The U.S. Environmental Protection Agency signed a proposed National Primary Drinking Water Regulation (NPDWR) and Maximum Contaminant Level Goal (MCLG) for perchlorate on January 2 as a result of the D.C. Circuit’s May 2023 decision in NRDC v. Regan.
The EPA is proposing a health-based Maximum Contaminant Level Goal (MCLG) of 0.02 mg/L (20 µg/L). The EPA is co-proposing enforceable Maximum Contaminant Levels (MCLs) for perchlorate of 20 µg/L, 40 µg/L, or 80 µg/L.
The EPA is accepting comments to the public docket identified by Docket ID No. EPA-HQ-OW-2024-0592 at www.regulations.gov until March 9. The Agency will also hold a public hearing from 1-4 p.m. ET on February 19, at which time the public will be invited to provide the EPA with verbal comments. Information and registration for the public hearing is available here.
Click here for information about perchlorate and the proposed National Primary Drinking Water Regulation for perchlorate.
Perchlorate is commonly used in solid rocket propellants, munitions, fireworks, and airbag initiators for vehicles, matches, and signal flares. It can occur naturally, particularly in arid regions such as the southwestern United States.
NGWA has a best suggested practice for treating perchlorate in residential well systems. In it, the BSP states “Ingestion of perchlorate affects iodine uptake by the human thyroid and thus thyroidal hormone production,” while adding “public health risk from perchlorate remains controversial.” It has also been reported that perchlorate causes cognitive and physical damage to children.