supplemental site investigation report

SUPPLEMENTAL SITE INVESTIGATION REPORT

For

Hinesburg Jolley Mobil 21 Commerce Street

Hinesburg, VT

Vermont DEC Site #2011-4243 375 feet AMSL

44°19’59.76”N 73°06’38.96”W

August 8, 2012

Prepared for:

S.B. Collins, Inc. 54 Lower Weldon Street

St Albans, VT 05478

Prepared by:

368 Avenue D, Suite 15

P.O. Box 787 Williston, VT 05495

(802) 383-0486 (ph), (803) 383-0490 (fax) www.kas-consulting.com

KAS Job# 409110442

Supplemental Site Investigation Report Hinesburg Jolley Mobil, Hinesburg, Vermont

08/15/2012 VTDEC Site #2011-4243

TABLE OF CONTENTS

1.0 INTRODUCTION .................................................................................................................. 1

2.0 SCOPE OF WORK ................................................................................................................. 1

3.0 SITE DESCRIPTION .............................................................................................................. 1

3.1 SITE AND VICINITY ................................................................................................................ 1 3.2 SITE AND AREA FEATURES, TOPOGRAPHY, SURFACE WATER BODIES, AND DRAINAGE ........................ 1 3.3 ABUTTERS AND NEARBY PROPERTIES ........................................................................................ 2 3.4 UTILITIES ............................................................................................................................ 2 3.5 PREVIOUS HAZARDOUS MATERIALS RELEASES AND SITE HISTORY .................................................. 2

4.0 SUBSURFACE EXPLORATIONS AND LABORATORY ANALYSES .......................................... 3

4.1 PRE-DRILLING ACTIVITIES ...................................................................................................... 3 4.2 MONITORING WELL INSTALLATION AND FIELD SCREENING OF SUBSURFACE SOILS ............................. 3 4.3 GROUNDWATER FLOW DIRECTION AND GRADIENT ..................................................................... 4 4.4 GROUNDWATER SAMPLING AND LABORATORY ANALYSIS ............................................................. 4

5.0 SITE HYDROGEOLOGY ........................................................................................................ 5

5.1 CONTAMINANT DISTRIBUTION ................................................................................................ 5 5.1.1 Soil ............................................................................................................................... 5 5.1.2 Groundwater ............................................................................................................... 5

6.0 CONCEPTUAL HYDROGEOLOGIC MODEL ........................................................................... 6

6.1 SITE CONDITIONS ................................................................................................................. 6 6.2 GEOLOGY ........................................................................................................................... 6 6.3 HYDROGEOLOGY .................................................................................................................. 6 6.4 APPARENT SOURCE OF CONTAMINATION .................................................................................. 7 6.5 CONTAMINANT TRANSPORT ................................................................................................... 7 6.6 SENSITIVE RECEPTOR RISK ASSESSMENT ................................................................................... 7

6.6.1 Buildings in the Vicinity ............................................................................................... 7 6.6.2 Utility Corridors ........................................................................................................... 7 6.6.3 Surface Water Bodies .................................................................................................. 8 6.6.4 Water Supplies ............................................................................................................ 8

6.7 IMPACTED THIRD PARTIES ...................................................................................................... 8

7.0 CONCLUSIONS .................................................................................................................... 8

8.0 RECOMMENDATIONS ......................................................................................................... 9

9.0 REFERENCES ........................................................................................................................ 9


08/15/2012 VTDEC Site #2011-4243

APPENDICES Appendix A. Maps Appendix B. Soil Boring Logs and Monitoring Well Construction Diagram Appendix C. Liquid Level Monitoring Data Appendix D. Groundwater Quality Summary Data Appendix E. Groundwater Analytical Laboratory Report


08/15/12 i VTDEC Site #2011-4243

EXECUTIVE SUMMARY A Supplemental Site Investigation has been completed by KAS, Inc. (KAS) at the Hinesburg Jolley Mobil. The Hinesburg Jolley Mobil property (herein referred to as “Site”) is located at 21 Commerce Street Hinesburg, Vermont (VTDEC Site #2011-4243). The Site is currently used as a convenience store and gasoline/diesel station. Contamination was encountered in soils beneath the Site during the removal of three 10,000-gallon capacity gasoline underground storage tanks (USTs) on September 26-27, 2011. Soils in the vicinity of the removed USTs had volatile organic compound (VOC) concentrations of up to 2,879 ppm when subjected to headspace soils testing using properly calibrated Mini-Rae photoionization detector (PID). Saturated soils were encountered in the excavation at a depth of approximately 4 feet below surface grade. Native soils consisted of mostly gray clays. The limits of the contamination were not defined during the UST closure assessment dated September 28, 2011. As part of the Initial Site Investigation, KAS supervised the installation of four groundwater monitoring wells at the Site (MW12-01 through MW12-04) on February 1, 2012. PID soil screening results from the borings ranged from 0.0 to 568.8 ppm. Petroleum odors were noted in soils during the installation of three of the four monitoring wells. Groundwater analytical data collected at the Site in February 2012 indicate that dissolved petroleum constituents (VOCs) are present at concentrations above Vermont Groundwater Enforcement Standards (VGES) in groundwater in three of the four monitoring wells (MW12-01-MW12-03). Total petroleum hydrocarbons (TPH) and gasoline range organics (GRO) were reported in three of the monitoring wells at concentrations ranging from 40.2 to 62.6 mg/L. Based on the results of the initial site investigation conducted at the Hinesburg Site, KAS recommended further development of more soil borings and ground water monitoring wells to help determine the extent of the contamination plume. Four additional downgradient groundwater monitoring wells were installed, and all on site wells were sampled. A surface water sample could not be collected due to dry conditions.Groundwater flow is generally towards to north/northwest at a shallow gradient of 2.0%. Contamination levels across the site are at moderate levels, and based on data collected to date the source area appears to be located in the vicinity of MW12-03. Sensitive receptors identified to be at risk of petroleum contamination on Site include soil and groundwater, surface waters to the north of the source area and a drainage culvert located downgradient of the source area.

