HAZARD RANKING SYSTEM (HR S) DOCUMENTATION RECORD COVER SHEET

Name of Site: 700 South 1600 East PCE Plume

EPA ID No.: UTD981548985

Contact Person : U.S. Environmental Protection Agency, Region 8 Sabrina Forrest, N ational P riorities L ist Coordinator

1595 Wynk oop Street , Mail Code: 8EPR -B Denver, Colorado 80202

- 1129 (303) 312

- 6484

Pathways, Components, or Threats Not Scored :

The surface water migration, soil exposure, and air migration pathways were not scored in this Hazard Ranking System (HRS) documentation record because they are not expected to significantly contribute to the overall site

score.HRS Documentation Record 09/2012 1 700 South 1600 East PCE Plume UTD981548985 HRS DOCUMENTATION RECORD

Name of Site: 700 South 1600 East PCE Plume

EPA Region: 8

Date Prepared: September 2012

Str eet Address of Site *: I ntersection of 700 South & 1600 East

City, County, State , ZIP Code : Salt Lake City, Salt Lake County, Utah 84102

General Location in the State: North central

Topographic Map: Fort Douglas, Utah

Latitude *: 40 .75 3938 **°** North Longi tude *:

- 111.848022 **°** West (Figure 1)

The location given above is the approximate center of the current known extent of ground water contamination.

Ground water Pathway 100.00 Scores :

Air Pathway NS Soil Exposure Pathway NS Surface Water Pathway NS HRS Site Score 50.00

Note: NS = Not scored

* The street address, coordinates, and contaminant locations presented in this HRS documentation record identify the general ar ea 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 haza rdous substances; thus, the focus i s on the release, not precisely delineated boundaries. A site is defined as where a hazardous substance has been “deposited, stored, placed or otherwise come to be located.” Generally, HRS scoring and the subsequent listing of a rele ase merely represent th e 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 informati on is developed as to where the contamination has come to be located.HRS Documentation Record 09/2012 2 700 South 1600 East PCE Plume UTD981548985 WORKSHEET FOR COMPUTING HRS SITE SCORE

S S 2

1. Ground water Migration Pathway Score (S gw ): 100 (from Ref.1, Table 3

- 1, line 13) 10,000

2a. Surface Water Overland/Flood Migration Component : NS (fr om Ref.1, Table 4

- 1, line 30) NS

2b. Ground water to Surface Water Migration Component : NS (from Ref.1, Table 4

- 25, line 28) NS

2c. Surface Water Migration Pathway Score (S sw ): NS ( Enter the larger of lines 2a and 2b as the pathway score ) NS

3. Soil E xposure Pathway Score (S s ): NS (from Ref.1, Table 5

- 1, line 22) NS

4. Air Migration Pathway Score (S a ): NS (from Ref.1, Table 6

- 1, line 12) NS

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

6. HRS Site Score : Divide the value on line 5 by 4 and take the square root : 50.00

Note: NS = Not ScoredHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 3 TABLE 3 -1 (Ref. 1) GROUND WATER MIGRATION PATHWAY SCORE SHEET Aquifer Evaluated: ‘Principal Aquifer’

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 100

5. Hazardous Waste Quantity a 100
6. Waste Characteristics 100 10 Targets

7. Nearest Well b 45
8. Population
8a. Level I Concentrations b 0
8b. Level II Concentrations b 9,051
8c. Potential Contamination b 2 54 8d. Population (lines 8a + 8b + 8c) b 9,305
9. Resources 5 0
10. Wellhead Protection Area 20 20
11. Targets (lines 7 + 8d + 9 + 10) c 9,370
Ground W ater Migration Score for an Aquifer

12. Aquifer Score [(lines 3 x 6 x 11)/82,500] 100 100

Ground W ater Migration Pathway Score

13. Pathway Score (SW gw ), (highest value from line 12 f or all aquifers evaluated) c 100 100

Notes:

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

c = Do not round to the nearest integer NS = Not scoredApproximate Extent of Known Ground Water Contamination

Fort Douglas 7.5' USGS Quad

Sugar House 7.5' USGS Quad PCE Disposal Point to Sewer

Latitude: 40.754 o N Longitude: -111.848 o W VA Medical Center Building 7

Sanitary Sewer Line

UOS - START3 700 SOUTH 1600 EAST PCE PLUME SITE SALT LAKE CITY, UTAH
Figure 1: 700 South 1600 East PCE Plume Location
07/2012

0 0.25 0.125 Miles USGS Topographic Map1998 Fort Douglas 7.5' Quad Sugar House 7.5' Quad 

#  ́ ^ _

Salt Lake City


## U t a h U t a h

Data: Sanitary Sewer Line location: Ref. 8, pp. 39, 40 PCE Disposal Point: Ref. 8, pp. 43 - 45 Contamination extent: Refs. 26, 27, 28 

### Legend

VA Medical Center Building 7
PCE Disposal Point to Sewer
Sanitary Sewer Line
Approximate Extent of Known Ground Water ContaminationAuthor: skane Date/Time: Friday, July 13, 2012 1:27:54 PM File: T:\START3\East Side Springs HRS\GIS\Maps\Figure1.mxd

### Sunnyside Ave. Sanitary Sewer Line Building 7 PCE Disposal Point to SewerAuthor: ND_Williams Date/Time: Thursday, July 05, 2012 10:49:12 AM File: T:\START3\East Side Springs HRS\GIS\Maps\Reference 4.mxd



### 700 SOUTH 1600 EAST PCE PLUME SALT LAKE CITY, UTAH Figure 2: Source Location 07/2012 UOS - START3

0 125 250 

#  ́

Feet
Data: Sanitary Sewer Line location: Ref. 8, pp. 39, 40 Disposal Point to Sewer: Ref. 8, pp. 43 - 45 Datum/Projection: NAD 1983 UTM Zone 12N Maps: Bing Maps 2011

# ^ ^ ^ _ _ _ SL20 1123 E. Alpine

ESS-SW-16 SL30 1205 E. Gilmer

Path: T:\START3\East Side Springs HRS\GIS\Maps\Figure3.mxd 700 SOUTH 1600 EAST PCE PLUME
Figure 3. Ground Water Observed Release and Location of PCE-Contaminated Springs

Maps: Bing Maps 2011 Projection System: NAD 1983 State Plane Utah Central FIPS 4302 Feet 

#  ́ Data: Well and spring locations: Refs. 20, 21, 22, 26, 27, 28, 45 PCE disposal point to sewer: Ref. 8, pp. 43 - 45 Sanitary sewer line location: Ref. 8, pp. 30, 40 UOS - START3 07/2012

0 250 500 125
Feet 1156 E. 900 S. 

# & -



# ^^ ^ ^ ^ ^

__ _ _ _ _ PCE Disposal Point to Sewer SLCWS Well #18



## East Side Springs Mount Olivet Cemetery Irrigation Well

VA Medical Center Building 7

Sanitary Sewer Line
ESS-SW-15 SL62 1127 E. Sunnyside SL18 1143 E. Sunnyside

SL23 SL25 1156 E. 900 S. ESS-SW-17 1115 E. Sunnyside EPA-MW-03

EPA-MW-01D/S EPA-MW-02

EPA-MW-04

EPA-MW-06 EPA-MW-05


### Ground Water

Flow Direction 

# y ! . 

# & - Mt Olivet Well 

## ! . SLCWS Well #18 

# ^ _ PCE-Contaminated Spring

EPA Wells - 1998

Sanitary Sewer Line

VA Medical Center Building 7

Observed Release to Ground Water sample ID address Fort Douglas Military Installation University of Utah

VA Medical Center

Salt Lake City Sports Complex Utah Army National

Guard East High School Mount Olivet Cemet e ryHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 7 REFERENCES

Ref. No. Reference description

1. U.S. Environmental Protection Agency (EPA), Hazard Ranking System (HRS), 55 Federal Register 51532. December 14, 1990. Excerpt . C over page only. A complete copy is available at: http://www.epa.gov/superfund/sites/npl/hrsres/rule/part1_2.pdf and in the Region 8 Docket.

2. EPA. Superfund Chemical Data M atrix (SCDM)

. January 2004

. Update d December 2011 and – Volatile Substances, March 31, 201 2. 12 pages. E xcerpt. A copy of the volatile substances update is available at: http://www.epa.gov/superfund/sites/npl/hrsres/tools/volatile

- substances

- factor

values.pdf

. A complete copy of SCDM is available at: http://epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm

3. Reference reserved.

4. Reference reserved.

5. Utah Geological Survey (UGS). 2012. Evaluating the Seismic Relation between the West Valley Fault Zone and Salt Lake City Segment of the Wasatch Fault Zone, Salt Lake Valley, Utah. By Michael D. Hylland et. al. In Utah Geological Survey, Survey Notes, Volume 44, Number 2. May 2 012. Excerpt. 3 pages.

6. Toeroek Associates, Inc. 2012. Updated Draft Business Survey dated April 30, 2012

, East Side Springs Site. Written by Lindsay Garner, Project Manager, Toeroek Associates, Inc. 60 pages.

7. EPA. CERCLIS Public Access Database. Search fo r EPA ID: UTD981548985 (700 South 1600 East PCE Plume) and EPA ID: UTN000802825 (East Side Springs). 2 pages. Accessed on July 10

, 2012. Accessed on

- line at: http://cumulis.epa.gov/supe rcpad/cursites/srchsites.cfm

8. U.S. Department of Veterans Affairs (VA)

. 2005. Response to EPA Letter July 12, 2005 request for Information Pursuant to Section 104 of CERCLA for the Mount Olivet Cemetery Plume Site

. Written by James R

. Floyd , Director

. Date d September 9, 2005. Excerpt (original copy contains oversized construction drawings). 47 pages.

9. Utah Department of Health (UDH) , Division of Environmental Hea lth. 1991. Memorandum to File regarding Contamination of the Mount Olivet Cemetery. Written by Dennis Fredrick, Environmental Engineer, UDH. Dated February 28, 1991. 3 page s.

10. State Coalition for Remediation of Drycleaners. 2010. Conducting Contamination Assessment Work at Dry Cleaning Sites. Revised October 2010. By Bill Linn, et. al. Excerpt. 16 pages. A complete copy is available at: http://www.drycleancoalition.org/download/assessment.pdf

11. EPA. 1998. Cleaner Technologies Substitutes Assessment: Professi onal Fabricare Processes. EPA 744 -B- 98

- 001. June 1998. Excerpt. 7 pages. A complete copy is available at: http://www.epa.gov/dfe/pubs/garment/ctsa/fabricare.pdf

12. IHI Environmental. 2007. Soil Gas Investigation R eport. Sanitary Sewer Lateral, VASLCHCS Building 7 to Sunnyside Avenue, Salt Lake City, Utah. Prepared for VASLCHCS. Dated December 20, 2007. Excerpt. 20 pages.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 8 13. URS Operating Services ( UOS ) (on behalf of the EPA Superfund Technical Assessment and Response Team (START) program)

. 1996. Field Activities and Analytical Results for Soil Gas Sampling at the Mount Olivet Cemetery Plume, Salt Lake City, Utah (TDD #9609

- 0003), by Barry Hayhurst. December 6, 1996. 16 pages

.

14. Utah Department of Environmental Quality (UDEQ). 2006. Affidavits collected from Rick Bright, Salt Lake City Department of Public Utilities ( SLCDPU ) Waste/Stormwater Collections Manager (collected on 2 June 2006), and Tom Tabish, SLCDPU Lift Station Supervisor (collected on 13 June 2006), regardi n g observations of dry cleaning solvent within the sanitary sewer line leading from Building 7 of the VA Medical Center in the early to mid

- 1980’s. 6 pages.

15. SLCDPU . 2012. Screen shots from a video survey recorded by SLCDPU of the sewer line leading from Bu ilding 7 of the VA Medical Center. Survey p erformed December 17, 2003. Reference includes 2 page s of figure s entitled Mt. Olivet Cemetary [sic] Plume Site Well a nd Manhole Locations

, dated December 23, 2003 ; and a 2 page email chain concerning the survey between Jeff Miller ( EPA START ) and Chad Gilgen (UDEQ), dated March 15

- 19, 2012. 16 total p ages

.

16. California Environmental Protection Agency Air Resources Board

. 1996. Curriculum for the Environmental Training Program for Perchloroethylene Dry Cleaning Opera tions

. April 1996. Excerpt. 5 p ages. A complete copy is available at: http://www.arb.ca.gov/training/etpmanul.pdf

17. P.M. Santi, et. al. 2005. Investigating cross

- contamination of aquifers. Journal o f Hydrogeology. Volume 14, p. 51

- 68. Excerpt. 6 pages. A complete copy is available online at: http://inside.mines.edu/~psanti/paper_pdfs/Cross%20contamination.pdf

18. Ecology and Environment, Inc. (E & E) (on behalf of the EPA Superfund Technical Assessment a nd Response Team (START) program

. 1995. Analytical Results Report, Mt. Olivet Well Site, Salt Lake City, Utah. TDD# TO8

- 9505

- 012. Prepared for USEPA Region VIII, Denver, CO, Steve Hawthorn, On

- Scene Coordinator. By D’Arcy Straub. Dated June 2, 1995. 13 pages.

19. EPA START ( E & E ). 1995. Analytical Results Report, Mt. Olivet Well Site, Salt Lake City, Utah. TDD# TO8

- 9505

- 012. Prepared for USEPA Region VIII, Denver, CO, Steve Hawthorn, On

- Scene Coordinator. By D’Arcy Straub. Dated August 2, 1995. Reference i ncl udes 3 page memorandum dated October 4, 1995 from John Noto (E&E) to Steve Hawthorn (USEPA) with corrected Figure 1 and Table 1 for the report. 14 total pages.

20. EPA START ( UOS ). 1999. Site Activities Report, Mount Olivet Cemetery, Salt Lake City, Salt Lake County, Utah. TDD No. 9803

- 0014 . B y John Noto. Dated May 20, 1999. Reference includes data validation report. 129 pages

.

21. EPA START ( UOS ). 2000. Supplement to the Site Activities Report. Mt. Olivet Cemetery, Salt Lake City, Salt Lake County, Utah. TDD No. 9803

- 0014. By John Noto. Dated March 14, 2000. Excerpt. Reference includes data validation report

. 53 pages

.

22. UDEQ

. 2000. Analytical Results Report, Mount Olivet Cemetery Plume, Salt Lake County, Utah (UTD981548985). B y Neil B Taylor. Dated August 8, 2000. Excerpt. 92 pages.

23. UDEQ. 2004

- 2005

. Analytical Results Report, Mount Olivet Cemetery Plume, Soil Sampling Event

– June 2004, Groundwater Sampling Event – October 2004. Dated November 11, 2004. Author unknown. Draft (pages 7

- 10 appear to be from a report regarding the Bountiful Woods Cross PCEHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 9 site)

. Reference includes analytical results

, under separate cover, and 2005 data validation report

. 73 total pages.

24. USGS. 2004

- 2005. Compilation of documents from USGS including email between Susan Thiros (USGS) and Jerald Cross (EPA) dated November 16, 2004; and USGS PowerPoint slide shows regarding site

- specific geologic stratigraphy and analytical results from sampling event conducted February 2005. Various dates. Excerpt. 33 total pages.

25. UDEQ. 2005. Salt Lake Cit y Water System (SLCWS) Well [#18] Analytical Sampling Results Mount Olivet Ground Water Plume, Salt Lake City, Utah, by Chad Gilgen. Dated November 18, 2005. Reference includes 2 pages of field notes from sampling logbook. 7 pages

.

26. EPA START ( UOS ). 2005. Documentation of ground water sampling conducted by EPA START in October 2005

. Reference includes 9 pages from sampling event logbook, by Bryan Williams ( EPA START ) and data validation report. 54 total pages.

27. SLCDPU

. 2010

- 2011 . Compilation of documents fro m SLCDPU regarding sampling of East Side Springs, including a copy of a media advisory regarding the oil spill in Red Butte Canyon (available online at: http://www.slcgov.com/oilspill/), copies of laboratory analytical data from the Chemtech

Ford Laborator ies, Murray, Utah, various dates; and one figure from the SLCDPU entitled Parcels where SLCDPU Samples were taken with detected PCE – 2010, by Tammy Wambean, SLCDPU

. 47 total pages.

28. UDEQ. 2012

. Site Investigation Analytical Results R eport. East Side Sp r ing s, Salt Lake County, Utah. UTN000802825

. May 2012. Excerpt. 15 5 pages.

29. MWH Americas, Inc. (MWH). 2012. Draft Hydrogeological and Groundwater Model Summary Report for: Culinary Water Supply Protection Project at Salt Lake City’s Drinking Water Well #18 (als o referred to as the 500 South Well). Prepared for SLCDPU

. Dated February 8, 2012. Excerpt. 74 pages.

30. EPA. 1998. EPA Office of Research and Development. Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Ground Water, EPA/600 /R

- 98/128. September 1998. Excerpt. 2 pages. A complete copy is available at: http://www.epa.gov/nrmrl/pubs/600R98128/protocol.pdf

31. EPA START ( UOS ). 2012. Memorandum of a telephone convers ation between Jeff Miller, EPA START and Tom Tabish, Lift Station Maintenance Supervisor, Salt Lake City Department of Public Utilities (801) 952

- 9036, regarding the absence or presence of a liner beneath the sewer line leading from Building 7 of the VA Medical Center in Salt Lake City. 1 page. Dated March 26, 2012.

32. Victor J. Izzo. 1992. Dry Cleaners – A Major Source of PCE in Ground Water. Dated March 27, 1992. California Regional Water Quality Control Board, Central Valley Region. 2 5 pages. A vailable onli ne at: http://www.waterboards.ca.gov/rwqcb5/water_issues/site_cleanup/dry_cleaner_rpt.pdf

33. Thomas K. G. Mohr. Undated. Study of Potential for Groundwater Contamination from Past Dry Cleaner Operations in Santa Clara County, Final Draft. Excerpt. 6 pages. A complete copy is available at: http://www.swrcb.ca. gov/sanfranciscobay/publications_forms/documents/SCVWD_Study/Study.pdfHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 10 34. UDEQ. Various dates. Various records from the UDEQ Division of Environmental Response and Remediation regarding regulation of petroleum leaks from underground storage tanks (USTs) loca ted within the area of the 700 South 1600 East P CE Plu me. Reference includes two maps showing location of previously leaking USTs. 36 pages. All records and maps available online at: http://mapserv.utah.gov/Deq

35. U tah National Guard (UNG). Various dates. Correspondence between the Utah National Guard (UNG) and the UDEQ and EPA regarding activities conducted at the Utah Army National Guard (UANG) Organizational Maintenance Shop (OMS) 5 and Combined Support Maintenanc e Shop (CSMS), located at 720 Guardsman Way (aka 1543 Sunnyside Avenue), Salt Lake City. Correspondence includes the UNG response to EPA’s R equest for Information Pursuant to Section 104 of CERCLA for the UNG OMS

- 5 and the CSMS. Written by Robert K. Price, State Environmental Specialist. Dated July 30, 1996. Excerpt

. 13 pages.

36. UDEQ. 2009. Expanded Site Inspection, Analytical Results Report, Sugar House Park Plume, Salt Lake County, Utah. EPA ID: UT0000987776. Division of Environmental Response and Remediati on. By J. D. Keetley. Dated January 5, 2009. Excerpt. 9 pages.

37. Google. 2012. Map showing dry cleaners locat ed within 1.8 miles of known area of PCE contaminated ground water at the 700 South 1600 East PCE Plume site

. 1 page. Source: http:// maps.google.co m/

38. USGS. 2003. Hydrogeology of Shallow Basin

- Fill Deposits in Areas of Salt Lake Valley, Salt Lake County, Utah. USGS Water

- Resources Investigations Report 03

- 4029. By Susan A. Thiros. Excerpt. 10 pages. All annotations within reference (pages 5, 6, 9, 10) obtained from References 20

- 22, 26

- 28, 45

. A complete copy is available at: http://pubs.usgs.gov/wri/wri034029/pdf/wri034029.pdf

39. USGS. 2009. Surficial Geologic Map of the Salt Lake City Segment and Parts of Adjacent Segments of the Wasatch Fault Zone, Davis, Salt Lake, and Utah Counties, Utah (digitized from USGS Miscellaneous Investigations Series Map I

- 2106, 1992), by Stephen F. Personius and William E. Scott. Excerpt (orig inal source c opy is oversized). 5 pages. All annotations within reference (page 2) obtained from References 20

- 22, 26

- 28, 45

. A complete copy is available at: http://geology.utah.gov/online/m/m

- 243.pdf

40. Utah Division of Water Rights (UDWR). 2012. Various information downloaded from the UDWR
map server. Includes well logs and map s identifying location of wells

. 14 pages. All annotations within pages 1 -9 obtained from database

. Location : http://maps.waterrights.utah.gov/

41. USGS. 2010. Conceptual Understanding and Groundwater Quality of Selected Basin

- Fill Aquifers in the Southwestern United States. Section 2.

