Water Quality: EPA to Modify Chemical Limits for Perchlorate and Chromium 6 in Drinking Water

On Wednesday, February 2, 2011, the Obama administration outlined a more aggressive approach to curbing levels of certain chemicals in drinking water, saying it will develop a legal nationwide maximum for one chemical and signaling a separate effort to set new limits for other substances.

The Environmental Protection Agency announced that they would be moving from an advisory guideline to a mandatory limit for perchlorate, a chemical often associated with rocket fuel. The EPA also will be advancing a separate effort to set new limits for 16 other chemicals in drinking water. The Agency is particularly concerned about the substance known as chromium 6, or hexavalent chromium.

More recently, laboratory tests commissioned by the nonprofit Environmental Working Group found chromium 6 in tap water from 31 of 35 U.S. cities, with the highest levels in Norman, Okla.; Honolulu; and Riverside, Calif.

The EPA move to set its first-ever perchlorate standard comes after years of bureaucratic struggle with the Defense Department. A 2010 Government Accountability Office report found that 53 Defense Department installations had perchlorate at levels above a current advised limit of 15 parts per billion.

The Defense Department has already taken action beyond initial sampling at 48 of the 53 facilities, including some steps to remediate any contamination.

A group that includes defense contractor Lockheed Martin Corp. and perchlorate maker American Pacific Corp. challenged the EPA in a press release later Wednesday, saying that so far, no research has shown an adverse effect in humans exposed to perchlorate. The group, calling itself the Perchlorate Information Bureau, also said that perchlorate hadn’t shown up in public drinking water at levels that represent a public-health risk.

The problem could be present at more Defense Department sites than currently are being monitored, if the EPA decides that an even tougher standard is warranted. The NRDC says that a level of one part per billion is appropriate, compared with the EPA’s current advisory level of 15 parts per billion. Regulators have been studying perchlorate for more than a decade. California first required public water systems to monitor for the chemical in 1999.