Initial Site Investigation Report Hinesburg Jolley Mobil, Hinesburg, Vermont

08/15/12 1 VTDEC Site #2011-4243

1.0 INTRODUCTION

This report provides a summary of the methodology, results, conclusions, and recommendations completed as part of the Supplemental Site Investigation at the Hinesburg Jolley Mobil, property located at 21 Commerce Street in Hinesburg, Vermont (see Site Location Map, Appendix A). This work was performed in accordance with the Work Plan and Cost Estimate for a Supplemental Site Investigation at the Site dated June 13, 2012 prepared by KAS, Inc. (KAS). The Supplemental Site Investigation was approved by Ms. Lynda Provencher of the Vermont Department of Environmental Conservation (VTDEC) in an electronic mail message to KAS, dated June 15, 2012.

2.0 SCOPE OF WORK

This Supplemental Site Investigation was conductedto further asses the degree and extent of petroleum impact to soil and groundwater in the vicinity of the underground storage tanks (USTs) located on the Site.Contamination was encountered in soils beneath the Site during the removal of three 10,000-gallon gasoline USTs on September 26-27, 2011. Results of the following investigative tasks performed by KAS are presented: soil boring advancement and monitoring well installation; soil screening; groundwater sampling and analysis; and evaluation of sensitive receptors in the vicinity of the Site.

3.0 SITE DESCRIPTION

3.1 Site and Vicinity

The Site is located on the east side of Route 116 and just north of Commerce Street (Site Location Map, Appendix A). As of the date of this report, the Site was used as a convenience store and gasoline/diesel station. The Site is occupied by one building on the eastern and center part of the property. The building is located approximately 30 feet from the formerUSTs and 60 feet to current USTs. The gasoline dispensers and canopy are located on the western side of the property approximately 20-30 feet from the Site building. A paved parking lot occupies the remainder of the Site.The Site Map (Appendix A) shows the Site and relevant Site features.

3.2 Site and Area Features, Topography, Surface Water Bodies, and Drainage

Based on a review of the topographic map and aerial photograph included in Appendix A, the Site lies at an approximate elevation of 375 feet above mean sea level (AMSL). The coordinates of the property at the site entrance are approximately 44o 19’ 59.76” latitude and -73o 06’ 38.96’’ Longitude. Topography on the Site property is generally flat throughout with a very slight slope to the south. A small unnamed river and associated wetlandsare the closest surface water to the Site, located approximately 200feet north of the USTs.Based on Site topography,


08/15/12 2 VTDEC Site #2011-4243

the surface drainage from the Site is anticipated to flow to the north and west towards Rt 116. One storm water drainage catch basin was noted along Rt 116.

3.3 Abutters and Nearby Properties

The land use in the surrounding area consists of commercial properties (see Area Map, Appendix A). The nearest neighboring building is located approximately 150 feet west of the former USTs, but is across Rt 116. This building is occupied by a new Kinney Drugs. The northern part of the property is abutted by grass and about 200 feet farther north appears to be a small patch of wetland. To the south of the Site across Commerce Street is commercial property with a hardware store and a medical office. To the east up a small incline is a car-towing business.

3.4 Utilities

Public utilities in the area include telephone, electricity, water, and sewer. Electric and telephone lines are located overhead and are located about 100 feet to the west of the Site. Water and sewer are obtained from the Town of Hinesburg and are located underground. Bordering the very southern edge of the Site are underground natural gas linesalong Commerce Street, but do not appear to enter the building on the Site.

3.5 Previous Hazardous Materials Releases and Site History

Contamination was encountered in soils beneath the Site during the removal of three 10,000-gallon gasoline USTs on September 26-27, 2011. Soils in the vicinity of the removed USTs had VOC concentrations of up to 2,879 ppm when subjected to headspace soils testing using properly calibrated Mini-Rae photoionization detector (PID). Saturated soils were encountered in the excavation at a depth of approximately 4 feet below surface grade. Native soils consisted of mostly gray clays. The limits of the contamination were not defined during UST closure assessment dated September 26-27, 2011. Petroleum is composed of aliphatic hydrocarbons, olefinic hydrocarbons, and aromatic hydrocarbons. The main contaminants of concern from the suspected petroleum release at the Site are benzene, toluene, ethylbenzene, xylenes, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, and naphthalene. No other releases of hazardous materials are known to have occurred on the Site and thus no other contaminants of concern are noted. A material safety data sheet (MSDS) for gasoline is available on line at www.msds.com/.


08/15/12 3 VTDEC Site #2011-4243

4.0 SUBSURFACE EXPLORATIONS AND LABORATORY ANALYSES

4.1 Pre-Drilling Activities

Prior to the initiation of subsurface activities at the Site, a Health and Safety Plan (HASP) was prepared in accordance with Occupational Safety and Health Administration (OSHA) requirements. The Site was pre-marked on June 26, 2012. DigSafe Number 20122604583 was obtained prior to the drilling activities. The Town of Hinesburg was also contacted for clearance of drilling locations related to any underground utilities that may be in the area.All nearby underground utilities are indicated on the Site Map included in Appendix A.

