New PFAS Regulations: Keys to Compliance
On March 14, 2023, the U.S. Environmental Protection Agency (EPA) proposed the first enforceable drinking water limits for six PFAS tied to adverse health effects, including PFOA and PFOS individually and four additional PFAS (PFBS, PFHxS, PFNA, GenX) in a mixture. The proposed rule would require public water systems to monitor for PFAS at some of the lowest levels ever regulated in parts per trillion. It also would require water systems to notify the public of PFAS contamination and take action, if needed. The announcement set off a flurry of responses from communities, industries, and stakeholders worldwide, who are wondering how this new regulatory framework will function.
“This is a significant decrease,” says Ian Ross, our PFAS practice leader. “The regulations mark an important shift in how we address these specific PFAS, not only in how we find and record them but in how we remove them efficiently.”
The regulations mark an important shift in how we address these specific PFAS, not only in how we find and record them but in how we remove them efficiently.
Monitor, Notify and Reduce
“There will likely be a lot of public concern over the numbers coming out of this proposed rule,” says CDM Smith PFAS and toxicology expert Heather Lanza. Lanza believes that community engagement and talking with stakeholders is critical to help allay public concerns and address the complexities around understanding, monitoring, and treating PFAS.
The proposal, if finalized, specifically targets PFOA and PFOS as individual contaminants and will regulate four other PFAS—PFNA, PFHxS, PFBS, and GenX Chemicals—as a mixture. This is the first instance of a US based drinking water regulation employing a hazard index (HI) approach; the HI is designed to account for exposures occurring to multiple PFAS at once.
Numerical levels for compliance
4.0 ng/L or ppt MCL PFOA
4.0 ng/L or ppt MCL PFOS
1.0 (unitless NOT 1ppt) Hazard Index (HI) for a mixture of PFNA, PFHxS, PFBS, and GenX
To arrive at the hazard index for the separately categorized PFAS quartet (PFNA, PFHxS, PFBS and GenX) EPA relied on toxicity data to determine the unique denominators for each compound.
“Some studies have shown that rainfall in parts of the U.S. has exceeded these levels,” says Ross. “There needs to be some consideration that we already have a widespread distribution of PFOA/PFOS at these levels, and that may impact what sites need to be cleaned up because it is also refreshing from rainfall.”
No exemptions have been provided thus far, but EPA has proposed reduced monitoring opportunities for water systems that report consecutive samples at compliant levels.
Even if the drafted regulations become final, PFAS remain a moving target. For instance, more compounds could be added to the list as toxicity assessments for PFBA, PFHxA, and PFDA are underway by EPA. And technologies for sampling, removing and destroying PFAS are constantly evolving. Currently, the list of Best Available Technologies from EPA for removing PFAS from water includes granular activated carbon (GAC), anion-exchange resin (AIX) and high-pressure membranes (Nanofiltration/Reverse Osmosis).
Via its Strategic Roadmap, EPA has also been pursuing a categorization approach. Informed by structure, mechanistic and toxicokinetic information, this would allow EPA to employ predictive mathematical techniques to estimate the physiochemical properties of PFAS in cases where data are unavailable.
Under the HI approach, additional PFAS can be added over time once more information on health effects, analytics, exposure and/or treatment becomes available.
Best Available Technologies (BATs)
Effective technologies do exist to remove PFAS in water to below the proposed limits, but the identified BATs have challenges. All of the BATs rely on separating PFAS from the water stream and transferring it to media or into concentrates, which then must be managed or disposed. None of these treatments destroy PFAS, resulting in risk that they can be re-released into the environment.
In addition, disposal of spent media is becoming increasingly difficult as traditional options (e.g., landfilling) is becoming more restrictive for PFAS-impacted waste. Ongoing work is being done to develop approaches that can cost-effectively remove and destroy PFAS, providing a permanent solution. In addition, the performance of sorption BATs (GAC, AIX) is highly dependent on the site-specific water chemistry with foulants (e.g., carbon, metals) and the low PFAS regulatory limits significantly affecting media usage rates. Site-specific bench and pilot studies are needed to select the most appropriate approach and design cost-effective systems to meet treatment objectives.
Once the draft rule is posted on the Federal Register, stakeholders have 60 days to submit comments to EPA. EPA will hold a public hearing on May 4, 2023 where the public, including water systems, can provide verbal comments on the proposed rule. The rule is targeted to be finalized in early 2024.
These efforts take time, and the proposed rule would require compliance (i.e., systems would need to be evaluated, designed, built, and operational) within three years of the rule becoming final. Therefore, the clock is ticking for many water providers who currently exceed the proposed limits.
For immediate and comprehensive compliance support, the CDM Smith team of PFAS experts is available and ready to help.