- Conceptual Understanding and Groundwater Quality of the Ba sin

- Fill Aquifer in Salt Lake Valley, Utah. By Susan A

. Thiros. Professional Paper 1781. Excerpt. 12 pages. Pages 6 and 10 modified ; sources of information include References 26

- 28 and http://mapserv.utah.gov/DEQ . A complete copy of Reference 41 is available at: http://pubs.usgs.gov/pp/1781/

42. UGS. 2009. Ground

- Water Quality Classification for the Principal Basin

- Fill Aquifer, Salt Lake Valley, Salt Lake County, Utah. Open File Report 560. By Janae Wallace an d Mik e Lowe. Excerpt. 5 pages. A complete copy is available at: http://geology.utah.gov/online/ofr/ofr

- 560/ofr

- 560.pdfHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 11 43. EPA

. 2011. Superfund Analytical Services, Contract Laboratory Program ( CLP). SOM01.2 Volatile Target Compound List and Corresponding CRQLs. 1 page. Source: http://www.epa.gov/superfund/programs/clp/som

- vtarget.htm

44. EPA. 1996. Using Qualified Data to Docu ment an Observed Release and Observed Contamination. EPA540 -F- 94

- 028. OSWER 9285.7

- 14FS. November 1996. 18 pages.

45. SLCWS and UDEQ

. Various dates. Electronic and postal mail correspondence

, and historic

a nalytical results from compliance sampling of water fr om SLCWS Well #18. 8 pages.

46. EPA START ( UOS ). 2012. Memorandum of t elephone conversation held on April 5, 2012 between F lorence Reynolds, Water Quality and Treatment Administrator, Salt Lake City Department of Public Utilities (SLCDPU) (801)483

- 6864, Laura Brief er , Special Projects Manager, SLCDPU (801) 483 - 6741 , Jesse Stewart, Project Manager, MWH Americas (801) 617

- 3200
, and Jeff Miller, EPA START ; regarding municipal water sources in Salt Lake City, the SLCWS policy of not utilizing water from contamina ted sources, and the timing of SLCWS Well #18 being taken offline due to tetrachloroethylene (PCE) contamination

. Dated April 5

, 2012. 1 page.

47. EPA. 1998. Multi

- Media, Multi

- Concentration, Organic Analytical Service for Superfund. Publication 9240.0

- 08FSB. January 1998. 4 pages.

48. Agency for Toxic Substances and Disease Registry (ATSDR). 1997. Toxicological Profile for Tetrachloroethylene

. September 1997. Excerpt. 6 page s. A complete copy is available at: http://www.atsdr.cdc.gov/toxprofiles/tp18.pdf

49. EPA. 2010. Utah: Salt Lake City – Salt Lake City Works with Stakeholders to Protect its Water Supply. EPA Office of Water (4606M). Dated January 2010. 4 pages. Source: http://water.epa.gov/infrastructure/drinkingwater/sourcewater/protection/casestudies/upload/Source Water

- Case

- Study

- UT

- Salt

- Lake

- City.pd f

50. SLCDPU

. 2009. SLCDPU 2009 Water Conservation Master Plan. Excerpt. 4 pages. A complete copy is available at: http://www.slcclassic.com/utilities/PDF%20Files/2009%20Water%20Conservation%20Master%2 0Plan%20

- %2011

- 03

- 2009.pdf

51. EPA START ( UOS ) . 2012. Ground W ater T argets figure. Data compiled from UDEQ Division of Drinking Water and Utah Division of Water Rights records available at: http://mapserv.utah.gov/Deq/ and http://www.waterrights.utah.gov/wrinfo/query.asp

52. UDWR. 2012. Records of water system facilities (wells, sprin gs, and surface water intakes) for the Salt Lake City Water System and the South Salt Lake City Water System. C ompiled from UDEQ Division of Drinking Water records available at: http://mapserv.utah.gov/Deq/

. All annotations within reference obtained within source database or at http://www.waterrights.utah.gov/wrinfo/query.asp

. 85 pages.

53. South Salt Lake City. 2011. City of South Salt Lake, State of Utah, Comprehensive Annual Financial Report for Fiscal Year Ended June 30, 2011. A complete copy is available at: http://www.southsaltlakecity.com/uploads/documents/City_of_South_Salt_Lake_2011_CAFR[1].pd f ; C ity of South Salt Lake Public Works, 2011 Annual Report. Excerpt. 2 pages. A complete copy is available at: http://www.southsaltlakecity.com/uploads/documents/Inser t- Water_Quality_Report.pdf Total of 4 pages.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 12 54. U.S. Bureau of the Census. 201 2. Salt L ake City and County QuickFacts. Persons per household, 2006

- 2010 and percent population change . 2 pages. Source s: http://quickfacts.census.gov/qfd/states/49/49035.html and http://quickfacts.census.gov/qfd/states/49/4967000.html

55. SLCDPU. Undated. Salt Lake City Watershed Management Prog rams: 1847 – 1997. By LeRoy W. Hooton, Jr. Excerpt. 2 pages. A complete copy is available at: http://www.slcclassic.com/utilities/PDF%20Files/watersh.pdf

56. UDEQ. 2012. Rule R309

- 600 Drinking Water Source Protection for Gr ound Water Sources. Excerpt. 4 pages. A complete copy is available at: http://www.drinkingwater.utah.gov/documents/rul es_ddw_version/R309

- 600_10

- 29

- 03.pdf

57. UDEQ. 2012. Maps showing Ground Water Protection Zones for wells within a 1 mile radius of the

source (8 th South Well and Well #18). 2 maps. Information added to maps obtained from References 20

- 22, 26

- 28, 45 and sourc e database

. Location : http://mapserv.utah.gov/DEQ

58. EPA. 1999. USEPA Contract Laboratory Program, National Functional Guidelines for Organic Data Review. OSWER 9240.1

- 05A

- P. PB99

- 963506. EPA540/R

- 99/008. October 19 99. Excerpt. 1 page. A complete copy is available at: http://www.epa.gov/superfund/programs/clp/download/fgorg.pdf

59. EPA. 2008. USEPA Contract Laboratory Program, National Functional Guidelines for Superfund Organic Methods Data Review. OSWER 9240.1

- 48. USEPA

- 540 -R- 08

- 01. June 2008. Excerpt. 1
page. A complete copy is available at: http://www.epa.gov/superfu nd/programs/clp/download/somnfg.pdf

60. EPA. 2000. Exfiltration in Sewer Systems

. EPA/600/R

- 01/034. December 2000. Excerpt. 7 pages. A complete copy is available at: http://nepis.epa.gov/Adobe/PDF/200 0E6PB.pdf

61. UDEQ. 2002. Site Inspection Analytical Results Report, University of Utah Building 515, Salt Lake County, Utah. UT0001908821. Dated July 24, 2002. Excerpt. 39 pages.

62. Jordan Valley Water Conservancy District (JVWCD)

. 2012. Source Protection. Webp age describing where JVWCD water sources and delivery. Source: http://www.southsaltlakecity.com/department

listings/public

- works/water A ccessed August 2, 2012.

63. EPA START (UOS). 2012. Telephone conversation with Ed Rufner, Deputy Director, South Salt Lake City Department of Public Works (801) 412

- 3210, regarding the source, blending and distribution of water within the South Salt Lake City Water System. August 14 , 2012. 1 page.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 13 S ITE DESCRIPTION

The 700 South 1600 East PCE Plume site (‘the site’) includes one source and an area of ground water that has been contaminated by tetrachloroethylene (PCE). The scored source is an historic disposal of PCE

contaminated condensate water (aka separator water) from a former dry cleaning facility located within Building 7 of the George E. Wahlen Department of Veterans Affairs Medical C enter Campus (the ‘VA Medical Center’) (Figures 1, 2 of this HRS documentation record ). PCE

- contaminated condensate from the dry cleaning operation was disposed into a drain line attached to a sanitary sewer line ( Figures 1, 2; Ref s

. 8, pp. 2, 3 ; 10, pp. 11

- 13; 11, pp. 2 -7)

. The EPA identification number for the site, as recorded in the Compr ehensive Environmental Response, Compensation and Liability Information System (CERCLIS) database, is UTD981548985 (Ref. 6). The related East Side Springs site is a ‘child’ site under CERCLIS and has been given the EPA identification number UTN000802825 (Ref. 7). Site

- related contamination is also described in East Side Springs documents.

The Maximum Contaminant Level (MCL) for PCE in drinking water set by the United States Environmental Protection Agency (EPA) is 5 micrograms per liter ( μ g/L) (equivalent to 5 parts per billion (ppb)) (Ref. 2, p. 2). Water from a number of wells and springs in the area has PCE levels above the MCL and a Salt Lake City municipal well has been shut down permanently due to the contamination ( Figure 1, Refs

. 20, p. 13, 25, 27
, 67, 69, 79; 21, pp. 6, 11, 15; 22, pp. 18, 45, 47; 23, pp. 6, 38, 40, 42, 48; 24, pp. 5

- 33; 25, pp. 2

- 5; 26, p. 17, 19; 27, pp. 2

- 4, 7, 10, 13, 21, 24, 29, 32, 35, 38, 41, 44 ; 28, pp. 6, 8, 9, 14, 16, 18, 19, 27, 28, 29, 33, 35

- 37, 58, 73, 83, 85, 103, 14 3 ; 29, pp. 18

- 22 )

. Ground water collected from a location immediately upgradient of Building 7 is not contaminated with PCE (Refs. 20, pp. 25, 27, 79; 23, pp. 6, 50; 24, pp. 6, 24; 26, pp. 2, 17; 28, pp. 15, 27, 29, 33, 35, 36, 81)

.

The contaminated ground water extends from an area immediately hydraulically downgradient from the VA Medical Center Building 7 to a number of springs (the ‘East Side Springs’ ) located approximately 1 mile down gradient ( Figure 1, Refs

. 20, p. 13, 25, 27 , 67, 69, 79; 21, pp. 6, 11, 15; 22, pp. 18, 45, 47; 23, pp. 6, 38, 40, 42, 48; 24, pp. 5- 33 ; 25, pp. 2

- 5; 26, p. 17, 19; 27, pp. 2- 4, 7, 10, 13, 18, 21, 24, 29, 32, 35, 38, 41, 44 ; 28, pp. 6, 8, 9, 14, 16, 18, 19, 27, 28, 29, 33, 35

- 37, 58, 73, 79, 83, 85, 103, 105, 142 ; 29 , pp. 18

- 22 ). While the full extent of the contamination has not yet been determined , the center of the known extent is approximately latitude 40 .75 3938 **°** North and longitude 111 .848022 **°** West ( Figure 1)

. The elevation is approximately 4,640 feet above mea n sea level (amsl) at this location (Figure 1).

While ground water collected from various wells immediately downgradient of Building 7 is contaminated with PCE, ground water collected from a well (EPA

- MW

- 05) located immediately upgradient of Building 7 i s not (Refs. 20, pp. 25, 27, 79; 23, pp. 6, 50; 24, pp. 6, 24; 26, pp. 2, 17; 28, pp. 15, 27, 29, 33, 35, 36, 81)

. The surrounding land use includes the University of Utah (U of U) Campus to the north and east, U of U housing to the southeast, the Mount Olivet Cemetery

, the Salt Lake City Sports Complex/Sunnyside Park to the west and southwest and residential areas farther to the south and west ( Figure 3)

. The contaminated ground water underlies numerous residences downgradient of the source , as well as the East High School (Figure 1 of this HRS documentation record , Ref. 28, pp. 14, 19 ).

Construction of the VA Medical Center (then called the Fort Douglas Hospital) was completed in 1952 (Ref. 8, p. 14)

. Since its construction, the u se of Building 7 (den oted as ‘B.07’ in many VA Medical Center records) ha s been multipurpose and, in addition to laundry facilities (Ref. 8, p p . 20 , 21, 25, 28, 29, 30, 32, 34 ) , has previously been used for warehousing (Ref. 8, pp. 21, 29) , animal surgery and research (Ref. 8, pp. 21, 29)

, and a garage (Ref . 8, pp

. 27 , 28 ). A single dry cleaning machine was used at the VA Medical Center from approximately 1976 through 1984 and was located at the same area of Building 7 where the current ‘wet’HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 14 laundry is located (Ref. 8, pp. 2, 3). Architectural drawings supplied by the VA show that a single dry cleaning machine was installed inside what was then the northern exterior wall of Building 7, approximately in the middle of the building when measured from the southeast to the northwes t (Ref . 8, p. 44, 47 ). Additions have since been added to this side of Building 7 ( Figure 2 ). A 1⁄2

- inch diameter condensate drain line from the machine was tied into a new 2 inch drain line leading from the machine (Ref. 8, p 45 - 47). The new 2 inch drai n li ne was tied into an existing 10

- inch drain line located within an adjacent utility tunnel (Ref. 8, pp. 42

- 47). This 10

- inch drain line is the sanitary sewer line that leads from Building 7 (Ref. 8, center of page 36, just right of center on page 40), travels towards the southeast, and then runs generally southwest towards Sunnyside Avenue ( Figures 1, 2, 3 of this HRS documentation record ; Ref. 8, pp. 34 - 40). The dry cleaning machine was removed at some point during or prior to 1984 (Ref. 8, p. 2).

T he PCE

- contaminated ground water was discovered in 1990 during routine sampling of the Mount Olivet Cemetery irrigation well (Ref. 9) , which is located about 2,200 feet down hydraulic gradient from Building 7 ( Figure 3 ) . Since that time, t he site has been through several name changes, including ‘Utah Army National Guard Site’, ‘Mount Olivet Cemetery Plume’, ‘Mount Olivet Ground Water Plume’, and ‘700 South 1600 East PCE Plume’, as efforts to define the extent of the contamination , and to pinpoint the sourc e have progressed

. The full extent of contaminated ground water is unknown

, but with the recent (2010/2011) discovery of the downgradient PCE

- contaminated springs (the ‘East Side Springs’)

, contamination is now known to cover over 2 00 acres (Figure s 1 , 3 of this HRS documentation record )

. The vertical extent of contamination is unknown, but based on discrete interval sampling conducted in 2011 within the Salt Lake City Water System (SLC WS ) W ell #18 (also known as the 500 South Well (Figure 3) ), reache s to at least 274 feet below the ground surface (bgs) at that location (Ref. 29, p. 22)

. This well was taken offline permanently due to this PCE contamination in October 2004 (Refs. 46; 52, p. 26).

O ne source has been identified at the site for HRS scori ng purposes

. The source is the historic disposal of PCE from the dry cleaner into a drain line attached to the sanitary sewer line that leads from Building 7 (Ref. 8, p. 2). It has been documented that PCE was the solvent used at the VA dry cleaning faci lity (Ref. 8, pp. 2, 3)

. While an exact hazardous waste quantity of PCE disposed into the drain line cannot be determined, it is known that condensate water (aka separator water) contains PCE, typically being saturated with respect to the solvent (Ref. 10 , pp. 11, 12; Ref. 11, pp. 2

- 7) . At room temperature, approximately 150 milligrams per liter (mg/L) of PCE would have been d issolved in the separator water (Ref. 10, p. 12; Ref. 11, p.4, 5 ). One study showed that the average concentration of PCE in conde nsate waters from nine dry cleaners in California was 151,800 ppb (Ref. 32, p. 12). This level is 30,000 times the MCL (Ref. 2, p. 2 ). The discharge from most dry cleaning units contains primarily water with dissolved PCE, but also contains some pure cle aning solvent and solids containing PCE (Ref. 32, p. 4).

One study has shown that the most frequent type of PCE release from dry cleaners is a release from sewer lines (Ref. 33, p. 4). Being heavier than water, PCE settles to the bottom of a sewer line and exfiltrates through it, leaking through breaks or cracks, as well as pipe joints and other connections (Ref. 32, pp . 4 , 6, 21 ). Exfiltration rates from clay sewer pipes in various areas of the U.S. have been estimated to be between approximately 5,000 and 77,000 gallons per inch diameter of pipe, per mile length, per day (Ref. 60, pp. 4

- 6). In addition to leaking through joints and cracks , PCE has been reported to penetrate through sewer lines by other methods, including by leaching directly through the line, by volatilizing from the outer edge of the pipe into the surrounding soils, and by penetrating the pipe in gas form (Ref. 32, pp. 21

- 23). Due to having a greater vapor density than air, once in soil, PCE vapors sink down through the vadose zone to the ground water (Ref. 32, p p. 4 , 6, 22 ).

Employees of the Salt Lake City Department of Public Utilities ( SLCDPU ) documented observations of discolored water and odors of dry cleaner solvent at various dates in the early 1980’s while cleaning theHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 15 sanit ary sewer line (Ref. 14). A video survey of sections of the sewer line s between Building 7 and Sunnyside Avenue was conducted on December 17, 2003 by the SLCDPU (Ref. 15)

. This survey documented numerous defects in most of the sections , including cracks , root penetrations

, of fsets , and a pipe sag, as well as evidence of historic breaks, repairs and replac e ments of the clay pipe (Ref. 15). At least one of these pipe repairs document s that the clay pipe had been broken sometime prior to the sewer survey ( Ref. 15, p. 11 ).

Soil gas above the sanitary sewer line was sampled for PCE in 1996 and again in 2006 (Refs. 12, 13). Despite the tests being conducted at least 12 and 22 years, respectively, after the dry cleaner was removed from service, and that PCE vapors tend to sink rather than rise through soil (Ref. 32, p. 6), PCE was detected in soil gas at some locations above the sanitary sewer line . The highest concentrations detected at locations closest to Building 7 (Ref s . 12, pp. 6, 7, 13

- 16 ; 13, pp. 4, 6, 7, 9, 14).

Ground water downgradient of Building 7 and the sanitary sewer line contains PCE at concentrations greater than background levels, indicating that a release of hazardous substances has occurred to the ground water as documented in Section 3 .0 of this HRS documentation record. In 2004, thirteen municipal drinking water wells located within a 4

- mile radius of the source provided water to the loca l population (Ref. 51; 52, pp. 4, 5, 8) . One of these wells, SLC WS Well #18, w as shut down in 200 4 due to PCE contamination and is evaluated

as an actual contamination target (Ref. 46 ). Four of the remaining wells are evaluated as potential contamination targets (see Section 3.3 of this HRS documentation record).

OPERATIONAL AND REGULATORY HISTORY

The dry cleaner was operational from approximately 1976 through 1984 (Ref . 8, pp. 2, 3, 20, 21, 24, 26 ). Only one dry cleaning machine was installed and operated, and the estimated quantity of dry cleaning processed monthly was 700 items (Ref. 8, p. 2). Items that were dry cleaned were drapes and uniforms (Ref. 8, p. 2). PCE was used in the dry cleaning process (Ref. 8, p. 2).

T he dry cleaning system was a ‘ closed loop ’ system (Ref. 8, p. 2 , 3; Ref. 10, p. 7) , meaning the system contained a distillati on process for the recovery of PCE at the end of each cycle (Ref. 8, p. 2, 3). The VA reported that there was no documentation to support that they ever had below or above ground tanks used for storing spent solvents, chlorinated solvents, waste fluids or materials containing spent chlorinated solvent (Ref. 8, p. 3). The condensate from the distillation process was emptied directly into a drain line attached to the sanitary sewer (Ref. 8, p. 2 , 3 ). The disposal of dry cleaner separator water to a sanitary sewer or septic tank was common practice in the 1980’s (Ref s . 10, p. 15; 32, pp. 11, 12 ).

According to the VA, the distillation process was efficient enough that very little PCE was added to the system on a weekly basis for recharge (Ref. 8, p.2 , 3 ). PCE was purchased and stored in 55

- gallon containers. The rate at which the 55

- gallon containers were used is unknown (Ref. 8, p. 2 , 3 ), but PCE consumption per weight of material cleaned has been reported to vary from 420 pounds of material per gallon to less than 100 pounds of material per gallon, depending upon the overall performance of the dry cleaning equipment and the effectiveness of operating procedures (Ref. 16, p. 5). Prior to 1992, a typical dry cleaner business used between 15 and 40 gallons a month of pure PCE (Ref. 32, p. 5).

No historical records of inspections or historical reports of violations by the operators of the dry cleaning operation by any regulatory agency have been located

.

PREVIOUS INVESTIGATIONS

The PCE contaminat ion was first discovered at the 700 South 1600 East site in 1990 when analytical results from an irrigation well (the Mount Olivet Cemetery irrigation well) located down

- hydraulic gradient of the VAHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 16 Medical Center indicated a concentratio n of PCE of 32 μg/L ( Figur e 3 of this HRS documentation record ; Ref. 9 ). Since that time, numerous investigations have been conducted in the area in an effort to characterize the extent, nature and origin of the contamination

.

