Study Links PFAS in Water to Higher Infant Mortality Risk

Thousands of industrial sites, airports and landfills in the United States still contaminate groundwater with persistent chemicals called PFAS. Present in a multitude of everyday products – packaging, textiles, fire-fighting foam – these synthetic compounds infiltrate into drinking water and accumulate in bodies. Their link with risks to human health is causing growing concern.

A team of researchers in economics and hydrology from the University of Arizona has just published an unprecedented study in the journal Proceedings of the National Academy of Sciences demonstrating the direct impact of PFAS on newborns. Their analysis, based on more than 11,000 births in New Hampshire, reveals significant increases in premature births, low birth weight and infant mortality linked to contaminated water. A strong signal, both in health and economic terms.

Understanding PFAS and their persistence in the environment

PFAS, or per- and polyfluoroalkyl substances, form a family of several thousand synthetic chemical compounds used since the 1950s. They are present in a wide range of products: food packaging, waterproof textiles, non-stick utensils, firefighting foams or industrial coatings. Their effectiveness comes from their resistance to water, oil and heat. But that’s also what makes them problematic.

These substances are called “eternal pollutants” because they do not degrade naturally. Released into the environment, they slowly migrate through the soil and reach groundwater, contaminating drinking water sources. PFOA and PFOS, two so-called “long-chain” PFAS, are the most documented. Although they are no longer produced in the United States, they remain ubiquitous in soils and continue to infiltrate water systems.

Bo Guo, professor of hydrological sciences at the University of Arizona, points out that “what we detect in drinking water is only a tiny part of what is still trapped in soils“. As if that wasn't enough, these compounds are also bioaccumulative. In other words, they accumulate in the human body over time, particularly in the blood and tissues.

Even at low doses, PFAS are associated with various health effects, including hormonal disruptions, immune disorders, cancers and impacts on reproduction. But until now, direct evidence on the concrete effects of exposure through drinking water in humans has lacked robustness. The recent study fills this gap.

A new scientific method to measure the effects on births

Faced with the difficulty of assessing the real health impact of PFAS in humans, the research team from the University of Arizona exploited a particular geographic configuration in the state of New Hampshire. Their approach is based on a quasi-natural experiment. They compared pregnant women whose homes were supplied by wells located upstream or downstream of contaminated sites.

In hydrogeology, groundwater flows in a direction determined by topography and local geology. Researchers identified 11,539 births between 2010 and 2019 within 5 kilometers of known pollution sources. They then classified the homes according to the relative position of their well in relation to these sources. This made it possible to isolate one factor: exposure to PFAS via drinking water, without the mothers being aware of it.

© Melina Lew

Illustration of the study setup.

The data were then cross-referenced with independent measurements of PFAS concentration in the wells. Levels were found to be systematically higher downstream from polluted sites. This rigorous methodology avoids the classic biases of observational studies, such as self-selection or socio-economic differences.

“This device allowed us to get closer to the conditions of a clinical trial, without intentionally exposing anyone to these products.“, explains co-author Ashley Langer. By reducing confounding variables, the team was able to more confidently attribute the observed differences in birth outcomes to exposure to PFAS through drinking water alone.

Serious and quantified health consequences on newborns

The results of the study are striking. Pregnant women exposed to PFAS-contaminated water downstream from polluted sites are at significantly higher risk of having unhealthy babies. The risk of giving birth to a low birth weight baby increases by 43% compared to women using uncontaminated water. While the risk of premature birth is increased by 20%.

Even more serious, the probability of death during the first year of life jumps by 191%. This represents, on a scale of 100,000 births, 611 additional infant deaths. The study also highlights an over-representation of extreme cases: +180% of births with a weight of less than 1,000 grams, and +168% of births before 28 weeks of gestation. These infants present a high life risk, as well as potential lifelong sequelae. This includes cognitive, respiratory or metabolic disorders.

© The Conversation, CC-BY-ND/Robert Baluja et al., PNAS 2025

Derek Lemoine, economist and co-author, specifies: “The most severe impacts affect the most fragile infants, for whom any environmental variation can have irreversible consequences.“. These effects represent a real threat to public health. Particularly in regions where water quality monitoring infrastructure is limited.

The study also stands out by quantifying these effects at the population level for the first time. By extrapolating data from New Hampshire to the United States, researchers estimate that several thousand infants are affected each year. With lasting medical and social consequences. PFAS thus become a silent but massive factor in perinatal vulnerability.

A considerable economic cost for American society

Beyond the health implications, researchers assessed the long-term economic consequences of exposure to PFAS during pregnancy. According to their calculations, the effects on low birth weights alone cost the United States about $7.8 billion per year. To this are added 5.6 billion linked to premature births and infant mortality. This brings the total to at least $8 billion in annual social losses.

These estimates take into account direct medical costs (hospitalization, neonatal care), impacts on the future health of children (deficiencies, chronic illnesses) and loss of productivity linked to reduced cognitive or physical abilities. Ashley Langer points out that “these figures remain conservative. They do not capture all the human, social or psychological dimensions of these losses“.

Faced with these amounts, the cost of water treatment may seem more reasonable. An analysis commissioned by the American Water Works Association estimates that meeting future federal PFAS standards would cost drinking water utilities about $3.8 billion annually. For researchers, the cost-benefit ratio clearly favors rapid action.

Derek Lemoine insists on this point. “The benefits in terms of public health, longevity and quality of life far exceed the costs of depollution“. These results provide an additional economic argument for environmental authorities, such as the EPA, to strengthen the regulation of PFAS and impose strict standards.

In the short term, experts recommend that at-risk households, particularly pregnant women, use activated carbon filters, which can eliminate long-chain PFAS. But only a systemic approach will make it possible to sustainably reduce exposure and its consequences.

Source: R. Baluja,B. Guo,W. Howden,A. Langer, & D. Lemoine, “PFAS-contaminated drinking water harms infants”. Proc. Natl. Acad. Sci. USA 122 (50) e2509801122