Scientists discover concerning new source of 'forever chemicals' in drinking water
By Abigail Kleiman
News Article: https://www.cnn.com/2025/01/06/climate/forever-chemicals-pfas-drinking-water-drugs-wellness
Journal Article: https://www.pnas.org/doi/full/10.1073/pnas.2417156122
Background Information
PFAS, or per- and polyfluoroalkyl substances, are commonly known as 'forever chemicals'. These substances are named as such because of their ability to remain in human bodies and the environment for a long time without decomposing. PFAS have long been used in consumer products, specifically because of their resistance to oil, grease, heat, and water. Despite their usefulness in the manufacturing world, PFAS have also been linked to a variety of troubling health conditions such as infertility, cancer, and thyroid issues.
One concern is that PFAS have been found in various drinking sources throughout the United States. Research suggests that nearly half of the drinking water in the US is contaminated (though not entirely by PFAS). The Environmental Protection Agency (EPA) is actively working to address this issue, passing a 2024 regulation to significantly reduce the concentrations of six PFAS in water. Despite this, the regulated PFAS do not make up a large enough portion of contaminants in drinking water to consider the problem solved. In the study discussed below, Ruyle and his colleagues examine how high organofluorine concentrations in industrial wastewater affect drinking water supplies in the US.
Journal Article
In a 2025 PNAS peer-reviewed study, Ruyle and his fellow researchers examined organofluorine contamination, how it enters wastewater, which chemicals contribute to it, and how discharges can affect downstream drinking water sources. Before this research, no method could directly measure the magnitude of PFAS and organofluorine in water. Instead, researchers estimated these values from manufacturer-released data on their compounds. Recent wastewater measurements have focused only on perfluoroalkyl acids (PFAA) but have found organofluorine with no known source, making this a key focus for these researchers.
To better measure PFA and extractable organofluorine (EOF) levels, the researchers collected wastewater samples from eight treatment plants. To best represent water across the US, Ruyle chose publicly owned treatment works (POTWs) with similar treatment technology to those serving around 70% of the country's population. The study examined two types of water: influent (wastewater entering the treatment plant) and effluent (wastewater leaving the treatment plant). The data from these POTWs were measured empirically and then inputted into the DRINCS computer model to quantify wastewater's impact on drinking water. The DRINCS model ("De facto Reuse Incidence in our Nations Consumable Supply") is a national model for the dilution of effluent wastewater into groundwater and eventually drinking water supplies.
Ruyle and colleagues found large amounts of organofluorine in the effluent wastewater, despite it passing through the treatment center. Somewhat surprisingly, they found that four PFAS (PFBA, PFPeA, PFHxA, and PFBS) accounted for only around 1% of the organofluorine in the water. Instead, the researchers found 12 fluorinated pharmaceuticals/metabolites that accounted for around 75% of the organofluorine in the influent water and 62% in the effluent. The researchers identified the parent pharmaceuticals as commonly used medications in the United States. One implication of Ruyle's findings is that wastewater treatment does not remove extractable organofluorine well, suggesting a need to improve treatment in POTWs. Additionally, they conclude that the drinking water of millions of Americans could be affected by these 'forever chemicals', leading to further health issues. Lastly, the researchers found that current PFAS legislation is not comprehensive enough, since the 2024 EPA regulation accounts for only around 7% of organofluorine in wastewater.
News Article
Sources:
Howard, J. (2023, July 5). Nearly half of US tap water contains 'forever chemicals', government study finds. CNN. https://www.cnn.com/2023/07/05/health/pfas-nearly-half-us-tap-water-wellness/index.html
Paddison, L. (2025, January 6). Scientists discover concerning new source of 'forever chemicals' in drinking water. CNN. https://www.cnn.com/2025/01/06/climate/forever-chemicals-pfas-drinking-water-drugs-wellness
Ruyle, B. J., Pennoyer, E. H., Vojta, S., Becanova, J., Islam, M., Webster, T. F., Heiger-Bernays, W., Lohmann, R., Westerhoff, P., Schaefer, C. E., & Sunderland, E. M. (2025). High organofluorine concentrations in municipal wastewater affect downstream drinking water supplies for millions of Americans. Proceedings of the National Academy of Sciences, 122(3), e2417156122. https://doi.org/10.1073/pnas.2417156122
Hey Abigail! This is a super interesting topic, and I'm surprised I haven't heard of this study before. Would it be helpful to study different types of water treatment methods and compare which is most effective, or are they generally all the same across the board? Is 23 million a conservative measurement? Could we be looking at higher numbers if there aren't programs in place to try to decrease the amount of forever chemicals in water?
ReplyDeleteHi Gabriella! I definitely think that studying different types of water treatment would be valuable research. Even within this study, the 8 wastewater plants varied in their effectiveness, with the most effective plant removing organofluorine levels by only 24%. Just studying these 8 POTWs is a great start, but I think future research will certainly explore beyond these plants and differing methods, if it hasn't already. Regarding your question about the 23 million measurement, I agree that this number could be a conservative measurement. This number was developed by the computer model DRINCS, so the actual number could be higher when not focusing on only 8 plants. On the other hand, the number could also be lower in reality depending on what treatment methods are used downstream. Thank you for your questions!
