SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

TABLE 1 - CHECKLIST OF REQUIRED DATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Country Market, 10476 W. Rd., Tracy, San Joaquin County (RB #391189) Y1 1. Distance to production wells for municipal, domestic, A 2014 sensitive receptor survey reported one agriculture, industry and other uses within 2000 feet of the site. Fater supply well 100' southwest of the Site. The well is not threatened by the release due to the well depth and limited vertical extent of pollution. y 2. Site maps, to scale, of area impacted showing locations of any In 11/12, one 350 gallon and one 500-gallon former and existing tank systems, excavation contours and gasoline USTs were removed after being closed in sample locations, boring and monitoring well elevation place in 1986. Site maps and figures showing tank contours, gradients, and nearby surface waters, buildings, locations, excavations, building and residual streets, and subsurface utilities; pollutants were provided in investigation reports. Y1 3. Figures depicting lithology (cross Site lithology consists of silt, sand, and gravel to 20', the total depth section), treatment system diagrams; investigated. No remediation was conducted. No mass estimates given by consultant for soil removed. N 4. Stockpiled soil remaining on-site The stockpiled soil was placed back into the tank pit which was lined with or off-site disposal (quantity); plastic before backfilling. P5. Monitoring wells remaining on-site, No monitoring wells were installed. No petroleum hydrocarbons were detected in the on-site domestic well tested on 14 February 2014, 6. Tabulated results of all groundwater Groundwater was not encountered during the investigation. The domestic well elevations and depths to water; could not be gauged for water level; however, when constructed in 1974 the water level was 78' bgs and the screened interval was from 162' to 182' bgs. 7. Tabulated results of all sampling All data adequately tabulated in various reports. Confirmation samples at 9' bgs and analyses: TPHg, 530 mg/kg was detected below Tank B. Soil contamination was delineated to non-detect in B-1 at 10' bgs and 20' bgs in the tank pit. FYI Detection limits for confirmation sampling ❑N Lead analyses 8. Concentration contours of contaminants found and those remaining in Petroleum pollution was detected in soil and groundwater, and both on-site and off-site: confirmation soil samples, but was not detected during the soil boring Y❑ Lateral and Y❑ Vertical extent of soil contamination investigation. Lateral and R Vertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface An engineered treatment system was not remediation system and the zone of capture attained for the soil and required by the regulatory agency, groundwater remediation system; YJ 10. Reports / information FY Unauthorized Release Form FN QMRs YI Well and boring logs 10 PAR ❑N FRP ❑N Other YJ 11. Best Available Technology (BAT) used or Leak was stopped by removing tanks. an explanation for not using BAT; Unable Reasons why background was/is not No groundwater impacts were detected in the sample from the on-site UUnable usin BAT; water supply well, collected in February 2014. N 13. Mass balance calculation of substance Mass balance was not estimated by the consultant treated versus that remaining; :Y::] 14. Assumptions, parameters, calculations San Joaquin County determined that the Site meets the LTCP criteria and model used in risk assessments, and fate for commercial use. Consultant states site does not represent a and transport modeling; significant environmental or health risk under current use commercial . I, 15. Rationale why conditions remaining at Land use (commercial) is currently a gravel parking lot and the site will not adversely impact water quality, regulatory agency determined that vapor intrusion and dermal contact health, or other beneficial uses; and were not a significant environmental or health risk under current use. By, JLB Comments: In 2008, two USTs were removed from the subject site. Soil at 9' below one of the tanks was impacted by TPHg, at 530 mg/kg. Based on no concentrations of petroleum hydrocarbons detected in soil Date: borings at 10' bgs, and no impacts detected in the on-site water supply well (screened at 162 feet bgs), this 4/23/2015 case meets the LTCP. Regional Board staff concur with San Joaquin County's Closure Recommendation.