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PerchlorateEPA has released for public review and comment its revised draft toxicity assessment on perchlorate, which is the primary ingredient of solid rocket propellant. The draft assessment, entitled "Perchlorate Environmental Contamination: Toxicological Review and Risk Characterization," is available at www.epa.gov/ncea under "what's new". The Agency will also hold a peer review workshop open to the public on this draft assessment on March 5th and 6th 2002, in Sacramento, California. This meeting will be open to the public, and more information is available at www.epa.gov/fedrgstr under the heading for Jan. 2. Following this opportunity for public and independent scientific input, EPA expects to finalize the document by late summer, 2002. When finalized, this draft assessment will be an important update to the Agency's health and ecological assessment for potential risks resulting from exposure to perchlorate through drinking water and other sources. The revised human health and ecological risk estimates found in this draft document continue to undergo scientific review and analysis both within EPA and by the external scientific community. As with any draft EPA assessment containing a quantitative risk value, risk estimates in this review document are preliminary. Therefore, it is premature at this stage to interpret risk estimates in this draft document as final EPA conclusions on which the Agency could take risk management action. The draft risk estimate is not a drinking water standard, but is the first step in a lengthy process to determine if the agency should set a federal drinking water standard for this contaminant. EPA, other federal agencies, states, water suppliers and industry are already addressing perchlorate contamination through a number of activities. EPA is monitoring for perchlorate in drinking water through the Unregulated Contaminant Monitoring Program and the U.S. Geological Survey is monitoring for perchlorate in surface water. In California, Superfund sites are employing new technologies to remove perchlorate from contaminated water. The Ground Water Remediations Technologies Analysis Center is collecting data on perchlorate treatment studies to provide a stronger scientific understanding of the effectiveness of perchlorate treatment. The draft toxicity assessment provides additional scientific insight into the potential risks posed by perchlorate and ways to reduce those risks. Sensitive populations such as pregnant women should follow the advice of their health care provider regarding the amount and type of liquids, including water to be consumed. Concerns and questions about perchlorate and the safety of tap water can be addressed by contacting local water utilities. Contact EPA's Safe Drinking Water Hotline at 1-800-426-4791 for general information on drinking water issues. Frequently Asked QuestionsWhat is Perchlorate? How Can Perchlorate Affect Human Health? What are the Preliminary Conclusions of the Draft Toxicity Assessment?
The assessment provides a hypothetical conversion of the draft RfD to a drinking water equivalent level (DWEL), assuming factors of 70 kilogram (kg) body weight and 2 liter (L) of water consumption per day. The converted draft estimate would be 1 microgram per liter (ug/L) or 1 part per billion (ppb). If the Agency were to make a determination to regulate perchlorate, the RfD along with other considerations would factor into the final value. Does perchlorate cause cancer? Does My Water Contain Perchlorate? What Is Being Done about Perchlorate? In 1998, perchlorate was placed on EPA's Contaminant Candidate List for consideration for possible regulation. In 1999, EPA required drinking water monitoring for perchlorate under the Unregulated Contaminant Monitoring Rule (UCMR). Under the UCMR, all large public water systems and a representative sample of small public water systems are required to monitor for perchlorate over the next two years to determine whether the public is exposed to perchlorate in drinking water nationwide. How is perchlorate removed from water? Many other perchlorate studies have been completed during the last several years. A May 2000 summary of 65 perchlorate treatment studies is available online at www.frtr.gov/perchlorate (click on "Treatment Technology," then look for "GWRTAC Technology Summary"). The summary report was prepared by the Ground-Water Remediation Technologies Analysis Center. Most of the projects described in the report are bench-scale and pilot-scale demonstrations of water treatment technologies, although several entries describe full-scale systems and soil treatment methods. Most of the projects employ biological treatment methods or ion (anion) exchange technology, although reverse osmosis, nanofiltration, granular activated carbon, and chemical reduction are also discussed. Results of federally-funded perchlorate treatment research managed by the American Water Works Research Foundation (AWWARF) are also becoming available (see http://www.awwarf.org/research/TopicsAndProjects/topicSnapShot.aspx?Topic=Prchlte ). What are the next steps to developing a final toxicity assessment?
As part of the review, an external peer review workshop will be held in Sacramento, CA on March 5 and 6, 2002. The peer review meeting is open to the public and an opportunity will be provided for oral public comment. The workshop is being organized and convened by ERG. In order to accommodate interested parties, please register for the workshop either by e-mail (meetings@erg.com) or by calling the ERG registration line at (781) 674-7374. The deadline for registration is February 25, 2002. Is perchlorate-contaminated water safe to drink? Can pregnant women and children drink the water? |
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