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

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.