4.2 Monitoring Well Installation and Field Screening of Subsurface Soils

Four soil borings, which were completed as monitoring wells MW12-05 through MW12-08, were advanced at the Site on July 3, 2012 by T&K Drilling of Troy, New Hampshire under the direct supervision of a KAS scientist. The soil borings were advanced using a hollow stem auger drill rig. The monitoring well and soil boring locations are indicated on the Site Map (Appendix A). Soil samples were collected from the borings at intervals of 0-2 feet, 5-7 feet, and 10-12 feet. The soil samples were logged by the supervising scientist and screened for the presence of VOCs using aMiniRaeLite model PID. Prior to screening, the PID was calibrated with isobutylene referenced to benzene on July 3, 2012. Soils were screened using the KASPolyethylene Bag Headspace Screening Protocol. Soil characteristics and contaminant concentrations were recorded by the KAS scientist in detailed soil boring logs and monitoring well construction diagrams presented in Appendix B. Following the soil boring advancement and well installation, the location of the borings and top of casing elevation of the new wells were surveyed relative to an existing datum. The monitoring well and soil boring locations are indicated on the Site Map (Appendix A). Subsurface Sediments Subsurface sediments encountered in the four soil borings consisted mostly of lean clay mixed in varying amounts with sand and gravel.Groundwater was observed at approximately 7.5 to 10 feet below surface grade (bsg) on the day of drilling. Bedrock refusal was not encountered in any of the borings to a maximum depth of 11 feet bsg. Monitoring wells MW12-05, -06, and -07 were installed at a depth of 11 feet bsg, and MW12-08 was installed at a depth of 10 feet bsg. PID readings above background were observed in soil samples collected from two of the four borings at various depths. The elevated PID readings ranged from 2.5 to 86.0 parts per million (ppm). A petroleum odor was noted in soil samples collected during theadvancement for MW12-05. Two 55-gallon drums were filled with the soil cuttings. Arrangements have been made to remove the drummed waste.


08/15/12 4 VTDEC Site #2011-4243

4.3 Groundwater Flow Direction and Gradient

Depth to groundwater measurements were collected from all eight monitoring wells (MW12-01 through MW12-08) on July 20, 2012. The well locations are shown on the Site Map in Appendix A. The depth to water was subtracted from the top-of-casing elevation to obtain the relative water table elevation. Light non-aqueous phase liquid (LNAPL) was not measured or observed in any of the eightmonitoring wells. Depth to groundwater ranged from 4.95 feet bsg in MW12-04 to 6.75 feet bsgin MW12-05. Liquid level monitoring data are presented in Appendix C. Water table elevations were plotted and contoured to illustrate the estimated gradient and direction of groundwater flow beneath the Site (see the Groundwater Contour Map, Appendix A). According to the data, groundwater is flowing to the west-northwest at an average hydraulic gradient of 2.0%. Based on this groundwater flow regime, monitoring well MW12-03 is located in the source area, monitoring wellsMW12-01, -02, -05, -06, -07 and -08 are located down-gradient and monitoring well MW12-04 is located up-gradient to the former USTs.

4.4 Groundwater Sampling and Laboratory Analysis

Groundwater samples were obtained from all Site monitoring wells on July 20, 2012. A wetland sample could not be obtained on this date due to dry conditions. All samples were collected according to KAS’ Monitoring Well Sampling Protocol. For Quality Assurance/ Quality Control (QA/QC) purposes, one trip blank and one duplicate sample were submitted along with the groundwater samples collected during the sampling event. The groundwater samples collected on July 20, 2012 were submitted to Endyne for laboratory analysis of volatile organic compounds (VOCs) by EPA Method 8021B. The groundwater analytical results for the July 20, 2012 sampling event were compared to the Vermont Groundwater Enforcement Standards (VGES). Tabulated groundwater results can be found in Appendix D. A copy of the laboratory report is included in Appendix E. There were no contaminants reported above laboratory detection limits in the sample obtained from MW12-04. Several of the tested compounds were reported above the VGES in the groundwater sample collected from the remaining sevenmonitoring wells on July 20, 2012. Two or more of the tested compounds were reported above the laboratory reporting limits but below the VGES in each of the seven wells as well. The total reported VOC concentrations ranged from81.1 (MW12-07) to 18,186 (MW12-02) ug/L (ppb).


08/15/12 5 VTDEC Site #2011-4243

The results of the laboratory analysis of the duplicate sample were analyzed using a relative percent difference (RPD) analysis. The RPD is defined as 100 times the difference in reported concentration between sample and duplicate, divided by the mean of the two samples. A small RPD indicates good correlation between sample and duplicate. The duplicate sample was collected from monitoring well MW12-02 on July 20, 2012. RPD values ranged from 1.1% for ethylbenzene to 14.1% for naphthalene. A tabular presentation of duplicate sample data and RPD results is included in Appendix D. Lack of spurious influence on sample results was demonstrated by none of the tested VOCs reported above detection limits in the trip blank collected on July 20, 2012.

5.0 SITE HYDROGEOLOGY

5.1 Contaminant Distribution

5.1.1 Soil

Based on a review of field screening data collected at the Site, it appears low levels of petroleum impacts to soils are present in the vicinity of and down-gradient to the former UST tank pit at depths ranging from 2 to 10 feet bsg. Generally, the highest PID readings in soils were recorded within the saturated zone. A petroleum odor was noted in soil samples collected from the soil boringof MW12-05. Saturated soils were encountered in a lean clay layer at an approximate depth of 7.5 to 10 feet. The low PID readings observed in the soil boring at MW12-07 indicates that the adsorbed phase contamination does not extend significantly to the west. The high PID readings at MW12-05 and lower readings at adjacent well MW12-06 suggest that MW12-05 may be directly downgradient to the source.Soil Boring Logs and Monitoring Well Construction Logsare included in Appendix B.

