The presence of per- and polyfluoroalkyl substances (PFAS) in U.S. drinking water has emerged as a critical environmental and public health issue. Despite increasing media coverage and governmental attention, a significant gap exists in the general public’s understanding of PFAS. An exploratory study by Texas A&M AgriLife scientists and published in PLoS ONE, aimed to bridge this gap by assessing public awareness regarding PFAS and their potential impact on community health and drinking water.
Key Findings of the Nationwide Survey
Limited Public Awareness: Alarmingly, nearly half of the respondents (45.1%) were unfamiliar with PFAS. Additionally, 31.6% had heard of PFAS but lacked an understanding of what it entails.
Perception of Drinking Water Safety: A striking 97.4% did not believe their drinking water was affected by PFAS, indicating a disconnect between public perception and environmental realities.
Community Exposure as a Predictor: Awareness due to known community exposure emerged as the strongest predictor of PFAS awareness. Those aware of community exposure were more informed about PFAS sources and likely to change their product usage habits.
PFAS: An Overview
PFAS, often termed “forever chemicals” due to their persistence in the environment and in our bodies, are resistant to water, grease, and heat and found in a range of everyday products including food packaging, clothing, cosmetics, and toilet paper. PFAS have been widely used in various industrial processes and consumer products since the 1940s. Their presence in products ranging from non-stick cookware to fire extinguishing foams raises significant environmental concerns, particularly in water sources. The resistance of PFAS to degradation leads to bioaccumulation, posing serious health risks such as cancer, hormone disruption, liver damage, weakened immune systems, and reproductive harm.
Regulatory Response and Public Health Implications
The importance of knowing about PFAS lies in the need to understand the potential health risks associated with exposure to these substances. The general public’s awareness and knowledge of PFAS have been found to be limited, with only about half of the respondents in a nationwide survey stating they were aware of PFAS as an environmental contaminant. This study underscores a critical gap in public awareness and understanding of PFAS. This lack of awareness extends to the potential contamination of their primary drinking water sources.
Community exposure was identified as the strongest predicting factor regarding the level of public knowledge and awareness of PFAS and its sources. Therefore, it is crucial to provide accurate, real-time data on PFAS exposure to empower consumers to make informed decisions and take necessary precautions. Additionally, clear labeling of PFAS products is essential to allow consumers to be aware of their exposure frequency and make adjustments in product use as desired.
The Role of Effective Communication
Government agencies, research organizations, universities, utilities, and scientific institutions must collaborate to provide clear, accessible, and actionable information about PFAS, their sources, and health implications. This effort should aim to make the information relevant and understandable to the general public, encouraging informed decision-making and behavioral changes to reduce PFAS exposure. Manufacturers should clearly label their products with the presence of PFAS. This transparency allows consumers to be aware of their exposure frequency and make adjustments in product use. Consumers may want to install point-of-use treatment devices, such as under-sink or countertop filters, in their homes to remove PFAS from drinking water. These devices often use activated carbon or reverse osmosis technology to effectively reduce PFAS levels.
The largest wildfire in New Mexico’s state history burned over 300,000 acres in the summer of 2022 and came within a mile of the town of Las Vegas. The flames ultimately spared the town of 13,000, but months later, ash and soot left by the Calf Canyon/Hermits Peak wildfire fouled drinking water there when monsoon rains blanketed the region, paradoxically slamming Las Vegas with both flooding and a municipal water shortage.
Four people drowned in flash floods, and residents were forced to erect sandbag barriers to protect their houses. Meanwhile, the inundation overwhelmed the town’s water filtration system with ash contamination, forcing mandatory restrictions to cut water consumption by about two-thirds. Swimming pools went empty, and restaurants resorted to disposable dishes and utensils to cut back on dishwashing.
In September, New Mexico spent $2 million to rapidly install a temporary pre-treatment system. It is still propping up the overstrained filtration system while the town applies for federal funds for a permanent water treatment facility that the mayor estimates could cost as much as $100–200 million.
Climate change is worsening wildfires
Around the world, more extreme wildfires have become a shocking signal that the effects of climate change are here. Wildfires are now more common and more destructive, making their damage more expensive.
