Organoids as a Tool for Assessing Drinking Water Safety and Guidelines Relevance

Opposite page: Sampling for per- and polyfluoroalkyl substances (PFAS) in a stream that wastewater discharges into. Photo courtesy of Linda Lee. Half a century ago, in response to burning rivers and other high-profile environmental disasters, the U.S. Congress passed the Clean Water Act (CWA) as a means to protect waterways from sea to shining sea. Commemorating that landmark legislation, the Journal of Environmental Quality this year has published a collection of papers celebrating the CWA. CSA News magazine is highlighting some of that work through a three-part series. In September, we looked at research (https://doi.org/10.1002/csan.20828) on how constructed wetlands can decrease nutrient runoff on tile-drained agricultural fields. In October, we examined what scientists have learned about the benefits and challenges of using biosolids to fertilize crops, rehabilitate contaminated landscapes, and boost soil health (https://doi.org/10.1002/csan.20853). This final story in the series discusses recent research on emerging contaminants—chemicals suspected of harming people and the environment. From “forever chemicals” to disinfection by-products, and from pharmaceuticals to the lithium batteries that we too often toss in the trash, these pollutants are resulting in unintended consequences that scientists are working hard to understand. Chemicals can be convenient, useful, even lifesaving. We love them when they keep food from sticking to stuff or help us apply lipstick with ease. We love them when they power our cars, computers, and cell phones. We love them when they protect us from diseases. We love them when they make our drinking water safe. But once we’re done with them—once we have thrown them in the trash, washed them down the sink, or flushed them down the loo—they can become a lot less loveable. Some benign compounds transform into harmful ones. Some toxic molecules defy degradation. One-time helpmates can even turn deadly when they end up where we never intended—in our soil, food, tap water, and air. Welcome to the ominous world of emerging contaminants, a vast group encompassing hormones, novel pesticides, nanoparticles, microplastics, disinfection by-products (DBPs), pharmaceuticals and personal care products (PPCPs), and per- and polyfluoroalkyl substances (PFAS). Although “emerging” suggests something novel, some of these pollutants have been around for decades. But building the scientific case for regulating these contaminants is a time-consuming, costly, and often controversial process. Alex Chow, a professor in the Department of Forestry and Environmental Conservation at Clemson University, believes it is high time we learned from our mistakes. In a recent article (https://doi.org/10.1002/jeq2.20405) published in the Journal of Environmental Quality (JEQ), Chow argues that society must be more proactive about preventing contamination from chemicals whose effects may not yet be understood. Over the decades, he has watched the same story unfold over and over as if stuck on repeat: A new compound with promising applications is synthesized; it is embraced by the public and hailed by scientists, perhaps even winning a Nobel Prize (as did DDT and plastics). Eventually, the compound reveals its dark side, leaving scientists and policymakers with a costly environmental and public health mess. He now sees the same story playing out with lithium. Alex Chow collects water samples at the University of California–Berkeley’s Sagehen Field Creek Station for a study on nutrients and pyrogenic dissolved organic carbon in surface water runoff. Photo courtesy of Alex Chow. “Our Society does not recognize it, does not learn from it,” says Chow, an SSSA and ASA member. He advocates taking a more proactive approach to managing the lithium widely used in batteries before it becomes the next Nobel Prize-winning environmental menace. Soil coring for transport studies of per- and polyfluoroalkyl substances (PFAS). Photo courtesy of Linda Lee. Below we introduce you to a trio of scientists who have dedicated their careers to mitigating the fallout from three classes of emerging contaminants: DBPs, PFAS, and PPCPs. Motivated by a love of the environment, they study these compounds from multiple angles—formation and transformation, fate and transport, remediation and prevention. Between the shifting regulatory landscape, the need to detect pollutants at ever more minute concentrations, and how intricately these compounds are enmeshed in our lives, the field keeps researchers on their toes. “I feel like we’re working in an ever-changing landscape,” says Purdue University researcher Linda Lee, an SSSA and ASA member who has been in the field for decades, “a rapidly changing landscape.” As a girl, fish net in tow, Heather Preisendanz would hunt for newts, salamanders, and—her favorite—frogs in the wetlands, vernal pools, and lakes of northern New Jersey. In support of her zeal for amphibians, her family even built a pond in the backyard. “I remember hatching tadpoles as a kid and just being so amazed that this creature could start as an egg, hatch into a tadpole, and then metamorphose into a frog,” recalls Preisendanz, an SSSA member. “These were creatures that I cared about protecting. And once I realized how sensitive they can be to all the pollutants in the environment, then that turned into, I guess, what it is now.” What it is now is a career devoted to keeping bad stuff out of water. As an associate professor of agricultural and biological engineering at Penn State University, Preisendanz studies emerging contaminants like PPCPs. The COVID-19 pandemic presented her team with a unique opportunity to study what happened to our wastewater while millions of people were taking drugs to treat the virus at home and in hospitals. For a study recently published in JEQ (https://doi.org/10.1002/jeq2.20398), Preisendanz and her colleagues spent a year mid-pandemic collecting samples of wastewater as it entered (influent) and then left (effluent) two treatment facilities in Pennsylvania. One is the facility that treats Penn State’s wastewater to the state’s “class B” standard before repurposing it for irrigation on a tract