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J'SLE 1 -CHECKLIST OF REQUIRED DATA fi
<br /> FOR NO FURT�.� ACTION REQUESTS AT UNDERGROUND,NK SITES
<br /> Site Name and Location: USA Petroleum, 2500 W. Lodi Ave., Lodi, San Joaquin County(Case 390096)
<br /> VDistance to production wells for municipal, domestic, A 2008 well survey reported no supply wells and 2 domestic
<br /> culture, industry and other uses within 2000 feet of the site. wells within 2000'of the site, one at 1000'south,and one at
<br /> 1000'northeast.
<br /> Y 2. Site maps, to scale, of area impacted showing locations Three 12,000-gallon gasoline USTs and associa#ed piping
<br /> of any former and existing tank systems, excavation were removed and replaced 10/97. TPHg, benzene, toluene, I
<br /> contours and sample locations, boring and monitoring well ethylbenzene,xylenes, and MTBE were detected in soil r
<br /> elevation contours, gradients, and nearby surface waters, beneath the USTs. k
<br /> buildings, streets, and subsurface utilities;
<br /> ::Y1 3. Figures depicting lithology(cross section), treatment Site lithology consists of clay, silt, and sand to
<br /> system diagrams; 60 feet, the total depth investigated.
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 500 cubic yards bf excavated soll was
<br /> transported to Forward Landfill in Manteca.
<br /> y 5. Monitoring wells remaining on-site, fate; Eleven monitoring wells(MW-1 through MW-4, MW-6 through MW-10, S-1, r
<br /> and S-2)and two remediation wells(VW-1 and AS-1)remaining on-site will
<br /> be pMerly abandoned.
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<br /> Depth to groundwater varied from 35 to 48 feet below ground surface(bgs).
<br /> 6. Tabulated results of all groundwater
<br /> elevations and depths to water The groundwater gradient varied from 0.001 to 0.003. The downgradient
<br /> groundwater flow direction varied from south to southeast.
<br /> - 7.---Tabala7ed`results of-all'sarnpling:--Maximum confirmation soil-concentrations-(10/97-)-were-TPHg;-8,400-mg/kg;-- --
<br /> and analyses: benzene, 15 mg/kg;toluene, 150 mg/kg;ethylbenzene, 100 mg/kg;xylenes,
<br /> 750 mg/kg, and MTBE, 23 mg/kg. In 6106,soil boring after results(post
<br /> Detection limits for confirmation remediation)were ND. Maximum groundwater monitoring concentrations(6/99)
<br /> sampling were TPHg, 15,000 ug/L;benzene, 120 ug/L;ethylbenzene, 270 ug/L;xylenes,
<br /> 1,200 ug/L;and MTBE; 15,000 Erg/L. In 5/08,groundwater monitoring i
<br /> []Y Lead�analyses concentrations were ND. v
<br /> ETLF8. 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: contamination shown in applicable
<br /> reports.
<br /> Y❑Lateral and Y❑Vertical extent of soil contamination
<br /> Latera!and Vertical extent of groundwater contamination
<br /> 9, Zone of influence calculated and assumptions used for subsurface remediation Over-excavation, SVE/AS, and dual
<br /> system and the zone of capture attained for the soil and groundwater remediation phase extraction(DPE) were the
<br /> system; required engineered remediation.
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑y QMRs(38 from 12198 to 7108) I
<br /> Well and boring logs rV_j PAR � Other;No Further Action Request 8/08
<br /> FRP
<br /> Y 1 11,Best Available Technology(BAT) used or an explanation for not using BAT; Removal of USTs, aver-excavation,
<br /> SVE/AS, DPE,and natural attenuation.
<br /> 2. Reasons whybackground wads unattainable usingBAT, Limited soil contamination remains on-site.
<br /> ii-113.Mass balance calculation of substance treated versus that The consultant did not estimate contamination treated
<br /> and contamination remaining in soil.
<br /> remainin ;
<br />- - r after -in.
<br /> Y "14. A'ssurirptioFms;parameters;calcatations�and•modelused rn. Ao-sor!-vapor-contamma#ron-was-was -detected _ _ -- i
<br /> risk assessments, and fate and transport modeling; 2006 and after DPE in 2008. The site is an active service !
<br /> station.
<br /> Y 15. Rationale why conditions remaining at site will not adversely Soil contamination is limited in extent and not leaching to
<br /> impact water quality, health, or other beneficial uses;and groundwater. Results of 38 quarters of groundwater
<br /> monitoring show a decreasing trend in concentrations to
<br /> ND.
<br /> By: JLe Comments: Three 12,000-gallon gasoline USTs and associated piping were removed and replaced 10/97.
<br /> Sa Maximum confirmation soil concentrations(10/97) were TPHg, 8,400 mg/kg;benzene, 15 mg/kg;toluene,
<br /> Date: 150 mg/kg;ethylbenzene, 100 mg/kg;xylenes, 750 mg/kg, and MTBE, 23 mg/kg. In 6106,soil boring after
<br /> 12/1812008 results(post remediation)were ND. Maximum groundwater monitoring concentrations(6199)were TPHg,
<br /> 15,000 ug/L;benzene, 120 ug/L;ethylbenzene, 270 ug/L;xylenes, 1,200 ug/L;and MTBE; 15,000 Erg/L. In 5/08,
<br /> groundwater monitoring concentrations were ND. Based upon 38 quarters of declining groundwater
<br /> concentrations to NO,no reported threat from vapor intrusion,no anticipated threats to sensitive receptors,
<br /> and the limited extent of contamination present in soil,Regional Board staff concur with San Joaquin County's
<br /> Closure Recommendation.
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