SFUND 2001 0009 0014 HAZARD RANKING SYSTEM (HRS) DOCUMENTATION RECORD  REVIEW COVER SHEET Name of Site:

Contact Persons: McGaffey and Main Groundwater Plume SiteInvestigationGeorge  Schuman. NMED. Proaam Manager (505) 827 2922 mame> (Phone)

DocumentationRecord: BrendaNixonCook. EPANPLCoordinator (214) 665 7436 mame) (Phone)

Pathwavs. Components. or Threats Not Scored 1) SurfaceWaterPathway: Thesurfacewaterpathwayhasnotbeenscoredbecausethereisno overland flow segment or flood potential for the site. Based on available information, evaluation  ' of the surface water pathway would not significantly affect the overall site score.

Soil Exposure: The New Mexico hvimntnent Department (NMED) conducted a limited shallow soil vapor study in the source .area m 1995. During this study, small bore holes were installed to depths of approximately 2 to 3 feet below ground surface (bgs). PCE concentrations were then measured m thevadosezone. The results revealeda high concentrationofPCElocated immediately south of the source area (Ref. 4, p. 6). A nested soil vapor well was later installed in October 1995 as a result of the initial soil vapor investigation PCE concenbdions measured in .the vapor samples ranged fiom 340 parts per million volume/ volume (ppm ViV) at 6 feet bgs and increased to 1,600 ppm VN at 38 feet bgs (Ref 4, p. 6).

The soil exposure pathway has not been scored because no area of surface soil contamination has been identified for the site.

3) Air Pathway: The air migration pathway has not been scored because an observed release to the air migration pathway has not been documented for the site. Based on available information, evaluation of the air migration pathway would not significantly affect the o v d site score.

HRS Documentation Record 05/ 30/ 01 1 McGaffey and Main Gmundwater Plume NM0000605386 HRS DOCUMENTATION RECORD NameofSite: McGaffeyandMainGrpundwaterPlume CERCLIS Site ID No.: '' ' NM0000605386 EPA Region: 6 Date County and State:

General Location within the State:

Topographic Map( s):

Latitude:

i ,>

Longitude: Chaves County, New Mexico Thesite is located in the City of Roswell, Chaves County, New Mexico. Roswell is located in the Southeastern portion of the state of New Mexico.

The following U. S. Geological Survey (USGS) 7.5 minute topographic series map( s) were used m locating the site: Rosivell North, New Mexico and Roswell South, New Mexico (Ref. 3, pp. 1 2):

3 3 0 22' 47.25" North (as measured from the intersection of McGaffey and Main Streets) (Ref 3, p. 3).

1040 3 1' 7.40" West .( as measured, from the intersection of McGaffey and Main Streets) (Ref. 3 ; p. 3). ., ' ,

...

Scores Aii. Pathway Not Scored Ground Water Pathway 100 Soil Exposure Pathway Not Scored Swface Water Pathway Not Scored HRS SITE SCORE 50 HRS Documentation Record 05/ 30/ 01 2 McGaffey and Main Groundwater'Plume NM0000605386 NOTES TO THE READER I . For thepurposesofthisHazardRanking System( HRS) DocumentationRecord, aplumeofcontaminated ground water has been identified in Roswell, Chaves County, New Mexico. The boundary of the plume is defined by ground water samples from domestic wells, monitoring wells, and municipal supply wells that meet observed release criteria under the HRS. The site has been evaluated as a ground water plume attributable to a source.

2. Thefollowingruleswereappliedwhencitingreferencesin this Documentation Record A. Trackingnumbers are assigned by theRegiontoeverypageofeveryreference. Thetracking number consists of the reference number followed by the page number within that reference. A tracking number has a two digit number followed by the sequential number (e. g., 040001, 040002, etc.).

B. If the reference has an original page number, that page number was cited.

C. If thereferencecitedhasnooriginalpagenumber or thepaginationisnotcomplete, thenthe designated tracking number was cited.

D. Analyticaldataarereferencedbytrackingnumberonly.

3. Hazardous substances are listed by the names used in the June 1996 SuperfundChemicalDataMa& (SCDM) (Reference 2). It should be noted that perchloroethylene is commonly referred to as PCE. Synonymsforperchloroethylenemclude: tetrachloroethylene, tetrachloroethene, andperc. These distinctiods have been made because some reports and/ or analytical data may refer to this substance in one ofthese manners.

4. AttachmentAof this DocumentationRecordconsistsofthefollowingfigures:

e A 1 Site Location Map e A 2 Well Location Map 0 A 3 Level I/ Level I1 Targets and Estimated Extent of Plume Map HRS Documentation Record 05/ 30/ 01 3 McGaiTey and Main Groundwater Plume NM0000605386 REFERENCES CITED 1. 40CFRPart300, HazardRankingSystem; FinalRule. 14December1990. Volume55, No. 241.

2. U. S. EnvironmentalProtectionAgency( USEPA): 1996. S u p e h d ChemicalDataMatrix( SCDM). June 1996.

3. U. S. Geological Survey (USGS). 1962; Photorevised in 1975. Roswell North and Roswell South, New Mexico (7.5 minute topographic series maps) and Latitude and Longitude Calculation Worksheet. Total pages: 3. ..

4. NewMexicoEnvironmentDepartment( NMED). Tetrachloroethene( PCE) Contamination of Ground Water, McGaffey and Main, South Roswell,$ New Mexico. ,. Total Pages: 84.

5. NMED. 1995. EmergencyAbatementProposalfor" Orphan" Water PollutionSites. 3 February1995. Total Pages: 8.

6. NMED. 1995. Memorandum to Mr. MarkE. Weidler, EnvironmentalSecretaryfortheState ofNew Mexico. Subject: Roswell PCE Investigation Workplan. 10 February 1995. Total Pages: 6.

7. NMED. 1995and2000. NotificationstoRoswellResidents of PCEContamination. Februaryand March 1995 and 21 Novernber 2000. Total Pages: 9.

8. NMED. 1995. Letterto Mr. DavidHarries, SecretaryofFinanceandAdministration, StateofNew Mexico. Subject: Emergency Funding for'Alternate Water Supply. 6 February 1995. Total Pages: 2.

9. NMED. 1998. SouthRoswellPCESiteGroundWaterMonitoringReport. 1998.. TotalPages: 15.

10: US. EnvironmentalProtectionAgency( USEPA). 1992. yazard RankingSystem Gdance Manuak Interim Final (excerpts). November 1992. Total Pages: 4.

1 1. State ofNew MexicoDepartmentofHealth. 1994 to 1995. Laboratory Analytical Reports. December 1994 through December 1995. Total Pages: ,139.

12. State ofNew MexicoDepartment of Health. 1998. LaboratoryAnalyticalReports. October1998. Total Pages: 26.

13. State ofNew MexicoDepartment of Health. 1999. LaboratoryAnalyticalReports. May1999. Total Pages: 45.. 8:" .

HRS Documentation Record 05130101 McGaffey and Main Groundwater Plume NM0000605386 14. StateofNewMexicoDepartmentofHealth. 2000. LaboratoryAnalyticalReports. April2000and September 2000. Total Pages: 72.

1 5. State ofNew Mexico Department of Health. 200 1 . Laboratory Analmcal Reports. March 200 1. Total Pages: 48.

1 6. State ofnew Mexico Department of Health. 2001. Laboratory Analytical Reports. April, January, and February 1995; July 1996; May 1999; and October 2000. Total Pages: 24.

17. StateofNewMexicoDepartmentofHealth. 1992 through 1999. LaboratoryAnalyticalReportsfor the City of Roswell Municipal Supply Wells. April 1992 through October 1999. Total Pages: 37.

18. New MexicoWaterResourcesResearchInstitute, 1982. "The Carbonate Aquifer of the Central RoswellBasin: Recharge EstimationbyNumericalModeling( excerpts)." Report NO. 142. February1982. TotalPages: 16.

19. USGS. 2001. GroundWaterAtlasoftheUnitedStates. "Carbonate rock Aquifers" and "Roswell Basin Aquifer System articles. February2001. TotalPages: 22.

20. Atkins Engineering Associates, Inc. 1994. Limited Site Investigation Report for the Heritage Investments Phase 11. 28 October 1994. Total Pages: 57.

2 1. Kambhu. A. 20Q1. WESTON. PersonalCommunicationwith Mr. JimEdwards, Manager, Ro, well Municipal Water System.. Subject: Roswell Municipal Supply Wells and Figures. 07 June 2001. Total Pages: 6.

22. HalogenatedSolventsIndustry Alliance, Inc. ( HSIA). 1999. Perchloroethylene. WhitePaper. November1999. TotalPages: 7.

23. U. S. Department ofcommerce. 2001. US. Census Bureau: 2000 Population and Housing Infomation. 30 June 2001. Total Pages: 3.

24. , EnvironmentalImprovementDivision, New MexicoHealthandEnvironmentDepartment. I 1990. Wellhead Protection Program for the State of New Mexico. Total Pages: 2.

HRS Documentation Record 05/ 30/ 01 5 McGaffey and Main Groundwater Plume NM0000605386 SITE SUMMARY The McGaffey and Main Groundwater Plume site is located Roswell, Chaves County, New Mexico, 88201 near the intersectionof SouthMain Street and McGaffey Street inan area ofmixedcommercialand industrialuse. Residential areas are located further southofthesite (Ref. 3, pp. 1 2). Essentially, thereisnoopenor undeveloped land within the immediate vicinity ofthe site (Ref 3, pp .I 2). The site consists of perchloroethylene (PCE) contamination that has been identified throughout the upper aquifer as a ground water plume that extends for approximately one mile in a southeasterly directioh (Ref 5, p. 2; Ref 9, p. 3).

The boundary of the ground water plume is defined by groimd water samples kom domestic, monitoring, and municipal supply wells. The precise extent of the plume has not yet been identified, but appears to measure approximately one mile in length (Ref 5 , p .2). There q e additional ground water plumes in the vicinity, however, only one ground water plume has been consid& ed for the puiposes of this documentation record since it is not known at this time'whether the PCEfound M e r down went of this site is commingled or otherwise related to this p h e (Ref. 6, p. 3.; Ref. 8, p. 2). The evidence. gathered to date appears to pqoint a former dry cleaning facility as the most likely source of the PCE contap& ation (Ref 4, p. 6; Ref. 9, p: 10).

The New Mexico Environment Department Dl has been the primary agency involved in the investigation of this ground water plume. The NMED discovekd the grouniwater plume in November B 994 following the investigation of a leaky underground storage tank at the former Pepsi Cola bottling plant (Ref 4, p. 3; Ref 20, p. 3). Ground water samples collected from moIiito& g wells installed as part of the investigation conducted at the former bottling plant revealed the presence o f w concentrations of PCE and gasoline ConstikJents. The highest concentrations ofPCE were observed across Southhkin Street fi omthe former bottling plant, in anarea referred to as the Highland Center (Ref 4, p. 3). ' ~

A large dry cleaning facility occupied a buildmg located at I 107 South Main Street of the Highland Center (Ref 4, p. 3). Records show that the dry cleaning facility operated from 1956 until 1963. The dry cleaning facility was known by the name of Lee Mack Laundry and Dry Cleaners (Lee Mack Cleaners) and ceased operation some time in 1963 (Ref. 4, p. 3; Ref. 20, p. 4). The owner ofthe dry cleaning facility is currently deceased (Ref 5, p. 1)

Extremely hgh concentmtions of PCE in a monitoring well located approximately 40 feet southeast ofthe former dry cleaning fxilityindicate that past d~ posal practices at the dry cleaning fxilitymayhave includmg discharging waste PCE behind the facility (Ref. 6, p, 1). PCE has been detected in this well at concentrations up to 25,000 micrograms per liter (ug/ L) (Ref 5, p. 1 ; Ref 6, p. I). During a site investigation in 1994, following a review of the locations of the PCE plume and the local dry cleaning facilities, it appeared that the PCE contamination could be a result of PCE discharges to the sewer line location in an alley east of Main Street (Ref. 20, pp. 5 6). Possible leakage ofthese sewer lines could have conkibuted to'the discharge ofthe PCE to the subsurface ground water (Ref 4, p. 3; Ref. 6, p. 1; Ref 20, p. 6). There are several dry cleaning facilities (both former and active) in the vicinity of the site (Ref. 4, pp. 52 54; 20, p. 4).