of university land called the Living Filter. The other is the facility that serves the surrounding area, including a hospital, which treats wastewater to the state’s “class A+” standard before using some for irrigation and discharging the rest into a nearby stream. Preisendanz’s team tested the samples for SARS-CoV-2, the virus that causes COVID-19, as well as for prescription and over-the-counter drugs used to treat the virus. They then looked for correlations between what they found in the wastewater, COVID infection and hospitalization rates, and the number of students on campus. “We started at the most basic,” Preisendanz says. “Do we see any trends with the COVID case numbers? And then: Do we see any trends with hospitalizations?” They observed some correlations they expected: For the university samples, for example, antibiotics showed up when students were on campus but not when they weren’t. However, when COVID infection rates rose in the community, they did not see a corresponding bump in over-the-counter drugs in wastewater. Rather, variations in those levels appeared to be seasonal. Similarly, when COVID hospitalizations increased, they saw in their samples no rise in the prescription drugs used to treat the disease. Treated wastewater effluent is sprayed at Penn State’s beneficial reuse site, called the “Living Filter.” This diverts the wastewater from Spring Creek and allows the soil to act as a natural filter for any chemical residuals that remain in the wastewater. Penn State’s Heather Preisendanz has studied the effluent for emerging contaminants. Photo by Heather Preisendanz. At first, this left the scientists scratching their heads. Then they drilled down to more specific data on the number of COVID patients on ventilators, who typically receive dexamethasone. That’s when the correlations began to emerge from the data. Kristin Cochran, a Ph.D. student in the lab of University of South Carolina chemist Susan Richardson, conducts a liquid-liquid extraction of drinking water to analyze disinfection by-products (DBPs). Photo courtesy of Susan Richardson. Demand for disinfectants surged during the COVID pandemic, adding to the wastewater stream more chemicals that, under the right circumstances, could transform into harmful disinfection by-products (DBPs). “You really had to look specifically for what the medicine was being used to treat, and then the numbers made sense,” Preisendanz says. More head scratching ensued when the team detected traces of remdesivir in campus wastewater: There were no hospitalized COVID patients on campus. After a bit of sleuthing, however, they learned that a lab was running experiments using the drug around the time they detected it in the wastewater. When comparing treated wastewater, the team found that the community facility, which treated the wastewater to a higher standard, did a better job at removing some pharmaceuticals than the campus facility. They also found that, in the effluent at both facilities, levels of some pharmaceuticals remained high enough to threaten aquatic organisms. To Preisendanz, the finding highlighted how important it was to filter the effluent through soil before it would eventually reach those organisms, as both facilities do, or to release it into streams that can immediately dilute it with fresh water. Unfortunately, notes Preisendanz, not all areas of the country can offer those ecosystem services. “In more arid portions of the U.S., that’s just not true,” she says. “There, effluent is a larger portion of the streamflow, and so there is less opportunity for the streams to dilute out contaminants. If what we’re seeing holds true to other wastewater treatment facilities where these chemicals are persisting and there is less dilution happening, then potentially the risk could be higher in those areas.” Preisendanz’s work had previously focused on, as she describes it, “what’s at the end of the pipe and where it goes after it is released into the environment.” But this new study also showcases the epidemiolocal applications of wastewater and what it can tell you about the health of the population that generated it. By monitoring wastewater for pathogens or pharmaceuticals, she says, treatment facilities can alert communities about potential public health issues—and help scientists get more bang for their research buck. “These are not cheap compounds to analyze for,” Preisendanz says. The data could be leveraged through collaborations with public health experts, universities, prisons, and municipalities. “It opened the window for us to think about what we are doing differently, as having connections back to human health on the upstream side, and not just the implications after the fact.” In addition to drugs and the virus itself, there’s another class of compounds COVID helped boost in wastewater: disinfectants. Demand for disinfectants surged during the pandemic, adding to the wastewater stream more chemicals that, under the right circumstances, could transform into harmful DBPs. Disinfectants such as chlorine, widely used in public water systems, react with naturally occurring organic matter, bromide, and iodide to create DBPs, some of which have been linked to cancer and other health problems. According to Susan Richardson, a leading expert in DBPs and a professor of chemistry at the University of South Carolina (USC), more than 700 variations of the compounds have been discovered in drinking water to date. Many were first identified in her own lab, including the recent discovery of an entirely new class of them. Richardson has water in her blood, she says. She grew up on St. Simons Island off the Georgia coast where she swam, crabbed, and explored the maritime forests. These days, she uses her off time to scuba dive in tidal rivers and hunt for fossils. Her discoveries include a six-inch-tall megalodon tooth: She was so excited to find it, she recalls, that she screamed into her regulator. “You’re holding a piece of an animal in your hand that was alive millions of years ago,” Richardson says. “It’s like holding history.” Her day job also involves hunting in water. But the specimens she looks for in drinking water are even harder to spot than dinosaur fossils—and a lot more dangerous. Richardson has spent more