EPA Reviews Risk to Children of Perchlorate in Drinking Water

Last October, the Bush-era EPA made a preliminary decision not to regulate perchlorate in drinking water, saying, "The agency has determined 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."

EPA Administrator Lisa Jackson today announced that the agency will review that decision with special attention to the effects of perchlorates on the health of infants and young children.

"It is critically important to protect sensitive populations, particularly infants and young children, from perchlorate in drinking water," said Jackson. "As we re-evaluate the science around perchlorate, we will seek public input before making a regulatory determination based on the best science."

The analysis presented in the notice announced today more directly evaluates children’s exposure to perchlorate. This step takes into account the fact that infants and children consume more water per body weight than do adults.

Independence Day fireworks Sugar Land, Texas, July 4, 2008. (Photo by Amyn Kassam)

The EPA announcement pleased U.S. Senator Barbara Boxer, a longstanding proponent of setting a standard for perchlorate in drinking water who chairs the Senate Committee on Environment and Public Works.

"Perchlorate, a toxic chemical contained in rocket fuel, does not belong in our drinking water, so I am very pleased to see the Obama administration taking the first steps toward protecting our families from this dangerous contaminant," said Boxer.

"The science has made clear that perchlorate can threaten the health of pregnant women and young children across the nation, and that is why I have consistently worked for strong safeguards to protect people from this toxic chemical," she said.

Perchlorates are colorless salts that have no odor and dissolve easily in water. They have been found in many foods, such as milk and lettuce, and in some drinking water supplies.

The federal Agency for Toxic Substances cites recent studies showing "widespread exposure to low levels of perchlorate by the general population."

Perchlorates enter the environment where rockets are made, tested, and taken apart. People are exposed to perchlorates before and after fireworks shows and when using road safety flares.

Exposure also occurs during use of certain cleaning products and pool chemicals. Factories that make or use perchlorates may also release them to soil and water.

The Agency for Toxic Substances says that rain will wash perchlorates out of soil and into ground water. "We do not know exactly how long perchlorates will last in water and soil, but the information available indicates that it is a very long time," the agency warns.

In January 2005, the National Research Council published a review of the state of the science regarding potential adverse health effects of perchlorate exposure.

The NRC found that perchlorates can interfere with the normal functioning of the thyroid gland by interfering with the uptake of iodine, an important component of two thyroid hormones.

In pregnant women, perchlorate exposure can result in low thyroid hormone levels, or hypothyroidism, that affect their unborn children, the NRC review concluded, warning that the children can suffer "neurodevelopmental delays and IQ deficits" despite hormone remediation.

Yet, the NRC committee concluded that the available evidence did not show a causal association between perchlorate and congenital hypothyroidism, changes in thyroid function in normal birthweight, full-term newborns, or hypothyroidism or other thyroid disorders in adults.

The committee considered the evidence to be inadequate to determine whether or not there is a causal association between perchlorate exposure and adverse neurodevelopmental outcomes in children.

The committee noted that no studies have investigated the relationship between perchlorate exposure and adverse outcomes among the offspring of mothers who had low dietary iodine intake, or low-birthweight or preterm infants.

In response to its 2008 preliminary determination not to regulate perchlorate, EPA received and reviewed comments from more than 32,000 individuals and organizations.

One of the commenters who encouraged regulation wrote "the contamination of water supplies by perchlorate is on-going" and "perchlorate that has entered the soil and contaminated aquifers will likely lead to additional impacted sites."

Another commenter wrote that "a number of states are moving to regulate perchlorate and a patchwork of different regulations will confuse the public and the regulated water community."

One commenter opposed to regulating perchlorate wrote that perchlorate "does not appear, at this stage, to be a nationwide problem."

Now, the EPA is offering a renewed opportunity for public comment on regulating perchlorate in drinking water. The current notice will be available for public comment 30 days after publication in the Federal Register.

For more perchlorate information from the EPA, click here.

Copyright Environment News Service, ENS, 2009. All rights reserved.