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i KEI-P91-0202 .QR5 October 27 , 1993 Page 2 Water samples were collected from all of the wells on September 28, 1993 . Prior to sampling, the wells were each purged of between 3 and 7 gallons of water by the use of a surface pump. Due to technical difficulties, the field parameters pH, temperature, and electrical conductivity were not measured. However, a minimum of four casing volumes were purged from each well prior to sampling. Samples were collected by the use of a clean Teflon bailer. The samples were decanted into clean VOA vials that were then sealed with Teflon-lined screw caps, labeled and stored in a cooler, on ice, until delivery to a state-certified laboratory. HYDROLOGY The measured depth to ground water in the wells at the site on September 28 , 1993 , ranged between 74. 18 and 75 . 44 feet, except for well MW5, in which the depth to ground water was measured at 61 . 32 feet. Similar to previous quarters, the ground water elevation in well MW5 on both monitoring events was significantly higher (approximately 10 feet) than the ground water elevation in all the other wells. This occurrence is considered to be a localized perched condition, and thus the data from well MW5 was not used in calculating ground water contours. The water levels in all of the wells have shown net decreases ranging from 2 . 53 to 2 . 72 feet since March 26, 1993 , except for well MW5, in which a net increase of 0. 39 feet was observed. Based on the water level data gathered during the semi-annual period, the ground water flow direction appeared to be predominantly to the south (varying from the south- southwest to the south-southeast) , as shown on the attached Potentiometric Surface Maps, Figures 1 and 2 . The flow direction has been predominantly to the south (varying from the southwest to the southeast) since December of 1991 (five consecutive reporting periods) . The average hydraulic gradient at the site on September 28 , 1993 , was approximately 0 . 003 . ANALYTICAL RESULTS The ground water samples collected this quarter were analyzed at Sequoia Analytical Laboratory and were accompanied by properly executed Chain of Custody documentation. The samples were analyzed for total petroleum hydrocarbons (TPH) as gasoline by EPA method 5030/modified 8015, and benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA method 8020. The analytical results of all of the ground water samples collected from the monitoring wells to date are summarized in Table 2 . The concentrations of TPH as gasoline and benzene detected in the ground water samples collected this semi-annual period are shown on the attached Figure 3 . Copies of the laboratory analytical results and the Chain of Custody documentation are attached to this report. I