In 2021 EPA made final drinking water regulatory determinations for two compounds within the family of chemicals known as per- and polyfluoroalkyl substances (PFAS). PFAS are found in many products, but drinking water contamination resulting from PFAS compounds has often been associated with fire-fighting foams. The two compounds subject to EPA’s final drinking water regulatory determinations are perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). EPA is expected to issue a proposed PFAS rule in Fall 2022 and a final rule in Fall 2023 after considering public comments on the proposal. The schedule for next steps could be:
- States adopt the rule no later than fall 2025
- Initial monitoring period, perhaps one year - 2027
- Final compliance date - some time in 2028
Of course, this schedule could move more quickly or slowly depending on a wide variety of factors. EPA is also considering establishing treatment technique requirements for PFOA, PFOS and additional PFAS as well.
As you are probably aware, several states in the U.S. have already established PFAS rules that include Maximum Contaminant Levels (MCLs). In Colorado, the legal structure to establish PFAS standards for drinking water is spelled out in statute (Colorado Revised Statutes (C.R.S. 25-1.5-202). The first step in the process is for the department to establish a priority list of contaminants for which standards may be considered and submit that list to the Water Quality Control Commission (Commission). In 2019 in its annual report to the Commission, the department submitted the list below of contaminants. These compounds were listed because of their confirmed presence in drinking water supplies and sources in Colorado, and other elements of the statutory requirements were addressed in that report as well. The list below has not been modified since 2019.
- Perfluorooctanoic acid (PFOA) Chemical Abstract Service Number (CAS No.) 334-67-1.
- Perfluorooctane sulfonate (PFOS) CAS No. 1763-23-1.
- Perfluorohexane sulfonic acid (PFHxS) CAS No. 355-46-4.
- Perfluorononanoic acid (PFNA) CAS No. 375-95-1.
As entities such as EPA or states begin the process to develop drinking water rules to address PFAS, what do they think of first? What are the considerations overall? It appears that many folks believe that regulating PFAS in drinking water is as simple as selecting MCL values, such as 70 parts per trillion (ppt) for PFOS plus PFOA, if EPA’s Health Advisory value were adopted. Actually, it’s a far more involved and complex process than that. There are many variables to consider and decisions to make.
The answer to beginning this process is that it should all flow from protecting public health. We are a Culture of Health, so this should sound natural: what are the public health risks from PFAS and how do we best address those in a rule? Are they acute health risks that can occur from brief exposure, or chronic health risks that develop over many years of exposure? Most drinking water rules are developed based on this binary categorization of health risks, and they may consider vulnerable populations, such as infants and children. However, there is some concern that PFAS may not fit neatly into one of these categories. For many people, PFAS may represent a chronic health risk, but for pregnant women or nursing mothers, perhaps there is a short-term exposure risk. This determination is yet to be made for PFAS, but it could have a profound influence on the structure and requirements of a federal PFAS rule.
The reason we must start with health is that many of the fundamental questions about how a PFAS rule will fit into the Safe Drinking Water Act structure can begin to be addressed once the nature of the health risks are established and agreed upon. This series of articles will examine the factors and variables that may go into establishing a PFAS rule with MCLs. Hopefully, this will help best prepare all of us to review EPA’s draft PFAS rule when it is published and provide constructive input to them during the comment period.
Thank you as always for your dedication to providing safe drinking water for all!
➽ Ron Falco, P.E. Safe Drinking Water Program Manager
