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Perchlorate
Perchlorate is both a naturally occurring and man-made ion used to form a variety of salts. The primary use of perchlorate today is as an oxidizer in solid rocket fuel and other propellants and to a lesser extent, in fireworks, explosives, and air-bag inflators. Perchlorate has also been used medically to diagnose and treat hyperthyroidism
Perchlorate Why is perchlorate in drinking water a health concern?Perchlorate can interfere with iodide uptake into the thyroid gland. The thyroid is a central control point for a variety of hormonal responses including iodine levels. In adults, the thyroid helps to regulate metabolism. In pregnant women, severe iodide deficiency can result in major neurodevelopmental deficits and goiter in their offspring. Lesser degrees of iodide deficiency may also cause important neurodevelopmental deficits in infants and children. How does perchlorate get into drinking water?Perchlorate is highly soluble in water and has been detected in ground and surface water in 26 states and one territory. While it has often been detected in water supplies in close proximity to sites where solid rocket fuel is manufactured or used, there are also many locations in the United States lacking a clearly defined source. What is the water community doing about perchlorate in drinking water?The water community is committed to protecting public health. Water professionals are examining the occurrence of perchlorate in drinking water supplies and treatment techniques for its removal. The American Water Works Association's Water Industry Technical Action Fund (WITAF) sponsored a national occurrence study. Water utilities throughout the United States already employ several types of treatment techniques, such as ion exchange, that reduce perchlorate concentrations. The Water Research Foundation has published several studies on existing and developmental treatment techniques. Water professionals also are paying close attention to health effects research in this area. In 2004, USEPA issued a draft risk assessment recommending a reference dose of 1 part per billion (ppb) for the contaminant and has included perchlorate on its contaminant candidate list, a list of unregulated contaminants that warrant detailed study and may require future regulation. As part of USEPA's assessment, the National Research Council (NRC), a division of the National Academy of Sciences (NAS), recently completed a study on the health implications of perchlorate. The NAS report states that daily ingestion of up to 0.0007 milligrams per kilogram of body weight will not result in an adverse effect on the health of even the most sensitive populations. On February 18, 2005, USEPA announced it had set a reference dose of 0.0007 mg/kg for perchlorate, following the NAS recommendation. This translates to a Drinking Water Equivalent Level of 24.5 ppb. It is still unclear what this means for a final standard. Several states have initiated regulatory reviews to prepare a drinking water standard for perchlorate. California and Massachusetts have established standards for perchorate in drinking water of 6 ppb and 1 ppb, respectively, and New Jersey is considering a recommended standard of 5 ppb. In 2008, USEPA solicited public comment on a preliminary finding that a national primary drinking water regulation for perchlorate would not present "a meaningful opportunity for health risk reduction for persons served by public water systems.'' The agency also issued an interim health advisory for perchlorate and in mid-2009 sought additional comment on new data to support a final regulatory determination. What can consumers do if they are concerned about perchlorate in their drinking water? The best and most cost-effective way to ensure safe water at the tap is to keep our source waters clean. As a society, we should encourage policies that protect source water from contaminants introduced by human activity. As always, consumers who are concerned about their tap water should check their local utility's consumer confidence report and contact their utility with any questions or concerns. Additional ResourcesComments by AWWA on transparency and open government in the rulemaking process under the Safe Drinking Water Act, particularly with regard to a regulatory determination on perchlorate and a proposed six-year review of regulations. PDF file [100K] Added 10/2/2009 USEPA request for additional comment (PDF) For more information, contact AWWA Public AffairsGreg Kail, Senior Public Affairs Manager |
