Elevated exposure, uptake and accumulation of polycyclic aromatic hydrocarbons by nestling tree swallows (&ITTachycineta bicolor&IT) through multiple exposure routes in active mining-related areas of the Athabasca oil sands region

In the Athabasca Oil Sands (OS) Region, the exposure (by air, water, diet), uptake and deposition of polycyclic aromatic compounds (PACs), including parent and alkylated hydrocarbons (PAHs) and dibenzothiophenes (DEtTs), was assessed in nestling tree swallows (Tachycineta bicolor) at mining-related (051, OS2) and reference (REF) sites. The OS sites did not receive oil-sands processed waters (OSPW) and were >= 60 km from the reference sites. Most of the 42 PACs (<= 98%) were detected in all matrices. Swallows at the OS sites were exposed to higher air and water concentrations of individual PAC congeners, Sigma PACs, Sigma parent-PAHs, Sigma alkyl-PAHs and Sigma DBTs. Compared to reference nestlings (Sigma PACs: 13-27 ng/g wet weight (ww)), PACs were significantly higher in OS nestlings (31-106 ng/g ww) that also accumulated higher concentrations of major PAHs (i.e., naphthalene, C1-naphthalene, C2-naphthalene, C1-fluorenes, C2-fluorenes, C1-phenanthrenes) measured in 60% of nestlings. Uptake and deposition of PAHs in the birds muscle was related to diet (delta N-15: C1-naphthalenes, C2-naphthalenes, C1-fluorenes), water (C1-phenanthrenes), and air through inhalation and leather preening (Cl-fluorenes), but fecal concentrations were not well explained by diet or environmental concentrations. While PAH concentrations were much higher in muscle than feces, they were highly correlated (p <= 0.001 for all). Thus feces may represent a non-lethal method for characterizing PAH exposure of birds, with muscle characterizing accumulation and sources of PAH exposure. Tree swallows in the Athabasca OS Region are exposed to many PACs, accumulating higher concentrations when developing in dose proximity to mining activity through diet, aerial deposition and mining-impacted freshwater sources (e.g., wetlands). Crown Copyright (C) 2017 Published by Elsevier B.V.