Under the Safe Drinking Water Act, enacted in 1974 and amended in 1996, the SLCWS is responsible for the sampling and analysis (monitoring) of its water supplies in order to ensure that drinking water quality meets minimum standards (MCLs) established under the law. Analytical results from this compliance sampling show that the SLCWS Well #18 (Figure 3 of this HRS documentation record ) was free of PCE contamination until 1997, when the first detection was recorded (Ref. 45, pp. 1

- 5). PCE was detected in the well periodically after this time, with concentrations dependent upon the duration of pumping of the well (i.e. PCE was generally not detected when the well had not been in use for a period of time . Pumping draws the contamination into the well, resulting in increasing concentrations of PCE with continued use. When pumping ceases, the contamination recovers it s ambient flow direction away from the well, resulting in lower PCE concentrations,

or non

- detections.) (Refs. 25, pp. 1

- 7; 29, pp. 20

- 22 , 28, 33 ). 1989 through 2004 – SLC WS, ground water from SLCWS We ll #18 (Ref. 45)

During May and June of 1995 , Ecology and Environment, Inc. (E&E) on behalf of the EPA’s Superfund Technical Assessment and Response Team (START) program, c ollected soil and soil

- gas samples fro m various locations in the vicinity of the Mt. Olivet well in an effort to locate the source and extent of the PCE detected in the well ( Ref s. 18 , 19 ) . During the first field sampling effort in May , PCE was detected in one of 15 soil gas samples at a conc entration of 16 ppb ( sample ID: OG

- SG

- 06) (Ref. 18, pp. 5

- 9). E PA START returned the following month with a hydraulic

- push machine to collect ground water samples in the vicinity of the maintenance shop and the VA M edical C enter. A hard calcareous calic he layer caused refusal at no more than 12 feet bg s; consequently, only soil gas samples were collected (Ref. 19, p. 5). For example; soil gas samples collected on the VA Medical Center property could only be taken from 3 feet bgs (Ref. 19, p. 14). N o det ections of PCE were recorded in any of 4 soil and 5 soil gas samples above the laboratory reporting limit of 10 ppb (Ref. 19, pp. 4- 6, 9

- 14). The reports completed in regards to this work identified the most likely source of contamination for the Mt. Oli vet well as appearing to be the Utah National Guard maintenance shops located east

- southeast of the well (Refs. 18, p. 4; 19, p. 4), but stated that a potential source for the PCE contamination of the well was not located (Ref. 19, p. 6). 1995 – EPA START
, s oil gas (Refs. 18, 19)

Additional soil gas samples were collected by EPA START in October and November, 1996 (Ref. 13 ). Soil gas samples were collected from three different areas on October 18, 1996: three samples were collected from east and southeast of Building 7 where the sewer line exited the building, two samples were collected on the Fort Douglas Military Reservation (approximately 3,600 feet northeast of Building 7), near Red Butte Creek, and one sample was collected near Building 515 of the Fort Douglas Military Reservation (approximately one mile northeast of Building 7) (Ref. 13 pp . 2, 3, 6 ). The same locations were targeted again on November 9, 1996, although two of the locations near Building 7 could not be resampled due to construction activit ies (Ref. 13, p. 3). The results from the other four resampled locations are included in the report and show detections of PCE within the one sample collected adjacent to the sewer line near Building 7 (1.9 μg/L ), as well as detections of PCE (49 μ g/L ) fr om the sample collected near Building 515 (Ref. 13, pp. 2

- 4, 6, 7, 9, 11, 14). 1996 – EPA START
, s oil gas (Ref. 13)

From June through August 1998, EPA START installed six (one dual

- nested an d four individual) ground
water monitoring wells at five locations east and southeast of the cemetery to provide information regarding ground water flow direction, gradient, the extent of PCE contamination, and attribution, if possible (Ref. 20,
pp . 10, 23 )

. 1998 – EPA START
, g round water (Ref. 20)HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 17 The wells were screened in the first aquifer encounte red and depth to ground water in November 1998 varied from approximately 130 to 205 feet bgs (4483.55 feet to 4527.38 feet amsl ) (Ref. 20, p p. 29 , 40

- 51 ; Table s 5 and 9 of this documentation record )

. The ground water flow direction was reported to be towa rds the northwest (Ref. 20, pp. 17, 23), although a recent study utilizing a larger number of wells and ground water flow modeling has shown that ground water actually flows to the west

- southwest ( Ref. 29, pp. 11, 31 ).

A formal sampling event was conduct ed in November 1998 (Ref. 20, pp. 13 - 16)

. Concentrations of PCE in the wells ranged from non

- detect (at the Contract Required Quantitation Limit (CRQL) of 10 μg/L ) in the background well EPA

- MW

- 05, to 320 D μg/L in the well EPA

- MW

- 01S (Ref. 20 , p. 13
, 25
, 27 , 67, 69, 79).

PCE contamination was present up

- hydraulic gradient of the Utah National Guard maintenance shops, previously considered to be the likely source. The report identified the former VA Medical Center dry cleaning operation as a potential source, and stated that Building 7 could be a source if PCE travelled south or southeast from Building 7 along a sewer line or other conduit prior to infiltration to the aquifer (Ref. 20, p. 18, 19).

One of the well s installed by EPA START in 1998 (EPA

- MW

- 03 ) was abandoned in September 1999 due to the construction of what is now the Salt Lake City Sports Complex (Ref. 21, p

. 6). A final sampling of this well on September 20, 1999 prior to abandonment conf irmed the presence of PCE at a concentration of 7.1 μg/L (Ref. 21, pp. 6, 11, 15). The laboratory data package for this sample is unavailable. 1999/2000 – EPA START , ground water (Ref. 21)

Also during this time, an additional well (EPA

- MW

- 06) was installed in the southeast corner of Sunnyside P ark

, in a location thought to be upgradient of both the PCE contaminated wells installed in 1998, as well as
t he sewer line that originates from the former VA dry cleaning facility (Ref. 21, p p . 6, 13 ). The well was screened in the first aquifer encountered and depth to ground water in October 1999 was estimated to be 118.21 feet bgs (45 61.79 feet amsl) (Ref. 2 1 , p. 16 ). The screened interval for EPA

- MW

- 06 is approximately (4,580 to 4,550) (Ref. 21, pp. 16, 21, 22).

EPA

- MW

- 06 was sampled on January 6, 2000 returning a non

- detect result for PCE at the CRQL of 10 μg/L (Ref. 21, pp. 7, 9, 10, 15, 18

- 22, 30, 34, 43).

It was stated in the report that while the specific location of the PCE release was still not defined, the only identified potential source of P CE that was both downgradient of the background wells and upgradient of the contamin ation wa s the former VA dry cleaning facility (Ref. 21, p. 10).

In August 2000, the UDEQ produced a summary report on the work don e at the site to date (Ref. 22). In addition to t he EPA START soil gas and ground water studies from 1996 through 2000 (included as appendices in the report) (Refs. 13, 20, 21), the report also presented analytical data from the sampling of springs (scree ning level data only) conducted by the UDEQ in August and September of 1999, and sampling of two water supply wells ( SLC WS Well # 18 - called the 1511 East 500 South Sa lt Lake City well in the report - and the Mount Olivet Cemetery well ) was conducted in September 1998 (Ref. 22, p p . 11, 12 , 17, 18 ). The spring samples were collected in an attempt to track the contamination ’s western and southwestern extent, under the assumption that ground water flow was to the west to southwest (Ref. 22, p. 11) . T he Mt

. Olivet well sample was collected in order to verify the presence or absence o f contamination

, and the SLC WS Well #18 (500 South well) was sampled to help determine the northern extent of the contamination (Ref. 22, p. 12, 18). 1999/2000 – UDEQ, ground water (Ref. 22)

Analytical results from the springs showed non

- detects for PCE at the CRQL of 10 μg/L (Ref. 22, p p. 28
, 30 )

. This data was collected for screening purposes only and no primary reference for the data set is available.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 18 Analytical results from the supply well samples show a PCE con centration of 150 μg/L in the Mt. Olivet well (sample ID s: MT

- 01 , HS794 ) and a non

- detect value for SLC WS Well #18 (500 South Well, sample ID s : MT

02 , HS795 ) at the CRQL of 10 μg/L (Ref. 22, pp. 18 , 45, 47).

The report identified that the Utah Army Nati onal Guard Maintenance Shop 5 was no longer thought to be the source (Ref. 22, p. 7, 9) and stated that “... the source for contamination of the aquifer is southeast of monitoring wells EPA

- MW

- 01S and EPA

- MW

- 02, west of EPA

- MW

- 05, and northwest of EPA

- MW

- 06. The only identified potential source of PCE in this area is the sewer line that originates from the former dry cleaning facility at the VA Medical Center .” (Ref. 22, p. 23 ).

A video survey of sections of the sewer lines between Building 7 and Sunnyside Avenue was conducted on December 17, 2003 by the SLCDPU at the request of the UDEQ and the EPA (Ref. 15 , p. 15 ). The survey

was performed to see if there were any major breaks or cracks in the sewer line th at could ha ve provided for a historical preferential pathway for contaminants to get into the soil or ground water (Ref. 15, p. 15). This survey documented numerous defects in most of the sections, including cracks, root penetrations, offsets, and a pipe sag, as well as evidence of historic breaks, repairs and replacement s of the clay pipe (Ref. 15). 2003 – UDEQ, EPA, SLCDPU, sewer survey (Ref. 15)

The UDEQ conducted soil sampling along the sewer line leading from Building 7 in June 2004, and conducted
a gr ound water sampling event in October 2004 (Ref. 23). The objective of the soil sampling was to determine whether a PCE source existed along the sewer line by collecting soil samples at roughly 50 foot intervals along the length of the sewer line, starting at Building 7 and continuing south southwest to Sunnyside Avenue ( Ref. 23, p. 3-6 ). 2004 – UDEQ, soil and ground water (Ref. 23)

A total of thirty

- two soil samples were collected with a hydraulic

- push machine, with sample depths ranging from 2 feet to 13 feet bgs. Samples were collected both upgr adient and downgradient of the sewer line (Ref. 23, p. 4). All sample results indicated that no volatile organic substances ( VOCs ) were detected above the reporting limit s of 10 to 12 μg/kg (Ref. 23, p. 4-6 , 11

- 30 ). The possible reasons for the lack of d etections were not given in the report, although it may be due to a number of factors , including: the length of time that had passed since disposal from the dry cleaner had occurred (at least 20 years); inability to sample deep enough due to the hard cal iche layer reported from earlier investigations; because PCE in its liquid state is heavier and less viscous than water and would be expected to sink directly below the pipe (not be found above); and that PCE vapors are denser than air, and would also would have been expected to sink below the pipe (Ref. 32, pp

. 5, 6). Specific sample depths were not cited in the report.

A total of four ground water monitoring wells (three downgradient and one upgradient of the dry cleaner) were sampled on October 15, 2 004 as part of this investigation (Ref. 23, pp. 4, 31

- 73). PCE was detected in all three of the downgradient wells with PCE concentrations ranging from 2.23 μg/L in SLC WS Well #18 to 128 μg/L in the Mt Olivet Well (Ref. 23, pp. 6, 38, 40, 42, 48). The ba ckground well EPA

- MW

- 05 was non

- detect at a reporting limit of 1 μg/L (Ref. 23, p. 50).

The USGS was engaged by the EPA to perform a ground water study in 2004 and early 2005 (Ref. 24). USGS activities included the collection of water level measurements from monitoring and supply wells, and the collection of ground water samples from nine wells, including the two U of U wells and the SLC WS Well #18 (named SLC 1016a in the documents) (Ref. 24, pp

. 1-6 ). The overa ll objective of the study is not clear from available documents. 2004/2005 - USGS, ground water (Ref. 24)HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 19 Analytical results from the sampling performed in February 2005 show detections of PCE in all wells sampled with the exception of the background well EPA

- MW

- 05 and the two U of U wells , wh ich were all non

- detect for PCE at a reporting limit of 0.1 μg/L (Ref. 24, pp. 5- 33 ) . PCE detections ranged from 0.2 μg/L in EPA

MW

- 01D to 296 μg/L in EPA

- MW

- 02 (Ref. 24, pp

. 5, 13, 30 ).

In September 2005, UDEQ collect ed a time series of water samples from SLC WS Well #18 in order to determine the current level of contamination in the well and whether continuous pumping affected PCE concentrations (Ref. 25). PCE concentrations from the well water increased from 1.2 μg/L on September 12 to 1.8 μg/L on September 29 (Ref. 25, pp. 2- 5). 2005 - UDEQ, ground water (Ref. 25)

In October 2005, EPA START collected water samples from four of the ground water monitoring wells established in the vicinity of the VA Medical Cente r in order to determine current contaminant concentrations (Ref. 26). PCE concentrations from the wells ranged from non

- detect in background well EPA

- MW

- 05 (Sample ID MW

- 05) ( at a CRDL of 0.5 μg/L ) (Ref. 26, p p . 2, 16, 17) to 160 μg/L in downgradient well EPA

MW

- 02 (Sample ID MW

- 02) (Ref. 26, p p

. 3, 18, 19). 2005 – EPA START , ground water (Ref. 26)

In February 2007, IHI Environmental, under contract to the VA Medical Center , installed 48 passive soil gas samplers along the sanitary sewer line between Sunnyside Avenue and Building 7 (Ref. 12, p. 4). Two additional samplers were installed at background locations (Ref. 12, p. 4). All samplers were deployed from 0

- 12” bgs and were retrieved after approximately 10 days exposure to the soil (Ref. 12, p p . 5, 20 ). 2007 – IHI Environmental, soil gas (Ref. 12)

Analytical results showed detections of PCE above the method detection limit (of 25 nanograms [ng] ) in 6 samples collected from 4 locations , with a maximum concentration of 90 ng (Ref. 12, p. 7, 11, 12, 13

- 16). Three of these locations were adja cent to Building 7, while the fo u rth location was along the sewer line approximately 1,000 feet southeast of Building 7 (Ref. 12, pp. 11, 12, 13

- 16). After receiving preliminary results, duplicate analysis was performed on two impacted samples (Ref. 12, p . 8). Analytical results from both background samples were non

- detect at the method detection limit of 25 ng (Refs. 12, pp. 11, 12, 13

- 16).

It is asserted in the report that “While PCE was present in the soil gas, it was present at concentrations far belo w those expected in a release” (Ref. 12, p. 10). However, a lthough it is stated in the report that 'Weather conditions during the soil gas investigation would not have influenced the outcome of the investigation’ (Ref. 12, p. 5) this assertion is not explained further. A s the sampling was conducted in the middle of winter (February) , any PCE in the shallow ground would be expected to be less likely to be volatized than if the investigation had been conducted in the higher temperatures of summer. In addit ion, it is reported that sample installation procedures were standardized to those followed for installation of samplers in asphalted locations (i.e. samplers were placed within a 1

- foot section of copper tube), even for locations w h ere no asphalt was
pres ent (Ref. 12, p. 5). This procedure may impart a low bias in the analytical results as the samplers would be not be exposed to soil gas from the full length of the soil column, but only to that gas able to penetrate the end of the tube. Finally, it is ind icated that sampling locations were biased in order to detect “worst case ” conditions directly above the sewer line, even though PCE vapor is heavier than air and hig h est concentrations would be expected beneath or to the sides of the pipe (Ref. 32, p. 6). It may be that concentrations of PCE in the soil gas were low simply due to the length of time that had passed since PCE disposal to the sewer line had occurred (i.e. at least 23 years).

On June 12, 2010, a release of cr ude oil from a Ch evron pipeline was discovered at the base of Red Butte Cany on east of the site (Ref . 27, p

. 1)

. As part of the overall response effort, the SLCDPU began identifying 2010 – SLC DPU , springs (Ref. 27)HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 20 potential downgradient receptors for the crude oil contamination. SLCDPU identified 25 springs along the Wasatch Fault line in the area between 800 South and Michigan Avenue and between 1100 East and 1300 East as potential receptors for the contamination (Figure 3; Ref. 28, pp. 8, 9) . Due to access issues and other factors, samples were collected from only eleven of the springs, as well as one storm drain manhole, and two artesian wells available for use by the public . Sampling events were conducted from June through August 2010 (Ref s . 27, p p

. 14, 25, 45, 46; 28, pp. 8, 9 ).

Analytical resu lts from the sampling showed that PCE was present in 6 of the 11 springs sampled, as well as from the storm drain (Ref. 27, pp. 3, 4, 7, 10, 13, 18, 21, 24, 29, 32, 35, 38, 41, 44 ). Concentrations of PCE in the springs ranged between 2.5 μg /L and 40.4 μg/L

. Given the springs ’ location s downgradient of the known PCE contamination within the Mt. Olivet well, the existing PCE contamination ( i.e

. the site ) was considered the likely source of the PCE ( Ref. 28, pp. 6, 19 ). The area of contaminat ed springs was listed in the CERCLIS database as the “East Side Springs ” site in January of 2011 (Ref. 28, p. 9 )

Following the discovery of the contaminated springs in 201 0 , the UDEQ conducted a follow

- on investigation in November and December 2011. The investigation involved the collect ion of surface water, surface soils, and ground water from the wider area (including the site), including water and soils from three springs, water from three exi sting ground water monit or ing wells and five new ly

- placed direct

- push borings, and water from the fountain at Liberty Park and the 8 th South artesian well (aka 8 th South Well) (Ref s

. 28 , pp. 9 , 13 ; 52, pp. 68, 69 ). 2011 – UDEQ, springs, surface soils, ground water (Ref . 28)

A nalytical results from the samples conf irm the presence of PCE contaminati on in ground water adjacent to the springs, as well as fro m the existing monitoring wells (Ref. 28, pp. 6, 14, 16, 17, 19, 27

- 29, 33, 35

- 37, 73, 79, 83, 85, 95, 103, 105 ). Concentrations of PCE in the springs ranged from a non

- detect in one spring (at the CRQL of 5 μg/L ), to 20 μg/L (Ref . 28, p p. 16, 28, 33, 37, 101, 103, 105 ). Co ncentrations of PCE in the existing wells and the direct

- push borings ranged from a non

- detect (at CRQL of 5 μg/L ) in the background well EPA

- MW

- 05 to 150 μg/L in well EPA

- MW

- 01S (Ref . 28, pp. 14, 15, 27, 33, 35, 36, 73, 79, 81, 83, 85, 95 ). Contamination was not documented in either the soils collected from near the springs, or the two artesian wells located farther downgradient from the springs ( Ref. 28, p p. 13, 15, 27, 34, 35, 75, 77, 120, 121).

From the Fall of 2010 until early 2012, MWH, under contract to the SLCDPU, conducted a variety of acti vities in an effort to assess the short - and long

- term impacts of PCE contamination to SLCWS Well #18, to make recommendations for the future use of the well, and, if deemed appropriate, to design a well

- head treatment system (Ref. 29, p. 9 ). These activi ties included geophysical and hydrophysical evaluation of the well, discrete interval ground water sampling, aquifer testing, and the construction of a ground water model to simulate contaminant transport (Ref. 29, pp. 4, 5, 17

- 22, 27

- 33 ). 2010/2011/2012 – M WH, assessment of SLC WS Well #18, ground water sampling and modeling (Ref. 29)

The study confi rmed that the well is screened from approximately 260 -47 0 feet bgs (4,410 to 4,190 feet amsl ) (Ref s . 29, p p. 24 , 51 ; 40, pp. 1, 9 ). The three most hydraulically

- conductive intervals found in the well were found in its upper portion, from 271 to 368 feet b gs (Ref. 29, 19). During initial interval

- specific sampling efforts, t race

- level concentrations (i.e. less than 0.03 ppb) of PCE were detected from the following depth intervals: 277

- 280, 302

- 305, 346

- 349, 369

- 372 feet bgs (Ref. 29, p. 18) . Later sampli ng performed during a high capacity pump testing showed that PCE contamination increased with pumping duration, showed that contamination is in the upper flow zone (271

- 274 ) and was detectable after less than 10 days of pumping, and recorded a maximum PCE concentration of 0.81 ppb 18 days into the test (Ref. 29, pp. 20

- 22). Information gathered from the aquifer testing, coupled with historic contamination concentration data from established monitoring wells was incorporated into a ground water model for t he site (Ref. 29, pp. 24

- 27). While the identification of a definitive source of contamination was beyond the scope of the investigation, forHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 21 the purposes of the model, a source was assumed to be upgradient of the known contamination and was therefore located near monitoring well EPA

- MW

- 05 at the VA Medical Center (Ref. 29, pp. 25

- 26 , 33, 47. 48 ). The ground water modeling consisted of both particle

- tracking and contaminant transport modeling simulations run over a variety of pumping and source concentratio n scenarios (Ref. 29, pp. 30

- 31). Under steady

- state (no pumping) ambient flow the model predicted ground water flows from the northeast to the southwest (Ref. 29, p. 31). Discrepancies between the model

- predicted ground water gradient and the potenti o me tric surface that has been drawn in previous reports (e.g. Ref. 20, p. 23) is attributed by MWH to be due to perched water and that the ground water flow direction is as modeled (from the northeast to the southwest (Ref. 29, p. 11). The report further sta tes that this flow direction is physically evident given the known distribution of PCE contamination with high concentrations in the vicinity of the well pair at EPA

- MW

01 ( i.e. deep and shallow wells) and the detected contamination in springs along the Wasatch Fault line (i.e. the East Bench Fault) (Ref. 29, p. 31).

