SITE INFORMATION AND CORRESPONDENCE_FILE 2

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1,4BLE 1 -CHECKLIST OF REQUIRED DATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Harry's Auto,2662 North Wilson Way,Stockton,San Joaquin County RB#390406 Y 1. Distance to production wells for municipal, domestic, Ten wells were identified within 2,000 feet of the Site. Two wells agriculture, industry and other uses within 2000 feet of the site; closest towp the Site are approx.450'to the southwest and 900'to the northwest from the Site. YIn 4/89,one 300-gallon,one 2,000-gallon,and two 550- 2. Site maps, to scale, of area impacted showing locations of former gallon USTs were removed.Analytical results from soil and existing tank systems, excavation contours and sample locations, samples collected during the tank excavation confirmed borings and monitoring wells elevation contours, gradients, and nearby that a release had occurred from two of the tanks and the surface waters, buildings, streets, and subsurface utilities; fuel dispenser.Site maps and figures showing tank Y locations,area of excavation,buildings and residual impacts were provided in investigation reports. 3. Figures depicting lithology(cross Cross sections are provided in investigation reports.Site litho/ogy consists of inter- section), treatment system diagrams; bedded layers of silty clay and sand to the total depth investigated 1 10'bgs. y 4. Stockpiled soil remaining on-site or Approx. 150 cubic yards of impacted soil was removed during the tank excavation. No off-site disposal(quantity); documentation for where the soil was taken exists. 5. Monitoring wells remaining on-site, fate; All monitoring wells will be properly destroyed once closure is determined. Y 6. Tabulated results of all groundwater Depth to groundwater varied from 41'bgs to 64'bgs.Groundwater flow direction to the elevations and depths to water, northwest. Y 7.Tabulated results of all sampling and analyses: All data adequately tabu/arized in various reports. MDetection limits for confirmation sampling 0 Lead analyses Y 8. Concentration contours of contaminants found and those remaining in soil The residual pollution is approx. 100'in horizontal groundwater, and both on-site and off-site: length and extends to approx.65'bgs. Y Lateral and Y Vertical extent of soil contamination Y Lateral and Y Vertical extent of groundwater contamination Y 9.Zone of influence calculated and assumptions used for subsurface zone of influence was calculated to be 24'radially remediation system and the zone of capture attained for the soil and from the vapor extraction wells. groundwater remediation system; Y 10.Reports/information FY Unauthorized Release Form M QMRs 0Y Well and boring logs DY PAR EY FRP EY Other Y 11.Best Available Technology(BAT)used or an Soil Vapor Extraction and Air Sparge technologies were implemented as BAT. ex lanation for not using BAT,' y 12.Reasons why background wads unattainable A significant decreasing trend was demonstrated during SVE and AS remediation. However,no post-remedial monitoring has been conducted. using BAT,' calculation of substance Approx.24,700 pounds of gasoline and gasoline constituents were estimated to 13.Mass balance Y treated versus that remaining; be released into the soil and groundwater.An estimated 42,000 pounds of impacts were removed through SVE and AS. 14.Assumptions, parameters, calculations and model-used The SWRCB has determined that remaining soil vapor and groundwater EYort moden concentrations that meet ETCP standards do not pose a significant risk in risk assessments, and fate and transp g; to human or environmental health through indoor or outdoor vapor exposure,or through direct contact. 15.Rationale why conditions remaining at site will not The plume has greatly decreased in size and concentration and is now Y at levels that meet LTCP standards.No supply wells are at risk of being adversely impact water quality, health, or other beneficial impacted by the residual pollution. uses;and N 16.WET or TCLP results n/a Comments: This Site was formerly an automobile service business,and is currently not in use.It is surrounded by other By: commercial properties and there are no plans in the foreseeable future for the Site use to change from commercial use. SVE and AS remediation ran from 2011 until 2014 and significantly decreased the size and concentration of the petroleum cic pollution. The MTBE and 1,2-DCA plumes from this Site have become comingled with those originating from a U-Haul store located 152'northeast from the Site. Post-remedial monitoring was not conducted,there is no estimate as to when water quality will be restored. Residual pollutants from the Site do not threaten nearby domestic wells or pose a threat to human health through indoor or outdoor air exposure or direct exposure. The case meets the criteria of the State Water Board's Date: Low Threat Closure Policy and therefore should not pose a threat to human health or the environment. 8/6/2014