HRS DOCUMENTATION RECORD REVIEW COVER SHEET

Na me of Site: Hemphill Road TCE

NC0 002 374 44 5

Contact Persons: U.S. Environmental Protection Agency, Region 4: Jennifer Wendell, NPL Coordinator (404) 562-8799

Nor th Carolina Department of Environment and Natural Resources:

Site Investigation: Melanie Bartlett (919) 707 -8373

Documentation Record:

Melanie Bartlett (919) 707-8373

Pathways, Components, or Threats Not Evaluated:

The surface water migration, soil exposure, and air migration pathways were not scored in this Hazard Ranking System (HRS) documentation record because the ground water migration pathway is sufficient to qualify the site for National Priorities List (NPL). These pathways are of concern to the U.S. Environmental Protection Agency (EPA) and may be considered during a future evaluation.1 HRS DOCUMENTATION RECORD

Name of Site: Hemphill Road TCE

EPA Region: 4

Date Pre pared: May 2013

Stre et Address of Site*: Hemphill Road

Cit y, County, State, and ZIP: Gastonia, Gaston County, NC, 28056

Gene ral Location in the State: South Central North Carolina

Topogr aphic Map: Gastonia, NC

Latitude: 35.197933° N Longitude: -81.189852°W

The site reference point for the Hemphill Road TCE site is the approximate center of Hemphill Road where it crosses the unnamed tributary, which is with in the plume defined in Figure 3 (Ref. 3 ; Figs. 1, 3, 4).

* The street address, coordinates, and contaminant locations presented in this HRS documentation record identify the general area the site is located. They represent one or more locations EPA considers to be part of the site based on the screening information EPA used to evaluate the site for NPL listing. EPA lists national priorities among the known “releases or threatened releases” of hazardous substances; thus, the focus is on the release, not precisely delineated boundaries. A site is defined as where a hazardous substance has been “deposited, stored, disposed, or placed, or has otherwise come to be located.” Generally, HRS scoring and the subsequent listing of a release merely represent the initial determination that a certain area may need to be addressed under CERCLA. Accordingly, EPA contemplates that the preliminary description of facility boundaries at the time of scoring will be refined as more information is developed as to where the contamination has come to be located.

Scores Ground Water Pathway 100.00 Surface Water Pathway Not Scored Soil Exposure Pathway Not Scored Air Pathway Not Scored
HRS SITE SCORE 

### 50 .002 WORKSHEET FOR SITE SCORE

S S 2

1. Ground Water Migration Pathway Score 100.00 10,000

2a. Surface Water Overland/Flood Migration

--
Drinking Water Threat Not Scored

Food Chain Threat Not Scored

Environmental Threat Not Scored

Surface Water Overland/Flood Migration Component (subject to maximum value of 100, Ref. 1, section 4.1.5)

3. Soil Exposure Pathway Score Not Scored

4. Air Migration Pathway Score Not Scored

5. Total of S gw 2 + S sw 2 + S s 2 + S a 2 = 10,000

6. HRS Site Score: Value on line 5. divided by four, then take the square root 

### 50.003 T ABLE 3

- 1

-- G ROUND W ATER M IGRATION P ATHWAY S CORESHEET Factor categories and factors Maximum Value Value Assigned Aquifer Evaluated: Saprolite/bedrock Likelihood of Release to an Aquifer: 1. Observed Release 550 550 2. Potential to Release: 2a. Containment 10 0 2b. Net Precipitation 10 0 2c. Depth to Aquifer 5 1
2d. Travel Time 35 1 2e. Potential to Release [lines 2a(2b + 2c + 2d)] 500 0 3. Likelihood of Release (higher of lines 1 and 2e) 550 550 Waste Characteristics: 4. Toxicity/Mobility (a) 1000 5. Hazardous Waste Quantity (a) 100
6. Waste Characteristics 100 18 Targets:
7. Nearest Well (b) 50 8. Population: 8a. Level I Concentrations (b) 1 4 81 .3 8b. Level II Concentrations (b) 5 8c. Potential Contamination (b) 0 8d. Population (lines 8a + 8b + 8c) (b) 1 486 .3
9. Resources 5 0
10. Wellhead Protection Area 20 0 11. Targets (lines 7 + 8d + 9 + 10) (b) 1536.3 Ground Water Migration Score for an Aquifer:

c 12. Aquifer Score [(lines 3 x 6 x 11)/82,5000] 100 100.0 0

Ground Water Migration Pathway Score:

c 13. Pathway Score (S gw ), (highest value from line 12 for all aquifers evaluated) 100 10 0.0 0

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

c Do not round to nearest integerD########################### #######7###########################7#7###########################################**Source: Road Centerlines, Gaston County; County Boundary, NC DOT; Site Boundary, NC Div of Waste Management; Water Sources and Wells, NC Div Public Water Supply HEMPHILL ROAD TCE SITE** **4-MILE RADIUS WITH COMMUNITY WELLS** **1: 4-Mile Area NCD 002 374 445** **Gastonia, NC Gaston** **SMM Fig:** **Site: City** **County: Date:** **Drawn By: 1 inch = 4,000 feet** **0.9 0** **0.9 0.45** **Miles World Geographic System 1984** 2**09/20/2012 Public Water Supply Water Source** #**Community**#7**Non-Transient Non-Community**#0**Adjacent**D**Site Building Footprints** **Roads Streams & Rivers** **Water Bodies**..•.....

## r?:~~'Y:.················"·_ ..... 

# 8 · 

# N

........................ 

# -· GT-003-GW 

# s

R705\0**o~~~~r!i-SGT-004-GW** 

# • 

# II ·**\~I>~** Rl'OSS
Site Map 

# • R70511

# ~ GT O

## /S~~;OOS-GW North Carolina R705\2 - 12-GW

, . Department o l Environment, Health, and Natural Resources

. •lvls l on of Environmental Management Groundwater Section Pollution ln cldenl #3858 GT-011-GW GT-006-GW 

### S Gaston County

- Gibson Residence GT-009-GW 

# s GT-206-GW R 7 05 7 June 1994 A70515 

## 0

R705t•

GT-008-GWO

R705t3
SGT-010-GW Legend R705tS Graphic Seale 1• = 125' 

### S

· OEM Monitor Well

# ~

.. .**M11t** 

### v Well destroyed 

### 0 Well no long er visible

•• Building O Well dry during March 2012 ESI Sampling

. Event-No Sample Collected

Note: Basr: Map derived from tnlorgrd U.S.G.S. 7 1 11 min quadrangle map ofGastonlo Sowlt. WtllloC4lioJU havr: beer: verifisd (PSB). Nole: Building locatioltS and dimtnsloltS are only approxiniQtt. TBM elevation asswned as 760/1 abovt MSL at monitor wr:ll casing extension on well R7059

.

Figure 2: Monitoring Wells and GIT Production WellD

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Crowder Creek **Inset A**

**Inset B**

**Source: Gaston County, Parcels; Well Sample Locations, NC Division of Waste Management** 

### HEMPHILL ROAD TCE SITE
**HALF-MILE GROUNDWATER USE**

**3. Sample Locations**

**NC0 002 374 445**

**Gastonia, NC**

**Gaston**

**SMM Fig:** 

**Site:**

**City**

**County:**

**Date:**

**Drawn By:**

**1 inch = 800 feet**

**0.2 0**  **0.2 0.1**  **Miles North American Datum 1983**  **North Carolina State Plane (3200)**

**Contour Interval 4 Feet** 

# 2 **02/27/2013 1/2 Mile** 

! ( Detection - Level I (TCE)

! ( Detection - Level II (w/TCE)

! ( No Detection of TCE

Site/Extent of Plume

<-- BkgdD

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GT-206-GW GT-005-GW GT-012-GW GT-003-GW

GT-002-GW
GT-001-GW GT-013-PW Bkgd GT-085-PW GT-084-PW

GT-083-PW

GT-082-PW GT-081-PW GT-080-PW GT-079-PW GT-077-PW GT-076-PW GT-075-PW GT-074-PW GT-073-PW GT-072-PW GT-071-PW

GT-309-PW GT-304-PW GT-068-PW/ GT-268-PW GT-267-PW

GT-067-PW GT-066-PW GT-065-PW GT-064-PW

GT-052-PW

GT-051-PW GT-050-PW

GT-049-PW GT-048-PW GT-047-PW

GT-046-PW GT-045-PW

GT-044-PW GT-043-PW

GT-042-PW Bkgd GT-307-PW

GT-010-GW Bkgd GT-003-PW Bkgd (1999)

Kensington Estates closed 1999 Kensington Estates closed 1999

**Source: Gaston County, Parcels; Well Sample Locations, NC Division of Waste Management** 

### (A) HEMPHILL ROAD TCE SITE
**HALF-MILE GROUNDWATER USE**

**3-A. Sample Locations**

**NC0 002 374 445**

**Gastonia, NC**

**Gaston**

**SMM Fig:** 

**Site:**

**City**

**County:**

**Date:**

**Drawn By:**

**1 inch = 450 feet**

**0.1 0**  **0.1 0.05**  **Miles North American Datum 1983**  **North Carolina State Plane (3200)**

**Contour Interval 4 Feet** 

# 2 **02/27/2013 1/2 Mile** 

! ? Detection - Level I (TCE)

! ? Detection - Level II (w/TCE)

! ? No Detection of TCE! ?

