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1!WSLE 1 -'CHECKLIST OF REQUIRED DATA !
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
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<br /> Site Name and Location: Shell Service Station, 2320 N. EI Dorado St., Stockton, San Joaquin County(RB#391146)
<br /> Y 1. Distance to production wells for municipal, domestic, A 2004 sensitive receptor survey identified four water
<br /> agriculture, industry and other uses within 2000 feet of the site. supply wells within 2,000 feet of the Site. The nearest
<br /> well is 1,275'to the west.
<br /> Y 12. Site maps, to scale, of area impacted showing locations of In July 1990, two 8,000-gallon gasoline and one
<br /> any former and existing tank systems, excavation contours and 10,000-gallon gasoline USTs were 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 80', the
<br /> diagrams; _ total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the 150 yof excavated soil is not
<br /> discussed in the available reports.
<br /> Y 5. Monitorin wells remainin on-site, fate; Eight monitoring wells(MW-1 through MW-8) will be properly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from,29'to 40'bgs. Groundwater flow
<br /> elevations and depths to wafer, direction varied from northeast to southeast, and groundwater gradient
<br /> varied from 0.006 to 0.05 ft/ft.
<br /> 7. Tabulated results of all sampling All data adequately tabulanzed in various reports, including closure report.
<br /> _.dr,u ana1y'se-6'
<br />` Detection limits for confirmation
<br /> I. sampling
<br /> QN Lead analyses
<br /> 8. 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 /> Lateral and El Vertical extent of soil contamination
<br /> Lateral and MY Vertical extent o/2roundwater contamination
<br /> 9. Zone o/influence calculated and assumptions used for subsurface remediation The regulatory agency did not require
<br /> system and the zone of capture attained for the soil and groundwater remediation active remediation. .
<br /> system"
<br /> 10.Reports/information FYI Unauthorized Release Form QY QMRs 31 from 3/03 to 7/10
<br /> Ir FY Well and boring logs �Y PAR �Y FRP FY Other Closure Reports(4/10, 8/10)
<br /> Y J 11.Best Available Technology(BAT)used or an explanation for not USTs removal, over-excavation, and natural
<br /> using BAT,' I attenuation.
<br /> UY 12. Reasons why background wasrs Minimal residual soil and groundwater contamination remains on-site.
<br /> ttainable using BAT; _
<br /> Y 13.Mass balance calculation of substance treated The consultant estimated TPH as 1.2 lbs remaining in soil, and 1.4 lbs
<br /> versus that remaining, remaining in groundwater.
<br /> Y. 14. Assumptions,_parameters, calculations and The consultant did not conduct a soil gas survey;however, only
<br /> model used in risk assessments, and fate and benzene and xylenes at 5'bgs, 50'from the f uildmgr exceeded
<br /> transport modeling, Region 2 commercial ESLs for gross contamination in soil. Water
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<br /> quality goals will be reached in 13 years.
<br /> Y 15. Rationale why conditions remaining at site� Soil contamination reportedly is limited in extent. Land use
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<br /> will not adversely impact water quality, health, or (commercial)is not expected to change in the foreseeable future. Vapor
<br /> other beneficial uses;and intrusion risk has been addressed. Water quality goals will be reached
<br /> in 13 ears.
<br /> By: JL:B�j� Comments:In July 1990, two 8,000-gallon gasoline and one 10,000-gallon gasoline USTs were removed from
<br /> the subject Site. Based upon 31 quarters of groundwater monitoring showing a stable plume with a declining
<br /> Date: concentration trend, the limited extent of contamination remaining in soil and groundwater, no foreseeable
<br /> 3/2/2011 changes in land use, and limited threats from groundwater, soil,and soil vapor intrusion, Regional Board
<br /> 7 San Joaauin County's Closure Recommendation
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