A University of Arizona-led study found that exposure to “forever chemicals” in drinking water is threatening the health of babies, and costing the U.S. billions of dollars each year.
master/object/2025/12/15/plusbutton/six-plus_nQI0EiR.xmlResearchers identified a link between exposure to per- and polyfluoroalkyl substances – a series of man-made chemicals known as PFAS – in drinking water that significantly increases negative birth outcomes, such as infant mortality and extremely low birth weight.
The study also found that this contamination costs the U.S.at least $7.8 billion due to reproductive harms. Researchers say that this cost substantially outweighs current external estimates for cleaning up PFAS contamination.
Dr. Bo Guo is an associate professor of hydrology and atmospheric sciences at the University of Arizona. He said that PFAS, are persistent pollutants found everywhere globally, including public drinking water systems because they have been widely used in a variety of aspects of daily life, including non-stick cookware, waterproof outerwear and firefighting foam.
"They're basically a very large group of chemicals… once they're made it's very difficult for them to degrade,” Guo said.
In 2021, Guo gave a presentation on PFAS, and how they move in the environment. He said his goal was to bring economists and scientists together, since fewer economists understood the full impacts of forever chemicals at the time.
UA economics professors Derek Lemoine and Ashley Langer attended the lecture and agreed.
Lemoine said he was interested because prior health studies struggled to establish a connection between real-world exposure to forever chemicals and human health effects.
“I realized that there could be some common ground for us to work together,” Guo said.
The initial interaction sparked the realization that economic methodologies could be applied to untangle the complex relationship between forever chemicals and health effects.
#‘It affected how I view the toxicity of PFAS’: Why this study is different
For a long time, Guo said researchers struggled to find firm proof that the levels of PFAS we encounter daily actually cause major health problems.
Prior research on PFAS health impacts generally fell into two categories, each with significant limitations:
Toxicological studies, which involved exposing rats to high doses of PFAS. Result are difficult to apply to human populations or real-world exposure levels, researchers said. Correlational studies, which measure PFAS levels in the blood of pregnant mothers and correlate them with birth outcomes.
That is why Lemoine, Guo and Dr. Ashley Langer established an interdisciplinary research team to examine causality, and how contaminated drinking water could impact infant health outcomes.
The researchers identified a community in New Hampshire that had water contamination sites and obtained birth records from 2010 to 2019, to compare mothers whose drinking water flowed downhill from a contaminated site to mothers whose water flowed uphill, toward the contamination source.
The research found significant impacts on multiple adverse birth outcomes. Lemoine said he was surprised that they were able to detect rare health outcomes like infant mortality, extremely low birth weight and extremely preterm births based on the small sample size.
He said that this suggested a strong underlying signal of harm.
The results showed that mothers exposed to the contaminated flow saw their infant mortality rate jump by 191% within their first year of life. They also experienced a significant increase in preterm births and low-weight births.
master/object/2025/12/15/plusbutton/six-plus.xmlGuo was surprised by the results.
“I was not expecting this clear… causal relationship. Personally, it affected how I view the toxicity of PFAS,” Guo said.
The researchers extrapolated their findings from New Hampshire to the contiguous United States (U.S.) to calculate the annual costs imposed by PFAS contamination on each year's birth cohort.
Scaling these consequences across the entire country, the study found that PFAS contamination imposes an annual cost of roughly $7.8 billion, due to low-weight births alone.
"My wife was pregnant while we're doing the study and, you know, I'm seeing how PFAS affects babies,” Lemoine said. “So, we installed a water filter, and we maintain it regularly."
But that figure is likely a conservative calculation driven just by infant health harm, Lemoine said.
The $7.8-billion figure excludes additional costs from infant mortality, preterm births, and other potential long-run harms like reduced lifetime earnings and college completion due to early exposure.
This cost is estimated to be substantially larger than the price to remove these chemicals out of the public water supply–which the American Water Works Association estimates would cost less than $4 billion dollars.
“We have kids at home… we try to, you know, limit the exposure but I did not have this clear evidence of showing that, actually, if you get exposed to this … you could have this outcome. So, that was… a big change of mindset to me.”
Like Lemoine, Guo also adopted the same changes for his family, like implementing a water filter and minimizing exposure.
The study also found that short-term exposure matters.
Health effects were observable even in mothers who had lived at their location for only a short while. This suggests that cleanup efforts could yield relatively immediate public health benefits by reducing current exposure, Lemoine said.
"PFAS are everywhere,” Lemoine said, noting that New Hampshire was not an outlier. “But what we're finding is that the amount of exposure actually matters."
