Perfluorinated compounds found in African crocodiles, American alligators

Studies are first-of-their-kind examinations of PFAA levels in 'sentinel' reptile species, especially useful for investigating impacts of long-lived chemicals in the environment

Date: August 25, 2016

Source: National Institute of Standards and Technology (NIST)

American alligators and South African crocodiles populate waterways a third of the globe apart, and yet both have detectable levels of long-lived industrial and household compounds for nonstick coatings in their blood, according to two studies from researchers at the Hollings Marine Laboratory in Charleston, South Carolina, and its affiliated institutions, which include the National Institute of Standards and Technology.

Production of some compounds in this family of environmentally persistent chemicals--associated with liver toxicity, reduced fertility and a variety of other health problems in studies of people and animals--has been phased out in the United States and many other nations. Yet all blood plasma samples drawn from 125 American alligators across 12 sites in Florida and South Carolina contained at least six of the 15 perfluorinated alkyl acids (PFAAs) that were tracked in the alligator study.

The two studies are first-of-their-kind examinations of PFAA levels in "sentinel" reptile species, especially useful for investigating the impacts of long-lived chemicals in the environment. PFAAs have been used in products that include water-repellent clothes, stain repellents, waxes, nonstick pans and fire-suppressing foams.

In alligators, plasma levels of perfluorooctane sulfonate (PFOS) ranged from 1,360 to 452,000 parts per trillion. In May 2016, the Environmental Protection Agency issued a drinking-water health advisory for PFOS and another PFAA, recommending a maximum exposure level of 70 parts per trillion for one of the PFAAs or the sum of the two. High PFOS levels reported for alligators at several sites may suggest the need to test drinking water for contamination at those locations, according to the researchers.

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