HRS Documentation Record 05/ 30/ 01 6 McGaffey and Main Groundwater Plume NM0000605386 The NMED has conducted several soil and ground water investigations in the area (Ref 4, p. 3). However, the precise extent of the PCE contamination in the ground water has not yet been determined. A brief s m a r y of the investigations conducted by the NMED is provided in the following paragraphs.

In February 1995, the NMED identified and sampled a total of 15 private domestic ground water wells and irrigation wells downgradient of the dry cleaning facility. These particular wells were identified by the NMED through a well record search and door to door surveys (Ref. 4, p. 4). The presence of PCE was detected in 1 1 of the 15 ground water wells. Concentrations of PCE ranged from 2.2 ug/ L to 250 ug/ L (Ref. 4, p. 4). The FederalMaximumContamhant Level( MCL) for PCE, as established. bythe Safe Drinking Water Act (SDWA), is 5 ug/ L (Ref 2).

At this time, the NMED discovered three residences whose sole source of water (including drinking) was from their domestic wells, which are completed in the shallow alluvial aquifer (Ref 4, p. 5; Ref 5, p. 2). PCE had b, een detected in two of the three domestic wells at concentrations of 79 ug/ L and 105 ugiL (Ref 6, p. 3). The NMED provided emergency funding to connect these residences to the City of Roswell system which receives its water from a deeper carbonate rock (artesian) aquifer (Ref 7, p. 1; Ref 8, p. 1).

A limited shallow ground water investigation was conducted by the NMED m 1995. A total of 13 monitoring wells were installed during this investigation at shallow, intermediate, and deep depths within the alluvial aquifer (Ref 4, p. 9. Ground water samples were collected by the NMED from these'monitoring wells in 1995. The PCE concentrations rangedfrom44 ugL to 25,000 ug/ L mthe shallowwells. Thehighest concentrations ofPCE were lbcated directly adjacent to the former dry cleaning facility. The PCE concentrations ranged from 1,000 ug/ L t6 14,000 ug/ L in the intermediate wells (Ref 4, p. 6).

A limited soil vapor investigationwas also conducted by the NMED in 1995. The limited soil vapor investigation consisted of drilling small bbre holes to depths ofapproximately 2 to 3 feet bgs. Soil vapor concentrations were then measured using a Photo Ionization Detector (PID). The results of this investigation revealed a high concentration of PCE located immediately south of the former Lee Mack Cleaners building (Ref 4, p. 7 ).

A nested soil vapor well wak later insialled in October 1995 as a result of the initial soil vapor investigation. Soil vapor samples were collected and analyzed for PCE. Concentrations of PCE ranged from 340 ppm VN at 6 feet bgs and increasing to 1,600 ppm VN at 38 feet bgs. This data suggested a substantial PCE residual in the vadose zone (Ref 4, p. 6).

Due to the need to carefiilly monitor changes m the plume chamcteristics, two ground water monitoring events were conducted in the vicinity of the glume during 1998 (Ref 9, p. 2). The first ground water monitoring event was conducted between 23 and 24 June 1998. Dunng this event, the integrity of the monitoring wells installed in 1995 were checked, static water levels were measured m these monitoring wells, and PCE concentrations detected in the nearby City of Roswell municipal wells were verified with city personnel (Ref 9, p. 2).

'HRS Documentation Record 05/ 30/ 01 7 McGaffey and Main Groundwater Plume NM0000605386 The second gmund water monitoring event was conducted between 24 and 25 September 1998. D u n n g .t h i s event, ground water samples were collected fiom 21 monitoring wells (Ref 9, p. 2). Analyhcal results of the 1998 ground water sampling indicatedthat'the average coricentrationof PCE detected was 4,808 ugL (Ref. 9, P. 5).

Between April and September 2000, the NMED identified a total of25 domestic groid water wells and irrigation wells downgradient of the dry 'cleaning hility. However, only 16 of the 25 wells identifed were sampled. The presence of PCE was detected in 13 ., ofthe 16 ground water wells. Concentratims of PCE ranged fiomO. 1 ugL to 193 ugL. In 2000, the PCE concentrations in the shallow wells ranged from, 18.4 ugL to 9,520 ugL. The PCE concentrations in the intermediate wells ranged fiom 5 1 ug/ L to 6,856 u& (Ref. 4, pp. 4,7).

Domestic wells and monitoring wells in which the presence of PCE had been previously identified were re sampled in March 2001. PCE continued to be detected at concentrations exceeding the MCL in these same domestic wells and monitoring wells (Ref. 15, pp: 1 48). ' ,

The City of Roswell has 5 municipal supply wells located within 2 miles of the ground water plume (Ref 21, p. 1). Routine compliance samphg is conducted by the kew Mexico Department ofHealth for all municipal supply wells to ensure compliance with drinking water stabdards as set forth in the Safe Drinking Water Act (SDWA) (Ref. 4, p. 5; Ref 5, p. 2). PCE has been detected inte& teeptly ii GO municipal supply weis beginning in 1995. These concentrations ofPCE range fiom 0.3 u& 'L to 2.3 ugL, PCE has also been detected consistently in two additionalmunicipalsupply wells s i r e 1993. The m u. 61 pncentration of YCE detected, ip these two public supply wells is 3.8 ug/ L. At present, the MCk'for PCE h+ not been exceeded (Ref. 4, pi 5; Ref. 5, p. 2). *I .,

Based on the analytical data accumulated to date, the concentrations of PCE in the ground water appear to be increasing with depth (Ref 9, p. 3). PCE is considered a dense non dgueous phase liquid @NAPL) that is heavier than water and, therefore, .w i l l sink in yater (Ref 6, pp. '2 3). Due to the high concentptions ofPCE that have been detected, it is probable that this DNAPL is not oniy present in the shallow ground water but .may also be remobilizing to greater depths within the aquifer (Ref 4, p. 7). Further, the confining unit present between the alluvial and artesian aqu$ ers, the Queen aquitard, ,is a leaky, confining unit thereby providing the flow path for the PCE to reach the lower aquifers (Ref. 4, p. 4; Ref. 6, p. 2; Ref: 18, p. 8). I 1 .

HRS Documentation Record 05/ 30/ 01 8 McGaffey and Main Groundwater Plume . NM0000605386 1.

2a.

2b.

2c.

3.

4.

5.

6. WORKSHEET FOR COMPUTING H R S SITE SCORE  S  s2 100 10,000 Ground Water Migration Pathway Score (S,) (fi om Table 3 1, line 1 3)

Surface Water OverlandRlood Migration Component (fi om Table 4 1, line 30)

Ground Water to Surface Water Migration Component (from Table 4 25, line 28)

Surface Water Migration Pathway Score (S,) (Enter the larger of lines 2a and 2b as the pathway score)

Soil Exposure Pathway Score (S,) (fi om Table 5 1 , line 22)

Air Migration Pathway Score (S3 (fi om Table 6 1, line 12)

Total of Sw2 + SSw2 + S: + S, '

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

Notes:

S Score S2 Scoresquared NS NotScored NS NS NS NS NS NS NS NS N S N S ""

50 Tables 3 1, 4 1, 4 25, 5 1, and 6 1 refer to scoresheets presented in the HRS Rule (Ref 1). Table 4 1 is reproduced on the following pages of this documentation record for the convenience of the reader.

HRS Documentation Record 05/ 30/ 0l 9 McGaffey and Main Groundwater Plume NM0000605386 SITE NAME: MCGAFFEYAND MAIN GROUNDWATER PLUME SITESCORE: 50 TABLE 3 ld GROUND WATER MIGRATION PATHWAY SCORESHEET Factor Cateyories and Factors Likelihood of Release to an Aquifer:

1. ObservedRelease 2. PotentialtoRelease: 2a. Containment 2b. NetPrecipitation 2c. DepthtoAquifer 2d. TravelTime 2e. Potential .to Release b e s 2a( 2b + 2c + id)] 3. Likelihood of Release (hgher of lines 1 and2e)

Waste Characteristics:

4. ToxicityMobility 5. HazardousWasteQuantity 6. WasteCharacteristics Targets:

7. NearestWell 8. Population Sa. Level I Concentrations 8b. Level II Concentrations 8c. PotentialContamination 8d. Population( lines8a + 8b + 8c) 9. 1 0. WellheadProtectionArea 11. Targets( lines7 + 8d+ 9 + 10)

HRS Documentation Record 05/ 30/ 01 10 MakimumValue Value AssiFned 550 550 10 10 5 35 500 550 NS NS NS NS NS 550 100 100 10 50 50 53.2 9,600.0 NS 9,653.2 5 20 9678.2 McGafEey and Main &oundwater Plume NM0000605386 SITE NAME: MCGAFFEY AND MAIN GROUNDWATERPLUMESITESCORE: 50 . TABLE 3 ld GROUND WATER MIGRATION PATHWAY SCORESHEET Ground Water Migration Score for an Aquifer:

12. AquiferScore[( lines3 x 6 x 11)/ 82,500] ([ lines 14 x 17 x 20]/ 82,500)

Ground Water Migration Pathway Score:

13. PathwayScore 100 100 100 100 (a) Maximum valueappliestowastecharacteristicscategory. (b) Maximum valuenotapplicable. (c) Do notroundtothenearestinteger. (d) Table 3 1. refers to scoresheets presented in the Federal Register (Reference 1). NS NotScored.

HRS Documentation Record 05/ 30/ 01 i.

11 McGaiTey and Main Groundwater Plume NM0000605386 I Source 1: Ground Water Plume SD  Characterization and Containment SOURCE DESCRIPTION 2.2 SOURCE CHARACTERIZATION Information pertaining to Source 1, Ground Water Plume, is provided in the following paragraphs.

2.2.1 Source Identification Number of the source: 1 Name and descriution of the source: Ground Water Plume with an unidentified source.

This source consists of a plume of containinated ground water and will be classified and evaluated as the HRS source type "Other (Ground Water Plume)" (Ref 10, p. 3). Although the contamination might be partially attributed to operations at the former Lee Mack Cleaners, the exact source of the contamination has not been identified. Therefore, Source 1 will be defined as a ground water plume with an unidentified source.

The boundary of the ground water plume is defined by ground water samples .collected from private domestic wells, monitoring wells, and municipal supply wells meeting observed release criteria. Private domestic wells used to define the estimated extent of tk ground water plume include the following seven wells: 1706 S. Atkinsoq 1806 S. Atkinson, 2304 S. Atkinson, 1105 E. Poe, ,1801 S. Cahoon, 2305 S. Cahoon, and 210 E. Reed. The monitoring wells used to define the estimated extent of the ground water p h e include those installed by the NMED consistingofED95 1 through ED95 13 as well as five additionalmonitoring wells: TH 4A, TH 74 TH 8A, TH 9, and TH 18. Municipal supply wells used to define the estimated extent of the ground water plume include four City of Roswell municipal supply wells: SRWl2, SRWl3, SRW 15, and SRWl6.

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

The 7 private domestic wells, 1 6 , monitoring wells, and 4 municipalsupply wells meeting observed release criteria are largely located mthe southwesternportionofthe City ofRoswell, approximately 2 miles west ofwhere South Main Street and U. S. Highway 285 converge (Ref. 3, pp. 1 2). The approximate boundary of the plume is bounded by McGaffey Street to the north, AtkinsonAvenue to the east, Poe Street to the south, and Main Skeet to the west as shown on Figure A 3 of Attachment A (Ref 3, pp. 1 2). Source M e for HRS evaluation purposes:

This source consists of a plume of contaminated ground water with an unidentified source and will be classified and evaluated as the HRS source type "Other (Ground Water Plume)." . ."

