HAZARD RANKING SYSTEM (HRS) DOCUMENTATION RECORD COVER SHEET

Name of Site : Alamo Contaminated Ground Water

EPA ID No. : TNN000410203

Contact Persons

Documentation Record : John Nol e n , Remedial Project Manager U.S. Environmental Protection Agency, Region 4 61 Forsyth Street, S.W., 11 th Floor Atlanta, Georgia 30303 (404) 562

- 8923

Jennifer Wendel, National Priorities List Coordinator U.S. Environmental Protection Agency, Region 4 61 Forsyth Street, S.W., 1 1 th Floor Atlanta, Georgia 30303 (404) 562

- 8799

Quinn Kelley, Environmental Scientist Tetra Tech EM, Inc. 1955 Evergreen Boulevard, Ste. 300 Duluth, Georgia 30096 (678) 775

- 3101

Pathways, Components, or Th reats Not Scored

The surface water migration, soil exposure, and air migration pathways were not scored in this Hazard Ranking System documentation record because they are not expected to significantly contribute to the overall site score.1 HAZARD R ANKING SYSTEM (HRS) DOCUMENTATION RECORD

Name of Site: Alamo Contaminated Ground Water

EPA Region: 4

Date Prepared: March 201 1

Street Address of Site*: South Bells Street

City, County, State, Zip: Alamo

, Crockett County, Tennessee 38001

Gener al Location in the State: Western portion of state

Topographic Map: Alamo

, Tennessee 19 64

Latitude: 35° 47' 02. 95 " North

Longitude: 89° 07' 0 4

. 88 " West

The coordinates above for the Alamo Contaminated Ground Water site were measured from the City of Alamo Water Department facility (Ref. 4 ).

* The street address, coordinates, and contaminant locations presented in this HRS documentation record identify the general area where the site is located. They represent one or more locations the U.S. Env ironmental Protection Agency (EPA) considers part of the site based on the screening information EPA used to evaluate the site for National Priorities List (NPL) listing. EPA lists national priorities among the known “releases or threatened releases” of h azardous substances; thus, the focus is on the release, and not on precisely delineated boundaries. A site is defined as an area where a hazardous substance has been “deposited, stored, placed, or otherwise come to be located.” Generally, HRS scoring and the subsequent listing of a release represent the initial determination that a certain area may need to be addressed under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Accordingly, EPA contemplates that the prelimin ary description of facility boundaries at the time of scoring will be refined as more information is developed about where the contamination has come to be located.

Pathway Pathway Score Ground Water Migration 100.00 Surface Water Migration NS
Soil Ex posure NS Air Migration NS
HRS SITE SCORE 50.00

Note s :

HRS Hazard Ranking System NS Not scored2 WORKSHEET FOR COMPUTING HRS SITE SCORE

S Pathway S 2 Pathway
Ground Water Migration Pathway Score (S gw ) 100 .00 10,000
Surface Water Migration Pathwa y Score (S sw ) NS NS
Soil Exposure Pathway Score (S s ) NS NS
Air Migration Pathway Score (S a ) NS NS

S 2 gw + S 2

sw + S 2

s + S 2

a 10,000 (S 2 gw + S 2

sw + S 2

s + S 2

a ) / 4 2,500 √ (S 2 gw + S 2

sw + S 2

s + S 2

a ) / 4 50.00

Note:

NS = Not scored3 Table 3

- 1

-- Ground Water Migration Pathway Scoresheet Aquifer Evaluated: Memphis Sand

Factor Categories and Factors Maximum Value Value Assigned

Likelihood of Release to an Aquifer: 1. Observed Release 550 550 2. Potential to Release: 2a. Containment 10 NS 2b. Net Precipitation 10 NS 2c. Depth to Aquifer 5 NS 2d. Travel Time 35 NS 2e. Potential to Release [lines 2a(2b + 2c + 2d)] 500 NS 3. Likelihood of Release (higher of lines 1 and 2e) 550 550 Waste Characteristics: 4. Toxicity/Mobility ( a) 10,000.0 5. Hazardous Waste Quantity (a) 100 6. Waste Characteristics 100 32 .0 Targets: 7. Nearest Well 50 50.0 8. Population: 8a. Level I Concentrations (b) 22,921.8 8b. Level II Concentrations (b) 0.00 8c. Potential Contaminatio n (b) NS 8d. Population (lines 8a + 8b + 8c) (b) 22,921.8 9. Resources 5 0 .0 10. Wellhead Protection Area 20 20.0 11. Targets (lines 7 + 8d + 9 + 10) (b) 22, 991

. 8 Ground Water Migration Score for an Aquifer: 12. Aquifer Score [(lines 3 x 6 x 11)/82,500] c 100 100 .00 Ground Water Migration Pathway Score: 13. Pathway Score (S gw ), (highest value from line 12 for all aquifers

e valuated) c 100 100 .00

Notes:

NS = Not scored

a = Maximum value applies to waste characteristics category
b
= Maximum value not applicable

c = Do not round to nearest integerCROCKETT COUNTY, TENNESSEE2010-09-28 S:\GIS_Workspace\TTEMI-05-003-0101_Alamo_Groundwater_HRS\Figures\GIS\MXDs\Site Location Maps\AGW SITE LOC MAP 9-28-10.mxd TTEMI-GA ingrid.tobar

FIGURE 1 SITE LOCATION ALAMO CONTAMINATED GROUND WATER SITE, ALAMO CROCKETT COUNTY, TENNESSEE TDD No.TTEMI-05-003-0101 Note: The approximate extent of the ground water plume is defined by permanent monitoring well locations AG18, AG08, AG17, and City of Alamo municipal well No. 2 location (AG02). (Refs. 7, Enclosure 3, p. E3-2; 8, p. 12).

Map Source: USGS 7.5 Minute Series Topographic Quadrangle Maps: Maury City, TN 1981 and Alamo, TN 1981.

United States Environmental Protection Agency LEGEND
Approximate Extent of Alamo Ground Water Plume in May 2010

0 1,500 750 Feet 1:18,000Alamo Mills The Crockett Times

Former Tucker Automotive Former Volunteer Circuits E. Church St. Dry Cleaners & Laundry

N. Johnson St. Dry Cleaners

Alamo Water Department Ward's Dry Cleaners

S Bells St E Church St W Church St N Bells St

S Mill St S Burns St E Park St E Main St W Main St

S Johnson St

W Vine St W Park St S Branch St

W Koonce St Mulberry St E Elm St N Mill St

S Mulberry St

E Vine St

Brigance St

Cherry St S Cherry St N Johnson St E Cherry St

N Cherry St

E Cedar St S Poplar St

Hays St N Burns St

E Factory St N Locust St N Mulberry St N Branch St

E Park Ln Williams Cir

Lyndon St Cypress Rd W Tanner St S Court St N Court St

E Vine St2010-09-16 \GIS_Workspace\TTEMI-05-003-0101_Alamo_Groundwater_HRS\Figures\GIS\MXDs\Site Layout Maps\AGW SITE LAYOUT MAP 9-16-10.mxd TTEMI-GA ingrid.tobar

FIGURE 2 SITE LAYOUT ALAMO CONTAMINATED GROUND WATER SITE, ALAMO CROCKETT COUNTY, TENNESSEE TDD No.TTEMI-05-003-0101

Business Location Source: Reference 76.

Map Source: HSIP Gold Dataset, 2007. I 3 Imagery Prime World 2D, 2010.

United States Environmental Protection Agency LEGEND
Exisiting Structure

Former Structure
Major Road

Street

0 500 250 Feet 1:6,000CT-06-GP

CT-07-GP CT-03-GP AG06-0510-MW

AG20-0510-MW

AG18-0510-MW

AG17-0510-MW AG15-0510-MW AG09-0510-MW AG08-0510-MW

AG18-0510-MWD

CT-AWD2-PW

CT-AWD4-PW CT-AWD2D-PW

AG04-0510-MS AG03-0510-MS

AG02-0510-MS

AG01-0510-MSD

AG01-0510-MS

CT-AWD1-PW E Church St

S Bells St W Church St N Bells St

E Park St S Mill St W Main St

E Main St

W Park St S Burns St

S Johnson St S Branch St E Elm St N Mill St

Brigance St

S Cherry St

Cherry St

E Cedar St N Johnson St

N Burns St N Locust St N Branch St N Cherry St

E Park Ln S Court St N Court St N Cherry St2010-09-17 \GIS_Workspace\TTEMI-05-003-0101_Alamo_Groundwater_HRS\Figures\GIS\MXDs\Site Layout Maps\AGW SOURCE SAMPLING LOCATION MAP 9-17-10.mxd TTEMI-GA ingrid.tobar

ALAMO CONTAMINATED GROUND WATER SITE, ALAMO CROCKETT COUNTY, TENNESSEE TDD No.TTEMI-05-003-0101 Map Source: Refs. 7, Enclosure 2, p. E2-1; 7, Enclosure 5, p. E5-19; 11, Figure 7, p. 15. HSIP Gold Dataset, 2007. I 3 Imagery Prime World 2D, 2010.

United States Environmental Protection Agency Notes: Alamo Contaminated Ground Water Site Alamo Water Department Crockett Times Duplicate Geoprobe Sample Municipal Sample Monitoring Well
Potable Well AG
AWD CT
D GP MS
MW
PW

0 300 150 Feet 1:3,600

FIGURE 3 SAMPLING LOCATIONS LEGEND January 2004 Crockett Times Site Inspection Geoprobe Source Sample Geoprobe Background Sample May 2010 Expanded Site Inspection Monitoring Well Source Sample Monitoring Well Background Sample Alamo Water Department Municipal Wells Municipal Well Source Sample Municipal Well Background Sample Sampled in January 2004 Sampled in May 2010 Approximate Extent of Alamo Ground Water Plume in May 2010 CT AG7 REFERENCES

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.

3. Tetra Tech EM Inc. (Tetra Tech). 4

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. Scale 1:24,000. 1 Map.

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on December 21, 2010

. 1 Page. Accessed On

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.

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. Alamo Contaminated Ground w ater
, Alamo

, Crockett County, Tennessee

. Enclosures: Soil Boring/Well Logs, Well Survey, Figures

, Tables, Field Logbook Notes, and Field Sample Collect ion Sheets. August 27, 2010

. 118 Pages.

8. Tennessee Department of Environment and Conservation (TDEC)

. Expanded Site Investigation Narrative Report. Alamo Contaminated Ground w ater Plume Site, Alamo, Crockett County, Tennessee. September 15, 2010. 505 Pages.

9. EPA Region 4 Science and Ecosystem Support Division (SESD) . Final Analytical Report. Alamo Contaminated Groundwater, Project Number 10

- 0422. July 1, 2010. 114 Pages.

10. United States Geological Survey (USGS) . Reconnaissance Investigation of Vo latile and Semivolatile Organic Compounds in the Memphis Aquifer at Alamo, Crockett County, Tennessee. By Susan S. Hutson and Connor J. Haugh. Open

- File Report 90

- 580. 1992. 20 Pages.

11. TN & Associates, Inc

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14. ATC. Report of Findings from Additional Geoprobe Investigation, Volunteer Circuits Site. Prepared for TDEC. August 18, 2000. 20 Pages.

15. ATC. Report of Findings from Third Geoprobe Invest igation, Volunteer Circuits Site. Prepared for TDEC. October 12, 2000. 18 Pages.8 16. TDEC Division of Superfund. Phone Memo to File. Subject: Volunteer Circuits, Date of Air Stripper Installation. October 21, 1992. 1 Page.

17. USGS. “ Geology and Ground

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- Resources Investigations Report 88

- 4182. 1990. 34 Pages.

18. TDEC Division of Water Supply

. Letter Regarding Wellhead Protection Plan Approval. From : Thom as A. Moss, Wellhead Protection Coordinator, Ground W ater Management Section . To: John Gorman, Alamo Water Department. Attachment: Wellhead Protection Program Approval Certificate. August 21, 1997. 2 Pages.

19. EPA Region 4 SESD. Field Branches Quality System and Technical Procedure for Groundwater Sampling, Number SESDPROC

- 301

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.

20. Tetra Tech. Project Note to File. Subject: Data Review, Validation, and Verification Conducted at the SESD, Analytical Support Branch. January 6, 200 9 . 1 Page.

21. Tetra Tech. Record of Telephone Conversation. S ubject: Definitions of Minimum Reporting Limit, Minimum Quantitation Limit, Contract Required Quantitation Limit, and Sample Quantitation Limit. Between Shanna Davis, Environmental Scientist, and Charlie Appleby, Quality Assurance Section, Management and Technical Services Branch, EPA Region 4 SESD . July 9, 2008. 1 Page.

22. TDEC. Preliminary Assessment for The Crockett Times Site , Alamo, Tennessee. February 2 8, 2001. 2 4 Pages.

23. USGS. Ground

- Water Resources of Western Tennessee . By Franc i s G. Wells. Water

- Supply Paper 656. Prepared in Cooperation with the Tennessee Division of Geology. 1933. 339 Pages.

24. USGS. “ General Geology of the Mississippi Embayment .” By E.M. Cushing, E.H. Boswell, and R.L. Hosman. Professional Paper 448

- B

. 1964

. 34 Pages

.

25. USGS. “ Geology and Hydrology of the Claiborne Group in Western Tennessee .” By Gerald K. Moore. Water

- Supply Paper 1809

- F . 1965. 5 7 Pages.

26. USGS. “ Geology and Ground

- Water Resources of the Cockfield Formation in Western Tennessee. ” By W.S. Parks a nd J.K. Carmichael. Water

- Resources Investigations Report 88

- 4181. 1990. 22 Pages.

27. USGS. “ Geology and Ground

- Water Resources of the Fort Pillow Sand in Western Tennessee. ” By W.S. Parks and J.K. Carmichael. Water

- Resources Investigations Report 89

- 4 120. 1989. 25 Pages.

28. EPA Center for Environmental Research Information. Guides to Pollution Prevention: The Printed Circuit Board Manufacturing Industry. June 1990. 83 Pages.

29. Tetra Tech. Telecon to File. Subject: Alamo Water Department Well No. 1 Service Information. Between Quinn Kelley, Environmental Scientist and John Gorman, Operator, Alamo Water Department. November 1, 2010. 1 Page.

30. TDEC. Tennessee 106 Groundwater Work Program Supplemental : 1988 Carryover Proposal #2 (Alamo). 1988. 5 Pa ges.

31. Environmental Science Corp. (ESE). Letter Regarding Third Quarter VOC Samples. From : Sharon McNutt, Client Services Manager

. T o : John Perry, Alamo Water and Sewer Commission. August 28, 1991. 17 Pages.9 32. TDEC. Trip Report, Verification of Surface Drainage, Municipal Well Locations, and Site History. February 14, 1992. 1 Page.

33. Tetra Tech. Project Note to File with Attachment. Subject: Summary of J

- Qualified Data. August 18, 2010. 2 Pages.

34. EPA Office of Emergency and Remedial Response. Usi ng Qualified Data to Document an Observed Release and Observed Contamination. Quick Reference Fact Sheet EPA

- 540

- F

- 94

- 028. November 1996. 18 Pages.

