Alligators living along the Cape Fear River in North Carolina had high levels of 14 different PFAS chemicals in their blood and showed clear signs of immune system dysfunction, according to a new study.
The Cape Fear region in North Carolina has struggled with elevated PFAS levels for decades due, in part, to the Chemours plant near Fayetteville which manufactured the chemicals.
The study, led by North Carolina State University researchers and published today in the Frontiers in Toxicology journal, suggests that per- and polyfluoroalkyl chemicals, commonly known as PFAS, are disrupting the immune systems of both exposed wildlife and humans.
“Alligators are a sentinel species – harbingers of dangers to human health,” said Scott Belcher, associate professor of biology at North Carolina State University and co-author of the study, in a statement.
The implications are substantial: the study comes on the heels of a new report that found PFAS contamination is likely at more than 57,000 locations across the U.S.
Immune system impacts add to a litany of potential health problems from PFAS, including kidney and testicular cancer, liver and thyroid problems, reproductive problems and increased risk of birth defects, among others.
This study isn’t the first evidence of PFAS immune system impacts: the chemicals are believed to suppress the ability of the immune system to make antibodies, which is vital in fighting COVID-19 and other infections. Exposed children have also shown decreased responses to childhood vaccines, and some studies of adults exposed to PFAS also have shown diminished responses to flu vaccines.
Infected gators
Belcher and his team tested 49 alligators along the Cape Fear River between 2018 and 2019. Then the team compared the results to 26 alligators from Lake Waccamaw, located in the nearby Lumber River basin, which is not as polluted with PFAS.
They tested for 23 different types of PFAS (there are an estimated 8,000 to 9,000 individual PFAS compounds). They reported an average of five different PFAS in the Lake Waccamaw alligators, compared to an average of 10 different PFAS in the Cape Fear River alligators — as well as unhealed and infected lesions.
“Alligators rarely suffer from infections,” Belcher said. “They do get wounds, but they normally heal quickly.”
The researchers tested for genes involved in stimulating immune responses: Cape Fear River alligators’ levels were 400 times higher than those of the less PFAS-polluted Lake Waccamaw alligators.
“The set of [genes] we analyzed are normally involved with viral infections,” Belcher said. “When we see elevated expression of [the genes] in these alligators, then, it tells us that something in these alligators’ immune responses is being disrupted.”
While they can’t specifically pinpoint the immune system changes to the PFAS exposure, Belcher said “seeing these associations between PFAS exposure and disrupted immune function in the Cape Fear River alligators supports connections between adverse human and animal health effects and PFAS exposure.”
See the full study on PFAS in Alligators at Frontiers in Toxicology.