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KEI-P88-1013 .QR4 April 19 , 1993 Page 2 quarter. The monitoring data collected this quarter are summarized in Table 1. Water samples were collected from all of the existing wells (except MW6) on March 25, 1993 . Prior to sampling, the wells were each purged of between 10 . 5 and 13 . 5 gallons of water by the use of a surface pump. During purging operations, the field parameters pH, temperature, and electrical conductivity were recorded (except for well MW13) and are presented in Table 2 . Once the field parameters were observed to stabilize and a minimum of four casing volumes had been removed from each well, samples were then 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 and stored in a cooler, on ice, until delivery to a state-certified labora- tory. HYDROLOGY The measured depth to ground water at the site on March 25 , 1993 , ranged between 53 . 28 and 54 . 07 feet below grade. The water levels in all of the wells have shown net increases ranging from 3 . 34 to 3 . 55 feet since December 30, 1992 . Based on the water level data gathered during the quarter, the ground water flow direction appeared to vary from the east-northeast to the east-southeast, as shown on the attached Potentiometric Surface Maps, Figures 1, 2 , and 3 . The ground water flow direction has varied from south- southeast to east-northeast since July of 1992 . The average hydraulic gradient across the site on March 25, 1993 , was approximately 0 . 003 . ANALYTICAL RESULTS The ground water samples 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/modi- fied 8015, benzene, toluene, xylenes, and ethylbenzene by EPA method 8020, and for EPA method 8010 constituents. The ground water sample analytical results are summarized in Table 3 . The concentrations of TPH as gasoline and benzene detected in the ground water samples collected this quarter are shown on the attached Figure 4 . Copies of the laboratory analytical results and the Chain of Custody documentation are attached to this report.