HRS Documentation Record 05i30i01 12 McGaffey and Main Groundwater Plume NM0000605386 Source 1: GroundWater Plume SD  Characterization and Containment Containment:

Gas release to air: The air migration pathway was not scored; therefore, gas containment was not evaluated.

Particulate release to air: The air migration pathway was not scored; therefore, particulate containment was not evaluated.

Release to ground water: There are no containment features associated with this source as it is a gound water plume. Further, evidence of migration of contaminants associated with the plume to the ground watei pathway has been aocumented in 7 private domestic wells, 1 6 monitoring wells, and 4 municipal supply wells (See Section 3.1 . 1 , Observed Release). Considering that analytical results ob'tained &om ground 'water samples collected between. the years of 1995 and 200 1 revealed the presence ofPCE and that no containment features are present to limit the migration of hazardous substances associated with the source, a containment factor value of 10 will be assigned to the somce (Ref. 1, Table 3 2).

Release by overland flow migration andor flood: The surface water migration pathway was not scored; therefore, surface water containment was not evaluated.

Release to soil: There is no surface soil available to sample at the site. Additionally, subsurface soil samples have not been collected to date. The entire site 1s covered with concrete thereby limiting the probability far persons to be impacted via soil exposure. As such, the soil exposure pathway d n o t be further evaluated hthis document.

HRS Documentation Record 05/ 30/ 01 13' McGaffey and Main Groundwater Plume NM0000605386 Source 1: Ground Water Plume SD  Hazardous Substances Associated with a Source 2.2.2 HazardousSubstancesAssociatedwithaSource Because this source is being evaluated and scored as a ground water plume with an unidentified source, all CERCLA eligible substances meeting observed release criteria have been, considered.

An observed release to an aquifer is established by demonstrating that the site has released a hazardous substance to the @er based either on direct observation or chemicalanalysis (Ref 1 , Sec. 3.1.1). An observed release based on chemical analysis is established as follows:,

If the background concentration is not detected (or is less than the detectionlimit), an observed release is established when the sample measurement equals or exceeds the sample quantitation limit (SQL). If the SQL cannot be established, the1 EPX coitract required quantitationlimit (CRQL) is used in place of the SQL for samples analyzed under the. EPA'Contract Laboratory Program (CLP). If sample analysis is not performed under the EPA CLP, the 'laboratory detection limit (DL) is used in place of the SQL (Ref 1, Sec. 2.3, Table 2 3).

Ifthe background concentration equals or exceeds the ,detectionlimit, an observed release is established when the sample measurement is three (3) times or more above the background concentration (Ref 1, Sec. 2.3, Table 2 3). t ,

Grohd water samples were collected by the NMED Ground Water Quality Bureaubetweenthe period of 1995 and 2001. During this six year period, PCE was continually detected in ground water samples collected fiom monitoring wells and private domestic wells. The ground3water samples were analyzed by the State of New Mexico's Department of Health laboratory (ie., the Scient& Laboratory Division) for VOCs only. Laboratory analyhcalresults fiomthe various NMED sampling events have been hcluded as References 11, 12, 13,14,15, and 16.

Additionally, routine. compliance sampling is conducted by the New Mexico Department of Health for all municipalsupply wells to ensure compliance with dnnhng water standards as set forth by the SDWA (Ref. 4, p. 5; Ref. 5, p. 2). Ground water samples collected i? om the municipalsupply wells are also analyzedbythe State ofNew Mexico's Department ofHealth laboratory. Laboratory analytical results hmthe municipal supply wells havebeenincluded as Reference17. '

As such, the analyticalredts presented m the following fables provide evidence ofPCE contamhationassociated with Source 1, Ground Water Plume, PCE has been detected on more than one occasion in the same well, but only the maximum concentration of PCE detected in the particular well has been presented as evidence of hazardous substances associated with Source 1 , Ground Water Plume.

HRS Documentation Record 05/ 30/ 01 14 McGaffey and Main Groundwger Plume NM0000605386 Source 1: Ground'Water Plume SD  Hazardous Substances Associated with a Source The New Mexico Department of Health laboratory utilized one of the following detection limits for comparison purposes: the Method Detection Limit @DL), the Practical Quantitation Limit (PQL), and/ or the Sample Detectionhit (SDL). A sample measurement exceeding one of these detection limits provides evidence of the presence of a particular substance. The specific type of detection limit utilized by the laboratory is denoted m the following table of analytical results.

HAZARDOUS SUBSTANCES ASSOCIATED WITH SOURCE 1 MONITORING WELLS ug/ Lmicrogramsperliter. PQLPractical Quantitation Limit; used for comparison purposes since the sample was not analyzed through the EPA CLP (Ref. 11, pp. 60

SDL Sample Detection Limit; used for comparison purposes since the sample was not analyzed through the EPA CLP (Ref. 12, pp. 13 26; 101).

Ref. 13, pp. 7 9; Ref. 14, pp. 16 18).

HRS Documentation Record 05/ 30/ 01 15 McGaiTey and Main Groundwater Plme NM0000605386 Source 1: Ground Water Plume SD  Hazardous Substances Associated with a Source HAZARDOUS SUBSTANCES ASSOCIATED WITH SOURCE 1 (continued)

PRIVATE DOMESTIC WELLS ..

HRS Documentation Record 05L30/ 018 16 McGaffey and Main Groundwater Plume NM0000605386 Source 1: Ground Water Plume SD  Likelihood of ReleaseNaste Characteristics 2.2.3 IdentifvHazardousSubstancesAvailable to aPathwav B, ecause containment for Source 1 is greater than 0, the following hazardous substances are available to the pathway being evaluated (ground water pathway): PCE.

2.3 LIKELIHOOD OF RELEASE Refer to Section 3.1 ofthis documentationrecord for specific infomationrelating to samples that meet the criteria for an observed release to the ground water migration pathway.

2.4 WASTE CHARACTERISTICS Specific factors related to waste characteristics associated with Source 1 are presented in the subsections below.

2.4 1 . Selection of SubstzincePotentiallyPosinptheGreatestHazard .

"Based'on the analytical results of ground water samples collected as part of the investigations conducted for the McGaffey and Main Groundwater Plume site, PCE was the only substance commonly detected in the ground water samples analyzed (Refs. 1 1 ; 12; 13; 14; 15; 16; 17). As such, PCE is the substance selected as potentially posing the greatest hazard for the pathway (threat] and will be used in evaluating the waste chai acteristks category of the pathway (threat) (Ref. 1, Sec. 2.4.1). For further information regarding PCE's association with Source 1, refer to Section 3.2. of this documentation record.

2.4.2 Hazardous 'Waste Ouantity <IP_ADDRESS>. SourceHazardousWasteQuantity <IP_ADDRESS>.1 HazardousConstituentQuantity( Tier A)  NotCalculated Thehazardousconstituentquantity is not available; therefore, it is not possible to adequately determine a hazardous constituent quantity (Tier A) for Source 1 (Ref 1, Sec. <IP_ADDRESS>.1). As a result, the evaluation of hazardous waste quantity proceeds to the evaluation of Tier B, hazardous wastestream quantity <IP_ADDRESS>.2HazardousWastestreamQuantity( Tier B)  NotCalculated The hazardous wastestream quantity is not available; therefore, it is not possible to adequately detennine a hazardous wastestream quant& (Tier B) for Source 1 (Ref 1, Sec. <IP_ADDRESS>.2). As a result, the evaluation of hazardous waste quantity proceeds to the evaluation of Tier C, volume (Ref 1, Sec. <IP_ADDRESS>.3).

HRS Documentation Record 05/ 30/ 01 17 McGaffey and Main Groundwater Plume NM0000605386 Source 1: Ground WaterPlume SD  Likelihood of ReleaseWaste Characteristics <IP_ADDRESS>.3 Volume( Tier C)

The vertical and horizontal extent ofthe ground water plume has not yet been adequately determined. Therefore, it is not possible to determine a volume in cubic yards for Source 1. Thus, the volume of contamination will be assigned a volume hazardous waste quantity value of greater than (>) 0 (Ref. 1, Sec. <IP_ADDRESS>.3).

Volume. of Source (yds3): > O Volume Assigned Value: Unknown, but > 0 <IP_ADDRESS>.4 Area( Tier D)

Area (Tier D) was not evaluated since a volume for the source has already been assigned <IP_ADDRESS>.5SourceHazardousWasteQuantity Value According to the HRS Rule, the highest of the values assigned to eachsource for hazardous constituent quantity (Tier A), hazardous wastestream quantity (Tier B), v o h e (Tier C), and area (Tier D) should be assigned as the source hazardous waste quantity value. As such, volume (Tier C) was the only tier evaluated for Source 1. Therefore, the v o h e determined for Source 1 yill be assigned as the source hazardous waste quantity for Source 1 (Ref. 1, Sec. <IP_ADDRESS>.5).

A Not Calculated B Not Calculated C Unknown, but > 0 ~

D I Not Calculated I I  I 1 Source Hazardous Waste Quantity Value: Unknown, but > 0 <IP_ADDRESS> HazardousWasteQuantityFactorValue According to the HRS Rule, if the hazardous constitueqt quantity has not beenadequately determined for one or more sources and if any target for the migration pathway being evaluated is subject to Level I andor Level I1 concentrations, a value fiom HRS Table 2 6 or a value of 100, whichever value is greater, is assigned as the hazardous waste quantity factor value for that pathway. Because both Level I and Levd 11 targets have been i d d e d for the ground water mi on pathway (the only pathway being evaluated) even though the hazardous constituent quantity has not been adequately determined, a value of 100 is assigned as the hazardous waste quantity factor value €or the ground water migration pathway (Ref. 1 , Sec. <IP_ADDRESS>, Table 2 6).

Hazardous Waste Quantity Factor Value: 100 HRS Documentation Record 05/ 30/ 01 18 McGaffey and Main Groundwater Plume NM0000605386 3.0 GW  General Considerations GROUND WATER MIGRATION PATHWAY 3.0.1 GeneralConsiderations The City of Roswell is located within the Pecos River Valley in southeastern New Mexico (Ref. 6, p. 2). The Roswell area has a semi arid climate which averages approximately 12 inches of precipitation per year, most of which occurs during summer thunderstorms (Ref. 18, p. 2). The mean mual air temperature in Roswell is approximately 59 degrees Fahrenheit with mild winters and hot summers (Ref 18, pp. 2,5).

The City of Roswell is located in the northern portion of the Roswell Ground Water Basin. Large volumes of ground water are withdrawn fiom a shallow alluvial aquifer and underlying carbonate rock (artesian) aquifer m the Roswell Basin. These two aquifers form the Koswell Basin Aquifer system (Ref 19, p. 10). The aquifer system undkrlies part of the Pecos River and extends though an area of about 2,200 square miles fiom. north of Roswell to northwest of Carlsbad, New Mexico (Ref. 19, p. 10).

Ground water in .@ e Permian aged carbonate rocks is present in openings formed by dissolution of part of the limestone, dolomite, and gypsuq~ that are prevalent m the rock. The most permeable and extensively utilized aqder in the carbonate rocks is in the Roswell Basin. This carbonate rock aquifer and the hydraulically connected aquifer mthe alhmiumhave been studied extensively because ofthe importance ofthis source ofground water (Ref 19, p. IO).

Ground water that flows through joints, fractures, or faults m soluble rocks composed of carbonate (limestone or dolomite) or evaporite (gypsum or halite) minerals can dissolve the surrounding rock and enlarge the openings. Over geologic time, a vast network of interconnected openings can develop in the rock, and large volumes of ground water can flow through the openings (Ref 19, p. 10). When solution altered rock becomes sufficiently porous, it may lack the strength to support the weight of overlying materials, and a broad gradual collapse of the rock can occur. The collapse reduces the thickness of the formation and creates additional h t u r e s that are subject to M e r dissolution. A local, and sometimes rapid, collapse of the rock can produce sinkholes and create a crater like appearance known as karst topography of the land surface (Ref. 19, p. lo)..