35. Tetra Tech. Project Note to File with Attachment. Subject: Rationales for Data Qualifiers. March 26, 2008. 4 Pages.

36. Tetra Tech. Project Note to File with Attachment. Subject: May 2010 Chain

- of

- Custody Records for the Alamo Contaminated Ground Water Site ESI. Attachment: EPA Organic Traffic Reports for Case No. 40118, Signed Laboratory Copies. Augus t 23, 2010. 1 2 Pages.

37. EPA. CLP, SOW for Organics Analysis, Multi

- Media, Multi

- Concentration, SOM01.1, May 2005, and Summary of Changes SOM01.1 to SOM01.2, April 2007. 747 Pages. Accessed On

- line at http://www.epa.gov/superfund/programs/clp/som1.htm

.

38. TDEC. Site Evaluation Quality Assurance Project Plan, Alamo Contaminated Groundwater Site. Prepared for EPA Region 4. April 22, 2010

. 15 Pages.

39. USGS. 7.5 Minute Series Topographic Qu adrangle Map of Tennessee: Alamo 1964. 1 Map.

40. TDEC. Logbook Notes for Municipal Well Sampling from May 2010 ESI Sampling Event. May 13, 2010. 5 Pages.

41. TDEC. Preliminary Assessment for Volunteer Circuits Site, Alamo, Crockett County, Tennessee. Apri l 1992. 32 Pages.

42. TN&A. Logbook Notes from The Crockett Times SI Sampling Event. From July 24, 2003 to January 22, 2004. 16 Pages.

43. TDEC. Prescreening Investigation for Tucker Automotive, Alamo, Tennessee. July 12, 2000. 23 Pages.

44. TDEC. Prescreen ing Investigation for North Johnson Street, Alamo, Tennessee. August 27, 2004. 47 Pages.

45. TDEC. Prescreening Investigation for East Church Street Site, Alamo, Tennessee. September 10, 2004. 40 Pages.

46. TDEC. Pre

- CERCLIS Screening Assessment Report for Alamo Mills, Alamo, Crockett County, Tennessee. December 21, 2007. 16 Pages.

47. TDEC. Memorandum with Attachments . Subject: Alamo Wellhead Protection Area/Volunteer Circuits. From : Tom Moss, Ground Water Section Manager, Division of Water Supply. To : Ron Sells, Jackson Manager, Division of Superfund. June 14, 1995. 20 Pages.

48. Tennessee Department of Health and Environment (TDHE). Letter Regarding the Alamo Water System with Attachments. From : Edmund O’Neill, Manager, Jackson Field Office, Division of Water Supply. To : The Honorable Tommy Green, Mayor, City of Alamo. Attachments: Laboratory Data Sheets. October 3, 1988. 21 Pages.10 49. TDHE. Environmental Laboratories , Organic Analysis. Data Sheets for Well No. 1, the Clearwell, the Well Oil, and the Drainage Ditch. October and November 1988. 7 Pages.

50. ESE. Laboratory Reports for VOC Analysis of Alamo Water Supply Wells. 1989 to 1990. 44 Pages.

51. ESE. Letter Regarding Fourth Quarter VOC Samples. From : Sharon Northcutt , Client Services Manager. To : John Perry, Alamo Water and Sewer Department . November 27, 1991. 5 Pages.

52. TDEC Division of Superfund. Memo to File with Attachment. Subject: Contaminant Trend in A.W.D. Well #1. Attachment: Table and Chart. April 6, 1992. 2 Pages.

53. EPA Region 4 SESD. Environmental Investigations Standard Operating Procedures and Quality Assurance Manual. November 2001. 413 Pages.

54. TDEC Division of Water Supply. Memorandum. Subject: Alamo Wellfields. From : Tom Moss, Ground Water Management Section. To : Bre nda Shaw, TN&A. June 12, 2003. 1 Page.

55. Tetra Tech. Telecon to File. Subject: Alamo Water Department Well Survey. Between Quinn Kelley, Environmental Scientist and John Gorman, Operator, Alamo Water Department. September 17, 2010. 1 Page.

56. Tetra Tec h. Telecon to File. Subject: County

- Wide Utility District Well Survey. Between Quinn Kelley, Environmental Scientist and Jere Kail, General Manager, County

- Wide Utility District. September 17, 2010. 1 Page.

57. Agency for Toxic Substances and Disease Reg istry (ATSDR). ToxFAQs for Tetrachloroethylene

. U.S. Department of Health and Human Services, Public Health Service. September 1997. 2 Pages.

58. TDEC. Project Note to File

. Subject: Ward’s Dry Cleaners, Alamo, Tennessee

. September 2 , 2010

. 1 Page.

59. E PA Office of Research and Development. Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Ground Water, EPA/600/R

- 98/128. September 1998. 248 Pages.

60. EPA Envirofacts Warehouse. Angelica Uniform Group. Facility Detail Repo rt (Last Updated August 20, 2010), RCRAInfo (Last Updated August 20, 2010), and Enforcement and Compliance History Online (Last Updated August 9, 2010). Accessed August 20, 2010 and September 2, 2010. 6 Pages. Accessed On

- line at : http://iaspub.epa.gov/enviro/fii_query_dtl.disp_program_facility?p_registry_id=110004992937

.

61. Angelica Corporation. Angelica Corporate History. Accessed September 2, 2010. 1 Page. Accessed On

- line at : http://www.angelica.com/corporate

- history.html

.

62. EPA Envirofacts Warehouse. Brown Chevrolet Inc. Facility Detail Report (Last Updated August 20, 2010), R CRAInfo (Last Updated August 20, 2010), and Enforcement and Compliance History Online (Last Updated August 9, 2010). Accessed August 20, 2010 and September 2, 2010. 6 Pages. Accessed On

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.

63. EPA Envirofacts Warehouse. Partners Pallets. Facility Detail Report (Last Updated August 20, 2010), RCRAInfo (Last Updated August 20, 2010), and Enforcement and Compliance History Online (Last Updated August 9, 2010). Accessed August 20, 2010 and September 2, 2010. 6 Pages. Accessed On

- line at : http://iaspub.epa.gov/enviro/fii_query_dtl.disp_program_facility?p_registry_id=110004967304

.11 64. EPA Envirofacts Warehouse. Skelton Trucking/SE. Facility Detail Report (Last Updated August 20, 2010), RCRAInfo (Last Updated August 20, 2010), and Enforcement and Compliance History Online (Last Updated August 9, 2010). Accessed August 20, 2010 and September 2, 2010. 6 Pages. Accessed On

- line at : http://iaspub.epa.gov/enviro/fii_query_dtl.disp_program_facility?p_registry_id=110007860742

.

65. EPA Office of Solid Waste and Emergency Response. Quick Reference Fact Sheet. Multi

- Media, Multi

- Concentration, Organic A nalytical Service for Superfund (OLM04.3). August 2003. 4 Pages.

66. EPA. Contract Laboratory Program Organic Traffic Report and Chain of Custody Record. Case No. 32529. January 2004. 3 Pages.

67. EPA Region 4 SESD. Analytical Support Branch Laboratory Op erations and Quality Assurance Manual. Effective Date January 13, 2003. 222. Pages.

68. Alamo Water & Sewer Division . Wellhead Protection Plan

, PWSID# TN0000005

. Technical Assistance Provided By Tennessee Association of Utility Districts. Update January 2010. 24 Pages.

69. TDEC Division of Superfund. Trip Report. Purpose of Visit: Meet with PRP to get an idea of potential source locations at the Volunteer Circuits site. Superfund Personnel Present: James Morrison. Individuals Contacted: Benny McGee and Vincent McGee. October 23, 1992. 1 Page.

70. TDEC. Teleconference . Subject: Dates of Operation, Manufacturing Processes, and Ownership of Volunteer Circuits in Alamo . Between C.L. Powers and Clay Ackerman

. March 30 , 1992. 1 Page.

71. TDEC. Teleconference . Subject: Ownership and Dates of Operation of Volunteer Circuits in Alamo. Between C.L. Powers and Alainee McGee, Sales Representative for Volunteer Circuits. March 26, 1992. 1 Page.

72. Tetra Tech. Project Note to File with Attachments. Subject: Parce l Information and Map for Property where ATC Collected a Ground Water Sample in September 2000. Attachments: Parcel Information and Map. September 15, 2010. 5 Pages.

73. TDEC. Memo to File. Subject: Discussions with TDSWM and David Bartholomew Regarding the Crockett Times Site. Prepared by Ron Sells. February 1, 2001. 1 Page.

74. Tetra Tech. Project Note to File with Attachment. Subject: 2004 Crockett Times Site Inspection Contract Laboratory Program Form I Data Sheets. Attachment: Volatile Organics An alysis Form I Data Sheets. September 17, 2010. 29 Pages.

75. U.S. Census Bureau. State and County QuickFacts. Crockett County, Tennessee. Accessed September 20, 2010. 2 Pages. Accessed On

- line at : http://quickfacts.census.gov/qfd/states/47/47033.html

.

76. TDEC. Project Note to File. Subject: Possible Sources of Volatile Organic Compound Contamination in Ground Water Underlying the City of Alamo, Crockett County, Tennessee. September 17, 2010. 1 Page.

77. TDEC Division of Water Supply. Tennessee Source Water Assessment Program Submittal. Accessed September 20, 2010. 67 Pages. Accessed On

- line at : http://www.ten nessee.gov/environment/dws/pdf/tswafinl.pdf

.

78. EPA. Generic Organic Traffic Report and Chain of Custody Record. Case No. 32529. January 2004. 2 Pages.12 79. Tetra Tech. Project Note to File with Attachment. Subject: Alamo May 2010 Expanded Site Inspectio n Contract Laboratory Program Form I Data Sheets. Attachment: Volatile Organics Analysis Form I Data Sheets. September 24, 2010. 65 Pages.

80. EPA Region 4 SESD. Field Branches Quality System and Technical Procedure Guidance Document for Design and Instal lation of Monitoring Wells, Number SESDGUID

- 101

- R0. Effective Date: February 18, 2008. 33 Pages. Accessed On

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- Installation

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- Monitoring

- Wells.pdf

.13 

### SITE DESCRIPTION

The Alamo Contaminated Ground Water (ACGW) site is located in Alamo, Crockett County, Tennessee (Ref s

. 4; 6) (see Figure 1 of this Hazard Ranking System [HRS] documentation record). More specifically, the geographic coordinates as measured from the City of Alamo Water Department facility are latitude 35° 47' 02. 95 " north and longitude 89° 07' 04.88 " west (Ref

. 4 ). The site consists of a contaminated ground water plume with no identified source underlying the City of Alamo (the City) (Ref. 8 , p. 3 ). The EPA identification number as recorded in the Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) database is TNN000410203 (Ref. 5 ). Land uses surrounding the ACGW site are predomina n tly residential and mixed commercial (Ref. 6 ) (see Figure 2 of this HRS documentation record)

. The approximate extent of the ground water plume is defined by permanent monitoring well locations AG18, AG08 , AG17, and City of Alamo municipal well No. 2 location ( AG0 2 ) (Refs. 7, Enclosure 3 , p. E 3

- 1 ; 8 , p. 12 ) (see Figure 3 of this HRS documentation record).

One source has been identified for the ACGW site : Source No. 1, source type “other” ground water plume with no identified source ( Refs. 3; 7, Enclosure 3 , p. E 3

- 1 ; 8 , p. 3 ). Volatile organic compounds (VOC) have been documented in Source No. 1 (see Section 2.2.1, Source No. 1). G round water comprising the ACGW site contains 1,1

- dichloroethene ( DCE ) ; 1,2

- dichloroethane ( DCA ) ; tetrachloroethene ( PCE ) ; 1,1,1

- trichloroethane ( TCA ) ; and trichloroethene ( TCE ) (Ref. 8, p p . 12 , 13 , Appendix E, pp. E

- 33, E

- 35, E

- 39 )

. While there are multiple possible current and former sources of VOCs that have been identifi ed in the vicinity of the plume, due to likely commingling of possible multiple releases over time, the contamination in the ground water plume cannot be attributed to any particular source.

PREVIOUS INVESTIGATIONS

Ground water samples collected from t he City of Alamo’s municipal wells in 1988 and 1989 revealed VOC contamination in municipal well No. 1 , including but not limited to 1,1

- DCE; 1,1,1

- TCA; and TCE (Refs. 48, pp. 1 through 4; 49, pp. 1 through 4; 50, pp. 1 through 24)

. VOCs were also detecte d in well Nos. 2 and 3 (Refs. 48, pp. 5 through 8; 50, pp. 25 through 38). In a sample collected by the Tennessee Department of Health and Environment ( TD HE ) (currently the Tennessee Department of Environment and Conservation [TDEC ] ) on September 22, 1988

, TCE was detected at a concentration of 97.9 micrograms per liter (μg/L) in municipal well No. 1 (Ref. 48, p. 4). Another sample from September 1988 contained TCE at a concentration of about 113 μg/L (Refs. 10, p. 3; 52)

. Following the release of these sample results, use of the City ’s municipal well No. 1 was immediately discontinued (Ref. 1 0 , p. 3). As an interim remedial measure, the City resumed pumping well No. 1, although not for distribution, and discharged the water to a drainage ditch (Ref s

. 16 ; 29; 30 , p. 1). The City continued discharging water pumped from well No. 1 to a drainage ditch until July 2, 1991 when the City of Alamo installed an air stripper (Refs. 16; 29)

. At this time, municipal well No. 1 was put back into service and all City of Alamo municipal wells were monitored for VOC concentrations on a quarterly basis (Refs. 16; 29; 31, p. i; 32; 51, p. i). In 1991, VOC s were still present in two of the City’s four municipal wells (Ref s

. 31 , p p

. 3, 9 , 13 ; 51, p. 3 ). City of Alamo muni cipal well No. 1 is still in service at the time of this HRS documentation record (Ref. 29).

After the discovery of VOC contamination in the City of Alamo’s municipal wells, the TDHE began investigating the possible sources of the contamination. In 1989 , the U.S. Geological Survey (USGS), in conjunction with TD HE Division of Superfund , conducted an investigation of the Memphis Sand aquifer at Alamo (Ref. 10, p. 1)

. The City of Alamo’s municipal wells are screened in the Memphis Sand aquifer (Ref. 55)

. The study employed soil

- gas analyses and sampling of all four municipal wells (Ref. 10, p. 1)

. S oil

- gas was analyzed at 42 sampling points on and near the wells in the City’s wellfield south of West Main Street (Ref s

. 7, Enclosure 3, p. E3

- 1; 10, p p

. 2, 3 )

. The sampling points were located at a former industrial site, hydraulically downgradient of a n underground gasoline storage tank, adjacent to a vehicle maintenance building, and near the City of Alamo wellfield (Ref. 1 0 , p p

. 10, 11). The industrial si te was the former location of Volunteer Circuits, a circuit board manufacturing facility , where organic solvents had been used in the cleaning of electronic components (Ref s

. 10, p. 3; 28, p. 5; 32 ; 69 ). Soil

- gas samples14 were collected at a depth of 3.5 f eet below land surface ( bls ) and were analyzed for VOCs. These analyses provided an initial estimate of the direction, areal extent, and chemical composition of the contaminant plume (Ref. 10, p. 10). TCE was detected in 13 of the 42 soil

- gas samples, wi th the highest concentrations detected at or near the former location of Volunteer Circuits

, at a maximum concentration of 30 micrograms per kilogram (μg/kg) (Ref. 10, pp. 10, 11)

. However, it should be noted that soil

- gas contamination could indicate con tamination in surface soils, gases migrating upward from the contaminated ground water plume, or both.

