Why alligators with orange heads are showing up around the Cape Fear region

How their orange markings will teach us more about GenX
Updated: Jun. 13, 2019 at 2:50 PM EDT
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WILMINGTON, N.C. (WECT) - If you take a walk around Greenfield Lake, or any spot alligators tend to frequent in the Cape Fear, you may notice many have orange markings on their heads.

A team of researchers from North Carolina State University has been capturing, testing, and tagging alligators across the state as part of a study to learn more about the potential health impacts Perfluorinated compounds (PFAS), like GenX, can have on animals.

“We’re looking at contaminants, but specifically perfluorinated compounds related to GenX and we are using alligators because they are actually a wonderful surrogate or indicator species for human exposures and health effects. So what we’re trying to do is find the levels of multiple different compounds, see if those levels are accumulating in their bodies, and then seeing if it’s associated with any health effects,” said Scott Belcher, a research professor at N.C. State’s Department of Biological Sciences.

Belcher’s research team is made up of postdoctoral scholar Dr. Theresa Guillett, graduate and undergraduate students, and volunteers.

“What we do is really humane and is a method that’s been proven not to cause long-term stress or cause long-term harm to the animal. We’re essentially doing the equivalent of a vet check with them. So we catch them very quickly, we immediately take a blood sample, so we can get good indicators of hormones and other chemistry from their blood. Then immediately measure them, determine their sex, and then we let them go right back into Greenfield Lake,” Belcher said.

The animals are then marked with an orange wax substance, that will last two to three weeks and is not harmful to the animal or the environment.

“We typically use a wax-based paint. As you could see, when we were capturing, it’s really hard to tell which ones we’ve caught, which ones we haven’t until we get them on shore and at that time you’re already putting a lot of stress on the animal. So what we like to do is use a quick wax-based paint to make sure we can see 'Oh wait, that’s orange. We’ve sampled that one two to three weeks ago, let’s leave it alone for now,’” Guillett said.

After the blood samples are taken, they are tested using sensitive analytical methods to determine all of the perfluorinated compounds in the blood and their concentrations. Belcher said they also run blood indicators to test the animal’s health to determine if the higher levels of PFAS are associated with any health effects.

“Right now our studies are primarily going to tell us if there are higher exposures associated with the Cape Fear River. In some cases, we also have parallel studies going on with striped bass and other fish where we actually are very close to having results showing that higher levels of the PFAS in the Cape Fear River and the striped bass are having detrimental health effects on these fish,” Belcher said.

The team started their research during the fall of 2018, right after Hurricane Florence. So far, they have found that alligators caught in Greenfield Lake have, on average, a 10 times higher concentration of PFAS in their blood than alligators tested in Lake Waccamaw in Columbus County.

This study is part of a larger network of PFAS testing being conducted by researchers across the state.

“We’re part of the PFAS testing network, which is a statewide group of researchers at universities who are looking specifically at how much of GenX and other chemicals are in the air and the water as well as some of the health effects that are going on in people. But the combined efforts of the PFAS testing network will be to come to some of these determinations and give some of the best science to regulators,” Belcher said.

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