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• Groundwater Gradient Groundwater elevations were plotted to a known datum to prepare a groundwater contour map The groundwater flow direction was toward the north-northeast at sampling time, and a flow gradient of 0 033 was calculated Water levels have dropped roughly 0 3 feet, and this decline is normal aquifer discharge Historic groundwater flow trends typically vary from north- northeasterly to north-northwesterly Chemical Analysis and Results The samples were transported to Chromalab, Inc in Pleasanton, CA The groundwater samples were analyzed using EPA Methods 5030/ 8015 and 602 for Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) and fuel oxygenates including Methyl-tert-butyl-ether (MTBE) by EPA Method 8260 The analytical reports are attached, and the results are listed below in Table 2 (see Table 3 for historic data) Table 2 Groundwater Chemical Data Well No Date TPHG` Benzene Toluene Ethylbenz Xylene Fuel Ox ------------------------------- u g/1 ----------------------------- MW-1 6/30/98 9,100 860 150 1,000 940 NO MW-2 6/30/98 NO ND NO ND NO NO MW-3 6/30/98 ND NO NO ND NO ND MW-4 6/30/98 ND NO ND ND NO NO Blank 6/30/98 NO NO ND NO NO NO NO - None detected NA - Not Analyzed ug/1 - micrograms per liter Fuel Ox - Fuel oxygenates by Method 8260 Discussion Groundwater flow direction appears consistent with historically observed trends The concentrations in Well MW-1 similar to the previous quarter and are attributed to residual contaminants desorbing into the groundwater from the soil strata in the immediate vicinity of the former tank pit MTBE was not detected in any well Well MW-4 showed contaminants not detected Conclusions and Recommendations The PHS-EHD has requested that bids be solicited for the Wright recommended soil excavation in the immediate tank pit area, as well as a well search this information will be used to remove residual contaminants in order to attain site closure in the future Wright recommends that the quarterly monitoring for this site continue at quarterly intervals It is our understanding that the San Joaquin Valley RWQCB has requested that all fuel oxygenate compounds be chemically analyzed by EPA Method 8260 in the future for fuel release sites, and Wright will continue the Page 3