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6.2 Offsite Receptors — Water Supply Wells Two surveys of water supply wells in the vicinity have been performed. Emcon identified six water supply wells located within a 2,000-foot radius of the site. A consultant for the Del Monte Plant 33 on Filbert Street (located approximately 3,000-fect southeast of the former Apache Plastics facility) identified two water supply wells located within 2,000 feet of the former Apache Plastics facility. Available well information, and a figure illustrating the locations of these wells, is included in Appendix D. The locations and operational status of the wells identified in these surveys have not been verified. Emcon Survey: Two wells were identified within 500 feet of the site by the Emcon survey; an industrial supply well approximately 300 feet to the west-southwest (Emcon map ID #4), and a well of unknown usage situated approximately 450 to the east-northeast (Emcon map ID #2). These wells appear to be cross-gradient of the Apache site. An industrial well was identified approximately 1,800 feet to the southeast. Historical groundwater flow data indicate that this well is downgradient of the Apache site. However, given the apparent characterization of the downgradient extent of dissolved hydrocarbons, this supply well does not appear to be immediately threatened. . Del Monte Survey: The Del Monte survey identified a municipal supply well operated by California Water Service (Del Monte Map ID 95) approximately 500 feet east of the Apache Plastics site. The Del Monte information indicates that this well was installed in 1943 and deactivated in 1978. Based on similar installation dates and locations, this may be the same as the well identified as Emcon Map ID #2. The Del Monte survey also identified a water supply well in the vicinity of A Street and I Ith Street (Del Monte Map ID #23). This well is situated approximately 2,000 feet southwest of the Apache site. Based on historical flow data, these wells do not appear threatened. 6.3 Utilities All utilities are delivered to the former Apache Plastics building via subsurface routes. There are no on-site septic or water disposal systems operated at this site. Given historical depth to water data for this site, it appears unlikely that subsurface utility trenches act as preferential pathways for hydrocarbon migration. It might be possible, however, for vapors from the COCs, at depth, to accumulate in the utility trenches. Construction workers excavating these utilities could potentially be exposed to CDCs via this route. Similarly, if there are any subsurface manholes/vaults associated with these utilities, CDCs could accumulate in the vaults. Given the depth to dissolved hydrocarbons, this exposure pathway appears unlikely. i p;\Apache PlasticMeports\Apache SCM.doc Page 13 Stratus