Study Area Soils, Milan Army Ammunition Plant (Fluor Daniel, 1999); the Final PS for the Southern Study Areas of Operable Unit 5 (Harding ESE, 2001); and the Final PSA/SRI Report (ARCADIS, 201 Oa). Notices of availability of the Administrative Record file documents were published in the Milan Mirror-Exchange, the Jackson Sun, and the Carroll County News Leader in April 2010. The Final Proposed Plan was not available prior to the public meeting; accordingly, the Draft Final Proposed Plan was made available to the public in April 2010, with the concurrence of USEPA and TDEC. A public comment period was held from April 28, 2010 to May 28, 2010, and a public meeting was held on May 6, 2010 to present the Proposed Plan to the community. The Proposed Plan was finalized in October 2010 and added to the administrative record file; no substantive revisions were made to the Proposed Plan following the public comment period. No comments were received during the public comment period as described in the Responsiveness Summary, which is included as Section 3 of this Record of Decision.

The public participation requirements of CEROLA and the NOP were met as summarized in the following chronology of community participation activities related to the remedy selection process for the OBG soils of OU5:


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Activity Information Provided Forum When

Remedial Investigation

Status Updates RAB Meeting Periodically between 11/96 and 1/99

Remedial Investigation

Presented Final RI RAB Meeting 3/18/99

Feasibility Study

Draft and Draft Final FS

RAB Meeting 4/20/00 and 11/29/00 Feasibility Study

Draft and Draft Final FS Addendum

RAB Meeting 8/6/09 and 3/4/10

Feasibility Study

Final FS Addendum and Supplemental RI

RAB Meetings, Newspapers, Public Meeting

3/4/10, 4/27/10, 5/6/10

Proposed Plan (Draft Final)

Notice of Availability Newspapers 4/27/10 Proposed Plan (Draft Final)

Opportunity to Comment

Public Comment Period 4/28/10 to 5/28/10

Proposed Plan (Draft Final)

Opportunity to Comment

Public Meeting 5/6/10

Fact Sheet for Proposed Plan

Presented Public Comment Meeting 5/6/10

Proposed Plan (Final)

Presented Administrative Record File 12/22/10

The risk assessment for the OBG was reevaluated in 2010 as part of the Final PSA/SRI Report and included the current use and hypothetical future residential receptor scenario. This information was presented to the public within the Proposed Plan and during the public meeting held on May 6, 2010.

2.5 Scope and Role of Operable Unit or Response Action

Historical OU5 remedial investigations evaluated potential contamination source areas within the SSA, including the:

• Open Burning Ground

• Former Ammunition Destruction Area

• Current Ammunition Destruction Area (active operation)

• Ammunition Test Area

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• Ammunition Storage Area

• Closed Ammunition Burnout Area

• Sanitary Landfill

Subsequent feasibility evaluations (as presented in the FS and PSA/SRI reports) concluded that remedial actions to protect human health, the environment, and groundwater are required for soils in the OBG subarea of OU5.

2.5.1 0U5 Interim Actions and Decision Documents

During the RI/FS efforts at OU5, several interim actions/decision documents were completed at OU5. These include:

• A No Further Action ROD for two areas in 1998: the Closed ABA and the Sanitary Landfill.

• Removal of lead-contaminated soils from the base of a group of water towers. After completion of this removal action, it was determined (1997) that No Further Action was required for the water towers.

• A time-critical removal was completed for the railyard at Building Y-103 in 2002 in accordance with a 1999 engineering evaluation/cost analysis.

2.5.2 Change in Remedial Approach

This ROD supersedes an IROD and an BSD already issued to address contaminated soils within the OU5 OBG. The three major elements of the remedy selected in the 2004 IROD included: performing in-situ bioremediation using land farming techniques, developing a post-remediation cover of natural vegetation, and establishing both physical and administrative LUCs. In 2007, an BSD was issued to support implementation of the IROD contingency remedy of excavation and onsite ex-situ remediation as a result of observations of potential UXO in the target remediation areas.

The excavation/ex-situ treatment remedy documented in the BSD could not be safely implemented due to the discovery of isolated pieces of asbestos at OBG (comingled with existing UXO) during field activities that began in April 2007. As a result, remedial

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alternatives for OBG soils were reevaluated in the 2010 Feasibility Study Addendum and Supplemental Remedial Investigation Report and a new remedy consisting of containment, vegetative cover, and LUCs was retained as the Preferred Alternative for OU5 OBG soils remediation as presented in the Final Proposed Plan. The Preferred Alternative was retained following the completion of a public meeting and response to comment period. A summary of the activities leading to selection of the containment remedy presented in this ROD is provided below.

• An Interim Record of Decision (IROD) was prepared in 2004 for the originally Selected Remedy which consisted of in-situ bioremediation (i.e. land farming), vegetative cover, and LUCs.

• Supplemental field characterization efforts were performed in 2005 to refine the volumes of soil that required remediation in support of the IROD. Visual observations of potential UXO in the target remediation areas presented a safety hazard for the land farming techniques used in the selected remedy.

• An BSD was published in 2007 to support implementation of the contingency remedy (excavation and ex-situ treatment at the composting facility) based on field observations.

• The contingency remedy was initiated in April 2007; however, field activities were halted after potential asbestos-containing material (ACM) was discovered at one of the remediation areas. Initial samples of potential ACM confirmed that material observed in one OBG remediation area contained non-friable asbestos.

• Additional field visual inspections of the OBG area for ACM were performed in April 2008, and samples of potential ACM confirmed the presence of non-friable asbestos in, or in close proximity to, several OBG remediation areas. The comingled presence of ACM with potential UXO significantly complicated safe and effective implementation of excavation/composting remedy initiated at the OBG. As a result, the Army initiated evaluation of alternative remedies.

• The Feasibility Study Addendum and Supplemental Remedial Investigation Report was prepared in 2009-2010 for the following key purposes: 1) to present a summary of field activities completed since the 2001 FS, 2) to provide a basis for reevaluating the previously developed remedial alternatives, and 3) to develop and present a revised alternative.

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• The 2010 Final Feasibility Study and Supplemental Remedial Investigation Report selected containment with LUCs as the Preferred Alternative.

2.5.3 Final Response Action

In summary, the results of historical RI/FS efforts indicate that remedial actions are required for soil media in the OBG portion of OU5. This ROD, therefore, focuses on this area and media. The remedy will also result in mitigating potential impact from explosive compounds into groundwater in the OU5 area. However, this area of groundwater will be evaluated under a separate response action and will be addressed in a separate ROD.

This ROD presents the final response action for OU5 OBG soils through a remedy of containment (capping) and LUCs. The planned sequence of actions for implementation of the Selected Remedy (containment with LUCs) would generally include the following:

1. Performing an unexploded ordnance (UXO) avoidance sweep of the remedial areas followed by clearance of UXO items (if required) that may restrict the ability to safely place a base course of fill material

2. Collecting additional soil samples in the areas with RDX levels above 10 milligrams per kilogram (mg/kg) (action criteria) to further refine the limits of the cap

3. Visually inspecting the revised limits of the cap and visually assessing the surrounding area for asbestos-containing material (ACM) at the ground surface

4. Removing any ACM identified in proximity to the newly defined cap boundary and manually relocating this media to a location within the capped areas

5. Performing confirmation sampling beneath surficial ACM identified beyond capped areas in accordance with published USEPA guidance to assess the completeness of the ACM relocation effort

6. Constructing the engineered caps over the areas identified in the PSA

7. Implementing LUCs to prevent direct contact with site soils, restrict land use from transfer and development for residential use, and further improve remedy effectiveness and permanence



8. impiementlng periodic inspection and maintenance events to maintain the long-term integrity and performance of the caps

The use of engineered caps and LUCs will reduce or eliminate direct exposure to contaminated soil, protect groundwater by reducing percolation of precipitation through impacted soil, and protect surface water by stabilizing eroding areas.

2.6 Site Characteristics

This section provides an overview of the site characteristics affecting soil contamination of the OU5 OBG, including the nature and extent of contamination.

2.6.1 OBG Area Topography and Geology

The OBG is situated in the east-central portion of MAAP on a topographic high point of the installation. The OBG area consists of approximately 114 acres characterized by open fields separated by stands of pine trees and hardwoods. Gravel roads prevail in the OBG area to support the daily activities of employees processing spent or off-specification ordnance items or conducting burning operations. The aerial photograph shown on Figure 2-1 illustrates the vegetation, roads, and buildings present at the OBG area. The land in the OBG area is well drained and wet areas are seldom present. The ground slopes generally toward the south, and surface water that collects in perennial drainage ditches is directed to the east and north of the OBG area toward the Rutherford Fork of the Obion River several miles to the north.

The shallow geology beneath the OBG is composed of sediments indicative of the Memphis Sand "500"-foot aquifer that underlies MAAP. Geologically, the Memphis Sand consists primarily of a thick body of sand with discontinuous lenses of clay that constitute only a small percentage of the total thickness. In the subsurface, the sand is thick bedded, white to brown or gray, and very fine grained to gravelly. The upper portions of the Memphis Sand commonly contain fine sediments and soil borings advanced from zero to 10 feet below ground surface (bgs) are characterized by sandy silts and clayey sands. The depth to the water table in the vicinity of the OBG is approximately 80 feet bgs.

2.6.2 Nature and Extent of Contamination

Figure 2-2 illustrates the Conceptual Site Model (GSM) on which the risk assessment and response actions are based. The exposure pathways summary presented in the



CSM addresses potential exposures for site workers, hunters, farmers, potential future residents, and biota to explosives constituents.

Numerous investigations performed throughout the OBG between 1979 and 2008 identified explosives constituents and heavy metals in soil, groundwater, surface water (drainage ditches), and sediment samples. UXO and isolated areas of ACM were also identified within the four remediation areas and pose a health and safety worker concern during construction of the caps. Explosive compounds are likely present as a result of ordnance disposal, destruction, testing, and storage activities conducted within the MAAP OBG. Heavy metals are likely associated both with natural background conditions and with past ordnance disposal activities. UXO may be present as a result of past ordnance disposal activities, and potential ACM may be present from historical disposal of construction materials such as corrugated transite and ceiling plaster.

The main COCs being addressed by this remedy are the explosive compounds RDX and TNT. These explosives have been detected in on-site soils at concentrations that would potentially present an unacceptable risk should chronic residential exposure occur. In addition, the soils may potentially continue to serve as a source of groundwater contamination if no action is taken. ACM and UXO in the immediate vicinity are also being addressed by this remedy to ensure that the selected remedy (capping) can be implemented safely. The ACM observed on site is currently non-friable, but could become friable, and therefore hazardous, if mechanical equipment or vehicles are used at the site (i.e., during cap construction). As a result, ACM identified in the vicinity of the capped areas and/or work zones will be safely relocated to beneath a capped area. Finally, UXO avoidance (and clearance as needed) will be performed during fieldwork to protect remediation workers against the safety hazards associated with the potential UXO at OBG.

The 2001 PS characterized the soil contamination in the OBG as "scattered hot spots ...within a fairly broad area of low level contamination." The occurrence of sediment and surface water is sparse in this area and consists of media existing only in ephemeral drainage ditches; receiving waters did not exhibit elevated levels of COCs.

Supplemental field characterization efforts were performed in 2005 to refine the volumes of soil requiring remediation in the four areas identified in the 2001 PS. The findings of these efforts indicated that the majority of the RDX mass in the soils is present in the upper 2 feet of the ground surface and also indicated that RDX concentrations above 10 mg/kg were generally limited to depths less than 4 to 5 feet bgs.

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As presented in the 2010 FSA/SRI, the Selected Remedy will be applied to four areas within the OBG, collectively representing approximately 4.4 acres. Figure 2-3 illustrates the four areas of the OBG (referred to as OBG01, OBG02, OBG03, and OBG04) where the Selected Remedy will be implemented.

2.6.2.1 Development of COCs

The 2001 FS retained RDX as a COC based on modeling results for the soil leaching to groundwater migration pathway. Calculations were performed only for RDX, which was the constituent present in soil that was most likely to exceed drinking water goals based on its observed soil concentrations, mobility, and toxicity. Modeling results indicated that concentrations of RDX above 50 mg/kg were particularly significant sources of groundwater contamination that would continue to develop leachate, resulting in adverse groundwater impacts. Although the effects of elevated TNT in soil were not modeled, it was later added as a COC to be consistent with the OU3/OU4 ROD.

In the 2010 FSA/SRI, exposure pathways for potentially exposed populations were reevaluated and the residential exposure scenario was retained at the request of USEPA. Residential use of the site was initially evaluated in the Human Health and Environmental Risk Assessment presented in the 1999 Rl to provide a conservative estimate of potential risk but was omitted from the 2001 FS because it was determined not to be a realistic exposure scenario. The risks to hypothetical future residents presented in the 1999 Rl for ingestion of surface soil during yard work or gardening and as household dust could result in an estimated excess lifetime cancer risk of 3x10"'^ using reasonable maximum exposure (RME) parameters cited in the Rl.

