SITE INFORMATION AND CORRESPONDENCE_1993-2003

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• Continued from previous page Glossary of Terms: Update on Sharpe's Installation Restoration Program (IRP) Arsenic-A naturally occurring metal. In Background: In 1979, the Department of Defense established an its inorganic form, arsenic is listed as a IRP at Sharpe. The IRP ensures that Sharpe studies and cleans up cancer-causing chemical under the environment in accordance with the federal law known as California's Proposition 65. CERCLA, or Superfund. The following regulatory agencies provide oversight to Sharpe's IRP: Bromacil-A herbicide used in agriculture. Bromacil can be toxic at • U.S. Environmental Protection Agency (U.S. EPA) higher levels. • State of California Dept. of Toxic Substances Control (DTSC) • State Water Quality Control Board's Central Valley regional office CERCLA - Comprehensive (CVRWQCB). Environmental Response, Compensation, and Liability Act- These agencies work with Sharpe to set cleanup goals and Commonly referred to as "Superfund," determine the best cleanup techniques to use at the depot. CERCLA is a federal law that was passed in 1980 and modified in 1986 to Environmental Concerns and Cleanup Systems at Sharpe: After provide funding and enforcement completing many investigations, Sharpe identified sites where authority for the cleanup of hazardous potentially harmful chemicals were present in depot soils and waste sites. groundwater (groundwater is water that moves beneath the Chromium-A naturally occurring ground's surface). metalllevels. chemical that is toxic at higher The following chemicals have been found in the groundwater at Sharpe: Lead-A naturally occurring heavy • The cleaning solvents trichloroethene(TCE) and metal. Lead and its compounds are tetrachloroethene(PCE) listed as cancer-causing substances • Total petroleum hydrocarbons (TPH) under California's Proposition 65. • Selenium and arsenic in amounts that have degraded groundwater but are believed to have come from natural deposits Selenium-A naturally occurring or from sources unrelated to activities at Sharpe element that is nutritional at lower levels • Very small amounts of the herbicide bromacil but toxic at higher levels. TCE is the chemical of greatest concern at Sharpe because it is Tetrachloroethene (PCE)- (Also present in the greatest amounts. TCE and, to a lesser extent, PCE known as perchloroethene, or 'perc.') are found in groundwater that is moving from the depot in a A volatile organic compound commonly northwesterly direction. used as an industrial degreasing solvent. At Sharpe, PCE was used to Sharpe has installed three groundwater treatment systems to clean machine parts. PCE is toxic and control the movement of TCE and PCE in groundwater (the ulisted as a cancer-causing chemical photograph on page 1 shows one of these treatment systems). under California's Proposition 65. These systems use a technique called air stripping to remove the Trichloroethene (TCE)-A volatile harmful chemicals from the groundwater beneath Sharpe. The organic compound commonly used as clean water is then released into the South San Joaquin Irrigation an industrial degreasing solvent. At District Canal. Sharpe, TCE was used to clean machine parts. TCE is suspected to The following chemicals have been found in the soil at Sharpe: cause cancer in laboratory animals. TCE, TPH, lead, and chromium. Total Petroleum Hydrocarbons (TPH) During the past ten years, most of the contaminated soil at Sharpe -A large group of chemicals that make has been excavated, removed, and disposed in a permitted up oils, gasoline, and diesel. Fuels hazardous waste disposal facility. used at Sharpe contained TPH. TPH can be toxic if inhaled or ingested. For the TCE that remained in the soil, Sharpe used a technique called soil vapor extraction (SVE) to vaporize the TCE and collect 2