High levels of PFAS discharged into the Cape Fear River from a Chemours plant in Fayetteville, North Carolina, are likely making local alligators sick with autoimmune disorders that appear similar to human diseases like lupus, a new study finds.
The peer-reviewed study, published Thursday in the Frontiers in Toxicology journal, tested blood from alligators in the Cape Fear watershed that have been exposed to Chemours pollution for decades. The alligators showed extremely high levels of PFAS compounds and markers of immune disease in their blood.
“This really highlights the damage that we’re seeing across the ecosystem from PFAS, and shows we’re just starting to scratch the surface of their impacts,” said North Carolina State University researcher and study co-author Scott Belcher. “The idea that they’re going to be around and contaminating water systems for the foreseeable future is truly shocking.”
PFAS, or per- and polyfluoroalkyl substances, are a class of about 12,000 chemicals often used to make products resist water, stain and heat. They are called “forever chemicals” because they do not naturally break down, and are linked to cancer, liver problems, thyroid issues, birth defects, kidney disease, decreased immunity and other serious health problems.
Researchers discovered in 2016 that the Cape Fear river was polluted with staggering levels of PFAS. Since then, independent and state research has found PFAS pollution stemming from the Chemours plant and other sources has thoroughly contaminated the environment across hundreds of square miles, and down the Cape Fear watershed to Wilmington, 85 miles to the south.
Residents there say long term exposure to Chemours’ pollution has sickened them, and Belcher’s team previously discovered high PFAS levels in the Cape Fear’s striped bass. He suspects the species’ dwindling numbers is related to PFAS exposure’s impact on their reproductive systems. Meanwhile, the chemicals were found at alarming levels in the region’s seabirds.
The new study compared Cape Fear alligators with a cohort from Lake Waccamaw in a neighboring watershed not subjected to direct Chemours pollution. Cape Fear alligators’ blood showed much higher PFAS levels, and had twice as many compounds, including Chemours-produced chemicals like Nafion byproduct 2 and GenX.
The expressions of interferon-alpha responsive genes in the Cape Fear River alligators were 400 times higher than those of the Lake Waccamaw alligators. Interferon alpha is a secreted immune protein involved in stimulating immune response, and the type that Belcher’s team checked for responds to viral infections.
In humans, long-term high expression of this gene set is an important indicator of autoimmune disease, especially lupus. Alligators further from the plant showed lower levels of PFAS and lower expressions of interferon alpha.
The most unusual finding was a high number of unhealed or infected lesions on the alligators’ skin, which Belcher said is “super incommon”. Alligators’ lesions usually heal quickly, and the issue suggested immune system interference.
“There’s definitely something going on – all those streams of evidence really plug into this conclusion of an autoimmune disorder that looks a lot like human lupus,” Belcher said. Alligators can’t have “lupus” because they’re reptiles, he added, but noted that they are sentinel, meaning they are “harbingers of dangers to human health”. The alligators in the Cape Fear are especially useful because they live for up to 40 years and have been exposed to Chemours’ pollution for decades.
Already, research has strongly linked exposure to some types of PFAS with chronic human autoimmune disorders, like ulcerative colitis and thyroid disease. New research has shown Nafion byproduct 2 may be as toxic as PFOS, an older generation PFAS compound that is considered among the most dangerous to human health.
“The work substantiates and extends evidence from experimental models and human epidemiology studies showing that some PFAS are immune toxicants,” Belcher said.