The residential risks and hazards documented in the 1991 Rl were reviewed in 2010 during preparation of the FSA, and three metals (arsenic, cadmium, and manganese) were identified as residential COCs based on cumulative risks greater than 1 x 10'® or hazard quotients greater than 1.0. Table 2-1 summarizes the risks and hazards for COCs retained in the risk assessment for both explosives and metals. The table illustrates that RDX is the main risk driver for both cancer risks and toxic hazards. The metal with the highest risk is arsenic, with an Excess Lifetime Cancer Risk (ELCR) of 7E-5; the RDX ELCR was 4E-2 (three magnitudes greater). The metal with the highest hazard quotient (HQ) was cadmium, with a child HQ of 21; the RDX child HQ was 623 (almost 30 times greater).


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The hypothetical residential exposure of lead in children (the most sensitive potential residential receptor) was evaluated in the 1999 Rl using the USEPA's Integrated Exposure Uptake Biokinetic (lEUBK) model. The results of the lEUBK evaluation showed that the geometric mean blood lead concentration was predicted to be 6.5 micrograms per deciliter (pg/dL), which is less than the national health criteria of 10 pg/dL for no more than 5 percent of the population (USERA 2003). Since the estimated blood lead level was less than 10 ug/dL and the OBG/ADA was not expected to be used for residential purposes, lead was not identified as a COC.

In 2009, an evaluation of the location and concentrations of lead at the OBG was performed to address a USERA concern that there was a possibility of hotspots of lead. Since the 1991 Rl had addressed potential residential exposure to lead, the 2009 evaluation focused on potential industrial exposures.

USERA's Adult Lead Model (ALM) (USERA, 2003; 2009a) was used to evaluate the average lead concentrations from three possible hotspots (i.e., areas having the most elevated lead concentrations in shallow soil) against the USEPA (2009a) regional screening level (RSL) for exposure to soil under an industrial setting. The results of the modeling indicate that there is a probability greater than 95 percent that predicted blood lead concentrations will be less than the 10 microgram per deciliter (pg/dL) benchmark, indicating that it is unlikely that worker exposure to lead in the surface soil in hotspot areas would adversely affect the fetus of a female worker. These assessments concluded that lead was not a risk driver for the remedy and that no RG was required for lead.

Finally, the U.S. Army recognizes that munitions-related actions (in addition to the UXO clearance required for implementation of the Selected Remedy) may be needed beyond the four areas addressed in this ROD. These munitions-related areas will be addressed under the Military Munitions Response Program (MMRR) undera separate administrative process.

2.7 Current and Potential Future Land and Resource Uses

2.7.1 Current and Anticipated Future Land Use

MAAR is currently an active Army installation (or post). The installation currently leases land (outside of industrial areas) for agricultural purposes, including grazing cattle and growing crops. The installation also issues permits for hunting and fishing (in non-secured areas) to active duty and retired military personnel and civilian employees.

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MAAP Is housed on 22,420 acres with 1,450 buildings, 8/3 igloos, and a storage capacity of 2,270,000 square feet.

The overall OU5 area is largely undeveloped and is used primarily for storage of finished ordnance and general supplies (referred to as the ASA), as well as for short-term storage of hazardous wastes associated with the ammunition manufacturing processes (ICF, 1991). The storage areas are fenced and remote from the areas being addressed in this ROD. The OBG, in the northeastern portion of OU5, continues to be used as an area for flashing of explosives-related media and burning of packaging and articles that have been in contact with explosives.

Future uses of MAAP are anticipated to realign from LAP of munitions to operations focused on munitions storage. The LAP operations will be placed in stand-by mode for an unspecified period of time in case a future demand for these services develops. MAAP is not on the list for base closure, and there are no plans for closing the installation. The U.S. Army has no foreseeable plans to develop or use the non-industrial areas that surround the OBG for any industrial or residential purpose. The possibility exists to expand wildlife management within the installation and increase game populations for hunting. Since the surrounding area is predominantly rural and the demand for housing in the immediate vicinity of MAAP is not increasing, the least likely future use of the OBG and surrounding areas at MAAP is residential development.

2.7.2 Surrounding Land Use

The OBG area is completely surrounded by portions of the MAAP installation, and the nearest distance to the MAAP boundary is approximately 1 mile. The land surrounding MAAP is predominantly rural and consists mainly of undeveloped land with portions being used for agricultural and agricultural research purposes. Adjacent and to the west of MAAP is the City of Milan with adjoining properties being used primarily for commercial/industrial purposes.

2.7.3 Current Groundwater Use

Groundwater at MAAP is used for industrial, agricultural, and potable purposes. Groundwater affected by the OU5 site is contained within MAAP and is not expected to migrate to the facility boundary. Groundwater beneath OU5 will be addressed under a separate site-wide groundwater ROD. MAAP effectively manages the resource to ensure that groundwater is extracted only from portions of the aquifer that are


unaffected by sources of contamination, and monitors groundwater quality routinely to ensure the quality of extracted groundwater.

Both public and private wells are located off-post. The private wells supply low quantities of water for domestic or farm usage. Existing public supply wells are not anticipated to be impacted by any groundwater contamination associated with MAAP.

The anticipated future use of groundwater at MAAP and in the vicinity of MAAP is not expected to change based on the Army's current mission at the installation and overall land use control management plan.

2.8 Summary of Site Risks

The baseline risk assessment estimates the risks the site poses if no action were taken. It provides the basis for taking action and identifies the contaminants and exposure pathways that must be addressed by the remedial action. The PS (Harding ESE, 2001) presented a summary of the Human Risk Assessment (HRA) and the Ecological Risk Assessment (ERA), each performed as part of the Rl, and also evaluated the potential threats to groundwater from impacted soils. Data considered in the HRA and ERA were derived from sampling events performed at the OBG and at nearby areas (FADA, ATA, etc.) where site use was similar in nature. The PSA presented additional information concerning human health and ecological risks (ARCADIS, 2010a). The 2010 risk evaluation concluded that remedial action is required to protect against direct human exposure by potential future residents and to protect groundwater quality at the OBG. This section of the ROD summarizes the findings of the human and ecological risk assessments.

2.8.1 Potential Risks to Human Health

An analysis was conducted to estimate the current and future human health risks associated with exposures to residual soil/sediment and surface water contamination detected within OU5. Surface water contamination was evaluated because soil contamination was primarily found in ditches that convey surface runoff to streams during storms. Although the ditches are usually dry, contamination of soil/sediment in the ditch bed could contaminate the runoff and the streams to which they discharge. The results of this evaluation were used to determine if specific chemicals would require remedial action, and, if so, to prioritize areas requiring remedial action.


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The Human Risk Assessment summarized in the 2001 FS evaluated six different exposure scenarios (situations by which people might be exposed to the contamination). With respect to the OBG/FADA areas at OU5, the following groups were considered in the baseline risk assessment for potential risks to human health:

• Workers at the OBG/Current ADA and FADA (evaluated as a single receptor group and exposure area)

• Farmers

• Hunters

• Residents (hypothetical future use)

It should be noted that only the first of the above receptor groups (workers) is potentially exposed to the soil at the OBG currently. The next three receptor groups (farmers, hunters, residents) could be exposed to the soil at the OBG only if land use changes at the site. The potential exposure routes for the receptors at the OBG are summarized on Figure 2-2.

Risks were calculated for the various receptor groups in accordance with applicable USERA guidance and are summarized in Table 2-2. In accordance with USERA guidance, risk estimates tend to be conservative as a result of the use of conservatively defined exposure factors, exposure concentrations, and dose-response toxicity values. Based on the baseline risk assessment, the COCs for soil at OU5 are explosives constituents and metals. RDX and TNT contribute more than 95 percent of the estimated cancer risk and hazard indices (His) for all receptors and sub-areas of OU5. Table 2-2 provides a list of constituents evaluated in historical investigations and subsequently retained as chemicals of concern for soil or soil pathways (ingestion of garden produce grown in site soils) through risk assessment evaluations.

RDX and TNT are considered possible human carcinogens (USERA Category 0). Lead is a probable human carcinogen (USERA Category B2). Each of the COCs is also believed to cause adverse non-carcinogenic effects under low-level chronic exposure conditions. RDX is readily leachable from soils and is relatively persistent in groundwater. TNT exhibits similar mobility and persistence properties, although it is slightly less mobile and less toxic than RDX. Both constituents have contaminated groundwater downgradient of source areas within OU5. RDX is the more significant potential groundwater contaminant because of its greater mobility and toxicity.



Potential exposure routes include incidental ingestion and dermal contact with soils/sediments. Additionally, potential exposure to game (such as deer, quail, and rabbit) harvested from the area and subsequently ingested was also evaluated. As part of the exposure assessment, chemical intakes (the amount of chemical entering a receptor's body) were calculated for each metal and explosive via each exposure pathway (such as through eating, breathing, or touching each chemical) at each study area. Chemical intakes were calculated based on standard USERA exposure formulas and factors, which address the frequency and magnitude of exposure.

The risks from exposure to soil estimated for all of the potentially exposed populations (except residential) were estimated to be less than or within USEPA's acceptable range, which indicated that remedial action was not warranted to protect human health. Although residential use of the site is not realistic, risk calculations were performed for informational purposes to evaluate the need for land use restrictions or controls.

The cumulative excess cancer risk for all residential exposure pathways (direct exposure to soil, use of groundwater as a potable water source, surface water ingestion, direct exposure to sediments, and ingestion of produce grown in on-site soil) was 4x10'^ (i.e., 4 in 100). USEPA has established a target risk range of 1 excess cancer in a population of 1,000,000 (10'®) to 1 excess cancer in a population of 10,000 (10"'^) for evaluating the need to remediate a site. As shown in Table 2-1, the residential risk is primarily due to the ingestion of garden produce grown in on-site soils that contain RDX (4 x 10'^). The residential excess cancer risk as a result of the use of groundwater by residents was 2 x 10"'^, with the risk primarily due to the ingestion of groundwater containing RDX. The residential risks from exposure to both soil and groundwater were greater than the USEPA target risk range, thereby indicating that LUCs are needed to prevent residential development of the OBG area. The cumulative non-carcinogenic His for residential child and adult exposures were 720 and 195, respectively (ARCADIS, 2010a). The USEPA acceptable HI is 1.0 or lower, further suggesting that LUCs are needed to prevent residential development of the OBG area. As shown in Tables 2-4 and 2-5, the residential His are primarily due to the ingestion of produce grown in on-site soils that contain RDX (715 and 198 for residential child and adult exposures, respectively). The residential His for the use of groundwater and for exposure to soil were also greater than 1.0 and primarily due to RDX.

In addition, ACM and UXO are also being addressed by this remedy. The isolated areas of ACM observed on site are currently non-friable, but could become friable, and therefore hazardous, if mechanical equipment or vehicles are used at the site. The



ACM and UXO pose a threat of a significant safety hazard if intrusive activities occur at iccaticns where potential ACM or UXO is present.

2.8.2 Potential Risks to the Environment

For the ERA, four exposure areas were defined based on location and history of activities. These areas are the Probable Direct Impact Areas (OBG, Current ADA, FADA, ATA, and the Closed ABA); the ASA; and two reference areas, a Distant Area (pasture and woodland) and a Near Area (pasture and woodland). The ERA included surface water sampling, sediment sampling, surface soil sampling, fish tissue sampling, vegetation tissue sampling, mouse tissue sampling, vegetation surveys, mammalian surveys, avifauna (bird) surveys, and herpetofauna (amphibians and reptiles) surveys. A review of the survey information for MAAR indicates that populations of organisms are generally diverse, present in densities equivalent to expectations, and apparently healthy and reproducing. Calculations were performed comparing estimated wildlife exposure rates to exposure rates that are considered safe. The results of these comparisons are referred to as HQs. The HQ calculations performed for impacted and reference areas yielded similar results, indicating that explosives and metals do not present an ecological risk to sensitive receptors in the potentially impacted areas of MAAR.

2.8.3 Protection of Groundwater

Groundwater investigations performed in the OU5 area identified contaminant plumes likely originating from the OBG. Soil impacts at the OBG possess the potential to generate future groundwater contamination if not remediated. RDX is the dominant groundwater COC found in soils of the OBG, considering its concentrations in soil, mobility, and toxicity.

