Aerojet Treating Groundwater After Perchlorate Detected In Local Wells

After small amounts of perchlorate were detected in nine drinking wells just west and southwest of Aerojet's Rancho Cordova, CA-site, the Company has dedicated a $5 million groundwater treatment facility to eliminate a potential health risk to the local population.

"Although we don't know yet if perchlorate in the amounts detected outside our fence poses a health risk, Aerojet is committed to preventing further migration of the chemical," said Suzanne Phinney, vice president of Environmental, Health and Safety for Aerojet.

After perchlorate was detected, the U.S. Environmental Protection Agency closed the wells as a precaution until it can determine what levels are safe. Over the years, perchlorate, which is used as an oxidizer in solid rocket propellant, has washed into the ground at the Aerojet site during propellant processing and leached into groundwater.

The Company, in conjunction with local and state regulators, is continuing to monitor groundwater perchlorate levels on and off its property. The perchlorate treatment facility uses microbes that feed on perchlorate (CLO4) and break it down into harmless chloride (salt) and oxygen atoms. Groundwater beneath Aerojet's southwestern boundary is diverted to the plant, cleansed of perchlorate, and then put back into the groundwater aquifer. Phinney explained that, "at 4,000 gallons per minute, this plant will remove perchlorate from the groundwater beneath Aerojet and eliminate a potential major health concern for nearby residents."

Questions about the possible hazards of perchlorate have arisen primarily from observations of hyperthyroidism patients who were prescribed perchlorate to treat overactive thyroids. While successful in reducing thyroid hormone production, such treatments resulted in some side effects and also raised the issue of perchlorate's effect on people with normal thyroids. The Department of Health Services set a provisional safe drinking water level for perchlorate at 18 ppb. The nine drinking wells closed outside Aerojet all exceeded this level by varying amounts.

Aerojet has helped form a national Perchlorate Study Group, composed of manufacturers and users, to work with the Department of Defense to support the EPA in determining a more accurate safe level for perchlorate in groundwater. The EPA's reference dose is expected to be announced this winter.

For more information: Julie A. Rovegno, Communications Manager, Aerojet, P.O. Box 13222, Sacramento, CA 95813. Telephone: 916-355-4904. Fax: 916-351-8667.