Research teams have developed a new method that enables researchers to radiolabel three forms of perfluorinated and polyfluorinated alkyl substances (PFAS) and track the fate of these chemicals when they enter the body.
This is a significant and timely advancement in identifying and tracking these PFASs, which are known to be harmful to the human body, and just last month were found to be used extensively in fast-food wrapping paper at many popular chain restaurants.
The novelty of the newly designed method is that one of the fluorine atoms on the PFAS molecule was replaced with a radioactive form of fluorine, the same radioisotope fluorine-18 that is used for medical positron emission tomography scans in hospitals around the world.
"For the first time, we have a PFAS tracer or chemical that we have tagged to see where it goes in mice," said senior author of the study published in the Journal of Environment Science and Technology. "Each of the tracers 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."
A study released in February showed that, of the more than 400 samples of packaging materials tested from many popular fast-food restaurants, PFASs were found in 56 percent of dessert and bread wrappers, 38 percent of sandwich and burger wrappers, and 20 percent of paperboard.
Exposure to PFASs is linked to kidney and testicular cancer, elevated cholesterol, decreased fertility, and thyroid problems in adults.
Exposure to PFASs is linked to adverse effects on growth, learning and behavior and decreased immune response to vaccines in children.
A new radio tracing method developed by UAB Radiology enabled researchers to discover that highly fluorinated, potentially toxic chemicals known as perfluorinated alkyl substances, or PFASs, were found in all body organs tested, including liver, stomach, leg bone, lungs, kidney, heart, skin, muscle, brain and other organs.
Because tracing PFAS compounds conventionally is difficult, UAB Radiology developed a method to tag the intact PFAS compounds with a fluorine-18 radio tracer so researchers could see where the compound was going in the body and make sensitive measurements for the first time.
PFASs are often used in stain-resistant products, firefighting materials and nonstick cookware and not meant for ingestion. Previous studies have shown PFASs can migrate, contaminating the food and, when consumed, accumulating in the body.
Now that it appears likely that any PFASs that can be synthesized and isolated could be radiolabeled and used to directly measure uptake and biodistribution kinetics in biological systems, it opens the possibility of directly measuring uptake in human subject volunteers.
"This is possible since trace amounts of the compounds are easily measurable and the radioactivity short-lived," said the study co-author. "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."
Diseases including kidney and testicular cancers, thyroid disease, low birth weight and immunotoxicity in children, and other health issues have been linked to PFASs in previous studies.
Now that researchers have for the first time identified which PFASs initially accumulate -- and in which specific organs -- and with some surprising differences, the authors say there are health implications far beyond this initial study.