Polyfluoroalkyl substances, known as “forever chemicals,” are present in the blood of almost everyone in the United States. The chemicals’ carbon-fluorine bonds make them resistant to natural processes, which causes PFAS to accumulate in the environment — and in the human body, according to Professor of Epidemiology Tongzhang Zheng.
In a Brown-affiliated study published last month, researchers used umbilical cord blood to provide a more comprehensive picture of PFAS exposure during fetal development, employing a new method of measuring PFAS burden.
Studying PFAS during fetal development is important because it is a “critical window of vulnerability of exposure,” wrote Zheng.
In an email to The Herald, Joseph Braun — a co-author, a professor of epidemiology and the director of the Center for Climate, Environment and Health — wrote that PFAS constitute a broad class of compounds that can be found in industrial processes, textiles and other consumer products.
“(PFAS) have contaminated our food and water,” he wrote, adding that they are able to persist in the environment for a long time.
The paper challenges some findings from earlier PFAS studies, Katherine Manz, the paper’s senior author and an adjunct assistant professor of engineering at Brown, wrote in an email to The Herald. For example, using their new measurement of PFAS burden, the researchers found that babies born to first-time mothers were found to have similar levels of exposure as babies whose mothers had been pregnant before.
The study describes a wide range of PFAS — “many of which aren’t well measured,” Manz wrote — that infants are exposed to. According to Manz, “one of the most surprising” findings was that the babies born in the early 2000s display increased exposure to many different types of PFAS at higher amounts than previously thought, Manz said.
“There are over 15,000 possible PFAS, many of which aren’t well measured,” Manz wrote. According to Manz, the researchers profiled PFAS in cord blood that could not be quantified. Because understudied chemicals are harder to quantify and thus can be missed in other analyses of exposure, performing non-targeted high resolution mass spectrometry to calculate a “burden score” for PFAs exposure enabled researchers to capture more insight into exposure.
Karl Kelsey, a professor of epidemiology and pathology and laboratory medicine who was not involved with the study, wrote in an email to The Herald that being able to accurately estimate the exposure of PFAS is “crucial” because “otherwise we cannot assess the true toxicity of” the compounds.
The most important step for scientists and policymakers to work together to reduce PFAS exposure is providing “concrete scientific evidence for policymakers and public health officials to make their decisions that are still lacking,” Zheng wrote.
But researchers are still “at the infancy” in understanding the full scope of PFAS exposure and impacts at all stages of development, from prenatal to early adulthood, he noted.
This study was part of the Cincinatti-based Health Outcomes and Measures of Environment Study, which aims to understand how exposure to environmental chemicals affects various health outcomes.
Researchers “have been following kids, now adults, since they were in their mother’s womb” since the HOME study began over 20 years ago, wrote Braun, who is one of the project’s principal investigators.
Amrita Rajpal is a senior staff writer covering science and research.