The effects of soil contamination leaching to groundwater were evaluated in the 2001 FS to estimate the effects of potential leachate on the groundwater quality at the downgradient (northern) edge of the OBG and FADA. Modeling results indicated that concentrations of RDX in soils could potentially affect groundwater quality. Leaving a potential continuing source of groundwater contamination in place without attempting to remediate it would conflict with the Tennessee Water Quality Act, 69-3-101 et seq, and general provisions of Tennessee's Ground Water Quality Criteria, 1200-4-3, as well as guidance published by USERA. Therefore, RDX was retained as a COC for consideration in the development of remedial alternatives. While the effects of elevated



TNT In soli were not modeled, this compound was later added as a COC to be consistent with soil cleanup efforts completed under the OU3/OU4 ROD.

2.8.4 Basis for Action

The response action selected in this Record of Decision is necessary to protect public health or welfare or the environment from actual or potential releases of hazardous substances into the environment that may potentially present an endangerment to public health or welfare.

2.9 Remedial Action Objectives

Remedial Action Objectives (RAOs) are general descriptions of what the remedial action is expected to accomplish and are designed to protect human health and the environment. In general, the RAOs for OU5 OBG soils are to prevent exposure to contaminated soils and protect the groundwater resource from further degradation.

As discussed in Section 2.8, the risks associated with direct soil contact at OU5 were estimated to be less than or within USEPA's acceptable risk range under current and reasonable future exposure scenarios (workers, farmers, and hunters). However, residential exposure to soils at the OBG may result in unacceptable risk. Therefore, remedial action is required to prevent residential land use or other soil exposures that may result in unacceptable risks.

The risk-based RGs for soil remediation at the OBG are as follows:

• RDX concentrations in soil above 10 mg/kg require remediation.

• TNT concentrations in soil above 25 mg/kg require remediation.

• Note: Friable ACM, if encountered at the ground surface, will be remediated by placing the ACM under a capped area.

To protect human health and groundwater resources and to maintain consistency with completed remedial actions for other soil operable units at MAAR (e.g., OU3/OU4), the following RAOs for impacted OBG soils were developed:

• Prevent potential future residents from direct contact with COCs in soil at concentrations above RGs

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• Prevent potential future residents from direct contact with surficiai ACM

• Limit or eliminate agitation of ACM during soil remediation activities to prevent potential non-friable ACM from becoming friable

• Stabilize soil in impacted areas to protect surface water resources

• Limit groundwater infiltration through soil containing RDX or TNT at concentrations above RGs to protect groundwater resources

• Establish and maintain LUCsto limit access to remediated areas and prevent disturbance to the remedy where COCs remain in place

2.10 Description of Remedial Alternatives

The reevaluation of remedial alternatives performed in the 2010 FSA resulted in retaining three of the original five alternatives presented in the 2001 FS (Alternatives A, B, and C). The remaining two alternatives (Alternatives D and E) that included excavation as a primary component were determined to be unimplementable because of health risks associated with comingled UXO and ACM. In addition, a new alternative (Alternative F) was added to respond directly to the increased health risks presented by comingled UXO and ACM.

Applicable or Relevant and Appropriate Requirements (ARARs) initially proposed in the 2001 FS were reevaluated during preparation of the 2010 FSA. A summary of ARARs presented in the FSA is provided in Section 2.13.2. The summary of comparative analysis presented later in this section describes how alternatives either meet, or fail to meet, ARARs.

2.10.1 Alternative A: No Action

Alternative A, No Action, was developed to provide a basis for comparing active treatment alternatives. The NCR and CERCLA, as amended by SARA, require the evaluation of this alternative as a baseline for comparison of risk reduction achieved by each treatment alternative. The No Action alternative does not involve any remedial actions. The toxicity, mobility, or volume of contaminants at the site would not be reduced. There would also be no additional considerations or changes to this alternative resulting from the potential presence of ACM.



Capital Cost: $0 Annual Operation and Maintenance (O&M) Cost: $0 Months to Implement: None

2.10.2 Alternative B: Limited Action

Alternative B, Limited Action, was developed to reduce the potential for public exposure to the contaminated media. The toxicity, mobility, or volume of contaminants would not be reduced. Such measures would include LUC restrictions, access restrictions, public education programs, possible long-term environmental monitoring, and five-year reviews. This alternative would consist of continued maintenance of the existing fences around the OBG area. These activities would be performed under a Memorandum of Agreement with USEPA Region IV and TDEC. There would be no additional considerations or changes to this alternative resulting from the potential presence of ACM.

Capital Cost: $119,794 Annual O&M Cost (Year One): $70,435 Total O&M Cost: $874,028 (30 year duration) Total Lifecycle Cost: $993,821 (30 year duration) Months to Implement: 4 to 8

2.10.3 Alternative C: Engineered Caps (original asphalt-based alternative) with LUCs

Containment of explosives-contaminated soil was one of the alternatives presented in the 2001 FS. With the containment option, the contaminated soil would be left in place and LUCs would be instituted to eliminate direct exposure to the contaminants in the soil and to protect groundwater quality. Containment measures such as an engineered cap would reduce direct exposure to the contaminated soil and protect the groundwater. In addition, constructing engineered caps over impacted soils with potential UXO and ACM provides increased safety to site workers during remedy implementation as compared with remedial approaches that require significant excavation (i.e., formerly considered Alternatives D and E).The engineered asphalt caps would be designed to meet relevant federal and state requirements, which require caps to have permeability less than or equal to the permeability of the natural subsoils at the site. The engineered caps would be inspected and maintained to ensure performance integrity, and LUCs would be implemented to prevent disturbance of the capped areas and limit the use of the areas. Five Year Reviews would be conducted to evaluate the effectiveness of the remedy.

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Engineered caps are proven remedies that decrease contaminant mobility and eliminate the possibility for direct human exposure to contaminated soil. While this remedy would not reduce the toxicity or volume of the contaminants, natural attenuation processes that reduce toxicity over time within the capped soils would continue to occur. Excavation of the asphalt capped areas would be restricted as a requirement of implementing the capping remedy to reduce risks to site workers. The final design of the capping remedy would be optimized in the field to lap the edges of cover material onto the existing topography and facilitate construction.

The 2001 FS considered capping via the use of a layer of asphalt over a liner-covered gravel base. Asphalt-based caps would decrease contaminant mobility and eliminate the possibility for human exposure to contaminated soil. Asphalt caps would, by design, not allow rainfall to percolate through impacted soil, thereby resulting in increased surface runoff and additional engineering design to control erosion. This would in turn lead to an increased level of excavation associated with stormwater collection system construction, which would increase safety hazards associated with handling UXO and ACM in the remediation zones.

Capital Cost: $3,851,138 Annual O&M Cost (Year One): $79,668 Total O&M Cost: $988,605 (30 year duration) Total Lifecycle Cost: $4,839,743 (30 year duration) Months to Implement: 12 to 18

2.10.4 Alternative F: Engineered Cap with GCL and Vegetative Cover with LUCs

Alternative F was developed to address revised remedial goals and objectives resulting from the discovery of comingled UXO and ACM at the OBG. This alternative is similar in nature to Alternative C in that contaminated soil would be capped and left in place and LUCs would be instituted to eliminate direct exposure to the contaminants in the soil and to protect groundwater quality. Instead of an asphalt-based construction, the caps would be GCL-based (geosynthetic clay layer) and would be designed to meet relevant federal and state requirements, which require caps to have permeability less than or equal to the permeability of the natural subsoils at the site.

This GCL-based construction would be consistent with remediation methods used in the completed remedial actions at OUs 3 and 4. The GCL of the engineered cap would be constructed below a protective layer of soil and an overlying vegetative layer would effectively limit rainfall percolation while establishing a natural surface layer that would



require little long-term maintenance. In addition, this design approach meets applicable state requirements for management of ACM at disposal sites and is protective of surface water via land stabilization.

The engineered caps would be inspected and maintained to ensure performance integrity, and LUCs would be implemented to prevent disturbance of the capped areas and limit the use of the areas. Five Year Reviews would be conducted to evaluate the effectiveness of the remedy.

Capital Cost: $2,013,157 Annual O&M Cost (Year One): $135,000 Total O&M Cost: $1,427,040 (30 year duration) Total Lifecycle Cost: $3,440,198 (30 year duration) Months to Implement: 12 to 18

2.11 Summary of Comparative Analysis of Alternatives

The objective of the analysis of remedial alternatives is to provide adequate information to facilitate the selection of remedial actions for implementation at the OBG. In order to implement the statutory provisions of CERCLA Section 121, and in accordance with the NCR (USEPA, 1990) and USEPA RI/FS guidance (USEPA, 1988; and 2000), each alternative was analyzed with respect to the nine criteria listed below.

1. Overall Protection of Human Health and the Environment

2. Compliance with ARARs

3. Long-Term Effectiveness and Permanence

4. Reduction of Toxicity, Mobility, or Volume Through Treatment

5. Short-Term Effectiveness

6. Implementability

7. Cost

8. State/Support Agency Acceptance



9. Community Acceptance

A summary of how each alternative either met, or failed to meet, the nine CEROLA criteria is provided in this section. The comparative analysis of alternatives was performed critericn-by-criterion, emphasizing the important tradeoffs among alternatives. Table 2-7 provides a qualitative comparison of how the alternatives comply with the requirements of CEROLA Section 121.

2.11.1 Overall Protection of Human Health and the Environment

Because current levels of contamination pose unacceptable risk levels to potential future residents. Alternative A, No Action, would not meet this criterion because no actions are taken to eliminate, reduce, or control exposure pathways. The threshold criterion of protection of human health and the environment would not be achieved by Alternative A. Alternative B, Limited Action with LUCs, prevents residential development of the OBG and associated exposure to contaminated soil by land use controls, but would do nothing to mitigate further degradation of the groundwater resource resulting from rainwater infiltration through impacted soils. Alternative B would, therefore, not provide long-term protectiveness of human health and the environment. Alternatives C and F would provide a barrier to rainwater infiltration, which would result in greatly reduced leaching of the contaminants and improved groundwater protection. Protection of human health and the environment would be accomplished; eliminating the surface soil exposure pathway and by providing protection against continued degradation of the groundwater resource. Long-term maintenance of the engineered caps would be required. A comparison of Alternatives A, B, C, and F against this criterion are included in Table 2-7.


Section 121 (d) of CERCLA, as amended, specifies, in part, that remedial actions for cleanup of hazardous substances must comply with requirements and standards under federal or more stringent state environmental laws and regulations that are applicable or relevant and appropriate (i.e., ARARs) to the hazardous substances or particular circumstances at a site or obtain a waiver. See also 40 CFR § 300.430(f)(1)(ii)(B). ARARs include only federal and state environmental or facility siting laws/regulations and do not include occupational safety or worker protection requirements. In addition to ARARs, the lead and support agencies may, as appropriate, identify other advisories, criteria, or guidance to be considered for a particular release. The "to-be-considered" (TBC) category consists of advisories, criteria, or guidance that were developed by



USEPA, other federal agencies, or states that may be useful in developing CERCLA remedies. See 40 CFR § 300.400(g)(3). Compliance with ARARs is a threshold criterion that must be met by the proposed remedial action, unless a waiver is justified.

There are no chemical-specific or location-specific ARARs applicable to remediation of OU5 OBG soils. Because no remedial activities would be implemented under Alternatives A and B, action-specific ARARs do not apply except to the extent that Alternative B does contain passive restrictions through enactment of LUCs. Alternatives 0 and F involve further actions to prevent contaminants in soil from migrating and adversely affecting the groundwater resource. Action-specific ARARs were identified in the 2010 FSA for those alternatives that are both implementable and can achieve the statutory requirements of CERCLA Section 121 (i.e.. Alternatives C and F). These ARARs include requirements and standards under federal or state environmental laws pertaining to general construction activities; waste generation, characterization, segregation, and storage of secondary wastes; in-place capping of wastes; post-closure care of capped wastes; institutional controls of capped wastes; and transportation of wastes. The remedial actions planned under the Selected Remedy will be performed in compliance with these action-specific ARARs. These ARARs provide protection to site workers and long-term protection of groundwater. Appropriate LUCs must also be placed on the property in compliance with ARARs to restrict disruption of subsurface ACM and prevent residential development of the OBG area. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7. CERCLA contains a permit exemption for all on-site remedial actions but substantive requirements of permits will be followed in accordance with Section 121(e).

2.11.3 Long-Term Effectiveness and Permanence

Alternatives A and B would not provide long-term effectiveness and permanence. Neither of these alternatives would reduce the risk posed to hypothetical future residents nor would they provide protection of groundwater above risk-based levels.

Alternatives C and F would provide long-term isolation of explosives-contaminated soil and ACM and, if properly maintained, would limit contaminant leaching to groundwater. Human exposures to surface soil via direct contact and incidental ingestion would be eliminated and groundwater would be protected. Stormwater runoff would be decreased by infiltration and the uptake of rainwater by vegetation in Alternative F as compared with increased runoff associated with the asphalt-paved surface of Alternative C. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7.