Ground water samples collected during the USGS and TDHE investigation from municipal well No. 1 contained the highest concentrations of TCE (45 μg/L) ; 1,1,

- DCE (32 μg/L) ; PCE (1.2 μg/L) ; and 1,1,1

- TCA ( 38 μg/L). Well No. 2 also contained TCE ( 0 .7 μg/L) ; 1,1

- DCE (0.9 μg/L) ; and 1,1,1

- TCA (1.3 μg/L). VOCs were not detected in the other two municipal wells at the time of the investigation (Ref. 1 0

, p. 8)

.

Volunteer Circuits

A preliminary assessment (PA) was completed for Volunteer Circuits in April 1992 by TDEC Division of Superfund (Ref. 41, p. 1)

. Volunteer Circuits had manufactured printed circuit boards for the electronic s industry from 1973 to 197 5 (Ref s . 41, p. 2 ; 70; 71 ). Printed circuit board manufacturing involves use of various cleaners including 1,1,1

- TCA and TCE (Ref. 28, p. 5). This assessment concluded that Volunteer Circuits posed a potential threat to the public and environment, and re commended further investigation (Ref. 41, pp. 7, 8).

Between July and November 1992, TDEC Division of Superfund

, conducted sampling activities for a site inspection ( SI ) at the Volunteer Circuits property (Ref. 12, pp. 1, 8)

. The SI included collection of soil samples at and in the vicinity of Volunteer Circuits and ground water samples from the City of Alamo’s municipal wells (Ref. 12, pp. 8, 16). Soil samples were collected from two areas, a former TCE drum storage area and a film developer equipment area, where spent TCE had been dumped when servicing the f ilm developer (Ref s . 1 2 , p p

. 6, 7 ; 69 )

. Neither of these two areas had institutional containment structures or liners (Ref s . 12, p p. 6, 7 ; 69 ). The areas of VOC soil contamination identified duri ng the TDEC SI corresponded to the areas identified during the USGS soil

- gas investigation (Ref. 12, p. 19). VOCs detected in the City of Alamo ’s municipal well Nos. 1

, 2 , and 3 includ ed 1,1

- DCE (up to 3 5 μg/L); PCE (up to 0.7 μg/L); 1,1,1

- TCA (up to 31 μ g/L); and TCE (up to 45 μg/L) (Ref. 12, pp. 16, 17) . It was concluded that the VOC contamination in the municipal wells , excluding PCE, was likely partially attributable to Volunteer Circuits (Ref. 12, p p . 20 , 21 )

.

In November and December 1999, ATC Asso ciates, Inc. (ATC), on behalf of TDEC, conducted a n investigation at the Volunteer Circuits property (Ref. 13, p. 3 ) . ATC advanced 10 soil borings to depths ranging from 44 to 55 feet b l s . Soil borings were screened with an organic vapor analyzer, and th e depth intervals with the highest readings within each boring were sampled for VOC analysis (Ref. 13, p. 3 )

. VOCs including 1,1

- DCE (up to 0.111 parts per million [ ppm ] ) ; cis

- 1,2

- DCE (0.014 ppm); PCE (0.006 ppm) ; 1,1,1

- TCA (up to 0.174 ppm) ; and TCE (up to 0.073 ppm) were detected in four soil borings ranging in depth from 5 to 25 feet b l s (Ref. 13, p. 6 )

. In addition to soil sampling, ATC collected ground water samples from each of the 10 borings (Ref. 13, p. 3 ). VOCs were detected in ground water coll ected from nine of the 10 locations, with the highest concentrations detected at the north western corner of the Volunteer Circuits property. At this location, 1,1

- DCE was detected at a concentration of 233 parts per billion ( ppb ) ; 1,1,1

- TCA was detected a t a concentration of 231 ppb ; and TCE was detected at a concentration of 187 ppb (Ref. 13 , pp. 7

, 8 ).

In June 2000, ATC conducted a second investigation of the area surrounding the Volunteer Circuits property
, during which 10 additional borings were advan ced to depths ranging from 48 to 64 feet b l s

. Only ground water was sampled and analyzed for VOCs during this investigation (Ref. 14, p. 3 ). The highest VOC concentrations were detected in boring locations northwest and side gradient of Volunteer Circuit s , including 1,1

- DCE at 159 ppb ; 1,1,1

- TCA at 125 ppb ; and TCE at 31 ppb (Ref. 1 4 , pp. 5

, 6 )

. PCE was detected in ground water samples collected from one location east and upgradient of Volunteer15 Circuits, near a dry cleaner ( B

- 19 at 45 ppb ) and one locat ion south west and downgradient of Volunteer Circuits, near the Alamo Water Department ( B

- 13 at 20 ppb ) (Ref. 14, pp. 5

, 6 ).

In September 2000, ATC conducted a third investigation of the area surrounding the Volunteer Circuits property at locations identif ied as potential areas of concern. ATC personnel advanced eight borings at depths ranging from 46 to 60 feet b l s where ground water was sampled and analyzed for VOCs (Ref. 15,
p. 3 ) . One ground water sample collected north west of Volunteer Circuits , near The Crockett Times building, contained 1,1

- DCE (87 ppb); 1,1,1

- TCA (25 ppb); and TCE (6 ppb) (Refs. 6, pp. 20, 21, 23; 15, pp. 5, 6) . PCE was detected in one ground water sample collected east of the Volunteer Circuits property

, near a service station, a t a concentration of 98 ppb (Ref s

. 1 5, pp. 5

, 6 ; 72, pp. 1, 2, 4 ).

The Crockett Times

Between January and February 2001, TDEC completed a PA for The Crockett Times

. The Crockett Times is a local newspaper located at 46 West Main Street (Ref. 22, p. 1) . The newspaper was established in 1933 and the building that houses the newspaper office was built that same year. The newspaper is printed weekly, and until the 1960 s , was printed at the Alamo office (Ref s . 22, p. 2 ; 73 ). Printing operations are now s ubcontracted to The Dyersburg Gazette in nearby Dyersburg, Tennessee, but the newspaper office remains in Alamo (Ref s

. 11, p. 2; 22, p. 2). PCE; 1,1,1

- TCA; and TCE are associated with newspaper printing (Refs. 11, p. 5; 22, p. 5)

. Because VOC contaminati on was detected in ground water downgradient of T he Crockett Times property during the investigations at Volunteer Circuits, The Crockett Times property was recommended for further investigation (Ref. 22, p. 4, 10, 11).

In January 2004, T N & Associates , Inc. (TN & A), on behalf of the EPA, conducted an SI at The Crockett Times in Alamo, Tennessee (Ref. 11, pp. 1, 2) . In 1988, chlorinated solvents were detected in Alamo municipal well No. 1, located about 400 feet south of The Crockett Times office (Ref. 11, p. 2)

. At that time, t he contamination was attributed to the Volunteer Circuits site, but TDEC considered The Crockett Times a potential contributor to the ground water contamination based on typical newspaper printing activities

, including use of ink s containing solvents and use of solvents to clean the printing presses (Ref. 11, pp. 2, 5). Waste storage and disposal practices employed by The Crockett Times during printing operations are unknown (Ref. 11, p. 5).

During the SI, TN&A collected 14 surf ace soil, five temporary monitoring well ground water, and three municipal well ground water samples (Ref. 11, p. 14) . Carbon disulfide was the only VOC detected in surface soil samples (Ref. 11, pp. 15, 23)

. VOCs were detected in three of the temporary monitoring well ground water samples, including 1,2

- DCA at (13 J [estimated] μg/L) ; 1,1

- DCE (up to 6J [estimated] μg/L) ; PCE (up to 240 μg/L) ; and TCE (4J [estimated] μg/L) (Ref. 11, p. 31). VOCs including 1,1

- DCE (up to 14 A [average] μg/L); PCE (up to 13 A [average] μg/L); 1,1,1

- TCA (up to 3.4 A [average] μg/L); and TCE (up to 4.4 A [average] μg/L), were also detected in the three municipal well ground water samples (Ref. 11, p. 30) (see Table 2 of this HRS documentation record)

.

Alamo Contaminated Ground Wa ter Site

In May 2010, TDEC, on behalf of EPA, conducted an expanded site inspection (ESI) at the ACGW site. During the ESI, 14 permanent monitoring wells were installed and sampled in the City of Alamo (Ref. 7, Enclosure 1, Enclosure 3, p. E3

- 1)

. A tota l of 20 soil samples were collected from the borings between 0 and 23 feet bls (Refs. 7, Enclosure 6 ; 8, p p

. 10, 13 ) . No site

- related VOCs were detected in any of the soil borings (Ref. 8 , p. 13 ) . Ground water samples were also collected from the City of Alamo’s four municipal wells (Refs. 7, Enclosures 5 and 6; 8 , p .12 ; 40) . Ground water samples collected from the permanent monitoring wells contained 1,2

- DCA (4.0 μg/L) and PCE (up to 1.2 μg/L) (Ref. 9, pp. 91, 96 )

. Ground water samples collected from the City’s municipal wells contained 1,1

- DCE (up to 3.9 μg/L) ; PCE (up to 18 μg/L) ; 1,1,1

- TCA (up to 0.55J μg/L) ; and TCE (up to 1.8 μg/L) (Ref. 9, pp. 34, 35, 37, 38, 39) (see Table 4 of this HRS documentation record)

. PCE was detected above its EPA maxi mum contaminant level (MCL) of 5 μg/L in municipal ground water well samples AG01

- 0510

- MS (16 μg/L), AG01

- 0510

- MSD (16 μg/L), AG02

- 0510

- MS (18 μg/L), and AG03

- 0510

- MS (9.9 μg/L) (Refs. 2, p. BII

11; 8, p. 12). TCE was detected at concentrations exceeding its EPA cancer risk screening concentration16 of 0.21 μg/L in municipal ground water well samples AG01

- 0510

- MS (1.7 μg/L), AG01

- 0510

- MSD (1.8 μg/L), and AG03

- 0510

- MS (1.1J μg/L) (Refs. 2, p. BI,B2

- 1; 8, p. 12).Source No. 1

17 Source Characterization 2.2 SOURCE CHARACTERIZATION

2.2.1 S OURCE IDENTIFICATION

Number of source : 1

Name of source : Contaminated Ground Water Plume

Source Type : Other

– Ground Water Plume with No Identified Source

Description and Location of Source (with reference to a map of site):

The ACGW site consists of a contaminated ground water plume with no identified source underlying the City of Alamo (Refs. 7, Enclosure 3 , p. E 3

- 2 ; 8 , p. 12 ). The approximate extent of the ground water plume is defined by permanent monitoring well locations AG18, AG08, AG17, an d City of Alamo municipal well No. 2 location ( AG0 2 , AWD #2 ) (Refs. 7 , Enclosure 3 , pp. E 3

- 1, E 3

- 2 ; 8 , p. 1 9 ) (see Figure 3 of this HRS documentation record).

Ground water samples collected from the City of Alamo’s municipal wells in 1988 and 1989 reveale d 1,1

- DCE ; 1,1,1

- TCA ; and TCE contamination in municipal well No. 1 (Refs. 48, pp. 1 through 4; 49, pp. 1 , 2 ; 50, pp. 1 through 24). The highest TCE concentration was detected in a sample collected by TDHE (currently TDEC) in September 1988 at about 113 μ g/L (Refs. 10, p. 3; 52). Following the release of these sample results, use of the City of Alamo ’s municipal well No. 1 was immediately discontinued (Ref. 10, p. 3). As an interim remedial measure, the City resumed pumping well No. 1, although not for d istribution, and discharged the water to a drainage ditch ( Refs. 16; 30, p. 1 ). The City continued discharging water pumped from well No. 1 to a drainage ditch until July 2, 1991 when the City of Alamo installed an air stripper (Refs. 16; 29). At this ti me, municipal well No. 1 was put back into service and all City of Alamo municipal wells were monitored for VOC concentrations on a regular basis (Refs. 29; 31, p. i; 51, p. i). City of Alamo municipal well No. 1 is still in service at the time of this HR S documentation record (Ref. 29).

Source samples collected from Source No. 1 during the January 2004 Crockett Times SI and May 2010 ACGW site ESI contained 1,1

- DCE; 1,2

- DCA; PCE; 1,1,1

- TCA; and TCE (Refs. 7, Enclosure 3 , p. E 3

- 2 ; 8 , p. 12 ; 11, pp. 30, 31 ) (see Table 1 of this HRS documentation record).Source No. 1

18 Source Characterization 2.2.2 HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE

During the EPA January 2004 Crockett Times SI, ground water samples were collected from the City of Alamo’s municipal wells, as well as from tempo rary monitoring wells. During the EPA May 2010 ACGW site ESI, the City of Alamo’s municipal wells were once again sampled. Also during the ESI

, permanent monitoring wells were installed and sampled in the City of Alamo. Table 1 presents the ground water wells and hazardous substances associated with Source No. 1, a ground water plume with no identified source . For more detailed analytical results document ing the ground water plume , see Section 3.1.1 of this HRS documentation record

.

TABLE 1: Source No. 1 Ground Water Wells and Associated Hazardous Substances

Well ID Sample ID Hazardous Substances References City of Alamo Municipal Wells

No. 1 CT

- AWD1

- PW AG01

- 0510

- MS AG01

- 0510

- MSD 1,1

- DCE PCE 1,1,1

- TCA TCE 9, pp. 32, 33, 34, 35; 11, Appendix B, p. B

- 1

No. 2 CT

- AWD2

- PW CT

- AWD2D

- PW AG02

- 0510

- MS 1,1

- DCE PCE 1,1,1

- TCA TCE 9, p. 37; 11, Appendix B, pp. B

- 2, B

- 3

No. 3 AG03

- 0510

- MS 1,1

- DCE TCE 9, pp. 38, 39

Temporary Monitoring Wells

CT

- 03

- GP CT

- 03

- GP PCE 11, Appendix B, p. B

- 62
CT

- 07

- GP CT

- 07

- GP PCE 11, Appendix B, p. B

- 66 Permanent Monitoring Wells

AG08 AG08

- 0510

- MW PCE 9, p. 51
AG09 AG09

- 0510

- MW PCE 9, p. 55
AG15 AG15

- 0510

- MW PCE 9, p. 83
AG17 AG17

- 0510

- MW 1,2

- DCA 9, p. 91

AG18 AG18

- 0510

- MW AG18

- 0510

- MWD PCE 9, pp. 96, 98

Notes:

AG Alamo Conta minated Ground Water AWD Alamo Water Department CT Crockett Times D Duplicate DCA Dichloroethane DCE Dichloroethene GP Geoprobe ID Identification MS Municipal well sample MW Monitoring well sample No. Number PCE Tetrachloroethene PW Potable well TCA Trichl oroethane TCE TrichloroetheneSource No. 1

19 Source Characterization 2.2.3 HAZARDOUS SUBSTANCES AVAILABLE TO A PATHWAY

Samples collected from Source No. 1 contained 1,1

- DCE; 1,2

- DCA ; PCE; 1,1,1

- TCA ; and TCE . Source No. 1 consists of a contaminated ground water plume with no identified sourc e underlying the City of Alamo (Ref s

. 7

, Enclosure 3 , p. E 3

- 2; 8 , p. 12 ) (also see Table s 2 and 4 of this HRS documentation record). Analytical results for ground water samples collected from monitoring wells installed in the City of Alamo, as well as the City of Alamo’s municipal wells

, indicate that a release of hazardous substances has occurred to the ground water migration pathway as documented in Section 3. 1.1 of this HRS documentation record. During the EPA May 2010 ACGW site ESI

, no liners were obs erved during permanent monitoring well installation and sampling activities (Ref. 7

, Enclosure 1 ). Therefore, a containment factor value of 10, as noted in Table 2 , was assigned for the ground water migration pathway (Ref. 1, Section 3.1.2.1, Table 3

- 2).

