Analysis of persistent organic pollutants (organochlorine pesticides & PCBs) in livers of leatherback sea turtles (Dermochelys coriacea) by GC-MS/MS.

Abstract

Persistent organic pollutants (POPs) including chlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) are among anthropogenic toxicological stressors of endangered leatherback sea turtles (Dermochelys coriacea). We examined livers from 17 juvenile-to-adult leatherbacks stranded along the North American east coast (2005-2014). We employed GC-MS/MS combined with an existing OCP method while validating new PCB methods, one based on Aroclor 1260 as an analytical standard and another based on specific PCB congeners (#52, 101, 118, 153, 138, 187, 183, 126, 180, 170). Validation covered linearity, limits of detection/quantitation, accuracy, precision and specificity. OCPs were found on a dry weight basis as: trans-nonachlor (n = 3), trans-chlordane (n = 5), cis-chlordane (n = 9), p,p'-DDE (n = 10), aldrin (n = 6) and dieldrin (n = 7). All bore PCBs. Those with the aldrin metabolite dieldrin had dieldrin/aldrin ratios > 1.0 indicating historical exposure. The Aroclor-based PCB method reported on total PCB exposure at concentrations averaging 46 ± 28 ppb with predominance of hexa-, hepta-, and pentachlorobiphenyls, indicating possible acquisition of the PCBs in mid-oceanic latitudes. The congener-specific approach showed the greatest prevalence of PCB #153 (16 of 16 samples). Nevertheless, the total concentration results of the two PCB methods correlated with one another as shown for heptachlorobiphenyls with a correlation coefficient of 0.826 (p < 0.001). Overall, the leatherbacks showed universal exposure to PCBs, while 12 of 17 carried between one and five of the OCPs, similar to findings of other researchers.