Evaluation of Emerging Contaminants and Biochemical Parameters in the Blood Plasma of Wild American Alligators (Alligator mississippiensis).

Abstract

Pollution by pharmaceuticals and industrial chemicals has received increased attention due to their environmental persistence and ecotoxicity as emerging contaminants (ECs). American alligators (Alligator mississippiensis) are top predators in the coastal aquatic ecosystems of the Gulf of Mexico and are a sentinel species for ecosystem health due to their longevity and high trophic position. However, knowledge on the extent of ECs exposures and likely health impacts on alligators is scarce. This study measured select ECs and blood biochemistry parameters in alligator plasma opportunistically sampled at the Rockefeller Wildlife Refuge in southwest Louisiana. The analysis showed the prominent occurrence of 6 ECs in the plasma: amphetamine (AMP), atenolol (ATN), ketoprofen (KTP), naproxen (NPR), nicotine (NCT), and perfluorooctane sulfonate (PFOS). AMP and PFOS were most prevalently detected in the plasma samples (95% and 100% detection frequency, respectively), and exhibited the highest concentrations (mean ± SEM; AMP: 7.05 ± 3.02 ng/mL, PFOS: 5.95 ± 0.57 ng/mL). The detection of the other ECs ranged from 46 - 69% and with mean concentrations approximately an order of magnitude lower than that of PFOS or AMP. While the biochemistry parameters were all within physiologically acceptable ranges, partial redundancy and correlation analyses suggested positive correlations between the total number of detected pharmaceuticals, ATN, and PFOS, with biochemical parameters associated with liver, kidney, and muscle injury; and endocrine disruption. This study reports on the exposure of alligators to ECs and identifies likely biomarkers of exposure and adverse effects.