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`'(ABLE 1 -CHECKLIST OF REQUIRED DATA— <br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES <br /> Site Name and Location: Parkinson's 1-5 ARCO Service Station, 3250 W. Hammer Ln., Stockton, San Joaquin County <br /> (RB#391091) <br /> y J1. Distance to production wells for municipal,domestic, A 2008 sensitive receptor survey reported no water <br /> agriculture,industry and other uses within 2000 feet of the site. supply wells are located within 2,000 of the Site. <br /> Y 2. Site maps, to scale, of area impacted showing locations of any In 1/00, dispensers and piping were removed and <br /> former and existing tank systems,excavation contours and replaced, and TPH was detected in confirmation soil <br /> sample locations, boring and monitoring well elevation samples. <br /> contours,gradients, and nearby surface waters, buildings, <br /> streets, and subsurface utilities; <br /> Y Site lithology consists of clay,silt,and sand to 90', the total depth investigated. <br /> 3. Figures depicting lithology(cross <br /> section), treatment sstem diagrams; <br /> Y Approximately 262 tons excavated soil was transported to Forward Landfill in <br /> 4. Stockpiled soil remaining on-site <br /> Manteca <br /> or off-site disposal(quantity); <br /> o5. Monitoring wells remaining on-site, Seven(7)monitoring wells(MW-1 through MW-7)and eight nested(8) <br /> ate; remediation wells(IW-lA/B through IW-4A/B)will be properly destroyed prior to <br /> closure. <br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 10'bgs to 18'bgs. Groundwater flow <br /> elevations and depths to water; direction was towards the east-northeast. Groundwater gradient was 0.001 ft/ft. <br /> 7. Tabulated results of all sampling All data adequately tabu/arized in various reports. <br /> and analyses: <br /> Y❑ Detection limits for <br /> confirmation sampling <br /> QY Lead analyses <br /> LY J 8. Concentration contours of contaminants found and those remaining The extent of the identified contamination is <br /> in soil and groundwater,and both on-site and off-site: described in the available reports. <br /> ElLateral and Y❑Vertical extent of soil contamination <br /> ©Lateral and ©Vertical extent of groundwater <br /> contamination <br /> 9. Zone of influence calculated and assumptions used for subsurface Dual phase(soil vapor and groundwater <br /> remediation system and the zone of capture attained for the soil and water)extraction(DPE), and ozone sparging <br /> groundwater remediation system; (OS) with hydrogen peroxide(H2O2) <br /> injections were pilot studied as the <br /> engineered remediation. <br /> 10.Reports/information❑Y Unauthorized Release Form QY QMRs(40)9-00 to 4-12 <br /> FY] Well and boring logs IS] PAR FRP ❑Y Other O3/H2O2 Pilot Study&Closure Report, 1/13 <br /> YJ 11.Best Available Technology(BAT)used of an Dispensers/piping removal,over-excavation, DPE10S/H2O2 <br /> explanation for not using BAT pilot studies,andnaturalattenuation. <br /> Y 12. Reasons why background was/is Residual soil and groundwater contamination remains. <br /> ttainable using BAT, <br /> :YD 13.Mass balance calculation of DPE removed approximately 23 lbs. TPH from soil.Residual mass in soil is <br /> substance treated versus that remaining; 8,204 lbs. of TPH and 0.0075 lbs. of TPH in groundwater. <br /> Y 14. Assumptions,parameters, Site is an active service station(no soil vapor survey). Soil exceeds LTCP <br /> calculations and model used in risk benzene(8.47 mg/kg)at 10'bgs, below typical worker exposure depth. <br /> assessments,and fate and transport Otherwise,passed LTCP. Consultant states site does not represent a <br /> modeling; significant risk. <br /> Y 1 15. Rationale why conditions remaining Soil and groundwater contamination reportedly are limited in extent.Land <br /> at site will not adversely impact water • use(commercial)is not expected to change in the foreseeable future. <br /> quality, health, or other beneficial uses; Consultant estimated WQGs will be reached by 2026. Groundwater plume is <br /> and stable and declining. Has SWRCB UST CUF recommendation for closure. <br /> By: J Comments:In 1/00, dispensers and piping were removed and replaced, and TPH was detected in <br /> confirmation soil samples at the subject site.Residual soil and groundwater contamination remains.Based <br /> Date: upon the limited extent of contamination reported in soil and groundwater, a stable and declining <br /> 5/14/2013 concentration plume, no foreseeable changes in future land use(commercial),and minimal risks from <br /> groundwater,soil vapor and soil, Regional Board staff concur with San Joaquin County's Closure <br />