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0 RECEIVED • Section 3.0 FEB 2 6 2014 Conclusions and Recommendations ENVIRONMENTAL 1 IBM 1 BEPARTMENT In 2012, the contents of the UST were removed,the tanks and piping were triple rinsed, and appropriate measures were completed for in-place temporary closure of the two 12,000-gallon USTs and one 15,000-gallon UST and associated equipment. In January 2014, Waterstone was present to witness Tafoya and Associates of Chino, California for the scope of work of UST and fuel line removal, which included Waterstione conducting soil sampling beneath USTs, fuel lines, and from the soil stockpiles. On January 9, 2014, Tafoya and Associates of Chino, California performed the UST removal activities on behalf of Thrifty which consisted of concrete removal, overburden soil excavation via backhoe, stockpiling of soil with cover in preparation for UST removal, and removal of the fuel dispensers for future re-use. Volatile organic compound (VOC) emissions were monitored by Waterstone using a calibrated hand held Mini-Rae photo-ionization detector(PID) during soil excavation activities.No elevated VOCs readings were detected above background levels and no noticeable hydrocarbon odors were detected during the entire UST soil excavation process. Soils were stockpiled awaiting soil analytical results from the four soil samples (SP-1 through SP-4) collected from the stockpile on January 9, 2014. On January 9, 2014, the tank were triple rinsed, the contents were removed via vacuum truck, and the headspace was inspected and analyzed Adams Services of Gardena, California,with an organic vapor analyzer and determined to be • clean and safe for transport and recycling. The USTs were then inerted with 30 pounds of dry ice per 1,000 gallon volume as required by the onsite Stockton Fire District Inspector Robert Kubena. On January 9, 2014, the tanks were removed by crane and the associated fuel piping was removed and chopped up with a chop-saw into approximately 2 to 3 foot long pieces. The piping was removed and recycled by SIC Lovelace of Manteca, California. The USTs were loaded onto a flat-bed truck with a crane, marked for transport, and taken to Schnitzer Steel of Oakland, California for recycling. San Joaquin County Environmental Health Department(SJCEHD) Inspector Jeff Wong, along with Stockton Fire District Inspector Robert Kubena, were present onsite during the tank removal process and approved the tanks for offsite transport and disposal. All five soil samples collected from beneath the fuel lines did not contain detectable concentrations of any of the chemicals of concern. Stockpiled soil samples were also non-detect for all analytes of concern with the exception of sample SP-1 which contained total xylenes at a concentration of 0.0015 J milligrams per kilogram (mg/kg). The"J" denotes that the concentration detected was above the laboratory method detection limit but below the laboratory reporting limit. Four of the nine soil samples collected from beneath the USTs had very low detectable concentrations of some of the analytes of concern(T89-S-18', T89-N-18', T89-M-18', and T87- W-18'). Sample T89-S-18' contained benzene (0.0061 mg/kg), toluene (0.040 mg/kg), ethylbenzene (0.0023 J mg/kg), and xylenes (0.018 mg/kg). Sample T89-N-18' contained • benzene (0.0011 J mg/kg),toluene (0.013 mg/kg), ethylbenzene (0.0025 J mg/kg), and xylenes Thrifty Station No.401 5 Waterston Environmental,Inc. February 2014 Project 13-140