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r Page 3 <br /> • Mr Michael Infurna Jr,Senior REHS <br /> February 8,2001 <br /> pH, and electrical conductivity parameters were also measured during the purging <br /> process to assess groundwater stability. Purged groundwater was placed in one <br /> 55-gallon drum,which is temporarily stored on-site pending proper disposal <br /> Groundwater samples were collected from each well with its own dedicated <br /> bailer. The samples were placed in clean, laboratory-provided glass containers, <br /> sealed,labeled, and stored in an insulated iced chest The samples were delivered <br /> to Acculabs, Inc laboratory in Davis, California, accompanied by cham-of- <br /> custody documentation, for chemical analysis Samples were analyzed for BTEX <br /> and TPHg compounds using EPA Method 602/8015 Samples were also analyzed <br /> for the oxygenate compounds tert-butanol (TBA),methyl-tert-butyl ether <br /> (MTBE), di-isopropy ether (DIPE), ethyl-tert-butyl ether(ETBE), and tert- <br /> amylmethyl ether (TAME)using EPA Method 8260B <br /> Groundwater Level Measurements <br /> As shown in Table 1 (Attachment 2), groundwater within the monitoring wells <br /> were measured at depths approximately 0 2 to 0 4 feet lower than the previous <br /> round of monitoring performed in October 2000 Groundwater depths ranged <br /> from 24 47feet (below the top of the well casing) to 25 00 feet The corresponding <br /> groundwater elevations, evaluated during this monitoring period, ranged from <br /> minus (-)13 47 feet to—13 73 feet relative to mean sea level As shown in <br /> Figure 3, groundwater flows southeasterly at an approximate gradient of <br /> j2 13 x 10" feet per foot. <br /> Groundwater Sample Analytical Results <br /> Petroleum hydrocarbon concentrations were detected in the groundwater samples <br /> collected this quarter from monitoring wells MW-1 and MW-2 (see Table 2) <br /> However,the concentrations measured in the MW-1 sample are relatively trace <br /> amounts compared to those measured in the MW-2 sample <br /> Petroleum hydrocarbon concentrations in the current MW-2 groundwater sample <br /> are similar (within an order of magnitude)to the initial sample collected from this <br /> well in July 1999 Benzene and TPH-g concentrations in the current MW-2 <br /> sample were measured at 16,000 micrograms per liter(ug/1) and 110,000 ug/l, <br /> respectively (see Figure 4 and Figure 5). Current toluene, ethylbenzene, and <br /> xylenes concentrations in the MW-2 sample are also comparably similar <br />