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wildlife, and other aquatic resources. The beneficial uses of groundwater <br /> in this area are domestic, municipal , industrial , and agriculturol supply. <br /> 4. 1.4 The Department of the Army (previously the War Department) has <br /> operated the Depot as a general supply, storage, and maintenance facility <br /> since 1941. SHAD uses, or has used at the Depot, various chlorinated <br /> solvents, paint, thinner, pesticides, and organic solvents for facility and <br /> supplies maintenance. <br /> 4.1.5 SHAD presently discharges up to 0.38 million gallons per day of <br /> secondarily treated domestic waste water (governed by NPDES permit No. <br /> 78-214) to the South San Joaquin Irrigation District drainage canal east of <br /> the Depot. In the past, SHAD has also discharged treated industrial wastes <br /> to the drainage canal and disposed of liquids, sludges, and solids, includ- <br /> ing chlorinated volatile organics, to land on the Depot. <br /> 4. 1.6 Since 1980, SHAD has been conducting an environmental assessment <br /> which has included the installation of in excess of 160 wells on and around <br /> the Depot at various depths, over 1800 soil gas samples, soil sampling, <br /> geophysical investigations, and well sampling and analysis. Sample results <br /> from these wells show that the shallow aquifer in both the southern and <br /> northern portions of the Depot is contaminated with chlorinated volatile <br /> organics, primarily trichloroethylene (TCE) up to 1245 parts per billion <br /> (ppb) ( in the southern portion of the Depot) and arsenic up to 720 ppb ( in <br /> the southern portion of the Depot). Pollutants exceeding state action lev- <br /> els extend to depths of over 140 feet on the Depot. Monitoring wells <br /> off-Depot have been installed beginning in 1985, and results show that TCE <br /> contamination downgradient of the Depot extends to a depth of 140 feet at <br /> -9- <br />