HRS DOCUMENTATION RECORD

-- REVIEW COVER SHEET

Name of Site: Hormigas Ground Water Plume

CERCLIS ID No.: PRN000206359

Date Prepared: October 2010

Contact Persons

Site Investigations: Denise Zeno (212) 637

- 4319 U.S. Environmental Protection Agency New York, NY

Documentation Record: Ildefonso Acosta (212) 637

- 434 4 U.S. Environmental Protection Agency New York, NY

Pathways, Components, or Threats Not Scored

The surface water, soil exposure, and air pathways were not scored becaus e the listing decision is not significantly affected by those pathways. The site score is sufficient to list the site on the ground water pathway score.This page has been left blank intentionally.1 HRS DOCUMENTATION RECORD

Name of Site: Hormigas Groun d Water Plume

CERCLIS ID No.: PRN000206359 [Ref . 3 , p. 1]

EPA Region: 2 Date Prepared: October 2010

S treet Address of Site: * Carretera 785 Km 4.9 [Ref. 3, p. 1]

County
, State , and ZIP Code : Caguas, Puerto Rico 00 725 [Ref. 3, p. 1]

General Location i n the State: interior, east

- central Puerto Rico [Figure 1]

Topographic Map: Caguas, PR [Ref. 5, p. 1]

Latitude: * 18° 13' 14.16" ( 18.2206° ) North Longitude: * 66° 0 6' 3. 6" ( 66.1010 °) West

[Figure 1; Ref. 4, pp. 1

- 2; 5, p. 1]

The site consists of a ground water plume with no identified source(s) of contamination [Figure 1; Ref. 3, p. 1]

. The area of observed ground water contamination consists of the Eufracia well , a former public supply well that was closed after contaminants were detected, and the area around the well [Figure 1]

. The reference point for the street address and site latitude / longitude coordinates is the Eufracia well [ Figure 1; Ref

. 1, p. 51595; 4 , p p. 1-2]. The Eufracia well does not have a specific street address (i.e., no number) , but it is accessible from Carretera (i.e., Route) 785 and is located approximately 1,000 feet west of the road; t he street address listed here identifies the nearest kilometer marker to the well [ Figure 1; Ref. 11 , pp. 3, 14

- 15, 4 8 ].

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

Scores

Ground Water Pathway 100.00 Surf ace Water Pathway Not Scored Soil Exposure Pathway Not Scored Air Pathway Not Scored

HRS SITE SCORE 50.002 WORKSHEET FOR COMPUTING HRS SITE SCORE Hormigas Ground Water Plume

S S 2

1. Ground Water Migration Pathway Score (S gw ) 100.00 10,00 0 (from Table 3

- 1, line 13)

2a. Surface Water Overland/Flood Migration Component Not Scored (from Table 4

- 1, line 30)

2b. Ground Water to Surface Water Migration Component Not Scored (from Table 4

- 25, line 28)

2c. Surface Water Migration Pathway Score ( S sw ) Not Scored Enter the larger of lines 2a and 2b as the pathway score.

3. Soil Exposure Pathway Score (S s ) Not Scored (from Table 5

- 1, line 22)

4. Air Migration Pathway Score (S a ) Not Scored (from Table 6

- 1, line 12)

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 50.003 GROUND WATER MIGRATION PATHWAY SCORESHEET Hormigas Ground Water Plume

GROUND WATER MIGRATION PATHWAY Factor Categories & Factors MAXIMUM VAL UE VALUE ASSIGNED

Likelihood of Release 1. Observed Release 550 550 2. Potential to Release 2a. Containment 10 not scored 2b. Net Precipitation 10 not scored 2c. Depth to Aquifer 5 not scored 2d. Travel Time 35 not scored 2e. Potential to R elease [lines 2a(2b+2c+2d)] 500 not scored

3. Likelihood of Release 550 550

Waste Characteristics 4. Toxicity/Mobility * 10,000 5. Hazardous Waste Quantity * 100 6. Waste Characteristics 100 32

Targets 7. Nearest Well 50 50 8. Populati on 8a. Level I Concentrations ** 32
, 93 0 8b. Level II Concentrations ** 0 8c. Potential Contamination ** not scored 8d. Population (lines 8a+8b+8c) ** 32
, 93 0 9. Resources 5 5 10. Wellhead Protection Area 20 20 11. Targets (lines 7+8d+9+10) ** 33,00 5

12. Aquifer Score (lines 3x6x1 1 divided by 82,500) 100 100

13. Ground Water Migration Pathway Score (Sgw) 100 100.00

* Maximum value applies to waste characteristics category.

** Maximum value not applicable.4 REFERE NCES

Reference Number Description of the Reference

1. U.S. Environmental Protection Agency (EPA). Hazard Ranking System, Final Rule . Federal Register, Volume 55, No. 241 , pp. 51532

- 51667

. http://www.epa.gov/superfund/sites/npl/hrsres/index.htm#HRS Rule

. December 14, 1990. [13 8 pages]

2. EPA. Superfund Chemical Data Matrix, SCDM Data Version s : 1/27/2004 and 6/23/2006, (Trichloroethylene update), Appendices B

- I (Hazardous Substance Factor Values) and B

- II (Hazardous Substance Benchmarks); excerpts downloaded on April 1, 2010

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

. [ 10 pages]

3. EPA. S uperfund Site Information, Hormigas Ground w ater Plume , Caguas, Puerto Rico : Site Information and Actions

. Downloaded f rom http://c fpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0206359 on March 26, 2010. [2 page s]

4. Morales, Julissa
, Region 2 Site Assessment Team 2 (SAT 2)

. P roject Note to Hormigas Groundw ater Plume HRS Site File, Subject: L atitude and Longitude Determination

. Ma rch 25, 2010

. [2 pages]

5. U.S. Department of the Interior Geological Survey (USGS). Caguas Quadrangle, Puerto Rico, 7.5

- Minute Series (Topographic)

. 1982 . [1 page]

6. Gilliland, Gerry, Weston Solutions, Inc

. Project Note to Hormigas Ground Water Plume si te file, Subject: Water Quality Reports – Hormigas Water System . April 2, 2010. [32 pages]

7. EPA. Envirofacts Warehouse, Safe Drinking Water Information System (SDWIS), Query Results, Caguas, Puerto Rico . Downloaded from http://oaspub.epa.gov/enviro/sdw_query_v2.get_list?wsys_name=&fac_search=fac_beginning&fac_county =CAGUAS&pop_serv=500&pop_serv=3300&pop_serv=10000&pop_serv=100000&pop_serv=100001&s ys_status=&pop_serv=&wsys_id=&fac_state=PR&last_fac_name=&page=1&query_ results=&total_rows_ found= on March 29 , 2010. [ 3 pages]

8. Gilliland, Gerry, Weston Solutions, Inc

. Project Note to Hormigas Ground Water Plume site file, Subject: Existing PRASA Analytical Data – Pozo Eufracia . March 31, 2010. [15 pages]

9. EPA. Envir ofacts Warehouse, SDWIS Violation Report, Hormigas I . Downloaded from http://oaspub.epa.gov/enviro/sdw_report_v2.first_table?pws_id=PR0005426&state=PR&source=Groundw ater&population=5488&sys_num=0 on April 2, 2010. [3 pages]

10. Blanco, Emma M., Puerto Rico Aqueduct and Sewer Authority (PRASA). Letter to Javier O. Torres, Puerto Rico Department of Health (PRDOH), RE: C losing Hormigas System, PWSID PR0005426

. February 17, 2009. [5 pages]

11. Weston Solutions, Inc

. Field Logbook with Photo Documentation, Hormigas Site Discovery, 20113.111.002.0123.00, DCN: SAT2.123.001 . August

- December 2009. [ 91 pages]

12. Morales, Julissa
, Weston Solutions, Inc

. Sampling Trip Report, Work Assignment No. 0123, Hormigas Site Discovery, Document Control No. SAT2.20113.123.876 . September 11, 2009. [23 pages]5 REFERENCES (continued)

Reference Number Description of the Reference

13. EPA Region 2 Laboratory. Approval Form/Project Checklist and Associated File Documents/VOC Data, Project Number : 090 9 000 1 , Project/Survey Name: Hormigas Site Discovery

. September 14

- 18 , 2009. [ 659 p ages]