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GT-019-PW GT-018-PW

GT-017-PW GT-016-PW/ GT-216-PW

GT-105-PW GT-104-PW GT-103-PW <-- RP-018-GW Bkgd RP-002-GW

RP-001-GW

GT-102-PW GT-101-PW GT-100-PW GT-099-PW

GT-098-PW GT-097-PW GT-096-PW

GT-095-PW GT-094-PW

GT-093-PW GT-092-PW

GT-091-PW

GT-090-PW GT-089-PW GT-087-PW/ GT-088-PW GT-086-PW GT-063-PW GT-062-PW GT-061-PW GT-060-PW

GT-059-PW GT-259-PW GT-106-PW

GT-058-PW GT-057-PW GT-056-PW GT-055-PW GT-054-PW GT-053-PW GT-041-PW

GT-040-PW GT-039-PW GT-038-PW

GT-037-PW

GT-036-PW GT-035-PW

GT-034-PW GT-301-PW Bkgd

GT-032-PW GT-031-PW

**Source: Gaston County, Parcels; Well Sample Locations, NC Division of Waste Management; Contour, NC DOT (Derived from 2007 LIDAR)** 

### (B) HEMPHILL ROAD TCE SITE
**HALF-MILE GROUNDWATER USE**

**3-B. Sample Locations**

**NC0 002 374 445**

**Gastonia, NC**

**Gaston**

**SMM Fig:** 

**Site:**

**City**

**County:**

**Date:**

**Drawn By:**

**1 inch = 450 feet**

**0.1 0**  **0.1 0.05**  **Miles North American Datum 1983**  **North Carolina State Plane (3200)**

**Contour Interval 4 Feet** 

# 2 **02/27/2013 1/2 Mile** 

! ? Detection - Level I (TCE)

! ? Detection - Level II (w/TCE)

! ? No Detection of TCED

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Hemphill Rd Little Mountain Rd

Forbes Rd Benfield Rd

Robinson Rd 700 900

800

80 0

800

700 800

800 7

40 760 720 780

680 820 840

860

66

0 880

640 760 680

760 740 780

74

0

720 740 740

720

680 760

720 680 760

760 760 760

740 780

740 760 760

760 Amy Acres

Covington Estates Kensington Estates

Wesley Acres Beverly Acres

**Source: Gaston County, Parcels; Well Sample Locations, NC Division of Waste Management; Contour, NC DOT (Derived from 2007 LIDAR)** 

### HEMPHILL ROAD TCE SITE
**HALF-MILE GROUNDWATER USE MARCH 2012 SAMPLING RESULTS** 

**4. Groundwater Use**

**NC0 002 374 445**

**Gastonia, NC**

**Gaston**

**SMM Fig:** 

**Site:**

**City**

**County:**

**Date:**

**Drawn By:**

**1 inch = 800 feet**

**0.2 0**  **0.2 0.1**  **Miles North American Datum 1983**  **North Carolina State Plane (3200)**

**Contour Interval 4 Feet** 

# 2 **02/07/2013**

! ( **No Detection of TCE**
! ( **Detection - Level I (TCE)**
! ( **Detection - Level II (w/TCE)**
D **Site**
GIT Facility **Community Well**

**Private Well Decommissioned**  **after 1999 TCE Detection** 

**Decommissioned after 1999**  **TCE Detection 1/2 Mile** 

**Falls Dump** March 2012 Drinking Water Sampling Results10 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

1. US Environmental Protection Agency (U.S. EPA); Hazard Ranking System, Final Rule, 55 FR 51532, 1990 and Comprehensive Environmental Response, Compensation, and Liability Act (42 U. S. C. 9601). 1 page. Excerpt. A complete copy of this reference is available at: http://epa.gov/superfund/sites/npl/hrsres/index.htm#HRS Rule

.

2. U.S. EPA; Superfund Chemical Data Matrix (SCDM). January 2004, Revised TCE page da ted March 31, 2012. 4 pages. Excerpt. A complete copy of SCDM is available at: http://epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm

.

3. iTouchMap.com. Latitude and Longitude of a Point, iTouchMap.com. September 25, 2012. 1 page. http://itouchmap.com/latlong.html

.

4. Bartlett, Melanie and Jim Bateson, NC Superfund Section, North Carolina Department of Environment and Natural Resources (NCDENR). Expanded Site Inspection, Hemphill Road TCE, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. September 27, 2012. 290 pages.

5. Bartlett, Melanie and Jim Bateson, NC Superfund Section, NCDENR. Quality Assurance Project Plan, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. March 19, 2012. 2 9 pages.

6. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to File: ESI Sampling Event Trip Report, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. April 2, 2012. 34 pages.

7. Stanley, Jeanette and Jim Bateson, NC Superfund Section, NCDENR. Quality Assurance Project Plan, Rhone-Poulenc Rhodia, Gastonia, Gaston County, NC . EPA ID# NCD 986 182 582. July 22, 2011. 17 pages.

8. NCDENR. Site Inspection Field Notes, Rhone-Poulenc Rhodia, Gastonia, Gaston County, NC . EPA ID# NCD 986 182 582. June 1, 2011 and July 26, 2011. 11 pages.

9. Trapp, Kristin, U.S. EPA. Memo to Carolyn Callihan, Subject: FINAL Analytical Re port, Project: 11-0578, Rhone-Poulenc Rhodia with associated Chain-of-Custodies. August 11, 2011. 103 pages.

10. NCDENR. Field Notes, Hemphill Road TCE, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. August 22-23, 2012. 5 pages.11 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

11. Trapp, Kristin, U.S. EPA. Memo to Carolyn Callihan, Subject: FINAL Analytical Report, Project: 12-0610, Hemphill Road TCE. August 30, 2012. 48 pages.

12. NCDENR. Chain of Custody Record, Project Number: 12-0610. August 23, 2012. 1
pa ge.

13. Bartlett, Melanie, NC Superfund Section, NCDENR. Amended Quality Assurance Project Plan, Hemphill Road TCE, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. August 7, 2012. 29 pages.

14. Parker, Stuart F., NC Superfund Section, NCDENR. Combined Preliminary Assessment/Site Inspection, report, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. October 1999. 286 pages.

15. NCDENR. SI Field Notes, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC

. EPA ID# NC0 002 374 445. May 18, 1999 and June 14-15, 1999. 28 pages.

16. Boyles, P. Sean, NC Groundwater Section, North Carolina Department of Environment, Health, and Natural Resources (NCDEHNR). Report of Investigation, Groundwater Pollution Incident #3858, Gibson Residence, Gaston County, NC. June 1994. 246 pages.

17. NCDENR. NC Public Water Supply Community Well Records. October 3, 2012. 28
pages. https://www.pwss.enr.state.nc.us/NCDWW2/

18. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to File, Subject: Kensington Estates Wells, Hemphill Road TCE, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. October 3, 2012. 1 page.

19. Parker, Stuart F., NC Superfund Section, NCDENR. Memorandum to File: Community Well Contamination, Kensington Estates Subdivision, June 9, 1999. 2 pages.

20. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to file: Census Data [2010]

, Hemphill Road TCE, Gastonia, Gaston County, NC . EPA ID# NC0 002 374 445. July 24, 2012. 3 pages.

21. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to file: Wesley Acres Wells, Hemphill Road TCE, Gastonia, Gaston County, NC. EPA ID# NC0 002 374 445. September 20, 2012. 2 pages.

22. Stanley, Jeanette, NC Superfund Section, NCDENR. Memo to File, Subject: RhonePoulenc Rhodia, Gastonia, Gaston County, NC . EPA ID# NCD 986 182 582. February 28, 2012. 3 pages.12 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

23. U.S. EPA. Superfund Site Information. Site Name: Hemphill Road TCE. Accessed on October 16, 2012. 1 page. http://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0406819

24. DeRosa, Pat, NC Superfund Section, NCDEHNR. Memo to File: Gibson Residence Site, Gastonia, Gaston County, NC . July 28, 1994. 2 pages.

25. DeRoller, Christine, NC Division of Environmental Management. Memo to Pat DeRosa

, NC Superfund Section, Re: Gibson Residence/Gastonia Industrial Trucking, Gaston County, North Carolina. July 29, 1994. 2 pages.

26. Gaughan, Perry, U.S. EPA Emergency Response and Removal Branch (ERRB), Summary of site field activities. October 30, 2009. 39 pages.

27. Heath, Ralph C., U.S. Geological Survey. Basic Elements of Ground-Water Hydrology With Reference to Conditions in North Carolina , U.S. Department of the Interior, OpenFile Report 80-44. 1980. 11 pages. Excerpt. A complete copy of this reference is available at: http://pubs.usgs.gov/of/1980/0044/report.pdf

.

28. Goldsmith, Richard; Milton, Daniel J.; Horton, J. Wright Jr., Geologic Map of the Charlotte 1° x 2° Quadrangle, North Carolina and South Carolina, Map I-1251-E, Mi scellaneous Investigation Series, US Geological Survey, 1988. 9 pages. Available online at http://ngmdb.usgs.gov/Prodesc/proddesc_9068.htm

.

29. NC Department of Natural Resources and Community Development, Geological Survey, Geologic Map of North Carolina, 1985. 3 pages. Available online at http://www.geology.enr.state.nc.us/maps/GeologicMaps/500k_1985_Geo_Map.html

.

30. US Department of Agriculture, Soil Conservation Service, Soil Survey of Gaston County, North Carolina, May 1989. 6 pages. Excerpt. Available online at http://soildatamart.nrcs.usda.gov/Manuscripts/NC071/0/Gaston.pdf

.

31. G eo -Solutions, Inc., Raleigh, NC. Letter reports to the NC Division of Environmental Management (NCDEM) Mooresville Office, RE: Gastonia Industrial Truck, Inc.:

- Soil Contamination Assessment Workplan, recipient Benda Smith, Regional Supervisor

, January 14, 1993.

- Soil Contamination Assessment, recipient Christine DeRoller, Hydrogeologist, March 26, 1993. 25 pages total.

32. Corriher, Thomas W., Gaston County Environment Health. Pollution Incident Report, Incident # 3858, Gibson Well, 4901 Hemphill Road, Gastonia. December 14, 1988. 4
pages.13 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

33. NCDEHNR, Mooresville Regional Office, Division of Environmental Management, Certified letters to Larry Trantham, Gastonia Industrial Truck, Inc.