Conclusions from the ground water modeling included that , if the well were to be used, PCE contamination would continue to impact the well as its extraction rate (up to 2,300 gallons per min ute [ gpm ] ) would be sufficient to alter the ground water flow regime in the area and would draw contamination into the well (Ref. 29, pp. 33 , 48 ).

2.2 SOURCE CHARACTERIZATION (Ref. 1, p.51588)

2.2.1 SOURCE IDENTIFICATION (Ref. 1, p. 51588)

Source Type : Other ( historic disposal of PCE to sewer )

Description and Location of Source : ( Figures 1 and 2 of this HRS documentation record ):

The source is the historic disposal of PCE

- contaminated condensate (aka separator water) from the distillation
proc ess of the former VA Medical Center dry cleaning operation to the drain attached to the sanitary sewer line that leads from Building 7 (Ref. 8, p. 2).

It has been documented that PCE was the solvent used at the VA dry cleaning facility (Ref. 8, pp. 2, 3)

. The dry cleaning system was a closed loop system (Ref s . 8, p. 2, 3; 10, p. 7). The system contained a distillation process for the recovery of PCE at the end of each cycle (Ref. 8, p. 2, 3). The VA reported that there was no documentation to support t hat they ever had below or above ground tanks used for storing spent solvents, chlorinated solvents, waste fluids or materials containing spent chlorinated solvent (Ref. 8, p. 3). The condensate from the distillation process was emptied directly into a dr ain line attached to the sanitary sewer (Ref. 8, p. 2, 3).

While an exact hazardous waste quantity of PCE disposed into the drain line cannot be determined, it is known that condensate (aka separator water) contains PCE, being saturated with respect to th e solvent (Ref s . 10, pp. 11

- 13 ; 11, pp. 2

- 7). At room temperature, approximately 150 mg/L of PCE would have been dissolved in the separator water (Ref s . 10, p. 12; 11, p.4, 5). In addition to condensate water with dissolved PCE, the discharge would also have contained some pure cleaning solvent and solids containing PCE (Ref. 32, p. 4). Being heavier than water, PCE settles to the bottom of a sewer line and exfiltrates through it, leaking through joints and cracks (Ref. 32, p. 4). Exfiltration rates fro m clay sewer pipes in some areas of the U.S. have been estimated to be between approximately 5,000 and 77,000 gallons per inch diameter of pipe, per mile length, per day (Ref. 60, pp. 4

- 6). PCE, being volatile, also turns into gas and penetrates the sewer wall. PCE then travels through the vadose zone to the ground water (Ref. 32, p. 4).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 22 According to the VA, the distillation process was efficient enough that very little PCE was added to the system on a weekly basis for recharge (Ref. 8, p p. 2, 3). PCE w as purchased and stored in 55

- gallon containers. The rate at which the 55

- gallon containers were used is unknown (Ref. 8, p. 2, 3), but PCE consumption per weight of material cleaned has been reported to vary from 420 pounds of material per gallon to less than 100 pounds of material per gallon, depending upon the overall performance of the dry cleaning equipment and the effectiveness of operating procedures (Ref. 16, p. 5). It has also been reported that, in the early 1990’s a
t ypical dry cleaner business used between 15 and 40 gallons a month of PCE (Ref. 32, p. 5).

The disposal of dry cleaner separator water to a sanitary sewer or septic tank was common practice in the 1980’s (Ref. 10, p. 15). One study has shown that the most frequent type of release from dry cleaners is a release from sewer lines (Ref. 33, p. 4).

PCE has been detected in soil gas above the sanitary sewer line that leads from the former location of the dry cleaner within Building 7, with the highest concentrations detected at locati ons closest to Building 7 (Ref s . 12, pp. 6

- 7, 13

- 16; 13, pp. 4, 6, 7, 9, 14). The presence of PCE in soil gas confirms that the soil has been impacted by PCE.

Employees of the SLCDPU documented observations of discolored water and odors of dry cleaner s olvent at various dates in the early 1980’s while cleaning the sanitary sewer line that leads from Building 7 (Ref. 14). A video survey of sections of the sewer lines between Building 7 and Sunnyside Avenue was conducted on December 17, 2003 by the SLCDPU (Ref. 15). This survey documented numerous defects in most of the sewer line sections, including cracks, root penetrations, offsets, and a pipe sag, as well as evidence of historic breaks, repairs and replacements of the clay pipe (Ref. 15). Waste water , free

- phase solvent, and solvent vapors can leak from sewer lines through crack s , joints or breaks (Refs. 10, p. 16; 32, pp. 3

- 4; 33, pp. 4

- 5). There is no liner situated between the sewer line and the underlying in

- situ soils ( Ref. 31).

Ground water and springs downgradient of Building 7 and the sanitary sewer line contain PCE at concentrations greater than background levels (Refs. 20, p. 13, 25, 27 , 67, 69, 79; 21, pp. 6, 11, 15; 22, pp. 18, 45, 47; 23, pp. 6, 38, 40, 42, 48; 24, pp. 5- 33 ; 25, pp. 2

- 5; 26, p. 17, 19; 27, pp. 2

- 4, 7, 10, 13, 18, 21, 24, 29, 32, 35, 38, 41, 44 ; 28, pp. 6, 8, 9, 14, 16, 18, 19, 27, 28, 29, 33, 35

- 37, 58, 73, 79, 83, 85, 103, 105, 142 ; 29, pp. 18

- 22). This i ndicates that a release of hazardous substances has occurred to the ground water migration pathway as documented in Section 3.0 of this HRS documentation record.

Based on the documented waste disposal practices at the former dry cleaning operation, the condition of the sewer line leading from the operation, the eye

- witn ess account s of dry cleaning solvent being present in the sewer line, the detection of PCE in soil gas above the sewer line in concentrations greater than background levels, and the detection of PCE in ground water and springs downgradient of the sewer lin e in concentrations greater than background levels

, t he source consists of an historic disposal of an unknown quantity (but greater than zero ) of waste water containing PCE.

2.2.2 HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE (Ref. 1, p. 51588)

The dry cleaning facility was operational from approximately 1976 through 1984 (Ref. 8, pp. 2, 3, 20, 21, 24, 26). PCE was used in the dry cleaning process (Ref. 8, pp. 2, 3).

The dry cleaning system was a closed loop system (Ref s . 8, p. 2, 3; 10, p. 7). Th e system contained a distillation process for the recovery of PCE at the end of each cycle (Ref. 8, p p . 2, 3). The condensate from the distillation process was emptied directly into a drain line attached to the sanitary sewer (Ref. 8, p p . 2, 3).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 23 While a n exact hazardous waste quantity of PCE disposed into the drain line cannot be determined, it is known that condensate (aka separator water) contains PCE, being saturated with respect to the solvent (Ref s . 10, pp. 11

- 13; 11, pp. 2

- 7). At room temperature, approximately 150 μg/L of PCE would have been dissolved in the separator water (Ref s . 10, p. 12; 11, p p .4, 5).

Employees of the SLCDPU documented observations of discolored water and odors of dry cleaner solvent at various dates in the early 1980’s whi le cleaning the sanitary sewer line that leads from Building 7 (Ref. 14).

PCE has been detected in soil gas above the sanitary sewer line, with the highest concentrations detected at locations closest to Building 7 (Ref s . 12, pp. 6

- 16; 13, pp. 4, 6, 7, 9, 14). The presence of PCE in soil gas confirms that soil has been impacted by PCE.

Ground water and springs downgradient of Building 7 and the sanitary sewer line contain PCE at concentrations greater than background levels, indicating that a release o f hazardous substances has occurred to the ground water migration pathway as documented in Section 3.0 of this HRS documentation record.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 24 TABLE 1: Evidence Associating PCE with the Source

Hazardous Substance Evidence References

Tet rachloroethylene (PCE) • The VA has stated that PCE was used in the dry cleaning process. PCE

- laden condensate (separator water) was dispos ed to the sewer (i.e. deposition to source).

• A strong dry cleaning solvent odor and discolored water was observed in the sewer durin g the time of dry cleaner operation (i.e. direct observation)

.

• PCE has been identified in soil gas above the sewer, with the highest concentrations occurring at a location closest to the former dry cleaner (i.e. observed release)

.

• PCE ha s been identifie d in ground water immediately downgradient, but not immediately upgradient of the former dry cleaner (i.e. observed release)

. PCE ha s also been identified in springs downgradient of the former dry cleaner

. Ref

. 8, pp. 2, 3 ; Refs. 10, pp. 11

- 13; 11, pp. 2-7

Ref. 14

Refs. 12, pp. 6

- 7, 13

- 16; 13, pp. 4, 6, 7, 9, 14

Refs. 20, p. 13, 25, 27
, 67, 69, 79; 21, pp. 6, 11, 15; 22, pp. 18, 45, 47 ; 23, pp. 6, 38, 40, 42, 48; 24, pp. 5- 33 ; 25, pp. 2

- 5; 26, p. 17, 19; 27, pp. 2

- 4, 7, 10, 13, 18, 21, 24, 29, 32, 35, 38, 41, 44 ; 28, pp. 6, 8, 9, 14, 16, 18, 19, 27, 28, 29, 33, 35

- 37, 58, 73, 79, 83, 85, 103, 105, 142; 29, pp. 18

- 22.

Containment

A study has shown that the most frequent type of release from dry cleaners is a release from sewer lines (Ref. 33, p. 4 ). Being heavier than water, PCE settles to the bottom of a sewer line and exfiltrates through it, leaking through breaks or cracks, as well as pipe joints and other connections (Ref. 32, pp. 4, 6, 21). Exfiltration rates from clay sewer pipes in various areas of the U.S. have been estimated to be between approximately 5,000 and 77,000 gallons per inch diameter of pipe, per mile length, per day (Ref. 60, pp. 4

- 6). In addition to leaking through joints and cracks, PCE has been reported to penetrate throug h sewer lines by other methods, including by leaching directly through the line, by volatilizing from the outer edge of the pipe into the surrounding soils, and by penetrating the pipe in gas form (Ref. 32, pp. 21

- 23).

A video survey of sections of the sewer lines between Building 7 and Sunnyside Avenue was conducted on December 17, 2003 by the SLCDPU (Ref. 15). This survey documented numerous defects in most of the sewer line sections, including cracks, root penetrations, offsets, and a pipe sag, as w ell as evidence of historicHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 25 breaks, repairs and replacements of the clay pipe (Ref. 15). Waste water, free

- phase solvent, and solvent vapors can leak from sewer lines through crack s , joints or breaks (Refs. 10, p. 16; 32, pp. 3

- 4; 33, pp. 4

- 5). There is no liner situated between the sewer line and the underlying in

- situ soils (Ref. 31).

2.2.3 HAZARDOUS SUBSTANCES AVAILABLE TO A PATHWAY (Ref. 1, p. 51588)

The source consists of an historic disposal of an unknown quantity (but greater than zero) of waste water containing PCE. Because the SLCDPU has confirmed that the sewer line leading from Building 7 is not lined and has numerous defects, a containment value of 10, as shown below in Table 2 below, was assigned for the ground water migration pathway (Refs . 1 , Table 3

- 2, p. 51596 ; 22; 31 ).

TABLE 2 : Containment Factor Value for t he S ource

Containment Description Containment Factor Value References

Gas release to air: NS NA

Particulate release to air: NS NA Release to ground water: Because of the direct disposal to the sewer line, and the containment characteristics of the line discussed above, a containment value of 10 has been assigned. In addition, n o liner exists beneath the sewer line, which has numerous defects. 10 1, Section 3.1.2.1, Table 3- 2, p. 51596 ; 22; 31 Release via overland migration and/or flood: NS NA

Notes: NS Not Scored NA Not applicable

2.4.2 HAZARDOUS WASTE QUANTITY (Ref. 1, p. 51590 )

2.4.2.1.1 Hazardous Constituent Quantity (Tier A) (Ref. 1, pp. 51590, 51591)

De scription

The information available is not sufficient to adequately determine with reasonable confidence a hazardous constituent quantity ( Tier A) for Source 1 , as required by Reference 1, Sect ion 2.4.2.1.1, p. 51590

. Scoring therefore proceeds to the eva luation of Tier B, hazardous wastestream quantity

. Assigned Value: Not Evaluated

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B) (Ref. 1, p. 51591 )

Description

As t he source being evaluated is the historic disposal of PCE

- contaminated condensate fro m the VA Medical Center dry cleaning operation, it is not a source with measurable volume or capacity

. However, since it is known that some quantity of condensate was disposed , a value of greater than zero can be assigned for the hazardous wastestream qua ntity under Tier B, Hazardous Wastestream Quantity, as outlined in Reference 1, Section 2.4.2.1.2 , p

. 51591.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 26 Sum (pounds): > 0

Sum of Wastestream Quantity/5,000 (Table 2

- 5): >0/5,000 = > 0

Hazardous Wastestream Quantity Assigned Value : > 0

2.4.2.1.3 Volume (Tier C) (Ref. 1, p. 51591 )

Description

As a hazardous wastestream quantity has been evaluated

, Tier C has not been evaluated.

Assigned Value: Not Evaluated

2.4.2.1.4 Area (Tier D) (Ref. 1, p. 51591 )

Description

As a hazardous wastestrea m quantity has been evaluated , Tier D has not been evaluated.

Assigned Value: Not E valuated

2.4.2.1.5 Source Hazardous Waste Quantity Value (Ref. 1, p. 51591 )

The source HWQ value for the source is greater than zero, but undetermined, for Tier B – Ha zardous Wastestream Quantity (Ref. 1, Table 2 -5, p. 51591 ).

Source HWQ Value: > 0HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 27 TABLE 3 : Summary of Source Descriptions

Source

No. Source Hazardous Waste Quantity

Value Source Hazardous Constituent

Quantity Complete?

(Y es /N o) Containment Facto r Value by Pathway

Ground water (GW) (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

3.0 GR OUND WATER MIGRATION PATHWAY (Ref. 1, p. 51595 )

3.0.1 GENERAL CONSIDERATIONS (Ref. 1, p. 51595 )

Ground Water Migration Pathway Description

Regional Geology :

Salt Lake Valley is within the Basin and Range physiographic province which is characterized by generally parallel, north - to northeast

- trending mountain ranges separated by broad alluvial basins that are a result of Cenozoic

- age extensional faulting (Ref. 38, p. 4 ). The Salt Lake Valley alluvial basin is bounded on the east by the Wasatch Fault, which is comprised of several seismically

- independent segments that have been active in Holocene time (Ref. 39, p. 3 ). This active fault zone has uplifted the Wasatch Mountains as much as 7,000 feet relative to the valley. The Wasatch Mountains are compr ised of Tertiary

- , Mesozoic - and Paleozoic

- aged bedrock which is present at the surface (Ref. 39, p. 2). The source area of the site is located approximately one mile southwest of the Wasatch Mountains (Figure 1 , Ref s . 38, p. 5 ; 51), above the valley floo r.

The Salt Lake Valley alluvial basin is characterized by unconsolidated Quaternary

- age sediments, overlying unconsolidated and semi

- consolidated Tertiary

- age sediments (Ref. 38, p. 4). T he Quaternary

- age sediments were deposited primarily in lacustr ine and fluvial environments associated with numerous transgressive and regressive phases of the ancestral Lake Bonneville and older lake cycles while t he Tertiary

- age sediments are associated with alluvial fans and volcanic ash and (Refs. 38, p. 4; 39, p. 2, 4, 5). The water level of Lake Bonneville began rising about 30,000 years ago to a high of about 5,180 feet in altitude (approximately 450 feet higher than the site) about 16,000 years ago (Ref. 38, p. 4). This depositional environment resulted in a complex subsurface stratigraphy, with interbedded and laterally discontinuous layers (Refs. 29, p. 24; 38, p. 7; 42, p. 4; 41, p. 5). This complexity is apparent in borehole logs from wells installed at the site (Ref. 20, pp. 40

- 57).

In general, s ediment s deposited near the mountain front ( where the site is located ) tend to be coarser

- grained gravel s and sands with no substantial , continuous layers of fine

- grained materials . F iner

- grained silt s and clay s were deposited in the quieter, deeper water on the valley (lake) bottom (i.e. to the west of the site ) (Ref. 39, p. 4; 41, p p . 4, 5). While borehole logs from wells installed at the site show layers of fine

- grained materials, these layers are not continuous (Ref. 20, pp. 40

- 57).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 28 Regional Hydro g eology :

A generalized model of the basin

- fill sediments in Salt Lake Valley consists of a relatively deep unconfined aquifer near the mountain fronts (i.e. in the area of the site source ) that becomes confined toward the center of the valley by layers of silt and clay (Ref. 38, p, 7). Ground water moves laterally from east to west or southwest in the eastern side of the valley, from the unconfined part of the aquifer towards the confined part o f the aquifer (Refs. 29, pp. 11, 31; 41, pp. 4

- 6). Together, the combi ned unconfined and confined parts of the deep aquifer are known as the ‘principal aquifer’ in the valley. The principal aquifer is an important source of drinking water for Salt Lake Valley, contributing water to about 38% of the population (Ref. 38, pp. 7, 8; 41, p. 7; 42, p. 3).

The primary recharge area for the principal aquifer is near the mountain fronts where there are no continuous layers of fine

- grained material to impede the downward movement of water (Refs. 38, p. 7; 41, pp. 5, 8; 42, pp. 4, 5 ). Leakage of shallow ground water ( i.e. per ched water , also called ‘perched aquifers’ in various reports ) to the principal aquifer is possible where a downward gradient exists and confining layers are thin and discontinuous (Ref. 38, p. 7). These condit ions are present in the secondary recharge area, which borders the primary recharge area on the west, and includes the area of the East Side Springs (Refs. 38, pp.7, 9, 10; 42, p. 4). As ground water in the principal aquifer flows towards the valley center where it is confined beneath laterally continuous fine

- grained layers , an upward gradient is created, and ground water flows upward through the confining layer, into the shallow unconfined aquifer, and finally discharges to the Jord a n River, supply wells , springs, drains, canals, and the Great Salt Lake, or is lost through evapotranspiration (Refs. 38, pp. 7, 8; 42, p. 3).

It should be noted that various reports mention the presence of ‘perched aquifers’ in the area of the site. For ease of discussion in this documentation record, these ‘aquifers’ are referred to within simply as ‘perched water’ or ‘perched zones’, to reinforce the fact that they are discontinuous over short distances, and to distinguish them from the ‘shallow unconfined aquifer’ that overlies laterally continuous fine

- grained layers that exist in the center of the valley (Ref. 38, p. 7).

Depth to ground water in the unconfined part of the principal aquifer (i.e. along the mountain fronts) is typically from 150 to 200 feet bgs (Ref. 41 , p. 11). This correlates well to the depth to water noted in supply and monitoring wells at the site (12 3 .98 to 211.39 feet bgs) (Ref. 29, p. 41). Depth to ground water in the confined part of the principal aquifer is deepest in the secondary recharge a rea (100 to 140 feet bgs), and very shallow (1 to 5 feet bgs) in the discharge area in the center of the valley (Ref. 41, p. 11).

Site G eology and Hydrogeology :

The surficial geology changes from east to west across the site area (Ref. 39, pp. 2, 4). T he surficial geology of the source area of the site is comprised of coarse

- grained alluvial fan deposits of gravel in a matrix of sand and silty sand, surrounded by lacustrine deposits to the south, west and north (Ref. 39, pp. 2, 4). Generally, the lacust rine deposits become more fine

- grained to the west of the site, until the East Bench Fault is reached (Ref. 39, pp. 2, 4). The East Bench Fault , a spur of the Wasatch Fault, branches in two locally, with an eastern branch and a western branch (Refs. 27, p . 3 ; 29, p. 43; 38, pp. 5, 6; 39, p. 2). The western branch of the East Bench Fault is defined by the presence of mixed colluvium and alluvium deposited as a debris apron at the base of the fault’s scarp (Ref. 39, pp. 2, 4). The unconsolidated and underl ying semi

- consolidated sediments beneath the area of site are hundreds of feet thick (Ref. 5, p. 3). At the SLCWS Well # 18 location, bedrock was estimated to occur at approximately 500 feet bgs (Ref. 29, p. 60). According to the driller ’ s log for Univer sity of Utah Well #3, clays and gravels were present to nearly 700 feet bgs (Ref. 40, p. 8).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 29 The topography of the area slopes to the southwest at a grade of approximately 4% until reaching the fault scarp of the western branch of the East Bench Fault (the east branch of the fault is poorly expressed on the surface and does not have a readily apparent scarp), where it steepens abruptly to approximately 10% (Figure 3, Ref. 27, p. 3). It is at this steep scarp that the East Side springs surface (Figure 3, Ref. 27, pp. 3, 4).