14. Weston Solutions, Inc

. Field Logbook with Photo Documentation, 20405.012.013.0930.00, Hormigas Ground w ater Plume HRS Sampling, DCN: 930

- 4E

- AGGO . February

- March 2010. [49 pages]

15. Morales, Julissa, Weston Solutions, Inc

. Revised Sampling Trip Report, Work Assignment No. 20405.012.013.0930. 00, Hormigas HRS, Document Control No. 930

- 2A

- AGMH . April 1, 2010. [31 pages]

16. EPA Region 2 Hazardous Waste Support Section (HWSS)/Regional Sample Control Center (RSCC). Record of Communication (ROC) #1 and Data Transfer Log with attached Organic Data P ackage, Subject: CLP Data Package for Quality Assurance Review, Site: Hormigas Ground w ater Plume, Case #: 3 9528
, SDG #: B5QH0, B5QB9 . March 4

- 18, 2010. [ 66 pages]

17. EPA Region 2 HWSS/RSCC. ROC # 2 and Data Transfer Log with attached Organic Data Package, Subject: CLP Data Package for Quality Assurance Review, Site: Hormigas Ground w ater Plume, Case #: 3 9528 , SDG #: B5 Q B1 , B5Q A3 . March 5- 18, 2010. [ 10 6 pages]

18. Munch, J.W., ed., EPA National Exposure Research Laboratory. Method 524.2, Measurement of Purgea ble Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry, Revision 4.1 . EPA Office of Research and Development. 1995. [48 pages]

19. EPA. SOM01.2 Volatile T arget Compound List and Co rresponding CRQL s . Downloaded from http://www.epa.gov/superfund/programs/clp/som

- vtarget.htm on April 6, 2010 . [ 2 pages]

20. Veve, Thalia D. and Bruce E. Taggart (editors) , USGS. Atlas of Ground

- Water Resources in Puerto Ric o and the U.S. Virgin Islands, Section 2.5.1: Aguas Buenas

- Juncos Region by Juan C. Puig (pp. 106

- 112)

. Water Resources Investigations Report 94

- 4198. Prepared in cooperation with EPA. 1996. [ 2 0 pages]

21. Rodríguez, José M., USGS

. Assessment of Ground -W ater Withdrawals at Municipal Industrial Parks in Puerto Rico, 2000; excerpts . Scientific Investigation Report 2004

- 5029. Prepared in cooperation with Puerto Rico Industrial Development Company (PRIDCO). 2004. [ 18 pages]

22. Renken, Robert A. et al, USGS. Geology and Hydrogeology of the Caribbean Islands Aquifer System of the Commonwealth of Puerto Rico and the U.S. Virgin Islands . USGS Professional Paper 1419. 2002. Excerpt. [ 20 pages]

23. Gilliland, Gerry, Weston Solutions, Inc

. Project Note to Hormigas Ground Water Plume site file, Subject: Wells in the Project Study Area – Hormigas Ground Water Plume

. July 22 , 2010. [ 5 pages]

24. Molina

- Rivera, Wanda L., USGS. Estimated Water Use in Puerto Rico, 2000 . Open

- File Report 2005

- 1201. Prepared in cooperati on with PRASA, Puerto Rico Department of Natural and Environmental Resources (PRDNER), and Puerto Rico Environmental Quality Board (PREQB). 2005. [35 pages]

25. Puerto Rico Environmental Quality Board (PREQB). Final Wellhead Protection Program . April 1991

. [158 pages]6 REFERENCES (continued)

Reference Number Description of the Reference

26. EPA. Region 2 Water, Wellhead Protection Program . From http://www.epa.gov/region02/water/whp.htm

. Web Page last updated on August 28, 2009; Accessed and printed on April 6, 2010. [1 page]

27. Agency for Toxic Substances & Disease Registry (ATSDR). ATSDR T oxFAQs
, T etra chloroethylene
, CAS # 127

- 18 -4 . U.S. Department of Health and Human Services. September 1997. [2 pages]

28. ATSDR. ATSDR T oxFAQs
, Trichloroethylene , CAS # 79

- 01 -6

. U.S. Department of Health and Human Services. July 2003 . [ 2 pages]

29. ATSDR. ATSDR T oxFAQs , 1,2 -D ichloroethene , CAS # 540

- 59

- 0, 156

- 59

- 2, and 156

- 60 -5 . U.S. Department of Health and Human Services. September 1997. [2 pages]

30. Interstate Technology & Regulatory Cooperation (ITRC) Work Group In Situ Bioremediation Work Team and Industrial Members of the Remediation Technologies Development Forum (RTDF)

. Technical/Regulatory Guidelines, Natural Attenuation of Chlorinated Solvents in Ground w ater: Principles and Practices; appendices not included . September 1999. [32 pages]

31. Casta Velez, Alfredo, Puerto Rico Department of Health (PRDOH). Letter to Rafael L. Lama, PRASA, Re: Notice of Vi olation 004

- 06, Well Eufracia – Hormigas System (PR0005426), Violation for PCE; with attached translation by Weston Solutions, Inc . October 31, 2006. [5 pages]

32. EPA Region 2 Laboratory

. SOP# DW

- 1, Revision# 2.1, Analysis of Volatile Organic Compounds in Drinking Water by Purge and Trap GC/MS . February 13, 2009. [28 pages]

33. EPA Contract Laboratory Program (CLP). Modifications Updating SOM01.1 to SOM01.2; with attached excerpts from SOM01.1 . April 11, 2007. [117 pages]

34. Morales, Julissa, Weston Soluti ons, Inc, Region 2 SAT 2. Pre

- CERCLIS Screening Report, Hormigas Site Discovery, Caguas, Puerto Rico . Prepared for EPA. February 2010. [97 pages]

35. Albatross. Material Safety Data Sheet, Albatross Superkleen S.P.I.F. April 1, 2004. [6 pages]

36. Gomez -G omez, Fernando et al, USGS. Surface

- Water, Water

- Quality, and Ground

- Water Assessment of the Municipio of Caguas, Puerto Rico, 1997

- 99; excerpts . Water

- Resources Investigations Report 00

- 4280. Prepared in cooperation with the Municipio Autonomo de Caguas. 2001. [17 pages]

37. Environmental Data Resources, Inc. (EDR). The EDR Radius MapTM Report with GeoCheck®, Hormigas Site Discovery, State Road 785 Km 4.9 Interior, Caguas, PR 00703 , Inquiry Number: 2 600220 .2s

. September 28 , 2009. [47 p ages]SS – Site Summa ry

7 SITE SUMMARY

The Hormigas Ground Water Plume site (CERCLIS ID No. PRN000206359 ) consists of a ground water plume with no identified source(s) of contamination
, located in the municipality of Caguas, Puerto Rico [ Figure 1; Ref

. 3 , p. 1 ]. The geographic coordinates of the site are 18  ̊ 13 ' 14.16 " north latitude and 6 6  ̊ 06 ' 03. 60 " west longitude , based on the location of former public supply well Eufracia [ Figure 1; Ref

. 4 , pp. 1-2 ; 5 , p. 1].

The former Hormigas public water system (PWSID 5426) consist ed of two wells ( Eufracia and Hormigas) and served a population of 5,488 people ; according to the system’s operator, Puerto Rico Aqueduct and Sewer Authority (PRASA), the re were no other wells or surface water intakes contributing to the Hormigas system [Ref. 6 , p p . 1, 3- 4, 9, 15, 22, 31; 7, p. 2 ]

. The results for a sample collected f rom the Eufracia well in August 2006 by PRASA i ndicated the presence of tetrachloroethylene (PCE) at a concentration of 29 micrograms per liter (μg/L ; PRASA reported results in milligrams per liter [mg/L], which EPA has converted to μg/L for consistency wi th the EPA data) [Ref. 8, pp. 1, 4 ]. Puerto Rico Department of Health (PRDOH) responded to this analytical result by issuing PRASA a Notice of Violation (NOV) for noncompliance in October 2006 , explaining that the annual average PCE concentration of 7 μg/ L exceeded the Maximum Contaminant Level (MCL) of 5 μg/L [Ref. 31, pp. 1

- 5]. EPA’s Safe Drinking Water Information System (SDWIS) report ed that the Hormigas water s ystem had a health

- based violation for PCE d uring th e reporting period July

- September 2006 and that NOVs were issued, as well as an Administrative Order in February 2008 [Ref. 9, p. 1 ]

. PRASA closed the Hormigas water system and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in place [Ref. 7, p. 2; 10 , p. 1 ; 11, pp . 15
, 48, 54

- 56 ; 12, pp. 3 -4].

