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Comments Due May 30 on PFAS National Primary Drinking Water Standard

By Vanessa Gonzales posted 05-22-2023 04:00 PM

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Comments from affected special districts and others in the public related to a proposed national drinking water standard for PFAS chemicals are due on or before May 30, 2023. The United States Environmental Protection Agency (EPA) recently held a virtual public hearing to review the proposed rule and hear public comment. This proposed standard will impact six PFAS chemicals: PFOA, PFOS, PFHxS, HFPO-DA (aka "GenX Chemicals"), PFNA and PFBS.

During the staff presentation at its public hearing, EPA reviewed the proposed standards for the six PFAS chemicals, which they divided into two categories: the first includes only two chemicals, PFOA and PFOS, which are separated from the others due to their likely carcinogenic (cancer-causing) qualities. EPA has determined that there is no safe level of human exposure for these two specific chemicals; therefore, the Maximum Contaminant Level Goal (MCLG) is zero. (An MCLG is a non-enforceable goal while an MCL (Maximum Contaminant Level) is a legally enforceable standard). However, due to the infeasibility of detecting and treating a “zero” maximum level, EPA proposes to set the legally enforceable MCL at 4.0 parts per trillion (ppt), which, according to EPA, is the lowest level of the contaminant that is both detectable and treatable.

A different standard-setting methodology, known as a “hazard index”, will be utilized for the additional four PFAS chemicals -- PFHxS, HFPO-DA (aka "GenX Chemicals"), PFNA, and PFBS. A hazard index is a common approach EPA uses that evaluates the health risk to humans from exposures to combinations of contaminants. It considers the summative toxicity of the chemicals, since they are known to coexist as mixtures and are considered more dangerous in this form. This analysis eliminates the risk that the toxicity of the chemicals will be underestimated due to a single-chemical evaluation. Public water systems will be tasked with determining the hazard index for these chemicals using a formula involving both the measured concentrations of the chemicals as well as their “safe” levels for human exposure.

Impacts on public water systems are anticipated to be significant. Systems would be required to monitor and reduce PFAS levels as well as to notify the public, either through the annual consumer confidence report (CCR) or a separate reporting mechanism. EPA estimates that 66,000 systems will be subject to the rule, with between roughly 3,400 – 6,300 expected to exceed one or more of the MCLs.

Cost estimates of compliance with the proposed rule range from $772 million to $1.2 billion annually. Disposal of treated PFAS, if required, would add an additional $30 - $61 million annually. EPA noted that there are billions of federal dollars available for PFAS remediation through various programs, including State Revolving Funds, the federal Infrastructure Act (IIJA), and more. The IIJA alone includes $9 billion in PFAS remediation funds for drinking water systems.

The rule is expected to be finalized by the end of 2023. Once promulgated, water suppliers and wastewater agencies will have three years to achieve compliance during which time regular monitoring and reporting to EPA will be required.

Once again, comments on the proposed rule are due by May 30 and must be submitted electronically at​ with the following Docket ID No.: EPA-HQ-OW-2022-0114. Materials from the webinar are available here.

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