The geologic complexity, caused by the various lacustrine and fluvial environments associated with numerous transgressive and regressive phases of the ancestral lakes, is apparent in borehole logs from wells installed at the site in 1998 (Ref. 20, pp. 40

- 57). The closest subsurface boring to the source area of the site is permanent ground water well EPA

- MW

- 05. This well was installed in a boring drilled in July 1998 approximately 300 feet northeast of Building 7 (Figure 3, Refs. 20, pp.11, 12, 23, 37, 38). The log from this boring shows interbedded silt, sands, and gravels present through its entire depth to 220 feet below ground surface (Ref. 20, pp. 50, 51). The logs from the other borings installed in 1998 show similarly complex interbedded lithologies of varying thicknesses that do not correlate well between borings (i.e. that are not laterally continuous) (e.g. Ref. 20, p. 55). In 2005, the USGS attempted to correlate lithology between borings in the area of the contamination, but noted difficulty in matching stratigraphic layers and the discontinuous nature of the fine

grained lower permeability layers identified in the logs (Ref. 24, p. 1).

The site is located approximately one mile southwest of the Wasatch Mountains ( Figu re 1, Refs. 38, p. 5; 51) and overlies the primary recharge area for the principal aquifer (Ref s . 38, pp. 7, 9, 10). The source area (i.e. the site of the historic disposal at the dry cleaner) is located on the western edge of the primary recharge area, wh ere there are no continuous layers of fine

- grained material to impede the downward movement of water to the principal aquifer (Refs. 20, pp. 40

- 57; 38, p. 7; 41, pp. 5, 8; 42, pp. 4, 5). The springs are located in the secondary recharge area where confinin g layers are thin and discontinuous (Refs. 24, p. 1; 38, pp. 7, 9, 10). A ll area s of the site, in particular the source area, are primarily underlain by the principal aquifer ; there are no continuous layers of fine

- grained material to impede flow (Refs. 2 0, pp. 40

- 57; 24, p. 1; 38, pp. 7, 9, 10).

From the Fall of 2010 until early 2012, MWH, on behalf of the SLCDPU, conducted a variety of activities at the site, including aquifer testing and ground water modeling (Ref. 29, pp. 4, 5, 17

- 22, 27

- 33). Pump te sts conducted within SLCWS Well #18 and slug testing in the well EPA

- MW

- 01D yielded an estimated transmissivity for the principal aquifer of 22,700 to 35,800 square feet per day, with hydraulic conductivities 45 to 140 feet per day (Ref. 29, p. 21). Trans missivity is generally highest near the mountains where streams entering the valley deposit the coarsest

- grained materials (Ref. 41, p. 4).

The pump test also identified the East Bench Fault (identified as a potential spur of the Wasatch fault in the
repo rt) ; however, the fault is not a barrier

- type boundary because pumping at SLC Well #18 produced a strong response at the well EPA

- MW

- 1D, indicating a hydraulic connection between these wells (Ref. 29, p. 30). That t he fault is not a barrier to ground water flow is also evidenced by the presence of PCE contaminated ground water downgradient of the fault (Ref. 29, pp. 22, 29

- 30, 46

- 48). As PCE has migrated across this boundary, the fault is not considered to be an aquifer discontinuity for the purposes of scoring the site (Ref. 1, p. 51595).

The ground water modeling predicted ground water flows to be from the northeast to the southwest under steady

- state (no pumping) conditions (Ref. 29, p. 31). MWH attributed the discrepancy between the model’s prediction and the flow direction identified in previous reports (to the northwest) (e.g. Ref. 20, p. 23) to be due to perched water (called ‘perched aquifers’ in the report) (Ref. 29, p. 11). The report further states that the modeled flow direction is physically evident given the known distribution of PCE contamination with high concentrations in the vicinity of the well pair at EPA

- MW

- 01 (i.e. deep and shallow wells) and the detected contamination in springs along the Wasatch Fault line (i.e. the East Bench fault ) (Ref. 29, p. 31).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 30 Conclusions from the ground water modeling included that , if the well were to be used, PCE contamination would continue to impact the w ell as its extraction rate (up to 2,300 gallons per minute (gpm)) would be sufficient to alter the ground water flow regime in the area and draw contamination into the well (Ref. 29, pp. 33, 48). During the MWH study, when pumping SLCWS Well #18, a strong response was noted within EPA

MW

- 1D, indicating a hydraulic connection between these wells (Re f. 29, p. 30). These wells are located approximately 1,600 feet apart (Figure 3, Ref. 27, p. 3)

.
Aquifer Interconnectivity :

The site is located approximately one mile southwest of the Wasatch Mountains (Figure 1, Refs. 38, p. 5; 51) and overlies the pr imary recharge area for the principal aquifer (Refs. 38, pp. 7, 9, 10). The source area (i.e. the site of the historic disposal at the dry cleaner) is located on the western edge of the primary recharge area, where there are no continuous layers of fine

- gr ained material to impede the downward movement of water to the principal aquifer (Refs. 20, pp. 40

- 57; 38, p. 7; 41, pp. 5, 8; 42, pp. 4, 5). The springs are located in the secondary recharge area where confining layers are thin and discontinuous (Refs. 24 , p. 1; 38, pp. 7, 9, 10). A ll areas of the site, in particular the source area, are primarily underlain by the principal aquifer ; there are no continuous layers of fine

- grained material to impede flow (Refs. 20, pp. 40

- 57; 24, p. 1; 38, pp. 7, 9, 10).

G round water moves laterally from the unconfined part of the principal aquifer near the mountains (i.e. at the source area of the site) towards the confined part of the aquifer in the valley center (west of the site), therefore the two parts of the principal aquifer are interconnected (Ref s

. 38, p. 7, 9, 10; 41, p. 4, 5; 42, p. 3 ). A natural downward gradient has been documented within the SLCWS Well #18 at the site (Ref. 29, p. 19).

PCE is very mobile, with relatively low solubility and vapor pressure (Ref s . 32, p. 5 ; 48, p. 4). Once it enters the soil vadose zone (the unsaturated zone)

, PCE travels downward to ground water (Ref. 32, p. 4). I n its liquid state , PCE is heavier and less viscous than water and will sink through it (Ref. 32, pp. 5, 6 ). When P CE encounters an aquitard (i.e. a layer of clay that creates a perched zone ) that is discontinuous (e.g. such as those beneath the site) it is able to flow around the sides of the discontinuous layer in all directions, including in the upgradient direction (depending upon the flow gradient and the topography of the layer) (Ref. 17, pp. 2, 3).

In addition, pumping from the principal aquifer with the local deep water supply wells (e.g. the Mt. Olivet irrigation well, the SLCWS Well #18, and the University of Utah Well # 2 ) has accelerated the natural downward ground water gradient (Ref. 29, p. 19) , causing the contamination to more rapidly spread than would otherwise have occurred (Refs. 17, p. 3; 29, p. 21). When pumped, the ground water extraction rate at SLCWS Well #18 is able to dominate the regional ground water flow ( Ref. 29, p. 21). Aquifer testing and hydrogeological modeling indicate that previous seasonal pumping of SLCWS Well #18 and pumping of the University well laterally expand the contamination to the north, creating a more broad and dilute area of contamination (Ref. 29, p. 28). These wells are all perforated into water bearing zones deeper than 400 feet bgs (Ref. 29, pp. 14, 24, 51; 40, pp. 1, 6, 8, 9).

Aquifer Discontinuity:

The Wasatch Mountains located to the north and east of the site are comprised of Tertiary

- , Mesozoic - and Paleozoic bedrock which is present at the surface (Ref. 39, p. 2). This bedrock forms a different aquifer than those within the unconsolidated basin

- fill sedimen ts present in the valley. Therefore, the base of the Wasatch Mountains will be considered an aquifer discontinuity for HRS scoring purposes and all wells identified beyond this discontinuity will be eliminated.

Faults within and bounding the basin

- fill d eposits may affect the hydraulic gradient and ground water movement (Ref. 41, p. 8). The East Bench Fault, a spur fault of the Wasatch Fault Zone, exists at the westernHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 31 boundary of the currently known extent of ground water contamination (Refs. 27, p. 3, 4; 29, p. 43; 38, pp. 5, 6; 39, p. 2). This fault has two branches in the area of the sit e, with the eastern branch being located approximately 3,200 feet downgradient of the VA Medical Center, while the western bifurcation is located about 5,800 feet dow ngradient (Refs. 27, p. 3 ; 29, p. 43; 38, pp. 5, 6, 39, p. 2). The fault was not modeled as a complete barrier

- type boundary because pumping at SLC Well #18 produced a strong response at the well EPA

- MW

- 1D, indicating a hydraulic connection between these wells (Ref. 29, p. 30). That the fault is not a barrier to ground water flow is also evidenced by the presence of PCE contaminated ground water downgradient of the fault (Ref. 29, pp. 22, 29

- 30, 46

- 48). As PCE has migrated across this boundary, the faul t is not considered to be an aquifer discontinuity for the purposes of scoring the site (Ref. 1, p. 51595).

While no hydrogeologic testing information is available in regards to the western branch of the East Bench Fault, this branch of the fault offsets similar unconsolidated materials as the eastern branch (Ref. 5, p. 3). These sediments are many hundreds of feet thick in the area of the site (Ref. 29, p. 60; 40, p. 8). As it offsets similar unconsolidated sediments as the eastern branch, it follows th at the western branch of the East Bench Fault is also not likely to be a complete barrier to ground water flow. Therefore, this branch of the fault is also not considered to be an aquifer discontinuity for the purposes of scoring the site (Ref. 1, p. 5159 5).

Based upon the evidence presented above, it is considered that an y shallow ground water (e.g. isolated perched water, the East Side Springs) within a 2

- mile radius of the source is connected to the deeper ‘principal aquifer’

. As such, the principal aquifer will be the only hydrologic unit considered f or scoring purpose s (Ref. 1, p. 51595). The principal aquifer is continuous to the south and west of the Wasatch Mountains within the 4- mile radius of t he source , but the bedrock of the Wasatch Mountain s forms a discontinuity to the north and east of the site (Ref s . 1, p. 51 5 95 ; 5).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 32 TABLE 4 : Summary of Aquifer(s) Being Evaluated

Aquifer

Name Is Aquifer Interconnected within 2 miles? (Yes/No) Is Aquifer Continuous within 4

- Mile TDL? (Yes/No) Is Aqu ifer Karst? (Yes/No ) References

Principal Aquifer Yes Yes ( west of the Wasatch Mountains ) No 27 ; 29, pp. 22, 29

- 30, 66; 38, pp.7, 9, 10; 41, pp. 4, 5, 11, 12; 42, p. 4

Notes: TDL Target Distance Limit

3.1 LIKELIHOOD OF RELEASE (Ref. 1, p. 51595 )

3.1. 1 OBSERVED RELEASE (Ref. 1, p. 51595 )

Aquifer Being Evaluated: Principal aquifer

Chemical Analysis

Background Samples :

PCE is a synthetic chemical (Ref. 48 , p. 2 ) and is not ubiquitous in the area of the site

. As such, its background concentration in ground water would be expected to be at or near zero. Nevertheless, chemical analysis will be used to document an observed release of PCE at the site.

Analytical results from both a permanent monitoring well located upgradient of the source (EPA

- MW

- 05 ), as well as historical results from the municipal supply well SLCWS Well #18 from a time when it was uncontaminated (i.e. using SLCWS Well #18 as its own background well)

, will be used to document background levels . Analytical results from each well are discussed separately below.

Background well EPA

- MW

- 05 – well details :

Permanent ground water monitoring well EPA

- MW

- 05 was installed on the VA Medical Center property in August 1998 (Ref

. 20, pp. 12, 37, 38, 50, 51 ). The well is located upgradient of the source (i.e. approximately 300 feet northeast of the former dry cleaner location) (Figure 3, Refs. 20, p. 23; 29, p. 25, 26, 43, 47 ; 51 ).

EPA

- MW

- 05 is completed within the principal aquifer to a depth of 221 feet bgs (4,514 feet amsl)

, and is

s creened from 186 to 221 feet bgs ( 4,549 to 4,514 feet amsl) (Ref. 20, pp. 50, 51 ) . The ground water elevation in the well is similar to those within the other permanent monitoring wells established in the vicinity of the site, as well as the ground water elevatio n within SLCWS Well #18 (Ref. 29, p p. 41 , 66 ; Table s 5 , 7, and 9 of this documentation record ).

Background well EPA

- MW

- 05 – hazardous substance concentrations :

Water collected from EPA

- MW

- 05 has been sampled and analyzed for VOCs numerous times since it s installation in 1998 , always returning non

- detect results for PCE ( Refs. 20, p p

. 25, 79; 23, pp. 6, 49, 50, 64; 24, p p

. 5, 24; 26, pp. 2, 17, 27; 28, pp. 15, 27, 29, 33, 35, 36, 81 ). Three samples will be used to document background conditions for the site: the sample MT

- 007
, collected from well EPA

- MW

- 05 by the UDEQ andHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 33 EPA START on October 15, 2004

, and the sample MW

- 05
, collected from well EPA

- MW

- 05 by EPA START on October 4, 2005

, will be used to document background conditions at the time when SLCWS Well #18 was permanently taken offline due to PCE contamination (approximately October 2004) , and the most recent sample (sample ID: H0AA4) collected from EPA

- MW

- 05 on November 16, 2011 will also be used to document current background conditions at the s ite (Refs . 26, pp. 2, 17, 27 ; 28, pp. 15, 27, 29, 33, 35, 36, 81 ; 46; Table 6 of this documentation record ).

The sampling performed on October 15, 2004 was conducted through a Cooperative Agreement between the EPA and the UDEQ (Ref. 23, p. 3). A backgrou nd sample was collected from permanent monitoring well EPA

- MW

- 05 (sample ID: VA Hosp EPA

- MW -05 ( MT

- 007) ) and release samples were collected from the permanent monitoring well EPA

- MW

- 01D, the Mount Olivet irrigation well

, and SLCWS Well #18 (Ref. 23,
pp. 4 , 6, 64). Quality assurance/quality control (QA/QC) samples collected included a duplicate sample from the Mount Olivet well (sample ID: Mt Olivet Well

- B) (Ref. 23, pp. 6, 41

, 64), a field blank (sample ID: Mt Olivet Well

- C) (Ref. 23, pp. 43, 64) and a t rip blank (sample ID: Mt

- Olivet Well

- D) (Ref. 23, pp. 45, 64). Samples were shipped to the EPA Region 8 Laboratory i n Golden, Colorado and analyzed for volatile organics using EPA Method 8260 (Ref. 23, pp. 31, 32, 35). The analytical results from the EPA

- MW

- 05 sample (sample ID: VA Hosp EPA

- MW

- 05 (MT

- 007)) did not reveal any detections of PCE above the analytical method reporting limit ( MRL ) value s of 1 μg/L for either analyte, indicating that water from this upgradient location was not contamin ated abov e this concentration (Ref. 23, pp. 49, 50, 64). The data were reviewed according to the EPA Document “USEPA Contract Laboratory Program National Functional Guidelines for Organic Data Review, October 1999” (Ref. 58 ) by a n EPA START chemist in September 20 05 and found to be acceptable for use with the qualifications noted in the data validation report (Ref. 23, pp. 65, 66). A draft report was prepared and both the chain

- of

- custody and the laboratory sample receipt narrative are available (Ref. 23, pp. 1

- 10 , 35, 64).

The sampling conducted on October 4, 2005 was conducted by EPA START (Ref. 26). A background sample was collected from permanent monitoring well EPA

- MW

- 05 and release samples were collected from permanent monitoring wells EPA

- MW

- 02, EPA

- MW

- 01 D, and EPA

- MW

- 04 (Ref. 26, pp. 1

- 6, 27). QA/QC sample s collected included a trip blank (sample ID: TB

- 01) and a duplicate sample collected from EPA

- MW

01D (sample ID: MW

- 11) (Ref. 26, pp. 1

- 6, 27). Samples were delivered by hand to Data Chem Laboratorie s in Salt Lake City for volatile organic analysis by EPA Method 524.2 (Ref. 26, p p. 6, 9, 27 ). The analytical results from the EPA

- MW

- 05 sample (sample ID: MW

- 05) did not reveal any detections of PCE above the sample

- specific Method Detection Limit (MDL ) v alue of 0. 110 μg/L , indicating that water from this upgradient location was not contaminated above this concentration (Ref. 2 6, pp. 16, 17). The data were reviewed according to the EPA Document “USEPA Contract Laboratory Program National Functional Guidel ines for Organic Data Review , October 1999 ” by a n EPA START chemist in March 2012 and found to be acceptable for use with the qualifications noted in the data validation report (Ref s . 26, p. 7 ; 58 ).

The sampling conducted in November 2011 was conducted by UDEQ and EPA START (Ref. 28, p p . 9, 41

- 53 ). A background sample was collected from permanent monitoring well EPA

- MW

- 05 on November 16 and release samples were collected from the permanent monitoring well EPA

- MW

- 01S, from five newly

- placed direct

- push bor ings, from water from the fountain at Liberty Park and from the 8 th South artesian well (aka 8 th South Well) during November 14 -1 7 (Ref. 28, pp. 9, 35). A sample was collected from EPA

- MW

- 05 on December 21, 2011 (Ref . 28, p p. 9, 35)

. Ground water QA/QC samples collected included four trip blanks (ESS

- GW

- 12, ESS

- GW

- 32, ESS

- GW

- 33, ESS

- GW

- 34) a rinsate blank (ESS

- GW

- 13), a laboratory duplicate (ESS

- GW

- 11), and a field duplicate (ESS

- GW

- 14) (R ef. 28, pp. 17, 18, 32, 3 6 ).

S am ples were delivered on November 17 and December 21, 2011 via Federal Express to the EPA Contract Laboratory Program (CLP) laboratory Mitkem Laboratories (Spectrum Analytical), in Warwick, Rhode Island for volatile low/medium multi

- media, multi

- concentration organics analysis - SOM01.2 (R ef. 2 8, pp. 59

- 62,HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 34 64, 112, 130). The analytical results from the EPA

- MW

- 05 sample (sample ID: HOAA4) did not reveal any detections of PCE above the CRQL value of 5 .0 μg/L , indicating that water from this upgradient location was not contaminated above thi s concentration (Ref s

. 28, pp. 15, 25, 33, 35, 81 ). The data were reviewed according to the EPA Document “USEPA Contract Laboratory Program National Functional Guidelines for Superfund O rganic Methods Data Review, June 2008 ” by a n EPA START chemist in January 2012 and found to be acceptable for use with the qualifications noted in the data validation report ( Ref . 2 8 , p p

. 18, 63

- 72, 112

- 119, 130

- 137).

TABLE 5 : Background Ground Water Sample and Well Information (EPA

- MW

- 05) – Principal Aquifer

Sample I D Well Depth (feet amsl) Screened Interval (feet amsl) Ground Water Elevation* (feet amsl) Sample Date References

VA Hosp EPA

MW

- 05 ( MT

- 007 ) 4,514 4,549 to 4,514 4,524 10/15/2004 20, p. 25, 79; 23, pp. 1, 3, 6, 49, 50, 64;

29, p p. 41 , 66 MW

- 05 “ “ “ 10 /4/2005 20, p. 25, 79; 26, pp. 2, 17, 27; 29, p p. 41
, 66 H0AA4 “ “ “ 11/16/2011 20, p. 25, 79; 28, pp. 28, pp. 15, 25, 33, 35, 81; 29, p p. 41
, 66

Notes: Amsl above mean sea level ID identification number * Ground water elevation data is taken from Ref. 2 9 (pp. 41, 66) as this is the only site study available where concurrent water levels were collected from all site wells of interest (i.e. Mt. Olivet well, Well #18, and the EPA monitoring wells), allowing for comparison between wells.

TABLE 6 : Backgro und Ground Water Sample Concentrations (EPA

- MW

- 05) – Principal Aquifer

Sample ID Sample Date Hazardous Substance Concentration ( μg/L ) Reporting Limit ( μg/L ) References

VA Hosp EPA

- MW

- 05

(MT

- 007) 10/15/2004 PCE <1.0 1.0 23, pp. 1, 3, 4, 6, 31, 32, 35 , 49, 50, 64

- 66

MW

- 05 10/4/2005 PCE <0. 110 0. 110 * 26, pp. 1

- 7, 16, 17, 27, 58 H0AA4 11/16/11 PCE <5 .0 U 5 .0 ** 28, pp. 15, 25, 33, 35, 81

Notes: μg/L micrograms per liter * sample

- specific method detection limit

** Contract Required Quantitation L imit U The analyte was not detected above the reporting limitHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 35 SLCWS Well #18 (as its own background well) :

SLCWS Well #18 was installe d near the northeast corner of 500 South and 1 500 East (now called Guardsman Way) in October 1 956 ( Figure 3, Ref. 40, pp. 1, 9 ). The well, assigned Water Right No. 57

- 2697, was installed to supply culinary (municipal) water to Salt Lake City (Ref s. 40, pp. 1, 9; 52, pp. 8, 12, 24

- 26 ) . The well has been referred to by various names, including the 500 South Well, 15 th Eas t Well, Well #1061A, and SLC Drinking Water Well #18 (Refs. 29, p. 1; 52, pp. 8, 12, 24

- 26 ). The well is located approximately 2,200 feet northwest of t he source and approximately 2,300 feet northwest of EPA

- MW

- 05 ( Figure 3, Refs. 40, pp. 1, 9; 51 ).