U.S. Environmental Protection Agency (EPA) collected two ground water samples from the Eufracia well in September 2009, and the results confirmed the presence of PCE, this time at concentrations of 260

- 280 μg/L [Ref. 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 1 6- 18
, 20- 22 ] . Trichloroethylene (TCE) and cis

- 1,2

- dichloroethylene (cis

- 1,2

- DCE) were also detected in the samples, at concentrations of 59

- 60 μg/L and 49

- 50 μg/L , respectively [Ref. 13, pp. 16 -1 8, 20

- 22 ]. The PCE and TCE concentrations detected in the Eufracia well significantly exceed the shared MCL of 5 μg/L [Ref. 2 , pp. 7, 10 ]. Samples collected from background wells showed non

- detects for PCE, TCE, and cis

- 1,2

- DCE [Ref. 11 , pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17 ; 13, pp. 5
, 8-9
, 12 , 2 5 , 2 8
, 31

- 32 ].

In December 2009, EPA conducted a reconnaissance effort in the vicinity of the Hormigas and Eufracia wells as part of a Site Discovery Initiative to identify possible sources of contamination [ Ref . 11, pp. 24

- 39, 60

- 91 ]. In February 2010, EPA collected soil samples from seven facilities identified as possible sources [Ref. 14, pp. 3

- 49; 15, pp. 3- 27]

. PCE was detected at just one location (Narvaez Cleaners) [Ref. 15 , pp. 3, 5, 16, 2 1; 16, pp. 17, 20]. PCE was not detected in soil samples collected at other possible source locations, including facilities that are located between the contaminated sample and the Eufracia well [Ref. 15

- 17, all pages]. In addition, the Narvaez facility is located closer to six community supply wells where PCE was not detected (400

- 3,000 feet) than it is to the Eufracia well (4,400 feet) [Figure 1; Ref. 11, pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8

- 9, 12, 25, 28, 31

- 32]. Two of the uncontaminated community s upply wells are located north of the Narvaez facility, as is the Eufracia well [Figure 1]. It should be noted that the general direction of ground water flow from the site vicinity is east

- northeast [Ref. 20, p. 1 9 ]. During the site discovery efforts, E PA did not observe or identify any possible source facilities located hydraulically upgradient (i.e., west

- southwest ) of the Eufracia well [Ref. 11, pp. 3

- 39; 34, pp. 5

- 6, 11

- 16, 21]. Based on these considerations, the re is not sufficient evidence (i.e., data for intervening areas) to attribute the ground water contamination in the Eufracia well specifically to sources at the Narvaez facility or any of the other facilities investigated during EPA’s Site Discovery Initiative and sampling event; therefore, t here is no identified source(s) of contamination.!<!<!<!<!<!<!<!<!<!C!C!C!C!C!C!CJR Auto Body Collision & PaintLat: 18.2034 / Long: -66.1075Taller PototoLat: 18.2243 / Long: -66.0925Taller GonzalezLat: 18.2142 / Long: -66.0998Mariel T-ShirtsLat: 18.2088 / Long: -66.1137Narvaez CleanersLat: 18.2085 / Long: -66.1005Country Professional Dry CleanersLat: 18.2036 / Long: -66.1074San Lorenzo BuslineLat: 18.2129 / Long: -66.0992Villas De OroHM2-GW01/HM2-GW02 (Dup)Lat: 18.2154 / Long: -66.0984Pozo Hormigas*Inaccessible, no sample takenLat: 18.2177 / Long: -66.1000El ParaisoHM-GW05Lat: 18.2079 / Long: -66.1025Villa VigiaHM-GW04Lat: 18.2083 / Long: -66.0993Los VelazquezHM-GW06 / HM2-GW03Lat: 18.2121 / Long: -66.0869La Sierra Pozo #2HM-GW08Lat: 18.2065 / Long: -66.1078La Sierra Pozo #1HM-GW07Lat: 18.2050 / Long: -66.1084La Sierra Pozo #3HM-GW09Lat: 18.2131 / Long: -66.1025Pozo EufraciaHM-GW01 / HM-GW02 (Dup)Lat: 18.2206 / Long: -66.1010DATE:CLIENT NAME:PROJECT:LEGEND:TITLE:Hormigas Ground Water Plume HRSEnvironmental Protection AgencyHormigas Ground Water Plume HRSHormigas WardCaguas PRFigure 1 - Site Location MapJuly 2010"Puerto RicoSite LocationSCALE:1,00001,000500Feet

P:\SAT2\Hormigas_SDI\MXD\07755_HGPO_HRS_SiteLocationMap.mxdNOTE:1. Sampling, well, and possible source locations were recorded electronically using Global Positioning System (GPS) technologyin the field.SOURCE:1. USGS. 7.5 Minute Series Topographic Quadrangles: CAGUAS, PR. 1982.2. Weston Solutions, Inc., Region 2 Site Assessment Team 2. Site Logbook,DCN # SAT2.123.001. August - December, 2009.3. Weston Solutions, Inc. Site Logbook, Hormigas Ground Water Plume HRSSampling, DCN # 930-4E-AGGO. Feburary 2010.Villas De OroHM2-GWLat: 18.2154 / Long: -66.0984Well NameSample IDLatitude / LongitudeMariel T-ShirtsLat: 18.2088 / Long: -66.1137Latitude / LongitudePrivate Community Well LocationFormer Public Supply Well Location!<!<Possible Source(Preliminary Investigation Feb-2010)!CFacility Name9 SD

- Characterization and Containment Source No.: 1

SOURCE DESCRIPTION

2.2 SOURCE CHARACTERIZATION

Number of the source: 1

Source Type of the source: O ther

Name and description of the source: Hormigas Ground Water Plume

Source 1 is considered a contaminated ground water plume of unknown volume without an identified source. PRASA’s former Hormigas public water system (PWSID 5426) consisted of two wel ls (Eufracia and Hormigas) and served a population of 5,488 people [Ref. 6, pp. 1, 3- 4, 9, 15, 22, 31; 7, p. 2]. The results for a sample collected from the Eufracia well in August 2006 by PRASA indicated the presenc e of PCE at a concentration of 29 μg/L [Ref. 8, pp. 1, 4 ; 31, p. 1 ]. PRDOH responded to this analytical result by issuing PRASA an NOV for noncompliance in October 2006, explaining that the annual average PCE concentration of 7 μg/L exceeded the MCL of 5 μg/L [Ref. 31, pp. 1

- 5]. EPA’s SDWIS reported that the Hormigas water s ystem had a health

- based violation for PCE d uring th e reporting period July

- September 2006 and that NOVs were issued, as well as an Administrative Order in February 2008 [Ref. 9, p. 1]

. PRASA closed the Hormigas water system and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in place [Ref. 7, p. 2; 10, p. 1; 11, pp. 15, 48, 54

- 56 ; 12, pp. 3

- 4].

EPA collected two ground water samples from the Euf racia well in September 2009, and the results confirmed the presence of PCE, this time at concentrations of 260

- 280 μg/L [Ref. 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16

- 18, 20

- 22 ]. TCE and cis

- 1,2 - DCE were also detected in the samples, at concentrations of 59

- 60 μg/L and 49

- 50 μ g/L , respectively [Ref. 13, pp. 16

- 18, 20

- 22 ]. The PCE and TCE concentrations detected in the Eufracia well significantly exceed the shared MCL of 5 μg/L [Ref. 2, pp. 7, 10]. Samples collected from several background wells showed non

- detects for PCE, TCE, and cis

- 1,2

- DCE [Ref. 11, pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17; 13, pp. 5
, 8-9
, 12 , 2 5 , 2 8
, 31

- 32 ].

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

The ground water plume is identified by contamination found in the former Eufracia public supply well . For the purpose of this report, th is well represent s a minimum of the plume extent. The well is located in interior, east

- central Puerto Rico and is shown in Figure 1

.

