Perchlorate/Safe Drinking Water Act: U.S. Environmental Protection Agency Proposes Maximum Contaminant Level Goal/Maximum Contaminant Level

The United States Environmental Protection Agency (“EPA”) proposed in a June 26th Federal Register Notice Safe Drinking Water Act (‘SDWA”) standards for perchlorate. See 84 Fed. Reg. 30524.

EPA is proposing both a health-based Maximum Contaminant Level Goal (“MCLG”) and an enforceable Maximum Contaminant Level (“MCL”) for perchlorate.

EPA describes perchlorate as a:

. . . negatively charged inorganic ion that is comprised of one chlorine atom bound to four oxygen atoms (CIO4-), which is highly stable and mobile in the aqueous environment. Perchlorate comes from both natural and manmade sources. It is formed naturally via atmospheric processes and can be found within mineral deposits in certain geographical areas. It is also produced in the United States, and the most common compounds include ammonium perchlorate and potassium perchlorate used primarily as oxidizers in solid fuels to power rockets, missiles, and fireworks. For the general population, most perchlorate exposure is through the ingestion of contaminated food or drinking water.

Section 1412(b)(1)(a) of the SDWA addresses EPA’s authority to establish National Primary Drinking Water Regulations for contaminants. The agency states that it has determined perchlorate met the statute’s three criteria for regulating a contaminant, which include:

1. may have an adverse effect on the health of persons,
2. contaminant is known to occur or there is substantial likelihood that the contaminant will occur in public water systems with a frequency and at levels of public health concern, and
3. in the sole judgment of the Administrator, regulation of such contaminant presents a meaningful opportunity for health-risk reduction for persons served by public water systems.

EPA proposes an MCLG of 56 μg/L and an enforceable MCL of 56 μg/L.

A copy of the Federal Register Notice can be found here.