Veterans and Firefighters Have Higher Exposures to Forever Chemicals. New CMU Research Could Improve Detection.

Forever chemicals, often known as PFAS (per- and polyfluoroalkyl substances), are complex chemical compounds that are used in consumer goods and industrial processes. There are thousands of them, and they’re so prevalent that nearly everyone has some level of forever chemicals in their bodies. Firefighting foam is one of the top three sources of forever chemicals in drinking water in the U.S. Many people are exposed indirectly through contaminated drinking water, but firefighters and members of the military who work directly with these chemicals often have higher exposure than civilians. 

New research from Carnegie Mellon University’s Mellon College of Science(opens in new window) aims to understand how these harmful chemicals build up in the body. Carrie McDonough(opens in new window), associate professor in the Department of Chemistry(opens in new window), explained how this research could support more precise testing and effective care for veterans, service members and civilians alike. 

This interview has been condensed for length and clarity.

What problems with forever chemical exposure do you want to examine in your research?

There are thousands of kinds of forever chemicals.

We know that firefighters and members of the military are directly exposed to hundreds of different forever chemicals in aqueous firefighting foams. If you are on an air force base or naval base where there is any risk of fuel fires, you will probably be close to these foams and training with them to prepare for potential fires. There's also exposure when the big tanks that they keep the foam in have to be cleaned or filled. There are many different tasks that would require direct exposure. I’ve seen photos of trainees working with these foams with no personal protective equipment, with foam on their face or foam all over their bodies, because for a long time, for all they knew — and for all their superiors knew — it was like soap.

Firefighters and military workers have health problems that could be tied to PFAS exposure, but it’s difficult to find clear indicators that their health issues are definitely linked to their occupational PFAS exposure. So the question is: How do these chemicals accumulate in the body over time? And what are the telltale signs we can test for that might indicate future health issues? 

How do you figure out which chemicals accumulate in the body and what that means?

We want to start at the source and figure out which chemicals build up in different parts of the body and which chemicals are easily excreted so that we can predict what the PFAS “fingerprint” will look like in the body. That will help us understand what we should be looking for in blood tests. So we're taking samples of things that people are exposed to, like firefighting foam and contaminated drinking water, and we will conduct lab simulations that mimic the way these chemicals break down and accumulate in your body over time. 

One simulates how liver enzymes naturally transform forever chemicals, another simulation tests how PFAS interact with proteins in blood, and the third looks at how they interact with cell membranes.  

After we do this we can say, “this is what it would look like if you were exposed to a particular material and these are the signals we should go look for in your blood to see if there’s a buildup in your body.”

What are you most excited about with this study?

After I run these lab experiments, we will feed the results into an AI model that my colleague, Oles Isayev(opens in new window), is building for active learning. We will give it lab results, and then it will try to make predictions. We’ll test those predictions, and then it can actually suggest the next structures we should test to strengthen the predictive relationships that we’re trying to build. 

Once we have enough data, we could start to use these models more preventatively instead of reactively and look at new chemicals people are making and say, "Oh, that one's going to build up in the human body easily, which could have negative health outcomes. Maybe you shouldn't use it." I'm excited about that.

What are you hoping to understand about how forever chemicals affect people?

It's a three-year study, and we’d like it to lead to better clinical guidance for health care providers and patients. People are really concerned that previous exposures could lead to health problems. Many military workers and firefighters are getting recommendations to get blood tests. We want to be able to offer more precise guidance of what to test for and look for.