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. KEI-P88-1013 .QR3 January 29 , 1993 Page 2 Water samples were collected from the existing wells (except MW6) on December 30, 1992 . Prior to sampling, the wells were each purged of between 8 and 11 gallons of water by the use of a surface pump. The 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 and stored in a cooler, on ice, until delivery to a state-certified laboratory. HYDROLOGY The measured depth to ground water at the site on December 30, 1992 , ranged between 56 . 83 and 57 . 45 feet below grade. The water levels in all of the wells have shown net increases ranging from 4 . 63 to 5 . 62 feet since September 30, 1992 . Based on the water level data gathered during the quarter, the ground water flow direction appeared to be to the southeast, as shown on the attached Potentiometric Surface Maps, Figures 1, 2, and 3 . The ground water flow direction reported this quarter has changed slightly from the south-southeasterly flow direction reported on September 30 , 1992 . The average hydraulic gradient at the site on December 30, 1992 , was approximately 0 . 004 . ANALYTICAL RESULTS �0 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 2 . 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. DISCUSSION AND RECOMMENDATIONS Based on the analytical results for the ground water samples collected and evaluated to date, and no evidence of free product or sheen in any of the wells, KEI recommends the continuation of the current ground water monitoring and sampling program, per KEI ' s proposal (KEI-P88-1013 . P2) dated August 23 , 1991 , and as modified in KEI ' s report (KEI-P88-1013 .R2) dated July 15, 1992 _ In order to comply with a request from the San Joaquin County Public Health Services (SJCPHS) Department, KEI previously