- Notice of Violation, Gastonia Industrial Truck/Gibson Residence, Incident #3858, November 16, 1992.

- Notice of Violation, Oil Pollution and Hazardous Substances Control Act, Gastonia Industrial Truck, November 16, 1992.

- Notice of Violation, Gastonia Industrial Truck GW Incident No. 3858, November 16, 1992.

- Notice of Requirement, Gastonia Industrial Truck/Gibson Residence, Incident No. 3858, May 19, 1993.

- Groundwater Contamination, Gastonia Industrial Truck GW Incident No. 3858, July 13, 1993. 13 p ages total.

34. The Gaston Gazette , Online News:

- "Contaminated Water Plaguing Neighborhood", June 21, 1999.

- "Kensington Estate Residents Seek Counsel over Water", June 23, 1999.

- "Kensington Closer to New Water Source", July 29, 1999. 6 pages total.

35. Heller, Matt, NC Division of Water Quality – Mooresville Regional Office, NCDENR. R esponse to electronic mail query. Undated. 2 pages.

36. Parker, Stuart F., NC Superfund Section, NCDENR. Memo to File: Telecommunications from Curtis Hopper, Gaston County Environmental Health, Gastonia Industrial Truck – Re -Assessment, Gastonia, Gaston County, NC . February 9, 2000. 1 page.

37. Gaston County Environmental Health, Letter to Kensington Pla ce Subdivision [a.k.a. Kensington Estates], RE: Well Site Approval, November 22, 1996. 3 pages.

38. Parker, Stuart F., and LaMontagne, Dan, NC Superfund Section, NCDENR. Site Re

Assessment, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC. EPA ID# NC0 002 374 445. March 2001. 43 pages.

39. Parker, Stuart F., North Carolina Superfund Section Letter to Matt Heller, NCDENR Mooresville Regional Office, and James Thompson, Gaston County Environmental Health. April 30, 2001. 3 pages.14 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

40. Adams, George, NCDENR Mooresville Regional Office. E-communications:

- Wesley Acres PWS Details/NC – Removal Request – Gastonia Industrial Truck Site, J uly 17, 2009.

- Wesley Acres PWS Details, July 16, 2009.

- Gaston County PWS Referral, August 14, 2009.

- Gastonia Industrial Truck NC0002374445, September 1, 2009.

- Wesley Acres PWS Details/NC – Removal Request – Gastonia Industrial Truck Site, Oc tober 16, 2009. 7 pages total.

41. Bateson, James, Site Evaluation and Removal Branch Head, NC Superfund Section, NCDENR. Removal Request, Gastonia Industrial Truck Site, transmittal to USEPA Emergency Response and Removal Branch (ERRB). July 13, 2009. 1 page.

42. Reference No. Reserved.

43. U. S. EPA. POLREP #1, Gastonia Industrial Trucking, Gastonia, NC. November 4, 2009. 1 page. http://www.epaosc.org/site/polrep_profile.aspx?site_id=5546&counter=12017

44. Parker, Stuart F. and Bateson, James, NC Superfund Section, NCDENR. Site ReAssessment Report, Gastonia Industrial Truck Site, Gastonia, Gaston County, North Carolin a, NC0 002 374 445. January 23, 2012. 24 pages.

45. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to File: Off-site Reconnaissance/Well Survey, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC, NC0 002 374 445. February 6, 2012. 5 pages.

46. U. S. EPA Region 4 SESD. Field Branches Quality System and Technical Procedure for Groundwater Sampling, Number SESDPROC-301-R1. Effective Date: October 28, 2011. 32 pa ges. http://www.epa.gov/region4/sesd/fbqstp/Groundwater-Sampling.pdf

47. North Carolina Administrative Code, Department of Environment and Natural Resources, Division of Water Quality, Title 15A Subchapter 2L, Classifications and Water Quality Standards Applicable to the Groundwaters of North Carolina. January 1, 2010. Excerpt. 25 pages.

48. Stanley, Jeanette and Jim Bateson, NC Superfund Section. Site Inspection, RhonePoulenc Rhodia, Gastonia, Gaston County, NC. EPA ID# NCD 986 182 582. September 20, 2012. 285 pages.

49. Bateson, Jim, NC Superfund Section, NCDENR. E-communication, Subject: Preliminary SI Sample Results – Gastonia Industrial Truck. May 4, 2012. 2 pages.15 HEMPHILL ROAD TCE GASTONIA, GASTON COUNTY, NC LIST OF REFERENCES

50. Bradley, Benjamin L. and Gregory B. Kuntz, Schnabel Engineering. Remedial I nvestigation –

Sampling and Analysis of Surface Water and Sediments, Groundwater Monitoring, and Soil Characterization Borings, Falls Dump, NONCD0000808, 2731 Forbes Road, Gastonia, Gaston County, NC. July 9, 2012; Revised August 15, 2012. 296
pages.

51. Parker, Stuart F., NC Superfund Section, NCDENR. Combined PA/SI Sampling, Gastonia Industrial Truck Site, Gastonia, Gaston County, NC. EPA ID# NC0 002 374 445. Ma y 25, 1999. 9 pages.

52. Rhame, Kenneth, U.S. EPA. E-communication, Subject: Gastonia Industrial Site [ regarding bottled water delivery and water filter testing and sampling]. May 7, 2012. 2
pages.

53. Bartlett, Melanie, NC Superfund Section, NCDENR. Memo to File: Wellhead Protection Areas, Hemphill Road TCE, Gastonia, Gaston County, NC, NC0 002 374 445. January 22, 2013. 3 pages. http://www.ncwater.org/pws/swap/pages/whp.htm

54. U.S. Census Bureau. DP -1. Profile of General Demographic Characteristics: 2000 ; Census 2000 Summary File 1 (SF 1) 100-Percent Data. Gaston County, North Carolina. 3 pages. http://www.census.gov//census2000/states/nc.html ; accessed February 14, 2013.16

1.0 General Site Description

Th e Hemphill Road TCE site is located along Hemphill Road and the surrounding area

, sout heast of Gastonia, NC (Figs. 1-4). Geographic coordinates for the site are 35.197933° north latitude and -81.189852° west longitude. The site coordinates assigned are within the ground
water plume at the approximate center of Hemphill Road itself where it crosses the unnamed tributary (Ref. 3; Figs. 1, 3, 4). The site consists of a contaminated ground water plume with no identified source (Ref. 4, p. 4). The EPA identification number as recorded in the Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) database is NC0002374445 (Ref. 23). The approximate extent of the ground water plume is defined by permanent monitoring wells (R70s7, R70s9, R70s10), Wesley Acres Well #1, the former Kensington Estates Well #1, two private wells located at the end of Benfield Road, and one private well located on Hemphill Road (Ref. 4, pp. 71, 73, 75, 77, 79, 85; Ref. 9, pp. 10, 11; Ref. 11, pp. 10, 16, 31; Fig s. 2-4 ).

Gr ound water contamination in the area is thought to be the result, at least in part, of historical activities that allegedly involved dumping and burning of drums on parcels currently owned by Gastonia Industrial Truck (GIT), Inc. (Ref. 24, p. 2; Ref. 25, p. 2 ). Definitive attribution of the TCE plume at this site to one or more specific sources will not be possible without a ground
water investigation of a scale and scope similar to that employed during a Remedial Investigation. To date, no actual source has been identified through sampling; no actual TCE release has been identified in various investigations through the expanded site investigation (ESI; Ref. 24).

Previous Investigations

The table below lists some of the previous sampling investigations at the Hemphill Road TCE site, including the hazardous substances detected in the samples collected. A detailed history of these investigations is described in Section 3.1.1 of this HRS documentation record.17 Summary of Previous Investigations Agency Investigation Date Samples Collected Hazardous Substances Detected References
GCEHS/ NCDEHNR

- DEM Ground water sampling 1988

- 1993 Ground water Trichloroethene Tetrachloroethene cis

- 1,2

- Dichloroethene Ref. 14, pp. 130

- 255

NCDEHNR

DEM Waste water sampling at GIT waste oil UST /oil

water separator April 1989 Waste water trans

- 1,2

- Dichloroethene Toluene Ethyl benzene Total xylenes Ref. 14, pp. 274

- 28 3

NCDEHNR

- DEM Soil sampling at GIT waste oil above

- ground storage tank September 1992 Soil Tetrachloroethene Ref. 14, pp. 269

- 270

Private Contractor for GIT , Inc. Soil contamination assessment February 1993 Soil Oil & Grease Ref. 31 , pp. 18, 20, 24, 25

NCDEHNR Groundwater Pollution Incident #3858 November 1993 thru March 1994 Soil and ground water Trichloroethene Ref. 16, pp. 89

- 238

NCDENR

- DWM cPA/ SI June 1999 Ground water, soils, and sediment Trichloroethene Tetrachloroethene cis

- 1,2

- Dichloroethene Benzene Ref. 14, pp. 45

- 109

NCDENR

DWQ Ground water sampling July 1999 Ground water Trichloroethene Ref. 14, p. 110

- 127

EPA Emergency Response July 2009 Ground water Trichloroethene Ref. 26, pp. 13

- 39 NCDENR

DWM SI July 2011 Ground water Trichloroethene Ref. 9, pp. 3, 4, 8

- 13, 101

NCDENR

DWM ESI March 2012 Ground water and surface water sampling Trichloroethene Tetrachloroethene cis

- 1,2

- Dichloroethene Ref. 4, pp. 48

- 290

NCDENR

DWM Quarterly filter sampling/ESI follow

- up sampling August 2012 Ground water Trichloroethene Ref. 11, pp. 3

- 48; Ref. 12 ; Ref. 13

GCEHS – Gaston County Environmental Health Services NCDEHNR – North Carolina Department of Environment, Health, and Natural Resources DEM – Division of Environmental Management GIT – Gastonia Industrial Truck, Inc. DWM – Division of Waste Management DWQ – Division of Water Quality EPA – Env ironmental Protection Agency UST – Underground Storage Tank cPA/SI – Combined Preliminary Assessment/Site Inspection SI – Site Inspection ESI – Expanded Site Inspection18

2.2 SOURCE DESCRIPTION

2.2 .1 Source Identification

Number of the Source: 1

Name and description of the source : Contaminated Ground Water Plume with no identified

source.