Climate models have predicted this worsening trend for years and suggest it will continue as long spells of hot and dry weather become more common. In California, 12 of the 20 largest fires since 1932 occurred in the last five years. In the Mediterranean, the frequency of so-called “fire weather”—hot and dry weather that leads to large wildfires—is projected to increase by up to 30% by the end of the century.
Toxic runoff dirties drinking water
Although the dramatic violence of wildfires attracts intense media coverage, long-term impacts on water quality have gone largely unreported. The problem is alarming in the U.S. West, which has wrestled with regional water shortages for years. Researchers are finding that heavy rains in areas affected by wildfires can contaminate watersheds and overwhelm municipal drinking water systems. Municipalities must often pay astronomical costs to augment, repair, or replace entire water distribution systems. With risks growing, researchers say at-risk areas must plan ahead to act quickly and communicate clearly about water issues to fire-hit residents.
Wildfires lead to increased flooding and sediment erosion into rivers because a healthy forest is no longer there to slow stormwater runoff and increase water absorption. During storms, ash from the wildfire will be carried unchecked directly into streams, where it can easily flow to a municipal water intake and overwhelm treatment plants, leading to water shortages or even total failure of municipal water systems.
Following the Rocky and Wragg fires in California, researchers studying the affected watersheds recorded drastic increases in dissolved organic carbon, dissolved organic nitrogen and ammonium. It took over a year for these levels to return to normal.
When fires burn through developed areas, toxic runoff is created from the destruction of building materials, electronics, appliances, and vehicles. Rain transports these dangerous chemicals into groundwater, contaminating private wells and municipal systems. This can force months of boil water advisories, or even do not drink/do not boil orders, where drinking water must be brought in from other areas.
Even the water distribution system itself can become a source of contamination. Following the Tubbs Fire and the Camp Fire in California, both of which burned through developed areas, researchers found that municipal drinking water exceeded exposure limits for volatile organic compounds such as benzene. The source of this contamination may have been fire damage to plastic pipes and other synthetic components of the distribution system. With so many potential sources and causes of contamination, it is challenging for public officials to define an appropriate response. This has led to conflicting or variable recommendations in the aftermath of a fire, damaging public trust in official guidance.
Can we build fire-resilient water systems?
As wildfires worsen globally, water quality problems will affect millions of people who live in threatened watersheds. In addition to cutting planet-heating emissions, specific solutions are needed to protect public health and safety from the inevitable fires to come.
Researchers who studied the aftermath of the Tubbs and Camp Fire have called for standardized and streamlined water quality monitoring following wildfires. They recommend a “do not use” order following any wildfire that burns through developed areas. Other recommendations include updated building codes to limit the spread of contaminated water within damaged distribution systems.
Clear health and safety guidance in the aftermath of a fire is crucial. In the months following the Camp Fire, surveys of 233 households within the affected community showed 54% had some level of anxiety about water contamination, and 85% were seeking alternative water sources. The public needed clear recommendations about drinking water safety, including how to conduct at-home testing. Following a fire, clear and regular communication may be required for months or years, depending on the scope of contamination.
Municipalities may also identify standard operating procedures and fire response policies before disaster strikes. A new study examining the 2021 Marshall fire in Colorado outlined potential mitigation procedures that municipalities could implement, from emergency planning to post-fire flushing protocols.
“There are very simple straightforward actions that municipalities can take today to prevent wide-scale water distribution system contamination,” said Andrew Whelton, a lead author of the study. For example: “isolating your water distribution center into zones so that if one part of the system is damaged it doesn’t spread to the other parts of the system.”
Having a plan in place will reduce confusion and increase trust and efficiency in the wildfire response, recent research suggests. One vital consideration is the level of water contamination that constitutes acceptable or unacceptable health risks.
“There are certain conditions that would indicate that your water is lightly contaminated and you should not use it,” Whelton said. “The Marshall Fire case study identifies those conditions, and another study identifies conditions of contamination in private wells. Your water can be chemically contaminated after a fire, and you have to do testing to determine if it is safe or not.”
Understanding these thresholds will lend clarity and speed to post-fire decision-making. And with climate change accelerating, the need for standardized practices that will educate the public about water safety and ensure access to clean water will only grow.