TABLE 2 : Containment Factors for Source No. 1

Containment Description Containment Factor Value References
Gas release to air NS NA

Particulate release to air NS NA
Release to ground water: No liner ; evidence of migration 10 1, Section 3.1.2.1, Table 3

- 2; 7, Enclosure 1 ; see also Section 3.1.1 of this HRS documentation record.
Release via overland migration and/or flood NS NA

Notes:

NA Not applicable NS Not scoredSource No. 1

20 Source Characterization 2.4.2.1 HAZARDOUS WASTE QUANTITY

2.4.2.1.1 Hazardous Constituent Quantity

The i nformation available is not sufficient to evaluate Tier A, hazardous constituent quantity, as required by Reference 1, Section 2.4.2.1.1.

Hazardous Constituent Quantity Assigned Value: NA

2.4.2.1.2 Hazardous Wastestream Quantity

The information availab le is not sufficient to evaluate Tier B, hazardous wastestream quantity, as required by Reference 1, Section 2.4.2.1.2.

Hazardous Wastestream Quantity Assigned Value: NA

2.4.2.1.3 Volume

Based on sampling data, a contaminated ground water plume with no identified source underlies the City of Al a mo, Tennes s ee. The vertical and horizontal extent of ground water contamination have not been identified. Therefore, for Source No. 1

, a value of greater than zero has been assigned for the source hazardous was te quantity (HWQ) value for volume (Ref. 1, Section 2.4.2.1.3 )

.
Volume Assigned Value: > 0

2.4.2.1.4 Area

Tier D is not evaluated for source type “other” (Ref. 1, Section 2.4.2.1.4 ).

Area Assigned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity V alue

Source No. 1 is assigned a source HWQ value of greater than zero, but undetermined (Ref. 1, Sec tion 2.4.2.1.5).

Source HWQ Value: >021 Source Characterization SUMMARY OF SOURCE DESCRIPTIONS

TABLE 3 : Summary of Source Descriptions

Source No. Source Hazardous Waste Quan tity Value Source Hazardous Constituent Quantity Complete? (Yes/No) Containment Factor Value by Pathway

Ground Water (Ref. 1, Table 3

- 2) Surface Water Overland/ Flood (Ref. 1, Table 4

- 2) Air

Gas (Ref. 1, Table 6

- 3) Particulate (Ref. 1, Table 6

- 9 )

1 >0 No 10 NS NS NS

Notes:

> Greater than NS Not scored

Total Source Hazardous Waste Quantity Value: >0.

Other Possible Sources

**•** Volunteer Circuits: Volunteer Circuits manufactured printed circuit boards for the electronics industry from 1973 to 1975 (Refs. 41, p. 2; 71). Printed circuit board manufacturing involves use of various cleaners including 1,1,1

- TCA and TCE (Ref. 28, p. 5). Between 1992 and 2000, TDEC conducted several investigations of the Volunteer Circuits property, as well as surro unding properties. Soil and ground water samples collected during these investigations contained VOCs including 1,1

- DCE; cis

- 1,2

- DCE; PCE; 1,1,1

- TCA; and TCE. VOCs detected in the City of Alamo’s municipal well Nos. 1, 2, and 3 included 1,1

- DCE (up to 35 μg/L); PCE (up to 0.7 μg/L); 1,1,1

- TCA (up to 31 μg/L); and TCE (up to 45 μg/L) (Ref. 12, pp. 16, 17). It was concluded that the VOC contamination, excluding PCE, in the municipal wells was likely partially attributable to Volunteer Circuits (Ref. 12, pp . 20, 21).

**•** The Crockett Times : The Crockett Times is a local newspaper located at 46 West Main Street (Ref. 22, p. 1). The newspaper was established in 1933 and the building that houses the newspaper office was built that same year. PCE; 1,1,1

- TCA; a nd TCE are associated with newspaper printing (Refs. 11, p. 5; 22, p. 5). In 1988, chlorinated solvents were detected in Alamo municipal well No. 1, located about 400 feet south of The Crockett Times office (Ref. 11, p. 2). TDEC considered The Crockett T imes a potential contributor to the ground water contamination based on typical newspaper printing activities, including use of inks containing solvents and use of solvents to clean the printing presses (Ref. 11, pp. 2, 5). In January 2004, TN&A, on behal f of the EPA, conducted an SI at The Crockett Times (Ref. 11, pp. 1, 2). Carbon disulfide was the only VOC detected in surface soil samples collected during the SI (Ref. 11, pp. 15, 23). Also during the SI, VOCs

, including 1,2

- DCA; 1,1

- DCE; PCE; 1,1,1

- TC A; and TCE, were detected in temporary monitoring well ground water samples and in the C ity of Alamo’s municipal wells (Ref. 11, pp. 30, 31)

, but they could not be specifically linked to operations at The Crockett Times

.

**•** North Johnson Street Dry Cleaner s : In July and August 2004, TDEC conducted a prescreening investigation at the property located at 18 North Johnson Street, Alamo, Tennessee (Ref. 44, p p

. 1 , 3, 9 ) . From about 1941 to about 1973, th is property was used as a dry cleaning business, and

was at one time known as Alamo Dry Cleaners (Ref. 44, p . 2) . Two soil samples were collected and analyzed for VOCs, one near the back wall and one near the side wall of the building (Ref. 44, p. 4) . PCE and TCE were not detected in either sample (Ref. 44, p p. 5, 43, 44 , 46, 47 )

. At the22 Source Characterization time of the investigation, no wells were present that would allow access to the ground water for sampling; therefore, no ground water samples were collected (Ref. 44, p. 4). During the EPA May 2010 ACGW site ESI

, permanent m onitoring well AG08 was installed in the parking lot immediately in front of 18 North Johnson Street (Ref s . 7, Enclosure 3, p. E3

- 1; 8, p. 19; 44, p p

. 14 , 15 ). The ground water sample collected from this well, AG08

- 0510

- MW, contained PCE (0.67 μg/L) (Ref. 9, p. 51) . PCE is a common solvent used in the dry cleaning industry (Ref. 57, p. 1)

.

**•** Ward’s Dry Cleaner s : Ward’s Dry Cleaners (Ward’s) is located at 807 East Main Street (Ref s . 6,
p p

. 5, 31 , 38 ; 8, p. 19; 58 ). It is currently in operation; therefore, according to regulations, TDEC cannot investigate the facility. Ward’s is not part of TDEC’s dry cleaner program and it does not currently perform any dry cleaning on the premises , although at one time it did (Ref. 58)

. During the EPA May 2010 ACGW site ESI, permanent monitoring well AG18 was installed in the alley adjacent to Ward’s (Refs. 6, p. 38 ; 7, Enclosure 3, p. E3

- 1 ; 8, p. 19 ). The ground water samples collected from this well, AG18

- 0510

- MW and AG18

- 0510

- MWD, contained PCE at concentrations of 1 .2 μg/L and 1.1 μg/L, respectively (Ref. 9, pp. 96, 98)

.23 GW

- Likelihood of Release 3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 GENERAL CONSIDERATIONS

Ground Water Migration Pathway Description

Regional Geology

The ACGW site is located in the central portion of Crockett County o n the Mississippi Embayment of the Coastal Plain physiographic province (Ref. 10, p. 3). More specifically, the ACGW site is located in the North Central Plateau, which is predominantly underlain by sandy material from the Wilcox and Claiborne deposits. The topography is characterized by extensive terrace and loess deposits (Ref. 24, p. B24 ). The Mississippi Embayment is comprised of Paleozoic rocks that are filled with unconsolidated sediments of Mesozoic and Cenozoic age

― primarily sand, clay, silt, chalk, gravel, and lignite. Due to the westward dip of the strata, these sediments are as much as 3,000 feet thick near the axis, but their thickness decreases eastward to about 2,500 to 2,600 feet in the vicinity of the ACGW site (Ref. 10, p. 3). The elevation of the ACGW site is approximately 360 to 375 feet amsl (Ref. 39). The geology in the vicinity of the ACGW site may include, in descending stratigraphic order, some or all of the following units: alluvial deposits of Holocene and Pleistocene age; loess of Pleistocene age; fluvial (terrace) deposits of Pleistocene and Pliocene age; the Claiborne Group composed of the Jackson and Cockfield Formation of late Eocene age; the Cook Mountain Formation of middle Eocene age; th e Memphis Sand Formation (500

- foot sand) of early Eocene age; the Wilcox Group composed of the Flour Island Formation and Fort Pillow Sand (1,400

- foot sand) of upper Paleocene age; the Old Breastworks Formation of middle Paleocene age; the Midway Group com posed of the Porters Creek Clay of middle Paleocene age; and the Clayton Formation of lower Paleocene age (Ref. 17, p. 4).

The surface sediments (<100 feet) in the vi cinity of the ACGW site consist of either fluvial deposits or the Cockfield Formation. W here present, the Jackson Formation overlies the Cockfield Formation, but because of similarities in lithology, the Jackson and Cockfield Formations cannot be reliably subdivided (Ref. 26, pp. 4, 7). For the purposes of this HRS evaluation , these sediment s will be referred to as the upper Claiborne Group. Fluvial deposits are characterized by sand, gravel, minor clay, and ferruginous sandstone (Ref. 10, p. 4). The Cockfield Formation commonly consists of clay and silt in the upper part and sand in the lo wer part, but locally, the upper part contains thick sand beds and the lower part contains thick clay and silt beds that are difficult to distinguish from the underlying Cook Mountain Formation (Ref. 26, p. 5). Fluvial deposits range from 0 to 100 feet th ick

, and the Cockfield Formation ranges from 0 to 270 feet thick (Ref. 10, p. 4).

The Cook Mountain Formation underlies the Cockfield Formation, and generally consists of clay and silt. However, in the vicinity of the ACGW site, it may consist predomina n tly of fine sand due to a possible facies change at the time of sediment deposition, post

- depositional erosion, or local faulting of the strata (Ref. 10, p. 4). Thickness ranges from 40 to 200 feet, but averages about 70 feet. According to driller logs, this formation is thin or absent at the City of Alamo wellfield. However, a clay deposit, which may be the Cook Mountain Formation at a depth of 120 to 140 f ee t bls (247 to 227 feet amsl), was recorded in a drillers log 1 mile northwest of Alamo, (Ref. 10 , p. 4).

The Cook Mountain Formation is underlain by the Memphis Sand Formation, which consists of very fine to very coarse sand that includes subordinate lenses or beds of carbonaceous and lignitic clay and silt at various horizons; thin lenses of lign ite also occur locally (Ref. 17, p. 5). The Memphis Sand includes strata equivalent to, in ascending order, the Tallahatta Formation, Winona Sand, Zilpha Clay, Sparta Sand of Mississippi, Car r izo Sand, Cane River Formation, and Sparta Sand of Arkansas (Re f. 17, p. 5). The Memphis Sand ranges from 0 to about 900 feet thick. In the vicinity of the ACGW site, the Memphis Sand is approximately 500 feet thick (Ref. 17, pp. 5, 6). According to lithologic logs from the May 2010 sampling event, the Memphis Sand Formation is first encountered at about 20 to 40 feet bls (347 to 327 feet amsl) (Ref. 7, Enclosure 1, Enclosure 2, Enclosure 4, p. E4

- 1).24 GW

- Likelihood of Release Underlying the Memphis Sand Formation is the Flour Island Formation. This formation ranges in thickness from 0 to 310 feet and consists of predominantly clay and silt, but also contains sand, and lignite (Ref. 17, p. 4). Where present, the formation acts as a confining unit between the Memphis Sand and the Fort Pillow Sand (Ref. 17, p. 4). The Flour Island Formation is estimated to be approximately 540 feet bls (173 feet below mean sea level [bmsl]) in the vicinity of the ACGW site (Ref. 17, p. 6).

All targets evaluated for the ACGW site are in the Memphis Sand aquifer; therefore, formations/aquifers below the Memph is Sand are not discussed further

.
Regional Aquifer Description:

Overview narrative

– Surficial aquifers in western Tennessee are located in alluvium and fluvial deposits comprised of sand, gravel, silt, clay and ferruginous sandstone (Ref. 27, p. 4) . Available data suggest that the majority of the surficial aquifer is found in the sand and gravel deposits of the Mississippi River alluvial plain , which is part of the Quaternary System . These water bearing zones provide water to farm and domestic wel ls in rural areas (Ref. 17, p. 4). Where present, the Cook Mountain Formation provides a lower confining unit for the Cockfield Formation, separating the Cockfield aquifer from the Memphis Sand aquifer. The Memphis Sand aquifer is the primary source of w ater for residents in western Tennessee (Refs. 10, p. 1; 26, p. 7).

Surficial aquifer

– In western Tennessee, the surficial aquifer is not well defined within the alluvium and fluvial deposits. Consequently, local imper v ious layers form small basins of p erched water (Ref. 23, p. 41). Where present, the Jackson Formation overlies the Cockfield Formation, but because of similarities in lithology, the Jackson and Cockfield Formations cannot be reliably subdivided (Ref. 26, pp. 4, 7). The Cockfield aquifer is generally unconfined and is comprised of saturated beds or lenses of sand. Recharge to this aquifer is by precipitation on sparse outcrops or downward migration of water from the overlying fluvial deposits (Ref. 26, p. 7). The Cockfield aquifer provid es small to moderate quantities of water for several public and industrial supply wells, as well as domestic and farm wells in western Tennessee (Ref. 26, p. 14). The potentiometric surface within the upper Claiborne Group is complex due to large differen ces in the altitude of the uplands of the Gulf Coastal Plain and the lowlands of the Mississippi Alluvial Plain. Seasonal fluctuations also add to the complexity

, but ground water flow typically conforms to topography (Ref. 26, pp. 7, 9). In 1985 the gro und water elevation of the upper Claiborne Group, in the vicinity of the A CGW site, ranged from 325 to 350 f ee t amsl (Ref. 26, p. 8).

