SITE INFORMATION AND CORRESPONDENCE

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ABLE 1 -CHECKLIST OF REQUIRED DATA / { FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES f Site Name and Location: Flying J Travel Plaza, 1501 N. Jack Tone Rd., Ripon, San Joaquin County(RB#391185) Y 1. Distance to production wells for municipal, domestic, The report did not discuss supply wells or other potential agriculture, industry and other uses within 2000 feet of the site. sensitive receptors;however, Geo Tracker shows one inactive, treated municipal well located 1,000'to the ' south. Y 2. Site maps, to scale, of area impacted showing locations of During dispenser upgrades in May 2009, diesel soil any former and existing tank systems, excavation contours and contamination was confirmed between 1'to 2'bgs in one sample locations, boring and monitoring well elevation sample at dispenser#13114. A 2010 investigation did not contours, gradients, and nearby surface waters, buildings, detect soil contamination from 5'bgs to 20'bgs, but streets, and subsurface utilities; reported groundwater contamination in one grab groundwater sample ffPHd,45 u /L . Y1 3. Figures depicting lithology(cross section), treatment system Site lithology consists of silt and sand to 25', the total diagrams; depth investigated. The volume of excavated soil was not reported during Y 4. Stockpiled soil remaining on-site or off-site disposal (quantity); p g the dispenser upgrades. N 5. Monitoring wells remaining on-site, fate; No monitoring wells were installed. 6. Tabulated results of all groundwater Depth to groundwater was 24'bgs. Regional groundwater flow direction elevations and depths to water, I was estimated as towards the south. 7. Tabulated results of all sampling All data adequately tabularized in various reports,including closure report. and analyses: Y❑ Detection limits forconfnnation sampling QN Lead analyses 8. Concentration contours of contaminants found and those remaining in soil and The extent of the identified groundwater,and both on-site and off-site: contamination is described in the report. Y Lateral and Y Vertical extent of soil contamination - "4 fRI Lateral and Vertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not system and the zone of capture attained for the soil and groundwater remediation required by the lead agency. system; 10.Reports 1 information �Y Unauthorized Release Form QN QMRs FY Well and boring logs PAR El FRP FNI Other Y excavation and natural attenuation. 11.Best Available Technology(BAT) used or an explanation for not using Soil BAT; Y 12. Reasons why background waslis unattainable Minor residual soil contamination remains on-site. BAT;13. :NJ 13.Mass balance calculation of substance treated Initial mass was not calculated by the consultant. versus that remaining; 7Y 14. Assumptions,parameters, calculations and initial 2009 soil sample results(TPHd, 240 mg/kg)show Region 2 model used in risk assessments, and fate and ESLs were exceeded for direct contact and gross contamination. A transport modeling; 2010 grab groundwater result was TPHd,45 ug/L, which does not exceed WQGs. �, 15. Rationale why conditions remaining at site will Soil contamination reportedly is limited in extent. Land use not adversely impact water quality, health, or other (commercial)is not expected to change in the foreseeable future. beneficial uses;and By: JLB Comments During dispenser upgrades in May 2009,soil contamination was observed and confirmed in one sample at dispenser#13114 at the subject site. A 2010 investigation did not detect soil contamination from Date: 5'bgs to 20'bgs under dispenser#13/14, and minimal groundwater contamination(TPHd,45 ug/L)from one 5/31/2011 grab groundwater'sample. Minor residual soil contamination remains on-site. Based upon the limited extent of contamination reported in so!/and groundwater not exceeding WQGs, no foreseeable changes in land use, and minimal risks from soil, soil vapor, and groundwater, Regional Board staff concur with San Joaquin County's Closure Recommendation. '