Containment

Release to ground water:

Based on evidence of hazardous substance migration (contamination detected in ground water samples collected from th e Eufracia well) and due to the fact that there is nothing to prevent the plume from migrating further, a containment factor of 10 is assigned [ Ref . 1, p. 51596; 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16

- 18, 20

- 22 ].10 SD - Hazardous Substances Source No.: 1

2.4.1 Hazardous Substances

Ground water samples collected by PRASA in 2006 and by EPA in 200 9 show ed the presence of chlorinated solvents in th e for mer Eufracia p ublic supply well, as described below. Background sample locations and contaminant levels for comparison to the contaminated samples are discussed in Section 3.1.1.

PRASA Sampling – Ground Water Sample: August 200 6

PRASA collected quarterly samples from the Eufracia well for compliance with safe drinking water regulations [Ref. 31, pp. 1 -5 ]. The results for a sample collected from the Eufracia well in August 2006 by PRASA indicated PCE at a concentration of 29 μg/L , as presented in the table below ( Note: PRASA reported its results and method detection limits [ MDL ] in mg/L , which EPA has converted to μg /L for consistency with the EPA data presented in this report ) [Ref. 8, pp. 1, 4 ; 31, p. 1 ]. The PRASA sa mple was collected and analyzed according to EPA Method 524.2 [Ref. 8, pp. 3

- 4]. The applicable concentration range of Method 524.2 can be 0.02

– 200 μg/L or 0.02

– 20 μg/L [Ref. 18 , p. 4]. The method requires a number of quality controls, including demonstr ations of capability, accuracy, and precision; analysis of blanks and surrogates; and determinations of MDLs for each analyte [Ref. 18 , pp. 16

- 19]. EPA defines MDL as the “lowest concentration of analyte that a method can detect reliably in either a sample or blank” [Ref. 1, p. 51586]. The PRASA analytical results include MDLs for all parameters , but do not establish sample quantitation limits (SQL; “quantity of a substance that can be reasonably quantified given the limits of detection for the methods of analysis and sample characteristics”) [Ref. 1, p. 51586; 8, pp. 3

- 4].

Hazardous Substance Sample Number Date Sampled Result (μg/L) MDL (μg/L) Reference PCE 06 H 2548 8/14/2006 29 0.50 8, pp. 1, 4

EPA Sampling Event – Ground Water Samples: August 200 9

EPA collected ground water samples HM

- GW01 and HM

- GW02 from the Eufracia well and background ground water samples HM

- GW04, HM

- GW05, HM

- GW06, HM

- GW07, HM

- GW08, and HM

- GW09 from several nearby wells in August

- September 2009 [Ref. 11, p p . 1 0- 17 ; 12, pp. 5, 9, 11, 17]. The EPA Region 2 Laboratory analyzed the samples for Target Compound List (TCL) trace concentration VOCs according to its Standard Operating Procedure (SOP) # DW

1, “Analysis of VOCs in Drinking Water by Purge & Trap GC/MS”, dated February 1 3, 2009 [Ref. 13, pp. 3, 54

- 58 ; 3 2, p. 1]. The SOP is based on EPA Method 524.2, as is the analytical method used by EPA’s Contract Laboratory Program (CLP) for trace concentration VOC analyses [Ref. 32 , p. 3; 3 3 , p. 68]. Although the analyses were not p erformed under the CLP, the EPA laboratory was able to achieve SQL s equal to the CLP Contract

- Required Quantitation Limits (CRQL) of 0.50 μg/L for PCE, TCE, and cis

- 1,2

- DCE [Ref. 1, p. 51585

- 51586, 51589; 13, p. 3; 19, pp. 1

- 2]. The Eufracia well

s amples ( HM

- GW01 and HM

- GW02 ) required a 50x dilution for quanti t ation of PCE and TCE, so the SQLs are adjusted accordingly to 25 μg/L (0.50 μg/L x 50) [Ref. 13, pp. 481

- 544 ; 32 , p. 18]. Chain

- of

- custody was maintained for the samples throughout collection, shipping, and analysis [Ref. 13 , pp. 39

- 58, 432

- 433 ].

PCE, TCE, and cis

- 1,2

- DCE were detected in the Eufracia well samples at individual concentrations ranging from 49 μg/L to 28 0 μg/L , but were not detected (ND) in the background samples , as presented in the table below [Ref. 12, p. 5; 13, pp. 5
, 8-9
, 12
, 16

- 18, 20

- 22
, 25 , 2 8
, 31

- 32 , 445

- 471 , 481

- 571 ]. Additional information regarding background conditions is presented in Section 3.1.1.11 SD - Hazardous Substances Source No.: 1

Hazardous Substance Sample Number Date Sampled Result (μg/L) SQL (μg/L) Reference

PCE HM

- GW01 09/01/2009 280 25 12, p. 5; 13, p p . 1 7, 504 HM

- GW02 09/01/2009 260 25 12, p. 5; 13, p p

. 21, 536 Background samples* 08/31/2009

– 09/01/2009 ND 0.50 12, p. 5; 13, pp. 5
, 9
, 12 , 2 5 , 2 8
, 32, 445

- 471, 545

- 571 TCE HM

- GW01 09/01/2009 60 25 12, p. 5; 13, p p . 1 7, 504 HM

- GW02 09/01/2009 59 25 12, p. 5; 13, p p

. 21, 536 B ackground samples* 08/31/2009

– 09/01/2009 ND 0.50 12, p. 5; 13, pp. 5
, 9
, 12 , 2 5 , 2 8
, 32, 445

- 471, 545

- 571 cis

- 1,2

- DCE HM

- GW01 09/01/2009 49 0.50 12, p. 5; 13, p p . 1 7, 481, 483 HM

- GW02 09/01/2009 50 0.50 12, p. 5; 13, p p

. 21, 512, 514 Background sampl es* 08/31/2009

– 09/01/2009 ND 0.50 12, p. 5; 13, pp. 5
, 8
, 12 , 2 5 , 2 8
, 31
, 445

- 471, 545

- 571

*Background samples include HM

- GW04, HM

- GW05, HM

- GW06, HM

- GW07, HM

- GW08, and HM

- GW09 [Ref. 11, pp. 10

- 17; 12, pp. 5, 9, 11, 17].12 SD

- Hazardo us Waste Quantity Source No.: 1

2.4.2 Hazardous Waste Quantity

2.4.2.1.1 Hazardous Constituent Quantity

The information available is not sufficient to evaluate Tier A source hazardous waste quantity; therefore, hazardous constituent quantity is not sco red (NS) [Ref. 1, pp. 51590

- 51591].

Hazardous Constituent Quantity (C) Value: NS

2.4.2.1.2 Hazardous Wastestream Quantity

The information available is not sufficient to evaluate Tier B source hazardous waste quantity; therefore, hazardous
wastestrea m quantity is not scored [Ref. 1, p. 51591].

Hazardous Wastestream Quantity (W) Value: NS

2.4.2.1.3 Volume

Because there is a well with samples showing contamination in the ground water but the volume of the contaminated area has not been determined , the volume of the ground water contamination is considered to be greater than 0 (>0) cubic yards but unknown [Figure 1; Ref

. 13, pp. 16

- 18, 20

- 22 ]. The source type is ‘Other,’ so the volume value is divided by 2.5 to obtain the assigned value, as shown below [Ref. 1, p. 51591, Section 2.4.2.1.3, Table 2 -5 ].

Dimension of source (yd 3 ) : >0 yd 3 Volume (V) Assigned Value: (>0)/2.5 = >0

2.4.2.1.4 Area

Tier D is not evaluated for source type “other” [Ref. 1, p. 51591, Table 2 -5 , Section 2.4.2.1.3 ].

A rea of source (ft 2 ): N/A Area (A) Assigned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source hazardous waste quantity value for Source 1 is >0 for Tier C - Volume [Ref. 1, p. 51591].