5.1.2 Groundwater

Groundwater analytical data collected at the Site indicate that dissolved petroleum constituents (VOCs) are present at concentrations above the VGES in groundwater collected from MW12-01, -02, -03, -05, -06, -07, and -08. Select compounds were also present above laboratory detection limits but below the VGES in these samples. The highest levels of VOCs were noted in groundwater collected from MW12-01, MW12-02, and MW12-03 which are located at or within approximately 25 feet from the source area.Moderate levelsof VOCs were reported in groundwater collected from downgradient wells MW12-05, -06, and -08. The low levels of VOCs reported in the sample from MW12-07 indicate that the plume dissipates to the west of the source area.No detectable VOCs were reported in groundwater collected from MW12-04. Based on the Contaminant Distribution Map included in Appendix A, the full extent of the dissolved phase contaminant plume has not been fully defined and appears to be predominantly travelling north to northwest towards Rt 116 and the


08/15/12 6 VTDEC Site #2011-4243

aforementioned wetlands. The contaminant plume has been adequately defined towards the southeast due to the initial low levels and subsequent non-detection of VOCs reported in monitoring well MW12-04 at the respective two monitoring events.

6.0 CONCEPTUAL HYDROGEOLOGIC MODEL

6.1 Site Conditions

The Site in the immediate vicinity of the USTs is covered by paved parking and one building, which is one story with no basement. This structure is used as a convenience store and gasoline/diesel station. The topography of the Site is generally flat throughout. The area immediately around the on Site building consists of a paved parking lot. The nearest neighboring building is located approximately 150 feet west of the former USTs across Rt 116. This building is occupied by a new Kinney Drugs. This building is not believed to contain a basement.

6.2 Geology

Surficial deposits in the vicinity of the site are indicated to be either glacial till or recent alluvium. Bedrock is indicated as being dark gray dolomite of the Winooski Formation, abutted by sandstone of the Potsdam Sandstone Formation. This information comes from the Surficial Geolodical Map of the State of Vermont1. Surficial soils encountered during thesupplemental Site Investigation activities consisted primarily of native soils. Native soils were observed to be moderately dense in nature and consist of lean clays mixed with medium sand and gravel.Based on a review of field screening data collected at the Site, saturated soils beneath the Site have low to moderate permeability consisting of sandy lean clay and clayey sand. As of July it appears the top of the water table is located primarily within the clayey sand layer. Soil Boring Logs are included in Appendix B. Bedrock was not observed at the Site to a depth of 11 feet bsg. Drilling refusal did not occur on July 20, 2012 during advancement of the four soil borings.

6.3 Hydrogeology

Depth to groundwater beneath the Site was observed to change slightly from east to west and at a depth ranging from 4.95 to 6.75 feet bsg. Groundwater was documented to flow to the west-northwest under a gradient of approximately 2.0%.

1 Surficial Geologic Map of Vermont


08/15/12 7 VTDEC Site #2011-4243

6.4 Apparent Source of Contamination

Contamination was encountered in soils beneath the Site during the removal of three 10,000-gallon gasoline USTs on September 26-27, 2011. Soils in the vicinity of the removed USTs were reported to have concentration of up to 2,879 ppm when subjected to headspace soils testing using properly calibrated Mini-Rae PID. Saturated soils were encountered in the excavation at a depth of approximately 4 feet below surface grade. Native soils consisted of mostly gray clays. The limits of the contamination were not defined during UST closure assessment dated September 26-27, 2011. No other sources have been identified to date.

6.5 Contaminant Transport

Based on the groundwater analytical data collected to date at the Site, it appears petroleum contamination is predominantly migrating in a general west-northwesterly direction. The previously mentioned small unnamed stream associated with the wetlands appears to flow in the same direction. The contaminant concentrations reported in groundwater in July 2012 suggest a west-northwesterly groundwater flow is present at the Site. Additional monitoring is needed to determine a trend in the groundwater flow direction. The horizontal migration of petroleum contamination towards the west-northwest appears to be travelling within a sandy clay layer, whichis likely where the largest quantity of gasoline contamination is present beneath the Site. Petroleum contamination may extend further towards the west-northwest under Rt 116 and possibly into the surface water in the wetlands area. The full extent of the contaminant plume was not defined to the north/northwest during the supplemental site investigation. Additional monitoring is needed to track the groundwater flow and spatial distribution of contaminants over time.

6.6 Sensitive Receptor Risk Assessment

6.6.1 Buildings in the Vicinity

The nearest neighboring building is located approximately 150 feet west of the former USTs, but is across Rt 116. This building is occupied by a new Kinney Drugs. The convenience store building on-site, which is up-gradient, is not likely to be impacted by the petroleum contamination.

6.6.2 Utility Corridors

Public utilities in the area include telephone, electricity, water, and sewer. Electric and telephone lines are located overhead and at about 100 feet to the west. Water and sewer are obtained from the Town of Hinesburg and are located underground. Bordering the very southern edge of the property are underground natural gas lines along Commerce Street. There


08/15/12 8 VTDEC Site #2011-4243

is a culvert located north of MW12-07, and based on groundwater flow data collected to date the culvert appears to be downgradient of the source area. The discharge from the culvert should be sampled at the next monitoring event to ensure that it is not at risk of contamination. At this time all othernearby utility corridorsare not considered to be at risk of acting as a conduit for the migration of contaminated groundwater from the Site given their location in relation to the documented groundwater flow and the measured depth to groundwater.

