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S E C 0 R 7-Eleven Store#32262 Site Assessment Report • December 12, 2003 Page 5 disposable Teflon® bailer, placed into appropriate EPA-approved containers, labeled, logged onto chain-of-custody documents, and transported on ice to a California state-certified laboratory The samples were preserved on ice and transported under chain-of-custody manifest to Kiff Analytical LLC, in Davis, California, for analysis of TPHg, BTEX, fuel oxygenates MtBE, ELBE, DIPE, TAME, and TBA, 1,2-DCA, and EDB by EPA Method 8260B Waste Disposal Soil generated during drilling was temporarily stored onsite in properly labeled 55-gallon drums Four discrete soil samples were collected from the drums and transported to Kiff Analytical under chain-of-custody documentation for profiling The four discrete sod samples were combined in the laboratory into one composite sample (C0MP-1A,1B,1C,D) and analyzed for TPHg, BTEX, and MtBE by EPA 8260B (Table 1) Belshire Environmental Services Inc transported the non-hazardous sod and well development water on November 5, 2003 Sixteen drums of soil were recycled at the TPS Technologies Sod Recycling facility located Adelanto, California, and seven drums of water were disposed of at the Demenno Kerdoon facility located in Compton, California RESULTS OF SAMPLING ANALYSIS Sail Sample Analytical Results MtBE was reported in soil samples collected from MW-2, MW-3, MW-5, and MW-6D at concentrations ranging from 0 0079 mg/kg (MW-3, 16 feet bgs) to 9 5 mg/kg (MW-5, 15 feet bgs), " (Figure 2 and Table 1) TAME was reported in sod sample MW-6D (19 5') at a concentration ofx 0 0091 mg/kg TBA was reported in soil samples collected from MW-5 and MW-6D at concentrations ranging from 0 010 mg/kg (MW-6D, 10 feet bgs) to 2 2 mg/kg (MW-5, 10 feet bgs), (Figure 2 and Table 1) However, the lab report states that the TBA results may be biased slightly high because a fraction of MtBE (up to 5%) converts to TBA during the analysis Soil samples collected from MW-1 through MW-5, and MW-6D, did not contain TPHg, BTEX, DIPE, EtBE, 1,2- DCA, or EDB above laboratory reporting limits Copies of the laboratory reports are included in Attachment E Groundwater Monitoring and Groundwater Sample Analytical Results On October 30, 2003, the depth to water was measured in monitoring wells MW-1 through MW-5, and MW-6D, from top of casing (TOC) using a water level indicator to within 0 01 feet bgs Dissolved oxygen readings were also collected from the wells using a YSI Model 550A dissolved oxygen meter equipped with a down-hole sensor The groundwater elevation contour map indicates that groundwater flow direction is toward the north at a gradient of 0 004 feet per foot (ft/ft) (Figure 3) Note that MW-6D was not used in contouring MtBE was reported in groundwater samples collected from MW-2 (1,700 ug/L), MW-3 (95 ug/L), MW-4 (1 9 ug/L), MW-5 (120,000 ug/L), and MW-6D (270 ug/L) (Figure 4 and Table 2) TAME was reported in MW-5 at a concentration of 210 ug/L and in MW-2 at 2 6 ug/L TBA was reported in MW- 5 at a concentration of 15,000 ug/L TPHg, BTEX, DIPE, EtBE, 1,2-DCA, and EDB were not • detected above laboratory reporting limits in groundwater samples from MW-1 through MW-5, and L ,r3 P 32262 Assessment Report SECOR Intemational Incorporated w� � u