Legacy and emerging persistent organic pollutants in sea turtles from Korean waters: Levels, profiles, and...

Sea turtles, as endangered species with their long lifespans, wide-ranging migration, and high trophic level, are effective bioindicators of marine pollution. Despite the importance of global monitoring of persistent organic pollutants (POPs) in sea turtles, research has been limited, especially in Asia. This study examined the accumulation of POPs in the livers of 44 sea turtles from Korean waters, including loggerhead (Caretta caretta) and green turtles (Chelonia mydas). The turtles accumulated the chemicals in the order PAHs > PCBs > DDTs > PBDEs > CHLs, HBCDs, hexachlorobenzene, HCHs > mirex, pentachlorobenzene. Loggerhead turtles had significantly higher levels of DDTs, HCHs, pentachlorobenzene, and PBDEs than green turtles (Wilcoxon rank sum test, p < 0.01), along with a higher proportion of bioaccumulative congeners and isomers, likely due to their primarily carnivorous diet compared to the predominantly herbivorous diet of green turtles. Conversely, HBCD levels were similar in both species, yet green turtles had a higher proportion of γ-HBCD-the dominant isomer in commercial HBCDs used as plastic additives, with lower bioaccumulation potential-likely reflecting their greater ingestion of plastic debris than loggerhead turtles. Notably, sea turtles had higher ratios of γ-HBCD to α-HBCD and HBCDs to PCBs than seabirds from Korean waters, implying greater exposure to plastic-derived POPs. This study highlights the widespread accumulation of legacy and emerging POPs, including plastic-associated chemicals, in Korean sea turtles. These findings underscore the need for global POP monitoring in sea turtles and further research on the environmental fate and impact of plastic-associated chemicals.