6.6.3 Surface Water Bodies

The nearest surface water is an area of wetland and river found to the north of the site by about 200 feet. While no conclusions could be made about contamination levels in surface waters during the supplemental site investigation, testing of these waters at future monitoring events should enable better analysis of the impacts to surface waters.

6.6.4 Water Supplies

The Site and surrounding properties are serviced by the public water system. No supply wells were observed in the immediate vicinity of the site. Information available online via the Vermont Department of Environmental Conservation, Water Supply Division (viewed on line at http://maps.vermont.gov/?site=ANR_wswelldriller ) indicates 18 private wells within a half mile of the site. The nearest well is located approximately 0.13 miles south of the Site on Rte 16, and there is also a supply well at the commercial property to the north of Site, which is located 0.25 miles from the Site. These wells are not believed to be at risk to the subsurface petroleum contamination at this time.

6.7 Impacted Third Parties

Based on the data collected during the supplemental site investigation significant off-site impact to neighboring properties is not likely. Contamination is present at moderate concentrations at the downgradient wells, and the impacts to surface waters will need to be further defined through sampling.

7.0 CONCLUSIONS

1. Based on the results of the Supplemental Site Investigation, KAS concludes that a release of

petroleum has occurred at the Site. The amounts and duration of the release(s) are unknown; however, dissolved phase VOC concentrations are present above enforcement standards and the groundwater beneath the Site has been impacted;

2. Four soil borings were advanced on July 3, 2012downgradient of the source area in order to

further define the contamination plume. Each of these borings were completed as monitoring wells (MW12-05 through MW12-08) on July 3, 2012;


08/15/12 9 VTDEC Site #2011-4243

3. Subsurface sediments encountered in the four soil borings consisted mostly of lean clay and sandy clay with gravel. PID readings above background were observed in soil samples collected from two of the four borings at various depths. The elevated PID readings ranged from 2.5 to 86.0 ppm;

4. A groundwater monitoring event was conducted on July 20, 2012. Groundwater flow was

directed generally to the west-northwest at an approximate hydraulic gradient of 2.0%; 5. Several of the tested compounds via EPA Method 8021B were reported to be above the

VGES in the groundwater sample collected from seven of the eight monitoring wells on July 20, 2012, and two or more of the tested compounds were reported above the laboratory detection limits but below the VGES in the groundwater from these samples as well. The total reported VOC concentrations ranged from 81.1 (MW12-07) to 18,186 (MW12-02) ug/L (ppb).

6. The full extent of the contaminant plume to the north/northwesthas not fully been defined

due to the lack of a surface water sample and monitoring points; and, 7. Based on the supplemental site investigation sensitive receptors including soil and

groundwater have been identified as being potentially at risk to petroleum impact, as well as the nearby wetland and surface waters to the north and the culvert which drains from the area immediately downgradient to the source area.

8.0 RECOMMENDATIONS

Based on the results of the supplemental site investigation conducted at the Site, KAS recommends the implementation of semi-annual groundwater monitoring at the site, including the testing of downgradient surface waters and the discharge from the culvert. At this point the extent of the plume has not been determined and the down-gradient wetland is potentially at risk. KAS recommends that sampling include the collection of groundwater samples from all on Site monitoring wells and additionally the collection of a surface water sample and a sample from the discharge from the culvert.

9.0 REFERENCES

1. Underground Tank Closure Assessment, KAS Inc., Hinesburg Short Stop, Hinesburg,

Vermont, September 28, 2011

2. Google Earth Imagery, 2009

3. Doll, Charles G., ed., 1961, Centennial Geologic Map of Vermont, Vermont Geological Survey.


08/15/12 10 VTDEC Site #2011-4243

4. Doll, Charles G., ed., 1970, Surficial Geologic Map of Vermont, Vermont Geological

Survey.

SITE LOCATION

NorthKAS Number: 409110442

Source: msrmaps.com

Drawing No. 1 Date: 08/20/12Scale: NTS By: LM

Hinesburg Jolley MobilHinesburg, Vermont

Site Location Map

Soil Boring Logs and Monitoring Well Construction Diagrams

Well No: MW12-05Hinesburg Jolley MartHINESBURG, VERMONT

KAS Project #: 409110442 Date Installed: 07/03/12Drilled by : T&K Drilling Drilling Method: Hollowstem Auger

Supervisor: Lauren Morley Boring Diameter: 8.25"Logged by: LM Development Method: Disposable Bailer

Screened Length: 8'Pen/Rec (') Interval (') Soil Characteristics

Grade = 0 Blow Counts PID (ppm) Pavement

0.50 - 0' - 2' LEAN CLAY WITH SAND (CL) CL1.00 - 0.5 Dry, olive gray, homogeneous1.50 Ft<Grade2.002.503.00

3.50

4.00

4.50

5.00

5.50 24"/10" 5'-7' CLAYEY SAND WITH GRAVEL (SC) SC6.00 13-7-13-17 2.5 moist/wet, olive gray, homogeneous 6.50

7.00 6.75

7.50

8.00 7.50

BORING LOG AND WELL CONSTRUCTION DIAGRAM

Well Construction

Gra

phic

Sym

bol

Lette

r Sym

bol

Gra

phic

Sym

bol

8.50

9.00

9.50

10.00

10.50 24"/0" 10'-12' LEAN CLAY WITH SAND (CL) CL11.00 3-3-4-3 86.0 wet, olive gray, homogenous 11.50

12.00

Road Box with Bolt Down Cover, Set in Cement. Locking Plug.Existing Surface. 2" ID, Schedule 40 PVC Riser.Bentonite Seal Placed in Annulus. 2" ID, Schedule 40 PVC, 0.010"-Slotted Well ScreenGrade #1 Silica Sand Pack Placed in Annulus. Plug PointDrill Cuttings Placed in Annulus.