Source Hazardous Waste Quantity Value: >013 SD- Summary

SITE SUMMARY OF SOURCE DESCRIPTIONS

Source Number Source Hazardous Waste Quantity Value Containment Ground Water Surface Water Air (Gas) Air (Particulate) 1 >0 10 NS NS NS

NS = Not Scored14 GW

- General

3.0 GROUN D WATER MIGRATION PATHWAY

3.0.1 General Considerations

The site is located in an area underlain by volcanic and volcaniclastic basement rock s (i.e., bedrock) [ Figure 1; 20, p. 16 ; 22, pp. 11, 14 ]. The unit is considered to be a stratum of limited and lo cal ground water resources in Caguas , but it function s as a local source of water through fractures, joints, faults and the weathered

- bedrock mantle [Figure 1; Ref. 5, p. 1; 20, p. 16; 21, pp. 12

- 18 ; 22, p. 14 ]. T he well records for the Hormigas supply we ll show that it is 400 feet deep
, with an open

- hole screened interval in bedrock from 250 to 400 feet below ground surface (bgs) and a principal fracture from 300 to 3 05 feet bgs [Ref. 2 3 , pp. 1- 2, 4-5]

. The depth of the Eufracia well is 360 feet, and the depths of the nearby community supply wells range from 350 to 485 feet [Ref. 2 3 , pp. 1-2]

. T he wells are all located in the same topographic and geologic setting as the Hormigas well (i.e., volcanic and volcaniclastic rocks within the mountainous, interi or region of Puerto Rico) [Figure 1; Ref. 5, p. 1; 20, pp. 13

- 14, 16; 23, p. 1]. The wells are also located within a single hydrogeologic terrane (CaHT2) that extends throughout the western portion of Caguas [Ref. 23, p. 1 ; 36, pp. 10

- 12, 17]. The extent of this terrane beyond Caguas is unknown [Ref. 36, p. 17]. Based on these considerations, hydrogeologic terrane CaHT2 is evaluated as the aquifer under consideration, and only targets within the immediate site area are included for HRS scoring purposes [Ref. 1, p. 51595; 23, pp. 1

- 2; 36, pp. 10

- 12, 17]. The general direction of ground water flow in the site vicinity is east

- northeast [Ref. 20, p. 19].

The blended water supply system consisting of the Eufracia and Hormigas wells served an estimated popul ation of 5,488 people during its operation; according to PRASA , there were no other wells or surface water intakes contributing to the Hormigas system [ Ref. 6, pp. 1, 3- 4, 9, 15, 22, 31; 7, p. 2 ]. The capacities of the Eufracia and Hormigas wells are 150 and 100 gallons per minute (gpm), respectively [Ref. 23, p p

. 1-3 ]. Based on these capacities, the relative contribution of the Eufracia well to the total blended system was 60% (i.e., 150 gpm/250 gpm), and the population apportioned to the well is 3,293 people [Ref. 1, p. 51603; 23, pp. 1-3 ]. Ground water in Caguas is the primary resource used for commercial irrigation [Ref. 2 4 , p. 17]. Wellhead Protection Areas we re delineated for all potable water wells in Puerto Rico , so the plume lies within a design ated Wellhead Protection Area [ Ref

. 25 , pp. 29 -4 5; 26 , p. 1].

The volcanic bed r ock is described below:

Stratum 1/Aquifer

Stratum/Aquifer Name : Hydrogeologic Terrane CaHT2

Description : The v olcanic and volcaniclastic rocks that underlie the eastern hal f of Puerto Rico ’s i nterior ground

- water province are mostly Early and Late Cretaceous in age [Ref. 22, p. 14 ]

. Puerto Rico’s volcanic rocks include lava, tuff, breccias, and tuffaceous breccias [Ref. 20, p. 13]. Primary porosity of the rock s of the Inte rior province was destroyed by processes of compaction, diagenesis
, and tectonic movement [Ref. 22, p. 14 ]. Hydrogeologic terrane CaHT2 consists mainly of volcaniclastics, breccias, sandstone, siltstone with minor limestone lenses, and subordinate amounts of ash to lapilli tuff [Ref. 36, p. 1 1 ]. The slope of the unit is variable and the soil cover varies from less than two to about five feet [Ref. 36, p. 1 2 ]. Fracturing is not pervasive but is important locally, and well yields range mostly from 20

- 40 gp m [Ref. 36, p. 1 2]

. The average specific capacity in CaHT2 is 1 gpm per foot of drawdown, and depth to water ranges from 18

- 60 feet bgs [Ref. 36, p. 1 2]. Reported well depths in CaHT2 range from 135

- 500 feet bgs [Ref. 23, p. 2; 36, p. 17].15 GW

- Observed Release

3.1 LIKELIHOOD OF RELEASE

3.1.1 Observed Release

Aquifer Being Evaluated: Hydrogeologic Terrane CaHT2

An observed release is documented for the Hormigas Ground Water Plume site. Chemical analyses for ground water samples collected from the Eu fracia well in 2009 show the presence of chlorinated solvents [ Ref. 11, pp. 1 4- 15 ; 12, pp. 5, 9, 17; 13, pp. 1 6- 18, 20

- 22, 481

- 544 ].

Direct Observation

The aquifer is not evaluated for observed release by direct observation.

Chemical Analysis

EPA colle cted ground water samples HM

- GW01 and HM

- GW02 from the Eufracia well and background ground water samples HM

- GW04, HM

- GW05, HM

- GW06, HM

- GW07, HM

- GW08, and HM

- GW09 from several nearby wells in August

- September 2009 [Ref. 11, pp. 10

- 17; 12, pp. 5, 9, 11, 17]. The EPA Region 2 Laboratory analyzed the samples for TCL trace concentration VOCs according to its SOP # DW

- 1, “Analysis of VOCs in Drinking Water by Purge & Trap GC/MS”, dated February 13, 2009 [Ref. 13, pp. 3, 54

- 58; 32, p. 1]. The SOP is based on EPA Method 524.2, as is the analytical method used by EPA’s CLP for trace concentration VOC analyses [Ref. 32, p. 3; 33, p. 68]. Although the analyses were not performed under the CLP, the EPA laboratory was able to achieve SQLs equal to the CLP CRQLs of 0.5 0 μg/L for PCE, TCE, and cis

- 1,2

- DCE [Ref. 1, p. 51585

- 51586, 51589; 13, p. 3; 19, pp. 1

- 2]. The Eufracia well samples (HM

- GW01 and HM

- GW02) required a 50x dilution for quantitation of PCE and TCE, so the SQLs are adjusted accordingly to 25 μg/L (0.50 μg/ L x 50) [Ref. 13, pp. 481

- 544; 32, p. 18]. Chain

- of

- custody was maintained for the samples throughout collection, shipping, and analysis [Ref. 13, pp. 39

- 58, 432

- 433].

PCE, TCE, and cis

- 1,2

- DCE were detected in the Eufracia well samples at individual con centrations ranging from 49 μg/L to 280 μg/L, but were not detected (ND) in the background samples, as presented below [Ref. 12, p. 5; 13, pp. 5, 8

- 9, 12, 16

- 18, 20

- 22, 25, 28, 31

- 32, 445

- 471, 481

- 571].

Notes on sample similarity and background condition s: All background and contaminated samples documenting the observed release were collected from the aquifer under consideration [ Figure 1; Ref. 23, p p

. 1-2 ; 36, pp. 10

- 12, 17 ]. Samples from the La Sierra wells are evaluated as representative background samples because the hydrogeologic terrane, geologic setting, topographic setting, and elevation intervals are the same as the Eufracia well [Figure 1; Ref. 23, pp. 1-2 ; 36, pp. 10

- 12, 17 ]. The background and release samples were collected on the same day us ing the same sampling personnel and procedures [Ref. 11, pp. 14

- 17; 12, pp. 2

- 5, 17]. T he samples all were shipped to and arrived at the laboratory together, and they were all analyzed within the same laboratory batch under identical, acceptable QA/QC con ditions [Ref. 13, pp. 41, 52, 62 -64
, 481

- 571 ]. The compounds found in the Eufracia well are not naturally occurring, and the non

- detect concentrations in all the community supply wells show that the compounds are not ubiquitous in the area [Ref. 11, pp. 1 0- 12, 16

- 17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8

- 9, 12, 25, 28, 31

- 32; 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16].

Background Concentrations

During the August

- September sampling event, EPA collected ground water samples from the following community supply w ells in the Horm igas study area: Villa Vigia, El Paraiso, Los Velazquez, La Sierra 1, La Sierra 2, and La Sierra 3 [Ref. 11, pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17; ]. Chlorinated solvents were not detected in any of the community supply well samples [Ref. 13, pp. 5-6
, 8-9
, 11 -13
, 24

- 26 , 2 8- 29
, 31

- 32 ] . The La Sierra wells samples are considered most apt for comparison because the samples were collected on the same day as the Eufracia well samples, and the wells have similar geologic and topographic setting s , a s well as overlapping elevation intervals [ Figure 1; Ref. 5, p. 1; 12, pp. 5, 9, 17; 23 , p p

. 1-2 ]. The La Sierra wells are located 2,800

- 6,200 feet south

- south west of the Eufracia well, in a hydraulically16 GW

- Observed Release

sidegradient direction [ Figure 1; Ref. 20, p. 17].

