California Proposes Stricter Target For Perchlorate Levels in Drinking Water

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LOS ANGELES--Citing a new study showing that low levels of perchlorate in drinking water can affect infants, the California Office of Environmental Health Hazard Assessment is proposing a stricter public health goal for the chemical.

The Jan. 7 proposal to drop the current 6 parts per billion public health goal for perchlorate in drinking water to 1 ppb comes in a technical document on which OEHHA is accepting public comment through Feb. 23.

Used in air bags, rocket fuel, military munitions, fireworks, and other explosives, perchlorate has leached into groundwater supplies across the United States. Perchlorate also can occur naturally in the environment.

In California, the chemical has forced the closure of more than a dozen of drinking water wells in San Bernardino County. Between April 2004 and April 2009, analysis of samples indicated that at least 297 drinking water sources in the state contained perchlorate concentrations above 4 ppb, according to California Department of Public Health records.

California Department of Public Health officials use public health goals to establish statewide drinking water standards.

Using the existing public health goal for the chemical, California enacted regulations in 2007 setting a maximum contaminant level of 6 ppb for perchlorate in drinking water (184 DEN A-8, 9/24/07).

New Data Cited

Scientific studies have shown perchlorate can interfere with the ability of the thyroid to absorb iodine, which is an essential nutrient. Continuous iodine deficiencies can disrupt the thyroid's ability to produce hormones that regulate the body's metabolism and physical growth.

In December, OEHHA scientists published a study in the Journal of Occupational and Environmental Medicine indicating that babies born in areas where tap water was contaminated with perchlorate faced a 50 percent chance of having a poorly performing thyroid.

“New research about perchlorate's potential to affect the health of California babies has led OEHHA's scientists to develop this revised public health goal for drinking water,” OEHHA Director Joan Denton said in a statement announcing the new proposed goal. “The revised goal reflects infants' enhanced susceptibility to the health effects of this chemical.”

California's congressional delegation has lobbied for a federal drinking water standard for the chemical for years.

OEHHA's proposal also cites new data on how much water infants consume per pound of body weight and considers infants' intake of perchlorate from infant formula, the agency said.

A public health is not considered the highest level of a chemical that is safe to drinking; rather, it is a boundary between a safe and dangerous level of the contaminant.

The Department of Public Health must set its drinking water standards as close to the corresponding public health goal as is economically and technically feasible, OEHHA said.

Defense Contractors Question Science

The Perchlorate Information Bureau, which is funded by defense contractors, including Aerojet Corp. and Lockheed Martin Corp., issued a written statement Jan. 10 calling OEHHA's technical document flawed.

“Regrettably, the best available and most credible science was not incorporated into the proposal,” the group said.

A 2005 National Academy of Sciences report found that perchlorate levels as high as 245 ppb in drinking water have no effect on the body, the statement said.

“California's announcement sets in motion an additional regulatory process by which the state standard for perchlorate in water could be lowered to 1 ppb. … Doing so would necessarily entail substantial costs for water purveyors and consumers and take more water supplies offline--all at a time when the state … is already facing historic, severe drought and massive reductions in water supplies,” the Perchlorate Information Bureau said.

In October, the Environmental Protection Agency forwarded a perchlorate regulatory determination to the White House Office of Management and Budget for review (190 DEN A-4, 10/4/10).

Information on submitting comments on California's proposed public health goal is available at

By Carolyn Whetzel

OEHHA's Draft Public Health Goal for Perchlorate in Drinking Water is available at

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