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Release Date: 7/30/2001
Contact Information: Leo Kay, Press Office, 415/744-2201

     Plan will stem migration of contamination headed toward drinking water wells

     SAN FRANCISCO   The U.S. Environmental Protection Agency recently finalized its $111 million  plan for containing and remediating contaminated groundwater beneath the western side of the Aerojet Superfund Site outside of Folsom, Calif.

     Nine water supply wells have been lost to groundwater contamination emanating from the Aerojet Site, and an estimated 13 additional public water supply wells could be lost over the next 25 years if the contaminated groundwater is not contained and remediated.  The groundwater is contaminated with several compounds, including very high levels of perchlorate a suspected human carcinogen and known developmental toxin.

     "This innovative cleanup will prevent the contaminated groundwater from fouling any additional water sources," said John Kemmerer, deputy director of the EPA's Superfund program in San Francisco.  "In particular, this plan sets the most protective cleanup standard ever set for perchlorate, a compound that has contaminated almost 200 drinking water supplies across the state. We are going to reduce perchlorate levels in the groundwater from the current level of 8,000 parts per billion to four parts per billion, the lowest concentration we can measure."

     The Environmental Working Group recently issued a report calling for a national cleanup standard for perchlorate in drinking water of 4.3 parts per billion.

     The EPA evaluated 10 options for addressing the contaminated groundwater before deciding on the current plan.  The EPA selected its preferred alternative over the next best proposal because it  will restore the aquifer in 240 years as opposed to 348 years.

     The main components of the EPA's plan are:
          Contain contaminated groundwater off-property on the western side of the site with pump and treat in all contaminated layers of the aquifer to prevent further contamination;

          Contain contaminated groundwater at the property boundary (which is feeding the off-property groundwater contamination) with pump and treat;

          Restore all layers of the aquifer between the on- and off-property extraction systems to their uses as drinking water aquifers;

          Treat the extracted groundwater using biological treatment for perchlorate, ultraviolet oxidation for NDMA (another by-product of rocket fuel) and air-stripping for residual VOCs;

           Make the treated water available for local water use as replacement for water already los due to the groundwater contamination; and  

          Provide for short-term and long-term water replacement contingency plans to replace any more loss of water supply wells.

     Aerojet can discharge the treated water to Folsom Canal, American River, Lake Natoma, Buffalo Creek or Aerojet can keep and use the treated water.

     The EPA selected the final plan after holding a 60-day public comment period to solicit input on its preferred alternative.
                        Site Background

     Since 1953, Aerojet and its subsidiaries have manufactured rocket engines for military and commercial applications, using rocket propellant agents, agricultural, pharmaceutical, and other industrial chemicals. Unknown quantities of hazardous chemicals were disposed of throughout the site in surface impoundments, landfills, deep injection wells, leachate fields, and through open burning.  The EPA designated the 8,500-acre site a Superfund site in 1983 after perchlorate, VOCs and other compounds were found off site in private wells and in the American River.