BR BedrockNR - Not Recorded Approximate Water Level During DrillingN/A - Not Applicable Static Water Level

Legend






0.50 - 0' - 2' CLAYEY SAND WITH GRAVEL (SC) SC1.00 - 0.2 Dry, medium brown, homogeneous1.50 Ft<Grade2.002.503.00

3.50

4.00

4.50

5.00

5.50 24"/8" 5'-7' CLAYEY SAND WITH GRAVEL (SC) SC6.00 3-14-9-9 4.9 dry, stratified olive gray and medium brown6.50 6.10

7.00

7.50

8.00


Well Construction

Gra

phic

Sym

bol

Lette

r Sym

bol

Gra

phic

Sym

bol

8.50

9.00

9.50

10.00

10.50 10.00 24"/20" 10'-12' LEAN CLAY (CL) CL11.00 2-2-1-1 0.6 moist/wet, olive gray, homogenous 11.50

12.00



Legend






0.50 - 0' - 2' POORLY GRADED SAND (SP) SP1.00 - 0.2 Dry, medium brown, homogeneous1.50 Ft<Grade2.002.503.00

3.50

4.00

4.50

5.00

5.50 24"/10" 5'-7' LEAN CLAY (CL) CL6.00 3-8-4-4 0.2 moist, light gray, homogeneous 6.50 6.38

7.00

7.50

8.00 7.50


Well Construction

Gra

phic

Sym

bol

Lette

r Sym

bol

Gra

phic

Sym

bol

8.50

9.00

9.50

10.00

10.50 24"/18" 10'-12' LEAN CLAY (CL) CL11.00 3-4-5-4 0.2 wet, olive gray/ light gray, homogenous 11.50

12.00



Legend






0.50 - 0' - 2' POORLY GRADED SAND WITH GRAVEL (SP) SP1.00 - 1.1 Dry, medium brown, homogeneous1.50 Ft<Grade2.002.503.00

3.50

4.00

4.50

5.00

5.50 24"/12" 5'-7' CLAYEY SAND WITH GRAVEL (SC) SC6.00 5.73 6-4-2-2 0.1 moist, medium brown, homogeneous6.50

7.00

7.50

8.00 7.50


Well Construction

Gra

phic

Sym

bol

Lette

r Sym

bol

Gra

phic

Sym

bol

8.50

9.00

9.50

10.00

10.50 24"/20" 10'-12' LEAN CLAY (CL) CL11.00 2-2-3-3 1.8 wet, light gray/ medium brown, homogenous 11.50

12.00



Legend

Liquid Level Monitoring Data

KAS, Inc. Hinesburg Jolley MobilHinesburg, Vermont

Liquid Level Monitoring DataHinesburg Jolley Mobil

Hinesburg, Vermont

Measurement Date: July 20, 2012Top of Depth To Depth To Specific Corrected Corrected

Well I.D. Well Depth Casing Product Water Product Gravity Water Depth Water Tablebtoc Elevation btoc btoc Thickness Of Product Equivalent To Water Elevation

MW12-01 10.00 100.00 - 5.98 - - - - 94.02MW12-02 10.00 100.04 - 5.77 - - - - 94.27MW12-03 10.00 100.28 - 5.89 - - - - 94.39MW12-04 10.00 100.72 - 4.95 - - - - 95.77MW12-05 11.00 100.00 - 6.75 - - - - 93.25MW12-06 11.00 100.12 - 6.10 - - - - 94.02MW12-07 11.00 99.84 - 6.38 - - - - 93.46MW12-08 10.00 99.64 - 5.73 - - - - 93.91

Well I.D. 2/7/2012 7/20/2012

MW12-01 95.39 94.02MW12-02 95.76 94.27MW12-03 95.80 94.39MW12-04 96.68 95.77MW12-05 93.25MW12-06 94.02MW12-07 93.46MW12-08 93.91

All Values Reported in Feet btoc - Below Top of CasingElevations determined relative to top of casing at MW12-01, which was arbitrarily set at 100'Site surveyed by KAS, Inc. on February 7, 2012

HISTORIC GROUNDWATER ELEVATION

VTDEC Site #2011-4243

Groundwater Quality Summary Data

Groundwater Quality Summary


MW12-01

Sample Date 2/8/2012 7/20/2012 Method 8260B 8021B

PARAMETER VGESBenzene 246 256 5Toluene 1,200 313 1000Ethylbenzene 176 132 700Xylenes 17,200 4,930 10000Total BTEX 18,822 5,631 - MTBE ND<200 75.7 401,3,5-Trimethybenzene 1,140 1,0801,2,4-Trimethylbenzene 4,330 3,050Naphthalene 440 377 20Total Targeted VOCs 24,732 10,214 -

Total Petroleum Hydrocarbons 51.4 NT -GW Elevation (ft bg) 94.39 94.02 -

All Values Reported in ug/L (ppb), except TPH-GRO which is reported in mg/L (ppm)All results are from EPA Method 8260BTPH-GRO values are from EPA Method 8015 VGES - Vermont Groundwater Enforcement Standard (February 14, 2005)ND - None detected above sample-specific compound detection limitBold font indicates a detected concentration.Shaded values meet or exceed VGES