DeleteHey Abigail! PFAs are a hot topic in the media now, especially on social media. I found it interesting how you discussed PFA contaminants in our water sources. Could you explain more about the origin of these contaminants? I would love to know more about what these researchers believe is contributing to the levels of PFAs and organofluorines that are found in our water systems. Additionally, did they do any testing regarding water that is taken from more natural sources? I am just wondering if people who rely on water wells or rainwater as a supply also face these challenges that the study researched?
ReplyDeleteHi Anika! These are great questions. I discussed a little bit in my background section about how PFAS are used industrially, but they actually enter the water systems through runoff, industrial discharge, consumer products, and wastewater. Also, this study interestingly found that pharmaceuticals can account for a significant percentage of organofluorine in wastewater. These chemicals can enter the water source after people take medication and excrete them. Regarding your question about natural sources, this study specifically sampled municipal wastewater treatment plants (the POTWs I discuss) and their effects on drinking water. The researchers did not directly test wells or rainwater, but I would be interested in learning more about PFAS in these sources too.
DeleteHi Abigail! This was a very interesting read and actually has some connections to the two articles I will be discussing on Thursday. You mentioned that the news article suggests tap filtration, or simply not allowing PFAs into the environment, as solutions. I was wondering how these simplified solutions compare to ideas proposed in the journal article. I know, idealistically, not allowing PFAs into the water supply is the best option. However, given that the main source of PFAs are pharmaceuticals, wouldn’t that be nearly impossible? Also, does it note whether pharmaceutical pollution comes from human excretion? I know one of the chemical trackers used in my article comes from human excretion, which would make regulation impossible at worst and very morally questionable at best! Does the journal instead focus on finding better treatment options? Or any alternatives? Great job!
ReplyDeleteHi Jaycey! Thank you for your questions, and I am excited to hear about your articles on Thursday! I agree with you that preventing PFAS from entering water sources in the first place is the most ideal solution, but that it is not practical. Like you said, pharmaceuticals are a large source of the organofluorine in water, but many of these fluorinated drugs (like Prozac for example) are needed. The article doesn't specifically discuss how the organofluorine from the drugs enter the water, but it does discuss that conventional treatment methods are not effective at removing EOF. The researchers also discuss implementing more advanced water treatment technology, but I also believe that this is a short-term solution for reducing EOF levels. I agree with your points that it is very difficult to regulate these chemicals, and I am interested to see how future research tackles these issues.
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DeleteHi Abigail, thanks for sharing. I can see how the pharmaceutical side of PFAS pollution is neglected. I suspect that pharmaceutical lobbyists would point the blame at the materials industry. DuPont has become so synonymous with "forever-chemical pollution" from the infamous C-8 problem that marketing fluorinated products becomes the clear route if that enhanced drug outperforms all the other potential products that the company developed in the past decade. Do you think a general method for taking PFAS out of tap water will be adopted by water treatment industry before any FDA policy changes on approving new drugs with PFA metabolites?
ReplyDeleteHi Alex! Thank you for your comment! I think the point you bring up is very interesting, and I can definitely see how lobbying and politics in general impact regulation on PFAS. I do think that advancements in water treatment to remove PFAS are more likely to occur before the FDA changes their policy on drugs containing PFA metabolites. However, new water treatment technology can be very expensive to implement and their effectiveness can vary, so I am not sure how quickly those will appear either. Ruyle and his researchers did find that pharmaceuticals contributed to EOF levels in drinking water, but I still think that traditional PFAS seem to pose more of a risk. More research would definitely be required before the FDA changed their regulations. But in the meantime, improving the water treatment industry is a good way to begin reducing potential exposures.
DeleteHi Abigail! Thank you for your post! I found the contribution of fluorinated pharmaceuticals super interesting because I usually associate the contamination with industrial products. Your discussion shows everyday medication use can also complicate wastewater treatment. I also agree with your criticism that the news article should distinguish modeled exposure estimates from direct measurements. One question I had is whether the pharmaceuticals contributing to organofluorine have similar persistence and health effects to the regulated PFAS. Maybe knowing more about these differences can help clarify whether measuring total organofluorine alone tells us enough about the potential risks.
ReplyDeleteHi Jasmine! Thank you for your comment! I was surprised when I first read the journal article because I also attributed much of the water contamination to industrial products, not pharmaceuticals. From my understanding, I believe that the pharmaceuticals containing fluorine have the same health effects as the PFAS in drinking water. Any difference in behavior of these compounds is determined more by their structure and breakdown. The study I talk about also mentions that more research is needed to know potential risks of organofluorine in drinking water. I agree with you that measuring organofluorine alone is not enough, and that more research is crucial to understand EOF and water contamination.
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