Concentrations of persistent organic pollutants in plasma from two species of turtle from the Tennessee River Gorge

Abstract

Persistent organic pollutants (POPs) are characterized by their resistance to degradation, biomagnification, global transport, and adverse toxicological effects. The goal of this study was to determine baseline concentrations of several classes of POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and polybrominated diphenyl ethers (PBDEs) in two turtle species, the Cumberland slider ( Trachemys scripta troosti) and the common musk turtle ( Sternotherus odoratus) from the Tennessee River Gorge. Plasma samples from five male and five female adults of each species were analyzed for concentrations of 83 PCB congeners, six DDT compounds, four toxaphene congeners, 18 additional pesticides, pentachlorobenzene, octachlorostyrene, and 28 PBDE congeners using gas chromatography/mass spectrometry. In both species, total PCBs were the predominant contaminant class, at approximately 10-fold higher concentration than p,p′-DDE, total PBDEs, and total chlordanes. Mirex, dieldrin and one toxaphene congener (Parlar 50) were also detected at even lower concentrations. The female turtles had lower concentrations of some contaminants (PCB 153 + 132, oxychlordane, mirex, PBDE 153, PBDE 154, ΣPBDEs) than males, suggesting maternal transfer to eggs. Cumberland sliders had lower concentrations of PCB 138, p,p′-DDE, ΣDDTs, oxychlordane, PBDE 47, and PBDE 99 than musk turtles. The turtles had a unique PBDE pattern with PBDE 100 predominating. The POP concentrations were lower than those measured previously in other reptiles from contaminated sites where endocrine disruption has been observed. One exception was a female musk turtle with 29.9 ng g −1 p,p′-DDE (wet mass basis), which is greater than the concentrations measured in reptiles with evidence of endocrine disruption. Additional monitoring and research is necessary to determine if other species or age classes in this turtle assemblage might be at higher risk of POP accumulation, as well as to assess the potential risk of these concentrations on their health and reproduction.