SITE INFORMATION AND CORRESPONDENCE

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Sent By: RWOCB SACRAMENTO; ; pr- - ; - 2 - California 2 -Calif is Water Servire SuRglyWells Five supply wells have been constructed by CWS within 3,000 feet of the site(the Department of Water Resources only has well logs for four). In conversations with a CWS representative and review.of the DWR well logs,the following information regarding these wells was obtained: • Well located about 2,700 feet to the south: TD-560 feet;seal-264 het bgs;status-well destroyed(date unknown)- • Well located about 2,500 foot to the north: TD-535 feet;seal- m*nown; status-well destroyed(date unknown). • Well located about 2,200 feet to the north: TD-563 feet;seal-72 feet Ings;status-backup. • Well located about 1,800 feet to the west: TD-550 feet;seal-225 fed bgs;status-well destroyed in 1988. • Well located about 800 feet to the noethinortheast: TD 400 feet;seal-96 feet bgs;status- emergency backup. With regard to the last well.CWS took it Out of service in 1991 because of a"sanding"problem. Additionally.the water produced by the well at that time had a reported chloride consultation of 240 ppm. CWS has indicated that it has no intention of using this well for municipal Stpply purposes and intends to use it only in the cveat of a locd d7xsasW_o_r_MF High congggtations afp=leum constftuerits idgatfiad rcoflfiMLqd!I in soil an(i&Mundwater over 150 fcct_offsitF. This conciusivn has no basis ' There are five offsite data points: monitor wells MW-4, MW-5,MW-7,MW--8, and MW-9. Well MW-4 is located about 85 fed down-gradient of the site; MW-5 is located about 70 feet down-gradient; and MW-7 is located about 290 feet down-gradient. Monitor wells MW41 and MW-9 are less than 45 feet up-gradient and cross- gradient. respectively, of the site. Water quality data collected over the past two years from wells MW-4 and MW-5 show that benzene concentrations have ranged from less than 0.5 ppb to 1.0 ppb;concentrations of TPHg have ranged from less than 50 ppb to 140 ppb. Concentrations of TPHg and benzine have each been detected in well MW-7 once: TPHg at 98 ppb in March of 1992,and benzene at less than I ppb in February or 1 19. Concentrations of TPHg reported for soil samples collected in August of 1989 from the borings for wells MW-4 and MW-5 were 150 ppm and 240 ppm, respectively;concentrations of benzene were not detected. No petroleum hydrocarbon constituents were detected in soil samples collected during the drilling of well MW-7 in February of 1992. California Environmental Protection Agency R PqW