SLCW S Well #18 is completed within the principal aquifer to a depth of 510 feet bgs (4,164 feet amsl) , being perforated from 266 to 470 feet bgs (4,4 08 to 4, 204 feet amsl) (Ref s. 29, pp. 13, 41; 40, p. 9 ) (Note that Ref. 29, p. 41 contains a typo in the table. The correct number for the top of the perforations, according to the original well log, is 266 feet (Ref. 40, p. 9))

. The ground water elevation in the well is similar to those within the permanent monitoring wells established at the site (Ref. 29, p p

. 41 , 66 ; Table s 5, 7, and 9 of this documentation record ).

TABLE 7 : Background Ground Water Sample and Well Information (SLCWS Well #18) – Principal Aquifer

Sample ID Well Depth (feet amsl) Perforated Interval (feet amsl) Ground Water Elevation* (feet amsl) Sample Date References

500 So 1500 East 7/21 4,164 4,4 0 8 to 4,204 4,491 07/21/1989 29, pp. 41, 51, 52, 66 ; 40, pp. 9, 10; 45
, p. 2 1500 E Well “ “ ” 09/20/1994 29, pp. 41, 51, 52, 66; 40, pp. 9, 10 ; 45, p. 5

Notes: Amsl above mean sea level ID i dentification number * Ground water elevation data is taken from Ref. 29 (p p . 41, 66 ) as this is the only site study available where concurrent
water levels were collected from all site wells of interest (i.e. Mt. Olivet well, Well #18, and the EPA monitoring wells)

, allowing for comparison between wells.

Background h istoric analytical results from SLCWS Well #18:

Under the Safe Drinking Water Act (SDWA) , enacted in 1974 and amended in 1996, the SLC WS is responsible for the sampling and analysis (monitoring) of its water supplies in order to ensure that drinking water quality meets minimum standards (MCLs) established under the law. Analytical results from this compliance sampling show that the SLCWS Well #18 was free of PCE contamination until 1997, wh en the first detection wa s recorded (Ref. 45, pp. 1

- 5).

Two sets of analytical results from samples collected prior to 1997 have been received from the Water Quality and Treatment Administrator for the SLCDPU (Ref. 45, p. 1

- 5). Specific details on sampling procedures were
not provided. A sample collected by the SLCWS on July 21, 1989 was analyzed for SDWA List One, Two, and Three organic compounds by American West Analytical Laboratories in Salt Lake City using EPA Method 504 (Ref. 45, pp. 2

- 4). Result s from this sample did not reveal any detection of PCE above the detection limit value of 0 .5 μg/L , indicating that water from the well was not contaminated with PCE above this concentration (Ref . 45, p. 2; Table 8 of this documentation record). A sample collected by the SLCWS on September 20, 1994 was analyzed for SDWA Regulated, List 1, and List 3 organic compounds by the Utah Division of Laboratory Services in Salt Lake City using EPA Method 502.2 (Ref. 45, p. 5). Results from this sample didHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 36 not revea l any detection of PCE above the MDL value of 0.5 μg/L , indicating that water from the well was not contaminated with PCE above this concentration (Ref . 45, p. 5 ; Table 8 of this documentation record ).

TABLE 8 : Background Ground Water Sample Concentrations (SLCWS Well #18) – Principal Aquifer

Sample ID Sample Date Hazardous Substance Concentration ( μg/L ) Reporting Detection

Limit ( μg/L ) References

500 So 1500 East 7/21 07/21/1989 PCE <0.5 0.5 * 45, p. 2

1500 E Well 09/20/1994 PCE <0.5 U 0.5 ** 45, p. 5

Notes: μg/L micrograms per liter * detection limit

** sample specific method detection limit NA not applicable U The analyte was not detected above the reporting detection limit

Contaminated Samples:

Ground water samples listed in Table s 9 and 10 , and shown in Figure 3

, of this HRS documentation record were collected from permanent monitoring and supply wells completed in the principal aquifer underlying and in the vicinity of t he source during two time periods: in 2004/2005 ( at the time of and within one year of when SLCWS Well #18 was shut down due to PCE contamination ) , and in November and December 2011, in order to assess the current contamination conce ntrations at the site ( Refs. 23 , p. 3 ; 26 , pp. 1

- 6, 27 ; 28 , p. 9 ).

T he sampling performed on October 15, 2004 was conducted through a Cooperative Agreement between the EPA and the UDEQ (Ref. 23, p. 3). A background sample was collected from permanent monitoring well EPA

- MW

- 05 (sample ID: VA Hosp EPA

- MW

- 05 (MT

- 007)) and r elease samples were collected from the permanent monitoring well EPA

- MW

- 01D, the Mount Olivet irrigation well, and SLCWS Well #18 (Ref. 23, pp. 4 , 6, 64). All wells are completed in the same aquifer at similar depths (Ref. 29, p. 41). UDEQ and EPA – 2004:

Quality assuran ce/quality control (QA/QC) samples collected included a duplicate sample from the Mount Olivet well (sample ID: Mt Olivet Well

- B) (Ref. 23, pp. 6, 41, 64), a field blank (sample ID: Mt Olivet Well

C) (Ref. 23, pp. 43, 64) and a trip blank (sample ID: Mt -O livet Well

- D) (Ref. 23, pp. 45, 64).

Samples were shipped to the EPA Region 8 Laboratory in Golden, Colorado and analyzed for volatile organics using EPA Method 8260 (Ref. 23, pp. 31, 32, 35). The data were reviewed according to the EPA Document “USEPA Contract Laboratory Program National Functional Guidelines for Organic Data Review, October 1999” (Ref. 58) by a n EPA START chemist in September 2005 and found to be acceptable for use with the qualifications noted in the data validation report (Ref. 23, pp. 65, 66). A draft report was prepared and both the chain

- of

- custody and the laboratory sample receipt narrative are available (Ref. 23, pp. 1

- 10, 35, 64)

. The analytical results from the background sample have been discussed previously. Analytical r esults from the samples found to be contaminated are presented in Table 10 of this documentation record. PCE was detected in all three of the downgradient wells with PCE concentrations ranging from 2.23 μg/L in SLCWS Well #18 to 128 μg/L in the Mt Olivet Well (Ref. 23, pp. 6, 38, 40, 42, 48).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 37 The analytical results from the blank samples did not reveal any detections of PCE above the MRL value of 1 μg/L , showing that potential cross contamination during either field activities or sample handling and shi pment did not occur (Ref. 23, pp. 36, 43

- 46).

The sampling conducted on October 4, 2005 was conducted by EPA START (Ref. 26). A background sample was collected from permanent monitoring well EPA

- MW

- 05 and release samples were collected from permanent monitoring wells EPA

- MW

- 02, EPA

- MW

- 01D, and EPA

- MW

- 04 (Ref. 26, pp. 1

- 6, 27). All wells are completed in the same aquifer at similar depths (Ref. 29, p. 41). EPA START – 2005:

QA/QC samples collected included a trip blank (sample ID: TB

- 01) and a duplicate sample collected from EPA

- MW

- 01D (sample ID: MW

- 11) (Ref. 26, pp. 1

- 6, 27).

Samples were delivered by hand to Data Chem Laboratories in Salt Lake City for volatile organic analysis by EPA Method 524.2 (Ref. 26, p. 6, 9, 26, 27). The data were reviewe d according to the EPA Document “USEPA Contract Laboratory Program National Functional Guidelines for Organic Data Review, October 1999” by a n EPA START chemist in March 2012 and found to be acceptable for use with the qualifications noted in the data vali dation report (Refs. 26, p. 7; 58). While a narrative report covering the field sampling event is not available, t he field logbook and chain

- of

- custody records are included in the reference (Ref. 26, pp. 1- 5, 27).

The analytical results from the backgrou nd sample have been discussed previously. Analytical results from the samples found to be contaminated are presented in Table 10 of this documentation record. PCE ranged from

non

- detect in background well EPA

- MW

- 05 (at a sample

- specific method detection limit of 0. 110 μg/L ) (Ref. 26, p p

. 2, 6, 16, 17 , 27 ) to 160 μg/L in EPA

- MW

- 02 (Ref. 26, p p

. 3, 6, 18, 19
, 27 ).

The analytical results from the blank sample did not reveal any detections of PCE above the sample

- specific method detection limit of 0. 110 μg/L , showing that potential cross contamination during either field activities or sample handling and delivery did not occur (Ref. 26, p p. 6, 14, 15 , 27 ).

The sampling conducted in November 2011 was conducted by UDEQ and EPA STAR T (Ref . 28, p p

. 9 , 41

- 53 ). A background sample was collected from permanent monitoring well EPA

- MW

- 05 on November 16 and release samples were collected from the permanent monitoring well cluster EPA

- MW

- 01S and EPA

- MW

- 01D, as well as from five newly

- placed direct

- push borings, and water from the fountain at Liberty Park and the 8 th South artesian well (aka 8 th South Well) from November 14

- 16 and also December 21, 2011 ( Ref. 28, pp. 9, 35 ). UDEQ and EPA START – 2011:

G round water samples collected from permanent wells are used to e stablish an observed release to ground water at the site. Analytical results from the samples found to be contaminated are presented in Table 10 of this documentation record.

Ground water QA/QC samples collected included four trip blanks (ESS

- GW

- 12, ES S- GW

- 32, ESS

- GW

- 33, ESS

- GW

- 34) a rinsate blank (ESS

- GW

- 13), a laboratory duplicate (ESS

- GW

- 11), and a field duplicate (ESS

GW

- 14) ( R ef. 28, pp. 17, 18, 32, 36 ).

Samples were delivered on November 17 and December 21, 2011 via Federal Express to the EPA C ontract Laboratory Program (CLP) laboratory Mitkem Laboratories (Spectrum Analytical), in Warwick, Rhode Island for volatile low/medium multi

- media, multi

- concentration organics analysis - SOM01.2 ( Ref. 2 8, pp. 59

- 62, 64, 112, 130 ). The data were reviewed according to the EPA Document “USEPA Contract LaboratoryHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 38 Program National Functional Guidelines for Superfund Organic Methods Data Review, June 2008” by a n EPA START chemist in January 2012 and found to be acceptable for use with the qualifications noted in the data validation report ( Ref. 28, pp. 18, 63

- 72, 112

- 119, 130

- 137).

The analytical results from the background sample collected from well EPA

- MW

- 05 are discussed above

. Analytical results for the samples collected from the existing permanent moni toring wells confirm the presence of PCE contamination in ground water (Ref. 28, pp. 14, 15, 19, 27, 29, 33, 35, 58, 73, 139, 143 ). Concentrations of PCE in the existing wells ranged from a non

- detect (at the CRQL of 5 μg/L ) in the background well EPA

- MW

- 05 to 150 μg/L in well EPA

- MW

- 01S (Ref. 28, pp. 14, 15, 19, 27, 29, 33, 35, 73, 81 ).

The analytical results from the blank samples did not reveal any detections of PCE above the CRDL value of 5.0 μg/L , showing that potential cross contamination during either field activities or sample handling and delivery did not occur ( Ref. 28, pp. 17, 18, 36, 91, 93, 97, 99, 141 ).

TABLE 9 : Observed Release Ground Water Sample Information – Principal Aquifer

Well Sample ID (s) Well Depth

(feet amsl) Screened / Perforated

Interval (feet amsl) Ground Water Elevation (feet amsl) Sample Date(s) References

EP A- MW

01S HOAA1 4,441 4,48 1 – 4,441 4,508 11/14/11 20, pp. 40 , 41 , 42 ; 29, p. 41 ; 28, pp. 14, 15, 19, 27, 29, 33, 35, 73 ; 51

EPA

- MW

01D EPA

- MW

- 01D, MW

- 01, HOAB9 4,26 1 4,301 – 4,261 4,493 10/15/04, 10/05/05

, 12/21/11 20, pp. 43; 23, pp. 6, 38, 64; 26, pp. 3, 6, 20; 28,
pp. 14, 15, 19, 27, 29, 33, 35, 139 ; 29, p. 41 ; 51

EPA

- MW

- 02 MW

- 02 4,475 4
, 505

– 4, 475 4, 516 10/04/05 20, p. 45; 26, p p

. 3, 18, 19 , 27 ; 29, p. 41 ; 51

EPA

- MW

- 04 MW

- 04 4,484 4,514 – 4,484 4, 520 10/05/05 20, p. 49; 26, pp. 4, 24, 25, 27; 29, p. 41 ; 51
SLCWS Well #18 SLCDW Well #18 4,164 4,448 – 4,204 4, 491 10/15/04 23, pp. 6, 47, 64; 29, p. 41 ; 40, p. 9; 51

Mt Olivet W ell Mt Olivet W ell

A 4,180 4,468

– 4 ,180 unknown 10/15/04 23, pp. 6, 39, 64 ; 29, p. 41 ; 40, p. 6; 51

Notes: Amsl above mean sea level NA not applicableHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 39 TABLE 10 : Observed Release Ground Water Sample Concentrations – Principal Aquifer

Sample ID Sample Date Hazardous Substance Concentrati on ( μg/L ) Reporting Limit ( μg/L ) References

HOAA1 11/14/11 PCE 150 5 .0* 28, pp. 1 4, 29, 33, 35, 58, 60, 64, 73 EPA

- MW

- 01D 10/15 / 04 PCE 8.33 1 23, pp

. 37, 38, 64 HOAB9 12/21/11 PCE 12 5 .0* 28, pp. 14, 15, 19, 27, 29, 33, 35, 139 MW

- 02 10/04/05 PCE 160 0. 110** 26, pp. 3, 18, 19, 27
, 28
MW

- 04 10/05/05 PCE 120 0.110** 26, pp. 4, 24, 25, 27
, 28
SLC DW Well # 18 10/15/04 PCE 2.23 1 .0* 23, p p

. 47, 48, 64

Mount Olivet 10/15/04 PCE 128 1 23, p. 39, 40, 64

Notes: * CRQL

** sample

- specific me thod detection limit μg/L micrograms per liter PCE Tetrachloroethe ne

Hazardous Substances Released :

Tetrachloroethylene ( PCE )

Ground W ater Observed Release Factor Value: 550

Other Supporting Data

Sampling of springs downgradient of the Mt. Olivet we ll conducted by the SLCPDU in 2010 revealed concentrations of PCE in six of the springs as high as 40.4 μg/L (Figure 3, Refs . 27, p p . 14, 25, 32, 45, 46 ; 28, pp. 8, 9 ). Given the springs’ locations downgradient of the known PCE contamination within the Mt. Olivet well and the EPA monitoring wells, the existing PCE contamination in ground water was considered the likely source of the PCE ( Ref. 28, pp. 6, 19 ).

The UDEQ conducted a follow

- on investigation in late 2011 which involved the collection of addi tional water samples from springs, as well as samples of ground water from five newly

- placed direct

- push borings (Refs. 28, pp. 9 , 13 ; 52, pp. 68, 69). Analytical results from the UDEQ samples confirmed the presence of PCE contamination in two of the spri ngs, as well as ground waters adjacent to the springs. Concentrations of PCE in the springs ranged from a non

- detect in one spring (at the CRQL of 5 μg/L), to 20 μg/L (Ref . 28, pp. 16, 28, 33, 37, 101, 103, 105). PCE was detected in two direct

- push borin gs at concentrations of 6.1 μg/L and 8 μg/L (Ref . 28, pp. 14, 19, 27, 29, 33, 35, 83, 85 ).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 40 Attribution :

It has been documented that PCE was the solvent used at the VA dry cleaning facility (Ref. 8, pp. 2, 3). The dry cleaning system was a closed loop system (Refs. 8, p. 2, 3; 10, p. 7). The system contained a distillation process for the recovery of PCE at the end of each cycle (Ref. 8, p. 2, 3). The VA reported that there was no documentation to support that they ever had below or above ground tanks used for storing spent solvents, chlorinated solvents, waste fluids or materials containing spent chlorinated solvent (Ref. 8, p. 3). The condensate from the distillation process was emptied directly into a drain line attached to the sanitary sewer (Ref. 8, p. 2, 3).

While an exact hazardous waste quantity of PCE disposed into the drain line cannot be determined, it is known that condensate (aka separator water) contains PCE, being saturated with respect to the solvent (Ref s . 10, pp. 11

- 13; 11, pp. 2

- 7). At room temperature, approximately 150 mg/L of PCE would have been dissolved in the separator water (Ref s . 10, p. 12; 11, p.4, 5). In addition to condensate water with dissolved PCE, the discharge would also have contained some pure cleaning solvent and solids containing PCE (Ref. 32, p. 4). Being heavier than water, PCE settles to the bottom of the sewer line and exfiltrates through it, leaking through joints and cracks (Ref. 32, p. 4). Exfiltration rates from clay sewer pipes in some areas of the U.S. have been estimated to be between approximately 5,000 and 77,000 gallons per inch diameter of pipe, per mile length, per day (Ref. 60, pp. 4

- 6). PCE, being volatile, also turns into gas and penetrates the sewer wall. PCE then travels through the vadose zone to the ground water (Ref. 32, p. 4).

According to the VA, the distillation process was efficient enough that very little PCE was added to the system on a weekly basis for recharge (Ref. 8, pp. 2, 3). PCE was purchased and stored in 55

- gallon contai ners. The rate at which the 55

- gallon containers were used is unknown (Ref. 8, p. 2, 3), but PCE consumption per weight of material cleaned has been reported to vary from 420 pounds of material per gallon to less than 100 pounds of material per gallon, de pending upon the overall performance of the dry cleaning equipment and the effectiveness of operating procedures (Ref. 16, p. 5). It has also been reported that, in the early 1990’s a typical dry cleaner business used between 15 and 40 gallons a month of PCE (Ref. 32, p. 5).

The disposal of dry cleaner separator water to a sanitary sewer or septic tank was common practice in the 1980’s (Ref. 10, p. 15). One study has shown that the most frequent type of release from dry cleaners is a release from sewer l ines (Ref. 33, p. 4).

PCE has been detected in soil gas above the sanitary sewer line that leads from the former location of the dry cleaner within Building 7, with the highest concentrations detected at locations closest to Building 7 (Refs. 12, pp. 6

- 7, 13

- 16; 13, pp. 4, 6, 7, 9, 14). The presence of PCE in soil gas confirms that the soil has been impacted by PCE.

Employees of the SLCDPU documented observations of discolored water and odors of dry cleaner solvent at various dates in the early 1980’s while cleaning the sanitary sewer line that leads from Building 7 (Ref. 14). A video survey of sections of the sewer lines between Building 7 and Sunnyside Avenue was conducted on December 17, 2003 by the SLCDPU (Ref. 15). This survey documented numerou s defects in most of the sewer line sections, including cracks, root penetrations, offsets, and a pipe sag, as well as evidence of historic breaks, repairs and replacements of the clay pipe (Ref. 15). Waste water, free

- phase solvent, and solvent
vapors ca n leak from sewer lines through cracks, joints or breaks (Refs. 10, p. 16; 32, pp. 3

- 4; 33, pp. 4

- 5). There is no liner situated between the sewer line and the underlying in

- situ soils (Ref. 31). Soil gas above the sanitary sewer line was sampled for PCE i n 1996 and again in 2006 (Refs. 12, 13). Despite the tests being conducted at least 12 and 22 years, respectively, after the dry cleaner was removed from service, and that PCE vapors tend to sink rather than rise through soil (Ref. 32, p. 6), PCE was dete cted in soil gas atHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 41 some locations above the sanitary sewer line. The highest concentrations were detected at locations closest to Building 7 (Refs. 12, pp. 6, 7, 13

- 16; 13, pp. 4, 6, 7, 9, 14).

The source area (i.e. the site of the historic disposal at the dry cleaner) is located on the western edge of the primary recharge area, where there are no continuous layers of fine

- grained material to impede the downward movement of water to the principal aquifer (Refs. 20, pp. 40

- 57; 38, p. 7; 41, pp. 5, 8; 42, pp. 4, 5). The springs are located in the secondary recharge area where confining layers are thin and discontinuous (Refs. 24, p. 1; 38, pp. 7, 9, 10). A ll areas of the site, in particular the source area, are underlain by the principal aquifer as the gr ound water beneath the site is interconnected with the principal aquifer; there are no continuous layers of fine

- grained material to impede flow (Refs. 20, pp. 40

- 57; 24, p. 1; 38, pp. 7, 9, 10).

