Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus)

Abstract

Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area.

Perfluorinated alkyl acids in plasma of American alligators (Alligator mississippiensis) from Florida and South Carolina

“…These observed differences between American and Chinese alligators may be the result of many factors, including the combination of including animals from all sites in the present study, interspecific differences in food consumption, growth rate differences, and differences in body size , as well as differences in toxicodynamics and toxicokinetics of PFAAs. In addition, differences in diet and numerous environmental variables between wild (present study) and captive alligators may influence growth and body burdens of PFAAs.…”

“…The present study is the first to quantitate PFAA concentrations in American alligators and one of the few studies to quantitate PFAAs in crocodilians [20][21][22]. All alligator samples (n ¼ 125) contained the 5 following PFAAs: PFOS (median, 11.2 ng/g; range, 1.36-452 ng/g), PFUnA (median, 1.58 ng/g; range, 0.314-18.4 ng/g), PFDA (median, 1.20 ng/g; range, 0.169-15.1 ng/g), PFNA (median, 0.528 ng/g; range, 0.155-1.40 ng/g), and PFHxS (median, 0.288 ng/g; range, 0.057-23.3 ng/g).…”

Variation in perfluoroalkyl acids in the American alligator (Alligator mississippiensis) at Merritt Island National Wildlife Refuge

“…As expected, PFOS, which is commonly found in environmental samples, was the highest measured PFAA at MINWR with a median of 185 ng/g (Houde et al, 2011). However, the PFOS measured in alligators from MINWR had a large range, 6.06 ng/g – 2140 ng/g, revealing the highest PFOS concentration yet measured in a crocodilian species (Wang et al, 2013; Bouwman et al, 2014; Christie et al, 2016). PFHxS was the second highest PFAA measured with a median of 7.96 ng/g and a range of < 0.008 ng/g to 161 ng/g.…”

“…Due to their high trophic status, long life span, and high site fidelity, crocodilians are susceptible to exposure and accumulation of environmental contaminants released (e.g., chemical application, spill, faulty disposal) or atmospherically deposited in their habitats (Rainwater et al, 2007). While numerous studies have examined accumulation of other persistent environmental contaminants (e.g., organochlorine pesticides, polychlorinated biphenyls, metals) in crocodilians (Campbell, 2003), to date, only four studies have reported PFAAs in these animals (Wang et al, 2013; Bouwman et al, 2014; Christie et al, 2016). Most recently, Bangma et al (Bangma et al, 2016) found that American alligators ( Alligator mississippiensis ) located within Merritt Island National Wildlife Refuge (MINWR), Florida, have an elevated plasma PFAA burden compared to alligators examined at a number of other sites in Florida and South Carolina (Bangma et al, 2016).…”

Analysis of PFAAs in American alligators part 1: Concentrations in alligators harvested for consumption during South Carolina public hunts

“…Few studies have been conducted on PFAA contamination levels in reptiles (Keller et al, 2012; Wang et al, 2013; Christie et al, 2016; Bangma et al, 2017a, 2017b), and all of these have used blood as a focal tissue for analysis; none have examined PFAA concentrations in other tissues, including those potentially consumed by other wildlife or humans. The American alligator ( Alligator mississippiensis ) is a highly sought after wild game species for which a hunting season has recently (2007) been established in SC.…”