Confining Unit

– The Cook Mountain Formation is comprised of clay, sand, and silt

, and averages 70 feet in thickness. Wh ere present, it acts as the lower confining unit of the Cockfield aquifer (Ref. 26, pp. 4, 7). According to driller’s log of the City of Alamo wellfield, the Cook Mountain Formation is not recognizable (Ref s

. 10, p. 4; 47, pp. 14, 15 ). In the ACGW site v icinity, the Cook Mountain Formation may be thin and/or sandy, or displaced by faults leaving the Cockfield and Memphis aquifer in direct hydraulic connection (Refs. 7, Enclosure 1; 10, p. 4; 17, pp. 7, 9).

Memphis Sand aquifer

– The Memphis Sand aquifer is the primary source of water for residents in western Tennessee. It is a thick deposit of water

- bearing sand that includes subordinate lenses or beds of clay and silt at various horizons. It is estimated to contain approximately 170 trillion gallons of water (Refs. 10, p

. 1; 17, p. 5; 25, p. F17). Recharge to the aquifer generally occurs from precipitation along the broad outcrop belt across western Tennessee and downward infiltration of water from the overlying fluvial and alluvium deposits (Ref. 17, p. 7). Static water levels at the City of Alamo public supply wells, screened in the Memphis Sand aquifer, range from 39 to 49 feet bls, or from 328 to 318 feet amsl. Total depths of these wells range from 125.8 to 213 feet bls, or from 224.2 to 137 feet amsl (Refs. 10, pp. 6, 10; 39; 47, pp. 10 through 14; 55 ). Due to the thin or absent Cook Mountain formation, the Memphis Sand aquifer is generally unconfined in the vicinity of the A CGW site (Ref. 10, p. 4). Ground water flow in the unconfined portion of the Memphis Sand aquifer is westward, which generally conforms to the topography as well as the westward dip of the Claiborne Group strata. Ground water flow in the confined portion of the Memphis Sand aquifer is west

- southwest, following the westerly dip of the Claiborne Group strata (Refs. 7, Enclosure 3, p. E3

- 2; 10, p. 5; 17, p. 7).25 GW

- Likelihood of Release Site Geology/Aquifer Description

According to lithologic logs from permanent monitoring wells installed during the EPA May 2010 ESI, the ACGW site is underlain, in desc ending stratigraphic order, by silty to sandy clay; and sand with clay lenses (Ref. 7, Enclosure 1). According to a USGS study conducted in 1988 and 1989, VOCs were detected in the two shallowest wells located in the City of Alamo wellfield (Ref. 10, p. 1 0). The detection of these compounds, as well as the lack of evidence supporting the presence of the Cook Mountain Formation in the vicinity of the A CGW site, indicate that the silty and sandy clay present in the vicinity of the ACGW site is not a compete nt confining or semi

- confining unit (Refs. 17, pp. 7, 9; 10, pp. 4, 10; 26, pp. 4, 7).

Surface sediments are composed of undifferentiated clastic and siliciclastic sediments. Neither the Cockfield nor the Cook Mountain Formation appears to be present in the vicinity of the ACGW site (Ref. 7, Enclosure 1). Typically, the Cook Mountain Formation is a minimum of 40 feet thick and serves as the upper confining unit of the Memphis Sand aquifer (Ref. 10, p. 4). As evident in the lithologic logs generated by EPA, the sediment at and above the water table consists of sand and clay lenses. It is unclear whether this zone is part of the Cook Mountain Formation that has undergone a facies change as the result of sediment deposition, post

- depositional erosion, or local faulting of the strata (Refs. 7, Enclosure 1; 10, p. 4). Due to the presence of sand and clay lenses, as well as a possible facies change, the Cook Mountain Formation becomes difficult to distinguish between the lower Cockfield and the upper Memphis Sand (Ref. 10, p. 4).

Static water level measured in wells installed during the EPA May 2010 ACGW site ESI range from 37.80 to 53.84 feet bls, or 317.08 to 303.48 feet amsl, which coincides with water levels in the City of Alamo wellfield. This suggests that the newly installed permanent monitoring wells are completed and withdraw water from within the Memphis Sand aquifer (Refs. 7, Enclosure 1, Enclosure 2, Enclosure 3 , p. E 3

- 2, Enclosure 4, p. E4

- 1 ; 10, p. 5). This concurrence indicates that the confi ning layer (Cook Mountain Formation) between the Cockfield aquifer and the Memphis Sand aquifer is thin or absent in the site vicin i ty
, allowing water to more readily migrate to the Memphis aquifer (Refs. 7, Enclosure 1, Enclosure 2, Enclosure 3, p. E3

- 2, Enclosure 4, p. E4

- 1; 10, p p

. 4, 5 )

.
Depths of the permanent monitoring wells installed during the EPA May 2010 ACGW site ESI range from 85.83 to 111.80 feet bls, or 275.34 to 243.77 feet amsl. Logs of these monitoring wells display water levels indi cating that ground water flows in a westerly direction toward the City of Alamo wellfield (Ref. 7, Enclosure 1, Enclosure 2, Enclosure 3, p. E3

- 2).

Aquifer Interconnection

In w estern Tennessee, the surficial aquifer is not well defined

, but is generally located in the Cockfield formation

. Regionally, t he surficial aquifer is comprised of sand, silt, clay and lignite making it quite similar to the Memphis Sand

, which consists of sand, silt, clay, and minor lignite (Ref. 10, p. 4). The Cook Mountain Forma tion by and large consists of clay and silt and generally acts as a confining unit (between the Cockfield and Memphis Sand)

, but can locally consist of fine grain sand and clay lenses consequently diminishing the ability to serve as a competent confining u nit (Ref. 17, p. 4). Conditions for downward leakage are particularly favorable where the Cook Mountain Formation is thin or sandy or where faults have displaced the Cook Mountain Formation leaving the Cockfield and Memphis Sand aquifer s in direct hydraul ic connection (Ref. 17, p. 7, 9). A review of the lithologic logs from the May 2010 ESI indicates that ground water is first encountered approximately 317 to 303.5 feet amsl, which coincides with water levels in the City of Alamo wellfield. Th is suggests that the newly installed permanent monitoring wells are completed within the Memphis Sand aquifer

. The logs further suggest that the surficial aquifer may not be present in the vicinity of the ACGW site (Refs. 7, Enclosure 1, Enclosure 2, Enclosure 3, p. E3

- 2, Enclosure 4, p. E4

- 1; 10, p. 5).26 GW

- Likelihood of Release Aquifer Discontinuities

The Memphis Sand provides water for most public and industrial supplies in the western part of Tennessee and outcrops east of Crockett County. T he Memphis Sand aquifer is considered to be continuous within the 4

- mile radius of the ACGW site (Ref. 17, p p

. 4, 6)

.
SUMMARY OF AQUIFER BEING EVALUATED

TABLE 4 : Summary of Aquifer Being Evaluated

Aquifer Name Is Aquifer Interconnected with Upper Aquifer within 2

Miles? (Yes/No/NA) Is Aquifer Co ntinuous within 4

- mile TDL?

(Yes/No) Is Aquifer Karst? (Yes/No) References

Memphis Sand Yes 1 Yes No 7, Enclosure 1; 10, p. 4; 17, pp. 7, 9

Notes:

1 If/where the overlying surficial aquifer is present TDL Target distance limit27 GW

- Likelihood of Release 3.1 LIKELIHOOD OF RELEAS E

3.1.1 OBSERVED RELEASE

Aquifer Being Evaluated: Memphis Sand

- Hazardous Substances in Release: 1,1

- DCE ; 1,2

- DCA ; PCE; 1,1,1

- TCA ; and TCE

Chemical Analysis

Since 1988, VOCs have been documented in ground water underlying the City of Alamo and in Ala mo’s municipal drinking water wells (Refs. 8, p p

. 5, 12; 10, pp. 1, 3; 48, pp. 1 through 4; 49, pp. 1 through 4)

. Source No. 1 is a ground water plume with no identified source (Refs. 7, Enclosure 3 , pp. E 3

- 1, E 3

- 2; 8

, p. 12 ) (see Figure 3 and Section 2.2 .1 of this HRS documentation record).

EPA January 2004 Crockett Times Site Inspection

Background Samples

The background ground water samples listed in Table 5 were collected during the EPA January 2004 Crockett Times SI (Refs. 11, pp. 2, 15, 18; 42, pp. 6, 12). During this investigation, ground water samples collected from municipal well Nos. 1 and 2 (CT

- AWD1

- PW, CT

- AWD2

- PW, and CT

- AWD2D

PW) contained 1,1

- DCE; PCE; 1,1,1

- TCA; and/or TCE. The ground water sample collected from municipal well No. 4 ( CT

- AWD4

- PW) did not contain these hazardous substances (Ref. 11, p. 30). Therefore, ground water sample CT

- AWD4

- PW, collected from the City of Alamo’s municipal well No. 4, is used to represent background concentrations for ground water samples collected from the City of Alamo’s municipal well Nos. 1 and 2 (Ref. 11, pp. 20, 30) (see Section 2.2.1, Source No. 1, of this HRS documentation record). All City of Alamo municipal wells are screened in the Memphis Sand aquifer (Ref. 55). Based on its upgradient location and absence of contamination, temporary monitoring well CT

0 6

- GP is used to represent background for downgradient temporary monitoring wells (Ref. 11, pp. 15

, 31).

Background and observed release municipal well ground water samples were col lected during the same sampling event, from similar depth intervals, and in accordance with the same sampling procedures (Refs. 11, p. 14; 42; 53, Section 8). Background and observed release temporary monitoring well ground water samples were collected du ring the same sampling event, from similar depths, and in accordance with the same sampling procedures (Refs. 11, p. 14; 42; 53, Section 7). Temporary monitoring wells were installed and background ground water samples were collected in accordance with th e EPA Region 4 Environmental Investigations Standard Operating Procedures and Quality Assurance Manual (EISOPQAM) , November 2001 (Refs. 11, p. 14; 53, Sections 6, 7, and 8). The locations of the background ground water samples are depicted on Figure 7, pa ge 15 in Reference 11. Logbook notes are contained in Reference 42

, and chain

- of

- custody records are contained in References 66 and 78

.

TABLE 5 : Background Ground Water Samples

– January 2004

Sample ID Total Depth (feet amsl ) Date Sampled Location R eferences

CT

- AWD4

- PW 2 0 1 1/2 2 /2004 City of Alamo municipal well No. 4, s outh of West Park Street 7, Enclosure 3, p. E3

- 1; 11, pp. 15, 18 ; 39; 42, p. 6; 55; 78, p. 2

CT

- 0 6

- GP 288 1/21/2004 North west of the former Volunteer Circuits 11, p. 15; 39; 42, p. 4 ; 66,
p. 228 GW

- Likelihood of Release Notes:

amsl Above mean sea level AWD Alamo Water Department CT Crockett Times GP Geoprobe ID Identification number PW Potable well29 GW

- Likelihood of Release Background Concentrations

The background municipal well ground water sample was analyzed for VOCs by the E PA Region 4 Science and Ecosystem Support Division ( SESD ) Analytical Support Branch ( ASB ) in accordance with the ASB Laboratory Operations Quality Assurance Manual (LOQAM) (Ref s

. 20; 67 ; 78, p. 2 ). The minimum quantitation limits (MQL) are listed in the A SB LOQAM (Ref. 67, Chapter 7, Appendix 3). Each MQL corresponds to the lowest quantitative point on the calibration curve or the lowest demonstrated level of acceptable quantitation (Ref. 67, Chapter 5, p. 6). The MQLs are equivalent to sample quantitati on limits (SQL) (Ref. 21). The background temporary monitoring well ground water sample was analyzed for VOCs by a Contract Laboratory Program (CLP) laboratory in accordance with the EPA CLP SOW OLM04.3 for multi

- media, multi

- concentration organic analyti cal service (Refs. 11, Appendix B, p. B

- 6 5 ; 65; 66 , p. 2 ; 74). EPA Region 4 SESD reviewed all CLP data according to the
contract statement of work (SOW) and EPA guidelines (Ref. 20). Contract required quantitation limits ( CRQL) are provided in Reference 65. Analytical data sheets are contained in Appendix B of Reference 11. Form I data sheets from the CLP laboratory are contained in Reference 74.

TABLE 6 : Analytical Results for Background Samples

– January 2004

Sample ID Hazardous Substance Hazard ous Substance Concentration MQL/CRQL* References City of Alamo Municipal Well

CT

- AWD4

- PW 1,1

- DCE 1.0U μg/L 1 μg/L 11, Appendix B, p. B

- 4; 42, p. 6; 67, Chapter 7, Appendix 3, p. 2; 78, p. 2

CT

- AWD4

- PW PCE 1.0U μg/L 1 μg/L 11, Appendix B, p. B

- 4; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 2

CT

- AWD4

- PW 1,1,1

- TCA 1.0U μg/L 1 μg/L 11, Appendix B, p. B

- 4; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 2

CT

- AWD4

- PW TCE 1.0U μg/L 1 μg/L 11, Appendix B, p. B

- 4; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 2
Temporary Monitoring Well

CT

- 06

- GP PCE 10U μg/L 10 μg/L 11, Appendix B, p. B

- 65; 42, p. 4; 65,
p. 2 ; 66, p. 2; 74, p p

. ii, 14

Notes:

* The municipal ground water well samples are compared to MQLs contained in Reference 67, Chapter 7, Appe ndix 3. The temporary monitoring well ground water samples are compared to CRQLs contained in Reference 65. AWD Alamo Water Department CRQL Contract required quantitation limit CT Crockett Times DCA Dichloroethane DCE Dichloroethene GP Geoprobe ID Identif ication number μg/L Microgram s per liter MQL Minimum quantitation limit PW Potable well PCE Tetrachloroethene TCA Trichloroethane TCE Trichloroethene U The analyte was not detected at or above reporting limit.30 GW

- Likelihood of Release Contaminated Samples

The ground water sam ples listed in Table 7 were collected during the EPA January 2004 Crockett Times SI (Refs. 11, pp. 2, 15, 18; 42, pp. 5, 6, 13). Contaminated samples were collected from the City of Alamo’s municipal well Nos. 1 and 2

, as well as from temporary monitoring wells CT

- 03

- GP and CT

- 07

- GP (Refs. 11, p. 18; 42, pp. 5, 6, 1 3 ). The contaminated ground water samples listed in Table 7 were collected in accordance with the EPA Region 4 EISOPQAM, November 2001 (Refs. 11, p. 14; 53, Sections 7 and 8). Logbook notes ar e provided in Reference 42. The chain

- of

- custody records are provided in References 66 and 78 . The locations of the source samples listed in Table 7 are depicted on Figure 7, page 15 in Reference 11, and are described in Table 3, page 18 in Reference 11 (also see Figure 3 of this HRS documentation record).