PCE is very mobile, with relatively low solubility and vapo r pressure (Refs. 32, p.5; 48, p. 4). Once it enters the soil vadose zone (the unsaturated zone), PCE travels downward to ground water (Ref. 32, p. 4). In its liquid state, PCE is heavier and less viscous than water and will sink through it (Ref. 32, pp. 5, 6). When PCE encounters an aquitard (i.e. a layer of clay that creates a perched zone) that is discontinuous (e.g. such as those beneath the site) it is able to flow around the sides of the discontinuous layer in all directions, including in the
upgra dient direction (depending upon the flow gradient and the topography of the layer) (Ref. 17, pp. 2, 3).

Ground water and springs downgradient of Building 7 and the sanitary sewer line contain PCE at concentrations significantly above background levels ( Refs. 20, p. 13, 25, 27 , 67, 69, 79; 21, pp. 6, 11, 15; 22,
pp. 18, 45, 47; 23, pp. 6, 38, 40, 42, 48; 24, pp. 5

- 33; 25, pp. 2

- 5; 26, p. 17, 19; 27, pp. 2

- 4, 7, 10, 13, 18, 21, 24, 29, 32, 35, 38, 41, 44 ; 28, pp. 6, 8, 9, 14, 16, 18, 19, 27, 28, 29, 33, 35

- 37, 58, 73, 79, 83, 85, 103, 105, 142 ; 29, pp. 18

- 22). Ground water collected from the well EPA

- MW

- 05 located immediately upgradient of the former dry cleaner location is not contaminated with PCE (Refs. 23, pp. 1, 3, 4, 6, 31, 32, 35, 49, 50, 64

- 66; 26, pp. 1- 7, 16, 17, 27, 58; 28, pp. 15, 25, 33, 35, 81 ). The well EPA

- MW

- 01D is contaminated with PCE and is located directly downgradient of t he source (Refs. 23, pp. 37, 38, 64; 28, pp. 14, 15, 19, 27, 29, 33, 35, 139). A hydraulic connection between EPA -MW- 01D and the municipal well SLCWS Well #18 has been established through aquifer testing (Ref. 29, p

. 30).

In 2012, the EPA engaged Toeroek Associates, Inc. (Toeroek) to conduct a survey of businesses or facilities that have operated in the area of the si te (Ref. 6, p. 1). The purpose of the survey was to identify any current or historic businesses or facilities in the area that may be of potential environmental concern (Ref. 6, pp. 1

- 3). The area searched included a one mile buffer around the current kn own extent of PCE contamination in ground water (Ref. 6, pp. 1, 59, 60). In addition to businesses known to use PCE (e.g. dry cleaners), any business that had the potential to handle and/or release wastes into the environment (as identified based on Stand ard Industrial Classification (SIC) codes) was listed in the search results as a business ‘...with potential to impact the site plume’ (Ref. 6, p. 3). These businesses were not limited to those that used chlorinated solvents, let alone PCE (Ref. 6, p. 3). A separate database (Environmental Data Resources, Inc. [EDR] ) that compiles regulatory listings and violations (such as from the CERCLIS and Resource Conservation and Recovery Act (RCRA) databases) was also searched in order to identify business that pote ntially used, generated, or received PCE specifically; or used PCE in their products (Ref. 6, p. 3). Businesses such as dry cleaners and auto repair facilities that were deemed to have used chlorinated solvents and parts cleaners were also identified from this database as potential contributors to the contamination (Ref. 6, p. 3). Relevant businesses were linked to addresses through Salt Lake County parcel data and plotted on maps (Ref. 6, pp. 3, 59, 60 ).

Toeroek subsequently performed additional resea rch (e.g. of the UDEQ LUST and UST databases) on a smaller number (40) of facilities located in or within close proximity to the contamination, or upgradient of the contamination, an attempt to obtain more detailed information about the facilities’ operati ons and waste streams (Ref. 6, pp. 30

- 58 ).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 42 The VA Medical Center is identified as Map ID # 19 in the report , and the location of the former VA Medical Center dry cleaner is denoted on the reports figures by a blue star (Ref. 6, pp. 9, 36, 49, 59, 60 ). The former name of the site itself, the ‘Mount Olivet Cemetary [sic] Plume’ is shown as Map ID #1 (Ref. 6, pp. 5, 59, 60 ).

The results of the survey indicated that no relevant businesses or facilities of potential environmental concern exist between the f ormer dry cleaner at the VA Medical Center Building 7 and the downgradient contaminated wells EPA

- MW

- 02, EPA

- MW

- 04, EPA

- MW

- 03, EPA

- MW

- 01D and EPA

- MW

- 01S (Ref. 6, pp. 59, 60 ). In addition, no dry cleaners were identified upgradient of Building 7 and the se wer line (Ref. 6, pp. 59, 60 ).

Businesses or facilities located upgradient of Building 7 and the sewer line

Eleven businesses or facilities located between 0.5 and 1 miles upgradient of Building 7 were identified as being of potential environmental con cern (Map ID #’s 34, 35, 64, 65, 66, 67, 68, 69, 70 , 118, 119 ) (Ref. 6, pp. 12, 18

- 20
, 35, 37

- 39, 42, 51, 54

- 60 ). Of these eleven

, eight of the businesses (Map ID #’s 34, 64, 65, 66, 67, 68 , 118 and 119 ) were listed in the search results based on SIC code s (Ref. 6, pp. 8, 18, 19, 35, 37

- 39 , 50, 54

- 56 , 58

- 60 ). Upon further research, all eight of these businesses were considered to be unlikely sources of contamination (Ref. 6, pp. 35, 37

- 39 , 50, 54

- 56, 58 ).

The remaining three (Map ID #’s 35, 69 and 70) w ere included based on regulatory listings and are discussed in further detail below (Ref. 6, pp. 3,12, 19, 20, 37, 42 ).

The Underground Storage Tank (UST) Branch of the UDEQ has records concerning the suspected release of diesel from a UST located at the University of Utah Heartport Research Center (Ref. 34, pp. 12

- 13). The University was required to conduct an investigation of the suspected release (Ref. 6, p. 13). Upon review of the information submitted by the University to the UDEQ, the UDEQ issued a letter stating that any detected petroleum contamination at the site was not a threat to human health or the environment and recommended that no further action be taken (Ref. 34, p. 12). No record s of the tank also holding PCE or solvents were located in UDEQ records. University of Utah Heartport Center (Map I D # 35) (Refs. 6, pp. 12, 37, 51, 59, 60; 34, pp. 12, 13)

The University of Utah acquired land from the Fort Douglas Military Reservation beginning in 1948 (Ref. 61, p. 7). Building 515 was used by the University as a hazardous waste storage area between 1980 and 1993 (Ref. 61, p. 7). University of Utah Building 515 (formerly the Fort Douglas Military Reservation) (Map ID #’s 69, 70) (Refs. 6, pp. 19, 20, 42, 57, 59, 60; 34, pp. 1, 2, 5; 61, pp. 1, 7)

During a soil gas investigation conducted by EPA START in November, 1996, PCE contamination was noted in a soil gas sample collected from near Building 515 (Ref. 13, pp. 3, 4, 6, 7, 14). Due to the limited scope of the investigation, the UDEQ per formed additional soil gas sampling in July and August, 2001 (Ref. 61, p. 5). Ground water sampling was not performed (Ref. 61, p. 13). The results of this subsequent investigation showed the presence of various VOCs, including PCE, at numerous sampling locations around the building (Ref. 61, pp. 13

- 15, 25

- 39). 1 ,1,1- Trichloroethane (TCA) was the most widespread contaminant found (Ref. 61, p. 13).

The location of Building 515 is approximately one mile up

- gradient of the VA Medical Center Building 7 (R ef s . 13, p. 6 ; 61. P. 16 ). Although this study did not collect ground water samples, it is concluded in the report that the analytical results from the soil gas sampling indicate the presence of chlorinated solvents in ground water (Ref. 61, p. 15). Neve rtheless, the permanent ground water monitoring well EPA

- MW -0 5, being situated between Building 515 and the VA Medical Center (and immediately upgradient from Building 7), and having always shown an absence of PCE contamination, eliminates Building 515 as a potential source of PCEHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 43 to the contaminated ground water documented immediately downgradient of the VA Medical Center Building 7 ( Figure 3, Refs. 23, pp. 1, 3, 4, 6, 31, 32, 35, 49, 50, 64

- 66; 26, pp. 1

- 7, 16, 17, 27, 58; 28, pp. 15, 25, 33, 35, 81). I n addition, if contaminated ground water from beneath Building 515 was present and has travelled as far as SLC Well #18 (whether under natural gradient or by being pulled into the well during pumping, or both), PCE should be detectable in the well on a mor e continuous basis. Rather, PCE has only been detected in the well after continued pumping, which ground water modeling has shown is due to the well pulling contamination cross

- gradient from the site (Refs. 25, pp. 1

- 7; 29, pp. 20

- 22, 28, 33).

The UST Br anch of the UDEQ has a number of records concerning releases from various USTs on other parts of the Fort Douglas facility (Ref. 34, pp. 1

- 8, 35). The records indicate the closure of a number of tanks containing gasoline, diesel, heating oil or kerosene, a nd waste oil and that releases of gasoline, diesel and waste oil had occurred (Ref. 34, pp. 3, 6, 7). No record of any of the tanks holding PCE or solvents were located in UDEQ records. Following various clean up and removal actions for the releases, the UDEQ issued letters determining that no further action was needed at each release site in 1992, 1994, and 2002 (Ref. 34, pp.1, 2, 5, 8).

In addition to the dry

- cleaning facility, t he VA Medical Center has also maintained a clinical laboratory, boiler plant building, and a plant maintenance building that reportedly use solvents in small quantities to support regular operations (Ref . 8
, pp

. 2- 3). It has been reported that the clinical laboratory used xylene for tissue processing and, as of 2005, recycled approximately 1 gallon of xylene per month (Ref. 8, p. 2). As of 2005, the Maintenance and Operations staff stored approximately 30 ga llons of various solvents. Most solvent was recycled, and if any was unable to be recycled it was disposed of as hazardous waste (Ref. 8, p. 2). These other potential sources of PCE contamination located on the VA Medical Center have been eliminated as v iable sources for the PCE contamination due to the reported small quantities of solvent used (particularly in comparison to the quantity of PCE stored for the dry

- cleaning operation), the apparent high recycle and appropriate disposal rates, and that, give n there were a variety of solvents used, that PCE (if used at all) likely only made up a smaller overall proportion of this small quantity. Other activities associated with the VA Medical Center (Map ID # 19) (Refs. 6, pp. 59, 60; 8, pp. 2

- 3; 34, pp. 9- 11, 35).

The Underground Storage Tank (UST) Branch of the UDEQ has records concerning the closure of six USTs from VA Medica l Center Building 6 (located west and adjacent to Building 7) in 1993 (Ref. 34, pp. 9

- 11, 35). The USTs held fuel oil, diesel and gasoline (Ref. 34, p. 11). No record of the tanks having held PCE or other solvents were located in UDEQ records. Soil contaminated with diesel

- range total petroleum hydrocarbons was noted during the removal and approximately 57 tons of soil were removed as part of the UST closure (Ref. 34, p. 10). On November 7, 1994, the UDEQ issued a letter to the VA Medical Center recommending that no further action was required at the release site (Ref. 34, p. 9).

Businesses or facilities located downgradient of Building 7 and the sewer line, but proximate to the area of highest concentrations of PCE in ground water

The Toeroek research also identified six businesses or facilities located downgradient of Building 7 and the sewer line, but proximate to the area of highest concentrations of PCE in ground water (Map ID #’s 1, 2, 3, 16, 17, 18 ) (Ref. 6, pp. 5, 30

- 32, 39, 43 , 59

- 60 ). Given th eir location downgradient of the source area of the site (and the contamination noted in monitoring well EPA

- MW

- 02), none of these businesses or facilities is considered to be the primary source of contamination at the site. However, given their location proximate to the area of highest PCE concentrations in ground water found at the site, further discussion of these businesses or facilities is warranted (Ref. 6, pp. 59, 60 ).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 44 As note d above, Map ID #1 is the site itself, as identified by a previous name (the ‘ Mount Olive t Cemetary [ sic ] Plume’) within CERLCIS ( Ref. 6, pp. 5, 59, 60 ). Mount Olive t Cemetary [ sic ] Plume ( Map ID #1, Ref. 6, pp. 5, 59, 60 ).

Map ID #2 is the United States Department of Agriculture (USDA) Forest Service, Interagency Fire Center

. This was a heliport and vehicle fueling facility run by the Forest Service (Ref s . 6, pp. 5 , 39, 43, 59, 60 ; 34 , pp. 20

- 23). The Forest Service operated three USTs at the site, two containing gasoline and one containing aviation gasoline (Refs. 6, pp. 5, 39, 43, 59, 60; 34, pp. 20

- 23). All three tanks were closed in the early 1990’s (Ref. 34, pp. 20

- 23). While n o correspondence between UDEQ a nd the Forest Service regarding further action at the site was found, given the contents of the tanks (petroleum products, not solvents), it is not considered that this facility is a likely contributor to the PCE contaminatio n in ground water. According to Toeroek, no information suggesting that activities such as heavy machinery repair or engine rebuilding occurred at the facility was found (Ref. 6, pp. 39, 43). United States Department of Agriculture (USDA) Forest Service, Interagency Fire Center (M ap ID #2, Refs. 6, pp. 5, 39, 43; 34, pp. 20

- 23)

.

The Organizational Maintenance Shop 5 (OMS

- 5) Motor Pool (Map ID# 3) and Combined Support Maintenance Shop (CSMS) were both situated on Utah Army National Guard property located along Guardsman Way ( Ref. 6, pp. 59, 60 ). The address for OMS

- 5 has been variously recorded as 720 Guardsman Way
, 780 Guardsman Way and 1543 Sunnyside Avenue (Refs. 6, pp. 5, 32; 34, p. 15) and t he address for the CSMS is recorded as 580 Guardsman Way (Ref. 6

, p. 39 ) . These shops were initially considered the likely source of the PCE contamination first discovered in the Mount Olivet irrigation well (Refs. 18, p. 4; 19, p. 4). While various so lvents were used at the shops , including Stoddard’s solvent ( which according to the UANG did not contain PCE ) and Safety Kleen 105 ( which could have contained up to 0.5% PCE (Ref. 35, p p . 8, 12) )

, subsequent investigation determined that PCE

- contaminated ground water was also located upgradient of the UANG property (in the direction of t he VA Medical Center) (Refs. 20 ; 23). Utah Army National Guard (UANG) ( Map ID s #3 and #18 , Refs. 6, pp. 5 , 8, 32, 39, 43 , 49 , 59, 60 ; 19, p. 4; 34, pp. 35)

.

Waste solvents at the UANG property were stored in tanks located on site (Ref. 35, pp. 8, 9, 12). According to the UANG, the Stoddard’s solvent was recycled by filtering and reuse (Ref. 35, p. 12). Beginning in the mid - to late 1980’s, the UANG enlisted the Safety Kleen Corporation to provide solvent recycling services (Ref. 35, pp. 8, 12).

The UST Branch of the UDEQ has a number of records concerning a diesel release from a UST at the OMS

- 5 shop (Ref. 34, pp. 1 5- 19). In 1992, following a removal action to excavate petroleum

- contaminated soil, the UDEQ issued a letter determining that no further action at the release site was needed (Ref. 34, p. 15).

Given that waste solvent used on the UANG property was appare ntly stored in tanks and recycled either on (prior to 1984) or off site, as opposed to being disposed of into the sanitary sewer as has been documented at the VA Medical Center, and that PCE

- contaminated ground water has been identified upgradient of the
p roperty , the UANG shops are not considered the primary source of the PCE contamination documented at the site.

Toeroek identified an historic ‘carpet and furniture cleaner’ facili ty (Map ID #16) at 923 Greenwood Terrace, approximately 1⁄2 mile southwest of Building 7 (Ref. 6, pp. 8, 41, 48, 59, 60). Toeroek did not specify whether or not dry cleaning with PCE occurred at the location. This address is outside of the known extent of ground water contamination and is approximately 1,000 feet downgradient, and 1,600 feet cross

- gradient from the Carpet and Furniture Cleaner (Map ID# 16) (Ref. 6, pp. 8, 41, 48, 59, 60).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 45 contamination noted in monitoring well EPA

- MW

- 02 (Ref. 6, p. 60). Given its location, it is not considered likely that this facility is the pr imary source of the PCE contamination documented at the site.

Map ID # 17 has been identified as a mistaken listing within the CERCLIS database. According to Toeroek, this site was used as a place to dump grass cuttings, trees, and shrubs from the nearby cemetery (Mount Olivet). Old Dump/ Fill at 800 S Sunnyside Avenue (Map ID #17) (Ref. 6, pp. 8, 39, 49, 59, 60).

The Sugar House Park Plume (UT0000987776) is a separate area of ground water contami nated with PCE that has been identified within the TDL of site (Ref. 36). Discovered in the late 1980’s, the Sugar House Park Plume is located in a mixed commercial and residential area approximately 2.25 miles south of the 700 South 1600 East PCE Plume site, at an elevation of approximately 4,430 feet amsl (Ref. 36, pp. 6, 9). As of 2009, the source of the contamination had not been identified (Ref. 36, p. 5). Ground water flow direction in the area of the Sugar House Park site is towards the west

- south west (Ref. 36, pp. 8, 9). As this site is cross

- gradient from the contamination at the 700 South 1600 East PCE Plume, and the Sugar House Park site is located over 200 feet lower in elevation than the 700 South 1600 East site, it is considered that the PC E contamination at the two sites is not related (Ref. 36, pp. 6, 8, 9). Other PCE ground water contamination within in the TDL

3.2 WASTE CHARACTERISTICS (Ref. 1, p. 51601 )

3.2.1 TOXICITY/MOBILITY (Ref. 1, p. 51601 )

TABLE 11 : Ground Water Toxicity/Mobility

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

- 9) References

PCE 1 100 1 Yes 100 2, p

. 2

Toxicity/Mobility Factor Value: 100 ( Ref. 1, Section 3.2.1.3)HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 46 3.2.2 HAZARDOUS WASTE QUANTITY (Ref. 1, p. 51602)

TABLE 12 : Hazardous Waste Quantity

Source Source T ype Source Hazardous Waste Quantity ( Ref. 1, Section 2.4.2.1. 2) Disposal of PCE to sewer Other Undetermined, but greater than zero

The hazardous constituent quantity for t he source has not been adequately determined. The hazardous waste quantity is undetermined, but greater than zero. According to Section 2.4.2.2 of the HRS (Ref. 1, p. 51592), if any target for the migration pathway under consideration is subject to Level I (or Level II) concentrations, assign either the value from Table 2

- 6 (Ref. 1 , p. 51591 ) or a value of 100, whichever is greater, as the hazardous waste quantity factor value for that pathway. Because Level I I concentrations are present in a drinki ng water well at the site, a hazardous waste quantity factor value of 100 is assigned.

Hazardous Waste Quantity Factor Value: 100 (Ref. 1, Table 2 -6 , p. 51591 )

3.2.3 WASTE CHARACTERISTICS FACTOR CATEGORY VALUE ( Ref. 1, p p

. 51592, 51602 )

Toxicity/Mo bility Factor Value: 100 Hazardous Waste Quantity Factor Value: 100

Toxicity/Mobility Factor Value X Hazardous Waste Quantity Factor Value: 10,000

Waste Characteristics Factor Category Value: 1 0 (Ref. 1, Table 2 -7 , p. 51592 )

3.3 TARGETS (Ref. 1, p. 51602 )

The municipal water supply system in Salt Lake City is one of the most complex in the world (Ref. 49, p. 1 )

. According to UDEQ Division of Drinking Water (UDDW) records, there are 30 active community water systems in Salt Lake County, servin g system populations that range from 50 to 915,500 persons through the use of 185 active drinking water points of diversion (wells, springs, surface water intakes, and water purchased from other systems) (Ref. 5 2 , p p

. 2-5 ). This number does not include in active systems

, or systems serving non

community or non

- transient populations such as school, churches, or industries . N or does it include individual wells and springs that serve individual residen ces

. The Utah Division of Water Rights (UDWR) database,

w hich contains both drinking and non

- drinking water sources, has records for nearly 1,500 domestic and municipal wells within 4 miles of the site (Ref. 52, p. 6 ).