Where carbonate rocks are exposed at land surface, solution features create the karst topography. Because water, enters the carbonate rocks rapidly through sinkholes and other large openings, any contaminants present in the' water can rapidly enter an6 spread through the aquifer( s) (Ref 19, p. 6). According to available U. S, Geological Survey( USGS) documents reviewed,. the Roswell Basin Aqwfer systemis considered a karst aquSer (Ref 19, p. 10).

Ground water in the carbonate rock aquifer in the Roswell Basin primarily is present m solution altered zones m the San Andres Limestone and the overlying Queen and Grayburg Formations (Ref 19, p. 11).

HRS Documentation Record 05/ 30/ 01 19 McGaffey and Main Groundwater Plume NM0000605386 GW  General Considerations The San Andres Limestone is found at depths ranging from 300 to 1300 feet bgs. Limestone and dolomite are the principle rocks in the San Andres Limestone, although a 100 to 200 feet thick sandstone (the Glorieta Sandstone) is located near the base ofthe formation. The San Andres Limestone is 1200 to 1500 feet thick along the easternmargin ofthe Roswell Basin, but thins to 700 to 1,000 feet mthe northwesternpart ofthe basin where dissolution and collapse have decreased the thickness of the formation (Ref. 19, p. 11).

The Grayburg And QueeriFormations overlie the SanAndres Limestone. The Grayburg Formation predominantly consists of dolomite and gypsum with interbedded sandstone and shle. 'The Queen Formation consists ,of fine grained sandstone and siltstone with interbedded gypqm. The two formations are between 400 and 800 feet thick along the eastemmargin of the basin and thin westward as the result of erosion and, dissolution (Ref. 19, p. .,

11). ,,

,I ,,

The Seven Rivers, Yates; and Tamil Formations overlje the Queen Formation and crop out at higher altitude than the alluvium m the northern part ofthe Roswell Bask. These three formations consists of dolomite, limestone, and gypsum with interbedded sandstone and siltstone (R$. 19, p. 1 1).

Quaternary aUuvium that consists of unconsdlidated myel, sand, sil4 and clay unconf& nably overlies the Permian aged rocks m the Roswell Basin. Aliuvik~ &d associated terrace deposits ifom a 10 to 20 mile wide ban&, primady to the' west of the Pecos Rivkr." &e alluvium generally is about 150 to 300 feet thick near the Pecos River and thins to the west (Ref. 19, pp. 1 1 12). ,, ,. ,

,,

The alhrvnrm, present at the sMace, contains water under unconfined (water table) conditions. The alluvial @er is hydraulically connected to the underlying carbonate rock aquifer by leakage through the upper confining unit of the carbonate rock) aquifer. The water table in the" alluvial aquifer is at or near land surf= along. most of the Pecos River (Ref. 19, p. 12).

Solution altered zones in the San Andres Limestone and the Grayburg Formation form the principal carbonate rock acpfer in the Roswell Basin. The carbonate rock aquifer is 200 to 500 feet thick in the eastern one half of the Roswell Basin and thins northward and westwarg,( Ref. 19, p. 12).  The lower boundary of the aquifer is formed by the unaltered lower part of the San 'hdres Limestone or Glorieta Sandstone, or the underlying Yeso Formation. The upper part of the Grayburg and Quekn Formations generally are little ,altered and have low permeability. The zones of low permeability ih these two formations form the upper confining unit of the carbonate rock aquifer and separate it fkom the .overlying alluvial aquifer (Ref. 19, p. 12). This confining unit is estimated to be between 50 feet and 100 feet thick ih' the Roswell 'area (Ref 4, p'. 4). . I, ,

Interaqder leakage occurs between the carbonate rock aquifer and the overlying alluvial aquifer though the Queen quitard (Ref 18, pp. 8). Leakage is generally gfeatest m the vicinrty of Roswell and decreases to the south and southwest. Prior to the development of irrigation; wells, water leaked vertically upwards:, fiom the carbonate rock aqui6er to the alluvial a@&. At present, the'large 'drawdown of the potentiometric surface in the carbonate rock a w e r during the summer irrigation season reverses the direction of vertical lqakage (i. e., leakage is downward from the alluvial aquifer into the carbonate rock aquifer) (Ref 18, pp. 8 9).

HRS Documentation Record McGaf€ ey and Main Groundwater Plume 05/ 30/ 01 20 NM0000605386 GW  General Considerations Historically, regonal ground water flow in the Roswell area has been to the southeast toward the Pecos River with the mountains and fmthdls to the west of the Pecos River being the recharge zones. However, both vertical and horizontal flow directions have been altered locally by ground water withdrawal (Ref 4, p. 4). Locally, the direction of grouid water flow is to the southeast (Ref. 20, p. 5).

The City of Roswell is a large agriculture area (Ref. 6, p. 2). In 1978, approximately 95 percent of the ground water withdrawn from the Roswell Basin was used for irrigation.. In 1985, approximately 88 percent of the ground water withdrawn fiomthe basin was used for &gationand approximately 8 percent was used for public supply. Large capacity wells completed m the carbonate rock aqder generally yield in excess of 3,000 gallons per minute (gpmj. Smaller capacity wells commonly yield 500 to 1,000 gpm (Ref. 19, p. 16).

The City of Roswell's piimary drinking water supply resides in the carbonate rock (artesianj aquifer. The City of Roswell's public water supply system, known as the Berrendo Public Water System, and most of the water utilized for irrigation purposes in the Pecos Valley is fiom the carbonate rock aquifer (Ref 4, PA).

8 .

Several private domestic wells are located within 1.5 miles downgradient of the identified ground water plume. Additionally) 5 municipal supply wells are located within 4 miles of the identiiied ground water plume (Ref. 21, p. 1).  All of the municipal supply wells for the City of Roswell are completed within the carbonate rock (artesian) aquifep (Ref. 6, p. 2; Ref. 21, p. 1).

In the vicinity of the site, the alluvial deposits are composed of clay, silt, sand, and gravel with some caliche intermixed. The thickness ofthese alluvial deposits is approximately 150 to 200 feet. Depth to waterranges from approximately ,10 to 50 feet bgs (Ref 6, p. 2). The confining unit underlying the alluvial deposits is composed of interbedded kandstone, siltstone), claystone, and carbonate material. The thiclcness of the confining unit in the vicinity ofthe site has been measured between 30 to 50 feet (Ref 6, p. 2). As previously stated, the confining unit is not completely impermeable and leakage is known to occur. Deposits of the San Andres Limestone underlie the confining unit beneath the site and consist largely of limestone and dolomite (Ref. 19, p. 1 1).

HRS Documentation Record 05/ 30/ 01 21 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release 3.1 LIKELIHOOD OF RELEASE 3.1.1 Observed Release The ground water migrationpathway is the only pathway being scored for the McGaffey and Main Groundwater Plume site due to the nature of the contamination (i. e. 7 ground water plume) (Ref 1, S e c . 2.2.3). Identification and characterization of the ground water plume was based on analytical results from ,ground water samples collected over a six year period between 1995 and 2001.

An observed release to the Gromd Water Pathway, as defined in Section 3.1.1 of the HRS Rule, has been established based on the analytical results fkom the aforementioned ground water samples (Ref 1, Sec. 2.3). Informationused to evalyate and score the groyrid waterqiptionpathwayispresented mthe subsections below.

The City of Roswell is located in the northern portion of the RosweU. Ground Water Basin. Large volumes of ground water are withdrawn from a shallow du&& upif$ r and underlying carbonate rock (artesian) aquifer in the Roswell Basin. The carbonate rock aquifer 'and the'hydraulidly connected aqda in the alluvium form the Roswell Basin A q d a system which is the aquifa s y s t ~ b& g evaluated for this site. q e f 19, p. 10). Further, the @as of the Roswell Ground Water Bas@ . ,I have 'been classified as karst aquifers by the USGS (Ref. 19, p. 10). . , ' .I ,,

,~

Because of the dissolution cavities and the channels that comprise them, karst aquifers are considered extremely vulnerable to contamination. The movemqt ofhazardoussubstancesreleasedinto karst aquifersishighly unpredictable, and transport over relatively long distances can occur very rapidly (Ref. 10, p. 4). The City of Rosweuls primarydrinking water supply resides m the carbonate rock (artesian) aquifa and the municipal supply wells are completed within the carbonate rock (artesian> .aquifer (Ref. ,2 1 p. 1).

Interaquifer leakage occurs between the alluvi, d aquifer and the carbonate rock (artesian) aquifer through the Queen aquitard (Ref 18, pp. 8). Leakageisgenerallygreatest in thevicinityofRoswell. Priortothe development of irrigation wells, water leaked vertically upward fkom the carbonate aquifer to the alluvial aquifer. At present, the large drawdown of the potentiometric surface in the carbonate rock aquifer during the summer irrigation season reverses the directionofverticalleakage (i. e., leakage is downward hmthe alhwialaquifer into the carbonate rock aquifer) (Ref. 18, pp. 8 9).

Direct Observation: Not Applicable Chemical Analysis: Evidence documenting an observed release by chemicalanalysis is presented in the following paragraphs. The presence of PCE has been detected m both the shallow alluvial aquifer and the underlying carbonate rock (artesian) aquifer (See Section 3.1.1. Observed Release, Release Wells).

HRS Documentation Record 05/ 30/ 01 22 McGaffey and Main Groundwater Plume NM0000605386 BACKGROUND WELLS Ground water samples used to establishbackground levels for PCE for the domestic wells and monitoring wells were based on analytical results li om sampling events conducted between the years of 1995 and 2001 by the NMED (Ref 16, pp. 1 24). Ground water samples used to establish background levels for PCE for the municipal supply wells were based on analytical results li om samples collected between the years of 1992 and 1999. Ground water samples collected li om municipal supply well SRW17, which has been designated to represent backpund conditions of the municipal supply system, were collected as part of routine compliance sampling mandated by the Safe Drinking Water Act (Ref 17, pp. 3 1 37). It should be noted that a separate background investigation was not conducted for the site. Ground water wells that have been designated as background wells have been depicted on Figure A 3 of Attachment A.

Regionally, ground water flow in the Roswell area has historically been to the southeast toward the Pecos River. Locally, 'ground water flow within the vicinity of the site is to the southeast (Ref. 4, p. 4; Ref. 20, p. 5). Thus, ground water wells representative of background conditions for the area were chosen based on their location beirig upgradient or cross gradient of the approximate location ofthe identified ground water plume (Ref. 3, pp. 1 3; Ref. 21, p. 6; Figure A 3).

All of the ground water samples were collected and analyzed in a similar manner (i. e., collected using the same sampling techniques and analyzed under the same analyticalmethods). Further, all of the domestic and monitoring well ground water samples were collected by the same agency (NMED) and analyzed by the same laboratory (Refs. 4,9, 1 1, 12, 13, 14, 15, and 16). Likewise, all of the samples collected from the municipal supply wells were analyzed by the same laboratory (Ref 17, pp. 1 37).

PCE is a manufactured chlorinated solvent and does not occur naturally within the environment (Ref 22, p. 1) Therefore, the background level of 0 for PCE can be considered representative of background conditions ofthe area. As such, an observed release to the ground water d b e established when the sarnple measurement equals or exceeds the sample specific SQL or the detection limit imposed by the laboratory (Ref 1, Table 2 3, Sec. 2 31.

HRS Documentation Record 05/ 30/ 0 1 23 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release BACKGROUND DOMESTIC WELLS The 1 50 1 E. Beech Street well is a domestic/ irrigation well located north/ northeast of the identified boundary of, the ground water plume (Ref. 3, pp 1 2; Ref 21, p. 6; Figure A 3). This well was sampled by the NMJZD in 1994 and 1995 (Ref. 11, pp. 1 5,41 45). The total depth of the 1501 E. Beech Street well is approximately 220 feet bgs (Ref. 11, p. 1).

