Read the full article by Lauren Estes
“Water treatment specialists are facing a new challenge from emerging contaminants. Perfluoralkyl and polyfluoralkyl substances (PFAS) are a group of chemicals that include perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS) and GenX. PFOA and PFOS are long-chain polymers, made up of eight different carbon atoms, while GenX is a short-chain chemical developed to replace long-chain PFAS. With thousands of variations of both long- and short-chain PFAS, the majority of research has primarily been focused on PFOA and PFOS. Now, years after long-chain PFAS have been phased out of production, towns across the nation are facing drinking water contamination along with a question: What exactly are the health implications of ingesting these chemicals?
The U.S. EPA’s lifetime health advisory for PFOA and PFOS is 70 ppt, and there is no federal standard set yet for GenX, though the state of North Carolina has set a provisional health goal of 140 ppt. Moreover, recent toxicology research released by the Agency for Toxic Substances and Disease Registry suggests exposure could be harmful at much lower levels. The study reported that the current federal PFAS advisory level is seven to 10 times higher than when health effects were first noticed in animals…
The increasing number of contaminated drinking water systems discovered, coupled with the relative lack of toxicology data, has led to a call for action. From May 22 to 23, 2018, EPA hosted the PFAS National Leadership Summit in Washington, D.C., bringing together 200 people representing 38 states, including representatives from state, federal, industrial and water treatment industries. Topics discussed ranged from furthering health investigations to setting a maximum contaminant level (MCL). Eric Yeggy, technical affairs director for the Water Quality Assn. (WQA), represented the point-of-use (POU) and point-of-entry (POE) treatment industry at the summit.
‘It was largely put together to bring the state folks—the state regulators—in contact with the federal EPA folks so they could have a discussion, which I think they were hoping would lead towards a plan to regulate the chemicals at the federal level,’ Yeggy said. ‘Mainly, what they ended up discussing was the challenges that they are facing.’
Of which, there are many. Researchers know the most about PFOA and PFOS, which were voluntarily phased out of the U.S. market in 2015. However, that leaves an estimated 3,000 to 4,000 different chemicals that fall in the PFAS class and published analytical methods for only 39 of them. This means that there is a huge group of chemicals potentially contaminating drinking water that scientists have an extremely limited knowledge of.
‘If you were to put yourself in the shoes of the EPA and grasp, ‘How am I going to regulate this class of chemicals?’ when so little is known about the class itself, and the toxicology of it and how widespread they are,’ Yeggy said. ‘It’s an overwhelming thing.’
Because the EPA lifetime health advisory of 70 ppt only applies to PFOA and PFOS, and because of the dispute surrounding the actual toxicology level of these chemicals, different states are adopting different standards. New Jersey has adopted an amendment to the Safe Drinking Water Act rule to establish an MCL for perfluorononanoic acid (PFNA) of 13 ppt, and has proposed an MCL for PFOS of 14 ppt. In Vermont, the drinking water health advisory level for five emerging contaminants, including PFOA and PFOS, is 20 ppt. While standards range across states, attendees of the PFAS National Leadership Summit agreed that the issue is not isolated.
‘The general consensus seemed to be that these things are so widespread that if we had methods to test for all 4,000 of them, or however many there are, we would probably be finding them everywhere,’ Yeggy said. ‘I think it’s going to be a long time before the [federal agencies] find a way to actually regulate that.’
Until more information is available regarding the toxicity and persistence of these chemicals, water treatment solutions will be essential to restoring drinking water for impacted communities. According to Yeggy, WQA has been investigating reverse osmosis (RO), carbon and anion exchange as treatment solutions to PFAS contamination. In a 2008 WQA study, the association found RO systems to perform well against PFAS chemicals, while carbon-based technologies worked better on long-chain perfluorinated compounds (PFCs) than short-chain…
As information regarding toxicity longevity and water treatment methods for long-chain PFAS chemicals, such as PFOA and PFOS, is becoming more available, the next generation of those chemicals that were developed to replace them, such as GenX, are becoming a rising concern. In June 2017, GenX was discovered in the Cape Fear River, the main drinking water source for residents of Wilmington, N.C., at 700 ppt. Chemours, a spinoff of parent company DuPont, has been producing Teflon at their Fayetteville Works plant, located in Bladen County, N.C., adjacent to the Cape Fear River, since the 1980s. During that time, GenX may have been a byproduct of the Teflon production and later became an active ingredient in the early 2000s. When the people of Wilmington found out that they may have been consuming this relatively unknown contaminant for nearly 40 years, the question of long-term health effects became top of mind. The GenX Exposure Study, led by a team of researchers from North Carolina State University, is seeking to answer some of these emerging questions…
Hoppin and her team have been collecting blood, urine and tap water samples from residents impacted by the contamination. The team is looking to pioneer research regarding the longevity and toxicity of GenX and other newer PFAS compounds about which little information is available. In addition, they have been testing tap water with different kinds of POU and POE solutions, which may provide information regarding viable drinking water treatment methods.
The first round of test results have been released to participants and show promising results, while raising additional questions. The water samples collected in November 2017 showed GenX levels at approximately 50 ppt, Hoppin said, compared to 700 ppt in June 2017 and the state provisional health goal of 140 ppt. The fact that the level dropped dramatically once the plant stopped discharging industrial wastewater containing GenX into the Cape Fear River is promising, yet the lingering contamination points to non-point sources of contamination, such as soil contamination or residual groundwater or surface water contamination. Additionally, there were other contaminants that the scientists were unable to classify and quantify.
‘What we did see are these really emerging contaminants, in that these are chemicals that are a result of using fluorinated chemicals making teflon and other products, that are released to the water,’ Hoppin said. ‘We could identify them but we couldn’t quantify them because we didn’t have a chemical standard.’
Not having a chemical standard means that there is no toxicology data available and no chemical standard for toxicology testing. As much data the team has been able to gather on GenX, there remains a large class of chemicals that is largely unknown.
‘I think that people are most aware about the health effects of lead. There’s like 100 years of data that has led us to know what the numbers with lead mean,’ Hoppin said. ‘We’re just not there yet. We’re just in our infancy in understanding the whole class of PFAS and their implication [on] human health.’
The Wilmington community has remained engaged with the river’s water quality issues and with Hoppin’s study. As Chemours only provides bottled water to residents served by wells near the plant with drinking water testing above 140 ppt, other residents have turned to bottled water or filtration systems. Similar to other PFAS contaminants, RO has been found to be effective at removing a wide range of emerging contaminants. However, finding the right treatment solutions has been one issue facing Wilmington residents with drinking water contamination.”