than three decades ferreting out DBPs using mass spectrometry, first at the USEPA, and more recently at her own lab at USC. Richardson is also concerned about PFAS; she has developed a new method that screens for them by measuring the total organic fluorine in a sample. But she reserves the bulk of her scientific energy for DBPs, which she believes pose the much greater threat. Like PFAS, they are found in most waters but in far higher concentrations—micrograms per liter rather than nanograms. The epidemiologic data, she argues, indicate DBPs are much more toxic to people than PFAS. “We’ve got bladder cancer, we’ve got a little bit of colorectal cancer,” Richardson says. “And then there’s some more recent studies that show miscarriage and birth defects.” Richardson worries DBPs are losing ground to PFAS in the competition for funding and public awareness. To understand this, it helps to know how the USEPA makes tough choices about which contaminants to regulate in drinking water. The process, managed through the Safe Drinking Water Act (or SDWA, which followed the CWA by two years), takes place in five-year cycles. The National Primary Drinking Water Regulations (NPDWR) currently cover dozens of contaminants, including 11 DBPs. The agency periodically updates a contaminant candidate list, the first step for considering a compound for regulation. Some candidates end up on a much shorter list of contaminants that public water systems are required to monitor. Based in part on that data, the USEPA selects a few new compounds to regulate every cycle. Dr. Tamie Veith, a research scientist with the USDA-ARS who collaborates with Penn State’s Heather Preisendanz, downloads hydrologic and water quality data from a monitoring station in Pennsylvania’s Halfmoon Creek watershed. The monitoring station records data every 15 minutes for water level, temperature, dissolved oxygen, and rainfall. Photo by Heather Preisendanz. When, at the end of 2021, the USEPA published its latest list of contaminants to monitor, all but one of the 30 pollutants–lithium–were PFAS. The agency had to pick which poisons to target with its limited resources, and it picked PFAS. Many saw the move as long overdue: Currently, the USEPA doesn’t regulate any PFAS in drinking water (although it recently issued new health advisories). While disappointed by the USEPA’s choices, Richardson continues to build her case against DBPs, like a prosecutor determined to nail a crime ring. One key challenge has been finding the worst of the bunch. “There are definite human health effects, but we still don’t exactly know which DBP’s are the culprits,” Richardson says. “That’s what’s been driving me.” Recently, Richardson narrowed in on those culprits. With a team that includes longtime collaborator Michael Plewa, now a professor emeritus of genetics at the University of Illinois Urbana-Champaign, she produced what the authors call the most comprehensive investigation of drinking water toxicity to date. They collected drinking water from across the U.S. that had been impacted by factors such as agricultural runoff, seawater, wastewater, and algal blooms. Then, using mass spectrometry, Richardson’s team tested each sample for 72 DBPs, many of which had originally been discovered by her lab. After characterizing the samples, she sent extracts to Plewa, who exposed them to mammalian cells. The team then correlated the data to see which caused the most damage. Richardson had a pretty good idea which compound would prove the worst offender: iodoacetic acid, a DBP she had discovered in 2004. She recalls the thrill of spying the pointy peak that denoted the new chemical as it jutted up from the x axis of her mass spec results like a tooth from a dino’s jaw. Penn State lab technician Bill Clees filters a wastewater effluent sample that will be analyzed for pharmaceuticals. Photo by Heather Preisendanz. “I had looked for them, hunted for them in the past, didn’t see them,” she remembers. “And all of a sudden, we’re seeing them big as you please in drinking water.” As with other DBPs, she knew it was a disinfection by-product because the chemical shows up in treated drinking water but not in the source water. After discovering its unique chemical fingerprint and confirming its makeup, she sent a batch to Plewa for toxicology tests. “Oh my God,” he reported, as Richardson recalls. “Iodoacetic acid is the most genotoxic thing I’ve ever looked at. It was like an atomic bomb going off on my cell plates.” In the recent toxicity study, team that iodoacetic with another group called were important of drinking water correlated the most with the observed toxicity of the drinking waters class is by the one of the DBP classes the USEPA does shows no the scientists In other the USEPA the a few while the DBP off the the side, Richardson a of the toxic they would be for the USEPA to with are having to turn to quality water potential DBP from or other to Richardson. Recently, she has been water from South Carolina lakes by In a published this she and her found that, when water as little as 15 of the the of DBPs some of the most than runoff to the algal Richardson Unfortunately, those now not help for many years to if all that that be to because to up the from the she says. The of with a that have been true for other scientists emerging contaminants. For Lee, a professor of environmental that through as she about her research on PFAS, toxic compounds so widely as “forever and As an she her and from one to the At the University of she followed an in chemistry with a in environmental engineering while also working in a lab before a Ph.D. in soil chemistry and contaminant Then it was off to Purdue to and study antibiotics and in In the after as an expert in emerging contaminants, she got a call from The chemical which at the time was under for its and of PFAS, to her a to study the as I see no recalls of realized that they to the environmental of PFAS and how to analyze them. It not have in the they had but they knew that they had to have data, of their own did not well for whose PFAS had to up to the chemical The has been in of millions in and to an While of at the of this the once class of chemicals they through products like is now a The compounds have made were