GAO Report Calls For EPA To Better Track Perchlorate Pollution

EPA should work with the states and other federal agencies to establish a formal structure to track and monitor perchlorate detections and the status of cleanup efforts in the United States and its territories, a report from the Government Accountability Office recommended.

A GAO report, made public June 21, stated that without a formal system to track and monitor perchlorate findings and cleanup activities, EPA and the states do not have the most current and complete accounting of perchlorate as an emerging contaminant of concern, including the extent of perchlorate found and the extent or effectiveness of cleanup projects. "As a result, a greater number of contaminated sites than we reported may already exist," GAO stated.

Additionally, the Defense Department is reluctant to sample for contamination near active military bases unless required by law. "Except where there is a specific legal requirement, DOD's perchlorate sampling policy requires the services to sample only under certain conditions. Cleanup is planned or under way at 51 of the almost 400 perchlorate-contaminated sites identified to date," GAO stated.

Perchlorate contamination has been found in water and soil at almost 400 sites in the United States where concentration levels ranged from a minimum reporting level of 4 parts per billion (ppb) to millions of ppb. More than one-half of all sites were in California and Texas, and sites in Arkansas, California, Texas, Nevada and Utah had some of the highest concentration levels. Yet, most sites had lower levels of contamination; roughly two-thirds of sites had concentration levels at or below the EPA's provisional cleanup standard of 18 ppb.

Public drinking water systems accounted for more than one-third of the sites where perchlorate was found. EPA sampled more than 3,700 public drinking water systems and found perchlorate in 153 systems across 26 states and two U.S. commonwealths. Perchlorate concentration levels found at public drinking water systems ranged from 4 ppb to 420 ppb. However, only 14 of the 153 public drinking water systems had concentration levels above 24.5 ppb.

Although there is no specific federal requirement to clean up perchlorate or a specific perchlorate cleanup standard, EPA and state environmental agencies have investigated, sampled and cleaned up unregulated contaminants, such as perchlorate, under various federal environmental laws and regulations. Further, under certain federal and state environmental laws, private industry may be required to sample for contaminants, such as perchlorate. According to EPA and state officials, private industry and public water suppliers have generally complied with regulations requiring sampling and agency requests to sample.

Since 1998, EPA and DOD have sponsored a number of perchlorate health risk studies using varying study methodologies. GAO reviewed 90 of these studies that generally examined whether and how perchlorate affected the thyroid. About one-quarter concluded that perchlorate had an adverse effect. In January, the National Academies' National Research Council reported on the potential health effects of perchlorate and concluded that a total exposure level from all sources, higher than that initially recommended by EPA (a dose equivalent to 1 ppb in drinking water, assuming that all exposure came from drinking water) may not adversely affect a healthy adult. On the basis of NAS' report (, EPA revised its reference dose to a level that is equivalent to 24.5 ppb in drinking water (if it is assumed that all exposure comes only from drinking water).

EPA agreed with GAO's findings and conclusions on the extent of perchlorate in the United States and also agreed that defense-related activities have been found to be associated with perchlorate detections. However, EPA did not agree with GAO's recommendation that it establish a formal structure to centrally track and monitor perchlorate detections and the status of cleanup efforts across the federal government and state agencies.

DOD, in commenting on a draft of the report, stated that GAO did not provide an accurate assessment of perchlorate issues and activities. DOD asserted that the report mischaracterized DOD's response to perchlorate and cited examples of where DOD has sampled and invested in cleanup technologies, even though perchlorate is currently unregulated. Finally, DOD disagreed with GAO's recommendation that EPA establish a more formal structure to centrally track and monitor perchlorate because it believes that it is not clear that such a system will provide added value.

DOD stated that it will continue to share its information on perchlorate. However, in its comments on this report, DOD provided information on four locations where perchlorate has been found, in one case as long as five years ago, but these locations do not appear on EPA's list of perchlorate detection sites, according to GAO. "Whether this omission occurred as a result of a DOD or an EPA oversight is unknown, but it underscores the need for a more structured and formalized system," GAO stated.

The report, Perchlorate: A System to Track Sampling and Cleanup Results Is Needed, GAO-05-462, can be accessed at

This article originally appeared in the 06/01/2005 issue of Environmental Protection.

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