350

VTDEC # 2011-4243



MW12-02


PARAMETER VGESBenzene 930 228 5Toluene 3,950 951 1000Ethylbenzene 354 273 700Xylenes 11,700 7,680 10000Total BTEX 16,934 9,132 - MTBE ND<100 30.8 401,3,5-Trimethybenzene 1,420 1,0701,2,4-Trimethylbenzene 4,520 3,400Naphthalene 391 394 20

350Naphthalene 391 394 20n-Propylbenzene 83.0 NT -t-Butanol 1,650 NT -Total Targeted VOCs 24,998 14,027 -



VTDEC # 2011-4243



MW12-03


PARAMETER VGESBenzene 83.5 61.1 5Toluene 878 308 1000Ethylbenzene 213 110 700Xylenes 5,210 2,430 10000Total BTEX 6,384.5 2,909 - MTBE ND<100 14.6 401,3,5-Trimethybenzene 1,200 7001,2,4-Trimethylbenzene 4,050 2,200 350Naphthalene 389 314 20n-Propylbenzene 82.0 NT -Total Targeted VOCs 12,106 6,138 -



VTDEC # 2011-4243



MW12-04


PARAMETER VGESBenzene ND<1.0 ND<1.0 5Toluene ND<1.0 ND<1.0 1000Ethylbenzene ND<1.0 ND<1.0 700Xylenes ND<2.0 ND<2.0 10000Total BTEX ND ND - MTBE ND<2.0 ND<2.0 40Acetone 20.3 NT 7001,3,5-Trimethybenzene ND<2.0 ND<1.01,2,4-Trimethylbenzene 1.8 ND<1.0 350Naphthalene ND<2.0 ND<2.0 20n-Propylbenzene ND<1.0 NT -t-Butanol ND<20 NT -Total Targeted VOCs 22.1 ND -

Total Petroleum Hydrocarbons ND<0.20 NTGW Elevation (ft bg) 96.68 95.77 -


VTDEC # 2011-4243



MW12-05

Sample Date 7/20/2012 Method 8021B

PARAMETER VGESBenzene 374 5Toluene ND<10.0 1000Ethylbenzene 202 700Xylenes 1,310 10000Total BTEX 1,886 - MTBE 57.3 401 3 5-Trimethybenzene 3341,3,5-Trimethybenzene 3341,2,4-Trimethylbenzene 1,340Naphthalene 144 20Total Targeted VOCs 3,761 -GW Elevation (ft bg) 93.25 -


350

VTDEC # 2011-4243



MW12-06


PARAMETER VGESBenzene 152 5Toluene 145 1000Ethylbenzene 193 700Xylenes 4,400 10000Total BTEX 4,890 - MTBE ND<40.0 401 3 5-Trimethybenzene 6701,3,5-Trimethybenzene 6701,2,4-Trimethylbenzene 2,600Naphthalene 307 20Total Targeted VOCs 8,467 -GW Elevation (ft bg) 94.02 -


350

VTDEC # 2011-4243



MW12-07


PARAMETER VGESBenzene 25.8 5Toluene ND<1.0 1000Ethylbenzene 5.6 700Xylenes ND<2.0 10000Total BTEX 31.4 - MTBE 48.2 401 3 5-Trimethybenzene ND<1 01,3,5-Trimethybenzene ND<1.01,2,4-Trimethylbenzene 1.5Naphthalene ND<2.0 20Total Targeted VOCs 81.1 -GW Elevation (ft bg) 93.46 -


350

VTDEC # 2011-4243



MW12-08


PARAMETER VGESBenzene 134 5Toluene ND<10.0 1000Ethylbenzene 57.8 700Xylenes 771 10000Total BTEX 963 - MTBE 86.5 401 3 5-Trimethybenzene 1131,3,5-Trimethybenzene 1131,2,4-Trimethylbenzene 951Naphthalene 165 20Total Targeted VOCs 2,278 -GW Elevation (ft bg) 93.91 -


350

VTDEC # 2011-4243



Date of Sample Collection

PARAMETER Trip Blank MW12-02 Duplicate RPD %MTBE ND<2.0 30.8 ND<40.0 - Benzene 1,080. 228 245 7.2Toluene 3,050. 951 1,020 7.0Ethylbenzene 377. 273 270 -1.1Xylenes ND<2.0 7,680 7,330 -4.71,3,5-Trimethylbenzene ND<1.0 1,070 985 -8.3

Hinesburg Jolley MobilHinesburg, VT

Quality Assurance and Control Summary

7/20/2012

1,2,4-Trimethylbenzene ND<2.0 3,400 3,100 -9.2Naphthalene ND<2.0 394 342 -14.1Total Reported VOCs M8260B 4,507. 14,027 13,292 -5.4

NOTESResults reported above detection limits are indicated in boldEPA Method 8260B used for laboratory analysisAll values reported in ug/l (ppb) unless otherwise notedND<X - Not Detected (Detection Limit)TBQ <X = Trace Below Quantitation Limit

The results of the laboratory analysis of the duplicate sample were analyzed using a relative percent difference (RPD) analysis. The RPD is defined as 100 times the difference in reported concentration between sample and duplicate, divided by the mean of the two samples. A small RPD indicates good correlation between sample and duplicate.

VTDEC # 2011-4243

Groundwater Analytical Report

Laboratory Report

409110442 Hinesburg JolleyPROJECT:

DATE RECEIVED:WORK ORDER:

DATE REPORTED:

100488KAS, IncPO Box 787Williston, VT 05495

Atten: Jeremy Roberts SAMPLER:July 30, 2012

1207-10631

Josh Douglas

July 23, 2012

Reviewed by:

Harry B. Locker, Ph.D.Laboratory Director

Enclosed please find the results of the analyses performed for the samples referenced on the attached chain of custody. All required method quality control elements including instrument calibration were performed in accordance with method requirements and determined to be acceptable unless otherwise noted.

