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r M1004bLE 1 -CHECKLIST OF REQUIRED DATA " FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Location: JLN Farms/Joe Panetta Property, 95 W. Eleventh St., Tracy, San Joaquin County (Case 391152) o production wells for municipal, domestic, A 1997 wen survey for the adjacent Chevron site identified 10 ustry and other uses within 2000 feet of the site. supply wells within 2,000' of the site, with the nearest well 4,300 feet to the south. Bases upon sampling data, no wells are threatened due to this case. ps, to scale, of area impacted showing locations Contained in several reports on file. rmer and existing tank systems, excavation contoursand sample locations, boring and monitoring well elevation contours, gradients, and nearby surface waters, buildings, streets, and subsurface utilities; Yj 3, Figures depicting lithology (cross section), treatment Site lithology consists of sand, silt, and clay to total depth of system diagrams; 35 feet. Y 4. Stockpiled soil remaining on-site or off=silo disposal (quantity); Approximately 730 yds. of contaminated soil excavated during corrective action was transported to Forward Landfin, Manteca_ Y 5. Monitoring wells remaining on-site, fate; A reported 13 monitoring wells installed over time. All monitoring wells will be properly abandoned prior to formal closure per County. 6. Tabulated results of all groundwater Depth to groundwater varied from -8 feet to ^-13 feet below ground elevations and depths to water,' surface (bgs). The groundwater gradient varied from 0.002 to 0.036 ft/ft. The downgradient groundwater flow direction v=aried from northwest to southeast. 7. Tabulated results of all sampling All data adequately tabularized in various reports, including closure report, and analyses: ❑Y Detection limits for confirmation sampling Lead analyses e. 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 shown in applicable YY Lateral and FY] Vertical extent of soil contamination reports. Lateral and N1 Vertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used forsubsurface remediation Over -excavation was the system and the ,zone of capture attained for the soil and groundwater remediation engineered remediation. system; 10. Reports /information QY Unauthorized Release Fomf 0 QMRs (from 2000 to 2009) Yy Well and boring togs Yy PAR nY FRPYy Other; Closure Summary Report, 2009 Y 11. Best Available Technology (BAT) used or an explanation for not using BAT7 Removal of USTs, over -excavation and natural attenuation. Y 12. Reasons why background waslis unattainable using BAT Limited soil and groundwater contamination remain on- site. Y 13. Mass balance calculation of substance treated versus that The consultant estimates TPH-g removed from soil as remaining; 504 pounds, and TPHg remaining in soil as 104 pounds. Y 14. Assumptions, parameters, calculations and model used in Due to the depth of remaining TPHg in soil (12'-15" bgs) risk assessments, and fate and transport modeling; and existence of a vapor barrier installed for the building, a vapor intrusion survey was not required by the regulatory agency, Y 15. Rationale why conditions remaining at site will not adversely Groundwater concentrations continue to decline with impact water quality, health, or other beneficial uses; and many wells already at non -detect. Consultant estimates WQGs reached by 2011. Site no longer poses a threat. By: JLB . Comments: Site (former Phillips station) is located adjacent to a 1997 closed UST site (Chevron), and property "k use (commercial) is not expected to change. Due to remedial efforts in the source'area, confirmation sampling has shown that this site no longerposes a threat to human health and safety or to water quality, Regional Date: 10127109 Board staff concurs with San Joaquin County's recommendation for issuance of a'No Further Action letter.