Scientists from the University of Alabama at Birmingham’s School of Medicine, in collaboration with the University of Notre Dame, have developed a new method to track toxic chemicals when they enter the body. They have developed a new radio tracking method to track PFAs. According to the researchers, this is a significant and timely advancement in identifying and tracking these PFAs compounds.
In this radio-tracking method, one of the fluorine atoms on the PFAS molecule was replaced with a radioactive form of fluorine. The fluorine is also used for medical positron emission tomography scans in hospitals worldwide.
PFAs are known to be toxic to the human body. Exposure to PFASs is linked to kidney and testicular cancer, elevated cholesterol, decreased fertility, and thyroid problems in adults. It also affects adverse effects on growth, learning, and behavior and decreases children’s immune response to vaccines. Finding the PFAS compound is a relatively difficult task. But this radio-tracking method discovers highly fluorinated, potentially toxic chemicals known. For example, perfluorinated alkyl substances, or PFASs.
The method tags the intact PFAS compounds with a fluorine-18 radiotracer. It enables scientists to see where the compound was going in the body. They then make sensitive measurements for the first time.
Suzanne Lapi, Ph.D., senior author of the study, said, “For the first time, we have a PFAS tracer or chemical that we have tagged to see where it goes in mice. Each of the traces exhibited some degree of uptake in all of the organs and tissues of interest that were tested, including the brain. The highest uptake was observed in the liver and stomach, and similar amounts were observed in the femur and lungs.”
“Conventionally, tracing these PFAS compounds is very difficult. These compounds are not UV active, and they’re very difficult to detect. There are some techniques where you can detect total fluorine concentration, but that does not give you an idea of which compound the fluorine is attached to. With our method, we can actually tag the intact compound with a fluorine 18 radiotracer, and it gives us a handle so we can see where that compound is going and make very sensitive measurements.”
“These sensitive measurements are probably the most important thing because it’s so difficult to detect in other methods, where you would have to take the liver out, homogenize it, extract the chemical out and do mass spectrometry to see how much of the chemical is in there. And you’d have to do it with every single organ. For us, we can take the whole mouse, image it, and we’re done. Or we can take the issues and we can count it, and we’re done. It’s a much quicker and less time-consuming method to look at where these go.”
It is the first time; scientists could time-identified PFASs initially accumulate in specific organs with some surprising differences. It appears that PFAs could be synthesized and isolated could be radiolabeled. Furthermore, it might directly measure uptake and biodistribution kinetics in biological systems.
Graham Peaslee, Ph.D., the study co-author said, “This is possible since trace amounts of the compounds are easily measurable and the radioactivity short-lived. It’s an important discovery because PFASs are a really persistent chemical that, once in the bloodstream, stays there and accumulates, which is not good.”
“There was concern that these chemicals might directly enter the food that was wrapped with treated packaging. A larger concern is that, because these chemicals persist for a long time in the environment when the treated consumer products enter the landfill, these chemicals will re-emerge into our drinking water. These overall results already call into question the safety of these alternative shorter-chain PFAS compounds.“
In addition, the method can also be used to study PFAS behavior. This could measure the fate of radiolabeled compounds in environmental treatment systems.
Lapi said, “While I don’t think we will look at all of these PFASs, we would like to look at different families of these compounds. Next, we will see how they are distributed in the body. Because even with very small changes in these compounds, we were able to see differences in brain uptake. This is important because these may have neurological impacts. We saw different clearance patterns, blood binding, and other things. We want to look at different classes of compounds. For example, how they’re excreted from the body, how they accumulate. Then we will see if we can really say something about how you would get rid of these compounds.”
Now, scientists want to know if this radio-tracking method is useful for cleanup compounds in environmental situations with a contaminate issue.
- Jennifer L. Bartels, Tolulope A. Aweda, Adam J. Rosenberg, David M. Lunderberg, Graham F. Peaslee, and Suzanne E. Lapi. Radiosynthesis and Biological Distribution of 18F-Labeled Perfluorinated Alkyl Substances Environmental Science & Technology Letters 2017 4 (6), 211-215 DOI: 10.1021/acs.estlett.7b00042