The 1403 E. Beech Street well is a domestic/ irrigation well located northhortheast of the identified boundary of the ground water plume (Ref 3, pp. 1 2; Ref. 2 1, p. 6; Figure A 3). This well was sampled by the NMED in 1995,1996, and 2000 (Ref. 16, pp. 9 17). The total dep$ of &e well has been measured at 185 feet bgs and the screened interval of this well is 165 feet to 170 ,8 feet . (Ref . , '4, p. 28).

The 1503 E. Holland well is a domestic well located north of the identified boundary of the ground water plume (Ref 3, pp. 1 2; Ref 2 1, p. 6; Figure A 3). .This'well was sampled by the NMED in 1995 (Ref. 16, pp. 20 24). The total depth and screened interval of the well +e &oG; however, most of the domestic wells in the area are completed mthe shallow alluvialaquifer and were screened fiomdepths ranging between 1 30 feet to 180 feet (Ref. 4, pp. 5). 8 ,

Even though these wells are located very near the estimated boundaries of the ground water plume, they are considered to be located outside the intluence ofpotential'contmination. Local ground water flow is towards the ~

southeast which would be away from these $eks (Ref 4, p. 4; Ref. 20,, p. 5). Further, since PCE concen@ tions have either been non detect or below the .detection limit established by the laboratory combined with the fact that PCE is not a naturally o c h g substance &the environment, these wells are considered representative of background conditions for the area.

BACKGROUND RESULTS  DOMESTIC WELLS Hazardous Substance Concentration in ug/ L (Detection Limit)

Perchloroethene ND (MDL = 1) . ND( PQL = 1) ND (PQL = 1)

References Ref. 16, pp. 20 24; Ref. 4, p. 5 Ref. 11, pp. 41 45; Ref. 4, pp. Ref. 1 1, pp. 2 5; Ref. 4, p. 28 Notes: ug/ L microgramsperliter. PQL hactical Quantitation Limit; used for comparison purposes bythe lab since the sample was not analyzed through the EPA CLP (Ref.

MDL MethodDetection Limit; usedforcomparisonpurposesbythelabsincethe sample wasnotanalyzed through the EPA CLP (Ref. 16, 11, pp. 1 5; 41 45).

pp. 20 24).

HRS Documentation Record 05/ 30/ 01 24 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release BACKGROUND RESULTS  DOMESTIC WELLS (Continued)

Ref. 16, pp. 17 19  Notes:

ug/ L micrograms per liter. PQL Practical Quantitation Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref.

MDL Method Detection Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 16,

SDL Sample Detection Limit; usedfor comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 16, 16, pp. 1 8).

pp. 9 14).

pp. 1 8, 14 19).

HRS Documentation Record 05/ 30/ 01 25 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release BACKGROUND MUNICIPAL SUPPLY WELLS Municipal supply well SRW 17 is located upgradient and southwest of the former dry cleaning facility as well as of the estimated boundary of the ground water plume (Ref. 3, pp. 1 2). Municipal supply well SRW17 is completed within the carbonate rock (artesian) aquifer at a total depth of 348 feet bgs (Ref 2 1, pp. 1,6), The depth to water has been measured to be approximately 53 feet in this. well (Ref. 21, p. 6). Concentrations of PCE in municipal supply well SRWl7 have been non detect fiom 1 992 through 1999.

MUNICIPAL SUPPLY WELL SRWI'I SRW17 Ref. 17. n. 33 POL = 0.5 ND 02/ 02/ 94 OR 94 0287 SRW17 Ref. 17, p. 32 MDL = 1 .O ND . 04/ 26/ 93 OR 93 0858 SRW17 Ref. 17, p 31 MDL = 1 .O mlL jYD, , 04/ 15/ 92 OR 92 0789 ,.

SRW17 ~ ~~~

\a 171602 1011 3/ 99 Ref. 17, pp. 36 37 SDL = 0.5 ,oND',, ' OR 9902234 SRW 17 Ref. 17, pp. 34 35 MDL = 0.5 , :. , ND', 10/ 28/ 96 ,,. '

Notes:

u g L micrograms per liter. MDLMethodDetection Limit; usedforcomparisonpurposes by the .lab since the sample was not analyzed through the, EPA' CLP (Ref. 17,

PQL Practical Quantitation Limit; used for comparison purposes by the lab since 'the sample was not analyzed through the :EPA CLP (Ref. ,,

,,

8 ,

pp. 31 32 and 34 35).

17, p. 33).

pp. 36 37). SDL Sample Detection Limit; used for comparison purposes by $e lab since the sample was not analyzed through the EPA CLP (Rcf. 17,

HRS Documentation Record 05130/ 01 26 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release RELEASE WELLS The NMEiD has been the primary agency involved in the investigationof this ground water plume. The NMED discovered the ground water plume inNovember 1994 followingthe investigationof a leaky underground storage tank at the former Pepsi Cola bottling plant (Ref. 20, p. 4). Ground water samples collected fiom monitoring wells installed as part of the investigation conducted at the former bottling plant revealed the presence of hi& concentrations ofPCE and gasoline constituents. The highest concentration of PCE were observed across South Main Street from the former bottling plant, in an area referred to as E. Iighland Center (Ref. 4, p. 3).

A large dry cleaning fzility occupied a building located at 1 107 South Main Street of the Highland Center. Records show that the dry cleaning facility operated from 1956 until 1 963. The dry cleaning facility was known by the nhme of Lee Mack Laundry and Dry Cleaners (Lee Mack Cleaners) and ceased operations some time in 1963 (Ref. 4, pl 3; Ref. 20, p. 4).

Ground water samples collected &om monitoring wells, private domestic wells, and municipal supply wells used to document an observed release to ground water have been presented inthe following tables by sampling event. Release samples are compared to the most appropriate background sample when available. Background . samples were considered .comparable and appropriate based on a similar sample date sampled and similar screened interval of the well.

The five municipal supply wells used to evaluate this site under the HRS are all completed within the carbonate rock (artesian) aquifer at depths of 344 feet, 346 feet, 348 feet, 363 feet, and 365 feet bgs. Depth to water in the five municipal wells have been measured at 53 'feet, 74 feet, 82 feet, 87 feet, and 115 feet (Ref. 21, p. 6). Thus, the total depths *of all of the municipal wells are similar. Therefore, the municipal well ,chosen to represent background (SR& 17) can be, considered comparable to the other four municipal wells (SRW12, SRW13, SRW15,: and, SRW16). I The extent of the ground water plume has been defined by ground water samples meeting the observed release criteria set forth in the HRS Rule. Ground water well locations have been depicted on Figure A 3 of Attachment A.

HRS Documentation Record 05/ 30/ 01 27 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release 1995 DOMESTIC WELL S& PLING EVENT In 1995, the NMED identified and sampled a tog1 of 15' domestic and higation wells located downgradient of the former dry cleaning facility These particular wells were identified by the NMED through a well record search and door to door surveys (Ref. 4, p. 4). Ground water samples were collected between January 1995 and June 1995 (Ref. 11, pp. 6 59).

At this time, the NMED discovered three residences whose sole source of water, including drinking, was fi om their domestic wells. Concentrations of PCE m two of the three wells exceeded the MCL for PCE. These domestic wells were completed within the shallow alluvial aquifer (Ref 4, p .5). ,The NMED provided emergency hding to close these wells and connect these residences to the, City ,of Roswell municipal supply system (Ref 5,. p. 2; Ref. 8, p. 1). The three domestic wells whichwere closed included the following wells:. 2305 S. Cahoon, 1706 S. Atkinson, and 1 801 S. Atkinson. It shoddbe noted that wen though the wells wek'closed for drinking water supplies, the wells were not plugged in 'order to continue the collection of samples h m these weils in an effort to 'monitor the characteristics of the PCE contamination. , '

~. 1995 DOMESTIC WELL SAMPLING RESULTS ,. ,

,,

I. ' b' .

Hazardous Substance ,m *

Concentration in ugii (Detection Limit) , , *, '8 Perchloroefhene 60 (MDL = 1) 79 (MDL = 1 ) 105 (MDL = 1)

Refmces Ref. 11, pp. 16 20; Ref. 4, p. 5Ref. 11, pp. 11 15; Ref. 4, p. 5 Ref. 11, pp. 6 10; Ref. 4, p. 5 1L  Notes:

ug/ L micrograms per liter. MDL MethodDetection Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 1 1 , ' t "

pp. 6 10).

HRS Documentation Record 05/ 30/ 01 28 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release 1995 DOMESTIC WELL SAMPLING RESULTS (Continued)

Hazardous Substance ~ Concentration in ug/ L (Detection Limit)

Perchloroethene 40 (MDL = 1) 6.10 (MDL = 1) 1 I Ref. 11, pp. 26 30; Ref. 4, pp. 28, 79 I Ref. 11, pp. 36 40; Ref. 4, p. 29, 79 Hazardous Concentration in ug/ L (Detection Limit) I Perchloroethene I 1 References 1 Ref. 11, p ug/ L micrograms per liter. MDL Method Detection Limit; used for c( pp. 36 59). 260.00 (MDL = 10) I 53.00 (MDL = 5) , II mison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 11,

HRS Documentation Record 05/ 30/ 01 29 McGafSey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release 1995 GROUND WATER INVESTIGATION A limited ground water investigation was conducted m 1995 by the NMED. The ground water investigation focused on the area surrounding the former dry cleaning facility. A total of 13 monitoring wells were installed during this investigation: ED95 1 through ED95 13. Shallow, intermediate, and deep ground water monitoring wells were installed (Ref 4, pp. 6 7). Shallow ground water wells are classified as those wells completed between 40 feet and 60 feet bgs and screened approximately 5 'feet to 10 feet below the top of the shallow aquifer (Ref. 9, p. 6). Intermediate wells are classified as $hose wells completed between 70 feet and 95 feet bgs and screened approximately 20 feet to 45 feet below the top of the shallow aquifer (Ref 9, p. 6). Deep wells are classified as those wells completed between 145 feet and' 155 feet bgs and screened approximately 1 00 feet below the top of the shallow aquifa (Ref 9, p. 6). Grouid water samples were collected fiom these monitoring wells between September and November" 1995 (Ref. ' 1 1, pp. 60 106). 8 , , .

1995 GROUND WATER INVESTIGATION RESULTS Hazardous Substance Concentration in ug/ L (PQL)

Perchloroethene 9,100 (100) 14,000 (100) 230 (5)

References Ref 1 1 , pp. 69 13 ; Ref. 4, p. Ref. 11, pp. 65 68; Ref. 4, p. 35; Ref. 11, pp. 60 64; Ref. 9, p. 2 1 ~ ~ ~~ ~ ~~~ ~~~~

Hazardous Substance Concentration in ug/ L (PQL)

Perchloroethene 1,300 (25) 510 (100)

Rdxz~~ ces Ref. 11, pp. 84 88; Ref 4. p. 35; Ref. 9, p. 30 Ref. 1 1 , pp. 74 78; Ref. 9, p. 28 Notes:

ug/ Lmicrograms per liter. PQLPracticalQuantitation Limit; usedfor comparison purposes by the lab since the sample was not analyzed through $e EPA CLP (Ref. 11, pp. 60 88).

HRS Documentation Record 05/ 30/ 01 30 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release 1995 GROUND WATER INVESTIGATION RESULTS (Continued)

Concentration in ug/ L (PQL)

37 .OO (1) 25,000 (1,000)

Ref11, pp. 94 97; Ref. Ref. 1 1 , pp. 98 101; 4, p. 35; Ref. 9, p. 32 Ref. 4, pp. 7,34,45 Notes: !,,,

ugL ' micrograms per liter. PQLPracticalQuantitationLimit; used for comparisonpurposes by the lab since the sample was not analyzed through the EPA CLP (Ref. :,,, . 11, pp. 89 106).