the of a have been the target of regulatory If there was a for emerging contaminants, PFAS would be it. of some products that could be of per- and polyfluoroalkyl substances (PFAS). They are to their and in like makeup, and where their are courtesy of With her a new mass began PFAS, and never looked Over decades, she has studied the compounds in wastewater, drinking water, and at the she once called home where decades of have in the She with Purdue and health scientists to their harmful effects on and as well as and used as animal to on In one recent she and her its from to She even and has been a treatment on carbon that PFAS. Her research as as the compounds PFAS are to their and in like makeup, and where their are There are to of PFAS out says, on how you They are the of the chemical to their They but could to Alex Chow, a professor in the Department of Forestry and Environmental Conservation at Clemson and more are key to lithium he says. Photo courtesy of “It really hard for to PFAS out of their products because in their facility from or are still being used for some says. She She has the same in her own lab. of organic we we have to it for In the U.S., the USEPA has been PFAS including over the next few years to PFAS and other emerging contaminants in drinking water. The agency released new drinking water health for some PFAS, them to the levels of per for the class called and per for the class called part per is hard to It is one in the of water it takes to and are the most of PFAS and the most In the USEPA issued a to both as substances under the Although and still the U.S. in products from other have them. But they are still in this the U.S. by a as has One group of PFAS found in food and other U.S. products is not yet these compounds end up in the portion of what out of wastewater treatment can be used as while the from or But once the PFAS in those biosolids can on a of their own as and her recently The research team examined what out of biosolids over a other they observed that the of group that includes the candidates and the far what had been in the biosolids is the of other PFAS like The toxic with these “That’s we PFAS says. “It’s PFAS to The surrounding the fate and transport of PFAS in biosolids has some communities to or even its suggests taking a few back to see the we need to is out in what to apply them, and are there that we can PFAS from the says. the idea that they be or is the of what we to for to be The harmful effects of she are of than those of “We need to on up the areas contaminated by of and biosolids and not all the PFAS to be that you your says. “We’ve a lot of in to be more are and can be hard to people can on where to regulatory and there are a lot of there are on emerging contaminants. One may be But on this the scientists More funding for this and at keeping pollutants out of the to will The in PFAS funding across is up the field says. a lot and not going What it means is that be to a lot more in all areas.” Penn State’s Preisendanz, for example, has to her emerging contaminant to PFAS. She and was on Preisendanz’s Ph.D. at are on an study on PFAS in well water, the source of drinking water for of Preisendanz also a recent study the PFAS of decades of irrigation at Penn State’s Living Her team detected PFAS across its with on While levels were they drinking water levels being by the for and as well as the USEPA’s new health about the of with treated wastewater. is key to the public and says. I to see is being to with the and that have them,” she says. to get every including the to that their choices can make even at the group has a for people who to products with Purdue to to a for the side, has or is in the of PFAS in food and other are could also boost lithium says Chow, which the USEPA’s on lithium batteries as a and more are key to lithium he says, which is to of people in the U.S. have potentially harmful levels of the in their water to the U.S. think lithium is and because at he says. if we them they will get at higher and higher Then I will a In our is celebrating the Clean Water with two new In the first Dr. Alex Chow discusses how we can a proactive approach to lithium In the Dr. discusses years of biosolids research in us at or through your for to never an

SUMMARY Regulatory authorities in the field of environmental health often grapple with decision-making in the face of scientific uncertainty and rapidly emerging data. The identification of per- and polyfluoroalkyl substances (PFAS) contamination in drinking water sources in Israel, and the need for rapid decision-making on PFAS drinking water standards, is one such example. The Water Authority, which is responsible for management of the water sector in Israel, first discovered PFAS contamination in groundwater in 2019. The Ministry of Health (MOH), which is responsible for drinking water quality, began measuring PFAS compounds in 2020. As of the end of 2024, the MOH has measured nine PFAS compounds in over 375 drinking water wells, 14.7% of which have at least one detected PFAS compound. This manuscript reviews four considerations taken into account in the decision on guideline values for PFAS: toxicological threshold, consideration of current worldwide regulatory standards, practical achievability, and analytical capacity. Based on these considerations, the MOH adopted Health Canada’s 2018 maximum acceptable concentrations in drinking water for perfluorooctanoate (PFOA) and perfluorooctane sulfonic acid (PFOS) as an interim guideline value. Subsequently, the MOH decided to adopt the EU Drinking Water Directive standards on PFAS, which include 20 PFAS compounds, and which will enter into force in 2026. To date, drinking water supply has been discontinued from four wells, and another 10 drinking water wells will be discontinued or will require treatment once the stricter standard enters force. Quarterly or annual monitoring for tens of wells is required, depending on measured PFAS concentrations. In addition to ongoing monitoring of PFAS in drinking water wells, the MOH is conducting a human biomonitoring (HBM) study to measure PFAS in blood in an adult population and is involved in work developing HBM guideline values, as part of the Partnership for Chemical Risk Assessment (PARC).

