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ATC Associates Inc. <br /> 1117 Lone Palm Avenue,Suite 201 <br /> "kT <br /> Modesto ax:afornia 95351 <br /> 209-5792225 <br /> A S S Oe l A T E 6 INC . <br /> directional groundwater flow. Groundwater in the vicinity of the site is expected to coincide with the <br /> regional northeasterly gradient. Three domestic water wells were observed within 500 feet northeast of <br /> the site.A fourth domestic well was observed within 500 feet north,northeast of the site.The following is <br /> a summary of information pertaining to wells located within an approximate radius of 500 feet fiom the <br /> site. <br /> Tobje 33 Summary of Water Well Information Within Approximately 500 Feet of the Site <br /> Map Approximate Listed or Year Casing Depth to Top Depth to Bottom <br /> ID Distance&Direction Assumed Drilled Diameter of Perforation of Perforation <br /> From Site Use inches <br /> 1 400'West Irrigation 1973 12 194 254 <br /> 2 500'North Domestic Unknown Unknown Unknown Unknown <br /> 3 400'North Domestic Unknown Unknown Unknown Unknown <br /> q 490'North Domestic 1986 6 122 152 <br /> 5 200'Northeast Domestic 2002 6 200 252 <br /> 6 490' East,Northeast Domestic Unknown Unknown Unknown Unknown <br /> 7 400'East Northeast Domestic Unknown Unknown Unknown Unknown <br /> g 200' Southeast Domestic Unknown Unknown Unknown Unknown <br /> 9 450' South,Southeast Domestic Unknown Unknown Unknown Unknown <br /> 10 490' South Domestic Unknown <br /> Unknown Unknown Unlmown <br /> 11 500' South Domestic Unknown Unknown Unknown Unknown <br /> 12 250' South Domestic I Unknown I Unlmown Unknown Unknown <br /> 13 450'Southwest Domestic I Unknown Unhnown Unknown Unknown <br /> Unknown indicates well was observed but corresponding well log was not provided by DWR <br /> 7.0 LOW RISK CLOSURE CRITERIA <br /> Criterion 1: The source of the UST release has been identified and removed. <br /> The former UST system which was removed in 1995 appears to have been the source of the <br /> release.Data collected from the site do not suggest a release from other sources. <br /> Criterion 2: The vertical and horizontal extent of subsurface impact has been adequately <br /> characterized. <br /> The majority of impacted soil appears to have been removed during the 1995 excavation effort. <br /> Some residual impacted soil may be present below the eastern edge of the garage building at <br /> depths ranging from approximately 10 to 25 feet bgs. TPHg was detected at concentrations of 32 <br /> mg/kg, 51 mg/kg, 1,300 mg/kg, and 530 mg/kg in soil samples collected from JLM2 at depths of <br /> 10, 15, 20, and 25 feet bgs, respectively, in 2001. Low concentrations of ethyl benzene and total <br /> xylenes were also detected in these samples. Petroleum hydrocarbons were not detected in <br /> samples collected from JLM2 at depths of 30 and 35 feet bgs. These concentrations may have <br /> subsequently diminished as a result of natural attenuation. <br /> S:EnviromnentaIU8589\Repoas\Closure Report.doc 13 <br />