Background Concentrations (continued)

Well Location Elev ation (ft AMSL) Well Depth (ft bgs) Bottom Elev

. (ft AMSL ) Sample Station ID Sample Date Reference(s)

La Sierra #1 1408 485 923 HM

- GW07 09/01/2009 12, pp. 5, 1 7; 23, p p

. 1

- 2 La Sierra #2 1456 400 1056 HM

- GW08 09/01/2009 12, pp. 5, 1 7; 23, p p

. 1

- 2 La Sierra #3 1465 485 980 HM

- GW09 09/01/2009 12, pp. 5, 1 7; 23, p p

. 1

- 2

ft AMSL = feet above mean sea level ft bgs = feet below ground surface

Sample ID Hazardous Subst ance Conc. (μg/L) SQL (μg/L) Reference(s) HM

- GW07 cis

- 1,2

- DCE ND 0.50 12, p. 17; 13, p p. 2 4

- 26, 41, 545

- 553 PCE ND 0.50 TCE ND 0.50 HM

- GW08 cis

- 1,2

- DCE ND 0.50 12, p. 17; 13, p p . 2 8

- 29, 41, 554

- 562 PCE ND 0.50 TCE ND 0.50 HM

- GW09 cis

- 1,2

- DCE ND 0.50 12, p. 17; 13, p p

. 31

- 32, 41, 563

- 571 PCE ND 0.50 TCE ND 0.50

Contaminated Samples

EPA collected two ground water samples from the Eufracia well in September 2009, and the results confirmed the presence of PCE, this time at concentratio ns of 260

- 280 μg/L [Ref. 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16

- 18
, 20- 22 ]. TCE and cis

- 1,2 - DCE were also detected in the samples, at concentrations of 59

- 60 μg/L and 49

- 50 μg/L , respectively [Ref. 13, pp. 16

- 18, 20

- 22 ]. The PCE and TCE concentrations detect ed in the Eufracia well significantly exceed the shared MCL of 5 μg/L [Ref. 2, pp. 7, 10].

Well Location Elevation (ft AMSL) Well Depth (ft bgs) Bottom Elev

. (ft AMSL) Sample Station ID Sample Date Reference(s)

Eufracia 1494 360 1134 HM

- GW01 09/01/20 09 12, pp. 5, 17; 23, p p

. 1

- 2 HM

- GW02 09/01/2009 12, pp. 5, 17; 23, p p

. 1

- 2

Sample ID Hazardous Substance Conc. (μg/L) SQL (μg/L) Reference(s) HM

- GW01 cis

- 1,2

- DCE 49 25 12, p. 17; 13, p p . 1 6- 18, 41, 481

- 511 PCE 280 25 TCE 60 25 HM

- GW02 cis

- 1,2

- DCE 50 25 12, p. 17; 13, p. 2 0

- 22, 41, 512

- 544 PCE 260 25 TCE 59 2517 GW

- Observed Release

Attribution:

EPA has not yet identified a surface source of the ground water contaminants in the Eufracia well. The compounds found in the well are not naturally occurring, and non

- detect concentrations in all the community supply wells show that the compounds are not ubiquitous in the area [Ref. 11, pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8

- 9, 12, 25, 28, 31

- 32; 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16]. PCE and TCE are man

- made chlorinated solvents that are commonly used in commercial/industrial operations such as dry cleaning and metal degreasing, while cis

- 1,2

- DCE is used to make solvents and is a common breakdown product of PCE and TCE [Ref . 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16]

. EPA has attempted to identify the source(s) of observed ground water contamination. In August and December 2009, EPA conducted reconnaissance effort s in the vicinity of the Eufracia well as part of a Site Dis covery Initiative to identify possible sources of ground water contamination [Ref. 11, pp. 3

- 8, 24

- 39, 42

- 46, 60

- 91]. EPA inspected 17 facilities in the area as possible sources of contamination [Ref. 11, pp. 3

- 8, 24

- 39]. EPA also performed an environmen tal database search, and conducted records searches and interviews to document site histories and regulatory status of possible source facilities [Ref. 11, pp. 3

- 9, 18

- 20, 24

- 39; 34, pp. 5

- 7, 11

- 16; 37, pp. 1

- 47]. As a result of the site discovery efforts , EPA identified direct evidence of PCE use at one facility (Mariel T

- Shirts), PCE storage at another facility (Narvaez Cleaners), and PCE emissions at a third facility (former Country Professional Dry Cleaners) [Ref. 11, pp. 6, 24

- 26, 42

- 43, 66, 74; 34, p p. 29, 41, 47; 35, p. 1]. EPA identified four other facilities as possible sources based on operational histories and observations made during facility inspections [Ref. 11, pp. 27

- 28, 31, 33

- 34, 37, 77

- 83, 88; 34, pp. 11

- 16]. The locations of the seven facilities identified by EPA as possible sources are shown in Figure 1.

In February 2010, EPA collected soil samples from the seven facilities identified as possible sources [Ref. 14, pp. 3

- 49; 15, pp. 3

- 27; 34, p. 16]

. PCE was detected at just one location (Narvaez Cleaners, as described below) [Ref. 15 , pp. 3, 5, 16, 2 1; 16, pp. 17, 20]. PCE was not detected in soil samples collected at other possible source locations, including facilities that are located between the contaminated sample and the Eufrac ia well [Ref. 15

- 17, all pages]. In addition, the Narvaez facility is located closer to six community supply wells where PCE was not detected (400

- 3,000 feet) than it is to the Eufracia well (4,400 feet) [Figure 1; Ref. 11, pp. 10

- 12, 16

- 17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8

- 9, 12, 25, 28, 31

- 32]. Two of the uncontaminated community supply wells are located north of the Narvaez facility, as is the Eufracia well [Figure 1].

It should be noted that the general direction of ground water flow from the site v icinity is east

- northeast [Ref. 20, p. 19]. During the site discovery efforts, EPA did not observe or identify any possible source facilities located hydraulically upgradient (i.e., west

- southwest) of the Eufracia well [Ref. 11, pp. 3

- 39; 34, pp. 5

- 6, 11

- 16, 21]. The environmental database search also did not identify any known possible source facilities within 1 mile of the site in that direction [Ref. 37, pp. 11

- 12].

Based on the above considerations, there is not sufficient evidence (i.e., data for in tervening areas) to attribute the ground water contamination in the Eufracia well specifically to sources at the Narvaez facility or any of the other facilities identified during EPA’s Site Discovery Initiative and sampling event; therefore, there is no id entified source(s) of contamination.

The seven facilities sampled by EPA in February 2010 are described below :

1. Taller Pototo

Taller Pototo is an auto body repair and painting shop that has been in operation since 2000 [Ref. 11, p. 30]

. T he owner/ope rator ceased commercial operations in approximately 2007 and has only work ed on personal cars at this location since then [Ref. 11, p. 31]

. Paint, paint thinner, and solvents are used in this process, including MX2 Binder Additive, GP 60 Lacquer Thinners, Metalux 2 2K MS Hardener Medium, MX2 VOC 4.2 Clear Light Speed; Metaluz 2 HS 2K Grey filler Primer, MX2 VOC 2.1 Clear, and DTM Primer Activator Medium [Ref. 11, pp. 30

- 31, 79; 34, p. 66]

. The filings from auto repairs are washed into a septic tank located beneath the floor of the garage [Ref. 11, p. 30; 34, p. 66] . During the facility inspection, EPA observed good housekeeping and did not see any spills or discharges [R ef. 11, pp. 30

- 31; 34, p. 66] . The garage is located at the edge of a vegetated cliff, adjacent to the owner ’s residence [ Ref

. 11
,18 GW

- Observed Release

pp. 30

- 31 ]. On February 25, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA Contract Laboratory Program ( CLP ) at the Taller Pototo facili ty [Ref. 14 , pp. 17

- 19 , 21 ; 15 , pp. 3, 7 -8
, 19, 26- 27]. PCE, TCE, and cis

- 1,2

- DCE were not detected in the soil samples [Ref. 17 , pp. 65 -85 , 101

- 10 3 ]. With the exception of methylene chloride and acetone at estimated concentrations in some samples, VOCs were not detected in soil samples collected at the facility [Ref. 17 , pp. 65

- 85, 101

- 103 ].

