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KEI-P88-1013 .R2 July 15, 1992 Page 3 repair. Although damaged, access was gained to most of the wells. Wells MW4 , MW6, MW8 , and MW9 were essentially dry, while only 2 . 5 to 6 . 4 gallons of water could be purged from MW2 , MW3 and MW5. Based on the lack of rainfall and the subsequent drop in elevation of the ground water table at the site, it was decided by Unocal and KEI to attempt to sample the wells later in the winter. On February 24 , 1989 , an attempt was again made to sample as many existing monitoring wells as possible. Only MW2 , MW3 , MW4 , and MW5 were sampled. MW6 was dry, MW8 contained approximately one to two gallons of water and did not recharge sufficiently to be sampled after purging, and MW9 was covered with soil (prior to excavation, MW9 had also been dry) . During monitoring, wells MW2 , MW3 , MW4 , MW5, and MW8 were checked for depth to water and presence of free product and sheen. After monitoring, the wells were purged and allowed to recover (MW8 did not recover) . No free product or sheen was noted in any of the wells. Water samples were collected from wells MW2 , MW3 , MW4 , and MW5 on February 24 , 1989 . The water samples were analyzed at Sequoia Analytical Laboratory in Redwood City, California, for total petroleum hydrocarbons (TPH) as gasoline, benzene, toluene, xylenes and ethylbenzene (BTX&E) , and EPA method 601 constituents. The analytical results showed non-detectable levels of BTX&E in wells MW3 , MW4 and MW5 . In well MW2, the benzene level was 54 ppb, and 1, 2--dichloroethane was 440 ppb. The results of the analyses are summarized in Table 2 . The results of the first and only quarter of monitoring and sampling of these wells performed by KEI are presented in KEI ' s report (KEI-P88-1013 .QR1) dated March 17, 1989 . During the extensive excavation that occurred at the site, much of the asphalt was removed. Because the asphalt was removed and the monitoring well covers had all suffered some damage during soil excavation, the original datum elevations were no longer valid for all the wells. Water table elevations measured in MW2 through MW5 (the only wells from which water samples could be collected on February 24 , 1989) suggested a relatively flat gradient. The gradient was inferred to be south-southwest toward the Calaveras River and Quail Lake. On March 14 1989 well information was obtained at the Department of Water Resources in Sacramento. Approximately 40 wells were found within a one--mile radius of the site, the closest well (that could be accurately located) was located 2 , 000 feet to the north- west. In addition, Kleinf elder previously reported an agricultural _ well (located approximately 1/4 or 1/2 mile southwest of the site) at Delta College, which appeared to influence the groundwater flow direction and gradient in the shallow monitoring wells at the