Location of the source, with reference to a map of the site :

The contaminated ground water plume extends north and west from the GIT facility properties as far south as Wesley Acres well #1 and as far southwest as private wells at the end of Benfield Road and north at private wells along Hemphill Road (Figs. 2-4).

2.2.2 Hazardous Substances Associated with the Source

During the NC DEHNR June 1999 Gastonia Industrial Truck facility combined Preliminary Asse ssment/Site Inspection (cPA/SI) sampling event, ground water samples were collected from the Kensington Estates community drinking water wells, several private drinking water wells, and two permanent monitoring wells (Ref. 14, pp. 45-109). During a NC DE NR sampling event at a nearby, possible site Rhone-Poulenc Rhodia (EPA ID# NCD986182582 ) n ear 297 Telegraph Road (more than 1 mile west/northwest of the Hemphill Road TCE site reference point and unrelated to the Hemphill Road TCE site) in July 2011, two private drinking water wells within one-half mile west/southwest of the Hemphill Road plume’s reference (latitude/longitude) point were sampled (Ref. 9, pp. 3, 4, 8 -13, 101). During the NCDENR March 2012 Gastonia Industrial Truck facilty ESI sampling event, samples were collected from seven community drinking water wells, several private drinking water wells, and nine permanent monitoring wells (Ref. 4, pp. 48, 71 -93 , 278). Dur ing the NCDENR August 2012 sampling event, samples were collected from six private drinking water wells (Ref. 11, pp. 3-48; Ref. 12; Ref. 13). The table below presents the
g round water wells and hazardous substances associated with Source No. 1, a contaminated ground water plume with no identified source.

For more detailed analytical results documenting the ground water plume, see Section 3.1.1 and Figure 3 of this HRS documentation record. Only the most recent sample results for each affected well is included in these results to be most reflective of current conditions. For wells where duplicate samples were collected, lower levels are presented in this HRS documentation record. The hazardous substance TCE is the prominent contaminant of concern and is sufficient to support site listing; therefore, only TCE data are scored in this HRS documentation record.19 Ground Water Wells and Associated Hazardous Substances

Well ID Sample ID Hazardous Substances Well Type References
Kensington Estates Wells #1 & #2 GT

- 015

- PW TCE Community Ref. 14, pp. 86, 96, 99; Ref. 51, p. 6

R70s8 GT

- 001

- GW TCE Monitoring Ref. 4 , pp. 48, 77, 278; Ref. 5, pp. 20, 24
R70s12 GT

- 002

- GW TCE Monitoring Ref. 4 , pp. 48, 75, 278; Ref. 5, pp. 20, 24
R70s10 GT

- 003

- GW TCE Monitoring Ref. 4 , pp. 48, 79, 278; Ref. 5, pp. 20, 24
R70s9 GT

- 005

- GW TCE Monitoring Ref. 4 , pp. 48, 73, 278; Ref. 5, pp. 20, 24
R70s7 GT

- 206

- GW TCE Monitoring Ref. 4 , pp. 48, 85, 278; Ref. 5, pp. 20, 24
GIT Production Well GT

- 012

- GW TCE Supply Ref. 4 , pp. 48, 71, 278; Ref. 5, pp. 20, 24 Wesley Acres Well #1 GT

- 216

- PW TCE Community Ref. 4 , pp. 48, 101, 290; Ref. 5, pp. 20, 25 GT

- 068

- PW TCE Private Ref . 4, pp. 49, 199, 285; Ref. 5, p. 21 GT

- 304

- PW TCE Private Ref. 11, p . 31; Ref. 12, p. 1; Ref. 13, p . 2 GT

- 307

- PW TCE Private Ref. 11, p . 10; Ref. 12, p. 1; Ref. 13, p . 2 GT

- 309

- PW TCE Private Ref. 11, p . 16; Ref. 12, p. 1; Ref. 13, p . 2
RP

- 001

- GW TCE Private R ef. 9, pp. 3, 10, 101; Ref. 7, p. 15
RP

- 002

- GW TCE Private R ef. 9, pp. 3, 13, 101; Ref. 7, p. 15 TCE – Trichloroethene (trichloroethylene)

2.2.3 Hazardous Substances Available to a Pathway

Samples collected from Source No. 1 contain TCE. Source No. 1 consists of a contaminated ground water plume with no identified source underlying the area of Hemphill Road, Gastonia, North Carolina (Ref. 4, pp. 71, 73, 75, 77, 79, 85; Ref. 9, pp. 10, 13; Ref. 11, pp. 10, 16, 31; Ref. 14, p. 99; Figs. 2-4). Analytical results for ground water samples collected from permanent moni toring wells, private drinking water wells, and community drinking water 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. Therefore, a containment factor value of 10, as noted in the table below, was assigned for the ground water migration pathway (Ref. 1, Section 3.1.2.1, Table 3-2).

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: evidence of migration 10 Ref. 1, Section 3.1.2.1, Table 3

- 2; See also Section 3.1.1 of this HRS documentation record. Release via overland migration and/or flood NS

NS – Not scored NA – Not applicable20

2.4.2.1 Hazardous Waste Quantity

2.4.2.1.1 Hazardous Constituent Quantity

The hazardous constituent quantity for Source No. 1 could not be adequately determined according to the HRS requirements; that is, the total mass of all Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) hazardous substances in the source is not known and cannot be estimated with reasonable confidence (Ref. 1, Section 2.4.2.1.1). There are insufficient historical and current data available to adequately calculate the total mass of all CERCLA hazardous substances in the source and the associated releases from the source. Therefore, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous constituent quantity for Source No. 1 with reasonable confidence.

2.4.2.1.2 Hazardous Wastestream Quantity

The hazardous wastestream quantity for Source No. 1 could not be adequately determined according to the HRS requirements; that is, the total mass of all CERCLA hazardous wastestream substances in the source is not known and cannot be estimated with reasonable confidence (Ref. 1, Section 2.4.2.1.2). There are insufficient historical and current data available to adequately calculate the total mass of all CERCLA hazardous wastestream substances in the source and the associated releases from the source. Therefore, there is insufficient information to evaluate the associated releases from the source to calculate the hazardous constituent quantity for Source No. 1 with reasonable confidence.

2.4.2.1.3 Volume

Based on sampling data, a contaminated ground water plume with no identified source underlies the Hemphill Road area of Gastonia, North Carolina. The vertical and horizontal extents 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 waste quantity (HWQ) value for volume (Ref. 1, Section 2.4.2.1.3).

2.4.2.1.4 Area

The area HWQ factor is not evaluated for source type “other” (Ref. 1, 2.4.2.1.4, Table 2-5).

2.4.2.1.5 Source Hazardous Waste Quantity

Value = >0 (Ref. 1, Section 2.4.2.1.5)21 SITE SUMMARY OF SOURCE DESCRIPTIONS

Summary of Source Description

Source No. Source

Hazardous Waste Quantity 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

> - Greater than NS – Not scored

Sum of Source Hazardous Waste Quantity Values = >022

3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 Hydrogeologic Conditions

Ga ston County is located within the Piedmont Plateau physiographic province of NC, lying intermediate between the Coastal Plain physiographic province to the east and the Mountain physiographic province to the west. The piedmont topography consists primarily of well-rounded hills and northeast-southwest trending ridges, with a few more prominent hills referred to as mountains (Ref. 27, pp. 5, 6). Ground surface elevations within a 4-mile radius of the site range fr om 600 feet above mean sea level (MSL) on Crowders Creek, southwest of the site, to 1120 feet

a bove MSL on Jackson Knob, 1.3 miles NE of the site (Fig. 1).

Bedrock in central Gaston County is geologically mapped as part of the Kings Mountain lithotectonic belt, formed primarily during the late Proterozoic Era. The area is underlain by biotite granite of High Shoals Pluton, a mass of igneous rock which intruded the surrounding metamorphic rock formations during the Pennsylvanian Period of the Paleozoic Era (Ref. 28, pp. 2, 3, 7-9; Ref. 29, pp. 1-3).

Bedrock near the land surface weathers to saprolite, an unconsolidated granular material containing ground water in pore spaces. The saprolite layer is hydraulically connected to faults and fractures within the underlying competent bedrock. Locations of steeply-inclined bedrock fractures often correspond with valleys and other eroded topographic lows (Ref. 27, pp. 7, 8). B edrock fractures and the saprolite layer conduct ground water from inter-stream areas to topographic drainage areas, where it discharges to the surface via springs and stream beds. This one unconfined, interconnected saprolite/bedrock aquifer constitutes the primary ground water supply in the Piedmont (Ref. 27, pp. 8 -10 ).

Soil in the area is mapped as Cecil Sandy Clay Loam, 2-8 percent slope, with 8-15 percent slope occurring near surface drainage. This soil type typically consists of a 6-inch surface layer of yellowish-red sandy clay loam, with subsurface soil consisting of red clay and red clay loam to 58 inches depth. Underlying this layer is the loamy saprolite described above to a depth of 80 inches or greater. The soil type reportedly has characteristic water-table and bedrock depths greater than 6 feet (Ref. 30, pp. 3, 5, 6). Hydraulic conductivity of sandy clay soils in the area is estimated to be 10 -6 cm/sec (Ref. 1, Section 3.1.2.3, Table 3-6).

3.0.2 Site-Specific Hydrogeology

Dur ing a soil contamination assessment in early 1993 at the GIT facility by Geo-Solutions, Inc.

