Polybrominated diphenyl ethers (PBDEs), a class of additive flame retardants, are temporally increasing in wildlife tissues and capable of disrupting normal endocrine function. We determined whether in ovo and post-hatch exposure of captive American kestrels (Falco sparverius) to environmentally relevant PBDEs alter thyroid, retinol, and oxidative stress measures. Control eggs were injected with safflower oil and subsequent nestlings fed the same vehicle; dosed eggs received PBDE congeners (BDE-47, -99, -100, -153), which mainly comprise the Penta-BDE commercial mixture, dissolved in safflower oil at concentrations (1500 ng/g total [Σ] PBDEs) approximating those in Great Lakes gull eggs. Nestlings hatching from dosed eggs were orally exposed for 29 days to variable ΣPBDE concentrations that are similar to levels reported in tissues of Great Lakes trout (100 ng/g). Treatment kestrels had lower plasma thyroxine (T₄), plasma retinol, and hepatic retinol and retinyl palmitate concentrations, but unaltered triiodothyronine (T₃) concentrations and thyroid glandular structure. BDE-47, -100, and -99 were negatively associated with plasma T₄, plasma retinol (BDE-100, -99) and hepatic retinol (BDE-47). Despite an antioxidant-rich diet, PBDE exposure induced hepatic oxidative stress, particularly in females, with an increased hepatic GSSG:GSH ratio, a marginal increase in lipid peroxidation, and increased oxidized glutathione. Positive associations were found between concentrations of BDE-183 and thiols and, in males, between BDE-99 and reduced GSH, but a negative association occurred between BDE-99 and TBARS. Subsequently, concentrations of PBDE congeners in wild birds may alter thyroid hormone and vitamin A concentrations, glutathione metabolism and oxidative stress.

Global climate change-driven shifts in physical and ecological processes may alter POPs concentrations in Arctic food webs.

Eleven organophosphate esters (OPEs) were detected in surface water and sediment samples from yearly sampling (2013–2018) in the Canadian Arctic. In water samples, ∑chlorinated-OPEs (Cl-OPEs) concentrations exceeded ∑non-chlorinated-OPEs (non-Cl-OPEs) with median concentrations of 10 ng L^–1 and 1.3 ng L^–1, respectively. In sediment samples, ∑Cl-OPEs and ∑nonchlorinated-OPEs had median concentrations of 4.5 and 2.5 ng g^–1, respectively. High concentrations of OPEs in samples from the Mackenzie River plume suggest riverine discharge as an OPE source to the Canadian Arctic. The prevalence of OPEs at other sites is consistent with long-range transport. The OPE inventory of the Canadian Arctic Ocean representative of years 2013–2018 was estimated at 450–16,000 tonnes with a median ∑₁₁OPE mass of 4100 tonnes with >99% of the OPE inventory estimated to be in the water column. These results highlight the importance of OPEs as water-based Arctic contaminants subject to long-range transport and local sources. The high OPE inventory in the water column of the Canadian Arctic Ocean points to the need for international regulatory mechanisms for persistent and mobile organic contaminants (PMOCs) that are not covered by the risk assessment criteria of the Stockholm Convention.