According to the most c urrent records from the UD DW , t here are six municipal water systems t hat have wells within the 4

- mile radius TDL (as measured from the source area at the VA Medical Center) (Ref. 52, p p . 7, 8 ). Of these six systems, four serve less than 60 people, are considered ‘inactive’, do not have water use records in the UDWR database , and/or are not located with in the primary aquifer (Ref. 52, p. 8)

. One of these ‘inactive’ water systems, the ‘Eighth South Well’

, is an artesian well that supplies a public drinking fountain; a transient source that is not used for scoring purposes (Re f. 52, p . 8)

. Given the lack of water use data, that the wells from these four systems would only be scored on potential contamination and would not contribute significantly to the overall site score, these four water systems will not be considered furthe r.HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 47 The two remaining municipal water systems that have wells within the TDL are the Salt Lake City Water System (SLCWS) and the South Salt Lake City Water System (S

- SLCWS ). The SLCWS is the water utility within the Salt Lake City Department of Public Utilities (SLCDPU) and currently serves approximately 400,000 persons (Refs. 46; 49, p. 1; 52, p p

. 4, 8, 10, 11 ). SLCWS Well #18 belongs to the SLCWS and is the only well subject to actual contamination (Level II) (Refs. 29, p. 1; 46). The S

- SLCWS currently serves approximately 18,000 persons (through approximately 3,300 connections (Ref s

. 52, pp. 5, 8, 68; 53, p. 2 )

. The SLCWS utilizes approximately 42 different sources, although the input from each source into the water system can vary greatly by year o r season, with surface water intakes generally providing more water during spring runoff and wells contributing more to the systems during the summer months ( e.g. Ref. 52 , pp. 15, 28, 37 ). No one source supplies greater than 40% of the municipal supply in any typical year and water in the system is blended (Refs. 46; 49, p. 1; 50, pp. 3, 4; 52, pp. 10, 11, 68 ). The S

- SLCWS is much simpler, with produced water being supplied by three wells, and purchased water being acquired from one source (Refs. 52,
pp. 5, 67

- 82; 53, p. 2) . All of the water supplied by the three wells along with the purchased water is blended during distribution (Ref. 63, p. 1)

. As some governmental records are unavailable or incomplete , particularly for the S

- SLCWS , a variety of referen ces, including data from the UDWR, the UDDW, the City of South Salt Lake, and the Salt Lake City Department of Public Utilities, have been used to produce a best estimate of the population served by target wells for the principal aquifer. The latest fiscal year that well production data is available for the Salt Lake City Water System is 2011, and for the South Salt Lake City Water System is 2010 (Ref. 52).

Salt Lake City Water System ( SL CWS)

The SLCWS currently serves approximately 400,000 persons (Refs. 49, p. 1; 52, p. 4, 8, 10, 11 ). The figure presented by the UDDW, 387,506 persons

, will be used as it is the minimum number (Ref. 52, pp. 4, 8, 10, 11 ). For HRS scoring purposes, the population served by the SLCWS in 2004 must be identified in order to d etermine the Level II population value for SLCWS Well #18, which was shut down due to site related PCE contamination in October 2004 (Refs. 23, pp. 6, 47, 64; 29, p. 41; 40, p. 9; 46; 52, p. 42 ). However, the most
current available population data will be used in order to score the remaining wells subject to potential contamination.

According to records from the UD DW, in 2004, the SLCWS sourced water from three surface water intakes on Wasatch Front creeks (Big Cottonwood Creek, P arleys Creek

, and City Creek), approximately 20 deep ground water wells, at least four springs

, and from the Metropolitan Water District, which at that time received all of its water from the Deer Creek Reservoir on the Provo River (Ref s . 50, p. 2 ; 52, pp. 10

- 66 ). [Note that Reference 52 pages 2-5 show system facilities (wells, springs, intakes) for water systems in Salt Lake County and does not include system facilities located outside the County. Reference 52, pages 10 and 11 show all system facilities, regardless of the ir location]. According to the SLCDPU, t he approximate breakdown of water supply sources for the SLCWS in 2004 was: surface wa ter intakes on Wasatch Front creeks = 51% ; base wells (i.e. flowing artesian wells) and springs = 8.8%; peakin g well (standby wells pumped on an as

- needed basis, usually in the summer (e.g. SLCWS Well #18) = 12.7%; and water sourced from the Metropolitan Water District (i.e. the Deer Creek Reservoir) = 27.5% (Ref. 50, p. 3). Actual contamination well

Similar percentages are found for dif ferent years in other references (Refs. 49, p. 1; 55, p. 2 ). Although the input from each source into the system can vary greatly by year or season, in a typical year, no one source supplies greater than 40% of the municipal supply in any one year (Refs. 46; 49, p. 1; 50, p p . 3, 4; 52, pp. 10

- 66 ). It should be noted however, that in fiscal year 2011, the Big Cottonwood Creek intake supplie dHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 48 approximately 42,517.6 acre feet or 46% of the total water in the SLCWS (Ref. 5 2 , p p

. 10, 11, 15 ). However, accordi ng to records collected since 1979, this source typically supplies an average of less than 24,000 acre feet (Ref. 52 , p. 15 ). Given this anomalous contribution ( e.g. its contribution for calendar year 2011 was approximately 33% of that for calendar year 2 010), and the fact that the HRS specifies to use the “average annual pumpage or capacity,” for HRS scoring purposes this source is not considered to supply > 40% (Refs. 1, p. 5 1603; 52 , p. 15)

. Specific data on the number of persons served in 2004 could not be found, but would be expected to be only slightly lower than the 2010 data presented in References 49 and 52 , as the population of Salt Lake City only increased 1.9% from 2000 to 2010 (Ref. 54, p. 2). To reflect a minimum possible number, the estimate d population served by the system in 2000 (using the UDDW data) will be used for the 2004 estimated population served: [ 387,506 persons - (387,506 persons x 0.019)] = 380,143 persons served ) ] (Refs. 52, pp. 4, 8, 10, 11; 54, p. 2)

.

Available records from the UDWR for 2004 are not complete, but show a similar breakdown of source supply as in 2010 : surface water intakes on Wasatch Front creeks = 59.6%; wells = 12%; springs = 4.6%; and water sourced from the Metropolitan Water District (i.e. the Deer Creek Re servoir) = 23.9% (Ref s

. 50, p. 3; 52, p p

. 8, 10 , 13 )

. No one source supplied greater than 40% of all water in the SLCWS in 2004 (Refs. 46; 52, pp. 10, 11 ). The largest source was Parley’s intake, which supplied 31.3 % (Ref. 52, pp. 10, 11, 18, 19 ).

In 2 004, there were approximately 42 individual sources of drinking water in the SLCWS listed as ‘active’ (Ref. 52, pp. 10, 11 ). The actual number of actively contributing source of water is likely lower than this, as source use records are missing or not complete for some of these sources, and at least a few appear to be abandoned (Ref. 52, pp. 10

- 66 ). The input from each source into the system can vary greatly by year or
season, although no one source supplied greater than 40% of the municipal supply in 200 4 (Refs. 46; 49, p. 1; 50, pp. 3, 4; 52, pp. 15, 28, 37 ). In order to reflect the minimum possible number, it will be assumed that all 42 individual sources are active each year , including in 2004

. As no one source supplie d greater than 40% of the supply in 2004 to the SLCWS and the sources were blended (Refs. 46; 52, pp. 10, 11 ), according to Section 3.3.2 of the HRS, it is assumed that each source in the water system contributes equally to the system and population served by the system is apportioned eq ually among the

sources (Ref. 1, p. 51603). The estimated popu lation served by SLCWS in 2004 wa s 380,143 (Refs. 52, pp . 4, 8, 10, 11 ; 54, p. 2). Therefore, the population served by SLCWS Well #18 in 2004 , and subject to actual (Level II) contamination was 9,051 persons (380,143 / 42 = 9,051 ).

Potential contamination wells

There are three SLCWS wells subject to potential contamination. Two of these wells

, the 4 th Avenue Well and the 13 th East Well

, were active in fiscal y ear 2011 (Ref. 52 , pp. 10, 11, 37 , 45). A third well, the 1900 East 2700 S Well, was not active in 2011 (Refs. 51; 52, pp. 7, 8, 10, 48 ). These wells are standby wells that are maintained on a regular basis (Refs. 1, p. 51603; 52, pp. 37

- 42, 45

- 50 ). These wells will be scored using

cur rent population numbers. All three wells are located within 2 to 3 mile target distance category of the 4

- Mile TDL.

In a typical year, no one source supplies greater than 40% of the municipal supply in any one year (Refs. 46; 49, p. 1; 50, pp. 3, 4; 52 , pp. 10

- 66). H owever, in fiscal year 2011, the Big Cottonwood Creek intake supplie d approximately 42,517.6 acre feet or 46% of the total water in the SLCWS (Ref. 52, pp. 10, 11, 15). However, according to records collected since 1979, this source typica lly supplies an average of less than 24,000 acre feet (Ref. 52 , p. 15). Given this anomalous contribution (e.g. its contribution for calendar year 2011 was approximately 33% of that for calendar year 2010), and the fact that the HRS specifies to use the “ averageHRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 49 annual pumpage or capacity,” for HRS scoring purposes this source is not considered to supply > 40% (Refs. 1, p. 51603; 52 , p. 15). The po pulation currently served by SLCWS i s 387,506 persons (Ref. 52, p. 4, 10, 11 ). In 2011, there were approxima tely 42 individual sources of drinking water in the SLCWS listed as ‘active’ (Ref. 52, pp. 10, 11). The actual number of actively contributing source of water is likely lower than this, as source use records are missing or not complete for some of these sources, and at least a few appear to be abandoned (Ref. 52, pp. 10

- 66). In order to estimate the minimum population, it will be assumed that all 42 individual sources are active each year, including in 2011. Therefore, the population served by each well is 9,226 (387,506 / 42 = 9,226 ).

South Salt Lake City Water System (S

- SL CWS)

The proportion of water produced and purchased by the City of South Salt Lake varies significantly year to year (Ref. 53, p. 2). For fiscal year 2010 (12 months ending June 30, 201 0, the latest complete fiscal year for which well production water is available from the UDWR) the S

- SLCWS supplied 958 million gallons of water (approximately 2,940 acre feet) to 3,323 service connections serving approximately 18,000 people (Refs. 52, p. 5, 67, 68 ; 53, pp. 2). Of this total, the City of South Salt Lake purchased 297 million gallons of water (31 percent (%) or 911.5 acre feet) of its water from the Jordan Valley Water Conservancy District and produced 661 million gallons (69 % or 2,028.5 a cre feet) of its own water (Ref. 53, p. 2). According to records from the UDWR, in fiscal year 2010 (the latest fiscal year for which S- SLCWS well production data from UDWR is available) the S

- SLCWS produced water from three wells: the 300 East Replaceme nt well (945.5 acre feet), the 700 East Replacement well (224.7 acre feet), and the Davis Replacement well (843.8 acre feet); totaling 2,014 acre feet (Ref. 52, pp. 5, 67, 68, 71, 75, 80, 81 )

. [ Note that Ref. 53 states a similar total of 2,028.5 acre feet of water was contributed from wells. The figure of 2,014 acre feet is used as it taken from UDWR records which are considered more accura te] . The Davis Replacement well is used year

- round, while the 300 East Replacement well and the 700 East Replacement well are currently both standby wells that are maintained on a regular basis (Refs. 1, p. 51603; 52, pp. 5, 67, 68, 71, 75, 80, 81 ).

The Jordan Valley Water Conservancy District sources the majority of its water from numerous surface water sources, includi ng the Provo River and its tributaries, several mountain lakes, and two reservoirs (Ref. 62, p. 1). The majority of this water is treated at the Jordan Valley Water Treatment Plant (i.e. blended), which then supplies 90% of all water delivered by the JVWCD (Ref. 62, p. 1).

As the water purchased by the S

- SLCWS from the JVWCD can be considered as coming from one source ( a single main ), the contribution of each S

- SLCWS source to the system is therefore: water purchased from the Jorda n Valley Water Treatment Plant = 31.0%, 300 East Replacement Well = 32.2%, 700 East Replacement Well = 7.6% and the Davis Replacement Well = 28.7% (Ref. 52, pp. 5, 67, 68, 71, 75, 80, 81 ; Ref. 63). All water produced by the three wells and purchased from the JVWCD is blended dur ing distribution (Ref. 63, p. 1). As no one source supplies greater than 40% of the supply in any one year to the S

- SLCWS, according to Section 3.3.2 of the HRS, it is assumed that each source contributes equally to the system and population served by each source is apportioned equally (Ref. 1, p. 51603).

Only the S- SLCWS 300 East Replacement Well falls within the TDL

, lying within the 3

- 4 mile target distance category (Refs. 51; 52, pp. 11, 12, 16 ). This well will be scored on potential contamination usin g current population estimates . As the population of 18,000 served by the S

- SLCWS is to be apportioned equally between all four sources, this well is considered to supply water to approximately 4,500 persons (18,000 / 4 = 4,500) (Ref. 1, p. 51603).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 50 TABLE 13 : Municipal Drinking Water Wells in the Principal Aquifer within a 4

- Mile Radius of th e VA Medical Center Dry Cleaner

Well ID Perforated Interval ( feet amsl) Distance From Source Level I Cont. (Y/N) Level II Cont. (Y/N) Pot. Cont. (Y/N) Population Served References

SLCWS Well #18 (aka 15 th East Well

or 500 South Well) 4,448 – 4,204 1/4

- 1/2 mile N Y (Level II) N 9,051 29, pp. 24 ; 51; 40, pp. 1, 9; 52, pp. 10,

11, 40

- 42

SLCWS 4 th Ave Well 4,272 – 4,014 2- 3 miles N N Y 9,226 51; 52, pp . 4, 10, 11, 37

- 39

SLCWS 13 th East Well 4,249 – 3,919 2- 3 miles N N Y 9,226 51; 52, pp. 10, 11, 45

- 47

SLCWS 1900 E

2700 S Well 4,193 – 3,984 (Est.) 2- 3 miles N N Y 9,226 51; 52, pp. 10, 11, 48

- 50

S

- SLCWS 300 E. Replacement Well 3,660 – 3,270 3- 4 miles N N Y 4,500 51 ; 52, pp. 68, 75

- 79

Notes: Est. Estimated (not recorded on drill log)

3.3.1 NEAREST WELL ( Ref. 1, p p . 51602, 51603 )

Concentra tions of PCE meeting the observed release criteria found in HRS Table 2 -3 have been detected in SLCWS Well #18 (Refs. 1, p. 51 603; 23, pp. 48, 64; 25, pp. 4, 5 ). The highest PCE concentration s recorded in this well have been less than 3 μg/L (Ref s. 23, p p

. 47, 48, 64 ; 29, p. 9 ). As this is below the applicable health

- based benchmark for drinking water (the MCL, which is 5.0 μg/ L) , this well is considered to be subject to Level I I concentrations (Ref. 1, p.51592) . In accordance with Table 3

- 10 and 3

- 11 within Section 3.3.1 of the HRS, a Nearest Well Factor Value of 45 has been assigned (Ref. 1, p. 51603)

.

Well ID: SLCWS Well #1 8 ( aka 15 th East Well or 500 South Well ) Level of Contamination (I, II, or potential): I I If potential contamination, distance from source in miles: Not applicable

Nearest Well Factor Value: 4 5 (Refs. 1, p. 51603 Table 3 -11 )HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 51 3.3.2 POPULATION (Ref . 1, p. 51603)

3.3.2.1 Level of Contamination (Ref. 1, p. 51603)

3.3.2.2 Level I Concentrations (Ref . 1, p. 51603 )

Not applicable as no Level I concentrations have been identified.

Total Population S erved by Level I Wells: NA

Level I Concentrati on s Factor Value: 0

3.3.2.3 Level II Concentrations (Ref. 1, p. 51603 )

Level I I concentrations have been identified in SLCWS Well #18 (Refs. 23, pp. 6, 48, 64; 25, pp. 4, 5). The principal aquifer is highly transmissive and when Well #18 is pumped, it has sufficient capacity to alter the ground water flow regime in the area and draw the PCE contamination into the well (Ref. 29, pp. 19

- 21, 27, 33 , 46

- 48 ). When the well was shut off seasonally, the ground water flow regime return ed to static conditions

a nd ground water resume d its normal flow direction (to the southwest)

. In addition, when pumping SLCWS Well #18, a strong water level response has been noted within EPA

- MW

1D, a well 1,600 feet away and nearer to t he source , indicating a hydraulic connection across this distance (Ref. 29, p. 30).

In October 2004, t his municipal well was shut down due to PCE contamination (Refs. 46; 52, pp. 12, 13, 26). The assigned population value for actual contamination of ground water targets at Level I I concentrati ons for the principal aquifer are presented in Table 14 below.

TABLE 14: Population Subject to Level II Concentrations

Level I I Well Distance Category Population Assigned Population Value References

SLCWS Well #18 Greater than 1/4 to 1/2 9,051 9,05 1 23, pp. 6, 48, 64; 25, pp. 4, 5 ; 29, pp. 19

- 21, 27, 33 , 46

- 48; 40, p . 1, 9; 52, pp. 10, 11

Level II Concentration s Factor Value: 9,051

3.3.2.4 Potential Contamination (Ref. 1, p. 51603 )

Distance

- weighted population values for potential contaminati on ground water targets for the principal aquifer are presented in Table 15.

Ground water moves laterally from the unconfined part of the principal aquifer near the mountains (i.e. at the source area of the site) towards the confined part of the aquifer in the valley center (west of the site), therefore the two parts of the principal aquifer are interconnected (Refs. 38, p. 7, 9, 10; 41, p. 4, 5; 42, p. 3). The principal aquifer is highly transmissive and is an important source of drinking water for Sal t Lake Valley,HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 52 contributing water to about 38% of the population (Refs. 29, pp. 19

- 21; 38, pp. 7, 8; 41, p. 7; 42, p. 3). The Wasatch Mountains located to the north and east of the site f orm a bedrock aquifer that is different from the interconnected unco nsolidated basin

- fill sediments present in the valley. The principal aquifer present to the south and west of the Wasatch Mountains is continuous within the 4

- mile radius of t he source (Refs. 38, p. 7, 9, 10; 41, p. 4, 5; 42, p. 3).

TABLE 15 : Distance -W eighted Population Values for Potential Contamination Factor

Distance Category Population Distance

- Weighted Population Value (Ref. 1, Table 3

- 12) Reference s

Greater than 0 to 1⁄4 mile 0 0 29, pp. 24; 51; 40, pp. 1, 9; 52, pp. 10, 11, 40

- 42

Greater than 1⁄4 to 1⁄2 mile 0 0 51

Greater than 1⁄2 to 1 mile 0 0 51

Greater than 1 to 2 miles 0 0 51

Greater than 2 to 3 miles 27,678 2,122 51; 52, pp . 4, 10, 11, 37

- 39, 45

- 50

Greater than 3 to 4 miles 4,500 417 51; 52, pp. 68, 75

- 79

Calculations ( Ref. 1, Section 3.3.2.4, pp. 51603, 51604):

Sum of Distance

- Weighted Population Values: 2,539 Sum of Distance

- Weighted Population Values/10: 2 53.9 , rounded to 2 54

Potential Contamination Factor Value: 2 54

3.3.3 RESOURCES (Ref. 1, p. 51604 )

It is not known if any well within the four

- mile radius is used for irrigation of commercial food or forage crops, or if any well may otherwise be considered a resource for scoring purposes.

Resources Factor Value: 0

3.3.4 WELLHEAD PROTECTION AREA (Ref. 1, p. 51604 )

Wellhead Protection Areas (WPAs) were identified for two wells (Refs. 1, p. 51604; 56; 57 ). The UDEQ Division of Drinking Water has required public water systems to establish Drinking Water Source Protection (DWSP) areas under Rule R309

- 600 (Re f. 56 , pp. 1, 2 ). Under this rule, DWSP plans were created for each ground water source of drinking water for each public water system in Salt Lake City (Ref. 56 , p . 2 ). As part of each DWSP plan, four zones were delineated for management purposes: zone 1 is a 100 foot radius of the wellhead, zone 2 is the area within a 250

- day ground water time

- of

- travel, zone 3 is the area within a 3

- year ground water time

- of

- travel, and zone 4 is the area within a 15

- year ground water time

- of

- travel (Ref. 56 , p. 4 ).HRS Documentation Record (Interim Final) 09/2012 700 South 1600 East PCE Plume UTD981548985 53 DWSP z one 4 for the “8 th South Well” (aka 8 th South artesian well) passes directly beneath t he source , which has a containment factor of 10 (Ref s. 52, pp. 68, 69; 57, pp. 1, 2). In addition, observed ground water PCE contamination has been detected withi n all four DWSP zones established for SLC WS Well #18 ( Refs. 23 , p. 48, 64; 25, pp. 2

- 5; 29, pp. 18, 20

- 22 ; 57, pp. 1, 2 ). The SLCWS Well #18 is completed in the principal aquifer (Ref . 52, pp . 40

- 42 ). As the 8 th South well is artesian and completed to a depth of 130 feet, it is likely also pulling water from the principal aquifer (Ref. 52, pp. 83

- 85).

As per Section 3.3.4 of the HRS, a Wellhead Protection Area Factor Value of 20 has been assign ed for the principal aquifer (Ref. 1, p. 51604)

.

Wellhead P rotection Area Factor Value: 20