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

BackgroundExposure to per- and polyfluoroalkyl substances (PFAS) has been linked with various cancers. Assessment of PFAS in drinking water and cancers can help inform biomonitoring and prevention efforts.ObjectiveTo screen for incident cancer (2016–2021) and assess associations with PFAS contamination in drinking water in the US.MethodsWe obtained county-level age-adjusted cancer incidence (2016–2021) from the Surveillance, Epidemiology, and End Results (SEER) Program. Data on PFAS levels in public drinking water systems were obtained from the Third (UCMR3; 2013–2015) and Fifth (UCMR5; 2023–2024) Unregulated Contaminant Monitoring Rule. UCMR3 measured PFOS, PFOA, PFNA, PFHxS, PFHpA, and PFBS. UCMR5 expanded measurements to include PFBA, PFHxA, PFPeA, and PFPeS. We created indicators of PFAS detection and, for UCMR5, concentrations above Maximum Contaminant Levels (MCLs). MCLs for PFOA and PFOS are 4 ng/L, and for PFNA and PFHxS are 10 ng/L. We used Poisson regression models to assess associations between PFAS detection or MCL violation and cancer incidence, adjusting for potential confounders. We estimated the number of attributable cancer cases.ResultsPFAS in drinking water was associated with increased cancer incidence in the digestive, endocrine, oral cavity/pharynx, and respiratory systems. Incidence rate ratios (IRRs) ranged from 1.02 to 1.33. The strongest association was observed between PFBS and oral cavity/pharynx cancers (IRR: 1.33 [1.04, 1.71]). Among males, PFAS was associated with cancers in the urinary, brain, leukemia, and soft tissues. Among females, PFAS was associated with cancers in the thyroid, oral cavity/pharynx, and soft tissue. PFAS in drinking water is estimated to contribute to 4626 [95% CI: 1,377, 8046] incident cancer cases per year based on UCMR3 data and 6864 [95% CI: 991, 12,804] based on UCMR5.Impact statementThe ecological study examined the associations between PFAS in drinking water measured in two waves (2013–2015 and 2023–2024) and cancer incidence between 2016 and 2021. We found that PFAS in drinking water was associated with cancers in the organ system including the oral cavity/pharynx, lung, digestive system, brain, urinary system, soft tissue, and thyroid. Some cancers have not been widely studied for their associations with PFAS. We also observed sex differences in the associations between PFAS and cancer risks. This is the first ecological study that examined PFAS exposure in drinking water and various cancer risks.

