SITE INFORMATION AND CORRESPONDENCE_FILE 2

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--FABLE 1 -CHECKLIST OF REQUIRED DATA — FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Fremont Shell Station,2494 East Fremont Street,Stockton,San Joaquin County Y In 2001,a sensitive receptor survey was conducted.Four water 1. Distance to production wells for municipal, domestic, supply wells were identified within a 2,000-foot radius of the site. agriculture, industry and other uses within 2000 feet of the site; The closest well is a domestic well about 600 feet east-southeast Y of the site.A water sample was collected from this well in 2009 that confirmed no im act to this well. Two 5,000 gallon, two 8,000-gallon tanks were removed 2. Site maps, to scale, of area impacted showing locations of former in 1996. Two gasoline and one waste oil tank, and existing tank systems, excavation contours and sample locations, dispensers,and product piping were removed in 2005. y borings and monitoring wells elevation contours, gradients, and nearby Site maps showing the location of former and current surface waters, buildings, streets, and subsurface utilities; tanks, buildings and streets were provided in reports. 3. Figures depicting lithology(cross Coarse-grained sediments occur at varying thicknesses at three depth intervals;10 to Y section), treatments stem diagrams; 30 ft.bgs, 70 to 85 H.bgs and 105 to 115 ff.bgs. Borings and cross-sections provided Y 9 in reports. No treatment was conducted. 4. Stockpiled Soil remaining on-site or 103 tons of soil and pea gravel were disposed at the Allied Waste Industries Forward Y P 9 landfill in Manteca in 2005. San Joaquin Co. will confirm waste from well destruction is of(-Site disposal(quantity); removed before final closure. 5. Monitoring wells remaining on-site, fate; Ten groundwater monitoring wells,six shallow and four deeper-zone well on-site. Wells 9 9 will be properly destroyed under permit from San Joaquin Co. rior to closure. Y 6. Tabulated results of all groundwater Depth to g.w.ranged from 41 to 57 k.bgs, Groundwater gradient in both the shallow and deeper zones predominantly south.-southeast elevations and depths to water, Y 7.Tabulated results of all sampling and analyses: Tabulated results are presented in the Closure Request Report. MDetection limits for confirmation sampling ElLead analyses Y 8. Concentration contours of contaminants found and those remaining in soil and groundwater, and both on-site and off-site: Lateral and❑ Y Vertical extent of soil contamination Contaminant contours presented in closure y Lateral and ❑Vertical extent of groundwater contamination Request Report for soil and groundwater. Y Y N 9. Zone of influence calculated and assumptions used for subsurface No cleanup actions were conducted at this Site. remediation system and the zone of capture attained for the soil and groundwater remediation system; Y 10.Reports/information FY Unauthorized Release Form nY QMRs EY Well and boring logs HN PAR [!]FRP FY Other Y 11.Best Available Technology(BAT) used or an Excavation of 103 tons of soil and pea gravel along with MNA effectively removed explanation for not using BAT,' secondary source from the site y 12.Reasons why background wasfis unattainable Contaminant concentrations are decreasing, the areal extent of the pollution is using BAT,' shrinking and background is predicted to be achieved through natural 9 degradation. y 13.Mass balance calculation of substanceAbout 833 lbs.(135 gallons)of total petroleum hydrocarbons were calculated to treated versus that remaining; -be remaining in soil and 9.5 lbs.(1.5 gallons)remain in groundwater 14.Assumptions,parameters, calculations and model used Mass of pollutants calculated on an estimated average in risk assessments, and fate and transport modeling; Y concentration of pollutants concentration to a specific volume of impacted soil 15.Rationale why conditions remaining at site will not Contaminant concentrations are decreasing,the areal extent of the pollution is shrinking and background is predicted to be achieved Y adversely impact water quality, health, or other beneficial through natural degradation. uses;and N 16.WET or TCLP results NA By: Comments: The site is an operating Shell-branded service station in a mixed commercial and residential area. An up-gradient Arco service station is an open UST case.Two 5,000-gallon,two 8,000-gallon tanks were removed in cic 1996. Two gasoline and one waste oil tank, dispensers,and product piping were removed in 2005. Benzene and 1,2- DCA were the predominant contaminants of concern at this Site. Horizontal and vertical delineation indicated the hydrocarbon impacts were confined to the Shell property. Vertical impacts extended to about 150 feet below ground Date: surface. Concentrations are naturally decreasing and the areal extent of impacts are shrinking. No prediction when 9/25201a water quality will be restored was provided.