2.11.4 Reduction ofToxicity, Mobility, or Volume Through Treatment

Alternatives A and B would not provide any reduction of toxicity, mobility, or volume of the contaminants because removal or treatment of the contaminated soil is not a component of these alternatives. Alternative C and F would not satisfy the statutory preference for treatment as a remedial method since the soil that is presently contaminated with both explosives (i.e., munitions constituents or "MC") and ACM would remain on site under this alternative at levels unchanged except for intrinsic biodegradation of MC. However, mobility of MC into the groundwater, as well as dispersion of MC or surficial ACM by wind and water runoff, is significantly reduced, if not prevented, under Alternatives C and F in contrast to Alternatives A and B. The mobility of both MC and ACM would be decreased substantially in Alternatives C and F by the caps in two basic ways. The caps associated with either Alternative C or F would decrease or eliminate rainwater infiltration through impacted media and effectively limit the downward migration of MC in the soil column, providing adequate protection to groundwater. Further, the cap and associated LUCs designed to maintain its performance integrity would also enhance the management of erosion in areas potentially containing MC or ACM, thereby preventing surface water from becoming impacted as compared with Alternatives A and B. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7.

2.11.5 Short-Term Effectiveness

The No Action and Limited Action alternatives could be implemented immediately. The No Action alternative does not require services, materials, or labor. The objectives of the Limited Action alternative can be immediately implemented. This alternative requires minimal materials and labor for public education and monitoring. All components necessary for the Limited Action alternative are immediately available. Alternatives C and F would each provide for short-term protection of the public, workers, and the environment during implementation. The use of proper engineering and safety controls to limit risks associated with handling comingled MC, UXO, and ACM would be difficult, but manageable. Dust suppressant measures would control windblown emissions of contaminated dust to protect community and on-site workers. Proper personal protective equipment would be required for site workers. Alternatives C and F would require three to nine months to design and up to nine months to construct. Construction of GCL-based caps would require approximately half of the fieldwork time of asphalt caps because of reduced site preparation requirements. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7.


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2.11.6 impiementabiiity

Alternatives A and B would be the easiest alternatives to implement. Alternative A would require no change in existing controls and most of the components of Alternative B are already in place. Alternative C, consisting of covering the explosives-contaminated surface soil with the engineered caps, would be relatively easy to implement. Appropriate materials (gravel) could be readily obtained from local sources. Other materials, such as synthetic liners and asphalt, are commercially available. All required equipment for earthwork and asphalt paving is also commonly available. Additional actions, such as repairs to the asphalt, would be relatively simple to implement. Compared with Alternative F, this alternative would require significant grading and earthwork in order to properly install the asphalt paving, potentially increasing disturbances below grade. In addition, asphalt caps would increase surface runoff from the capped areas, resulting in the need to construct stormwater management features that would be far more complex than those needed for the GOL-based caps proposed under Alternative F. Periodic monitoring and maintenance would include visual inspection of the individual engineered caps to ensure they are still intact. Alternative F would require slightly more engineering support along with the need for some more specialized equipment and raw materials as compared with Alternative 0. Alternatively, placing GOL materials is well understood and is implemented widely at landfills in the region. Once natural vegetation is established on the Alternative F cap, upkeep and maintenance would be significantly less than maintenance of the asphalt cap in Alternative C. Periodic monitoring and maintenance would include visual inspection of the caps and repairs to any erosion to maintain structural integrity. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7.

2.11.7 Cost

There is no cost under Alternative A. Alternative B would be the least expensive alternative, with estimated capital costs of $119,794 and O&M costs of $874,028. Alternative C is the most costly alternative considered with estimated capital costs of $3,851,138, O&M costs of $988,605, and total lifecycle costs of approximately $4.8 million. Repair of pavement over the lifecycle of the asphalt surface of Alternative C is inevitable, and weathering will cause potential breaches in the impermeability of the cap over time. Alternative F, with estimated capital costs of $2,013,157, O&M costs of $1,427,040 and estimated total lifecycle costs of $3.4 million, is less expensive to implement and has a lower overall cost than Alternative 0. The caps associated with Alternative F would be expected to naturally re-vegetate following seasonal changes.



resulting in minimal cost impact. Annual O&M costs for Alternative F would be slightly higher than Alternative C. A comparison of Alternatives A, B, C, and F against this criterion is included in Table 2-7.

2.11.8 State Acceptance

TDEC has actively participated in the development and evaluation of alternatives during the preparation of the FSA and agrees that Alternative F should be the Selected Remedy. TDEC agrees that Alternative F provides the best balance of protection, implementability, cost-effectiveness, short-term protection during implementation, and long-term benefit.

2.11.9 Community Acceptance

The community has been informed of investigative findings and discussions of potential remedial plans for the OBG during numerous RAB meetings held over the past five years. In addition, a notification was published in local newspapers on April 27, 2010 informing the public of the availability of the Final FSA and Draft Final Proposed Plan in the information repositories located at MAAP and the Milan Public Library. Interested citizens are able to review these and other OBG documents to gain more information on remediation plans. A public meeting was held at the Milan Seniors Center, 1075B East Van Hook, Milan, TN 38358 on May 6, 2010 to discuss the Preferred Alternative identified in the Proposed Plan and other alternatives considered in the FSA. While some questions were verbally addressed at the public meeting, no written public comments have been received. Community acceptance of Alternative F as the Selected Remedy is therefore assumed and is addressed further in the Section 3, Responsiveness Summary.

2.12 Selected Remedy

2.12.1 Summary of Rationale for Selected Remedy

Alternative F as described in the FSA and identified in the Proposed Plan as the Preferred Alternative, Containment - Engineered Cap with GCL and Vegetative Cover with LUCs, is the Selected Remedy. This remedy was selected because it will achieve substantial risk reduction both by reducing the potential threat of direct contact to site workers and hypothetical future residents and by providing safe management of remaining materials. It also greatly reduces infiltration of rainfall through impacted soils, resulting in protection of groundwater resources. This remedy meets the statutory



requirements of CERCLA, is protective of human health and the environment, and complies with ARARs.

2.12.2 Description of the Selected Remedy

2.12.2.1 Engineered Caps

Engineered GCL-based caps will be constructed in several areas comprising a total of approximately 4.4 acres, depending on the buffer zone sampling results, as identified in the 2010 Final PSA. The volume of soil contained in this remedy ranges from approximately 7,700 cubic yards to 28,000 cubic yards based on a 4-foot average depth of RDX-impacted soil across the capped areas. A cross section of a typical cap is provided on Figure 2-4. Soil that exceeds RDX and TNT RGs as well as any visible ACM encountered during construction will be covered under the engineered cap. Visual ACM identified within one of the four targeted remedial areas but located beyond areas that exceed RDX or TNT RGs will be manually relocated to a capped area.

Soil sampling will be implemented during preconstruction phases of the remedy to refine the extent of RDX and TNT above action criteria in order to further refine the footprint of the cap. In addition, observations of surficial ACM will be performed during remedy construction to confirm that ACM present at the surface is addressed and placed beneath the cap(s).

Initial steps in the remedy implementation process will generally include the following:

• Collecting additional soil samples to further refine the design limits of the cap

• Performing a UXO avoidance sweep of the four cap areas followed by clearance of UXO items (if required) that may restrict the ability to place a base course of fill material

• Visually inspecting the revised limits of the cap and scouting the surrounding area for ACM at the ground surface

• Removing any ACM identified in proximity to the newly defined cap boundary and manually moving any identified ACM beyond this boundary to a central location within the cap area



UXO clearance/avoidance, soli sampling, and ACM surveys/recovery/confirmation sampling will be completed prior to mobilization of equipment and manpower to the site for cap construction to avoid unnecessary delays in the construction schedule. Design details will be developed as part of the Remedial Action Work Plan (RAWP). UXO technicians and safety support personnel will be available as needed throughout the OBG construction program to support field activities.

Construction activities will occur generally as follows:

• Silt fencing and/or hay bales will be installed with minimally invasive procedures using UXO avoidance measures to contain any runoff from the site during construction and post-construction monitoring. The silt fencing and/or hay bales will be maintained until vegetative cover is sufficiently established to warrant its removal.

• Each cap will consist of a base layer of compacted, clean fill constructed to a typical finished thickness of 2 feet. This material will be compacted to an appropriate dry density and will be free of sharp objects.

• The subgrade material will be sloped for positive drainage and to achieve a smooth transition back to existing ground elevation for all portions of the cap.

• Anchor trenches and related structural elements of the GCL layer will be constructed following completion of subgrade preparation. The anchor trench for the GCL will be constructed into the newly placed fill over the contaminated area and will be designed to not penetrate below existing grade. The GCL anticipated in the cap is a factory-manufactured hydraulic barrier consisting of sodium bentonite clay or other very low-permeability material between layers of geotextiles and/or geomembranes (i.e., similar specifications to GCL used at OU3/4 with a typical maximum permeability of 10'^ centimeters per second).

• Clean, compacted, granular material will be placed over the GCL to provide a drainage layer on top of the liner. This drainage course will be compacted to an appropriate dry density and will be free of sharp objects.

• The final layer of the cap will be comprised of topsoil that promotes growth of natural and introduced vegetation. Upon reaching final grade, each cap will be hydro-seeded similarly to caps constructed under OU3/4.



This ROD supersedes the 2004 IRGD and the 2007 ESQ previously issued for OU5 OBG soils and represents a change to a previously selected remedy as described in Section 2.5.

2.12.2.2 Land Use Controls

LUCs include institutional controls such as legal or administrative mechanisms that restrict the use of, or limit access to, contaminated real property to prevent or reduce risks to human health and the environment by minimizing the potential for exposure to contamination. LUCs can also include providing notice and information to governmental entities, property owners, and other interested parties about the LUCs and use restrictions required for the property. Additionally, LUCs can include physical controls such as engineered barriers or fences and signage to prevent unauthorized access to contaminated areas (e.g., RDX and TNT contaminated soils beneath engineered caps). As part of the selected remedy for the OU5 OBG site, LUCs will be implemented and maintained until the concentrations of hazardous substances in soil are determined to be at such levels as to allow for unrestricted use and unlimited exposure.

The Army is responsible for implementing, maintaining, monitoring, reporting on, and enforcing the LUCs for the duration of the remedy. Although the Army may later transfer these procedural responsibilities to another party by contract, property transfer agreement, or through other means, the Army shall retain the ultimate responsibility for the remedy integrity. The Army or any subsequent owners/lessors shall not modify, delete, or terminate any LUC without EPA and TDEC approval.

Placards (i.e., signage) prohibiting disturbance of capped areas will be installed. The LUC implementation actions, including signage, monitoring and enforcement requirements, will be provided in a LUC Implementation Plan (LUCIP) that will be prepared by the Army after the Record of Decision has been finalized. Within 90 days of ROD signature, the Army will submit to the USEPAfor review and approval a LUCIP, as part of the remedial design, that will contain implementation and maintenance actions, including periodic inspections. An illustration of the LUC boundary proposed for Selected Remedy is provided in Figure 2-5.

LUCs will be maintained until the concentrations of hazardous constituents in soil are at such levels to allow unrestricted use and unlimited exposure to OBG area soil. If soil conditions at the site improve, land use objectives change and remedial goals are met, then the Army, EPA, and TDEC may agree to evaluate whether to modify or



discontinue one or more LUCs. The Army will submit the LUCiP to USEPA and TDEC for review and approval pursuant to the Primary Document review procedures stipulated in the FFA. The Army will maintain, monitor (including conducting periodic inspections), and enforce the LUCs according to the requirements in the LUCIP and the ROD.

The LUC objectives for OU5 based on the remedial action objectives are as follows:

1. Prohibit residential, recreational or agricultural use of the OU5 OBG including capped areas. Prohibited residential uses shall include, but are not limited to, any form of housing, childcare facilities, pre-schools, elementary schools, secondary schools, play grounds, convalescent, or nursing care facilities.

2. Prevent unauthorized disturbance (e.g., digging, excavation/construction, drilling) of contaminated soil areas covered with engineered caps

3. Maintain the integrity of any current remedial (i.e., caps) and monitoring system

The following generally describes the LUCs that will be implemented at OU5 OBG to achieve the aforementioned LUC objectives:

• Incorporating the LUC boundary and land use restrictions for OU5 OBG into the installation's Land Use Control Plan (and any other relevant documents governing land use at MAAP).

• Utilizing the Facility Dig Restrictions process to require review/approval and implementation of worker protection practices before any intrusive activities are performed at the Site.

• Posting signs adjacent to caps advising that any excavation activity must be authorized in advance by the responsible environmental department. The size, location, and content of the signs will be specified in the LUCIP.

• A Notice of Asbestos Disposal as specified in TDEC 1200-3-11 -.02(2)(l)(5) will be recorded in the County Register of Deeds.

