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. Mr. Steve Sasson Project 22794-100.001 <br /> August 10, 1998 <br /> Page 10 <br /> during site assessments and does not include a potential mass reduction by <br /> biodegradation <br /> • The site has been adequately characterized. <br /> — During subsurface assessment activities conducted between 1987 and 1995, a <br /> total of 36 exploratory borings were drilled HydroPunch groundwater <br /> samples were collected from 15 of the borings Six borings were converted to <br /> groundwater monitoring wells. Three groundwater monitoring wells (MW-1, <br /> MW-2,and MW-3)were decommissioned in 1991. <br /> — Eight groundwater monitoring events were conducted in between 1992 and <br /> 1995. TPHD concentrations in samples collected from wells MW-4, MW-5, <br /> and MW-6 ranged from 150 to 1,200 mg/L. BTEX constituents were not <br /> detected Analysis for PNAs was conducted as part of the March 1995 <br /> monitoring event The sample collected from MW-6 contained phenanthrene <br /> (0.95 µg/L), anthracene(7 7 µg/L), and pyrene (0.038 µg/L). <br /> ® The dissolved plume is not migrating and levels are not consistently above <br /> MCLs. <br /> - Statistical evaluation of the detected TPHD concentrations in groundwater <br /> monitoring well samples did not identify statistically significant trends for <br /> TPHD concentrations in groundwater samples collected from monitoring <br /> wells MW-4, MW-5, and MW-6 between 1992 and 1995 The absence of <br /> concentration trends suggests the plume is stable and the dissolved <br /> hydrocarbon mass is not increasing. <br /> • No water well, deeper drinking water aquifers, or other sensitive receptors are <br /> likely to be impacted. The site represents no significant risk to human health and <br /> safety. <br /> Western Geologic Resources, Inc., conducted the well survey in 1990• <br /> Thirteen wells were reportedly identified within 1/2 mile of the site. Eleven <br /> wells are used for industrial purposes and two wells are used for domestic <br /> purposes Safeway's March 1996 report included an updated well survey <br /> Four other wells were identified that produce groundwater for municipal and <br /> domestic purposes. The municipal well is Cahfornia Water Service Pumping <br /> Station No. 72 and has been out of service since 1978. Information presented <br /> in the report attributed to California Water Service cites high TDS and <br /> Mon <br /> SATJ2�2794�2794 LOGO ICS-9"s mera <br /> ax <br /> Rev a s�iO�9s <br />