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�r Working to Restore Nature using Environmental Protection Agency (EPA) Methods 5030/8015/8020 and total extractable hydrocarbons (equivalent to total petroleum hydrocarbons as diesel [TPHd]) using EPA Method 3510/8015 Samples were analyzed at Sequoia Analytical in Sacramento, California (California Department of Health Services Hazardous Waste Testing Laboratory Certification No. 1624). Copies of the Chain of Custody Records and laboratory analysis reports are attached Results of analyses indicated TPHg was detected in soil samples from borings B-15, B-16, and B-17 at concentrations ranging from 5.4 parts per million (ppm) to 5,100 ppm, the highest concentrations were detected in soil from boring B-16 at a depth of 16 5 feet and 26.5 feet. TPHd was detected in borings B-15, B-16, and B-17, concentrations ranged from 2.0 ppm to 390 ppm (boring B-16) Concentrations of hydrocarbons as gasoline and diesel were below laboratory detection limits in soil samples collected from boring B-14 Results of analyses are shown in Table 1 GROUNDWATER MONITORING On October 25, 1993, RESNA measured the water levels in wells MW-1 through MW-5 and RW-1 and collected groundwater samples from the wells for subjective and laboratory analyses The field methods used are presented as an attachment to this report Floating . product or product sheen was not noted on samples from the wells (Table 2) The depth to water measurements and the elevations of the well casings (Table 2) were used to evaluate the groundwater flow direction and gradient beneath the site (refer to attached Field Procedures) On October 25, 1993, the groundwater gradient beneath the site was 0 007 with a flow direction toward the northeast (Plate 13) Since the previous monitoring event, the groundwater surface has dropped approximately 0 81 foot The direction of groundwater flow has ranged from southeast to northeast since groundwater monitoring was initiated in December 1988 Groundwater samples were analyzed for TPHg using EPA Method 5030/8015 and TPHd using EPA Method 3510/8015 (modified for gasoline and diesel) and for BTEX using EPA Method 5030/602 These samples were analyzed at Sequoia Analytical Copies of the Chain of Custody Records and laboratory analysis reports are attached Results of laboratory analyses indicated dissolved TPHg was detected in samples from wells MW-1, MW-2, MW-4, and RW-1 at concentrations of 1,200 parts per billion (ppb), 52 ppb, 130 ppb, and 61 ppb, respectively Benzene was also detected in well MW-1 at 230 ppb TPHd was detected in wells MW-1 and MW-3 at 100 ppb and 360 ppb, respectively Dissolved TPHd and TPHg concentrations were below laboratory detection limits in monitoring well MW-5 Results of laboratory analyses are summarized in Table 3 • 1112jew/M0094 3