PFAS leave fingerprints in your blood – researchers are figuring out how forever chemicals transform in your body to read these clues

Virtually every living thing on Earth, from Patagonian penguins to newborn human babies , has been touched by the synthetic chemicals known as per- and polyfluoroalkyl substances, or PFAS . In fact, you would be hard pressed to find a sample of human blood , tissue or breast milk without detectable levels of at least one type of PFAS. Making matters worse, researchers are continually uncovering links between human exposure to PFAS and poor health outcomes , including a weakened immune system , a heightened risk of kidney and testicular cancer , and pregnancy complications , including preeclampsia and reduced birth weight. The levels of some PFAS considered safe in U.S. drinking water are decreasing. Despite this, The Trump administration is in the process of revoking and possibly rewriting proposed regulations for all but PFOA and PFOS, two of the most commonly used PFAS until the early 2000s. U.S. maximum contaminant level goals for PFOA and PFOS are 0 parts per trillion – meaning there are no levels the U.S. Environmental Protection Agency considers safe . Meanwhile, thousands of PFAS have not been studied and have no regulation or oversight. In many cases, there is no monitoring data on their presence in consumer products, water and food. As an expert in chemical pollution , I have studied a wide range of synthetic and natural chemicals that can have harmful health effects for humans and wildlife. A major focus of my current research is tracing PFAS from their initial source – including consumer products, contaminated food and water, and the air – to their resulting fingerprint in an organism’s blood and tissues . By following the journey of how PFAS move into the bodies of living things – including people – scientists like me are working to improve safety recommendations and usage guidelines for these chemicals. First, though, we need to understand how these complex chemical mixtures are transformed as they accumulate in the body. What are PFAS? PFAS are a large class of organic chemicals – meaning molecules that contain carbon atoms – that have fluorine atoms added to them. This fluorination allows PFAS to aggregate on surfaces in ways that are desirable for many applications. For example, PFAS are used in nonstick cookware , food packaging , cosmetics , textiles and even toilet paper , among many other commercial and industrial products. They’re also heavily used in semiconductor manufacturing and lithium-ion batteries . PFAS are commonly called forever chemicals because of their astonishing persistence – due to the strong chemical bonds between carbon and fluorine, they don’t break down easily. This durability is desirable for manufacturers, as materials made with PFAS can function for a long time without degrading. However, persistence becomes problematic when PFAS leach or evaporate out of products and into the surrounding environment. PFAS can remain in drinking water sources and in sediment for decades to centuries. If dissolved in water or released into the air, PFAS can also travel long distances from their point of origin, ending up in remote locations. For example, PFAS initially released from industrial regions can end up in the blood of white sharks in the Atlantic Ocean or in Arctic environments . PFAS fingerprints What happens when PFAS are absorbed and accumulate in the body? When someone is exposed to PFAS, it leaves a unique pattern of chemical contamination – what researchers call a PFAS fingerprint – in their blood. Studying these PFAS fingerprints enables scientists to learn about sources of PFAS exposure and how they differ among people who live in different places, have different jobs and use different products, among other factors. But to be able to use these PFAS fingerprints, researchers first need to understand how specific exposures contribute to someone’s PFAS fingerprint over time. The composition of this fingerprint is different from the mixture of chemicals someone was initially exposed to, as some PFAS accumulate in blood to a greater extent than others. Without understanding how a PFAS mixture is distorted and changed in the body, it’s very difficult to know what sources were major contributors to a person’s lifelong PFAS exposure. For example, firefighters and military service members use aqueous film-forming foams that contain hundreds of poorly studied PFAS. These are soapy, sudsy materials that form a film over fire and starve it of oxygen . They’re commonly used in emergencies, such as airplane crashes, train wrecks, vehicle fires or any other fire involving fuels. Many firefighters and first responders who have used these foams are now grappling with serious health problems, including cancer , and many have wondered whether PFAS contributed to their illness. A clearer understanding of the PFAS fingerprint that would be expected in someone’s blood after years of using these foams could help determine whether they are a unique source of the PFAS accumulating in their blood. PFAS in the body Fingerprints at the scene of a crime are often a major clue leading detectives to the perpetrator.