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C C A M B R A GWE system extracted groundwater from well EW-1 at approximately five gallons per minute. An estimate of contaminant mass removed by the GWE system is summarized in the following table. MASS REMOVAL BY GROUNDWATER EXTRACTION Constituent Total Removed Total Hydrocarbons 1.8 lbs MTBE 15.2 lbs Water 2,295,500 gals Duringthe June 19 2001 meeting with San Joaquin Count Public Health Services SJCPHS � g q Y ( ), Equiva, and Cambria, it was agreed that Cambria would shut down the GWE system for the third and fourth quarters of 2001 and monitor gasoline constituent concentrations to determine if there is any rebound in concentrations. Cambria evaluated the groundwater sampling data collected from monitoring wells at this site since the GWE system was shut down. The groundwater analytical data suggest that there has been no rebound in gasoline coTiStituent concentration Siricc the G::'E SySten'i was Sl'tut down. Gasoline constituent concentrations remain low or below laboratory detection limits in all wells at this site. We recommend leaving the GWE system shut down and continued groundwater monitoring at this site. We also recommend a reduction in the sampling frequency of selected wells. Many of the wells at this site have historically had low or non-detectable levels of gasoline constituents. Quarterly sampling of these wells is not warranted. We recommend that wells MW-2, MW-3, MW-5A, MW-5B, and MW-6B be sampled annually in the second quarter of each year. We will implement this change in sampling frequency once we have received approval from SJCPHS. We recommend that water level measurements in all site wells continue on a quarterly basis. ANTICIPATED SECOND QUARTER 2002 ACTIVITIES Blaine will gauge and sample all wells and tabulate the data. Cambria will prepare a groundwater monitoring report. 0324 2