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LE 1 -CHECKLIST OF REQUIRED DATA <br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES <br /> Site Name and Location: Quik Stop Station No.076, 1030 Olive Avenue, Stockton, San Joaquin County(RB#391113) <br /> Y 1. Distance to production wells for municipal,domestic, Five domestic and one water supply well are located <br /> agriculture, industry and other uses within 2000 feet of the site. within 2,000 feet of the Site. The inactive water supply <br /> well is 450'NE and a domestic well is 450'NW of the Site. <br /> �r 2. Site maps, to scale, of area impacted showing locations of In October 1998, two 10,000-gallon gasoline USTs were <br /> any former and existing tank systems, excavation contours and removed. <br /> sample locations, boring and monitoring well elevation <br /> contours, gradients, and nearby surface waters, buildings, <br /> streets, and subsurface utilities; <br /> Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay, silt, and sand to 75; the <br /> 7 <br /> diagrams; total depth investigated: <br /> N 4: Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 607 tons of over-excavated in M v tec soil was <br /> trans'ported to Forward Landfill in Manteca. i <br /> y 5. Monitoring wells remainingon-site, fate; One monitoring well(MW-1)will be properly abandoned. <br /> 6. Tabulated results of all groundwater Depth.to groundwater varied from 55'to 66'bgs. Groundwater flow• <br /> elevations and depths to water; direction and groundwater gradient could not be calculated with one <br /> well. <br /> 7. Tabulated results of all sampGn _ All data adequately tabularfzed in various reports, including closure report. <br /> and analyses: <br /> Y❑ Detection limits for confirmation <br /> sampling <br /> �Y Lead analyses <br /> _yjt3. 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 /> 0 Lateral and Vertical extent of soil contamination <br /> Lateral and Vertical extent,of groundwater contamination <br /> 9. Zone of influence calculated and assumptions used for subsurface remediation Over-excavation was the only approved <br /> system and the zone of capture attained for the soil and groundwater remediation remediation. <br /> s stem; <br /> 10.Reports/information 0 Unauthorized Release Form QMRs '20 from 7/03 to 12/09 <br /> ❑y Well and boring logs 10 PAR 0 FRP 0 Other Soil Vapor Investigation(11-09)and Response <br /> Letter 5110 <br /> Y 11.Best Available Technology(BAT)used or an explanation for not USTs removal, over-excavation, and natural <br /> usin BAT; attenuation. <br /> Y 12. Reasons why background was4s Minimal residual soil and groundwater contamination remains on-site. <br /> ttainable using BAT,• The regulatory agency concurs with the consultant that an offsite <br /> originating plume is responsible for TPHg, 380 ug1L detected in MW-1 <br /> _on_12109. -- - - - <br /> 7Y 13.Mass balance calculation of substance treated The consultant did not estimate mass removed by over-excavation or <br /> versus that remaining; mass remaining in groundwater.All soil boring and grab groundwater <br /> results subsequent to tank pull and over-excavation were reported ND. <br /> Y 14. Assumptions, parameters, calculations and The second of two soil vapor surveys passed the ESLs and CHHSLs. <br /> model used in risk assessments, and fate and The consultant blamed the Summa Canister for the first round of false <br /> transport modeling; Positives. <br /> Y 15. Rationale why conditions remaining at site Soil and groundwater contamination reportedly is limited in extent. <br /> will not adversely impact wafer quality, health, or Land use(commercial)is not expected to change in the foreseeable <br /> other beneficial uses;and future. Vapor intrusion risk has been addressed. Water quality goals <br /> will be reached in 2 years. <br /> By: JLB� Comments:In October 1998, two 10,000-gallon gasoline USTs were removed from the subject Site.Based <br /> upon 20 quarters of groundwater monitoring showing a plume with declining concentrations, the limited <br /> Date: extent ofcontamination remaining in soil and groundwater, no foreseeable changes in land use, and limited <br /> 9/1/2010 threats from groundwater, soll and soil vapor intrusion, Regional Board staff concur with'San Joaquin <br />