Sea turtles are exposed to persistent organic pollutants (POPs) primarily by ingesting contaminated prey and possibly from ingesting marine plastic debris that has absorbed these chemicals. Given the limited of knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure then the amount of ingested plastic would be correlated to POP concentrations accumulated in fat. To address our objectives we compared previously described amounts of ingested plastic debris to POP concentrations in fat samples from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 83 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher total dichlorodiphenyltrichloroethanes (ΣDDTs) than total PCBs (ΣPCBs), and these pelagic turtles had lower POP levels than previously reported in more nearshore sea turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is through prey. In green turtles, concentrations of some POPs were positively correlated with the amount of plastic ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather than marine debris.
Citation: Science of the Total Environment
Pub Type: Journals
Persistent organic pollutants, PCBs, DDT, pelagic Pacific, sea turtles, plastic pollution, marine debris