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. '11013LE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Palisades Gas&Wash#8351Former USA Petroleum(Case 2),2705 Country Club Blvd.,Stockton,
<br /> San Joaquin County(RB#390068)
<br /> Y 1. Distance to production wells for municipal,domestic, A 2001 sensitive receptor survey reported one inactive
<br /> agriculture,industry and other uses within 2000 feet of the site. CalTians well(150'),five domestic wells(600; 7001,
<br /> 80019 900'and 1050')to the south,and two domestic
<br /> wells 750'to the northwest of the site.
<br /> 2. Site maps,to scale, of area impacted showing locations of any A UST system vapor release(6-05)Is suspected as the
<br /> former and existing tank systems, excavation contours and source of the second release of MTBE(Case 2).A
<br /> sample locations, boring and monitoring well elevation contours, source was not found in the soil.
<br /> gradients, and nearby surface waters, buildings, streets, and
<br /> subsurface utilities•
<br /> Y 3.Figures depicting lithology(cross section), treatment system Site lit►ology consists of clay,slit and sand to 93,the
<br /> diagrams; total depth Investigated.
<br /> 4.Stockpiled soil remaining on-site or off-site disposal(quantity); No soil was excavated for Case 2.
<br /> y 5. Monitoring wells remaining on-site, fate, Twenty one monitoring wells(MW-1 through MW-21)and two remediation
<br /> wells W-1 and YEW-3)will be property abandoned.
<br /> d Tabulated results of aff groundwater Depth to groundwater varied from 9'bgs to 17'bgs.Groundwater flow
<br /> elevations and dooms to water, fir`--- -- - --
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports,Including closure report
<br /> and analyses:
<br /> 0 Detection limits for confirmation
<br /> sampling
<br /> 10 Lead analyses
<br /> AJ 8. Concentration contours of contaminants found and those remaining in soil and The extent of the Identified groundwater
<br /> groundwater,and both on-site and off-site: contamination is described in the report
<br /> ©Lateral and ©Vertical extent of soil contamination
<br /> rYll-ateral and rYJ Vertical extent of groundwater contamination
<br /> HI 8. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not
<br /> system and the zone of capture attained for the soil and groundwater remediation required by the lead agency.
<br /> system;
<br /> 10.Reports I information Y Unauthorized Release Form Y QMRs 8191 to 6/10(Cases 1 and 2)
<br /> Qy Well and boring logs My PAR FRP My Other Case 2 Closure Report(10-10)
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not using Soil excavation(Case 1)and natural
<br /> BAT; I attenuation.
<br /> 12. Reasons why background wasris unattainable Minor residual groundwater contamination remains onsite and offsite,
<br /> a47-,- wrth declining concentrations.
<br /> Th9 has e C*1*1 .of T M n aoN was cru eted+ In tbs. TP I
<br /> versus that remainin remaining In groundwater was calculated as 1.1 lb.
<br /> 14. Assumptions,parameters, calculations and The 3.94 confirmationsoil sample results show Region 2 ESLs were
<br /> model used in risk assessments, and fate and exceeded for direct contact(TPHg,benzene,ethylbenzene)and gross
<br /> transport modeling; contamination(TPHg)at 11'bgs, which Is below worker depths.
<br /> Additional soil was reported excavated to 15'bgs In 1995 for the new
<br /> USTs.A J&E model for vapor intrusion from groundwater showed
<br /> acceptable risk levels for benzene and MTBE.
<br /> yJ 15. Rationale why conditions remaining at site will Soil and groundwater contamination reportedly is limited In extent
<br /> not adversely impact water quality, health, or other Land use(commercial)is not expected to change In the foreseeable
<br /> beneficial uses•and I future. Water quality goals QGs)will be reached in 2013.
<br /> By: JLB Comments One 6,000-gallon,one 8,000-gallon and one 40,000-gallon gasoline USTs,and one 1,000-gallon
<br /> waste oil UST were removed 3-94(Case 1).A 2005 UST system vapor release is suspected as the source of
<br /> Date: the second release of MTBE(Case 2)to groundwater at the subject site,since no soil source was
<br /> 8/11/2011 discovered. Minor Case 2 residual groundwater contamination remains and groundwater concentrations are
<br /> declining,and projected to reach WQGs in 2013. Based upon the limited extent of contamination reported in
<br /> soil and groundwater,no foreseeable changes in land use,and minimal risks from soil,soil vapor,and
<br /> roue ter Realonal Board staff concur with Son Joa uin County's Closure Recommendation.
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