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TABLE 1 -CHECKLIST OF REQUIRED DATA•
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Former Unocal#0187,437 E. Miner Ave., Stockton, San Joaquin County(RB#390698)
<br /> Y 1. Distance to production wells for municipal, domestic, A 2009 sensitive receptor survey reported six water
<br /> agriculture,industry and other uses within 2000 feet of the supply wells(750'southwest, 800'south, 1,000'and
<br /> site. 1,100'south southwest, 1,300'southeast, and 1,800'
<br /> southwest) within 2,000'of the site.None of the wells
<br /> are threatened b the release.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of In 1/92, two 10,000-gallon gasoline and one 280-gallon
<br /> any former and existing tank systems, excavation contours waste oil USTs were removed.A previously closed in
<br /> and sample locations, boring and monitoring well elevation place 300-gallon unknown use UST was removed in
<br /> contours,gradients, and nearby surface waters, buildings, 5/92.
<br /> streets,and subsurface utilities;
<br /> Y 3. Figures depicting litho/ogy(cross Site litho/ogy consists of clay,silt,and sand to 153, the total depth investigated.
<br /> section, treatments stem dia rams;
<br /> Y 4. Stockpiled soil remaining on-site Approximately 375 y of excavated soil was transported to Laidlaw
<br /> or off--site dis osa/(quantity); Environmental Services In Buttonwillow.
<br /> Y 5.Monitoring wells remaining on-site, Ninety four(94)monitoring and remediation wells(U-1 through U-26, U-27A,
<br /> ate; U-27B, UV-1, UV-2,ASB-1, NP-1-22, NP-2-22,NP-2-60, NP-2- 116,SP-1A through
<br /> SP-6A, SP-1B through SP-6B, SP-1C through SP-3C,SP-5C, SP-6C, SVP-1A
<br /> through SVP-8A, SVP-1B through SVP-8B, IW-1A through/W--SA,and/W-1A
<br /> throu h IW-56 will be properly destro ed prior to closure.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 20'bgs to 87'bgs. Groundwater flow
<br /> elevations and depths to water; direction varied from north to east. Groundwater gradient varied from
<br /> 0.001 ft/ft to 0.01 Wft.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports.
<br /> and analyses:
<br /> El Detection limits for
<br /> confirmation sampling
<br /> QY Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in The extent of the identified contamination
<br /> soil and groundwater,and both on-site and off-site: is described in the available reports.
<br /> ElLateral and El Vertical extent of soil contamination
<br /> Lateral and El Vertical extent of roundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface The engineered remediation was over-
<br /> remediation system and the zone of capture attained for the soil and excavation,Free Product(FP)removal
<br /> groundwater remediation s stem; from U-1,and ozone injection Ol.
<br /> 10.Reports/information LY Unauthorized Release Form QMRs(54)8-94 toll-12
<br /> FE Well and boring logs El PAR MY FRP Other Site Closure Request, 3/13
<br /> Y 11.Best Available Technology(BAT)used or an UST removal, FP removal, Ol, and natural attenuation.
<br /> explanation for not using BAT;
<br /> ZY 12. Reasons why background was/is Residual soil and groundwater contamination remains.
<br /> ttainable usin BAT;
<br /> Y 13.Mass balance calculation of substance Consultant did not calculate mass estimates.
<br /> treated versus that remafnin ;
<br /> Y 14. Assumptions,parameters, calculations Site is a vacant lot that passed LTCP. Consultant states site does not
<br /> and model used in risk assessments,and fate represent a significant risk.
<br /> and transport modeling;
<br /> y 15. Rationale why conditions remaining at Soil and groundwater contamination reportedly are limited in extent.
<br /> site will not adversely impact water quality, Land use(commercial)is not expected to change in the foreseeable
<br /> health, or other beneficial uses;and future. Consultant estimated time to reach WQGs as 2162. Groundwater
<br /> Plume is stable and declining.
<br /> By: JLB Comments:In 1/92, two 10,000-gallon gasoline and one 280-gallon waste oil USTs were removed,and a
<br /> previously closed in place 300-gallon unknown use UST was removed in 5/92 at the subject site. Residual
<br /> Date: soil and groundwater contamination remains.Based upon the limited extent of contamination reported in
<br /> 5/29/2013 soil and groundwater,a stable and declining concentration plume, no foreseeable changes in future land use
<br /> (commercial), and minimal risks from groundwater,soil vapor and soil, Regional Board staff concur with San
<br /> Joa uin Count 's Closure Recommendation.
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