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Closure Report T
<br /> Golden Grain Manteca Bean Facility,299 Moffat Boulevard,Manteca,California July 16,19%
<br /> lower sand zone, had 11,000 ppb TPH-g and 2,600 ppb benzene Therefore, hydrocarbon
<br /> concentrations decreased by an order of magnitude from the upper to the lower sand-zone Trace
<br /> levels of ethylene dibromide (EDB)were detected in groundwater samples from wells MW-2, MW-5,
<br /> and MW-7, at 42 jug/L, 1 6,uglL, and 5 7 mg/L, respectively Concentrations of organic lead were not
<br /> detected in groundwater at this time The results of the June 12, 1990, sampling event are reported
<br /> in the August 10, 1990, quarterly report(Groundwater Technology 1990a) Historic groundwater
<br /> analytical results are summarized in table 5
<br /> 1 2.2 3 One-Half Mile Well Survey, BeneFcial Uses, Groundwater Objectives
<br /> State of California, Department of Water Resources records were reviewed in 1987 during the
<br /> ' assessment phase of the protect and indicated there were five municipal water-supply wells (1, 2,
<br /> 3, 5, and 7), operated by the City of Manteca,within one-half mile of the site (figure 14)
<br /> Monitoring, domestic, and imgation wells were Identified during the survey, but they are located
<br /> ' outside the one-half mile radius Table 6 provides a summary of the well survey According to the
<br /> well survey, municipal wells 1, 2, and 5 are closest to the site Wells 1 and 2 are located
<br /> approximately 800 feet west of the site, in a location that is across and upgradient of the site Well
<br /> 5 is located approximately 2,000 feet west of the site, also across and upgradient of the site The
<br /> closest downgradient well is municipal well 3, located approximately 2,000 feet slightly northeast of
<br /> ' the site Municipal well 7 is located approximately 2,500 feet southeast of the site in an across
<br /> gradient direction
<br /> Mr Jim Podesta of the City of Manteca was contacted on July 5, 1996, and confirmed that no new
<br /> municipal water supply wells have been installed within the one-half mile radius of the site since
<br /> 1987 and no wells are currently planned The existing municipal wells range In total depth from 140
<br /> feet to 382 feet According to the City of Manteca Department of Public Works, the depths of the
<br /> ' seals In all municipal wells are reported to be greater than 100 feet Given the locations of the above
<br /> listed wells in relation to the site, prevailing groundwater gradient, and the data concerning the well
<br /> seals, there is no significant risk to the water supplies serviced by these wells
<br />� r
<br /> Review of the Basin Plan for the California RWQCB, Central Valley Region, Indicates that the site is
<br /> located between basin 5A (Sacramento/San Joaquin Delta Basin and basin 5C (Sart Joaquin River
<br /> Basin) The principal source of groundwater in these basins is the San Joaquin-Tulare Valley Aquifer
<br /> System Beneficial uses for groundwater in these basins have been designated as municipal and
<br /> ' domestic, imgation, stock watering, and service supply
<br /> FLUOR DANIEL GTI
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