• Maintaining LUCs boundary with signage, existing OBG access gate, and existing site restrictions and conducting routine inspections in accordance with the LUCIP



to prevent unauthorized access, in the event any portion of OU5 OBG is transferred, additional security measures will be applied as needed.

• in the event any portion of OU5 OBG is transferred, the requirements of Tennessee Code Annotated (TCA) §-68-212-225 will be followed.

2.12.3 Performance Monitoring Strategy

The engineered caps will be inspected and maintained to ensure performance integrity, and LUCs will be implemented to prevent disturbance of the capped areas and limit the use of the areas for waste disposal. Cap inspections will initially be conducted quarterly and LUC inspections will be conducted annually in accordance with an approved LUCIP and the site-wide MAAP land use controls program. Inspection results and any required corrective actions will be documented on inspection logs and reports will be submitted to USEPA and TDEC following completion of each inspection. Based on the results of the inspections, the inspection frequency may be reduced upon concurrence from USEPA and TDEC. The inspection reports will be used in preparation of the Five Year Review to evaluate the effectiveness of the remedy. Additional long-term monitoring and maintenance details will be included in the Final RAWP and the Final RACR.

2.12.4 Summary of Estimated Remedy Costs

Cost information is based on direct construction costs and present worth analysis of long-term operation and maintenance costs. Complete remedy costs for Alternative F are estimated to be $3,440,198.

Total capital costs for remedial construction under this alternative are estimated at $2,013,157. Capital costs associated with preconstruction activities include engineering design, remedial action work plan development, procurement of materials and services, supplemental soil sampling, site preparation, and surveying. Capital costs associated with construction of the caps include construction materials and labor such as field engineering support, UXC-related support, health and safety support, and quality control testing.

The long-term maintenance and management costs over a 30-year period following construction completion are estimated to be $1,427,040. Costs associated with monitoring and maintenance of the caps include activities such as maintenance of LUCs, cap inspections, cap maintenance, preparation of inspection reports, and



preparation of five-year review documents. Actual costs associated with monitoring and maintenance may exceed this estimate if the monitoring period exceeds 30 years.

A cost estimate summary for the Selected Remedy is presented in Table 2-8.

2.12.5 Expected Outcome of the Selected Remedy

The Selected Remedy will be implemented to address impacted soil in the OBG portion of OU5 where RDX concentrations are greater than 10 mg/kg and TNT concentrations exceed 25 mg/kg, ultimately reducing risk to human health and the environment. These Remedial Goals were agreed upon by members of the U.S. Army, USERA, and TDEC. The estimated duration to achieve remedy implementation is 18 months. There are no changes for future land use under this Selected Remedy. Implementation of LUCs will restrict land use from transfer and development for residential use. In addition, the effectiveness of the capping remedy will be evaluated during five-year reviews.


The U.S. Army has, in conformance with CERCLA §121 and the NCR, determined that the Selected Remedy will be protective of human health and the environment, comply with applicable or relevant and appropriate requirements (unless a statutory waiver is justified), be cost-effective, and utilize permanent solutions and alternative treatment technologies to the maximum extent practicable. The following sections discuss how the Selected Remedy meets these statutory requirements.

2.13.1 Protection of Human Health and the Environment

The Selected Remedy will protect human health and the environment through the remediation of soil in the OBG that contains explosive compounds that exceed risk-based soil RGs (i.e., 10 mg/kg RDX and 25 mg/kg TNT). Capping of contaminated soils and maintenance of LUCs will eliminate the threat of exposure via direct contact or ingestion of contaminated soils and will minimize the potential leaching of explosive compounds from soil to groundwater. The selected remedy will reduce cancer risks from exposure to 10'®, which is within USERA's target risk range of 10"'^to 10'®. The HI for non-carcinogens will be reduced to less than 1.0. There are no short-term threats associated with the Selected Remedy that cannot be readily controlled. In addition, no adverse cross-media impacts are expected from the Selected Remedy. Rrotectiveness of this remedy will be enhanced by establishing



LUCs to prohibit disruption of the capped areas and eliminate the potential for residential development at the OBG in the future. LUCs will be maintained and protectiveness of the remedy will be reevaluated during the five-year review process.


Section 121 (d) of CEROLA, as amended, specifies, in part, that remedial actions for cleanup of hazardous substances must comply with requirements and standards under federal or more stringent state environmental laws and regulations that are applicable or relevant and appropriate (i.e., ARARs) to the hazardous substances or particular circumstances at a site or obtain a waiver. See also 40 CFR § 300.430(f)(1)(ii)(B). ARARs include only federal and state environmental or facility siting laws/regulations and do not include occupational safety or worker protection requirements. Compliance with OSHA standards is required by 40 CFR § 300.150 and therefore the CERCLA requirement for compliance with or wavier of ARARs does not apply to OSHA standards. Per 40 CFR § 300.400(g)(5), only those state standards are promulgated, are identified in a timely manner, and that are more stringent than federal requirements may be applicable or relevant and appropriate.

For purposes of ease of identification, the EPA has created three categories of ARARs: Chemical", Location- and Action-Specific. Under 40 CFR § 300.400(g)(5), the lead and support agencies shall identify their specific ARARs for a particular site and notify each other in a timely manner as described in 40 CFR § 300.515(d). Chemical-, and Location-Specific ARARs should be identified as early as the scoping phase of the Remedial Investigation, while Action-Specific ARARs are identified as part of the Feasibility Study for each remedial alternative. See 40 CFR §§ 300.430(b)(9) & 300.430(d)(3). Action-specific ARARs are usually technology-based or activity-based requirements or limitations that control actions taken at hazardous waste sites. Action-Specific requirements often include performance, design and controls, or restrictions on particular kinds of activities related to management of hazardous substances. Action-specific ARARs are triggered by the types of remedial activities and types of wastes that are generated, stored, treated, disposed, emitted, discharged, or otherwise managed.

Chemical-Specific or Location-Specific ARARs do not apply to the Selected Remedy. The Selected Remedy of capping contaminated soils and maintaining LUCs complies with the identified Action-Specific ARARs or to be considered (TBC) criteria. ARARs and TBCs that pertain to the Selected Remedy include Action-Specific requirements and standards under federal or state environmental laws pertaining to:



• General construction activities and cap installation (fugitive dust control and stormwater runoff control): TDEC 1200-3-8-.01, TDEC 1200-4-10-.03(2), TCA 69-3-108(j), General Permit No. TNR10-0000, Section 4.3.2

• Waste generation, characterization, segregation, and storage of secondary wastes (e.g., contaminated personal protective equipment or other equipment): 40 CFR 262.11, 40 CFR 262.34, 40 CFR 264.13(a)(1), 40 CFR 264.175, 40 CFR 265.171, 40 CFR 265.172, 40 CFR 265.173, 40 CFR 268.7(a), 40 CFR 268.9(a) TDEC 1200-1-11-.03, TDEC 1200-1-11-.06(2)(d)(1), TDEC 1200-1-11-.10(1), TDEC 1200-1-11-.03(4)(e), TDEC 1200-1-11-.05(9), TDEC 1200-1-11-.06(9)

• In-place capping of wastes (inactive asbestos waste disposal, landfill closure performance standards, landfill cover design and construction, landfill run-on and runoff control systems): TDEC 1200-3-11-.02(2), TDEC 1200-1-7-.04(8)

• Post-closure care and institutional controls of capped wastes (post-closure care for closed landfill, deed notice for asbestos waste disposal site, post-closure notices): TDEC 1200-1-7-.04(8), TDEC 1200-3-11-.02(2)(l)(5)

• Transportation of wastes (transportation of hazardous materials or transportation of waste off site): 49 CFR 171.1(c), 40 CFR 262.10(h), TDEC 1200-1-11-.03(1)(a)(8)

Table 2-9 provides a detailed list of ARARs and TBCs developed for the Selected Remedy.

Under CERCLA Section 121(e)(1), federal, state, or local permits are not required for the portion of any removal or remedial action conducted entirely on-site as defined in 40 CFR § 300.5. See also 40 CFR §§ 300.400(e)(1) & (2). Also, CERCLA actions must only comply with the "substantive requirements," not the administrative requirements of a regulation. Administrative requirements include permit applications, reporting, record keeping, and consultation with administrative bodies. Although consultation with state and federal agencies responsible for issuing permits is not required, it is recommended for determining compliance with certain requirements such as those typically identified as Location-Specific ARARs.

2.13.3 Cost-Effectiveness

The Selected Remedy is cost-effective because it is the least expensive of the alternatives considered in the FSA that is both protective of human health and the



environment and meets ARARs. This remedy represents a reasonable value for the money to be spent and costs are proportional to its overall effectiveness. By implementing the engineered cap with GCL and vegetative cover and LUCs, the Selected Remedy represents the best cost/benefit ratio, being less costly than the asphalt cap alternative, while providing equal protection of human health and the environment.

2.13.4 Utilization of Permanent Solutions and Alternate Treatment Technology

The Selected Remedy represents the maximum extent to which permanent solutions and treatment technologies can be utilized while maintaining a work environment that is safe for remediation workers. Treatment technologies that include excavation, mechanical separation of soil and UXO, or detonation in place of UXO items as a component of the remedy may have greater permanence or greater utilization of alternate technologies; however, these alternatives were determined to be unimplementable because of the risks associated with comingled UXO and ACM. With proper monitoring and maintenance, the Selected Remedy will provide safe, long-term effectiveness.

2.13.5 Preference for Treatment as a Principal Element

The Selected Remedy does not satisfy the statutory preference for remedies that employ treatment as a principal element because of the inability to safely handle media containing comingled UXO and ACM. Treatment technologies that include excavation or mechanical separation of soil and UXO, or possess the potential for unintentional detonation of UXO items where ACM is present, are unimplementable because of the increased health risks to site workers. As a result, the principal element of the Selected Remedy is containment.

2.13.6 Wastes Remaining on Site

Excess lifetime cancer risks and His reported in the 1999 Rl and reevaluated in the 2010 PSA indicate that unacceptable levels of risk to hypothetical future residents would occur from exposure to RDX in soil at the OBG; primarily through ingestion of garden produce. RDX is known to leach from soil to groundwater and then become mobile creating the dissolved RDX groundwater plumes observed at MAAP. RDX in soil at concentrations observed at the OBG may therefore be considered both highly toxic and mobile. However, the source material (i.e., RDX-impacted soil) being remediated under the Selected Remedy is not considered to be highly toxic to present



or reasonably possible future site workers, nor is the soil considered to be mobile. Therefore, RDX-impacted soil at the OBG is not considered to meet the definition of a principal threat waste and is considered to be a low level threat waste for all exposure scenarios except the hypothetical future resident. The Selected Remedy utilizes containment supported by LUCs to address wastes remaining at the site which provides protection to current and potential future workers and residents.

2.13.7 Five-Year Review Requirements

The Army will review the final remedial action no less than every five years after initiation of the remedial action in accordance with CERCLA Section 121(c) and the NCR at 40 CFR 300.430(f)(4)(ii) since hazardous substances, pollutants, or contaminants will remain at the site above levels that allow for unlimited exposure and unrestricted use. Additional remedial actions will be evaluated by the FFA parties and implemented if results of the five-year reviews reveal that remedy integrity is compromised, resulting in insufficient protection of human health and the environment.

2.13.8 Documentation of Significant Changes

CERCLA Section 117(b) requires an explanation of significant changes from the selected remedy presented in the Proposed Plan that was published for public comment. The Proposed Plan for the OU5 OBG Soil, Milan Army Ammunition Plant, was released for public comment on April 27, 2010. The Proposed Plan identified Alternative F: Containment - Engineered Cap with GCL and Vegetative Cover with LUCs, as the Preferred Alternative. The Army, USEPA, and TDEC reviewed and considered all comments received during the public meeting and the public comment period. The Army determined that no significant changes to the remedy were needed in response to public comments. The final Proposed Plan was added to the information repository in October 2010.

3. Responsiveness Summary

This section summarizes stakeholder concerns raised during the public comment period.

3.1.1 Stakeholder Issues and Lead Agency Responses

A public meeting was held on May 6, 2010 to discuss the remedial alternatives considered for the OBG and the findings of the FSA. The Preferred Alternative,



Alternative F, was also presented in detail at the meeting. Discussions included a review of each alternative considered, a comparative analysis of all alternatives, a summary of the benefits and drawbacks of remedial options, and a summary of how the Preferred Alternative complies with requirements outlined in CERCLA §121 and the NCR. Only general comments were raised during the meeting regarding the schedule for construction and cost of the remedy. The public comment period closed on May 28, 2010, and no written or oral comments were received during the comment period.

3.1.2 Technical and Legal Issues

No technical or legal issues have been raised or were encountered during the preparation of this ROD.