HRS Documentation Record 05/ 30/ 01 31 McGaEey and Main Groundwater Plume NM0000605386 GW ~

Likelihood of Release DECEMBER 1995 SAMPLING EVENT The 'ED95' series monitoring wells installed by the NMED were re sampled in December 1995 in an effort to continue to monitor the PCE contamination in the ground water (Ref. 1 1, pp. 107 130). Presented in the following tables are the analytical results fiom the ground water samples collected fromthe monitoring wells by the NMED in December 1995.

DECEMBER 1995 SAMPLING RESULTS I Hazardous Substance I Concentration in ug. L (§ DL)

Perchloroethene 1,400 (100) 15,000 (1,000)

References, I Ref. 11, pp. 113 114, 118; Ref. 4, p. 35; Ref. 9, Ref. 11, pp. 110 111, 115;, Ref. 4, p: 35; Ref. 9, p.

Hazardous Substance Concentration in ug/ L (SDL)

Perchloroethene 220 (5 ) 8,800 (200) 900 (50)

References Ref. 11, pp. 122 123, 127; Ref. Ref. 11, pp. 119 120, 124; Ref. Ref. 11, pp. 116 117; Ref. 4, p.

u g L micrograms per liter. §DL Sample Detection Limit; usedforcomparisonpurposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 11, pp. 107 124).

HRS Documentation Record 05130l01 32 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release DECEMBER 1995 SAMPLING RESULTS (Continued)

Hazardous Substance Concentration in ug/ L (SDL)

Percldoroethene 41 (1) 7,000 (200) 56 (1)

References Ref. 11, pp. 128 129; Ref. 4, p. Ref. 11, pp. 131 132,136; Ref. Ref. 11, pp. 125 126; Ref. 4, p.

HRS Documentation Record 05/ 30/ 01 33 McGafky and Main Groundwater Plume NM0000605386 GW  Likelihood of Release SEPTEMBER 1998 MONITORING WELL SAMPLING EVENT The NIvlED pdormed ground water sampling of the 'ED95' series monitoring wells again in September 1998 (Ref. 12, pp. 1 26). It should be noted that the monitorjng wells do not appear to have been sampled on a routine basis between the period of 1995 and 1998.

SEPTEMBER 1998 MONITOIUNG WELL RESULTS I a I I I Hazardous Substance , ., , , ?'

" ' Concentration in ug/ L (SDL) " ,

Perchloroethene 4,599 (100) 1,301 (100) 46.8 (1)

Referencff Ref. 12, pp. 1 2; Ref. 9,, p. 21 i ,, I ' , ' // , ,

Ref. 12, pp. 3 4 Ref. 4, p. 35; Ref. 12, pp. 3 Q Ref. 4, p. 35;

Hazardous Substance Concentration in ug/ L (SDL)

Perchloroethene 13,132.5 (250) 78.1 (20) 6,149 (1,000)

Refmces Ref. 12, pp. 1 1, 12; Ref. 4, p. Ref. 12, pp. 9 10; Ref. 4, p. 35; Ref. 12, pp. 1 8 ; Ref. 4, p. 35;

HRS Documentation Record 05/ 30/ 01 34 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release SEPTEMBER 1998 MONITORING WELL RESULTS (Continued)

N&

u g k . micrograms per liter. SDL Sample Detection Limit; used for comparison purposes by the lab since the sample was not ,analyzed through the EPA CLP (Ref. 12, pp. 13 26).

HRS Documentation Record 05/ 30/ 01 35 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MAY 1999 MONITORING WELL EVENT The Nh4ED performed ground water sampling ofthe 'ED95' series ofmonitoring wells again in May 1999 (Ref. 1 3, pp. 1 45). Based on the analytical results fiom these ground water samples, the presence of PCE continues to be detected in the same .monitoring wells.

MAY 1999 MONITORING WELL RESULTS Hazardous Substance Concentration in ug/ L (SDL)

Perchloroethene , ,, ,,

45.2 (1) ' ,, 1. ' ,, ' ' I 1,420 (50) ' ' 11 ;180 (200)

References Ref., 1,3, pp., 7: 9 Ref. 4, p. 35; RefU! 3, pp., 4 6; Ref. 4, p. 35; Ref. 13, pp. 1 3; Ref. 9, p. 21 , ,

, Ref. 'b. o. 24 Ref. 9 .:~. 23 , .. ., 8 , ,

.

Hazardous Substance , Concentration in ug/ L (SDL)

Perchloroethene . 4,100 (500) , )I 109 (40) . 690 ,( 20) '

References Ref. 13, pp. 16 18 ; Ref. 4, p. Ref. 13, pp. 13 15; Ref. 4, p. Ref. 13, pp. 10 12; Ref. 4, p. 35;

ug/ L micrograms per liter. SDL Sample Detection Limit; usedforcomparisonpurposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 13,

pp. 1 18).

HRS Documentation Record 05/ 30/ 01 36 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MAY 1999 MONITORING WELL RESULTS (Continued)

Ref. 13, pp. 22 24; Ref. 4, p. Ref. 13, pp. 25 27; Ref. 4, p.

ug/ L microgramsper liter. SDL Sample Detection Limil; used for comparison purposes by the lab since the, sample was not analyzed through the EPA CLP (Ref. 13, pp. 19 45).

HRS Documentation Record 05/ 30/ 01 37 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release APRIL 2000 SAMPLING EVENT The NMED conducted a sampling event m April 2000 inwhichboththe 'ED95' series monitoring wells, domestic wells, and irrigations wells were sampled (Ref 14, pp. 1 :72). The wells are located downgradient ofthe former dry cleaning facility. Well locations have been depicted I . on Figure A 3 of Attachment A.

APRIL 2000 DOMESTIC WELL aSULTS ,.

I , 4 , ,, ,

Hazardous Substance I ' : ., ' ,I , . ' Conceniration in ug/ L (SDL) II Perchloroethene 154 (5)

,*

Refer&=, Ref. 14, pp., 1 3; Ref. '4, p . 29, 79 Ref. 14, pp. 4 6; Ref., 4, pp. '28, 79 , ,.1 <' ,I ,

APRIL 200p I\; PONITO@ NG WELL RESULTS ., ~,

I *,. , 8 , , ..

,I I , 1. ,,",' , ,,i , . ,, 4 ' , ., ,

Notes: I !1 ., ug/ L micrograms per liter. SDL Sample Detection Limit; used for comparison purposes by the lab since the sample was not analyzed ,through the EPA CLP (Ref 14, pp. 1 15>. 1 8 ,

,.

I ,

HRS Documentation Record 05/ 30/ 01 38 McGaffey and Main Groundwater Plume NM000060.5386 GW  Likelihood of Release APRIL 2000 MONITORING WELL RESULTS (Continued)

Hazardous Substance Concentration in ug/ L'( SDL)

Perchloroethene I 1,928 (200)

I I Ref. 14, pp. 16 18; Ref. 4: p. 35; Ref. 9, p. 24 I Ref. 14, pp. 22 24 ; Ref. 4, p. 35; Ref. 9, p. 27 Ref. 14, pp. 34 36; Ref 4. p. 35; Ref. 14, pp. 37 39; Ref. 4, p. Ref. 14, pp. 40 42; Ref. 4, p.

Notes:

ug/ Lmicrogramsper liter. SDL Sample Detection Limit; usedfor comparison purposes by the lab since the sample was not analyzed through the EPACLP (Ref. 14, pp. 25 42).

HRS Documentation Record 05/ 30/ 01 39 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release APRIL 2000 MONITORING WELL RESULTS (Continued)

Hazardous Substance I. , Concenhation in ugiL (SDL)

Perchloroethene 5,270 (500) I '4,880 (500) ..

I R e f m m I Ref. 14; pp. 43 45; Ref. 4, pp. 7, 34, $5 Ref. 14, pp. 46 48; Ref. 4, pp. 7, 34 I , ' Hazardous Suhstance I Concentrdtion i n u d L (SDL) ,i I , , ,8 ~~~

Percuorckthene 671 (50) 9,520 (500) 158 (10)

References Ref. 14, pp. 49 51; Ref. 4, pp. 7, Ref. 14, pp. 55 57; Ref. 4, p. Ref. 14, pp. 52 54; Ref. 4, pp. . ,, ,

34 14 I. 34. 45 ,  ,I /

Notes:

ug/ L micrograms per, liter. SDL Sample Detection Limit; used for comparison purposes by the lab since the sample was not analyzed tbrobgh ' t h e E p A C L p (R e f . 14, ., ,

,I I pp. 43 57). ' I 'I ,.

HRS Documentation Record 05/ 30/ 01 40 McGaEey and Main Groundwater Plume NM0000605386 SEPTEMBER 2000 DOMESTIC WELL RESULTS GW  Likelihood of Release I Perchloroethene 97 (2' I I I References I Ref 14, pp. 67 69 Ref 4., p. 28 1 Ref. 14, pp. 70 72; Ref 4., p. 5 Notes:

ug/$ micrograms per liter. SDL Sample Detection Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 14, pp. 58 72).

HRS Documentation Record 05130101 41 McGaEey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MARCH 2001 SAMPLING EVENT The W E D conducted a ground water samplmg event m March 200 1 in which the 'ED95' series monitoring wells were sampled (Ref 15, pp. 1 48). These monitoring wells continue to exhibit contamination by PCE.

MARCH 2001 MONITORING WELL RESULTS Hazardous Substance Concentration in uglL (SDL)

Perchloroethene ,,

50.6 (10) 13,100 (100) 1 , ,. 910 (5)

I ~ ~~~ ~ ~

References I Ref. 15, pp. 1 3; Ref. 9: p. 21 I Ref. 15, pp. 476; Ref. 4, p. 35; 1' Ref. 15, pp. 7 9; lRef. 4, p. 35; I I Hazardous Substance I Concentration in udL (SDL) ' II I Perchloroethene 1,822 (100) 3,100 (20)

II I Ref. 15, pp. 10 12; Ref. 4, p. 35; Ref. 9, p. 24 Ref 15, pp 16 18; Ref. 4, p. 35; Ref. 9, p. 27 ug/ L micrograms per liter. SDL Sample Detection Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 1.5, pp. 1 18).

HRS Documentation Record 05/ 30/ 01 42 McGaEey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MARCH 2001 MONITORING WELL RESULTS (Continued)

Ref. 15, pp. 31 33: Ref. 4, p.

Ref. 15, pp. 40 42;

ug/ L micrograms per liter. SDL Sample Detection Limit; used for comparison puposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 15, pp. 19 48).

HRS Documentation Record 05/ 30/ 01 43 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MUNICIPAL SUPPLY WELL INVESTIGATION The City of Roswell has four contaminated municipal supply wells located withip a 4 mile radius of the former dry cleaning facility: SRW12, SRW13, SRW15, and SRWl6 (Ref. 21, pp. 1 6). These four wells are active municipal supply wells for the City of Roswell, which proyide drinking water to the residents of Roswell. All of the City of Roswell municipal supply wells obtain their water fi om the carbonate rock (artesian) aquifer, which is'hydraulicdy connected to the shallow alluvih aquifer (Ref. 19, p. 10; Ref. 21, p. 1). Further, the carbonate, rock (artesian) aquifer and the hydraulically comiected alluvial aquifer together comprise the Roswell Basin Aquifer system. This system has been designated as a karst aquifer by the USGS (Ref 19, p. 1, O). 1 .,

. ,,

. ._ > .. .I .

,I PCE has been detected intermittently mmunicipal'supply wells SRW12 and SRW 13 since 1995. PCE has been deteeted consistently m municipal supply wells SRW 15 and SRW 16 since 1993. However, the concentrations of PCE detected in the municipal supply wells' h& e been below the F, ederalMCL of 5 ug/ L for PCE. ' Under the Federal SDWA, no treatment is r e q ~e d utitil the'MCL is reached {Ref. 4, p. 5). " I. , i I ,,

I ,.