Even as states are responding to the coronavirus pandemic, their efforts to address per- and polyfluoroalkyl substances (PFAS) in the environment and in drinking water continue. As of this writing, seven states have taken specific steps in 2020 and eight states continue to follow through on ongoing initiatives. Most state activities are focused on setting drinking water standards, with California, Maine, Massachusetts, New Jersey, and Vermont all advancing primary drinking water standards. State legislative activity continues to target PFAS in drinking water as well. In Virginia, two laws were signed that mandate efforts to develop standards for PFAS, and many other states have seen similar bills introduced. While state efforts have emerged out of frustration that federal action requires time to assess the risks posed by PFAS before taking appropriate regulatory steps, the array of federal activities and work products has changed. A key tenet that AWWA shares with many other stakeholders is that neither the federal government nor states should rely solely on the Safe Drinking Water Act to address PFAS. Preventing PFAS from entering the water supply starts with making sound decisions about if, and how, to use PFAS. While the public spotlight has often focused on PFAS in drinking water, this is slowly changing. Since the publication of the US Environmental Protection Agency's (USEPA's) PFAS Action Plan, research programs have ramped up focus on PFAS. A major component of USEPA research is the characterization of toxicity, including an ongoing effort to conduct rapid screening toxicity research for 150 PFAS and risk assessments for seven specific PFAS. There is also ongoing work to develop analytical methods for natural waters, wastewaters, biosolids, soils, and other media, with a method suitable for monitoring wastewater now available for use. Core regulatory programs at USEPA have taken steps to address PFAS as well. USEPA's solid and hazardous waste program released interim cleanup recommendations for sites contaminated with perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) that are tied directly to the existing PFOA and PFOS health advisory levels. The agency also recently added 172 PFAS to the Toxics Release Inventory (TRI), according to the National Defense Authorization Act for Fiscal Year 2020, which will help characterize facilities releasing PFAS into the environment. USEPA also has recently promulgated a rule that imposes restrictions on the commerce of products containing certain PFAS. As these efforts have proceeded, USEPA has moved forward to address PFAS in drinking water. Not only has the USEPA Office of Water proposed to regulate PFOA and PFOS, it is expected to finalize the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) to gather occurrence data for 29 PFAS using new analytical methods by next summer. While there are considerable differences in the policy debate around PFAS, one constant is the need to make science-based decisions that provide meaningful public health protection. To that end, AWWA and many others expressed support for USEPA's positive regulatory determination for PFOA and PFOS and encouraged the agency to conduct a thorough and transparent evaluation of potential standards. Additionally, AWWA and others emphasized that the agency should not consider additional PFAS yet, given outstanding data gaps and forthcoming data collection activities that would directly address those gaps. Ongoing efforts include data collection programs such as the TRI, UCMR 5, and toxicity research. These programs are expected to facilitate evaluations for more meaningful future determinations for additional PFAS with substantially more data than what are currently available. Education and outreach by the entire water sector will continue to be critical to ensure that all state and federal authorities identify and manage PFAS use. We urge the drinking water community to continue to communicate with state and local decision makers about the need for protecting public health using sound standards. Chris Moody is the regulatory technical manager at the AWWA Government Affairs Office in Washington, D.C. He can be reached at cmoody@awwa.org.

Prevalence of per- and polyfluoroalkyl substances (PFASs) in drinking and source water from two Asian countries

The aim of this study was to assess per- and polyfluoroalkyl substances (PFASs) in the Swedish aquatic environment, identify emission sources, and compare measured concentrations with environmental quality standards (EQS) and (drinking) water guideline values. In total, 493 samples were analyzed in 2015 for 26 PFASs (∑26PFASs) in surface water, groundwater, landfill leachate, sewage treatment plant effluents and reference lakes, focusing on hot spots and drinking water sources. Highest ∑26PFAS concentrations were detected in surface water (13 000 ng L-1) and groundwater (6400 ng L-1). The dominating fraction of PFASs in surface water were perfluoroalkyl carboxylates (PFCAs; 64% of ∑26PFASs), with high contributions from C4-C8 PFCAs (94% of ∑PFCAs), indicating high mobility of shorter chain PFCAs. In inland surface water, the annual average (AA)-EQS of the EU Water Framework Directive of 0.65 ng L-1 for ∑PFOS (linear and branched isomers) was exceeded in 46% of the samples. The drinking water guideline value of 90 ng L-1 for ∑11PFASs recommended by the Swedish EPA was exceeded in 3% of the water samples from drinking water sources ( n = 169). The branched isomers had a noticeable fraction in surface- and groundwater for perfluorooctanesulfonamide, perfluorohexanesulfonate, and perfluorooctanesulfonate, highlighting the need to include branched isomers in future guidelines.

As regulations ban legacy PFASs, many emerging PFASs are being developed, leading to their release into the aquatic environment and drinking water. However, research studies on these emerging PFASs in drinking water are limited, and current standards only cover a few legacy PFASs, leaving many emerging PFASs unregulated and their toxicity unknown. Therefore, a machine learning-based suspect screening combined with target screening was employed to comprehensively identify and quantify both legacy and novel PFASs in drinking water from the Yangtze River Delta, and their potential sources of contamination were determined through pollutant profile analysis. A total of 30 PFASs were identified, including 16 legacy and 14 novel PFASs, categorized into 11 classes. Quantitative and semi-quantitative analyses revealed that the maximum concentrations of 30 PFASs ranged from <LOQ (limit of quantification) to 48.92 ng/L. Notably, PFPeA (48.92 ng/L), perfluorobutanoic acid (PFBA, 44.83 ng/L), perfluorooctanoic acid (PFOA, 37.72 ng/L), perfluorobutanesulfonic acid (PFBS, 26.77 ng/L), and bis(trifluoromethanesulfonyl)imide (HNTf2, 15.02 ng/L) exhibited higher concentrations compared to other PFASs. The pollutant profile analysis suggested that PFASs in the Yangtze River Delta's drinking water are more likely to originate from pollution in the upper and middle reaches of the Yangtze River rather than from local industrial emissions. Then, the identified PFASs were prioritized by integrating the PBT (persistence, bioaccumulation, and toxicity) properties of PFASs with environmental exposure data. In the prioritization and risk assessment process, ten high-concern PFASs had Risk Indexes (RIs) higher than those of ref-PFOA and ref-PFOS, including eight legacy PFASs and two novel PFASs. The drinking water of the Yangtze River Delta originates from the surface water of the lower Yangtze River, which accumulates pollutants from its upper and middle reaches, affecting the health of over 20 million people. Our findings indicated the presence of emerging PFASs in the region's drinking water and demonstrated conceptual models for integrating chemical information from suspect screening with toxicity prediction and risk assessment. Although the current levels of emerging PFASs are relatively low, legacy PFASs still dominate. Further research is needed to identify, monitor, and assess the health and environmental risks of emerging PFASs.