3.1.3 Summary of Comments and Responses

No written or oral comments were received by the U.S. Army or USERA during the comment period. The summary transcript of comments and responses from the public meeting is available in the information repository. No substantive comments were made in the meeting that required the Selected Remedy to be altered in any way.

4. References

ARCADIS 2004. Final Site-Wide Soils Characterization Work Plan; Guaranteed Fixed Price Remediation Performance Based Contract, Milan Army Ammunition Plant, Milan, Tennessee. October 2004.

ARCADIS 2006. Conceptual Site Model Report; Guaranteed Fixed Price Remediation Performance Based Contract, Milan Army Ammunition Plant, Milan, Tennessee. March 2006.

ARCADIS 2010a. Final Feasibility Study Addendum and Supplemental Remedial Investigation Report, Operable Unit 5 (Soils), Milan Army Ammunition Plant, Milan, Tennessee. March 2010.

ARCADIS 2010b. Final Proposed Plan, Operable Unit 5 - Open Burning Ground Soils, Milan Army Ammunition Plan, Milan, Tennessee. October 2010.

Fluor Daniel, Inc. 1999. Final Remedial Investigation, CU5, Southern Study Area Soils, Milan Army Ammunition Plant. Prepared for USAEC.



Harding ESE, inc. 2001. Final Feasibility Study for Operable Unit 5, Southern Study Area. Prepared for USAGE, Mobile District.

IGF Kaiser Engineers, Inc. 1991. Remedial Investigation for Milan Army Ammunition Plant. Prepared for U.S. Army Environmental Center, Aberdeen Proving Ground, Maryland. December 1991.

Post, Buckley, Schuh and Jernigan, Inc. 1988. Final Report Investigation and Engineering Analysis for Remedial Actions at the Milan Army Ammunition Plant Open Burning Grounds. Prepared for USAGE.

USEPA. 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA, Interim Final. October 1988.

USEPA. 1990. National Gil and Hazardous Substances Pollution Contingency Plan. March 1990.

USEPA. 2000. A Guide to Developing and Documenting Cost Estimates During the Feasibility Study. July 2000.

USEPA. 2003. Recommendations of the Technical Review Workshop for Lead for an Approach to Assessing Risks Associated with Adult Exposures to Lead in Soil, EPA-540-R-03-001, GSWER Directive 9285.7-54. December 2003.

USEPA. 2009. Update of the Adult Lead Methodology's Default Baseline Blood Lead Concentration and Geometric Standard Deviation Parameters, GSWER 9200.2-82. June 2009.


TZIX

f r

f l'^4

I®

0U1

Open Burning Ground

j<r

%

foil

0U5

/

1.5 MILES

GRAPHIC SCALE

LEGEND

i MAAR Property Boundary I Milan City Limits Roads OU1 Operable Unit OU2 Operable Unit OU3 Operable Unit OU4 Operable Unit OU5 Operable Unit

MILAN ARMY AMMUNITION PLANT MILAN, TENNESSEE

RECORD OF DECISION OPERABLE UNIT 5, OPEN BURNING GROUND SOILS

Site Location Map

fSl ARCADIS FIGURE

1-1

Si, z o < O s en o; m UJ 3 Q Q ^ o § o d ̂

ZJ ^ ^ 1

CL « o

z , UJ U) 18 §5

la 0£L

LEGEND

Ground Boundary

, Former Ammunition Destruction Area (ADA) Boundary

• ARCADIS Soil Sample Location

• Historical Soil Sample Location

0 600 1,200 ^ FEET

GRAPHIC SCALE



Site Map

fSl ARCADIS FIGURE

2-1

CfTYlKNX DIV/GROUP: ENV DB: B^LTOM PM: T.TALELE APM: D.WiLDERMAN TM: H.ENGLISH PROJECT; GP1MILAN.I005. ICGA1 PATH: G:\GIS\Milan\MapDocumenls\2010\OU5ROD_OBG_CSM.mxd SAVED: 12MAY2010

PRIMARY SOURCES

PRIMARY RELEASE

MECHANISM

SECONDARY SOURCES

SECONDARY RELEASE

MECHANISM

PATHWAY/ EXPOSURE

MEDIUM

RECEPTORS Human Biota

o i_

io

B c 3 X

c 0) •g "w <V

(Q 3

EXPOSURE ROUTE

Ammunition Destruction and

Burning Activities

Burial/Spills/ Leaks/

Leaching Soil

Dermal • • • •

Dust and/or Particulate Emissions

Plant Uptake

Wind Inhalation

Crops/ Wildlife

Ingestion

Infiltration/ Ground\Aater Ingestion • • Percolation Ground\Aater

Dermal •

Storm Water Runoff

Surface Water and Sediments

Ingestion • • • Dermal 1 • • •



Risk Assessment Conceptual Site Model

^ ARCADIS FIGURE

2-2

OBpOIGPOO?'

-V :4

€

OBG01 • OBG01GP021

1#^ •' • M OBe04GP02^^^ ODf^H/l , X iL VJDVJJU4

0BG04GP00S^io'<^-*^

OBG04GP009-, /

OBG01CAP501

OBG04CAP500

CC !" UJ ^ o Q

< i

•:. . M * I. ?

V \

iL^ - OBG02CAP501

:3480R230 * >

f

OSBGB-4 J

OBG03

-. -t^ • *'

LEGEND

Asbestos Detected Location

Sample Location (RDX Concentration >10 ppm)

Sample Location (TNT Concentration >25 ppm)

Asbestos Containing Materials (ACM) observed during April 2008 Site Survey (ARCADIS)

Proposed Multi-Aliquot Confirmation Sample

Anticipated Extent of Capped Area (>10 ppm RDX or >25 ppm TNT)

^ Confirmation Area for Refining Cap Footprint

NOTES: 1. Actual extent of cap will be based on confirmation results

during remedial design and buffer zone requirements. 2. ACM identified outside the capped areas will be manually

relocated to a location within the capped area.

300 600 ^ Feet

GRAPHIC SCALE



Conceptual Layout of Remedial Actions

ARCADIS FIGURE

2-3

CfTYlKNX DIV/GROUP: ENV DB: B^LTOM PM: T.TALELE APM: D.WILDERMAN TM: H.ENGLISH PROJECT; GP1MILAN.I005. ICGA1 PATH: G:\GIS\Milan\MapDocumenls\2010\OU5ROD_OBG_GCL.mxd SAVED: 13MAY2010

' * * * S

s •

Rainwater cannot penetrate the cap

^ m m m m «

S 4 ^ ^ • 4 4

^j^Geosvnthetic clay layer^^ prevents percolation

Clean Fill Dirt

Proper grading controls erosion

Water percolates through j

clean soil ^ No percolation beneath cap

Groundwater Flow

NOT TO SCALE



Conceptual Cap Design

ARCADIS FIGURE

2-4

5 o < cc ^ LO CC ID LU O Q . ^ ' 5 S

^ E u 3

t: 5 r Q.: > w

Z o

II cc Q-cci i: > o

Q. ^

1^ Q X

i: o o£

fv

•ipj • The boundary that encircles both the OBG and FADA indicates the extent cf the Land Use Ccntrcis (LUCs).

^ J? ^ ^ ^

Legend X—X- RCRA Permitted Fence

Land Use Control Boundary

I I Capped Area

Notes: 1. The LUCs will prevent disturbance cf the capped areas at the OBG. 2. The LUCs wiii include land use restrictions to prevent residential, agricultural, and recreational land use. 3. The OBG entry gate is the only access point to the OBG.

400

GRAPHIC SCALE

800

H Feet



Extent of Land Use Controls at the OBG

^ ARCADIS FIGURE

2-5

Table 2-1 Summary of Residential Risks and Hazards for Constituents of Concern in Soil at the OBG

Exposure Route Arsenic Cadmium Manganese

Exposure Route EPC Adult HQ Child HQ ELCR EPC Adult HQ Child HQ ELCR EPC Adult HQ Child HQ ELCR Ingestion of Soil 9.8 mg/kg 0.045 0.42 2E-05 150.7 mg/kg 0.21 19 ~ 567.2 mg/kg 0.0055 0.052 ~ Dermal Absorption from Soil 9.8 mg/kg 0.0041 0.013 1E-06 150.7 mg/kg 0.28 0.89 ~ 567.2 mg/kg 0.0070 0.022 ~ Inhalation of Particulates 4.9E-7 mg/m ~ ~ 1E-06 7.5E-6 mg/m ~ ~ 8E-06 2.8E-5 mg/m 0.54 1.9 ~ Ingestion of Garden Produce 3.9E-4 mg/kg 0.0053 0.019 2E-06 3.8E-4 mg/kg 0.0016 0.0056 ~ 9.5E-3 mg/kg 0.0003 0.0030 ~ Ingestion of Groundwater 2.2 ug/L 0.020 0.47 5E-05 9.33 pg/L 0.52 1.2 ~ 111.8 pg/L 0.12 0.29 ~ Dermal Absorption from Groundwater 2.2 pg/L 0.00062 0.0010 1E-07 9.33 pg/L 0.024 0.039 ~ 111.8 pg/L 0.0051 0.0083 -Totd: 0.08 0.9 7E-05 1.0 21 8E-06 0.7 2 ~

Exposure Route RDX TNT

Exposure Route EPC Adult HQ Child HQ ELCR EPC Adult HQ Child HQ ELCR Ingestion of Soil 1838.9 mg/kg 0.84 7.8 3E-04 22.1 mg/kg 0.061 0.57 1E-06 Dermal Absorption from Soil 1838.9 mg/kg 1.2 3.6 2E-04 22.1 mg/kg 0.070 0.22 6E-07 Inhalation of Particulates 9.2E-5 mg/m ~ ~ ~ 1.1 E-6 mg/m ~ ~ ~ Ingestion of Garden Produce 120 mg/kg 170 610 4E-02 2.2 mg/kg 18 65 2E-04 Ingestion of Groundwater 55.9 pg/L 0.51 1.2 9E-05 6.9 pg/L 0.38 0.88 3E-06 Dermal Absorption from Groundwater 55.9 pg/L 0.012 0.020 2E-06 6.9 pg/L 0.11 0.17 8E-07 Totd: 173 623 4E-02 19 67 2E-04

ELCR = Excess Lifetime Cancer Risk. EPC = Exposure Point Concentration. HQ = Hazard Quotient. pg/L = Micrograms per liter, mg/kg = Milligrams per kilogram, mg/m = Milligrams per cubic meter. RDX = Cyclotrimethylenetrinitramine. TNT = Trinitrotoluene (2.4.6-).

Table 2-2 Baseline Risk Summary

Potential Receptor Group Carcinogenic Effects Noncarclnogenlc Effects

Potential Receptor Group Carcinogenic Risk COCs Hazard Index* COCs

Current and Probable Future Exposures

OBG/ADA Workers 1 X 10"'^ NR 0.8 NR

Farmers 6x 10"® NR 0.003 NR

Hunters 1 X 10"® NR 0.1 NR

Hypothetical Future Exposures

On-Site Residents (OBG/ADA) 4x 10"^ RDX 700 RDX, TNT**

Notes: * = Maximum cumulative for any target organ

** = Lead may also be considered a COC for residential use of the site. Lead risks are not included in the Hazard Index or in the Carcinogenic Risk.

Chemical of Concern - chemicals accounting for more than 95 % of estimated risk where risk exceeds acceptable range.

COC

NR = Not Relevant-the associated risk is acceptable

TABLE 2-3 List of Retained Constituents of Concern for Risk Evaluations- OBG Area Soil and Groundwater

Chemical Soil Garden Produce Groundwater

Semi-Volatile Oraanic ComDounds fSVOCs): Bis(2-ethylhexyl)phthalate (B2EHP) X

Exolosives: 2,4,6-Trinitrotoluene (246TNT) X X X 2,6-Dinitrotoluene (26DNT) X Cyclotetramethylenetetranitramine (HMX) X Cyclotrimethylenetrinitramine (RDX) X X X

Inorqanics: Arsenic (AS) X X X Cadmium (CD) X X Manganese (MN) X

Notes: Chemical identified a Chemical of Concern (COC) if the cumulative cancer risk for residential exposure to a given media was greater than 1x10 or if the cumulative hazard index (HI) for for residential exposure to a given media was greater than 1.0.

