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KEI-P88--1013 .R4
<br /> October 27 , 1994
<br /> Page 3
<br /> KEI concluded that both the source of the contamination and the
<br /> majority of the contaminated soil had been removed from the site,
<br /> and that it was necessary to determine the extent of ground water
<br /> contamination. It was also concluded that KEI would prepare
<br /> proposals, as necessary, for well repass and abandonment, installa-
<br /> tion of additional monitoring wells, and subsequent ground water
<br /> remediation (if warranted) .
<br /> On November 29 , 1988, an attempt was made to obtain ground water
<br /> samples from the then existing monitoring wells . However, most of
<br /> the wellheads were found to be damaged during soil excavation.
<br /> Wells MW2 , MW3 , MW4 , MW5, and MW9 were in need of repair. Although
<br /> damaged, access was gained to most of the wells. Wells MW4 , MW6,
<br /> MW8 , and MW9 were essentially dry, whsle only 2 . 5 to 6 . 4 gallons of
<br /> water could be purged from MW2 , MW3 and MW5 Based on the lack of
<br /> rainfall and the subsequent drop in elevation of the ground water
<br /> table at the site, it was decided by Unocal and KEI to attempt to
<br /> sample the wells later in the winter.
<br /> On February 24 , 1989, an attempt was again made to sample as many
<br /> existing monitoring wells as possible. Only wells MW2 , MW3 , MW4 ,
<br /> and MW5 were sampled. Monitoring well MW6 was dry, MW8 contained
<br /> approximately one to two gallons of water and did not recharge
<br /> sufficiently to be sampled after purging, and MW9 was covered with
<br /> soil (prior to excavation, MW9 had also been dry) .
<br /> Water samples were collected from wells MW2 , MW3 , MW4 , and MW5 on
<br /> February 24 , 1989 . The water samples were analyzed at Sequoia
<br /> Analytical Laboratory in Redwood City, California, for total
<br /> petroleum hydrocarbons (TPH) as gasoline, benzene, toluene,
<br /> ethylbenzene, and xylenes (BTEX) , and EPA method 601 constituents.
<br /> The analytical results are summarized in Table 3 . The results of
<br /> the first and only quarter of monitoring and sampling of these
<br /> wells performed by KEI are presented in KEI ' s report (KEI-P88-
<br /> 1013 .QR1) dated March 17 , 1989 .
<br /> On March 14 , 1989 , a well survey was conducted at the Department of
<br /> Water Resources in Sacramento. Approximately 40 wells were found
<br /> within a one-mile radius of the site, the closest well (that could
<br /> be accurately located) was situated 2 , 000 feet to the northwest.
<br /> In addition, Kleinfelder previously reported an agricultural well
<br /> (located approximately 1/4 or 1/2 male southwest of the site) at
<br /> Delta College, which appeared to influence the ground water flow
<br /> direction and gradient in the shallow monitoring wells at the
<br /> Unocal site. The results of KEI ' s well survey are summarized in
<br /> Table 6, and the locations of the wells are shown on the attached
<br /> Well Location Map, Figure 5 .
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