Temporal trends of brominated and fluorinated contaminants in Canadian Arctic beluga (Delphinapterus leucas)

Limited information exists regarding contemporary and historical emissions for many anthropogenic chemicals, especially for contaminants of emerging concern (CECs). This study examined temporal trends of several perfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDs) in three beluga whale (Delphinapterus leucas) populations from the Canadian Arctic (Hendrickson Island (HI), NT; Pangnirtung (PG), NU; and Sanikiluaq (SQ), NU) collected from 1982-2013. The confounding factors of animal size, age, and sex were included in the analyses, but were only significant for some CECs. The strongest temporal resolution was obtained from HI, which showed increasing trends in PBDEs (4.8%/yr) and HBCDs (2.9%/yr), and decreases in perfluoroalkylcarboxylic acids (PFCAs, -6.0%/yr). Concentrations of perfluorooctanesulfonate (PFOS) were relatively stable between 1984-2010, increasing substantially in 2011; trends in perfluorooctanesulfonamide (PFOSA) concentrations were not strictly linear over the study period. PBDE, HBCD, and PFCA trends in the HI population were opposite/different to that of many other arctic animals (e.g. polar bears) for the same time-period. Trends were inconsistent among locations, suggesting that regional differences in dietary exposure and/or sources may also impact these trends. The effects of climate change-driven processes on the exposure and distribution of CECs are currently not well understood, highlighting a need for ongoing contaminant monitoring.