Bald Head Island Alligators are Exposed to PFAS (“Forever Chemicals”)
November 12, 2022
A recent study of alligators in the Cape Fear River found the animals had elevated levels of 14 different per- and polyfluoroalkyl (PFAS) chemicals in their blood serum, as well as clinical and genetic indicators of immune system effects. The work adds to the body of evidence connecting PFAS exposure with adverse immune system effects.
A number of these Cape Fear alligators were captured on Bald Head Island in 2019. The Bald Head Island Conservancy has partnered with the study authors, Dr. Scott Belcher and Dr. Theresa Guillette and their lab from NC State University, to conduct alligator health assessments and take blood samples for environmental toxins.
Belcher is an ecotoxicologist studying health effects of PFAS (per- and polyfluoroalkyl substances) in the Cape Fear River watershed. PFAS are “forever chemicals” found in Cape Fear drinking water from an upstream industrial source – but are also found in water, air, fish, and soil at locations across the nation and the globe. Scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals.
Alligators captured on Bald Head Island had some of the highest serum concentrations of GenX in the study, and higher serum concentrations of total PFAS than a control site (Lake Waccamaw). These findings were surprising because Bald head Island’s freshwater source is predominantly groundwater and precipitation. It is unknown what the sources of PFAS on BHI might be.
Alligators can be good indicators of environmental effects on immune function because they normally have very robust immune systems and they are almost constantly exposed to fresh water. Alligators exposed to PFAS throughout the Cape Fear watershed had adverse immune effects including unhealed or infected lesions, and high expression of a set of genes that indicate immune response disruption. BHI alligators were not sampled for these factors, however.
The Conservancy’s work with the Belcher Lab continues through our satellite tagging project, in which we are tracking alligator movements and potential exposure to different water sources. Hopefully this will help reveal sources of PFAS to the BHI watershed that could be affecting wildlife and humans alike.
Figure 1. Total PFAS concentrations in alligator blood serum from Bald Head Island (BHI), Cape Fear River (CFR), Lake Waccamaw (LW). Median PFAS concentration was significantly higher in BHI and CFR alligators than LW samples (Guillette et al. 2022).
Figure 2. GenX concentrations in alligator blood serum from Bald Head Island (BHI), Cape Fear River (CFR), Lake Waccamaw (LW). Median GenX concentration was significantly higher in BHI and CFR alligators than LW samples (Guillette et al. 2022).