Table 2-4 Risk Characterization Summary for Residential Adults and Children - Carcinogens

Scenario Timeframe: Receptor Population: Receptor Age:

Hypothetical Future Resident Child and Adult

Exposure Exposure Chemical Carcinogenic Risk Medium Medium Point of Concern Ingestion Inhalation Dermal Exposure Route Total

Soil Soil

Soil On-site Direct

Contact 246TNT 1.0E-06 5.9E-07 1.6E-06 Soil On-site

Direct Contact HMX

Soil On-site Direct

Contact RDX 3.0E-04 2.0E-04 5.0E-04 Soil On-site

Direct Contact AS 2.0E-05 1.0E-06 1.0E-06 2.2E-05

Soil On-site Direct

Contact CD 8.00E-06 8.0E-06 Soil On-site

Direct Contact MM

Soil Garden Produce

Ingestion of Produce 246TNT 2.0E-04 NA NA 2.0E-04

Ingestion of Produce HMX NA NA

Ingestion of Produce RDX 4.0E-02 NA NA 4.0E-02

Ingestion of Produce AS 2.0E-06 NA NA 2.0E-06

Ingestion of Produce CD NA NA

Ingestion of Produce MM NA NA

Soil Risk Total = 4E-02 Notes:

-- = Toxicity criteria are not available to quantitatively address this route of exposure. AS = Arsenic. CD= Cadmium.

HMX = Cyclotetramethylenetetranitramine. MM = Manganese. NA = Route of exposure is not applicable to this medium.

RDX = Cyclotrimethylenetrinitramine. 246TNT = 2,4,6-Trinitrotoluene.

Table 2-5 Risk Characterization Summary for Residential Children - Non-Carcinogens

Scenario Timeframe: Hypotheticai Future Receptor Popuiation: Resident Receptor Age: Chiid

Exposure Exposure Chemical Primary Non-Carcinoqenic Hazard Quotient

Medium Medium Point of Concern Target Organ ingestion inhalation Dermal Exposure Route Totai Soii On-site

Direct Soii Soii Contact 246TNT Liver 0.57 ~ 0.22 0.79

Soii On-site Direct

Contact HMX Liver 0.029 — 0.014 0.043 Soii On-site

Direct Prostrate, Contact RDX biood 7.8 ~ 3.6 11

Soii On-site Direct

Contact AS Skin, vascuiar 0.42 ~ 0.013 0.43 Soii On-site

Direct Contact CD Kidney 1.9 ~ 0.89 2.8

Soii On-site Direct

Contact MM CMS 0.052 1.9 0.022 1.974 Garden ingestion of

Soii Produce Produce 246TNT Liver 65 NA NA 65 ingestion of

Produce HMX Liver 23 NA NA 23 ingestion of Prostrate,

Produce RDX biood 610 NA NA 610 ingestion of

Produce AS Skin, vascuiar 0.019 NA NA 0.019 ingestion of

Produce CD Kidney 0.0056 NA NA 0.0056 ingestion of

Produce MM CMS 0.001 NA NA 0.001 Soii Hazard index Totai = 715

Notes: - = Toxicity criteria are not avaiiabie to quantitativeiy address this route of exposure.

AS = Arsenic. CD = Cadmium.

CMS = Centrai nervous system. HMX = Cyciotetramethyienetetranitramine.

MN= Manganese. NA = Route of exposure is not appiicabie to this medium.

RDX = Cyciotrimethyienetrinitramine. 246TNT = 2,4,6-Trinitrotoiuene.

Table 2-6 Risk Characterization Summary for Residential Adults- Non-Carcinogens

Scenario Timeframe: Hypotheticai Future Receptor Popuiation: Resident Receptor Age: Aduit

Exposure Exposure Chemical Primary Non-Carcinoqenic Hazard Quotient

Medium Medium Point of Concern Target Organ ingestion inhalation Dermal Exposure Route Totai Soii On-site

Direct Soii Soii Contact 246TNT Liver 0.061 ~ 0.07 0.13

Soii On-site Direct

Contact HMX Liver 0.0031 — 0.0043 0.0074 Soii On-site

Direct Prostrate, Contact RDX biood 0.84 ~ 1.2 2.0

Soii On-site Direct

Contact AS Skin, vascuiar 0.045 ~ 0.0041 0.049 Soii On-site

Direct Contact CD Kidney 0.21 ~ 0.28 0.49

Soii On-site Direct

Contact MM CMS 0.0055 0.54 0.007 0.55 Garden ingestion of

Soii Produce Produce 246TNT Liver 18 NA NA 18 ingestion of

Produce HMX Liver 6.4 NA NA 6.4 ingestion of Prostrate,

Produce RDX biood 170 NA NA 170 ingestion of

Produce AS Skin, vascuiar 0.0053 NA NA 0.0053 ingestion of

Produce CD Kidney 0.0016 NA NA 0.0016 ingestion of

Produce MM CMS 0.00028 NA NA 0.00028 Soii Hazard index Totai = 198

Notes: - = Toxicity criteria are not avaiiabie to quantitativeiy address this route of exposure.

AS = Arsenic. CD = Cadmium.

CMS = Centrai nervous system. HMX = Cyciotetramethyienetetranitramine.

MN= Manganese. NA = Route of exposure is not appiicabie to this medium.

RDX = Cyciotrimethyienetrinitramine. 246TNT = 2,4,6-Trinitrotoiuene.

Table 2-7 Comparative Analysis of Alternatives

CERCLA FS Criteria

A B c F

CERCLA FS Criteria No Action Limited Action (rontainment

(Engineered (raps) CERCLA FS Criteria No Action Limited Action

Asphalt GCF

Tlu

esho

ld C

rite

ria

Protects human health and environment X X V N/

Tlu

esho

ld C

rite

ria

Meets Applicable or Relevant and Appropriate Requirements

Chemical Specific NA NA NA NA

Tlu

esho

ld C

rite

ria

Meets Applicable or Relevant and Appropriate Requirements

Location Specific NA NA NA NA

Tlu

esho

ld C

rite

ria

Meets Applicable or Relevant and Appropriate Requirements Action

Specific NA NA N/ N/

Prim

aiy

Bal

anci

ng C

rite

ria

Provides long-term effectiveness and peiTnanence

X X V v/

Prim

aiy

Bal

anci

ng C

rite

ria

Reduces Mobility . toxicit> and volume X X N/ N/

Prim

aiy

Bal

anci

ng C

rite

ria

Provides shoi1-teiTn effectiveness NA V V V

Prim

aiy

Bal

anci

ng C

rite

ria

Implementable V N/ V

Prim

aiy

Bal

anci

ng C

rite

ria

Capital Cost

Total Alternative GAM Costs

Total

$0 $119,794 $2,013,157 Prim

aiy

Bal

anci

ng C

rite

ria

Capital Cost


Total

$0 $s74.o:s $988,605 $1,427,040

Prim

aiy

Bal

anci

ng C

rite

ria

Capital Cost


Total $0 $99^. s:i $4,839,743 $3,440,198

Mod

ifSi

ng

Cri

teri

a State agency acceptance

Mod

ifSi

ng

Cri

teri

a

Communit> Acceptance

Notes: v/ = Meets or Exceeds criterion

X = Does not meet criterion

Table 2-8 Cost Estimate for Alternative F: Engineered Caps (GCL-based)

Ileni I'lii Is Qiinn lily Capilal CosI

in 2010 Annual 0«S:M CosI in 2010

Tolai 0«&M CosI H1III DiiralJon of

30 YEARS al "<»o*

Tola! .AllernalJve

Cosis

Adininislradve AclJons

Eiigijieeriiig (Remedial) Design Remedid Aclion (Consiniclion Work Phms) Pre-Consiniclion Engineering Prociiremeni of Materials and Services

_Consmiclion^om£lelioi^^e£^

,100.()()()

S"5.ooo $50 $50 ,100

000

000

000

,100.000 $"5,000 $50 $50 ,100

000

000

000

Siiblolai: 000 $0 $0 000

General .Action Sile PreparalJon Supplemenid Characterization for Design Support Pre-Constniction Field Siunpling Mobilization Demobilization Submit tds Cleiiring of liglit trees iind bnish ($10,000 .Acre) SOt Fence ($5 LF) Surveying Engineered Caps General fiU above grade and below Ihier subgrade. placed iind compacted ($38 C"i') (1) Geosynthetic Clay Liner($32 S"i') (1) Compacted Cap ($2o C"i') (1) TopsoO ($15 C"i') (1) Hydroseed Fertilizer, iind Mulch ($3,500 .Acre) (1)

.Acre

LF

LW

S^' LW LW

.Acre

3000

8.500

6.800 6.800 1.200

5200 5100 $20 $20 $15 $20

000 000 000

000

000 000

$323,000 $21" $136 $18

600 000 000

000

5200 5100 $20 $20 $15 $20

000 000 000

000

000 000

$323,000 $21" $136 $18

600 000 000

000

Siiblolai: $l.o"6 "54 $0 $0 $l.o"6 "54 SUBTOTAL (I and II) $1,451 '54 $0 $0 $1,451 '54

III Long Term Monlloring. Review .And Mainlenance .Administration Engineered Cap Maintenance'^ Report ing'^ 5-\ear Review^

Each Each Each Each

30 30 30 6

550.00 530.00 530.00 525.00

$620,452 $3"2.2"1 $3"2.2"1 $62,045

$620,452 $3"2.2"1 $3"2.2"1

$62,045

Siiblolai: $0 $135.00 $1.42".o4o $1.42".o4o

SUBTOTALd. 11. andlll) $1.451."54 $135,000 $1.42".040 $2.8"8."94 lY .Addllonal Syslein CosIs

UX(;)-related support (5o®o of direct coiLstnictiou) Health & Safetv (5®o of direct coiLstnictiou)

$350.8"" $35,088

$350.8' $35,088

Siiblolai: $385,965 $0 $0 $385,965 SUBTOTAL (1. 11. Ill, and IV) $1.83"."19 $135,000 $1.42".040 $3.264."58

Iinpieinenlalion CosIs Qiuihty Control Testing (lo®o of ilirect constniction) Field Endneerina (15®o of ilirect constniction)

$"o.l"5 ,105.263

$"o.r $105,263

Siiblolai: $1"5.439 $0 $0 $1"5.439 .A Tolai Capilal CosIs B .Anniiai CosI (firsl year) C Tolai .Allernalive 0«&M CosIs

$2,013.15' $135,000

$1.42".o4o

Tolai Capilai .And .Anniiai CosIs (.A + C ) $3,440,198

Notes: Groundwiater monitoring costs have not been included because groiuidwater will

.Ajuiual costs are discoiuited "®o per year from 2oo9 for 3o years in accordance Fcdsibilily Sli/Jv (USEPAJuly 2ooo). (1) direct coiLstniction costs

be addressed luider another response action. wit h .4 Guide lo Developing and Docuinenling d'osl EsliinaJes During I he

TABLE 2-9 ARARs and TBCs for the Selected Remedy

Action Requirements Prerequisite Citation(s) ARAR or TBC

General Construction Standards—All Land-disturbing Activities (Le., Cap Installation)

Activities causing fugitive dust emissions

Shall take reasonable precautions to prevent particulate matter from becoming airborne; reasonable precautions shall include, but are not limited to, the following:

Fugitive emissions from demolition of existing buildings or structures, construction operations, grading of roads, or the clearing of land—applicable

TDEC 1200-3-8-.01(l) TBC

• use, where possible, of water or chemicals for control of dust, and

TDEC 1200-3-8-.01(l)(a) TBC

• application of asphalt, oil, water, or suitable chemicals on dirt roads, materials stock piles, and other surfaces which can create airborne dusts;

TDEC 1200-3-8-.01(l)(b) TBC

Shall not cause or allow fugitive dust to be emitted in such a manner as to exceed 5 minute/hour or 20 minute/day beyond property boundary lines on which emission originates

TDEC 1200-3-8-.01(2) TBC

Activities causing storm water runoff (e.g., clearing, grading, excavation)

Implement good construction management techniques (including sediment and erosion controls, vegetative controls, and structural controls) in accordance with the substantive requirement of Genera/i'erwnYiVb. TNRlO-0000 to ensure that storm water discharge:

Dewatering or storm water runoff discharges from land disturbed by constmction activity— disturbance of >1 acre of total land —applicable

TCA 69-3-1080)

TDEC 1200-4-10-.03(2)

TBC

TBC

• does not violate water quality criteria as stated in TDEC 1200-4-3-.03 including but not limited to prevention of discharges that causes a condition in which visible solids, bottom deposits, or turbidity impairs the usefulness of waters of the state for any of the designated mes for that water body by TDEC 1200-4-4

Storm water discharges from construction activities -TBC

General Permit No. TNRlO-0000

Section 4.3.2(a)

TBC

• does not contain distinctly visible floating scum, oil, or other matter;

General Permit No. TNRl0-0000

Section 4.3.2(b)

TBC

• does not cause an objectionable color contrast in the receiving stream; and


Section 4.3.2(c)

TBC

• results in no materials in concentrations sufficient to be hazardous or otherwise detrimental to humans, livestock, wildlife, plant life, or fish and aquatic life in the receiving stream


Section 4.3.2(d)

TBC

Page 1 of?



