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Accumulation of persistent organic pollutants (POPs) in marine mammals is of great concern and is associated with declining populations. The concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in blubber of finless porpoises (Neophocaena asiaeorientalis) collected from Korean coastal waters in 2010 and 2015, to assess the concentrations, time trends, and ecotoxicological effects. Among the POPs measured, DDTs were detected at the highest concentrations, followed by PCBs and PBDEs. Significant age- and sex-dependent accumulation of POPs was evident for porpoises collected in 2010, but not for those collected in 2015. This finding may be a function of stabilization of POP concentrations over time. In our study, accumulation patterns of POPs were dependent on consumption patterns and physico-chemical properties of the contaminants, and on the metabolism in the porpoises. Significant reductions of POPs were found between 2003 and 2010, likely reflecting the impact of domestic and global regulation of POPs. However, no changes in most POPs were found between 2010 and 2015, suggesting a trend toward stabilization. Approximately 10 % and 27 % of porpoises exceeded previously proposed threshold levels for PCBs and DDTs, respectively, implying a potential health risk.

Data on the concentrations and accumulation profiles of polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in cetaceans are scarce. In this study, concentrations and accumulation profiles of PCDD/Fs and DL-PCBs were measured in the blubber of finless porpoises ( Neophocaena phocaenoides ) collected from Korean coastal waters. Total dioxin-like toxic equivalent (TEQ) concentrations (6.5–31 pg/g lipid weight) in finless porpoises were lower than those reported for cetaceans and pinnipeds from other countries. Significant gender-specific differences were found in the concentrations and accumulation profiles of PCDD/Fs and DL-PCBs and this difference was associated with maternal and lactation transfer of contaminants from mature females to their fetus. All of the PCDD/F homologue groups were detected in all of the samples and the proportions of PCDFs were higher than those of PCDDs. The dominant congeners found in finless porpoise blubber were 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF and OCDD for PCDD/Fs and PCB 118 for DL-PCBs. The accumulation profiles of PCDD/Fs in finless porpoise in our study were different from those found for cetaceans from other countries. Total TEQ levels in finless porpoises in Korea were below the suggested threshold values for adverse health effects in marine mammals.

Information on the occurrence and distribution of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in marine mammals from Korean coastal waters is not available to date. This is the first study to investigate concentrations and accumulation of PCBs, OCPs, and PBDEs in liver and blubber of minke whales and common dolphins from Korean coastal waters. The concentrations of organochlorines and PBDEs in blubber were several times higher than in liver. The concentrations of PCBs and OCPs were generally low, but the concentrations of PBDEs were similar to those reported for cetaceans elsewhere. The accumulation profiles of OCPs differed between liver and blubber, while the profiles of PCBs and PBDEs were relatively similar in both tissues. The concentrations of PCBs, DDTs, CHLs and PBDEs in common dolphins were significantly higher than those in minke whales, while there were no inter-species differences for HCHs and HCB. The predominant OCP, PCB and PBDE congeners in cetaceans were p,p′-DDE, PCB 153 and BDE 47, respectively. The concentrations of PCBs and DDTs in Korean cetaceans were close to the threshold for adverse health effects.