2. Mariel T

- Shirts

The Mariel T

- Shirts screen printing shop has been operated out of a private home in a residential area since 1999 [Ref. 11, p p

. 25

- 26 , 71 ; 34, p. 41] . T

- shirts are printed using an Octopus printing machine [Ref. 11, p p . 26, 71 ] . The screens are cleaned with mineral spirits and Ulano No. 60 Screen Filler, which contains no hazardous constituents [Ref. 11, p p

. 26 , 72 ; 34, p. 41] . Non

- toxic paint i s used for the T

- shirts [Ref. 11, p. 26]

. Superkleen stain remover, which contains 10% to 30% PCE, is used on T

- shirts [Ref. 11, p p . 26, 74 ; 34, p. 41 ; 35, p. 1 ] . The Superkleen is poured into a sprayer and sprayed directly onto the stain; water is not used in the stain

- removal process [Ref. 11, p p . 26, 74 ]

. A wash sink
, where equipment is cleaned, discharges directly to the ground surface behind the building , and there is a septic system located on the property [Ref. 11 , pp. 25

- 26 , 73, 75 ]. On February 22, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA CLP at the Mariel T

- Shirts facility [Ref. 14 , pp. 5

- 9; 15 , pp. 3, 5 -6
, 15, 22- 23 ]. PCE, TCE, and cis

- 1,2

- DCE were not detected in the soil samples [ Ref

. 16 , pp. 28 -51 , 64 -66 ]. With the exception of methylene chloride at estimated concentrations in some samples, VOCs were not detected in soil samples collected at the facility [Ref. 16 , pp. 28 -51 , 64 -66 ].

3. Narvaez Cleaners

Narvaez Cleaners is a retail/commercial dry cleaning business that has been operating at the current location since approximately 2004 [Ref. 11, p. 24; 34, p. 47] . Prior to Narvaez Cleaners, the building housed a pizzeria for fifteen years and it was a residential home prior to that [Ref. 11, p p . 25 , 63 ]

. T he facility operator indicated that it is a drop

- off location only and that the dry

- cleaning operations are conducted at another facility in Caguas [Ref. 11, pp. 24

- 25; 34, p. 47]

. H azardous waste transport documents indicate that waste PCE and TCE have been re moved from both properties [Ref. 34, p. 47]

. EPA observed poor h ousekeeping in the rear of the Hormigas facility , including t wo empty drums and two full
, partially

- rusted drums of PCE [Ref. 11, p p . 25
, 64, 66; 34, p. 47]

. A dry cleaning machine located at the facility was reportedly purchased in approximately 2006 but was never used [Ref. 11, p p . 25 , 63 ] . Bottles of household detergents and fabric softeners were scattered on the ground surface outside the laundry room on th e west side of the building [Ref. 11, p. 67; 34, p. 47] . A septic system located in the rear of the property receives wastewaters from both the laundry and the residence [Ref. 34, p. 47] . There were multiple broken dry cleaning and washing machines obser ved at the lower back portion of the site [ Ref

. 11, pp. 65, 67; 34 , p. 47 ]. On February 22, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA CLP at the Narvaez Cleaners facility [Ref. 14 , pp. 3

- 5; 15 , pp. 3, 5, 16, 21 ]. PCE was detected at a concentration of 19 micrograms per kilogram (μg/kg) in one surface soil sample and at an estimated concentration in the associated subsurface sample , but it was not detected in other soil samples collected at the facili ty [Ref. 15 , pp. 3, 5, 16, 2 1; 16, pp. 1 0- 27 ]. TCE
, cis

- 1,2

- DCE , and other VOCs were not detected in any of the soil samples [ Ref

. 16 , pp. 10 -27 ].

4. S an Lorenzo Busline

T he San Lorenzo Busline facility has been operating since 1989 repairing buses and trucks [Ref. 11, p. 33; 34, p. 54]

. During the facility inspection, EPA observed poor h ousekeeping practices , including oil stains in the garage area [Ref. 11, pp. 33

- 34; 34, p. 54] . Rusted paint cans, lacquer thinner (ChemSpec), and 5

- gallon buckets of diesel oil were observed inside and around the garage [Ref. 11, p. 33; 34, p. 54]

. According to the operator, t he facility does not currently use chlorinated solvents for degreasing [ Ref

. 11 , p. 33 ; 34, p. 54 ]. On February 24, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA CLP at the San Lorenzo Busline facility [Ref. 14 , pp. 14

- 15; 15 , pp. 3, 6 -7
, 17, 24

- 25 ]. PCE, TCE, and cis

- 1,2

- DCE were not detected in the soil samples [ Ref

. 17 , pp. 38 -64 ]. With the exception of methylene chloride and acetone at estimated concentrations in some samples, VOCs were not detected in soil samples collected at the facility [Ref. 17 , pp. 38

- 64 ].19 GW

- Observed Release

5. Country Professional Dry Cleaners.

On August 24

- 25 , 2 009, WESTON observed the vacant storefront with a faded sign, Country Professional Dry Cleaners [Ref. 11, p p . 6
, 8, 42

- 43 ; 34, p. 29] . At that time, the site had been closed for approximately one year [Ref. 11, p. 6]

. As of February 2010 , the facility wa s still vacant [Ref. 14
, p. 10] . A Multi

- system query on EPA’s website using Country Dry Cleaners indicated the address PR 172 Km 6.6, Bo. Cañaboncito Caguas, PR 00725, with minor violations related to PCE under Air Facility System ID 7202500126 [ Ref

. 34, p. 29 ]. On February 25 , 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA CLP at the Country Professional Dry Cleaners facility [Ref. 14 , pp. 19

- 20; 15 , pp.3, 7 -8
, 13, 26- 27 ]. PCE, TCE, and cis

- 1,2

- DCE wer e not detected in the soil samples [ Ref

. 17 , pp. 86

- 100 , 104

- 10 6 ]. With the exception of methylene chloride at estimated concentrations in some samples, VOCs were not detected in soil samples collected at the facility [Ref. 17 , pp. 86

- 100 , 104

- 10 6 ].

6. J R Auto Body Collision & Paint

T he JR Auto Body Collision & Paint facility is an auto body repair and paint shop that has been in operat ion since approximately 1989 [Ref. 11, p. 37] . During the facility inspection, EPA observed average housekeeping with n o spills or discharges [Ref. 11, pp. 37, 88; 34, p. 35] . Chemicals currently used at the facility include metal glaze polyester finishing and blending putty, OMNI base paint, and Nason 481

- 16 acrylic lacquer thinner [Ref. 11, p. 37] . Wastewater is discha rged to a septic tank behind the building [ Ref

. 11, p. 37; 34
, p. 35 ]. On February 24 , 2010, EPA collected one

sur face soil sample for TCL VOC analysi s through the EPA CLP at the JR Auto Body Collision & Paint facility
, and attempted unsuccessfully to collect additional surface and subsurface soil samples [Ref. 14 , pp. 15

- 16; 15 , pp. 3, 6, 14, 24 ]. PCE, TCE, and cis

- 1,2

- DCE were not detected in the soil sample [ Ref

. 17 , pp. 35 -37 ]. With the exception of methylene chloride at an estimated concentration, V OCs were not detected in the soil sample collected at the facility [Ref. 17 , pp. 35

- 37 ].

7. Taller Gonzalez

The Taller Gonzalez facility has performed auto body repair and paint services since 1997 , when t he garage was constructed [Ref. 11, pp. 27

- 28; 34, p. 60]

. EPA observed good housekeeping in the auto body repair and paint area and the remainder of the facility [Ref. 11, pp. 27

- 28] . The chemical products observed included a petroleum

- based solvent, an alcohol

- based paint thinner, ChemSpec paints, an d Dupont ChromaSystemTM Basemaker paint [ Ref

. 11 , pp. 27

- 28]. On February 24, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysi s through the EPA CLP at the Taller Gonzalez facility [Ref. 14 , pp. 12

- 14; 15 , pp. 3 , 6, 18, 24 ]. PCE, TCE, and cis

- 1,2

- DCE were not detected in the soil samples [ Ref

. 17 , pp. 11 -34 ]. With the exception of methylene chloride at estimated concentrations, VOCs were not detected in soil samples collected at the facility [Ref. 17 , pp. 11

- 34 ].