A discussion of the municipal supply well chosen to represent background conditions, SRWl7, is presented in Section 3.1.1 (Observed Release, Background Domestic Wells) of this documentation record. Ground water samples were collected from municipal supply well SRW17 between the years of 1992 aqd :1999 (Ref. 17, pp. 3 1 3 7). Concen& ti& s of PCE have not been detected, $I any of +e b u n d water samples collected. Thus, the background levels for the municipal supply wells e c h are completed m the carbonate rock (artesian) , aquifer is considered to be non detect. , 'I I , , . , ., 10%

, P '

, ii: , ,

HRS Documentation Record 05/ 30/ 01 44 McGaffey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release MUNICIPAL SUPPLY WELL ANALYTICAL RESULTS  Notes:

ugiL micrograms per liter. PQL Practical Quantitation Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref.

MDL Method Detection Limit; usedfor comparison purposes by the lab since the sample was not analyzed through the EPA CLP (Ref. 17,

SDL Sample Detection Limit; used for comparison purposes by the lab since the sample w a not analyzed through the EPA CLP (Ref. 17, 17, pp. 1,7, and 14).

pp. 2 3, 6, 8 9, 12 13, 5 , and 18 21).

pp. 4 5, 10 11, and 16 17).

HRS Documentation Record 05/ 30/ 01 45 McGaffey and Main Groundwater Plume NMOO00605386 GW  Likelihood of Release MUNICIPAL SUPPLY WELL ANALYTICAL RESULTS (Continued)

 Notes: .I u g L micrograms per liter. , ' I PQL F'ractical Quantitation Limit; used for comparison purposes by the lab since the sample was not analyzed through the qPA CLP (Ref.

MDL Method Detection, Limit; used for comparison purposes by the lab since the sample was not analyzed through the EPA; CLP (Ref. 17,

SDL Sample Detection Limit; used, for comparison purposes by the lab since the sample was not analyzed through 'the EPA CLP (Ref. 17, 17, p. 24).

pp. 22 23, 25, and 28 30). ' , ' I I pp. 26 27).

HRS Documentation Record os/ 30/ 01 46 McGalTey and Main Groundwater Plume NM0000605386 GW  Likelihood of Release Attribution The McGaffey and Main Ground Water Plume site i$ located in Roswell, Chaves County, New Mexico near the intersectionof South Main Street and McGaffey Street. The site is located in an area ofmixed commercialand industrialuse. Residential areas are located M e r south of the site. Essentially, there is no open or undeveloped land within the immediate vicinity of the site (Ref. 3 , pp. 1 3). Perchloroethylene (PCE) contaminationhas been identified throughout the alluvial aquifer as a ground water plume that extends from beneath the intersection of McGaffey and Main in a southeasterly direction (Ref 4, p. 3).

Theboundaryofthegroundwaterplume is definedbygroundwatersamplescollectedf? omdomestic, monitoring, and municipal supply wells. The precise extent ofthe plume has not yet been identified, but appears to measure approximately one mile in length. As such, only one ground water plume has been considered for the purposes of this documentation record since the contaminants identified wih the ground water wells are the same. There are at least three other ground water plumes in the Roswell Bash'however, it is not known at this time if these plumes are commingled (Ref. 6, p. 3; Ref 8, p. 2).

The NMED has been the primary agency involved in the investigation of this groid water plume. The NMED discovered the ground water plume inNovember 1 994 following the investigation of a leaky underground storage tank at the ,former Pepsi Cola bottling plant. Ground water samples collected fiom monitoring wells installed as part of the investigation conducted at the former bottling plant revealed the presence of high concentrations of PCEand gasoline constituents. The highest concentrations ofPCE were observed across South Main Street fiom the former bot@ ng plant, in an area referred to as Highland Center (Ref 4, p. 3). ". ..

8 ,

The source of the ground water contamination is unidentified However, there are several potential sources of the contamination m the area. Previous studies have indicated that operations at the former Lee Mack dry cleaning fxility may have contxibuted to the ground water plume, 'but no specific sources at the former facility property have been identified (Ref 4, p. 3;, Ref 5 , p. 1). Extremely high concentrations of PCE have been detected in a monitoring well located approximately 40 feet southeast of the former dry cleaning facility suggest that past disposal practices at the dry cleaning facility may have including discharging waste PCE behind the facility (Ref. 6, p. 1). PCE has been detected in this well at concentrations up to 25,000 micrograms per liter (ugiL) (Ref 5, p. 1; Ref. 6, p. 1). During a site investigation in 1994, following a review of the locations of the PCE plume and the local dry cleaning facilities, it appeared that the PCE contamination could be a result of PCE discharges to the sewer line locationman alley east o f W Street (Ref. 20, pp. 5 6). Possible leakage of these sewer lines could have contributed to the discharge ofthe PCE to the subsurface ground water (Ref 4, p. 3; Ref 6, p. 1; Ref. 20, p. 6). In addition to Lee Mack Cleaners, there are at least six other dry cleaning facilities which operated m the area at some time m addition to several auto service facilities which may have also used chlorinated solvents (Ref. 4, p. 52 54, Ref. 20, p. 4).

HRS Documentation Record 05/ 30/ 01 47 McGafTey and Main Groundwater Plume NM0000605386 GW  Waste Characteristics The NMED has conducted several soil and ground water investigations in the area, however, the precise extent %ofthe PCE contaminationm the ground water has not yet been determined. PCE is a manufactured product and the primary solvent used in commercial and industrial dry cleaning (Ref 22, p. 1). PCE is not ubiquitous or naturally occurring within the environment.

3.1.2 Potential to Release  Not Scored According to the HRS Rule, potential to release is only scored if an observed release cannot be established for the aquifer of concern (Ref I, Sec. 3.1.2). As such, the Potential to Release for the ground water migration pathway was not evaluated because an observed release has been documented for the Roswell and 5th Street Ground Water Plume site (Ref 1, Sec. 3.1.1).

3.2 WASTECHARACTERISTICS The waste characteristics factor category for an aquifer is evaluated based on two factors: toxicity/ mobility and hazardous waste quantity. Only those hazardous substances that are mailable to the ground water migration pathway canbe considered (Ref, 1, Sec. 3.2). PCE is the only hazardous substance that is considered available to the ground water migration pathway for this site. A discussion of each separate factor value is presented in the following subsections. ,Factor values for toxicity and mobility are presentedcin the following table.= well as calculations for the combined toxicityhnobility. .,

Notes:

' Value assigned using the Superfind Chemical Data Matrix (Ref. 2). A mobility factor value of 1 is assigned'since perchloroethylene meets the criteria for an observed release to ground water (Ref. 1 , Sect. <IP_ADDRESS>).

HRS Documentation Record 05/ 30/ 01 48 McGaffey and Main Groundwater Plume NM0000605386 GW  Waste Characteristics 3.2.1 ToxicityMobility <IP_ADDRESS> Toxicity According to the HRS Rule, toxicity is evaluated for those hazardous substances at the site that are available to a pathway being scored (Ref 1, Sec. <IP_ADDRESS>). Toxicity values for hazardous substances are assigned in the SuperfundChemicalDataMatrix( SCDM) andhavebeenpresented in atable in Section3.2of this documentation record (Ref. 2).

<IP_ADDRESS> Acdording to the HRS Rule, for any hazardous substance that meets the criteria for an observed release by chemical Bnalysis to one or more aquifers underlying the source( s) at the site, regardless of the aquifer being evaluated, a mobility factor value of 1 is assigned (Ref 1, Sec. <IP_ADDRESS>).

3.2.2 Hazardous Waste quantity AccOrding to &e HRS Rule, for all migrationpathwayshazardousconstituentquantityisnotadequately determined adifany Level1 or Level11 concentrations are present for the pathway being evaluated, thena value of 100 is assigned as the hazardous waste quanti6 factor value forthatpathway( Ref 1 , Sec. <IP_ADDRESS>). As swh, since the= are targets which are subject to Level I and, Level II concentrations, a pathway hazardous waste q& tity factor value of 100 is assigned.

Pathway Hamdous Waste Quantity Factor Value: 100 3.2.3WasteCharacteristicsFactorCategoryValue According to the HRS Rule, the waste characteristics factor category value is derived by multiplying the toxicity/ mobility factor value by the hazardous waste quantity factor value (Ref. 1, Sec. 3.2.3). Based on this product, a value from Table 2 7 of the HRS Rule is assigned to the waste characteristics factor category (Ref 1, Sec. 3.2.3). ' '

The toxicity/ mobility factor value of 100 multiplied by the hazardous waste quantity factor value of 100 equals a product of 10,000. According to Table 2 7 of the HRS Rule, a product of 10,000 equates to a waste characteristics factor category value of 10 (Ref. 1 , Table 2 7). ,,

ToxicityMobGity Factor Value (100) x Hazardous Waste Quantily Factor Value \loo): 10,000 Waste Characteristics Factor Value: 10 HRS Documentation Record 05/ 30/ 01 49 McGaffey and Main Groundwater Plume NM0000605386 GW  Targets 3.3 TARGETS ,.

The City of Roswell is located in the northern portion of the Roswell Ground Water Basin., Large volumes of ground water are withdrawn &om a shallow alluvial aquifer and underlying carbonate rock (artesian) aquifer in the Roswell Basin. The carbonate rock aquifer and the hydraulically connected aquifer inthe alluvium form the Roswell Basin Aslllfer system, whichis the aquifa systembeingwaluated for this site. (Ref. 19, p. 10). Further, the aqdiers of the Roswell Ground Water Bas@ have been classified as karst aquifers by the USGS (Ref. 19, p. 10).

Because of the dissolution cavities and the channels that comprise thq karst aquifers are considered extremely vulnerable to contamination. Themovementofhazardoussubstancesreleasedintokarstaquifersishighly unpredictable, and transport over relatively long distances caq occur very rapidly (Ref 10, p. 4). The City of Roswell's primary chinking water supply resides mthe carbonate rock (artesian) aquifer and the municipal supply wells are completed within the carbonate rock (@ esianj ., aquifer (Ref. 2 1, p. 1).

Interaquifkr leakage occurs between the alluvial aquser and the carbonate rock (artesian) aquifer through the Queen aquitard (1 8, p. 8). Leakage is generally greatest in the vicinity of Roswell. Prior to $e development of . irrigationwells, water leaked vertically upward fiomthe carbonate aquifer to the alluvial aquifer. At present, the large drawdown of the potentiometric surface m the dFQonate rock aquifer during the summer irrigation season reverses the direction of vertical leakage (i. e., le& ge 6 downward @om the alluvial W e r into the carbonate rockaquifer) ( Ref. 18, pp. 8 9j. .

The City of Roswell municipal supply system is composed of 20 municipal supply wells that are coppleted within the carbonate rock (artesian) aquifer. According to the City of Roswell municipal supply systtkn manager, none ofthe 20 municipalwells contribute more than40 percent of the overall production. Further, various wells serve as standby wells on a rotating basis (Ref 2 1 ,' p. 1 ). ' Based on information provided by the City of Roswell, there are 4 City of Roswell municipal supply wells located Within a 4 mile radius of the ground water plume in which PCE has been detected (Refs. 12; 13; 15; 16; 17; 21; pp. 1 $.

During the Nh4ED's 1995 Domestic Well investigation, t h r ~ residences were discovered whose sole source of water (including drinking) was fi om their domestic wdls which are completed m the shallow alluvial a q ~e r . PCE was detected in two of the three wells at concentrations of 79 ugL and 105 uglL (Ref 6, p. 3 j. The, NMED provided emergency funding to connect these residences to the City of Roswell systemwhichreceives its water fromadeepercarbonate rock( artesian) aquifer( Ref 7, p. 1; Ref 8, p. 1). .,

Target wells identified forthis site consist of municipal supply wells aqd domestic wells that lie within the Target Distance Limit (TDL) of a &mile radius from the estimated center ofthe plume. Target wells identified within the TDL have been presented in the table below. ,Well locations yithin each distance radii are .depicted on Figure A 3 of Attachment A (Ref 21, pp. 1 6): 'It should be noted that the approximate boundary of the estimated extent ofthe ground water plume was defined based on ground water samples meeting observed release criteria. ,.