, dense saprolite was encountered at a depth of 3 feet (Ref. 31, p. 8). Between November 1993 and Mar ch 1994, soil borings during permanent ground water well installation by NCDEM on the GIT fa cility property and a nearby residential property encountered saprolite overlying weathered
g ranite, with occasional veins of quartz (Ref. 16, pp. 28-51 ).

D uring a 1994 soil and ground water investigation at and near the GIT facility, NCDEM measured ground water depths in each of the 13 monitoring wells installed on the GIT facility properties and a nearby residential property. Ground water depths below land surface ranged23

from 14.76 feet in R70s5 to 36.40 feet in R70s9. The mean ground water depth measured was 29.07 feet (Ref. 16, pp. 25, 26, 240-246; Figure 2). Boring logs and ground water measurements indi cate that ground water exists in bedrock under unconfined (water-table) conditions, under a northwestward hydraulic gradient (Ref. 16, pp. 14, 28 -51, 240-246 ).

During the March 2012 ESI sampling event, NC Superfund Section personnel measured ground water depths in each of the remaining 11 monitoring wells installed on the GIT property. Ground water depths (measured from the top of the metal casings) ranged from 22.0 feet at sample location GT-001-GW (R70s8), located along the westernmost edge of the GIT parcels, to 41.7 fe et at sample location GT-010-GW (R70s16), located along the southeast border of the GIT
pa rcels. One monitoring well, sample location GT-008-GW (R70s13), was completely dry. The water level (39.8 feet) in a second monitoring well, sample location GT-009 -GW (R70s14), was below the level of the passive diffusion sampling device, and no sample was obtained (Ref. 6, pp. 26, 27)

.

Aquifer/Stratum 1

Aquifer/Stratum Name: Saprolite/Bedrock

Type of Aquifer: Non-Karst

Description: In the area of the site, bedrock near the land surface weathers to saprolite, an unconsolidated granular material containing ground water in pore spaces (Ref. 27, pp. 7-8). The saprolite layer generally is hydraulically connected via faults and fractures within the underlying competent bedrock. Ground water in the area originates when precipitation infiltrates the ground surface to the underlying water table. This recharge occurs primarily in inter-stream areas. Bedrock fractures and the saprolite layer conduct ground water from inter-stream areas to topographic drainage areas, where it discharges to the surface via springs and stream beds (Ref. 27, pp. 7-8). This unconfined saprolite/bedrock aquifer constitutes the primary ground water supply in the area of the site (Ref. 27, pp. 7 -10; Ref. 16, pp. 28 -51).24

3.1 LIKELIHOOD OF RELEASE

3.1.1 Observed Release

Aquifer being evaluated: 1 (Saprolite-Bedrock aquifer)

C hemical Analysis:

Since 1988, TCE has been documented in ground water in the area of Hemphill Road, Gastonia (Ref. 4, Appendix A; Ref. 14, pp. 18, Appendix A, Appendix B; Ref. 16, Attachment D). Source No. 1 consists of a contaminated ground water plume with no identified source underlying the area of Hemphill Road, Gastonia, North Carolina (Ref. 4, pp. 71, 73, 75, 77, 79, 85; Ref. 9, pp. 10, 13; Ref. 11, pp. 10, 16, 31; Ref. 14, p. 99; Figs. 2-4).

B ackground and contaminated samples listed in the tables below were collected between June 1999 and August 2012. During the NCDEHNR June 1999 Gastonia Industrial Truck Site cPA/SI sampling event, ground water samples were collected from the Kensington Estates community drinking water wells, several private drinking water wells, and two permanent monitoring wells (Ref. 51, pp. 5, 6, 8). During the NCDENR July 2011 Rhone-Poulenc Rhodia (EPA ID# NCD986182582 ) SI sampling event, two private drinking water wells within one-half mile west/southwest of the Hemphill Road plume’s reference (latitude/longitude) point were sampled (Ref. 7, pp. 12, 15). During the NCDENR March 2012 Gastonia Industrial Truck Site ESI sampling event, samples were collected from seven community drinking water wells, seventy-six private drinking water wells, and nine permanent monitoring wells (Ref. 5, pp. 20, 24). During the NCDENR August 2012 sampling event, samples were collected from six private drinking water wells (Ref. 13, pp. 2, 3).

T he analytical method for volatile organic analysis varied between sampling events, including an unspecified Contract Laboratory Program (CLP) organic purge and trap gas chromatograph/mass spectrometer (P&T GC/MS) method, CLP organic method SOM01.2, and EPA Method 8260C

. However, within a given sampling event, both background and contaminated samples were analyzed using the same method (Ref. 4, pp. 71, 73, 75, 77, 79, 85, 89, 93, 101, 145, 199; Ref. 9, pp. 10, 13, 55; Ref. 11, pp. 10, 16, 22, 31; Ref. 14, pp. 77, 86, 96, 97). Only the most recent

sa mple results for each affected well are included in these results. For wells where duplicate samples were collected, the lower levels are presented in this HRS documentation record.

Background Concentrations

Sample ID Date Time Total Depth (ft) Well Type References

GT

- 003

- PW 6/14/99 19:00 unknown Private Ref. 15, p. 11; Ref. 51, pp. 5, 8

GT

- 010

- GW 3/28/12 10:25 48 Monitoring Ref. 5, pp. 20, 24; Ref. 6, p. 28; Ref. 16, p. 26; Fig. 2
GT

- 013

- PW 3/27/12 12:02 510 Community Ref. 6, p. 18; Ref. 17, p. 5; Figs. 3, 425

Sample ID Date Time Total Depth (ft) Well Type References

GT

- 042

- PW 3/26/12 17:34 95 Private Ref. 5, pp. 21, 27; Ref. 6, pp. 16, 32; Figs. 3, 4
GT

- 301

- PW 8/22/12 11:30 170 Private Ref. 6, p. 33; Ref. 10, p. 1; Ref. 13, pp. 2, 3; Figs. 3, 4
RP

- 018

- GW 7/26/11 14:22 305 Private Ref. 7, pp. 13, 15; Ref. 8, pp. 4, 5

Hazardous Substances in background samples:

Sample ID TCE

( ppb or ug/l) MDL (ppb)/ MRL (ug/l) Reference

GT

- 003

- PW 0.5 0 U 0.50 Ref. 14, pp. 77, 96, 97 GT

- 01 0

- GW 0.50U 0.50 Ref. 4, pp. 48, 89, 278 GT

- 013

- PW 0.050U 0.050 Ref. 4, pp. 48, 93, 280 GT

- 042

- PW 0.050U 0.050 Ref. 4, pp. 49, 145, 282
GT

- 301

- PW 0.50U 0.50 Ref. 11, pp. 3, 22; Ref. 12
RP

- 018

- GW 0.015U 0.015 Ref. 9, pp. 3, 55, 102 Ppb = parts per billion ug = 10 -6 grams U = The analyte was not detected at or above the reporting limit (Ref. 4, p. 51; Ref. 9, p. 4; Ref. 11, p. 4). The compound was analyzed for but not detected. The value reported is the MDL (Ref. 14, p. 97) MDL = Minimum Detection Limit (Ref. 14, p. 97) MRL = Minimum Reporting Limit: Analyte concentration that corresponds to the lowest demonstrated level of acceptable quantitation. The MRL is sample-specific and accounts for preparation weights and volumes, dilutions, and moisture content of soil/sediments (Ref. 4, p. 51; Ref. 9, p. 4; Ref. 11, p. 4).

Contaminated Samples-Ground water

Sample ID Date Time Total Depth (ft) Well Type References

GT

- 015

- PW 6/15/99 11:24 300/366 Community Ref. 15, p. 16; Ref. 18; Ref. 51, p. 6; Figs. 3, 4

GT

- 001

- GW 3/28/12 10:18 33 Monitoring Ref. 5, p p. 20 , 24 ; Ref. 6, p. 27; Ref. 16, p. 25 ; Fig. 2

GT

- 002

- GW 3/28/12 10:13 39 Monitoring Ref. 5, pp. 20, 24; Ref. 6, p. 27; Ref. 16, p. 26 ; Fig. 2

GT

- 003

- GW 3/28/12 8:40 43 Monitoring Ref. 5, p p . 20 , 24 ; Ref. 6, p. 26; Ref. 16, p. 25 ; Fig. 2

GT

- 005

- GW 3/28/12 9:30 55 Monitoring Ref. 5, p p . 20 , 24 ; Ref. 6, p. 28; Ref. 16, p. 25 ; Fig. 226

Sample ID Date Time Total Depth (ft) Well Type References

GT

- 206

- GW 3/28/12 9:47 48 Monitoring Ref. 5, p p . 20 , 24 ; Ref. 6, p. 28; Ref. 16, p. 25 ; Fig. 2

GT

- 012

- GW 3/28/12 9:27 160 Supply Ref. 5, pp. 20, 24; Ref. 6, p. 6; Ref. 16, p. 6 ; Fig. 2

GT

- 216

- PW 3/27/12 13:18 488 Community Ref. 5, pp. 20, 25; Ref. 6, p. 19; Ref. 17, p. 25; Figs. 3, 4

GT

- 068

- PW 3/28/12 11:10 25 0

- 300 Private Ref. 5, pp. 21, 28; Ref. 6, pp. 7, 33; Figs. 3, 4

GT

- 304

- PW 8/22/12 14:45 unknown Private Ref. 6 , p. 32; Ref. 10 , p. 3 ; Ref. 13, pp. 2, 3; Figs. 3, 4

GT

- 307

- PW 8/23/12 11:57 80

- 90 Private Ref. 6 , p. 3 3 ; Ref. 10 , p. 5 ; Ref. 16, p. 7 ; Ref. 13, pp. 2, 3; Figs. 3, 4

GT

- 309

- PW 8/22/12 14:12 80

- 90 Private Ref. 6 , p. 3 3 ; Ref. 10 , pp. 2, 3 ; Ref. 16, p. 7 ; Ref. 13, pp. 2, 3; Figs. 3, 4

