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Site History 14000 Highway 88,Lockeford CA Time Oil Property No 04-049 overall average decrease in groundwater elevation of 0 23 feet across the site Changes In groundwater elevation are most likely a result of seasonal variation Groundwater gradient and flow direction remained consistent with previously collected data Analyses identified elevated concentrations of hydrocarbons In the samples collected from MW-1 (2,780 ppb gasoline, 97 ppb benzene, 96 ppb toluene, 216 ppb ethylbenzene, 163 ppb xylenes), MW-2 (515 ppb gasoline, 5 2 ppb benzene, 1 0 ppb toluene, 0 8 ppb ethylbenzene, and 43 8 ppb xylenes), MW-3 (306 ppb gasoline, 28 3 ppb benzene, 11 7 ppb toluene, 10 1 ppb ethylbenzene, and 26 5 ppb xylenes), MW-4 (1,810 ppb gasoline, 300 ppb benzene, 3 9 ppb toluene, 151 ppb ethylbenzene, and 7 1 ppb xylenes), and MW-5 (4,050 ppb gasoline, 395 ppb benzene, 22 ppb toluene, 177 ppb ethylbenzene, and 608 ppb xylenes) Lower concentrations of hydrocarbons were found in the samples collected from MW-6 (73 ppb gasoline, 5 2 ppb benzene, 0 8 ppb ethylbenzene, and 5 3 ppb xylenes), MW-8 (78 ppb gasoline and 0 9 ppb benzene) and MW-9 (91 ppb gasoline and 2 0 ppb benzene) Hydrocarbons were not detected in the samples collected from MW-7 and MW-10 Low concentrations of MTBE were detected in the groundwater sample collected from MW-4 (25 8 ppb), however, it was not detected In any of the other samples The highest concentrations of hydrocarbons appear to remain onsite in the vicinity of the pump Islands (MW- 1) and sidegradient of the former tank bed (MW-5) When compared to the January 1999 sampling event, hydrocarbon concentrations decreased In MW-1 and MW-2 while they decreased in MW-4 and MW-5 Hydrocarbon concentrations remained relatively unchanged in each of the wells A copy of SECOR's "Quarterly Monitoring Report, April - June 1999" dated July 28, 1999, was forwarded to the appropriate regulatory agencies on August 2, 1999 24