US moves to restrict PFAS chemicals in drinking water

Article by Kerry Hebden

IN WHAT is described as a major step forward in protecting public health, the US Environmental Protection Agency (EPA) has proposed the first-ever legally enforceable national drinking water standard for six well studied PFAS chemicals that are highly resistant to degradation, and which have been linked to various health issues. 

The proposal, if finalised, would require municipal utilities to limit perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) to no more than 4 ppt in water. This is significantly lower than the previous EPA recommendation in 2016 of 70 ppt, but up from last year’s advisory health limits by the agency of 0.02 ppt and 0.004 ppt for PFOA and PFOS respectively. The discrepancy is likely the result of industry pressure on the EPA, and an inability of current tests to reliably check chemical levels in water as low as 0.02 ppt, the Guardian reports. 

The EPA’s proposal will also regulate four other PFAS – PFNA, PFHxS, PFBS, and GenX Chemicals – a newer generation of PFAS that manufacturers claimed were safer alternatives, but according to research have been found to be nearly as toxic as their predecessors. For these compounds, water systems would use a hazard index calculation to determine if the combined levels of these PFAS in drinking water pose a potential risk and require action.  

Comprising more than 4700 chemicals, PFAS are a group of widely used chemicals that have been manufactured and used broadly since the 1940s. Primarily used to make products water- and stain-resistant, PFAS have been used in products ranging from waterproof clothing to cosmetics and food packaging to carpets, but concern over their effects on human health did not start until the early 2000s when research found PFOA and PFOS in human blood.  

Health concerns

Studies have since found associations between PFOA and/or PFOS exposure with many different health complications including liver and thyroid problems, birth defects, kidney disease, decreased immunity in children, and cancer. And once they get into the environment their persistence makes remediation a serious challenge although engineers are working to overcome the problem. 

The EPA said its approach to safeguarding drinking water is a significant milestone in preventing PFAS pollution, and if its draft proposal is fully implemented “the rule will, over time, prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.”  

The proposal, if enacted, would be one of the first new chemical standards to update the US Safe Drinking Water Act since 1996. 

Many have welcomed the move, including Clean Cape Fear co-founder Emily Donovan, who said: "No one should ever wonder if the PFAS in their tap water will one day make them sick. We all deserve access to health-protective drinking water. It's a basic human right. We applaud the Biden EPA for having the courage to do what multiple administrations could not.” 

Activist and actor Mark Ruffalo, who starred in the film Dark Waters as the US environmental attorney Robert Bilott who has spent years gathering evidence and bringing lawsuits against PFAS producers, is equally in favour of the proposal.  

“After decades of delay, President Biden’s EPA has delivered a drinking water standard for PFOA and PFOS which, when finalised, will be the toughest in the nation,” he said. 

Industry pushback

However some industry groups have criticised the EPA’s proposed maximum contaminant level (MCL) regulation, saying  it will create an impossible standard that will cost manufacturers and municipal water agencies billions of dollars in compliance costs as testing and removal facilities will need to be upgraded. Law firm McGlinchey has warned that the changes could prompt public utilities to pass on the high cost of detection to their customers. 

The American Chemistry Council was also critical of the EPA’s draft proposal for MCLs saying that while it supported drinking water standards for PFOA and PFOS based on the best available science, it had serious concerns with the underlying science the EPA used to develop its levels. Calling the EPA’s approach to MCLs “misguided” and “overly conservative”, the ACC said: “all PFAS are not the same and they should not all be regulated the same way.”  

Water treatment processes

The predominant methods of removing PFAS from water are adsorptive. This includes adsorption to activated carbon or ion-exchange resin, or to air bubbles in foam/bubble fractionation. In general, longer-chain PFAS are easier to remove using adsorption than shorter-chain PFAS (along with GenX) because their adsorption coefficients to surfaces are more favourable, says chemical engineer Paul Stevenson who engineers separation technologies.  

“Of the six proscribed PFAS species, PFBS and GenX have the least favourable adsorption coefficients and the US EPA’s drinking water standard is particularly exacting. It is hard to see that legacy technologies of activated carbon and foam fractionation will be able to achieve the standard,” Stevenson said. “However, there are new colloidal process technologies on the horizon which will enable the adsorptive removal of shorter-chain PFAS to exceptionally low concentrations.” 

In a roadmap published last year, the EPA said it had issued more than 30 scientific publications on PFAS by its researchers, and that it will continue to work with federal and local governments to address PFAS in drinking water. Between 2023 and 2025 it expects to conduct tests across the country to gather data contaminants in drinking water. 

The EPA plans on combating the PFAS problem with funds secured from President Biden’s Bipartisan Infrastructure Law. The bill, which has been set up to provide vital resources in areas including highway safety, and hazardous materials, will invest US$5bn over five years to help communities that are on the frontlines of PFAS contamination. “These funds will promote access to safe and clean water in small, rural, and disadvantaged communities while supporting local economies,” the agency said. 

The EPA’s proposed regulations are currently undergoing a 90-day public comment period. It plans to finalise the rule by January 2024. 

The EPA says most uses of PFOA and PFOS have been voluntarily phased out by US manufacturers. Last year 3M pledged to discontinue production by 2025. 

EU proposed PFAS restrictions

Discussions on a potential ban on PFAS chemicals in the EU is also underway this week via a campaign dubbed the “PFAS Movement”. Initiated by the environmental NGO ChemSec, which involves lawmakers, consumer companies and institutional investors, the movement has rallied over a hundred consumer brands worth more than €130bn to strongly support a comprehensive ban on the chemicals. 

The discussions follow the recent PFAS restriction proposal, an 1800-page dossier that seeks to limit the production and use of around 10,000 PFAS chemicals, which was submitted to the European Chemicals Agency (ECHA) by the Netherlands, Germany, Denmark, Sweden, and Norway.  

According to the five national authorities around 4.4m t of PFASs will end up in the environment over the next 30 years unless action is taken soon.

Article by Kerry Hebden

Staff reporter, The Chemical Engineer

Recent Editions

Catch up on the latest news, views and jobs from The Chemical Engineer. Below are the four latest issues. View a wider selection of the archive from within the Magazine section of this site.