Waste Generation, Characterization, Segregation, and Storage—Secondary Wastes (e.g., contaminated PPE or equipment)

Characterization of solid waste

Must determine if solid waste is excluded from regulation under 40 CFR 261.4(b); and

Generation of solid waste as defined in 40 CFR 261.2 —applicable

40 CFR 262.11(a)

TDEC 1200-l-ll-.03(l)(b)(l)

ARAR

TBC

Mmt determine if waste is listed as hazardous waste in Subpart D of 40 CFR Part 261; or

Generation of solid waste which is not excluded under 40 CFR 261.4(a)— applicable

40 CFR 262.11(b)

TDEC 1200-l-ll-.03(l)(b)(2)

ARAR

TBC

Must determine whether the waste is (characteristic waste) identified in subpart C of 40 CFR part 261by either:

(1) Testing the waste according to the methods set forth in subpart C of 40 CFR part 261, or according to an equivalent method approved by the Administrator under 40 CFR 260.21; or

40 CFR 262.11(c)

TDEC 1200-l-ll-.03(l)(b)(3)

ARAR

TBC

(2) Applying knowledge of the hazard characteristic of the waste in light of the materials or the processes used.

Must refer to Parts 261,262, 264, 265, 266, 268, and 273 of Chapter 40 for possible exclusions or restrictions pertaining to management of the specific waste.

Generation of solid waste which is determined to be hazardoiK - applicable

40 CFR 262.11(d);

TDEC 1200-l-ll-.03(l)(b)(4)

ARAR

TBC

Characterization of hazardous waste

Must obtain a detailed chemical and physical analysis on a representative sample of the waste(s), which at a minimum contains all the information that must be known to treat, store, or dispose of the waste in accordance with pertinent sections of 40 CFR 264 and 268.

Generation of RCRA-hazardous waste for storage, treatment or disposal—applicable

40 CFR 264.13(a)(1)

TDEC 1200-l-ll-.06(2)(d)(l)

ARAR

TBC

Determinations for management of hazardous waste

Must determine each EPA Hazardous Waste Number (waste code) apphcable to the waste in order to determine the applicable treatment standarchi under 40 CFR 268 et seq..

Note: This determination may be made concurrently with the hazardom waste determination required in Sec. 262.11 of this chapter.

Generation of hazardous waste for storage, treatment or disposal - applicable

40 CFR 268.9(a)

TDEC 1200-l-ll-.10(l)(i)(l)

ARAR

TBC

Determinations for management of hazardous waste {continued)

Must determine the underlying hazardous constituents [as defmed in 40 CFR 268.2(i)] in the characteristic waste

Generation of RCRA characteristic hazardous waste (and is not DOOl non-wastewaters treated by CMBST, RORGS, or POLYM of Section 268.42 Table 1) for storage, treatment or disposal - applicable

40 CFR 268.9(a) TDEC 1200-l-ll-.10(l)(i)(l)

ARAR TBC

Page 2 of 7



Must determine if the hazardous waste meets the treatment standards in 40 CFR 268.40, 268.45, or 268.49 by testing in accordance with prescribed methods or use of generator knowledge of waste.

Note: This determination can be made concurrently with the hazardous waste determination required in 40 CFR 262.11.

Generation of hazardous waste for storage, treatment or disposal - applicable

40 CFR 268.7(a)

TDEC 1200-l-ll-.10(l)(g)(l)(i)

ARAR

TBC

Temporary storage of hazardous waste in containers

A generator may accumulate hazardous waste at the facility provided that:

• waste is placed in containers that comply with 40 CFR 265.171-173; and

Accumulation of RCRA hazardous waste on site as defined in 40 CFR 260.10— applicable

40 CFi? 262.34(a);

TDEC 1200-l-ll-.03(4)(e)

40CFii262.34(a)(l)(i);

TDEC 1200-l-ll-.03(4)(e)(2)(ii)(l)

ARAR

TBC

ARAR

TBC


• the date upon which accumulation begins is clearly marked and visible for inspection on each container

40 CFR 262.34(a)(2);

TDEC 1200-l-ll-.03(4)(e)(2)(ii)

ARAR

TBC


• container is marked with the words "hazardous waste" or 40 CFR 264.34(a)(3)

TDEC 1200-l-ll-.03(4)(e)(2)(iv)

ARAR

TBC


• container may be marked with other words that identify the contents

Accumulation of 55 gal. or less of RCRA hazardous waste or one quart of acutely hazardous waste listed in 261.33(e) at or near any point of generation - applicable

40 CFR 262.34(c)(1)

TDEC 1200-l-ll-.03(4)(e)(5)(i)(n)

ARAR

TBC

Use and management of hazardous waste in containers

If container is not in good condition (e.g. severe rusting, structural defects) or if it begins to leak, must transfer waste into container in good condition

Storage of RCRA hazardous waste in containers—applicable

40 CFR 265.171

TDEC 1200-l-ll-.05(9)(b)

ARAR

TBC


Use container made or lined with materials compatible with waste to be stored so that the ability of the container is not impaired

40 CFR 265.172

TDEC 1200-l-ll-.05(9)(c)

ARAR

TBC


Keep containers closed during storage, except to add/remove waste

40 CFR 265.173(a)

TDEC 1200-l-ll-.05(9)(d)(l)

ARAR

TBC

Use and management of hazardous waste in containers {continued)

Open, handle and store containers in a manner that will not cause containers to rupture or leak

40 CFR 265.173(b)

TDEC 1200-l-ll-.05(9)(d)(2)

ARAR

TBC

Page 3 of 7



Storage of hazardous waste in container area

Area must have a containment system designed and operated in accordance with 40 CFR 264.175(b)

Storage of RCRA-hazardous waste in containers with free liquids—applicable

40 CFR 264.175(a)

TDEC 1200-l-ll-.06(9)(f)(l)

ARAR

TBC

Area must be sloped or otherwise designed and operated to drain liquid from precipitation, or

Containers must be elevated or otherwise protected from contact with accumulated liquid

Storage of RCRA-hazardous waste in containers that do not contain free liquids — applicable

40 CFR 264.175(c)

TDEC 1200-l-ll-.06(9)(f)(3)

ARAR

TBC

Capping Waste In Place

Standards for inactive asbestos waste disposal sites

Must comply with one of the following:

• either discharge no visible emissions to the outside air from an inactive disposal site subject to this paragraph; or

Closure of an area that received asbestos containing waste materialsCrelevant and appropriate

TDEC 1200-3-ll-.02(2)(I)

TDEC 1200-3-ll-.02(2)(I)(l)(i)

TBC

TBC

• Cover the asbestos-containing waste material with at least 15 centimeters (6 inches) of compacted nonasbestos-containing material, and grow and maintain a cover of vegetation on the area to prevent exposure of the asbestos-containing waste material; or

TDEC 1200-3-ll-.02(2)(I)(l)(ii) TBC

• Cover the asbestos-containing waste material with at least 60 centimeters (2 feet) of compacted nonasbestos-containing material, and maintain it to prevent exposure of the asbestos-containing waste; or

TDEC 1200-3-ll-.02(2)(I)(l)(iii) TBC

Install and maintain warning signs and fencing as follows:

• Display warning signs at all entrances and at intervals of 100m 9328 feet) or less along the property line of the site or along the perimeter of the sections of the site where asbestos-containing waste material was deposited.

Closure of an area that received asbestos containing waste materials that does not include a natural barrier to adequately deter access b y the general publicCrelevant and appropriate

TDEC 1200-3-ll-.02(2)(I)(2)(i) TBC

The warning signs must be posted in a manner and location as prescribed in TDEC 1200-3-11-.02(2)(I)(2)(i)(I) thru (I II)

TDEC 1200-3-ll-.02(2)(I)(2)(i) TBC

Fence the perimeter of the site in a manner adequate to deter access by the general public.

TDEC 1200-3-ll-.02(2)(I)(2)(ii) TBC

Page 4 of 7



Standards for inactive asbestos waste disposal sites {continued)

May use an alternative control method that has received prior approval of the EPA or TDEC.

TDEC 1200-3-Il-.02(2)(l)(3) TBC

Landfill closure performance standard

Must close the unit in a manner that:

• Minimizes the need for further maintenance; and

Closure of a Class II solid waste disposal facility -relevant and appropriate

TDEC I200-I-7-.04(8)(a)(I)(i) TBC

• Controls, minimizes, or eliminates to the extent necessary to prevent threats to public health and the environment, post-closure escape of solid waste, solid waste constituents, leachate, contaminated rainfall, or waste decomposition products to ground or surface waters or to the atmosphere.

TDEC I200-I-7-.04(8)(a)(l)(ii) TBC

Landfill cover design and construction

A compacted final cover material (e.g., soil) shall be placed on the disposal facility in the shortest practicable time, after achieving fmal grade of any fill area.

Closure of a Class n solid waste disposal facility -relevant and appropriate

TDEC 1200-I-7-.04(8)(c)(3) TBC

The fmal depth of final cover system shall be at least 36 inches of soil of which a minimum of 12 inches shall be for the support of vegetative cover.

TDEC I200-I-7-.04(8)(c)(3)(i) TBC

The design of the fmal cover system shall be a design which includes a compacted soil layer of at least 24 inches and has a permeability no greater than 1 x 10"^ cm/sec. This design shall be supported by use of the HELP model or other equivalent model approved by TDEC and EPA.

An alternate final cover system may be used provided that it is demonstrated to the satisfaction of TDEC and EPA that the fmal cover system provides equivalent or superior performance to the minimum performance standard in this subpart.

Post-Closure Care and Institutional Controls for Waste Left-In-Place

General post-closure care for closed landfill

Owner or operator must:

• Maintain the approved fmal contours and drainage system of the site such that the objectives of TDEC Rule 1200-l-7-.04(8)(c)(4) are continuously met;

Closure of a Class n solid waste disposal facility - relevant and appropriate

TDEC 1200-I-7-.04(8)(e)(l) TBC

Page 5 of 7


Action Requirements Prerequisite Citation^) ARAR or TBC

• Ensure that a healthy vegetative cover is established and maintained over the site; and

TDEC 1200-l-7-.04(8)(e)(2) TBC

• Maintain the drainage facilities, sediment ponds, and other erosion/sedimentation control measures (if such are present at the landfill), at least until the vegetative cover is established sufficiently to render such maintenance unnecessary.

TDEC 1200-l-7-.04(8)(e)(3) TBC

Deed notice for asbestos waste disposal site

Record, in accordance with State law, a notation on the deed to the facility property and on any other instrument that would normally be examined during a title search; this notation will in perpetuity notify any potential purchaser of the property that:

• The land has been used for disposal of asbestos-containing waste material; and

• The survey plat and record of the location and quantity of asbestos containing waste disposed of within the disposal site.

Closure of an area that received asbestos containing waste materialsCrelevant and appropriate

TDEC 1200-3-ll-.02(2)(l)(5) TBC

Post-closure notices for closed landfill

Must ensure that within 90 days of final closure of the facility and prior to sale or lease of the property on which facility is located, there is recorded, in accordance with State law, a notation on the deed to the property - or on some other instrument which is normally examined during a title search -that will in perpetuity notify any person conducting a title search that the land has been used as a disposal facility and its use is restricted.

Closure of a Class n solid waste disposal facilityCrelevant and appropriate

TDEC l200-l-7-.04(8)(f) TBC

Transportation of Wastes

Transportation of hazardous materials

Shall be subject to and must comply with all applicable provisions of the HMTA and HMR at 49 CFR 171-180 related to marking, labeling, placarding, packaging, emergency response, etc.

Any person who, under contract with a department or agency of the federal government, transports "in commerce," or causes to be transported or shipped, a hazardous material —applicable

49 CFR 171.1(c) ARAR

Page 6 of 7



Transportation of hazardous waste off site

Must comply with the generator requirements of 40 CFR 262.20-23 for manifesting, Sect. 262.30 for packaging. Sect. 262.31 for labeling. Sect. 262.32 for marking. Sect. 262.33 for placarding and Sect. 262.40, 262.41(a) for record keeping requirement and Sect. 262.12 to obtain EPA ED number.

Preparation and initiation of shipment of hazardous waste off-site— applicable

40 CFR 262.10(h)

TDEC 1200-l-ll-.03(l)(a)(8)

ARAR

TBC

ARAR = applicable or relevant and appropriate requirement CFR = Code of Federal Regulations CWA = Clean Water Act of 1972 NPDES = National Pollutant Discharge Elimination System DEACT = deactivation DOT = U.S. Department of Transportation

EPA = U.S. Environmental Protection Agency RCRA = Resource Conservation and Recovery Act of 1976 HMR = Hazardous Materials Regulations HMTA = Hazardous Materials Transportation Act TBC = to be considered

TCA= Tennessee Code Annotated TDEC = Rules of theTennessee Department of

Environment and Conservation, Chapter as noted UTS = Universal Treatment Standard

Page 7 of 7