RP

- 001

- GW 7/26/11 11:27 unknown Private Ref. 8, pp. 8, 11; Ref. 7, pp. 12, 15; Figs. 3, 4

RP

- 002

- GW 7/26/11 11:00 444 Private Ref. 8, pp. 8, 11; Ref. 7, pp. 12, 15; Figs. 3, 4

Contaminated Samples–Ground water

Hazardous substances found in ground water release samples

Sample ID TCE

( ppb or ug/l) MDL (ppb)/

MRL (ug/l) Reference

GT

- 015

- PW 11.5 0.5 Ref. 14, pp. 86, 96, 99 GT

- 001

- GW 5.8 0.50 Ref. 4 , pp. 48, 77, 278 GT

- 002

- GW 130 5.0 Ref. 4 , pp. 48, 75, 278
GT

- 003

- GW 47 2.0 Ref. 4 , pp. 48, 79, 278
GT

- 005

- GW 210 10 Ref. 4 , pp. 48, 73, 278
GT

- 206

- GW 180 10 Ref. 4 , pp. 48, 85, 278
GT

- 012

- GW 160 8.0 Ref. 4 , pp. 48, 71, 278
GT

- 216

- PW 3.6 0.50 Ref. 4

, pp . 48, 101, 290
GT

- 068

- PW 0. 12 0.05 Ref. 4, pp. 49, 199, 285
GT

- 304

- PW 12 0.50 Ref. 1 1 , p. 31; Ref. 1 2 , p. 1 GT

- 307

- PW 120 1.0 Ref. 1 1 , p. 10; Ref. 1 2 , p. 1 GT

- 309

- PW 110 1.0 Ref. 1 1 , p. 16; Ref. 1 2 , p. 1
RP

- 001

- PW 0.10 0.015 Ref. 9 , pp. 3, 10, 10127 Sample ID TCE

( ppb or ug/l) MDL (ppb)/

MRL (ug/l) Reference

RP

- 002

- PW 1.1 0.015 Ref. 9 , pp. 3, 13, 101 ppb = parts per billion ug = 10 -6 grams MDL = Minimum Detection Limit (Ref. 14, p. 99) MRL = Minimum Reporting Limit: Analyte concentration that corresponds to the lowest demonstrated level of acceptable quantitation. The MRL is sample-specific and accounts for preparation weights and volumes, dilutions, and moisture content of soil/sediments (Ref. 4, p. 51; Ref. 9, p. 4; Ref. 11, p. 4).28

Attribution

Investigation of the ground water contamination began in September 1988, when sampling by the Gaston County Environmental Health Services (GCEHS) detected t ri chloroethene (TCE) exceeding drinking water standards in a private drinking water well located along Hemphill Road (Ref. 14, pp. 136, 138). Re-sampling in November 1988 confirmed TCE contamination in the well (Ref. 14, p. 133). The county filed a Pollution Incident Report with the NC Division of Environmental Management (NCDEM) (Ref. 32, pp. 1-4). Subsequently, in January 1989,

sa mpling by the county health department detected high TCE concentrations in a second private drinking water well located along Hemphill Road and in the GIT facility’s supply well (Ref. 14, pp. 156, 158; Figs. 3, 4).

During the late 1980s and early 1990s, sampling by GCEHS and the NC Division of Environmental Management (NCDEM) detected volatile organic compounds (VOCs) at additional domestic wells (Ref. 14, pp. 171-178, 188, 190, 204, 205, 241-248). A domestic dug

we ll along Hemphill Road (700 f ee t north of GIT ) contained TCE and tetrachloroethene (PCE) (Ref. 14, p. 170, 171). A well along Hemphill Road (0.25 mile north of GIT) contained PCE and 1,1 -dichloroethane (1,1- DC A ) (Ref. 14, pp. 173-174 ; Figs. 3, 4).

In February 1989, a private contractor collected a wastewater sample from the GIT facility. Sample analysis detected toluene, ethylbenzene, xylenes, phenol, phthalates, and possible fuel-oil residue, but no chlorinated solvents (Ref. 14, pp. 280-283). In April 1989, NCDEM collected a water sample from the GIT facility’s underground storage tank (UST)/oil-water separator. This sample contained toluene, ethylbenzene, xylenes, and trans-1,2-dichloroethene, but no other

c hlorinated solvents (Ref. 14, pp. 274-278). In September 1992, NCDEM conducted soil sampling at the GIT forklift repair facility. Sampling detected 1,1,1-trichloroethane

, tetrachloroethene, and bis(2-ethylhexyl)phthalate in soil adjacent to a waste-petroleum

a boveground storage tank (AST) (Ref. 14, pp. 265, 268-270).

I n November 1992, NCDEM sent the GIT facility three Notices of Violation (NOVs) based on the presence of chlorinated solvents in the ground water and in the waste oil AST soil (Ref. 33, pp. 1-8). In May 1993, NCDEM notified the GIT facility that the company would be required to suppl y the two residences across from the facility along Hemphill Road with potable water (Ref. 33, p 10). In response to the NOVs, GIT hired a contractor to conduct a soil investigation (Ref. 33, p. 13). Sampling revealed primarily petroleum contamination, affecting approximately 88 cubic yards of surface soil. Subsurface soil sampling detected no TCE or other volatile organic compounds (Ref. 31, pp. 9, 24, 25). By July 1993, NC DEM’ s attention had turned from the forklift repair facility to the alleged 1950s drum recycling area as a potential source for TCE ground water contamination (Ref. 33, p p

. 11, 12).

Between October 1993 and March 1994, NCDEM completed thirteen borings and installed thi rteen monitoring wells, ranging in depth from 28 to 55 feet, into saprolite/shallow bedrock. Four of the monitoring wells were located within the undeveloped southeast land parcel owned by GIT , and two monitoring wells were installed along the southeast border of th at property. Six monitoring wells were located on the northwest parcel owned by the GIT facility and one moni toring well was installed at the front yard of a nearby residence, across Hemphill Road from the GIT facility (Ref. 16, pp. 11-14, 25-87; Fig. 2 of this HRS documentation record). Ground29

water sampling and elevation data indicated that TCE ground water contamination was concentrated beneath the southeast parcel owned by GIT, but extended northwest beneath the adjacent forklift repair facility toward and across Hemphill Road (Ref. 16, pp. 12, 14, 20, 21, 23, 25, 26)

.

Dur ing well installation, NCDEM performed headspace screening of soil cuttings from the advancing monitoring-well boreholes, in order to delineate possible subsurface soil contamination. Headspace screening for volatile organic compounds was reportedly performed using either a flame ionization or a photoionization meter. When a headspace reading exceeded one meter unit, NC DEM submitted a sample of soil from the corresponding split spoon sampler to the State Laboratory of Public Health, to be analyzed for volatile organic compounds (Ref. 16, p. 8 ). Only one soil boring, collected from sample location R70s15, showed any detectible levels of TCE (Ref. 16, pp. 16-18; Fig. 2). Levels detected in soils at this location were 6.60 microgram per kilogram (ug/kg, 18-20 ft deep), 2.00 ug/kg (33-38 ft deep) and 2.00 ug/kg (38-43 ft deep) (Ref. 16, pp. 11-14, 17, 94, 171-176).

Ar ound June-July 1994, local residents reported that one of the parcels owned by GIT was used during the 1950s for storage and disposal of industrial waste materials. During the early 1950s, 500 -lb. bales of waste cardboard from local cotton mills reportedly were stored on the property. An estimated 1 million pounds of this material accumulated, but was then destroyed by fire (Ref. 25, p. 1). During the 1950s, a former owner allegedly used the southeastern parcel to also recycle several thousand chemical drums. Local residents and the former owner’s son reported that the former owner dumped drum residues onto the ground surface, then rinsed and burned the drums and sold the scrap metal (Ref. 24, p. 2; Ref. 25, p. 2 ). This allegation, however, could not be verified by manifests or sampling.

In May 1999, NC Superfund Section personnel reviewed sample analytical reports on the Kensington Estates community wells, on file at the NC Public Water Supply Section. At the time of file review, Kensington Estates included approximately 38 occupied homes. The results indicated TCE contamination in both of the Kensington Estates community wells, ranging above 10 ug/l and exceeding federal benchmarks and state ground water standards (Ref. 19, p. 1 ).

In June 1999, EPA and NC Superfund Section personnel conducted a combined Preliminary Assessment/Site Inspection (cPA/SI) sampling event to evaluate the exposure hazard to the Kensington Estates residential subdivision, under construction across Hemphill Road from GIT (Ref. 14, pp. 2-4; Ref. 15, pp. 1-28). The two Kensington Estates community drinking-water

we lls were operating within 1000 feet west-southwest from GIT (Figs. 3 and 4 of this HRS documentation record).

During the June 1999 cPA/SI sampling event, the NC Superfund Section collected a total of eleven ground water wells (Ref. 14, pp. 2-4, 14, 26, 27). This included two of the permanent monitoring wells installed on the GIT facility properties : R70s7, the most heavily contaminated monitoring well on the GIT facility properties (GT-002- MW ), and R70s16, a background sample (GT-001-MW); the GIT supply well (GIT-014-P W) ; six private drinking water supply wells along Hemphill Road and nearby Todd Reece Lane (GT-003-PW through GT-012-PW); and point -of-entry for the two Kensington Estates’ community wells (GT-015- PW ). In addition, four soil/sediment samples were collected along the overland flow pathway for the GIT facility parcels30

and an intermittent stream in the area (GT-016-SS thru GT-018-SS, GT-019-SD) (Ref. 14, pp. 14, 26, 27). All cPA/SI samples were submitted to the NC State Laboratory of Public Health. S amples were analyzed for volatile and semi-volatile organic compounds, pesticides and PCBs, and for the eight inorganics regulated under the Resource Conservation and Recovery Act (RCRA) and zinc (Ref. 14, pp. 45 -109).

