Multi-year assessment (2006–2015) of persistent organic pollutant concentrations in blubber and muscle from Western Arctic bowhead whales (Balaena mysticetus), North Slope, Alaska

Temporal Trends of Persistent Organic Pollutants in Sarasota Bay Common Bottlenose Dolphins (Tursiops truncatus)

“…The reason for relatively high rate of decline in nursing dolphins is not clear. Decline for the three significantly decreasing groups were slightly faster than those seen in arctic biotic time trend data sets (ranging from −2.0 to −2.6%) (Rigét et al, 2019;Bolton et al, 2020), however only 36% of data sets showed significant declines and two data sets showed significant increases in HCB with time. Similarly, temporal trends of HCB in air at different arctic monitoring stations showed both increasing and declining HCB trends depending on location again suggesting environmental concentrations are likely supported by ongoing HCB emissions (Hung et al, 2016).…”

“…The largest decline was observed for adult females (−9.2% per year) and the smallest decline was for nursing calves (−4.0% per year). Overall, rates of decline of DDTs in Sarasota bottlenose dolphins were less than those observed in Great Lakes fish, although rates of decline in fish species were somewhat variable while rates of decline in arctic fauna averaged −4.2 to −6.0% per year (Table 3; Rigét et al, 2019;Bolton et al, 2020). DDT in adult females and males, while differing markedly in lipid-based concentrations, declined at similar rates likely reflecting declining rates in forage (Table 3).…”

“…Relatively large declines in dieldrin were observed in the Great Lakes with the largest observed in Lake Huron lake trout (−16% per year; Table 3). Declines in arctic fauna were reported to be −3% per year on average in the 10 data sets showing significant temporal changes (Rigét et al, 2019;Bolton et al, 2020).…”

“…PCB declines in the Arctic are dependent on location with the highest rates (up to −5% per year) observed in seals for more eastern than western locations (Rigét et al, 2019). PCB levels also decreased with time in blubber of bowhead whales (Balaena mysticetus) harvested near the North Slope, Alaska from 2006 to 2015, though the decline was not significant (Bolton et al, 2020).…”

“…Many temporal trend studies of aquatic biota capture the use restrictions of PBDEs often showing increasing trends up to the early 2000s followed by declines (Braune et al, 2015). Long-term (>10 year) data sets spanning this period often do not show significant temporal trends as biotic concentrations rise and then fall during the time series (Rigét et al, 2019;Bolton et al, 2020). Such a pattern was not apparent in the current data set with concentrations steadily declining across the time frame of when PBDEs were phased out of production in the early 2000s (Figures 1-4).…”