TABLE 7 : Contaminated Ground Water Samples

– January 2004

Sample ID Total Depth (feet amsl ) Date Sampled Location References

CT

- AWD1

- PW 22 3 1/22/2004 City of Alamo municipal well No. 1, just nort h of West Park Street 7, Enclosure 3, p. E3

- 1 ; 11, p. 18; 39; 42, p. 6; 55; 78, p. 1

CT

- AWD2

- PW 224 .2 1/2 2 /2004 City of Alamo municipal well No. 2, just north of West Park Street 7, Enclosure 3, p. E3

- 1 ; 11, p. 18; 39; 42, p. 6 ; 55; 78, p. 1 CT

- AWD2D

- PW

CT

- 03

- GP 302 1/21/2004 South side of West Main Street, across from Crockett Times building 11, p. 15; 39; 42, p. 13; 66, p. 1

CT

- 07

- GP 292 1/21/2004 Just east of City of Alamo municipal well No. 1 11, p. 15; 39; 42, pp. 4, 5; 66, p. 2

Notes:

amsl Above mean sea level AWD Alamo Water Department CT Crockett Times D Duplicate GP Geoprobe ID Identification number PW Potable well31 GW

- Likelihood of Release Contaminated Concentrations

Municipal well ground water samples were analyzed for VOCs by the EPA Region 4 SESD ASB in

ac cordance with the ASB LOQAM (Ref s

. 20; 67 ; 78, p. 1 ). The MQLs are listed in the ASB LOQAM (Ref. 67, Chapter 7, Appendix 3). Each MQL corresponds to the lowest quantitative point on the calibration curve or the lowest demonstrated level of acceptable qua ntitation (Ref. 67, Chapter 5, p. 6). The MQLs are equivalent to SQLs (Ref. 21). Temporary monitoring well ground water samples were analyzed for VOCs by a CLP laboratory in accordance with the EPA CLP SOW OLM04.3 for multi

media, multi

- concentration org anic analytical service (Refs. 11, Appendix B, pp. B

- 62, B

- 66; 65; 66; 74). EPA Region 4 SESD reviewed all CLP data according to the contract SOW and EPA guidelines (Ref. 20). CRQLs are provided in Reference 65. Analytical data sheets are contained in A ppendix B of Reference 11. Form I data sheets from the CLP laboratory are contained in Reference 74.

TABLE 8 : Analytical Results for Contaminated Samples

– January 2004

Sample ID Hazardous Substance Hazardous Substance Concentration MQL/CRQL* Reference s

City of Alamo Municipal Wells

CT

- AWD1

- PW 1,1

- DCE 14A μg/L 1 μg/L 11, Appendix B, p. B

- 1; 42, p. 6; 67, Chapter 7, Appendix 3, p. 2; 78, p. 1

CT

- AWD1

- PW PCE 5.3A μg/L 1 μg/L 11, Appendix B, p. B

- 1; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD1

- PW 1,1,1

- TCA 3.4A μg/L 1 μg/L 11, Appendix B, p. B

- 1; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD1

- PW TCE 4.4A μg/L 1 μg/L 11, Appendix B, p. B

- 1; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2

- PW 1,1

- DCE 5.1A μ g/L 1 μg/L 11, Appendix B, p. B

- 3; 42, p. 6; 67, Chapter 7, Appendix 3, p. 2; 78, p. 1

CT

- AWD2

- PW PCE 13A μg/L 1 μg/L 11, Appendix B, p. B

- 3; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2

- PW 1,1,1

- TCA 1.2A μg/L 1 μg/L 11, Appendix B, p. B

- 3; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2

- PW TCE 1.0A μg/L 1 μg/L 11, Appendix B, p. B

- 3; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2D

- PW 1,1

- DCE 5.0A μg/L 1 μg/L 11, Appendix B, p. B

- 2; 42, p. 6; 67, Chapter 7, Appendix 3, p. 2; 78, p. 1

CT

- AWD2D

- PW PCE 13A μg/L 1 μg/L 11, Appendix B, p. B

- 2; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2D

- PW 1,1,1

- TCA 1.2A μg/L 1 μg/L 11, Appendix B, p. B

- 2; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1

CT

- AWD2D

- PW TCE 1.0A μg/L 1 μg/L 11, Appendix B, p. B

- 2; 42, p. 6; 67, Chapter 7, Appendix 3, p. 4; 78, p. 1
Temporary Monitoring Wells

CT

- 03

- GP PCE 48 μg/L 10 μg/L 11, Appendix B, p. B

- 62; 42, p. 13; 65, p. 2 ; 66, p. 1; 74, p p

. ii, 832 GW

- Likelihood of Release TABLE 8 : Analytical Results for Contaminated Samples

– January 2004

Sample ID Hazardous Substance Hazardous Substance Concentration MQL/CRQL* Reference s

CT

- 07

- GP PCE 240 μg/L 10 μg/L 11, Appendix B, p. B

- 66; 42, p. 5; 65, p. 2; 66, p. 2 ; 74, p p. ii, 20

Notes:

* The municipal ground water well samples are compared to MQLs contained in Reference 67, Chapter 7, Appendix 3. The temporary monitoring well ground water sa mples are compared to CRQLs contained in Reference 65. A Analyte analyzed in replicate; reported value is “average” of replicates. AWD Alamo Water Department CRQL Contract required quantitation limit CT Crockett Times D Duplicate DCA Dichloroethane DCE Dic hloroethene GP Geoprobe ID Identification number μg/L Microgram s per liter MQL Minimum quantitation limit PCE Tetrachloroethene PW Potable well TCA Trichloroethane TCE Trichloroethene33 GW

- Likelihood of Release EP A May 2010 ACGW Site Expanded Site Inspection

Background Samples

Th e background ground water samples listed in Table 9 were collected during the EPA May 2010 ACGW site ESI (Refs. 7, Enclosure 3, p. E3

- 1; 8, p. 12; 36, p p

. 9, 10). City of Alamo municipal well No. 4 (AG04) is located south and downgradient of the ACGW site and is used to represent background concentrations for ground water samples collected from the City of Alamo’s municipal well Nos. 1, 2, and 3 (Ref. 7, Enclosure 3, p. E3

- 1 ; 47, pp. 3, 4, 20 ) (see Figure 3 of this HRS documentation record). Ground water samples collected from background permanent monitoring wells AG06 and AG20 were collected northeast and east of the ACGW site. These locations are upgradient of ground water within and underlying the ACGW site (Ref. 7, Enclosure 3, p. E3

- 2) (see Figure 3 of this HRS documentation record). G round water samples collected from monitoring wells AG06 and AG20 are used to represent background concentrations for ground water samples collected from permanent monitoring wells located within the ACGW site (Ref. 7, Enclosure 1, pp. E1

- 1

, E1

- 2 , E1

- 27 , E1

- 28 ; 7, Enclosure 3, p. E3

- 2 ) (see Section 2.2.1, Source No. 1, of this HRS documentation record). B ackground City of Alamo municipal well No. 4 is screened from 119 to 159 feet bls (231 to 201 feet amsl) (Refs. 39; 5 5). Permanent monitoring well AG06 is screened from 70.43 to 90.43 feet bls (284.96 to 264.96 feet amsl)

, and AG20 is screened from 81.38 to 101.38 feet bls (286.71 to 266.71 feet amsl) (Ref. 7, Enclosure 2, Enclosure 6, pp. E6

- 1, E6

- 14). All ground wate r wells sampled during the EPA May 2010 ACGW site ESI are screened in the Memphis Sand aquifer (Refs. 7, Enclosure 1, Enclosure 4, p. E4

- 1; 55).

Background ground water samples and downgradient ground water samples within the plume were collected duri ng the same investigation, in accordance with similar sampling procedures, from wells that are screened in the same aquifer (Refs. 7, Enclosure 1, Enclosure 4, p. E4

- 1; Enclosure 5, p. E5

- 41; 19; 36; 38, p. 6; 40; 55). Background permanent monitoring well s were installed in accordance with the EPA Region 4 SESD Field Branches Quality System and Technical Procedures guidance document for Design and Installation of Monitoring Wells, SESDGUID

- 101

- R0 (Refs. 7, Enclosure 5, p. E5

- 41; 38, p. 6; 80). B ackground ground water samples were collected in accordance with the EPA Region 4 SESD Field Branches Quality System and Technical Procedures for Groundwater Sampling, SESDPROC

- 301

- R1 (Refs. 7, Enclosure 5, p. E5

- 41; 19; 3 8, p. 6). The locations of the background g round water samples collected from AG04, AG06

, and AG20 are depicted on page E3

- 1 of Enclosure 3 in Reference 7. Logbook notes are contained in Enclosure 5 of Reference 7 and in Reference 40. C hain

- of

- custody records are contained in Reference s 36.

TABLE 9 : Background Ground Water Samples

– May 2010

Sample ID Total Depth (feet amsl ) Date Sampled Location References City of Alamo Municipal Well

AG04

- 0510

- MS 201 5/13/2010 South of West Park Street 7, Enclosure 3, p. E3

- 1; 36, p. 9; 39; 40, p. 3; 5 5
Permanent Monitoring Wells

AG06

- 0510

- MW 265. 17 1 5/26/2010 North eastern portion of the City of Alamo 7, Enclosure 2; 7, Enclosure 3 , p. E 3

- 1; 7, Enclosure 5 , p. E 5

- 62 ; 7, Enclosure 6 , p. E 6

- 1 ; 3 6 , p. 10

A G 20

- 0510

- MW 26 6

. 71 1 5/26/2010 Eastern portion of the City of Alamo 7, Enclosure 2; 7, Enclosure 3 , p. E 3

- 1; 7, Enclosure 5 , p. E 5

- 62 ; 7, Enclosure 6 , p. E 6

- 14 ; 3 6 , p. 101 Notes:

Depth measured from top of casing AG Alamo Contaminated Ground Water amsl Above mean sea level ID Identification number MS Municipal well MW Monitoring well

Background Concentrations

Background samples were analyzed for VOCs in acco rdance with the EPA CLP SOW SOM01.2 (Refs. 9, pp. 1, 2; 37). EPA Region 4 SESD reviewed all data according to the contract SOW and EPA guidelines (Refs. 9, p. 2; 20). The minimum reporting limits (MRL) are listed on the analytical data sheets in Reference 9. Each MRL is sample-specific and corresponds to the lowest quantitative point on the calibration curve; it is adjusted for the amount of sample prepared and any dilutions performed. The MRLs are equivalent to SQLs (Ref. 21). Form I data sheets from the CLP laboratory are contained in Reference 79.

TABLE 10: Analytical Results for Background Samples – May 2010

Sample ID Hazardous Substance Hazardous Substance Concentration MRL References City of Alamo Municipal Well

AG04-0510-MS 1,1-DCE 0.50U μg/L 0.50 μg/L 9, p. 40; 36, p. 9; 40, p. 3; 79, pp. ii, 13

AG04-0510-MS PCE 0.34J (3.4) μg/L 0.50 μg/L 9, p. 41; 33, pp. i, 1; 34, pp. 8, 12; 36, p. 9; 40, p. 3; 79, pp. ii, 14

AG04-0510-MS TCE 0.50U μg/L 0.50 μg/L 9, p. 41; 36, p. 9; 40, p. 3; 79, pp. ii, 13
Permanent Monitoring Wells

AG06-0510-MW PCE 0.50U μg/L 0.50 μg/L 7, Enclosure 6, p. E6-1; 9, p. 43; 36, p. 10; 79, pp. ii, 17

AG20-0510-MW 1,2-DCA 0.50U μg/L 0.50 μg/L 7, Enclosure 6, p. E6-14; 9, p. 107; 36, p. 10; 79, pp. ii, 61

AG20-0510-MW PCE 0.50U μg/L 0.50 μg/L 7, Enclosure 6, p. E6-14; 9, p. 108; 36, p. 10; 79, pp. ii, 62

Notes:

( ) Concentration shown in parentheses was adjust ed in accordance with References 33 and 34. AG Alamo Contaminated Ground Water DCA Dichloroethane DCE Dichloroethene ID Identification number J The identification of the analyte is acceptable; the reported value is an estimate. μg/L Microgram per liter MRL Minimum reporting limit MS Municipal well MW Monitoring well PCE Tetrachloroethene TCA Trichloroethane TCE Trichloroethene U The analyte was not detected at or a bove the minimum or method reporting limit. UJ The analyte was not detected at or above the reporting limit; the reported value is an estimate.

34 GW-Likelihood of Release35 GW

- Likelihood of Release Contaminated Samples

The ground water samples listed in Table 1 1 were collected during the EPA May 2010 ACGW site ESI (Refs. 7, Enclosure 3, p. E3

- 1; 36, pp. 9, 10, 11). Ground water samples were colle cted from the City of Alamo’s municipal wells. City of Alamo municipal well screen intervals are as follows: No. 1 is 102 to 127 feet bls (248 to 223 feet amsl), No. 2 is 100.8 to 125.8 feet bls (249.2 to 224.2 feet amsl), and No. 3 is 168 to 213 feet bl s (182 to 137 feet amsl) (Refs. 39; 55). In addition, ground water samples were also collected from permanent monitoring wells installed in the City of Alamo (Refs. 7, Enclosure 5, pp. E5

- 62, E5

- 63; 40, pp. 2 through 5). Permanent monitoring well screen intervals are as follows: AG08 is 80.9 to 100.9 feet bls (278.93 to 258.93 feet amsl), AG09 is 80.24 to 100.24 feet bls (284.9 to 264.9 feet amsl), AG15 is 90.5 to 110.5 feet bls (263.77 to 243.77 feet amsl), AG17 is 65.83 to 85.83 feet bls (295.34 to 275 .34 feet amsl), and AG18 is 80.3 to 100.3 feet bls (281.02 to 261.02 feet amsl) (Ref. 7, Enclosure 2, Enclosure 6, pp. E6

- 3, E6

- 4, E6

- 9, E6

- 11, E6

- 12). Permanent monitoring wells were installed in accordance with the EPA Region 4 SESD Field Branches Quali ty System and Technical Procedures guidance document for Design and Installation of Monitoring Wells, SESDGUID

- 101

- R0 (Refs. 7, Enclosure 5, p. E5

- 41; 80). Contaminated ground water samples were collected in accordance with the EPA Region 4 SESD Field Bra nches Quality System and Technical Procedures for Groundwater Sampling, SESDPROC

- 301

- R1 (Refs. 7, Enclosure 5, p. E5

- 41; 19; 38, p. 6). Logbook notes are provided in Enclosure 5 of Reference 7 and in Reference 40. The chain

- of

- custody records are provide d in Reference 36. The locations of the source samples listed in Table 11 are depicted on page E3

- 1 of Enclosure 3 in Reference 7 (also see Figure 3 of this HRS documentation record).