Hazardo us Substances Released:

Cis

- 1,2

- Dichloroethylene (cis

- 1,2

- DCE) CAS No. 000156

- 59 -2 Tetrachloroethylene (PCE) CAS No. 000127

- 18 -4 Trichloroethylene (TCE) CAS No. 000079

- 01 -6

================================================================================== Ground Water Observed Release Factor Value: 55020 GW

- Waste Characteristics

3.2 WASTE CHARACTERISTICS

3.2.1 Toxicity/Mobility

Hazardous Substance Source Numbers Toxicity Factor Value Mobility Factor Value Toxicity/ Mobility Reference

cis

- 1,2

- Dichloroethylene 1, OR 100 1.0 100 2, p. 4 Tetrachloroethylene 1, OR 100 1.0 100 2, p. 5 Trichloroethylene 1, OR 10,000 1.0 10,000 2, p. 10

OR = Observed Release

3.2.2 Hazardous Waste Quantity

Source Number Source Hazard ous Waste Quantity (HWQ) Value (Section 2.4.2.1.5) Is source hazardous constituent quantity data complete? (yes/no) 1 >0 No

Sum of Values: 1 (rounded to 1 as specified in HRS Section 2.4.2.2)

The sum corresponds to a hazardous waste quantity factor value of 1 in Table 2

- 6 of the HRS [Ref. 1, p. 51591]. However, based on the fact that targets are subject to Level I concentrations (see Section 3.3.2.3), a hazardous waste quantity factor value of 100 is assigned if it is greater than the hazardous wa ste quantity value from Table 2

- 6 (i.e., 1) [Ref. 1, pp 51591

- 51592]. Therefore, a hazardous waste quantity factor value of 100 is assigned for the ground water pathway [ Ref. 1, p p 51591

- 51592]

.

3.2.3 Waste Characteristics Factor Category Value

TCE corresponds to the toxicity/mobility factor value of 10,000, as shown previously (see Section 3.2.1).

Toxicity/Mobility Factor Value (10,000) x Hazardous Waste Quantity Factor Value (100): 1 x 10 6

The product (1 x 10 6 ) corresponds to a Waste Characteristics Factor Category Value of 32 in Table 2

- 7 of the HRS [Ref. 1, p. 51592].

================================================================================== Hazardous Waste Quantity Factor Value: 100 Waste Characteristics Factor Category Value: 3221 GW

- Targets

3.3 TARGETS

The Hormigas well water system serve d an estimated population of 5,488 people and withdr ew all of its water from the Eufracia and Hormigas public supply wells ; according to available information, there were no other wells or surface water intakes contributing to the Hormigas system [Ref. 6, pp. 1, 3-4 , 9, 15, 22, 31; 7, p. 2]. The capacities of the Eufracia and Hormigas wells are 150 and 100 gallons per minute (gpm), respectively [Ref. 23, p p

. 1-3 ]. Based on t hese capacities, the relative contribution of the Eufracia well to the total blended system was 60 % (i.e., 150 gpm/250 gpm)
, and the population apportioned to the well is 3, 293 people [Ref. 1, p. 51603; 23, pp. 1-3 ]. In response to a health

- based violati on (average PCE concentration exceeding the MCL) in 2006, the State issued Notices of Violation i n November 2007 and an Administrative Order in February 2008 [Ref. 8, pp. 1, 4; 9, p. 1]. PRASA closed the Hormigas water system and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in place [Ref. 7, p. 2; 10, p. 1; 11, pp. 15, 48, 54

- 56 ; 12, pp. 3

- 4]. The level of contamination in the Hormigas well is unknown , so only the apportioned population for the Eufracia well (base d on the population served by the well at the time of closure) is considered, as presented below:

Well Distance from Source (mi.)* Population Level I Conc. (Y/N)** Level II Conc. (Y/N)** Potential Contam. (Y/N) Reference(s)

Eufracia 0.0 3
, 293 Y N N Fig. 1; Ref. 6, pp. 1, 3- 4, 9, 15, 22, 31; 7, p. 2; 8, pp. 1 -8 ; 23, pp. 1

- 3

* Distance is measured from the center of the area of observed ground water contamination [Figure 1].

** Maximum Contaminant Level/Maximum Contaminant Level Goal (MCL/MCLG), Reference Dose Screen Concentration (RfD), and Cancer Risk Screen Concentration (CRSC) were used as benchmarks to evaluate the level of contamination [Ref. 1, p. 51593] . Applicable benchmarks for the contaminants detected in the observed release, presented here i n μg /L for consistency with reported data, are as follows:

Substance MCL/MCLG RfD CRSC Reference(s) cis

- 1,2

- DCE 70 360

--- 2, p. 6 PCE 5 360 1.6 2, p. 7 TCE 5 11 0.21 2, p. 10

Level I Concentrations

Well Sample Substance Conc. (μg/L) Benchmark (μg/L ) Reference(s) Eufracia HM

- GW01 PCE 280 1.6 (CRSC) 5 (MCL) 2, p. 7 ; 13, p. 1 7

TCE 60 0.21 (CRSC) 5 (MCL) 11 (RfD) 2, p. 10 ; 13, p. 1 7

HM

- GW02 PCE 260 1.6 (CRSC) 5 (MCL) 2, p. 7 ; 13, p. 21

TCE 59 0.21 (CRSC) 5 (MCL) 11 (RfD) 2, p. 10 ; 13, p. 2122 GW

- Nearest Well/Population

3.3.1 Nearest Well

As identified in Section 3.3, t he former Eufracia drinking water well is subject to Level I con centrations

. Therefore, a nearest well factor value of 50 is assigned [Ref. 1, pp. 51602

- 51603].

============= ===================================================================== Nearest Well Factor Value: 50

3.3.2 Population

3.3.2.2 Level I Concentrations

As identified in Section 3.3, the former Eufracia drinking water well is subject to Level I concentra tions . The population assigned to the well is also explained in Section 3.3.

Level I Well Population Reference(s) Eufracia* 3
, 293 6, pp. 1, 3

- 4 , 9, 15, 22, 31; 7, p. 2; 8, pp. 1

- 8 ; 23, pp. 1 -3

========================================================== ======================== Population Served by Level I Wells: 3, 293 Level I Concentrations Factor Value: 32
, 93 0

* PRASA disconnected the Eufracia well as of February 2009, but the pump remains in place [Ref. 7, p. 2; 10, p. 1; 11, pp. 15, 48, 54

- 56 ; 12, pp. 3

- 4].

3.3.2.3 Level II Concentrations

The people formerly served by the contaminated drinking water well ( Eufracia ) are already counted under the Level I concentrations factor. The Level II concentrations factor value is 0 because there are no o ther points of withdrawal subject to Level II concentrations [Ref. 1, p. 51603].

Level II Well Population Reference(s) N/A N/A N/A

================================================================================== Population Served by Level II Wells: 0 Level II Concentrations Factor Value: 0

3.3.2.4 Potential Contamination

Due to the fact that the maximum score of 100.00 for the ground water pathway is achieved, potential contamination was not evaluated.

================================================================================== Potential Contamination Factor Value: 023 GW

- Resources/Wellhead Protection Area

3.3.3 Resources

Available information indicate s that ground water is the primary resource used for commercial irrig ation in Caguas [Ref. 24, p. 17]. Therefore, a resources factor value of 5 is assigned [Ref. 1, p. 51604].

================================================================================== Resources Factor Value: 5

3.3.4 Wellhead Protection Area

The Wellhead Protection Program for Puerto Rico was developed in accordance with Section 1428 of the Safe Drinking Water Act and approved by EPA in 1991 [ Ref

. 25 , pp. 3

- 4; 26 , p. 1]. Every potable water well in Puerto Rico is within a wellhead protectio n area [Ref. 25 , pp. 29

- 45]. Based on this information, observed ground water contamination associated with the site lies within a designated wellhead protection area (i.e., at the contaminated Eufracia public supply

we ll), and a wellhead protection area factor value of 20 is assigned [Ref. 1, p. 51604].

================================================================================== Wellhead Protection Area Factor Value: 20