SITE INFORMATION AND CORRESPONDENCE FILE 2

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TABLE 1 -CHECKLIST OF REQUIREd'cIATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: 7-Eleven Store#14117,2725 Country Club Boulevard,Stockton,San Joaquin County Y 1. Distance to production wells for municipal, domestic, welve domestic water wells were identified within 2,000 ft.of the agriculture, industry and other uses within 2000 feet of the siteite. The closest well is located approx.400 ft.northwest and up- T'- gradient.None of the wells are at risk from impacts from the Site. Y 2. Site maps, to scale, of area impacted showing locations of former In July 1998, three 10,000-gallon USTs were removed and existing tank systems, excavation contours and sample locations, from the subject Site. Two new 10,000-gallon gasoline USTs were installed in the same location.Site maps and borings and monitoring wells elevation contours, gradients, and nearby figures showing tank locations,area of excavations, surface waters, buildings, streets, and subsurface utilities; buildings and residual pollutants were provided in investigation reports. The replacement tanks and all associated piping and dispensers were removed in 2013. Y 3. Figures depicting lithology(cross Cross sections figures are available in various reports.Site lithology consists of clay Section), treatment System diagrams; and silt from grade to approximately 15 ft.bgs.From 15 ft.bgs to total depth of 110 feet bgs of investigation,the lithology consists primarily of alternating layers of fine-grained sand,silt and clayey silt. Y 4. Stockpiled soil remaining on-site or Soil from excavation and site activities was transported to TPS Technologies sites in off-site disposal(quantity); Ade/anto and Richmond, CA. Y 5. Monitoring wells remaining on-site, fate; All monitoring wells will be properly destroyed once Site closure is determined Y 6. Tabulated results of all groundwater Depth to groundwater has varied from 5'bgs to 11'bgs.Groundwater flow direction is elevations and depths to water, to the southeast. Y 7. Tabulated results of all sampling and analyses: All data is adequately tabu/arized in various reports. ❑Y Detection limits for confirmation sampling FY]Lead analyses Y 8. Concentration contours of contaminants found and those remaining in soil The remaining impacted groundwater pollution and groundwater, and both n-site and off-site: extends to 45 ft.bgs. The horizontal extent is FY]Lateral and LYJ Vertical extent of soil contamination approximately 75 ft. EY Lateral and Fy-1Vertical.extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface oxygen injection wells were designed to reduce 7-1remediation system and the zone of capture attained for the soil and evaluated concentrations of petroleum hydrocarbonsgroundwater remediation system; hydrocarbons detected in the area directly around the former tank pit and had approx.25 ft.of radial influence. Y 10.Reports/information MY Unauthorized Release Form FY QMRs YM Well and boring logs HN PAR ❑Y FRP MY Other Y 11.Best Available Technology(BAT)used or an UST replacement soil excavation,and oxygen injection were implanted as BAT. explanation for not using BAT Y 12.Reasons why background warms unattainable The impacted groundwater plume appeared to be decreasing naturally in size and using - concentration during rebound monitoring performed from 2009 intermittently until g LAT' 2013. Y 13.Mass balance Calculation of substance Approx.75 gallons of petroleum hydrocarbons were present in the soil prior to remediation. treated versus that remaining; 14.Assumptions,parameters, calculations and model used The remaining soil vapor and groundwater concentrations meet LTCP Y in risk assessments, and fate and transport modeling; standards and can therefore be assumed to not pose a significant risk to human or environmental health through indoor or outdoor vapor exposure,or through direct contact. 15.Rationale why conditions remaining at site will not Site is expected to meet background conditions in 20 years.Soil and Y 15.Ratio impact l water quality, a other beneficial groundwater impacts are reportedly limited in extent and show a stable Yq Y and decreasing trend and does not pose a threat to human health or uses;and the environment according to Stantec Consulting Services,Inc. N 16.WET or TCLP results n/a Comments: The Site is currently in use as a convenience store and there are no plans in the foreseeable future for the By:CLC land use to change from commercial to residential.In July 1998,three 10,000-gallon USTs were removed from the subject Site and replaced. The replacement tanks and all associated piping and dispensers were removed in 2013. Oxygen injection into the ground water was performed from 2009 intermittently until 2013. Current Site conditions meet the criteria of the Date: State Water Board's Low Threat Closure Policy for commercial land use and therefore should not pose a threat to human 7/29/2014 health or the environment.