[image-1]With the start of another alligator season almost upon South Carolina, local researchers have attempted to determine if a pervasive contaminant may pose a health risk to hunters.

Alligator season in South Carolina begins Sept. 9 and lasts until Oct. 14. Charleston Harbor has been identified as having the highest levels of PFASs (per- and polyfluoroalkyl substances) in the nation. Although present throughout the environment, this family of chemicals used in foams, carpets, non-stick cookware, and food packaging, has been found in higher concentrations among the Charleston area’s dolphin populations, as well as other local marine species. Although the true impact of these contaminants on human health have yet to be fully understood, PFASs have been linked to immune suppression, reproductive problems, developmental abnormalities, liver damage, and increased mortality in laboratory animals.

Following negotiations with the Environmental Protection Agency, 3M announced in the early 2000s that the corporation would voluntarily phase out the production of the most common varieties of these chemical compounds (PFOA and PFOS), but PFASs continue to be found in high supply in the Charleston area. Serving as great indicators of the contaminants present in an area due to their long lifespan, South Carolina’s alligators show just how plentiful these chemicals are in the local environment, which is of special concern considering that more than 11,000 pounds of alligator meat was harvested from recreational hunts in 2013 and more than 9,000 pounds was harvested in 2015.

Public alligator hunting seasons first opened in South Carolina in 2007, with the eastern portion of the state divided into four designated regions: the Midlands, the Pee Dee, Southern Coastal, and the Middle Coast, which encompasses the Charleston, Dorchester, and Berkeley counties. These hunting regions designated by the state Department of Natural Resources allowed researchers at the College of Charleston, MUSC, Clemson, University of Georgia, and National Institute of Standards and Technology at the Hollings Marine Laboratory to gain a better understanding of which portions of the state may be home to the greatest concentrations of PFAAs (perflourinated alkyl acids).

“Concentrations of one or all compounds varied significantly across sampling locations, with alligators harvested in the Middle Coastal hunt unit having the highest PFOS concentrations,” wrote former CofC graduate student Jessica Tipton and fellow researchers in an article in the Journal of Environmental Sciences. “Alligators harvested specifically from Berkeley County, S.C. (located in the Middle Coastal hunt unit) had the highest PFOS concentrations and the greatest number of PFAAs detected. The site-specific nature of PFAA concentrations in alligator meat observed in this study suggests a source of PFAA contamination in Berkeley County, S.C.”
[image-2] According to researchers who examined tail meat from harvested alligators across the state in 2015, the Midlands and Middle Coastal regions had the highest levels of PFAAs, indicating a common source of contamination within the shared watershed. Still, the Charleston area remains a hot spot for contamination.

“Despite the phase-out of many PFAAs used by industry, the elevated PFAA concentrations found in the Charleston Harbor area could indicate that sources of contamination to this watershed are potentially active, there is transport and accumulations of PFAAs in this area from an upstream locations, and/or there is accumulation of PFAAs in a closed system,” researchers wrote. “The Cooper River runs through Berkeley County, S.C., receiving water from Lake Moultrie within the Midlands unit, and flowing toward the coast into Charleston Harbor. When alligator harvest locations were separated by county for further site-specific investigation, Berkeley County within the Middle Coastal hunt unit exhibited the highest PFDA, PFTriA, and PFOS concentrations of the four counties included in the study.”

Considering that elevated levels of contaminants were found in meat harvested by South Carolina hunters for the purpose of consumption, researchers conducted a follow-up study into the eating habits of local alligator hunters. A survey of hunters found that a majority of respondents planned to consume locally harvested alligator meat at least once a month, with almost half planning to share alligator meat with their children under the age of 15.

No hunters reported plans to eat alligator meat in levels that would exceed recommended levels, but researchers warned that exposure to a mixture of PFAAs, like that found in South Carolina alligators, coupled with site specific exposures should be considered when determining appropriate guidelines for vulnerable populations such as children and pregnant women. The S.C. Department of Natural Resources currently recommends eating no more than 8 ounces of alligator meat per week to avoid the risk of mercury poisoning.

According to Dr. Jessica Reiner at the National Institute of Standards and Technology who contributed to the studies, the next step for researchers is to look at the other contaminants that may be present in the sample collected. Four of the five alligator meat samples with the highest levels of PFOS, which have specifically been linked to immune suppression and increased mortality in lab mice, were taken from Berkeley County, with the highest rates found in an alligator harvested from the Cooper River.

“This study also provides evidence that the Charleston Harbor may be receiving PFAAs from potential inputs higher (upstream) in the watershed such as the Cooper River, indicated by the highest concentrations of PFAAs in samples from this waterbody,” researchers concluded. “Many potential sources of PFAAs exist along the Cooper River, including industry, development, a naval station, and wastewater treatment outflows, all of which have been previously identified as sources of PFAA pollution.”


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