HRS Documentation Record 05/ 30101 50 McGaffey and Main Groundwater Plume NM0000605386 GW ~

Targets The distances from the source were measured from the former dry cleaning facility as it is considered to be a potential source of the ground water plume.

TARGET WELLS 3.3.1 Nearest Well According to the HRS Rule, if one or more drinking water wellsis subject to Level I concentrations, a value of 50 is assigned as the Nearest Well Factor Value (Ref 1, Sec. 3.3.1). As such, the two private domestic wells are subject to Level I concentrations and were being used as the sole source of drinking water for the residences at the time the PCE was detected (Ref 4, p. 5). These wells are located within a 2 mile radius of the former dry cleaning facility which is considered to be the source of the PCE contamination (See Figure A 3). In 1995, the NMED provided emergency h d m g to connect these residences to the City of Roswell system which receives its water fiom a deeper carbonate rock (artesian) aquifer (Ref. 4, p. 5; Ref. 8, p. 1). These wells remain available for sampling, but are no longer used for drinking water purposes. As such, a value of 50 has been assigned as the Nearest $ell Factor.

Nearest Well Factor: 50 3.3.2 Population A discussion ofthe population served by drinking water wells (i. e., municipal supply wells afid private domestic wells) located within the established TDL is presented in the following subsections.

HRS Documentation Record 05/ 30/ 01 51 McGaffey and Main Groundwater Plume NM0000605386 GW  Targets <IP_ADDRESS> Level of Contamination <IP_ADDRESS> Level I Concentrations Level I concentrations are established m samples from drinking water wells in which the concentration of a hazardous substance that meets the criteria for an observed release is at or above its drinking water benchmark (Ref. 1, Sec. 2.5). Drinking water benchmarks, as set forth in SCDM, include Maximum C o n d t Level (MCL) and/ or screening concentrations for cancer risk (Ref 2).

Level I concentrations have been documented in two private domestic wells in accordance with the HRS Rule (Ref. 1, Sec. <IP_ADDRESS>). During the NMED's 1995 investiiationofdomestic wells withinthe, vicinityofthe foker dry cleaning facility, three residences were discovered wliose sole source of drinking water was provided fi om their domestic wells. Concentmtions of PCE, were detected in two of the three domestic wells at concentrations of 79 ug/ L and 105 ugL which exceeded the MCL for PCE of 5 ugL (Ref 6, p. 3). In 1995; the NMED provided emergency funding to connect thes&.. residences tb &, City of Roswell system which receives its water from a deeper carbonate rock (artesian) aquifer (Ref. 8, p. 1). These wells remain available for sampling, but arenolongerusedfordrinking water purposes( Ref. 4, p. 5). I , I 8, ,,. . I Since these domestic wells were being used. a s . drinking water wells at the time the PCE contamination was discovered, they will be considered subject t i 1 contamination (Ref 8, p. 1).

Level I concentmtions documented in pundl water samples collected &om the private domestic wells are presented in the following table. The locations of the private 2omestic wells are depicted on Figure A 3 of Attachment A. The domestic wells are located within a 2 mile radius of the former dry cleaning facility.

LEVEL I CONCENTRATIONS I' I 2305 S. Cahood Ref. 2; Ref. 11, pp. 11 MCL 79 5 PCB 01/ 30/ 95 1706 S. Atkinsod IO OR 95 0628 Ref. 2; Ref. 11, pp. 6 MCL 5 105 PCE 01/ 27/ 95 Note:

* Value assigned using the Superfund Chemical Data Matrix (Ref. 2).

According to the 2000 Census Population, there are approximately 2.66 persons per household Cx Chaves County @ef 23, p. 2). Thus, 2.66 will be assigned as the approximate number ofpersons served by each well (Ref. 1, Sec. 3.3.2).

HRS Documentation Record 05130101 52 McGatTey and Main Groundwater Plume NM0000605386 GW  Targets According to the HRS Rule, the Level1 ConcentrationFactor Value is calculated by i d e n m g the wells subject to Level I concentrations and summing the number of people served by these wells. This sum is then multiplied by 10 and the resulting product is assigned as the Level I Concentration Factor Value (Ref 1, Sec. <IP_ADDRESS>).

' LEVEL I POPULATION 2305 S. Cahoon Ref. 23, p. 2 2.66 1106 S. Atkinson Ref. 23, p. 2 2.66 Population Served by Level I Wells: 2.66 x 2 = 5.32 Level I Concentration Factor Value: 5.32 x 10 = 53.2 <IP_ADDRESS> Level I1 Concentrations Level I1 concentrations are established m samples from drinking water wells in which the concentration of a hazardous substance meets the criteria for an observed release, but is less than its drinking water benchmark (Ref. 1 Sec. 2.5). Drinking water benchads, as set forthm SCDM, include MCLs and/ or screening concentrations for cancer risk (Ref. 2).

Level I1 concentrations have been documented in City of Roswell municipal supply wells SRW12, SRWl3, SRW15, and SRW16onseveraloccasions maccordancewiththeHRS Rule (Ref. I, Sec. <IP_ADDRESS>; Ref. 17, pp. 1 27). Ground water samples collected as part of routine compliance sampling have established Level 11 concentrations in these municipal supply wells. The highest LevelII concentration documented in ground water samples collected fromthe four aforementioned municipal supply wells are presented m the following table. Well locations are depicted on Figure A 3 of Attachment A.

HRS Documentation Record 05/ 30/ 01 53 McGaffey and Main Groundwater Rume NM0000605386 GW  Targets LEVEL II CONCENTRATIONS ..

* Value assigned using the Superfund Chemical Data Matrix (Ref. 2)

Municipal supply wells SRW12, SRW13, SRW1.5, and SRW16 are active wells that are part of the blended system providing drinking water to the City of Roswell. The City of Roswell municipal supply system is composed of 20 municipal supply wells, none of which contribute more than 40 percent of the overall total production oithe system (Ref 21, p. 1). The system serves approximately 17,500 connections; or a population of approdatey 48,000 inckiduals (Ref 21, p. '1).

Because no one municipal supply well contributes more than40 percent ofthe o v e d total production ofthe City ofRoswell system the total number of individuals served by the system will be apportioned equally to each well (Ref 1, Sec. 3.3.2; Ref 21, p. 1). Thus, approximately 2,400 individuals are served by each well and this number will be assigned as the population associated with mmkipal supply wells SRW12, SRW13, SRWl5, and SRWl6 (Ref. 1, Sec. 3.3.2; Ref. 2 1 , p. l)." ' ..

48,000 individuald20 municipal supply wells = 2,400 individuals per well According to the HRS Rule, the Level11 ConcentrationFactor Value is calculated by identdjmgthe wells subject to Level II concentrations for the aquifer being evaluated and summirig the number of people served by these wells. This product is assigned as the Level I1 Concent& on Factor Value (Ref 1, Sec. <IP_ADDRESS>).

HRS Documentation Record 05/ 30/ 01 McGaffey and Main Groundwater Plume NM0000605386 54 GW  Ground Water Migration Score for an Aquifer GW  Ground Water Pathway Score LEVEL I1 POPULATION I SRW16 I 2,400 Ref. 1, Sec. <IP_ADDRESS>; Ref. 21, p. 1 I Population Served by Level 11 Wells: 2,400 x 4 = 9,600 Level 11 Concentration Factor Value: 9,600 <IP_ADDRESS> I . PotentialContamination Even tho@ the potential exists for the remaining City of Roswell municipal supply wells to be subject to cm*@ mination by PCE, potential contamination will not be evaluated because actual contamination has already been documented for both domestic wells and municipal supply wells for the McGaffey and Main Groundwater Plume site.

3.3.3 Resources Water drawn fhm any target well for the aquifer being evaluated that is used for irrigation of commercial food crops or commercial forage crops can be considered a resource under the HRS Rule (Ref 1 , Sec. 3.3.3). The City of Roswell is a large agriculture area (Ref 6, p. 1). In 1978, approximately 95 percent ofthe ground water withdrawn from the Roswell basin was used for irrigation. In 1985, approximately 88 percent of the ground water witldrawn fiom the Roswell basin was used for irrigation (Ref. 19, p. 1 6). As such, a Resources Factor Value of 5 will be assigned (Ref 1, Sec. 3.3.3). Resources Factor Value: 5 3.3.4 WellheadProtectionAreas A Wellhead Protection Area (WHPA) is defined as the area designated by states according to Section 1428 of the Safe Drinking Water Act (SDWA), as amended, to protect wells and recharge areas that supply public drinking water systems (Ref. 24, pp. 1 2).

For the State ofNew Mexico, a radius of 1,000 feet has been designated as a WHPA around all municipal supply wells (Ref 24, pp . 1 2). Four municipal supply ells displaying Level 11 concentrations are located within a 4 mile radius of the approximate extent of the ground water plume. Since obsemed ground water contamination attributable to sources at the site lies partially or M y within the designated Wellhead Protection Area, a Wellhead Protection Factor Value of 20 will be assigned (Ref, 1, Sec. 3.3.4).

HRS Documentation Record 05/ 30/ 01 55 Wellhead Protection Area Factor Value: 20 McGafSey and Main Groundwater Plume NM0000605386 GW  Ground Water Migration Score for an Aquifer GW  Ground Water Pathway Score 3.4 GROUNDWATER MIGRATION SCORE FOR AN AQUIFER The carbonate rock (artesian) aquifer and the hydraulically connected aquifer m the alluvium form the Roswell Basin Aquifer system, which is the quifa being evaluated for this site (Ref. 19, p. 10). The ground water migration score for the q& er, being evaluated was calculated as follows:

Score = LikelihoodofRelease x WasteCharacteristics x Targets/ 82,500   550 x 10 x 9678,2/ 82,500   645.21 According to the HRS Rule, the ground water migration score for an aquifer is subject to a maximumvalue of 100 (Ref 1, Sec. 3.4). As such, a value of 100 will de &signed as the gound water migration score for an aquifer.

Graund 'Mj'ater Migration Score for an Aquifer: 100 3.5 &

A value of 100 is assigned as the ground water migration pathway score since only one aquifer was evaluated for the site (Ref. 1, Sec. 3.5).

Ground Water Migration Pathway Score: 100 HRS Documentation Record 05/ 30/ 01 McGatTey and Main Groundwater Plume NM0000605386 Surface Water  Not Scored 4.0 SURFACEWATERMIGRATIONPATHWAYSCORE  NOT SCORED The surface water migration pathway will not be scored because it is not expected to contribute sigmficantly to the overall site score. Further, the site score exceeds 28.5 based only on evalution of the ground water pathway.

HRS Documentation Record 05/ 30/ 01 57 McGaEey and Main Groundwater Plume NM0000605386 5.0 SOIL EXPOSURE  NOT SCORED Soil Exposure  Not Scored Soil exposure will not be scored because it is not expected to contribute sigmficantly to the overall site score. Further, the site score exceeds 28.5 based only on the evaluation of the ground water pathway.

HRS Documentation Record 05/ 30/ 0 1 58 j McGaffey and Main Groundwater Plume NM0000605386 Air Pathway  Not Scored 6.0 AIR MIGRATIONPATHWAY  NOT SCORED HRS Documentation Record 05/ 30/ 01 59 McGaffey and Main Groundwater Plume NM0000605386 t N I Reed Street T I : Former Dry Cleaners (D + TH 7A + TH 8A ED95 5 * + ED95 8 ED95 13 +

D95 4 095 3 095 2 McGaffey Street ED95  7 LEGEND i Shallow Well * tntermediate Well + DeepWell e" ' Vapor Well @ 900 Fort Street Moll Suite 810 Honolulu, Howoii 96813 (808) 585 0448 ' IO0 feet I MONITORINGWELLLOCATIONMAP FIGURE Roswell ' Chaves Countv. NewMexico I A 2 I I

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