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i <br /> � 1 <br /> CAMBRIA <br /> MTBE in groundwater beneath the site has been detected at increasing concentrations <br /> predominantly in upgradient wells. The USTs at the subject site were removed in 1981 prior <br /> to any known use of MTBE in gasoline in California. The increasing levels of MTBE suggest <br /> a recent or active release, which is not possible from the subject site as it has been non- <br /> operational since 1981. We reviewed historical groundwater analytical data for this site and <br /> saw a trend in the MTBE data that indicates an MTBE plume is migrating across the site <br /> from west to east. We prepared concentration versus time graphs for three of the wells at <br /> the subject site. These wells, MW-5, MW-1, and VEW-4, in general, run from west to east, <br /> respectively, across the subject site. Groundwater flow direction at the subject site has <br /> predominantly been toward the east. The graphs show MTBE first appears in the most <br /> westerly well (MW-5). At a later date MTBE is seen in well MW-1, and later in well VEW-4. <br /> This trend suggests a plume of MTBE migrating from west to east across the subject site from <br /> an offsite source. <br /> Furthermore, the former Arco site, located upgradient and at the western end of Channel <br /> Street, approximately 300 feet from the subject site, recently had offsite wells installed to <br /> delineate the lateral extent of their MTBE plume. At this point it is unknown where Arco's <br /> MTBE plume has migrated. <br /> Equiva intends to have Cambria submit a formal case closer request for the subject site soon. <br /> WORKPLAN <br /> Presented below is a work plan for the proper destruction of all monitoring wells, vapor <br /> extraction wells, and groundwater extraction wells located at the subject site. <br /> Permits <br /> An appropriate permit for well destruction will be obtained from SJCPHS. <br /> Health and Safety Plan <br /> A site-specific Health and Safety Plan will be prepared for field work. <br /> Utility Clearance <br /> Proposed drilling locations will be marked and their locations cleared through Underground <br /> Service Alert (USA) prior to drilling. <br /> 0821 2 <br />