Alex Urquhartis the research and modeling manager at Energy Innovation Policy and Technology LLC® and Tanya Petachis the Climate Science Fellow at the Aspen Global Change Institute. Both organizations are Yale Climate Connections content-sharing partners.
*This post was updated Feb. 3, 2023, to reflect the correct spelling of Andrew Whelton’s name.
Editor’s note: This story is part of a nine-month investigation of drinking water contamination across the U.S. The series is supported by funding from the Park Foundation and Water Foundation. View related stories here.
Many people assume that the water that flows from our taps is free of harmful microorganisms. But each year thousands of Americans in rural areas, small towns and even some cities are sickened by living pathogens that can flourish in untreated or inadequately treated water from private wells and municipal systems.
An increase in heavy precipitation with climate change means the risk of drinking water contamination by bacteria, viruses and other microbes could also increase, especially in places where reliance on groundwater, proximity to agricultural operations and certain types of geology increase vulnerability.
Bacteria like E. coli, Salmonella and Campylobacter, and viruses like hepatitis, norovirus and rotavirus, are all found in drinking water contaminated with human and animal fecal waste. These can cause gastrointestinal and other ailments. For some that’s a matter of discomfort, but for children, the elderly and those with compromised immune systems, this can be dangerous, debilitating and even deadly.
“We’ve known for years that extreme [weather] events can cause risk for waterborne outbreaks — in developing countries, but also in developed countries,” says epidemiologist Elsio Wunder Jr., an expert in water sanitation at the Yale School of Public Health.
Pathogens in U.S. public drinking water systems cause upwards of 4 million digestive tract illnesses each year. A 2017 study by Florida State University assistant professor of geography Christopher Uejio and colleagues predicted an increase in such illnesses in children under age 5 in relation to climate change, noting the impact on “small rural” municipalities that distribute untreated groundwater in their systems.
Multiple studies have documented the risk of precipitation-driven drinking water contamination in Wisconsin, a state especially susceptible because of its livestock operations and geology. A 2010 report by Medical College of Wisconsin, Milwaukee, associate professor of pediatrics Patrick Drayna and colleagues found that visits to a Wisconsin pediatric hospital for gastrointestinal symptoms increased an estimated 11% four days after rainfall.
Rainwater courses through lagoons of manure or manure spread on fields as fertilizer, picking up pathogens and carrying them into groundwater as it seeps down into the soil. The porous dolomite that underlies parts of Wisconsin and surrounding states allows pathogen-laden rainwater to make its way into the aquifers that feed wells and municipal water systems. Human fecal pathogens can also make their way from septic systems into drinking water supplies as rainwater permeates.
“Groundwater was rainfall, it just takes a while to get there,” explains Mark Borchardt, a microbiologist for the U.S. Department of Agriculture (USDA), who reported in 2019 that 60% of wells in northeastern Wisconsin’s Kewaunee County were contaminated with microbes found in fecal waste. “Rainfall has chemistries that detach microorganisms. When it touches a pathogen attached to a soil particle, the pathogen can be released and move on.”
In northern climates, frozen ground makes it less likely that pathogens can get into groundwater in winter. But warmer winters expected with climate change likely mean that ground will be frozen less of the time and that precipitation will fall as rain instead of snow, increasing the chances for pathogens to move.
Meanwhile drought — also expected to increase with climate change — can increase the risk of pathogen contamination as well.
“At the most basic level, drought can leave people without easy access to water, and they have to get water from a less-safe source,” says Jeni Miller, executive director of the Global Climate and Health Alliance. “And with less water in the aquifers, [pathogens] become more concentrated,” meaning someone could get a higher dose of pathogens from drinking water from aquifer-fed wells, and the pathogens may be more likely to cause illness when ingested.
Source Matters
Private wells often pose the greatest risk of sickness from pathogen contamination, since there are typically no requirements for testing or treating wells, and it is usually up to an individual homeowner to discover or deal with contamination. More than 13 million households nationwide get their drinking water from such wells.
