U.S. EPA Seeks Additional NAS Input on Perchlorate

The U.S. Environmental Protection Agency’s (US. EPA) preliminary decision not to set a national standard for perchlorate in drinking water is well supported by the best available science. The agency’s intent to seek additional advice from the National Academy of Sciences (NAS) should further ensure that any final determination protects public health as well as scarce public resources.

In the meantime, the agency also announced it is replacing its existing remediation goal of 24.5 parts per billion (ppb) with an interim health advisory of 15 ppb. EPA states the interim level for perchlorate in drinking water was devised to ensure that total perchlorate exposure from food and water does not exceed the agency’s reference dose of 24.5 ppb, which is based on a recommendation by the NAS. Other states looking to EPA for guidance can rely on the health advisory as an adequate benchmark for determining what regulatory policies they may need to enact. One ppb is roughly equal to a half teaspoon of water in an Olympic-sized pool.

Among the questions the EPA seeks to have reviewed by NAS are scientific studies presented subsequent to the 2005 report. In addition, the agency is asking NAS to examine the role of perchlorate relative to other compounds that can pose risks of iodide intake inhibition at very high levels, far higher than the 24.5 ppb or 15 ppb under discussion.

The Perchlorate Information Bureau is committed to ensuring the best available scientific data guides regulatory decision-making relating to perchlorate.

For more on this topic, visit www.perchlorateinformationbureau.org.