Low levels of per- and polyfluoroalkyl substances (PFAS) detected in drinking water in Norway, but elevated concentrations found near known sources

Studies from areas with high level per- and polyfluoroalkyl substance (PFAS) contamination have reported significant contributions of drinking water to overall exposure but few studies have focused on general populations. To examine the association between PFAS in public water system drinking water and concentrations in serum among a general population of California adults. The CARE (California Regional Exposure) biomonitoring study measured PFAS in serum of Southern and Eastern California adults between 2018 and 2020. Participant addresses were geocoded and geographically assigned to public water systems (PWS). Between 2019 and 2022, the California State Water Resources Control Board issued investigative PFAS monitoring orders to potentially impacted PWS, focusing primarily on source wells. PFAS detections above the required reporting limit (4 ng/L for PFAS included in the final analysis) were used to assess associations with serum PFAS levels. Out of 563 participants in Southern California included in the final analysis, 314 (56%) lived in a PWS service area with at least one PFAS detected in their untreated source water and/or treated drinking water. Serum perfluorohexane sulfonic acid (PFHxS) geometric mean concentrations were 31.9% (95% CI: 11.1-56.6%) higher among participants whose PWS had at least one PFHxS detection compared to those without detectable levels. For participants with post-treatment drinking water data (n = 235), serum PFAS geometric mean concentrations were higher compared to those without detections for all modeled PFAS: PFHxS 79.9% (38.3-133.9%), perfluorooctanoic acid (PFOA) 30.4% (5.5-61.2%), perfluorooctane sulfonic acid (PFOS) 31.2% (0.7-70.9%), and ∑5 PFAS 42.0% (14.5-76.1%). This study examined the association between public water system PFAS detections and serum concentrations among a general population of Southern California adults. We found that PFAS detections in public water systems were associated with higher serum PFAS concentrations. Our findings suggest PFAS contamination in drinking water may be a significant contributor to serum PFAS levels, even among communities without high level contamination from industrial manufacturing. These results support drinking water monitoring initiatives in California to understand PFAS contamination and mitigate exposure.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are emerging contaminants that have been detected in the environment, biota, and humans. Drinking water is a route of exposure for populations consuming water contaminated by PFAS discharges. This research study reports environmental measurement concentrations, mass flows, and the fate of dozens of PFASs in a river receiving effluents from two fluoropolymer manufacturing facilities. In addition to quantified levels of PFASs using LC- and GC-MS analytical methods, the total amount of unidentified PFASs and precursors was assessed using two complementary analytical methods, absorbable organic fluorine (AOF) determination and oxidative conversion of perfluoroalkyl carboxylic acid (PFCA) precursors. Several dozen samples were collected in the river (water and sediment) during four sampling campaigns. In addition, samples were collected in two well fields and from the outlet of the drinking water treatment plants after chlorination. We estimated that 4295kg PFHxA, 1487kg 6:2FTSA, 965kg PFNA, 307kg PFUnDA, and 14kg PFOA were discharged in the river by the two facilities in 2013. High concentrations (up to 176ng/g dw) of odd long-chain PFASs (PFUnDA and PFTrDA) were found in sediment samples. PFASs were detected in all 15 wells, with concentrations varying based on the location of the well in the field. Additionally, the presence of previously discharged PFASs was still measurable. Significant discrepancies between PFAS concentration profiles in the wells and in the river suggest an accumulation and transformation of PFCA precursors in the aquifer. Chlorination had no removal efficiency and no unidentified PFASs were detected in the treated water with either complementary analytical method. Although the total PFAS concentrations were high in the treated water, ranging from 86 to 169ng/L, they did not exceed the currently available guideline values.