The column labeled Lab/Tech in the accompanying report denotes the laboratory facility where the testing was performed and the technician who conducted the assay. A "W" designates the Williston, VT lab under NELAC certification ELAP 11263; "R" designates the Lebanon, NH facility under certification NH 2037 and “N” the Plattsburgh, NY lab under certification ELAP 11892. “Sub” indicates the testing was performed by a subcontracted laboratory. The accreditation status of the subcontracted lab is referenced in the corresponding NELAC and Qual fields.

The NELAC column also denotes the accreditation status of each laboratory for each reported parameter. “A” indicates the referenced laboratory is NELAC accredited for the parameter reported. “N” indicates the laboratory is not accredited. “U” indicates that NELAC does not offer accreditation for that parameter in that specific matrix. Test results denoted with an “A” meet all National Environmental Laboratory Accreditation Program requirements except where denoted by pertinent data qualifiers. Test results are representative of the samples as they were received at the laboratory

Endyne, Inc. warrants, to the best of its knowledge and belief, the accuracy of the analytical

test results contained in this report, but makes no other warranty, expressed or implied, especially no warranties of merchantability or fitness for a particular purpose.

160 James Brown Dr., Williston, VT 05495Ph 802-879-4333 Fax 802-879-7103

ELAP 11263

www.endynelabs.com

NH203756 Etna Road, Lebanon, NH 03766 Ph 603-678-4891 Fax 603-678-4893

Laboratory Report

KAS, Inc

Page 2 of 3

CLIENT:PROJECT: 409110442 Hinesburg Jolley

WORK ORDER:DATE RECEIVED:

1207-1063107/23/2012

7/30/2012REPORT DATE:

001 Date Sampled: 7/20/12Site: MW12-01 7/25/12 RBFWAnalysis Date:10:29QualNelacUnitResultParameterQualNelacUnitResultParameter

TEST METHOD: EPA 8021B

75.7 NMethyl-t-butyl ether (MTBE) ug/L 256 NBenzene ug/L313 NToluene ug/L 132 NEthylbenzene ug/L

4,930 NXylenes, Total ug/L 1,080 N1,3,5-Trimethylbenzene ug/L3,050 N1,2,4-Trimethylbenzene ug/L 377 NNaphthalene ug/L

86 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks



30.8 NMethyl-t-butyl ether (MTBE) ug/L 228 NBenzene ug/L951 NToluene ug/L 273 NEthylbenzene ug/L

7,680 NXylenes, Total ug/L 1,070 N1,3,5-Trimethylbenzene ug/L3,400 N1,2,4-Trimethylbenzene ug/L 394 NNaphthalene ug/L




14.6 NMethyl-t-butyl ether (MTBE) ug/L 61.1 NBenzene ug/L308 NToluene ug/L 110 NEthylbenzene ug/L

2,430 NXylenes, Total ug/L 700 N1,3,5-Trimethylbenzene ug/L2,200 N1,2,4-Trimethylbenzene ug/L 314 NNaphthalene ug/L




< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L

89 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks



57.3 NMethyl-t-butyl ether (MTBE) ug/L 374 NBenzene ug/L< 10.0 NToluene ug/L 202 NEthylbenzene ug/L1,310 NXylenes, Total ug/L 334 N1,3,5-Trimethylbenzene ug/L1,340 N1,2,4-Trimethylbenzene ug/L 144 NNaphthalene ug/L100 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks

Laboratory Report

KAS, Inc

Page 3 of 3

CLIENT:PROJECT: 409110442 Hinesburg Jolley

WORK ORDER:DATE RECEIVED:

1207-1063107/23/2012

7/30/2012REPORT DATE:



< 40.0 NMethyl-t-butyl ether (MTBE) ug/L 152 NBenzene ug/L145 NToluene ug/L 193 NEthylbenzene ug/L

4,400 NXylenes, Total ug/L 670 N1,3,5-Trimethylbenzene ug/L2,600 N1,2,4-Trimethylbenzene ug/L 307 NNaphthalene ug/L




48.2 NMethyl-t-butyl ether (MTBE) ug/L 25.8 NBenzene ug/L< 1.0 NToluene ug/L 5.6 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L1.5 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L85 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks



86.5 NMethyl-t-butyl ether (MTBE) ug/L 134 NBenzene ug/L< 10.0 NToluene ug/L 57.8 NEthylbenzene ug/L

771 NXylenes, Total ug/L 113 N1,3,5-Trimethylbenzene ug/L951 N1,2,4-Trimethylbenzene ug/L 165 NNaphthalene ug/L92 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks

009 Date Sampled: 7/20/12Site: Trip Blank 7/25/12 RBFWAnalysis Date:08:15QualNelacUnitResultParameterQualNelacUnitResultParameter


< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L

89 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks

010 Date Sampled: 7/20/12Site: Duplicate (MW12-02) 7/25/12 RBFWAnalysis Date:09:55QualNelacUnitResultParameterQualNelacUnitResultParameter


< 40.0 NMethyl-t-butyl ether (MTBE) ug/L 245 NBenzene ug/L1,020 NToluene ug/L 270 NEthylbenzene ug/L7,330 NXylenes, Total ug/L 985 N1,3,5-Trimethylbenzene ug/L3,100 N1,2,4-Trimethylbenzene ug/L 342 NNaphthalene ug/L


supplemental site investigation report

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