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<br /> 'BLE 1 -CHECKLIST OF REQUIRED DATA r...
<br /> FOR NO FUR i%,,oR ACTION REQUESTS AT UNDER'GROUND,,fNK SITES
<br /> Site Name and Location: Enterprise Investments(AKA J&13 Murphy Trucking), 355 Enterprise Place Tracy, San Joaquin
<br />! County(Lustis Case 390986) i
<br /> Y Distance to production wells for municipal, domestic, A 2001 well survey reported 4 domestic wells located 1,500,
<br /> culture, indust and other uses within 2000 feet of the site. 1,550', and!1,600'southwest and 1,400'west of the site.
<br /> Y 2. Site maps, to scale, of area impacted showing locations One 10,000,-gallon diesel UST and associated piping were i
<br /> of any fonner and existing tank systems; excavation removed 8/97. TPHg, TPHd, ethylbenzene and xylenes were
<br /> contours and sample locations, boring and monitoring well detected in soil beneath the USTs. No new USTs were
<br /> elevation contours, gradients, and nearby surface waters, installed. ;6
<br /> buildings, streets, and subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment Site lithology consists of clay, silt,and sand to
<br /> system diagrams; 35 feet, theltotal depth investigated.
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the excavated soil is not discussed in the
<br /> re arts.
<br /> y 5. Monitoring wells remaining on-site, fate; Five monitoring wells(MW-1 through MW-5)and one extraction well(EW-1)
<br /> remainingon-site will be Loperly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater,varied from 6 to 12 feet below ground surface
<br /> elevations and depths to water, (logs). The groundwater gradient varied from 0.001 to 0.005 ft/ft,and the
<br /> down radient direction varied in all directions.
<br /> 7. Tabulated results of all sampling Maximum confirmation (8/97)sample soil concentrations were TPHg, 160 mg/kg;
<br /> and analyses: TPHd, 4,.200 mg/kg;ethylbenzene, 0.01 mg/kg;and xylenes, 0.041 mg/kg.
<br /> Y Detection limits for confirmation Soil after boring results(8/07) we
<br /> ❑ re TPHg, 90 mg/kg; TPHd, 3,900 mg/kg. Maximum
<br /> grab groundwater concentration's(7/00) were TPHg, 2,100 ug/L; TPHd, 2,900,000
<br /> sampling ug/L;benzene, 38 ug/L;toluene,112 ug/L;ethylbenzene,53 ug/L;xylenes, 68 ug/L;
<br /> and MtBE;8.2,ug/L. In 2/08, all groundwater monitoring sample results were non-
<br /> 0 Lead analyses detect and have remained non-detect since 2/07.
<br /> 8. Concentration contours of contaminants.found and those remaining in soil and The extent of the identified
<br /> groundwater, and both on-site and off-site: rcontamination shown in applicable
<br /> reports.
<br /> ❑Lateral and ❑Vertical extent of soil contamination
<br /> Lateral and Vertical extent of roundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation The regulatory agency did not require an
<br /> system and the zone of capture attained for the soil and groundwater remediation engineered remediation.
<br /> system; !
<br /> 10.Reports/inforrnation ❑Y Unauthorized Release Form ❑Y QMRs(22 from 2102 to 2108)
<br /> I
<br /> ❑ Well and boring logs ❑ PAR R FRP ❑ Other;Closure Summary,1104;Additional Site Investigation,
<br /> 9107
<br /> Y 1 11.Best Available Technology(BAT) used or an explanation for not using Removal of USTs,and natural attenuation.
<br /> BAT
<br /> U12. Reasons why background was/is unattainable Limited soil contamination remains on-site.
<br /> BA T; j
<br /> 73' sa�ascalc � re =
<br /> Theonsultant,estimated_approximately1,500_g _of.residual-of-residual-
<br /> :yl] sbcelatio ofsubstanceYWW sr
<br /> TPHd contamination in soil.
<br /> versus that remaining, ,�
<br /> Y 14. Assumptions, parameters, calculations and No soil vapor ESLs Were exceeded during the soil vapor analyses,as
<br /> model used in risk assessments, and fate and all analyses were non-detect. A fate and transport model did not
<br /> transport modelin show impacts in groundwater at 165 feet from USTs.
<br /> I, 15. Rationale why conditions remaining at site will Soil contamination is limited in extent. Results of 22 quarters of
<br /> not adversely impact water quality, health, or other groundwater monitoring show a decreasing trend in concentrations to
<br /> beneficial uses;and non-detect. WQOs have been reached.
<br /> By: JLB Comments: One 10,000-gallon diesel UST and associated piping were removed 8/97 at the subject site. TPHg,
<br /> TPHd, ethylbenzene and xylenes were detected in soil beneath the USTs. No new USTs were installed.
<br /> Date: Maximum confirmation(8/97)sample soil concentrations we're TPHg, 160 mg/kg; TPHd,4,200 mg/kg;
<br /> 8/1512008 ethylbenzene, 0.01 mg/kg;and xylenes, 0.041 mg/kg. Soil after boring results(8/07) were TPHg, 90 mg/kg;
<br /> TPHd, 3,900 mg/kg. Maximum grab groundwater concentrations(7/00) were TPHg, 2,100 ug/L; TPHd, 2,900,000
<br /> ug/L;benzene, 38 ug/L;toluene, 12 ug1L;ethylbenzene, 53 ug/L;xylenes, 68 ug/L;and MtBE,8.21rg/L. In 2/08,
<br /> all groundwater monitoring sample results were non-detect, and have remained non-detect since 2/07. Based
<br /> upon 22 quarters of declining groundwater concentrations to ND, no exceedence of ESLs in soil for residual
<br /> contamination, the lack of threat from vapor intrusion, no anticipated threats to sensitive receptors, and the
<br /> limited extent of contamination present in soil, Regional Boaid staff concur with San Joaquin County's
<br /> Closure Recommendation. ;
<br /> )
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