Samples collected for this June 1999 cPA/SI confirmed the presence of organic contamination beneath the GIT properties and in wells to the west and southwest (Ref. 14, pp. 2- 4) . The sample from monitoring well R70s7 (GT-002 -MW) contained 1255.1 ug/l TCE, 3.6 ug/l PCE, 0.9 ug/l cis-1 ,2-DCE and 1.3 ug/l benzene (Ref. 14, pp. 21, 97, 98). The GIT supply well sample (GT014 -PW) contained an estimated 418 ug/l TCE plus 0.7 ug/l PCE, 0.009 mg/l lead, and 0.57 mg/l zinc (Ref. 14, pp. 21, 55, 99, 100). No contaminants were detected in the monitoring or residential wells located south and east of the GIT properties (GT-001-MW, GT-003-PW, GT

004 -PW, GT-012-PW) (Figure 4 of this HRS documentation record; Ref. 14, pp. 21, 97-100). How ever, the pre-filtration SI sample collected at the private residential well (GT-005-PW)

c ontained 153.1 ug/l of TCE (Ref. 14, pp. 21, 97). The Kensington Estates community well system (GT-015-PW) contained 11.5 ug/l of TCE and 0.766 mg/l of zinc at the point-of-entry to the c ommunity's water lines (Ref. 14, pp. 21, 56, 99).

NC Superfund Section personnel reported the Kensington Estates ground water contamination to the Gaston County Health Department and to the NC Division of Water Quality (NCDWQ; former ly NC DEM) Mooresville Regional Office (MRO). The County and NC DWQ MRO shut down both Kensington Estates community wells, provided a temporary alternative drinking-water suppl y to the residents, and subsequently connected the subdivision to one of two existing community wells at the neighboring Amy Acres subdivision (Ref. 19, p. 2; Ref. 34, pp. 1-3; Ref. 3 6 , p. 1).

In July 1999, sampling by the NC DWQ detected TCE breakthrough at the domestic well carbon filtration units at two residential wells on Hemphill Road. The pre-and post-filtration samples collected from one well on Hemphill Road by NC DWQ reportedly contained 110 ug/l TCE and 150 ug/l TCE, respectively, indicating failure of the filter system (Ref. 14, pp. 113-118). The NC DW Q's pre- and post-filtration samples from the other well on Hemphill Road contained TCE concentrations of 190 ug/l and 200 ug/l, respectively, indicating failure of that system as well (Ref. 14, pp. 122-127).

Based on the number of residents affected by ground water contamination, the 1999 cPA/SI Report recommended further remedial action under CERCLA (Ref. 14, p. 4). However, in March 2001, the NC Superfund Section completed a Site Reassessment Report (SRR) which reversed this recommendation (Ref. 38, p. 10 ). The reversal was made for several reasons. No drums, highly-contaminated soil, or other remediable source media had been identified on the GIT facility properties. In addition, connection of Kensington Estates to the Amy Acres community well system, and maintenance of the carbon units at the two residential wells on Hemphill Road were addressing the existing human exposures identified in the cPA/SI report (Ref. 38, pp. 10, 31 ).

In April 2001, the NC Superfund Section sent a letter to the NCDWQ, MRO and GCEHS. The letter recommended that Amy Acres (and Kensington Estates) subdivision be connected to31

Gastonia municipal water lines, or alternatively, Amy Acres community well system be sampled quarterly or semi-annually for TCE. Also, it was recommended that the two affected residential wells on Hemphill Road be connected to Amy Acres via Kensington Estates, and the domestic well contamination and water usage at an additional residential well along Hemphill Road be further evaluated (Ref. 39, pp. 1-3 ).

Between July and September 2009, the NC Inactive Hazardous Sites Branch (IHSB), MRO notified the NC Superfund Section that TCE contamination existed in additional community wells in the Hemphill Road area. TCE reportedly existed in the two community wells supplying the Wesley Acres subdivision, located directly across Forbes Road, south of Kensington Estates. In 2008, TCE had also appeared in the two community wells supplying the Cedar Grove subdivision, located approximately 1.5 mile southeast of GIT. The NC IHSB, MRO reported that TCE concentrations in the affected wells had been increasing, approaching the 5.0 ug/l federal Maximum Contaminant Level (MCL) (Refs. 2, pp. 4 ; Ref. 40, pp. 2 -4, 6, 7; Figs. 3, 4).

On July 14, 2009, the NC Superfund Section transmitted a Removal Request to U.S. EPA Region 4 Emergency Response and Removal Branch (ERRB), incorporating the above information (Ref. 41, p. 1). The EPA assigned an On Scene Coordinator (OSC) who visited the area in late July 2009. A contractor for the OSC sampled the GIT facility production well, two of the permanent monitoring wells, and three domestic wells along Hemphill Road (Ref. 26, p. 2; Ref. 43, p. 1). The monitoring wells at the GIT forklift repair shop indicated TCE levels at 30 ug/l and 120 ug/l in the monitoring wells and 180 ug/l in the GIT supply well (Ref. 26, pp. 5, 33, 36, 39). Pre-filter

sa mples in wells located at two of the residences showed levels of TCE at 180 ug/l (average, dupli cates of 170 and 190 ug/l) and 140 ug/l, respectively (Ref. 34, pp. 5, 21, 24, 30). Post-filter samples in wells located at the same two residences showed levels of TCE at 220 ug/l and 170 ug/l, respectively (Ref. 26 , pp. 5, 18, 21). EPA assisted with filter replacement at the residences (Ref. 43, p. 1).

In July 2011, the NC Superfund Section conducted an SI sampling event at the Rhone-Poulenc Rhodia (EPA ID# NCD 986 182 582) facility. Sampling included sixteen private wells and one transient non-community drinking water well (Ref. 7, pp. 13, 14; Ref. 8, pp. 1-5; 8-10; Ref. 22, pp. 2-3). All environmental samples for the SI were conducted by NC Superfund Section staff according to section SOPs and U.S. EPA Region IV “Field Branches Quality System and Technical Procedures” (Ref. 7, pp. 8, 9). The specific ground water sampling procedure followed is included as Reference 46. Samples were submitted to a Contract Laboratory Program (CLP) lab. Samples from the SI sampling event were analyzed for volatile organics only (Ref. 9, pp. 1, 3 ).

Two of the wells sampled during July 2011 at the nearby Rhone-Poulenc Rhodia facility SI sampling event (RP-001-GW and RP-002-PW) are located approximately 1⁄2 mile west/southwest of the Hemphill Road plume’s reference (latitude/longitude) point (Figure 3 and Figure 3-B of thi s HRS documentation record). Both wells showed detectible levels of TCE present (Ref. 9, pp. 3, 10, 13, 101). Due to the distance from Rhone-Poulenc Rhodia (great er than 1⁄2 mile southeast) and the presence of Crowders Creek between the two private wells and the Rhone-Poulenc Rhodia facility, TCE present in these two wells is possibly an extension of the Hemphill Road TCE contaminated ground water plume (Ref. 48, pp. 41, 42, 78).32

In January 2012, the NC Superfund completed a second SRR which recommended the Hemphill Road TCE site for further remedial action under CERCLA. This recommendation was based on the presence of TCE contamination in additional community wells, including Wesley Acres, located across Forbes Road from Amy Acres. Also, contaminant breakthrough had occurred at the carbon filter units installed at the two residential wells along Hemphill Road, and additional private wells near the site were showing low-level chlorinated volatile organic compounds (VOCs) or were at risk of contamination (Ref. 44, pp. 1, 11, 12, 17, 18, 23, 24 ).

I n February 2012, the NC Superfund Section conducted a well survey in the areas within approximately 1⁄2 mile of the GIT property. In addition to seven community wells, approximately 150 homes served by private drinking water wells were identified within this 1⁄2 mile radius (Ref. 45, p. 1 ).

In March 2012, NC Superfund Section personnel conducted an ESI sampling event at the Hemphill Road TCE site. During the ESI sampling event, a total of nine monitoring wells, one production well, seven community wells, seventy-six private wells, and five surface water locations were sampled (Ref. 5, pp. 20, 21; Ref. 6, pp. 1-29 ). All environmental samples for the ESI were conducted by NC Superfund Section staff according to section SOPs and U.S. EPA Region IV “Field Branches Quality System and Technical Procedures” (Ref. 5, pp. 16). The specific ground water sampling procedure followed is included as Reference 46. Samples were submitted to a Contract Laboratory Program (CLP) laboratory (Ref. 4, pp. 278-290). Samples from the ESI sampling event were analyzed for volatile organics only (Ref. 4, pp. 45, 48, 49, 50 ).

Analytical results from the permanent monitoring well and the GIT production well indicated elevated levels (greater than three times background) of TCE in five of the nine monitoring wells and the production well. Concentrations ranged from 5.8 ug/l at sample GT-001-GW to 210 at

sa mple GT-005- GW (Ref. 4, pp. 71, 73, 75, 77, 79, 85, 278). TCE detections in all five of these monitoring wells and the production well exceeded the NC ground water standard (3 ug/l), the federal MCL (MCL, 5.0 ug/l), and the federal cancer risk benchmark (1.0 ug/l) (Ref. 2, p. 4; Ref. 47, p p. 17, 20 ; Fig. 2 ).

Of the seven community wells sampled during the March 2012 ESI sampling event, one of these

c ommunity wells, Wesley Acres #1 (GT-016/216-PW), also showed elevated levels of both TCE (3.9/3.6 ug/l) and cis-1,2-DCE (0.10/0.10 ug/l) (Ref. 4, pp. 48, 99, 101, 290). The levels of TCE do exceed both a federal cancer risk benchmark of 1.0 ug/l and the NC ground water standard of 3
ug /l in Wesley Acres #1 (GT-016/216-PW) (Ref. 2, p. 4; Ref. 47, pp. 17, 20 ).