Well contamination has been a problem in not only the Midwest but in Appalachia and other regions as well, often in areas where residents lack the funds for testing or comprehensive maintenance. The organization Appalachian Voices in 2009 cited a USDA study, saying it found “over 50 percent of the private drinking water wells in the Appalachian area of Kentucky are contaminated with disease-carrying pathogens” because of poorly managed “straight” sewage pipes that contaminate surface water. A 2017 report by University of Tennessee registered nurse and then–doctoral student Erin Arcipowski and colleagues reported that pathogenic contamination of drinking water is a serious issue in low-income rural areas of Appalachia. The researchers noted that some residents lack funds for maintaining wells and might rely on “expensive bottled water from a remote convenience store” if they don’t have drinkable water at home. The study found E. coli or fecal coliform bacteria in 15 of 16 sites where water was used for drinking or recreation.
Municipal water systems that tap groundwater can also be at risk, since there are no federal mandates that groundwater be treated before distribution, according to Borchardt. About 95,000 such systems nationwide do not disinfect their water, and about 85,000 people in Wisconsin are served by systems that do not disinfect.
Federal law does require disinfection of drinking water drawn from surface sources, so there is seemingly less risk people will get sick from these systems. But treatment systems can malfunction when heavy rain makes the water more turbid (cloudy).
Parasite illustration.
In 1993 the city of Milwaukee suffered an outbreak of Cryptosporidium, a tiny parasite, that sickened more than 400,000 people with diarrhea and killed 69. A water treatment plant had inadequately treated turbid water that may have been contaminated with the parasite by agricultural or human waste carried into Lake Michigan by rain and snow melt. Between 2009 and 2017, contaminated drinking water caused 339 cases of Cryptosporidium nationwide, according to the U.S. Centers for Disease Control and Prevention.
Pipes can be a problem, too. If the distribution systems that deliver drinking water contain cracks, pathogen-laden rainwater or groundwater can infiltrate them. If pipes carrying sewage are nearby and are also leaking, rainwater can help move pathogens from sewage into drinking water.
“When pipes leak, they don’t just leak out, they also leak in,” Borchardt notes.
Groundwater was a suspected source of contamination by the “brain-eating” amoeba Naegleria fowleri in Louisiana in recent years, which is typically deadly if it enters the nose. If groundwater tapped for drinking water is not disinfected or if disinfection systems fail, Naegleria may be present in tap water. Naegleria-contaminated groundwater can also enter water systems when pipes break. There was also an outbreak in Texas this fall, and because Naegleria thrives in warm temperatures, it may become an increasing problem with climate change.
Reducing Risk
Governments and individuals can take a number of measures to reduce the risk of pathogens in drinking water. State or local governments can impose stricter controls on manure storage and spreading, including buffers and setbacks from residences.
“We currently have industrial-scale ranching and raising animals for meat and eggs, producing industrial-size pools of animal waste,” says Miller. “We need to reduce all those things that threaten our water supply as much as possible.”
Widespread testing can help identify contamination before people get sick. And municipalities that aren’t disinfecting their water can do so with UV light or other systems. Individuals can also install treatment systems for their own well water.
“More people are installing treatment systems in their homes, but systems are quite expensive, it could be several thousand dollars and requires regular maintenance which we people are not always very good at,” says Scott Laeser, water program director of the advocacy group Clean Wisconsin. “Ultimately we need to be focused on preventing pollution from contaminating our groundwater.”
Karen Levy, an associate professor of environmental and occupational health sciences at the University of Washington, has long studied waterborne disease. She said that while increased rains could mean more contamination risk in the U.S., it’s important people have faith in public drinking water systems, building the will to maintain and protect those systems, rather than turning to expensive and environmentally destructive bottled water.
“It’s really important to not scare people away from drinking water,” Levy said.
Meanwhile the risk of drinking water contamination is just one more reason, scientists agree, that people and governments must do all they can to curb climate change.
“All of the climate models show an increase in the frequency of extreme events, this means at both ends, more droughts and more floods,” says Jonathan Patz, director of the Global Health Institute at the University of Wisconsin-Madison. “The bottom line is it should be a multi-pronged, multi-level approach where not only do we have to anticipate heavy rainfall events that are expected with climate change, but instead of building systems for what we’re used to now, our water systems need to be much stronger.”