TABLE 1 1 : Contaminated Ground Water Samples

– May 2010

Sample ID T otal Depth (feet amsl ) Date Sampled Location References City of Alamo Municipal Wells

AG01

- 0510

- MS 223 5/13/2010 City of Alamo municipal well No. 1, just north of West Park Street 7, Enclosure 3 , p. E 3

- 1 ; 3 6

, p. 9 ; 39; 40, p. 2 ; 55 AG01

- 0510

- MSD

A G02

- 0510

- MS 224.2 5/13/2010 City of Alamo municipal well No. 2 , just north of West Park Street 7, Enclosure 3, p. E3

- 1; 3 6

, p. 9 ; 39; 40, p. 5 ; 55

AG03

- 0510

- MS 137 5/13/2010 City of Alamo municipal well No. 3 , just north of West Park Street 7, Enclosure 3 , p. E3

- 1; 3 6

, p. 9 ; 39; 40, p. 4 ; 55

Permanent Monitoring Wells

AG08

- 0510

- MW 25 8

. 9 3 1 5/27/2010 On South Johnson Street, in town square 7, Enclosure 2; 7, Enclosure 3 , p. E 3

- 1 ; 7, Enclosure 5 , p. E 5

- 62; 7, Enclosure 6 , p. E 6

- 3; 3 6 , p. 10

AG09

- 0510

- MW 26 4.9 1 5/27/2010 On South Johnson Street, in town square 7, Enclosure 2; 7, Enclosure 3

, p. E3

- 1 ; 7, Enclosure 5 , p. E 5

- 62; 7, Enclosure 6 , p. E 6

- 4; 3 6 , p. 10

AG15

- 0510

- MW 243.7 7 1 5/28/2010 Just outside of Alamo Water Department b uilding 7, Enclosure 2; 7, Enclosure 3

, p. E3

- 1 ; 7, Enclosure 5 , p. E 5

- 63; 7, Enclosure 6 , p. E 6

- 9; 8, p. 19; 3 6 , p. 11

AG17

- 0510

- MW 275.34 1 5/28/2010 At intersection of South Burns Street and West Park Street 7, Enclosure 2; 7, Enclosure 3

, p. E3

- 1 ; 7, Enclosure 5 , p. E 5

- 63; 7, En closure 6 , p. E 6

- 11; 3 6 , p. 1136 GW

- Likelihood of Release TABLE 1 1 : Contaminated Ground Water Samples

– May 2010

Sample ID T otal Depth (feet amsl ) Date Sampled Location References

AG18

- 0510

- MW 261. 0 2 1 5/27/2010 Behind commercial building in town square 7, Enclosure 2; 7, Enclosure 3

, p. E3

- 1 ; 7, Enclosure 5 , p. E 5

- 62; 7, Enclosure 6 , p. E 6

- 12; 3 6 , p. 10 AG18

- 0510

- MWD

Notes:

1 Depth measured fr om top of casing AG Alamo Contaminated Ground Water amsl Above mean sea level D Duplicate ID Identification number MW Monitoring well MS Municipal well37 GW

- Likelihood of Release Contaminated Concentrations

Samples collected during the EPA May 2010 ACGW site ESI were analyzed for VOCs in accordance with the EPA CLP SOW SOM01.2 (Refs. 9, pp. 1, 2; 37). EPA Region 4 SESD reviewed all data according to the contract SOW and EPA guidelines (Refs. 9, p. 2; 20). The MRLs are listed on the analytical data sheets in Reference 9. Each MRL is sample

- specific and corresponds to the lowest quantitative point on the calibration curve; it is adjusted for the amount of sample prepared and any dilutions performed. The MRLs are equivalent to SQLs (Ref. 21). Form I data sheets from the CLP labora tory are contained in Reference 79.

TABLE 1 2 : Analytical Results for Contaminated Samples

– May 2010

Sample ID Hazardous Substance Hazardous Substance Concentration MRL References City of Alamo Municipal Wells

AG01

- 0510

- MS 1,1

- DCE 3.5 μg/L 0.50 μg/ L 9, p. 32; 36, p. 9; 40, p. 2; 7 9 , p. 1

AG01

- 0510

- MS PCE 16 μg/L 0.50 μg/L 9, p. 33; 36, p. 9; 40, p. 2; 7 9 , p. 2

AG01

- 0510

- MS TCE 1.7 μg/L 0.50 μg/L 9, p. 33; 36, p. 9; 40, p. 2; 7 9 , p. 1

AG01

- 0510

- MSD 1,1

- DCE 3.9 μg/L 0.50 μg/L 9, p. 34; 36, p . 9; 40, p. 2; 7 9 , p. 4

AG01

- 0510

- MSD PCE 16 μg/L 0.50 μg/L 9, p. 35; 36, p. 9; 40, p. 2; 7 9 , p. 5

AG01

- 0510

- MSD TCE 1.8 μg/L 0.50 μg/L 9, p. 35; 36, p. 9; 40, p. 2; 7 9 , p. 4

AG02

- 0510

- MS PCE 18 μg/L 0.50 μg/L 9, p. 37; 36, p. 9; 40, p. 5; 7 9 , p. 8

AG03

- 0510

- MS 1,1

- DCE 2.6J (2.6) μg/L 0.50 μg/L 9, p. 38; 33, p. 1; 34, p. 8; 35, p. 2; 36, p. 9; 40, p. 4; 7 9 , p. 10

AG03

- 0510

- MS TCE 1.1J (0.66) μg/L 0.50 μg/L 9, p. 39; 33, pp. i, 1; 34, pp. 8, 12; 36, p. 9; 40, p. 4; 7 9 , p. 10

Permanent Monitori ng Wells

AG08

- 0510

- MW PCE 0.67 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 62; 7, Enclosure 6, p. E6

- 3; 9, p. 51; 36, p. 10; 7 9 , p. 23

AG09

- 0510

- MW PCE 0.61 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 62; 7, Enclosure 6, p. E6

- 4; 9, p. 55; 36, p. 10; 7 9 , p. 26

AG15

- 0 510

- MW PCE 0.92 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 63; 7, Enclosure 6, p. E6

- 9; 9, p. 83; 36, p. 11; 7 9 , p. 44

AG17

- 0510

- MW 1,2

- DCA 4.0 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 63; 7, Enclosure 6, p. E6

- 11; 9, p. 91; 36, p. 11; 7 9 , p. 49

AG18

- 0510

- MW PCE 1 .2 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 62; 7, Enclosure 6, p. E6

- 12; 9, p. 96; 36, p. 10; 7 9 , p. 53

AG18

- 0510

- MWD PCE 1.1 μg/L 0.50 μg/L 7, Enclosure 5, p. E5

- 62; 7, Enclosure 6, p. E6

- 12; 9, p. 98; 36, p. 10; 7 9 , p. 5638 GW

- Likelihood of Release Notes:

( ) Concentrations shown in parentheses were adjusted in accordance with References 33, 34, and 35

. AG Alamo Contaminated Ground Water D Duplicate DCA Dichloroethane DCE Dichloroethene ID Identification number J The identification of the analyte is acceptable; the reported v alue is an estimate. μg/L Microgram s per liter MRL Minimum reporting limit MW Monitoring well MS Municipal well PCE Tetrachloroethene TCE Trichloroethene39 GW

- Likelihood of Release Attribution

Ground water samples collected from the City of Alamo’s municipal wells in 1988 and 1989 revealed VOC contamination in municipal well No. 1, including but not limited to 1,1

- DCE; 1,1,1

- TCA; and TCE (Refs. 48, pp. 1 through 4; 49, pp. 1 through 4; 50, pp. 1 through 24). VOCs were also detected in well Nos. 2 and 3 (Refs. 48, pp. 5 through 8; 50, pp. 25 through 38). In a sample collected by TDHE (currently TDEC) on September 2 0 , 1988, TCE was detected at a concentration of 97.9 μg/L in municipal well No. 1 (Ref. 48, p. 4). Another sample from September 1988 contained TCE at a concentration of about 113 μg/L (Refs. 10, p. 3; 52). Following the release of these sample results, use of the City’s municipal well No. 1 was immediately discontinued (Ref. 10, p. 3). As an interim remedial measure, the City resumed pumping well No. 1, although not fo r distribution, and discharged the water to a drainage ditch (Refs. 16; 30, p. 1). The City continued discharging water pumped from well No. 1 to a drainage ditch until July 2, 1991 when the City of Alamo installed an air stripper (Refs. 16; 29). At this time, municipal well No. 1 was put back into service and all City of Alamo municipal wells were monitored for VOC concentrations on a quarterly basis (Refs. 16; 29; 31, p. i; 32; 51, p. i). City of Alamo municipal well No. 1 is still in service at the ti me of this HRS documentation record (Ref. 29).

After the discovery of VOC contamination in the City of Alamo’s municipal wells, TDHE began investigating the possible sources of the contamination (Ref. 10, p. 1)

. Several possible sources of VOC
contam ination exist in the vicinity of the ACGW site. As discussed below, studies conducted to identify the source or sources of the contamination at the ACGW site did not generate compelling evidence linking the contamination observed in City of Alamo municipa l wells to any specific source, or combination of specific sources, other than the contaminated ground water plume itself. Moreover, any releases that may have occurred from possible sources are likely to have commingled over time, further complicating at tribution of contamination in the plume to any single source or combination of sources.

In 1989, USGS, in conjunction with TDHE Division of Superfund, conducted an investigation of the Memphis Sand aquifer at Alamo (Ref. 10, p. 1). The City of Alamo’s m unicipal wells are screened in the Memphis Sand aquifer (Ref. 55) . An underground gasoline storage tank, a vehicle maintenance building, and a former industrial site were identified near the wellfield (Ref. 10, pp. 10, 11). The industrial site was the fo rmer location of Volunteer Circuits, a printed circuit board manufacturing facility where organic solvents had been used in the cleaning of electronic components and in the film developer (Refs. 10, p. 3; 28, p. 5; 32; 69). TCE was detected in 13 of the 4 2 soil

- gas samples collected during this investigation

, with the highest concentrations detected at or near the former location of Volunteer Circuits, at a maximum concentration of 30 μg/kg (Ref. 10, pp. 10, 11). Ground water samples collected from munici pal well No. 1 contained the highest concentrations of TCE (45 μg/L); 1,1,

- DCE (32 μg/L); PCE (1.2 μg/L); and 1,1,1

- TCA (38 μg/L). Well No. 2 also contained TCE (0.7 μg/L); 1,1

- DCE (0.9 μg/L); and 1,1,1

- TCA (1.3 μg/L). VOCs were not detected in the other two municipal wells at the time of the investigation (Ref. 10, p. 8).

One possible source of the 1,1,1

- TCA, TCE, and 1,1

- DCE ( PCE/ TCE’s breakdown product) contamination in the ground water underlying the City of Alamo is Volunteer Circuits (Refs. 59, p. 24 ; 69 ). While initially considered the source (or at least a primary source) of the ground water contamination, subsequent investigations show that t he highest VOC concentrations were detected in boring locations northwest and side gradient of Volunteer Circuits, including 1,1

- DCE at 159 ppb; 1,1,1

- TCA at 125 ppb; and TCE at 31 ppb (Ref. 14, pp. 5, 6). One ground water sample collected northwest of Volunteer Circuits contained 1,1

- DCE (87 ppb); 1,1,1

- TCA (25 ppb); and TCE (6 ppb) (Refs. 6, pp. 20, 21, 23 ; 15, pp. 5, 6). PCE was detected in ground water samples collected east and upgradient of Volunteer Circuits, and southwest and downgradient of Volunteer Circuits (Ref s . 14, pp. 5, 6 ; 15, pp. 5, 6; 72, pp. 1, 2, 4). Volunteer Circuits manufactured print ed circuit boards for the electronic s industry from 1973 to 1975 (Ref. 71 ). According to the owner of Volunteer Circuits, spent TCE from the film developer was poured onto the ground when the developer was serviced (Ref. 69). Printed circuit board manufa cturing involves use of various cleaners including 1,1,1

- TCA and TCE (Ref. 28, p. 5).40 GW

- Likelihood of Release Another possible source of VOC (excluding PCE) contamination in ground water underlying the City of Alamo is The Crockett Times . Direct attribution of VOCs, while pre sent in ground water at the facility, has not been linked to facility operations. PCE contamination at the ACGW site may be attribut able to local dry cleaning businesses including the North Johnson Street dry cleaners and Ward’s Dry Cleaners (Refs. 44; 58 ) (also see the Summary of Source Descriptions in this HRS documentation record) . PCE is a common solvent used in the dry cleaning industry (Ref. 57, p. 1)

.

Other facilities possibly linked to VOC/solvent use within a 4

- mile radius of the approximate c enter of the ACGW plume include the East Church Street Site , Alamo Mills , and Tucker Automotive (Ref. 76)

. In August 2004, TDEC Division of Superfund conducted a prescreening investigation at the East Church Street Site located at 130 East Church Street, Alamo, Tennessee (Ref. 45, pp. 1, 2, 6, 24). A dry cleaner and laundry business operated on this property from 1968 to sometime in the late 1970s or early 1980s (Ref. 45, p. 2). Two samples were collected from the property, one soil sample and one sedime nt sample

, and were analyzed for VOCs (Ref. 45, pp. 5, 26, 35, 38) . The soil sample was collected from behind the building

, and the sediment sample was collected from a drainage ditch north of the building (Ref. 45, pp. 5, 26)

. VOCs were not detected in either sample (Ref. 45, pp. 36, 37, 39, 40). No ground water samples have been collected in the vicinity of the East Church Street dry cleaner (Ref. 45, p. 3).

In December 2007, TDEC Division of Remediation, on behalf of EPA, prepared a pre

- CERCLIS

scree ning assessment report for the Alamo Mills facility located at 472 South Mill Street, Alamo, Tennessee (Ref. 46, pp. i, 2). Alamo Mills operated as a clothing manufacturing plant from the 1960s until 2003. Garments manufactured at the plant were knitted, sewn, dyed, cleaned, and packaged. An unknown dry cleaning solvent was used to clean garments prior to packaging (Ref. 46, pp. 2, 4). Drums of dry cleaning fluid were stored in an alley between two building sections. Degreasers were also used at the pl ant (Ref. 46, p. 4). Two possible source areas were identified at the Alamo Mills property: (1) the wastewater treatment lagoon that has since been closed and backfilled, and (2) the drum storage area

, where s tressed vegetation was observed (Ref. 46, p. 4). The Alamo Mills property is located south and side gradient of the ACGW plume and the City of Alamo municipal wellfield (Ref s . 7, Enclosure 3, p. E3

- 2; 46, p. 11) (also see Figure 2 of this HRS documentation record)

. No soil or ground water samples we re collected during this assessment.

Tucker Automotive is a possible source of VOC contamination in the City of Alamo area. Since 1946, the Tucker Automotive property, located at 146 South Bells Street, has been used as a gas station, auto repair shop, a uto body shop, machine shop, and for storage (Ref. 43, p. 2). In June 2000, during TDEC’s investigation of Volunteer Circuits, ATC collected a ground water sample from a temporary monitoring well installed on the Tucker Automotive property (Ref. 14, pp. 3 , 6). TCE and PCE were not detected in the ground water at this location; however, benzene was detected at a concentration of 51 ppb (Ref. 14, p. 6, Appendix A, p. A

- 4 ). Benzene was also detected in Alamo’s municipal well No. 4 during the January 2004 Cr ockett Times SI and the May 2010 ACGW site ESI at concentrations of 10A μg/L and 0.69 μg/L, respectively (Refs. 9, p. 40; 11, Appendix B, p. B

- 4). Alamo’s municipal well No. 4 is downgradient of Tucker Automotive (Ref. 7, Enclosure 3, p. E3

- 2) (see Figure 2 of this HRS documentation record) . In July 2000, TDEC Division of Superfund conducted a prescreening investigation at this property. Evidence of underground storage tanks was present at the time of the investigation (Ref. 43, p. 3).

