Accumulation and time trends (2003–2015) of persistent organic pollutants (POPs) in blubber of finless porpoises (Neophocaena asiaeorientalis) from Korean coastal waters

[Display omitted] •Significant age- and sex-dependent accumulation of POPs was found in finless porpoises.•Maternal transport preferentially occurred for lower-molecular-weight POPs.•POP concentrations in porpoises decreased significantly from 2003 to 2010.•Almost all POP concentrations in porpoises stabilized during the period of 2010–2015.•Approximately 10–27 % species exceeded ecotoxicological thresholds for PCBs and DDTs. 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.