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TAB* 1 - CHECKLIST OF REQUIREATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES New West Petroleum#1003/Flag City Shell, 6437 Banner St., Lodi,San Joaquin County (#391163) Site Name and Location: 1. Distance to production wells for municipal, domestic, agriculture, The nearest supply well is 700' Y south-southeast of the USTs.Additional industry and other uses within 2000 feet of the site. supply wells are approximately 1600'southeast,and 1100'and 1500'north of the Site. Y Site maps, to scale, of u area impacted showing locations osf any former and existing tank MTBE vapor release from the ample locations, boring and monitoring well elevation USTs system was spected systems, excavation contours and s contours, radiants, and nearbysurface waters, buildings streets, and subsurfs a thtology consists of clay,,silt, and sand Y 3. Figures depicting lithology(cross section), treatment system diagrams; to 120 feet, the total depth investigated. Besides properly disposed investigative derived waste, Y 4. Stockpiled soil remaining on-site or off-site disposal(quantfy). no soil was removed. All monitoring and remediation wells were proper/y abandoned by Y 5. Monitoring wells remaining on-site, fate; 23 October 2012. Depth to groundwater varied from 10 to 22 feet below ground surface. 6. Tabulated results of all groundwater The groundwater gradient varied from 0.001 to 0.003 ft/ft, and the elevations and depths to water, downgradient direction was redominant/ to the east-southeast. 7. Tabulated results of all sampling and All data adequately tabularized in various reports. analyses: 0 Detection limits for confirmation sampling 10 Lead analyses ent of contamination is 8. Concentration contours of contaminants found and those remaining in soil and adequately defined by soil borings groundwater, and both on-site and off-site: and monitoring wells. 0 Lateral and Vertical extent of soil contamination © Lateral and © Vertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface remediation system7treatment. proved acgroundwater i e re andiation was and the zone of capture attained for the soil and groundwater remediation system; pump 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRs ;FurtherAction 05 to 6/11 ❑Y Well and boring logs ❑Y PAR ❑Y FRP ❑Y Other, Report 10/11BAT used oran ex lavat on for not usingBroundwaterpump and treatment, andY 11.Best Available Technology( ) p atural attenuation. Minor residual soil and groundwater contamination Y 12.Reasons why background was4s unattainable using BAT,' remain. Consultant estimates 260.5 lbs. of MTBE as initial mass Y 13.Mass balance calculation of substance treated versus that in groundwater. Approximately 0.62 tbs. of dissolved remaining; MTBE remains in groundwater and 22.15 tbs. remains adsorbed in saturated soil. Site passed Low I hreat Closure olicy.A risk Y 14. Assumptions, parameters, calculations and model used in assessment passed the ESLs for soil and the potential risk assessments, and fate and transport modeling; for vapor intrusion.Fate and transport modeling showed no risk to sensitive rece tors. ritsoil c Y 15. Rationale why conditions remaining at site wited in ll not adversely Groundwater t. Sensitive er eceptorsaare not threatemination are ned erd. WQGs will impact water quality, health, or other beneficial uses;and be met bE 2021. ff Comments:A MTBE vapor release from the USTs system was suspected as the cause of the release at the subject Site. Based upon evidence of a stable plume with declining concentrations, no threat to supply wells, limited risk of vapor intrusion or direct contact exposure, no change to Site use(commercial), and limited extentof contamination present in soil and groundwater, Regional Board staff recommends closure for the Site.