Additionally, f ou r RCRA facilities have been identified in Alamo, Tennessee, including Angelica Uniform Group, Brown Chevrolet Inc. , Partners Pallets, and Skelton Trucking. The Angelica Uniform Group facility is located at 101 West Park Street. Angelica Corporation, whic h owns Angelica Uniform Group, provides textiles and apparel for the service industry (Refs. 60, pp. 1, 2; 61). Specific operations and waste management practices employed at Angelica Uniform Group are not known

. T his facility is located downgradient of the ACGW plume (Refs. 7, Enclosure 3, p. E3

- 2; 60, p. 1). No ground water samples have been collected in the vicinity of the Angelica Uniform Group

.
Brown Chevrolet Inc. is located north and sidegradient of the ACGW site at 172 North Bells Street (Refs. 7, Enclosure 3, p. E3

- 2; 62, p. 1). It is listed in RCRA as an automotive mechanical and electrical repair and maintenance facility (Ref. 62, p. 1). Specific operations and waste management practices employed41 GW

- Likelihood of Release at the Brown Chevrolet facility are not known

. No ground water samples have been collected in the vicinity of Brown Chevrolet Inc.

Partners Pallets is located at 220 South Burns Street. It is listed in RCRA as an ice manufacturer (Ref. 63, p. 1). Specific operations and waste management practices employed at Partners Pallets are not known

. T his facility is located downgradient of the ACGW plume ; it is not expected to be a source for the VOC contamination detected in the City of Alamo’s municipal wells or monitoring wells located within the ACGW s ite (Refs. 7, Enclosure 3, p. E3

- 2; 63, p. 1). No ground water samples have been collected in the vicinity of Partners Pallets.

Skelton Trucking is located at 226 East Elm Street, near the location of background permanent monitoring well AG06 installed i n May 2010 (Ref s

. 7, Enclosure 3, p. E3

- 1; 64, p. 1). It is listed in RCRA as a general freight trucking facility (Ref. 64, p. 3). Specific operations and waste management practices employed at the Skelton Trucking facility are not known. No ground wate r samples have been collected in the vicinity of Skelton Trucking.

The hazardous substances listed below have been documented in ground water samples collected from the City of Alamo ’s municipal wells and permanent monitoring wells located within the ACGW contaminated ground water plume (see Tables 2 and 4 in Section 2.2.2 for Source No. 1, and Tables 11 and 1 5 in Section 3.1.1, Observed Release, of this HRS documentation record). Several possible sources of VOC contamination exist in the vicinity of the ACGW site; however, the contamination cannot be directly attributed to any specific source, or combination of specific sources. PCE is a common solvent used in the dry cleaning industry (Refs. 57, p. 1 ).

Hazardous Substances in the Release

1,1

- DCE 1,2

- D CA PCE 1,1,1

- TCA TCE

Ground Water Observed Release Factor Value: 550.0042 GW

- Likelihood o f Release 3.1.2 POTENTIAL TO RELEASE

Potential to release was not evaluated for the Memphis Sand aquifer because an observed release has been documented (see Section 3.1.1 of this HRS docume ntation record).43 GW

- Waste Characteristics 3.2 WASTE CHARACTERISTICS

3.2.1 TOXICITY/MOBILITY

The toxicity and mobility factor values for the hazardous substances detected in the source samples with containment factor values of greater than 0 are summarized in Table 1 3 . The c ombined toxicity and mobility factor values are assigned in accordance with Reference 1, Section 3.2.1. Hazardous substances detected in the observed release to ground water are assigned a mobility factor value of 1 (Ref. 1, Section 3.2.1.2).

TABLE 1 3 : Ground Water Toxicity/Mobility

Hazardous Substance Source No. Toxicity Factor Value Mobility Factor Value Does Hazardous Substance Meet Observed Release? (Yes/No) Toxicity/ Mobility ( Ref. 1, Table 3

- 9) R eference
1,1

- DCE 1 100 1 Yes 100 2, p. BI

- 5
1,2

- DC A 1 100 1 Yes 100 2, p. BI

- 4

PCE 1 100 1 Yes 100 2, p. BI

- 10
1,1,1

- TCA 1 1 1 Yes 1 2, p. BI

- 11

TCE 1 10,000 1 Yes 10,000 2, p. BI,B2

- 1

Notes:

DCA Dichloroethane DCE Dichloroethene No. Number PCE Tetrachloroethene TCA Trichloroethane TCE Trichloro ethene

Toxicity/Mobility Factor Value: 10,000.00 (Ref

. 1, Table 3

- 9)44 GW

- Waste Characteristics 3.2.2 HAZARDOUS WASTE QUANTITY

TABLE 1 4 : Hazardous Waste Quantity

Source No. Source Type Source Hazardous Waste Quantity

1 Other

– Ground water plume with

no identified source Un determined, but greater than zero

The hazardous constituent quantity for Source No. 1 is not adequately determined. The HWQ is undetermined, but greater than zero. Because Level I contamination is present in a drinking water well, the HWQ receives a mi nimum factor value of 100 for the ground water migration pathway (Ref. 1, Section 2.4.2.2 )

.
Hazardous Waste Quantity Factor Value: 10 0 (Ref

. 1, Sec tion 2.4.2.2)

3.2.3 WASTE CHARACTERISTICS FACTOR CATEGORY VALUE

The waste characteristics factor category was obtained by multiplying the toxicity/mobility and HWQ factor values, subject to a maximum product of 1 × 10 8 . Based on this product, a value was assigned in accordance with Reference 1, Table 2

- 7.

Toxicity/Mobility Factor Value: 10,000.00 Hazardous W aste Quantity Factor Value: 10 0

Toxicity/Mobility Factor Value × Hazardous Waste Quantity Factor Value: 1 ,0 00,000.00 (1 × 10 6 )

Waste Characteristics Factor Category Value: 32 (Ref

. 1, Table 2

- 7)45 GW

- Targets 3.3 TARGETS

Residents of the City of Alamo are p rovided drinking water from the Alamo Water Department municipal system (Ref. 5 5 ). The Alamo Water Departme nt operates four wells, municipal well Nos. 1 through 4. Well Nos. 1, 2, and 3 are located just north of West Park Street

, and w ell No. 4 is locate d south of West Park Street (Ref. 7, Enclosure 3, p. E3

- 1) (see Figure 3 of this HRS documentation record)

. The total depths of the City of Alamo municipal wells are as follows: w ell No. 1 is 127 feet bls (22 3 feet amsl), w ell No. 2 is 125.8 feet bls (22 4 .2 feet amsl), w ell No. 3 is 213 feet bls (13 7 feet amsl), and well No. 4 is 1 59 feet bls (2 0 1 feet amsl) (Ref s

. 39; 55 ). All Alamo Water Department municipal wells have wellhead protection areas and withdraw from the Memphis Sand aquifer (Ref s

. 1 8 ; 47 , p p

. 3, 4 ; 55 ; 68; 77 ). Water is blended before distribution to 3,056.24 residents (1,208 connections in May 2010 x 2.53 persons per household) and no one well contributes more than 40 percent of the municipal water supply , resulting in an average populatio n served per well of 7 64

. 06 (3,056.24 residents ÷ 4 wells) (Ref s

. 5 5 ; 75 ).

The C ounty

- W ide Utility District (CWUD) operates 15 wells connected to seven water plants , which serve

seven routes in five counties (Ref. 56)

. Two routes, Route 5a (Egg Hill Wa ter Plant ) and Route 5b (HWY 412 Water Plant ), are located within 4 miles of the approximate center of the ACGW plume (Refs. 3; 56)

. Each of these water plants maintains two wells (Ref. 56). The CWUD wells and their associated potential contamination pop ulation targets are not scored in this HRS documentation record.

The City of Alamo’s municipal wells

, located within a 4

- mile radius of the approximate center of the ACGW plume

, provide drinking water to about 3,056.24 people. The population served by these wells per distance ring is distributed as follows: > 0 to 0.25 mile, 3,056.24 people; > 0.25 to 0.50 mile, 0 people; > 0.50 to 1 mile, 0 people; > 1 to 2 miles, 0 people; > 2 to 3 miles, 0 people; > 3 to 4 miles, 0 people (Refs. 3; 55 ; 75 ) (also s ee Table 1 5 of this HRS documentation record). All of the wells within the 4

- mile radius are screened in the Memphis Sand aquifer (Ref s

. 55; 56 ). The City of Alamo maintains wellhead protection

areas

. Therefore, wellhead protection areas are located wit hin S ource No. 1 at the ACGW site (Ref s

. 18 ; 47 ; 56; 68 ; 77 ). Three City of Alamo municipal wells (Nos. 1, 2, and 3) are located within the plume and are scored as actual contamination targets at Level I concentrations (see Section 3.3.3.2). City of Alam o municipal well No. 4 is located within 0.25 mile of the approximate center of the ACGW plume . Its drinking water population would be scored as potential contamination targets; however, potential contamination was not scored.

TABLE 1 5 : Municipal and Co unty Drinking Water Wells Within a 4

- Mile Radius of the Approximate Center of the ACGW Plume Memphis Sand Aquifer

Distance

Ring Miles Water System Name No. of Wells Well No. and Depth of Wells (feet bls) Level I Cont. (Y/N) Level II Cont. (Y/N) Pot

. Con t. (Y/N) Pop

. Served References

> 0 to 0.25 City of Alamo 3 Well No. 1

– 127 Well No. 2

– 125.8 Well No. 3

– 213 Y N N 2,2 92

. 18 55 ; 75

> 0 to 0.25 City of Alamo 1 Well No. 4

– 1 59 N N Y 764.06 55 ; 75

Notes:

> Greater than bls Below land surface Cont. C ontamination CWUD County

- Wide Utility District ID Identification number N No No. Number Pop. Population Pot. Potential Y Yes46 GW

- Targets Level I Samples

Ground water samples listed in Table 1 6 were collected from the City of Alamo’s municipal drinking water wells ins talled in the Memphis Sand aquifer located within the ACGW site in May 2010 (Refs. 7, Enclosure 3, p. E3

- 1; 36, p. 9; 40; 55) (see Figure 3 of this HRS documentation record) . The samples were analyzed by a CLP laboratory for VOCs (Ref. 9, pp. 1, 2) . The analytical results and MRLs are provided in Reference 9.

TABLE 16: Level I Concentrations City of Alamo Municipal

Well ID Sample ID Hazardous Substance Hazardous Substance Concentration Benchmark Concentration Benchmark References

No. 1 AG01

- 0510

- MS PCE 16 μg/L 5 μg/L MCL 2, p. BII

- 11; 9, p. 33

No. 1 AG01

- 0510

- MS TCE 1.7 μg/L 0.21 μg/L CR 2, p. BI,B2

- 1; 9, p. 33

No. 1 AG01

- 0510

- MSD PCE 16 μg/L 5 μg/L MCL 2, p. BII

- 11; 9, p. 35

No. 1 AG01

- 0510

- MSD TCE 1.8 μg/L 0.21 μg/L CR 2, p. BI,B2

- 1; 9, p. 35

No. 2 AG02

- 0510

- MS PCE 18 μg/L 5 μg/L MCL 2, p. BII

- 11; 9, p. 3 7

No. 3 AG03

- 0510

- MS TCE 1.1J (0.66) μg/L 0.21 μg/L CR 2, p. BI,B2

- 1; 9, p. 39; 33, pp. i, 1; 34, pp. 8, 12

Notes:

( ) Concentration shown in parentheses w as adjusted in accordance with Refere nces 33, 34, and 35. AG Alamo Contaminated Ground Water CR Cancer risk screening concentration from SCDM (Ref. 2) D Duplicate ID Identification MCL Maximum contaminant level from SCDM (Ref. 2) μg/L Microgram s per liter MS Municipal well sample No. Number P CE Tetrachloroethene SCDM Superfund chemical data matrix TCE Trichloroethene47 GW

- Targets 3.3.1 NEAREST WELL

Because actual contamination at Level I concentrations has been documented, a nearest well factor value of 50 is assigned (Ref. 1, Section 3.3.1, Table 3

- 11).

Well ID: City of Alamo municipal well Nos. 1, 2, and 3 are located within the ACGW site (Refs. 7, Enclosure 3, p. E3

- 1 ) (see Figure 3 of this HRS documentation record)

. See Table 1 6 of this HRS documentation record for all drinking water wells evaluate d at Level I concentrations.

Level of Contamination (I, II, or potential): I

Nearest Well Factor Value: 5 0.0 ( Ref. 1, Section 3.3.1, Table 3

- 11 )

3.3.2 POPULATION

3.3.2.1 Level of Contamination

3.3.2.2 Level I Concentrations

A total of 2, 292.18 people are subject to actual contamination at Level I concentrations (Ref s

. 55 ; 75 ) (see Section 3.1.1

, Observed Release of this HRS documentation record) . Level I concent rations are documented in Table 16

. Municipal drinking water wells that contain PC E and TCE at concentrations above the MCL and/or the cancer risk screening concentration were evaluated as Level I targets and are presented in Table 17 . The population data for the drinking water wells listed in Table 17 were obtained from the Alamo Wate r Department and the U.S. Census Bureau (Ref s

. 55 ; 75 ).

TABLE 17: Level I Population City of Alamo

Municipal

Well ID Sample ID Hazardous Substance Population References

No. 1 AG01

- 0510

- MS AG01

- 0510

- MSD PCE TCE 764.06 9, pp. 33, 35; 55; 75

No. 2 AG0 2

- 0510

- MS PCE 764.06 9, p. 37; 55; 75

No. 3 AG03

- 0510

- MS TCE 764.06 9, p. 39; 55; 75

Notes:

AG Alamo Contaminated Ground Water D Duplicate ID Identification MS Municipal well sample PCE Tetrachloroethene TCE Trichloroethene

Sum of Population Served by Level I Wells: 2,292.18 Individuals Sum of Population Served by Level I Wells × 10: 22,921.8 Individuals

Level I Concentrations Factor Value: 22,921.848 GW

- Targets 3.3.2.3 Level II Concentrations

No Level II concentrations have been identified.

Level II Concentr ations Factor Value: 0.00 3.3.2.4 Potential Contamination

Potential contamination targets are not scored

Potential Contamination Factor Value: NS

3.3.2.5 CALCULATION OF POPULATION FACTOR VALUE

A value of 22,921.8 (Level I) is assigned for the populat ion factor value (Ref. 1, Section 3.3.2.5)

.
Total Population Factor Value: 22,921.8

3.3.3 RESOURCES

Wells used for resources were not identified within a 4

- mile radius of the ACGW site (Ref s

. 54; 55)

.

Resources Factor Value: 0.00

3.3.4 WELLHEAD PROTE CTION AREA

Tennessee’s Wellhead Protection Program was approved in July 1994 in accordance with Section 1453 of the 1996 Safe Drinking Water Act Amendments (Ref. 77, p. 1)

. The City of Alamo’s Wellhead Protection Plan was approved by TDEC Division of Wat er Supply on August 21, 1997 (Ref. 18). The City of Alamo maintains wellhead protection areas (Refs. 18; 47, pp. 3, 4; 68). Three of the City of Alamo’s municipal wells are located within the ACGW site (Refs. 3; 7, Enclosure 3 , p. E 3

- 1 ) (see Figure 3 of the HRS documentation record)

.

Wellhead Protection Area Factor Value: 20 .00