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this report. • Findings 1 The groundwater elevation at time of monitoring was lower than the last monitoring event by as much as 1.6 feet. MW-1 continues to have the highest concentration of gasoline contamination for TPHg at 169,000 ppb. which is higher than 132,000 ppb. in the last sampling event. Monitoring wells MW-7S, MW-8S, and MW-8D were analyzed at non-detect for all analytes. MW-9, the deepest of ail the monitoring wells, continues to show improvement with TPHg= 117 ppb. The groundwater hydraulic gradient was calculated at S=0.008 with the down slope in the west direction, which is a deviation from the historical data. Typically the hydraulic gradient is down slope to the northeast. The gradient is determined by the first ground water elevation data of MW-1, MW-2, and MW-3 (see a site map attached). Conclusions The hydraulic gradient for this monitoring event is not in the more traditional hydraulic gradient direction of northeast. The slope of the hydraulic gradient is steeper for this event than for the last event. In general,all of the monitoring well groundwater samples,with the exception of MW-1 and MW-S, yielded lower concentrations of TPHg than last quarter.The MW-1 groundwater sample results were in a lower range of concentration than last years third quarter monitoring event. Recommendations AD The author recommends that monitoring well sampling be continued on a quarterly basis. The EDH has requested that this site be analyzed for both 1,2 DCA and EDB. It is recommended that this analysis be completed in the fourth quarter of this year Work in Progress The extraction well is installed. The work plan calls for mobilization of the 21,000 gallon tank and pump installation for the pump test. This work will be started when the UST Fund is current on reimbursement for this site. At the present time, funds for the completion of this work plan are not available. Spoil removal and site maintenance is planned for the near future. Please contact Ervin Rifenburg of this office at (209)368-9381 if you have any questions on this report. Respectfully submitted, Q�uFEss�o Foothill En ee Ervin Rifen g ? J" • Gi411 cc: Michael D. & Sharon Olivarez, 436 W. Scotts Ave. Stockton, Ca. 3