EPA decides to regulate drinking-water chemical linked to thyroid cancer

02/02/2011
The U.S. Environmental Protection Agency (EPA) recently announced that it has set a national standard for the allowable level of perchlorate, a chemical linked to thyroid cancer, in tap water.

The agency will likely set the safe level at one part per billion, a level recommended eight years ago by a committee convened by the EPA, the Associated Press reports.

The news source added that this recommended level was later increased to 15 parts per billion under President George W. Bush, whose administration decided not to pass any official public health standards concerning the chemical. The new regulations will supersede that decision.



Perchlorate is a volatile molecule that contributes to the combustion reaction in airbags, fireworks and solid rocket fuel, the agency said. It was formerly used to treat to treat some forms of hyperthyroidism, a condition in which the thyroid gland overproduces hormones.



Since the chemical interferes with the production of thyroid hormone, its presence in drinking water has been associated with hypothyroidism, certain thyroid cancers and glandular disorders in pregnant women and newborns.

Extended exposure to perchlorate caused thyroid cancer in laboratory rodents, according to a study conducted by the Centers for Disease Control and Prevention (CDC).

Even if thyroid cancer were not a risk, the agency says that the chemical affects the way that the thyroid takes up iodine, which can, in turn, affect nearly every system in the body.

Once the EPA has finalized the chemical's regulation under the Safe Drinking Water Act, public water systems will be largely responsible for ensuring that the level of perchlorate stays at or below the recommended level.

The agency states that perchlorate may currently be present in the drinking water of more than 16 million Americans.

In the U.S., more than 44,000 people are diagnosed with thyroid cancer every year, according to the CDC.