In this community-led pilot study we sought to investigate the utility of expanded per- and polyfluoroalkyl substances (PFAS) testing for drinking water, using a targeted analysis for 70 PFAS and the Total Oxidizable Precursor (TOP) Assay which can indicate the presence of precursor PFAS. PFAS were detected in 30 out of 44 drinking water samples across 16 states; 15 samples would exceed US EPA's proposed maximum contaminant levels for six PFAS. Twenty-six unique PFAS were identified, including 12 not covered by either US EPA Methods 537.1 or 533. An ultrashort chain PFAS, PFPrA, had the highest frequency of detection, occurring in 24 of 30 samples. It was also the PFAS reported at the highest concentration in 15 of these samples. We created a data filter to model how these samples would be reported under the upcoming fifth Unregulated Contaminant Monitoring Rule (UCMR5) requirements. All of the 30 samples with PFAS quantified by the 70 PFAS test had one or more PFAS present that would not be captured if the UCMR5 reporting requirements were followed. Our analysis suggests the upcoming UCMR5 will likely underreport PFAS in drinking water, due to limited coverage and higher minimum reporting limits. Results were inconclusive on the utility of the TOP Assay for monitoring drinking water. The results from this study provide important information to community participants regarding their current PFAS drinking water exposure. In addition, these results suggest gaps that need to be addressed by regulatory and scientific communities, in particular, the need for expanded targeted analysis of PFAS, the development of a sensitive, broad spectrum PFAS test, and further investigation into ultrashort chain PFAS.

Use of per- and polyfluoroalkyl substance (PFAS)-containing aqueous film-forming foams (AFFF) at firefighting training sites (FFTS) has been linked to PFAS contamination of drinking water. This study investigated PFAS transport and distribution in an urban groundwater aquifer used for drinking water production that has been affected by PFAS-containing AFFF. Soil, sediment, surface water and drinking water were sampled. In soil (n = 12) at a FFTS with high perfluorooctane sulfonate (PFOS) content (87% of ∑PFAS), the ∑PFAS concentration (n = 26) ranged from below detection limit to 560 ng g−1 dry weight. In groundwater (n = 28), the ∑PFAS concentration near a military airbase FFTS reached 1000 ng L−1. Principal component analysis (PCA) identified the military FFTS as the main source of PFAS contamination in drinking water wellfields >10 km down-gradient. Groundwater samples taken close to the military FFTS site showed no ∑PFAS concentration change between 2013 and 2021, while a location further down-gradient showed a transitory 99.6% decrease. Correlation analysis on PFAS composition profile indicated that this decrease was likely caused by dilution from an adjacent conflating aquifer. ∑PFAS concentration reached 15 ng L−1 (PFOS 47% and PFHxS 41% of ∑PFAS) in surface river water (n = 6) and ranged between 1 ng L−1 and 8 ng L−1 (PFHxS 73% and PFBS 17% of ∑PFAS) in drinking water (n = 4). Drinking water had lower PFAS concentrations than the wellfields due to PFAS removal at the water treatment plant. This demonstrates the importance of monitoring PFAS concentrations throughout a groundwater aquifer, to better understand variations in transport from contamination sources and resulting impacts on PFAS concentrations in drinking water extraction areas.

Research concerning the adverse health effects of per- and polyfluoroalkyl substances (PFAS) continues to grow. With the recent releases of nationwide data on PFAS in drinking water and public drinking water system service boundaries, it is now possible to conduct nationwide geospatial analyses on the relationships between PFAS in drinking water and aspects of health. To examine associations between PFAS in drinking water and cancer history prevalence in the United States. We examined cancer history prevalence, at the census tract level, among adults aged ≥ 18 years diagnosed with any cancer in or prior to 2022 using the United States Population Level Analysis and Community EStimates dataset. We obtained data for PFAS in public drinking water from the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023-ongoing). We used geographic information systems to spatially join water system boundaries (n = 9,733) with census tracts applying population-weighted areal interpolation. We calculated prevalence ratios (PRs) and 95% confidence intervals (CIs) for the associations between PFAS in drinking water and prevalence of cancer history, adjusted for census tract-level sociodemographics, health conditions and behaviors, and environmental factors. This analysis included 76,606 census tracts with an average cancer history prevalence of 7.8%. We observed positive associations of cancer history prevalence with PFAS levels in drinking water for 6:2-FTS, PFBA, PFBS, PFHpA, PFHxA, PFHxS, PFNA, PFOA, PFPeA, and PFPeS (p < 0.01). For example, for 6:2-FTS, the adjusted PR comparing the highest quintile (0.0182-0.663µg/L, population-weighted) to samples below the minimum reporting level (< 0.005µg/L) was 1.04 (95% CI 1.02-1.07, p < 0.001). No associations were observed for HFPO-DA and PFOS. Models mutually adjusted for correlated PFAS showed generally similar results. Higher levels of certain PFAS in drinking water were independently associated with higher cancer history prevalence. Future research should examine the relationships between individual-level cancer outcomes and individual-level exposure to PFAS in drinking water.

Perfluoroalkyl acids (PFAAs) in the Pra and Kakum River basins and associated tap water in Ghana.