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N-A-i OW KEI-P91-0202.R5 October 16, 1991 Page 5 sand and silt materials remain in the water within the well casing. Monitoring and well development data are summarized in Table 1. The wells were sampled on September 9, 1991. Prior to sampling, monitoring data was collected and the wells purged of between 5 and 7.5 gallons. slater samples were then collected using a clean Teflon bailer, which was cleaned using a non-phosphate based detergent, and which was rinsed with distilled water prior to sampling each well. The samples were decanted into clean glass VOA vials, which were sealed with Teflon-lined screw caps, labeled, and stored in a cooler, on ice, until delivery to a certified labora- tory. ANALYTICAL RESULTS Water and selected soil samples were analyzed at Sequoia Analytical Laboratory in Concord, California. All samples were accompanied by properly executed Chain of Custody documentation. soil and water samples were analyzed for TPH as gasoline by EPA method 5030 in conjunction with modified 8015, and BTX&E by EPA method 8020. Analytical results of the soil samples collected from the borings for monitoring wells MW1, MW2, and MW3 indicated non-detectable levels of TPH as gasoline and BTX&E, except for samples MW1(27.5) , MW1(32.5) , and MW1(42.5) , which showed levels of TPH as gasoline ranging from 1.9 ppm to 5.0 ppm, and with benzene 1avels ranging from 0.45 ppm to 1.9 ppm. Also, sample MW1(37.5) shored a benzene level of 0.0094 ppm. Additionally, relatively minor amounts of toluene, xylenes, and ethylbenzene were also detected in these four samples. M i Analytical results of the ground water samples collected from monitoring wells MW1 andMW2 indicate levels of TPH as gasoline at 660 ppb and 240 ppb, respectively, Xith benzene levels at 96 ppb and 13 ppb, respectively. In MVAY, TPH as gasoline was noii- detectable, with benzene at 0.49 ppb. Concentrations of TPH as gasoline and benzene detected in ground water samples collected on September 9, 1991, are shown on the attached Site Plan, Figure la. Results of the soil analyses are summarized in Table 3, and the water analyses in Table 2. Copies of the laboratory analyses and Chain of Custody documentation are attached to this report. HYDROLOGY AND GEOLOGY The water table stabilized in the monitoring wells at depths ranging-_from--74.18- to- 74.94--feet__below_the_surface.___The__ground_-_-_ __ _-_ water flow direction appeared to be toward the south on September 9, 1991, with a hydraulic gradient of approximately 0.0033, (based