Multiple private wells show elevated levels of TCE, PCE, and/or cis-1,2-DCE. Of these wells wit h detections, two of the wells along Hemphill Road (GT-069/269-PW; GT-070-PW pre-filter

, a nd GT-170-PW post-filter) show elevated levels of TCE (5.1/4.9, 100, and 41 ug/l, respectively) R ef. 4, pp. 48, 50, 67, 69, 203, 205). Three out of four of these TCE values exceed the federal MCL of 5.0 ug/l (Ref. 2, p. 4). All four values exceed a federal health-based benchmark of 1.0 ug/l and the North Carolina ground water standard of 3 ug/l (Refs. 2, p. 4; Ref. 47, pp. 17, 20). TCE detected in two wells ( GT -099 - and GT-102-PW) do es not appear to be associated with the site due to the distance of these two wells from the plume and due to the pattern of intervening multiple clean wells (Figure 3; Figure 3-B; Fig. 4).33

Surface water samples were collected from five locations along the unnamed tributary during the March 2012 ESI sampling event both upstream and downstream of Hemphill Road. Elevated levels of TCE were detected in three downstream surface water samples (GT-021-SW, GT-022

- SW, and GT -023 -SW). GIT-022-SW and GIT-023-SW also showed elevated levels of cis-1,2- dichlor oethene (cis-1,2-DCE), a degradation product of TCE. GT-023-SW, which is located near the northwest corner of the GIT parcels where Hemphill Road crosses the tributary, presented the highest levels of TCE (17 ug/l) and cis-1,2-DCE (2.6 ug/l) (Ref. 4, pp. 17, 33, 108-121, 279).

I n May 2012, the NC Superfund Section notified U.S. EPA Region 4 ERRB of the preliminary

sa mpling results from the March 2012 ESI sampling event. Based on these results, U.S. EPA Region 4 ERRB serviced existing filter systems on two residential wells located along Hemphill Road. In addition, a new filter system was added to an additional drinking water well located along Hemphill Road (Ref. 49, p. 1; Ref. 52, pp. 1, 2 ).

In May 2012, Falls Dump (NC ID# NONCD0000808, adjacent to Kensington Estates) was evaluated under the NC IHSB, Pre-Regulatory Landfill Program. Samples included five soil borings, five temporary wells, three surface water and five sediment samples (Ref. 50, pp. 4, 5, 6). Onl y two sample locations (SW-1 and SW-3) showed any detectible quantities of chlorinated solvents (Ref. 50, pp. 4, 5, 8-11). TCE was detected only in surface water along the unnamed tributary at levels of 6.6 and 1.2 ug/l, respectively (Ref. 50, pp. 10, 14, 16, 68, 78, 82, 98).

In August 2012, NC Superfund Section personnel conducted follow-up sampling at the Hemphill Road TCE site. Samples included ground water from six private drinking water wells, including pre- and post-filter samples from three wells along Hemphill Road (Ref. 10, pp. 1-5; Ref. 13, pp. 1, 2). Pre-filter samples at all three wells showed elevated levels of TCE (12, 120, and 110 ug/l, respectively) (Ref. 11, pp. 10, 16, 31; Ref. 12, p. 1). The level in all three wells pre-filter exceeded the federal MCL of 5.0 ug/l (Ref. 2, p. 4). Post-filter samples showed results of nondetect, indicating the filters are working (Ref. 10, pp. 2, 3, 5; Ref. 11, pp. 3, 13, 19, 37; Ref. 12, p. 1 ; Ref. 13, pp. 2, 3 ).

I n conclusion, the TCE contamination in this area of Gastonia, North Carolina, has been determined to be a ground water plume with no identified source. No specific sources or TCE releases have been adequately identified to date.

Hazardous Substances in the Release

TCE

Ground Water Observed Release Factor Value: 55 0

3.1.2 Potential to Release

Potential to release was not evaluated for the Saprolite-Bedrock aquifer because an observed release has been documented (see Section 3.1.1 of this HRS documentation record).34 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 the table below. The combined 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).

Hazardous Substance Source

No. Toxicity Factor Value Mobility

Factor Value Toxicity/

Mobility Reference

TCE 1 1000 1 1000 Ref. 2 , p. 4
TCE – trichloroethene (trichloroethylene)

3.2.2 Hazardous Waste Quantity

Source Number Source Hazardous

Waste Quantity Value ( Section 2.4.2.1.5) Is source hazardous Constituent quantity data complete? (yes/no)
1 >0 No

The hazardous constituent quantity for Source No. 1 is not adequately determined. For a migration pathway, if the hazardous constituent quantity is not adequately determined for one or more source, assign a factor value as follows: If any target for that migration pathway is subject to Level I or Level II concentrations, assign either the value from HRS Table 2-6 or a value or 100

, whichever is greater (Ref. 1, Section 2.4.2.2). Since targets for the ground water migration pathway are subject to Level I and Level II concentrations (see Section 3.3.2.2. and 3.3.2.3. of this HRS documentation record), the hazardous waste quantity factor value assigned is 100.

3.2.3 Waste Characteristics Factor Category Value

Hazardous Waste Quantity Factor Value: 100

Toxicity/Mobility Factor Value: 1,000

HWQFV x TMFV: 100 x 1,000 = 100,000

Waste Characteristics Factor Value (Ref. 1, Table 2-7): 1835

3.3 Targets

Two community wells serving Kensington Estates were taken offline in 1999 due to TCE contamination (Ref. 14, pp. 86, 96, 99), which exceeded the MCL of 5.0 ug/l (Ref. 2, p. 4), and

c onnected to the nearby Amy Acres community water system (Ref. 19, p. 2; Ref. 34, pp. 1-3; Ref. 3 5 , p. 1; Ref. 36 ). Wesley Acres Well #1 has been impacted by TCE (Ref. 4, pp. 48, 101, 290) and continues to be in use (Ref. 17, pp. 22, 24, 25). The levels detected have not exceeded the MCL; however, the levels do exceed the Cancer Risk Screening Concentration of 1.0 ug/l (Ref. 2, p. 4).

Private wells at three houses along Hemphill Road have TCE contamination (Ref. 11, pp. 10, 16, 31; Ref. 12, p. 1) which exceeds the MCL (Ref. 2, p. 4). The well at one house on Benfield Road has TCE contamination (Ref. 9, pp. 3, 13, 101) that do es not exceed the MCL but do es exceed the Cancer Risk Screening Concentration (Ref. 2, p. 4). Wells at a second house along Benfield Road and an additional house on Hemphill Road each have an observed release of TCE (Ref. 4, pp. 49, 199, 285; Ref. 9, pp. 3, 10, 101), al though the levels do not exceed either the MCL or the Cancer Risk Screening Concentration (Ref. 2, p. 4).

Several community and private wells are located within a 4-mile radius of the site (Figure 1) ; howe ver, potential contamination was not scored in this HRS documentation record.

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).

See Section 3.3.2.2 of this HRS documentation record for all ground water wells evaluated at Level I concentrations.

3.3.2 Population

At the time when the two Kensington Estates community wells were taken offline due to TCE contamination (Ref. 14, pp. 86, 96, 99; Ref. 19, p. 2; Ref. 34, pp. 1-3; Ref. 35 , p. 1; Ref. 36), there were approximately 38 homes occupied and served by the two wells (Ref. 19, p. 1). Based on the 2000 census average for Gaston County of 2.53 persons per household, this gives a total population of approximately 96 .14 people for Kensington Estates impacted at well closure in 1999 (Ref. 54, p. 2 ).

Wesley Acres community water system serves a total of 168 people (Ref. 17, p. 22). Wesley Acres is a blended system, consisting of only two wells, with no surface water intakes or purchased water (Ref. 17, p. 22; Ref. 21, p. 1). Based on actual usage, Wesley Acres Well #1 provides an average of 24.4% of the water used in the Wesley Acres community water system (Ref. 21, pp. 1, 2). Therefore, a population of 40.99 people is assigned to Wesley Acres Well #1.

Populations for the individual private wells were provided by the residents of the homes for which the w ells serve (Ref. 6, p. 33; Ref. 22, p. 2).36

Level of Contamination

3.3.2.2 Leve l I Concentrations

Level I Well Population Reference
GT

- 015

- PW (Kensington Estates Wells #1 & #2) 96 .14 Ref. 19, p. 1; Ref. 20, pp. 1, 2

GT

- 216

- PW (Wesley Acres Well #1) 40 .99 Ref. 17, p. 22; Ref. 21, p p . 1 , 2

GT

- 304

- PW 3 Ref. 6, p. 33
GT

- 307

- PW 2 Ref. 6, p. 33
GT

- 309

- PW 4 Ref. 6, p. 33
RP

- 002

- PW 2 Ref. 22, p. 2

9 6 .14 + 4 0 .99 + 3 + 2 + 4 + 2 = 148.13

1 48.13 * 10 = 1 4 81.3 (Ref. 1, Section 3.3.2.2)

Level I Concentration Factor Value: 1481 .3

3.3.2.3 Level II Concentrations

Level II Well Population Reference
GT

- 068

- PW 3 Ref. 6, p. 33 RP

- 001

- PW 2 Ref. 22, p. 2

Level II Concentration Factor Value: 5 3.3.2.4 Potential Contamination

Not Scored–While several other private and community wells are located within a 4 mile radius of the site (Figs. 1, 3, 4), they have not been impacted and do not contribute significantly to the site score.

3.3.3 Resources

No target well is documented to be used for any purposes identified in Ref. 1, Section 3.3.3.

3.3.4 Wellhead Protection Area

The ground water plume is not located within a Wellhead Protection Area (Ref. 53, p. 1 ). No designated Wellhead Protection Area is located within 4 miles of the plume (Ref. 53, p. 1; Figure 1 ).