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Whether perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) are responding to legislative restrictions and showing decreasing trends in top marine predators that range across the eastern North Pacific Ocean is unclear. Here, we examined longer-term temporal trends (1973-2019) of 4 PFSAs and 13 PFCAs, as well stable isotopes of δ 13 C and δ 15 N, in the eggs of 4 seabird species sampled along a nearshore-offshore gradient; double-crested cormorants ( Nannopterum auritum ), pelagic cormorants ( Urile pelagicus ), rhinoceros auklets ( Cerorhinca monocerata ), and Leach's storm-petrels ( Hydrobates leucorhous ) from the Pacific coast of British Columbia, Canada. PFOS was the most abundant PFSA (79-94%) detected in all eggs regardless of colony and year, with the highest concentrations, on average, measured in auklet eggs (mean = 58 ng g -1 , range = 11-286 ng g -1 ww). Perfluoroundecanoic acid (PFUdA) and perfluorotridecanoic acid (PFTriDA) were the dominant long-chain PFCAs (≥30% combined). The majority of PFSAs (including PFOS) are statistically declining ( p < 0.001) in the eggs of all 4 species with PFOS half-lives ranging from 2.6 to 7.8 years. Concentrations of long-chain PFCAs exhibited a trajectory comprised of linear increases and second-order declines, suggesting that the rate of uptake of PFCAs is slowing or leveling off. These trends are consistent with the voluntarily ceased production of PFSAs by 3M circa 2000-2003 and are among the first from the northeast Pacific to indicate a positive response to several regulations and restrictions on PFCAs from facility emissions and product content.

As the dominant means for control of pest rodent populations globally, anticoagulant rodenticides (ARs), particularly the second-generation compounds (SGARs), have widely contaminated nontarget organisms. We present data on hepatic residues of ARs in 741 raptorial birds found dead or brought into rehabilitation centers in British Columbia, Canada, over a 30-year period from 1988 to 2018. Exposure varied by species, by proximity to residential areas, and over time, with at least one SGAR residue detected in 74% of individuals and multiple residues in 50% of individuals. By comparison, we detected first-generation compounds in <5% of the raptors. Highest rates of exposure were in barred owls (Strix varia), 96%, and great horned owls (Bubo virginianus), 81%, species with diverse diets, including rats (Rattus norvegicus and Rattus rattus), and inhabiting suburban and intensive agricultural habitats. Barn owls (Tyto alba), mainly a vole (Microtus) eater, had a lower incidence of exposure of 65%. Putatively, bird-eating raptors also had a relatively high incidence of exposure, with 75% of Cooper's hawks (Accipiter cooperii) and 60% of sharp-shinned hawks (Accipiter striatus) exposed. Concentrations of SGARs varied greatly, for example, in barred owls, the geometric mean ∑SGAR = 0.13, ranging from <0.005 to 1.81 μg/g wet weight (n = 208). Barred owls had significantly higher ∑SGAR concentrations than all other species, driven by significantly higher bromadiolone concentrations, which was predicted by the proportion of residential land within their home ranges. Preliminary indications that risk mitigation measures implemented in 2013 are having an influence on exposure include a decrease in mean concentrations of brodifacoum and difethialone in barred and great horned owls and an increase in bromodialone around that inflection point. Environ Toxicol Chem 2022;41:1903-1917. © 2022 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada., (© 2022 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.)

To examine the spatial, and temporal variation and potential sources of pesticide concentrations, primarily neonicotinoid insecticides, in hummingbirds in western Canada, we sampled their cloacal fluid from sites in British Columbia and Saskatchewan, Canada in 2017-2018. At a sub-sample of those sites, we also measured pesticides in honey bee (Apis mellifera) nectar, water, and sediment. We collected cloacal fluid from 5 species of hummingbirds (n = 26 sites) in British Columbia (BC) and Saskatchewan, Canada, and nectar from honey bee hives (n = 4 sites), water and sediment (n = 18 sites) in the Fraser Valley, BC. Among those, multiple types of samples were collected at 6 sites. We report the first measurement of flupyradifurone, a relatively new butenolide insecticide, in wildlife which was detected at 4.58 ng/mL in hummingbird cloacal fluid and 2.18 ng/g in honey bee nectar. We also detected three other neonicotinoids (imidacloprid, clothianidin, acetamiprid) and one metabolite desnitro-imidacloprid, and MGK264, a pesticide synergist, in our samples. Among 49 samples of cloacal fluid from rufous (Selasphorus rufus), Anna's (Calypte anna), calliope (Selasphorus calliope) black-chinned (Archilocus alexandri) and ruby-throated hummingbirds (Archilocus colubris), 26.5% (n = 13) contained neonicotinoids. Maximum pesticide concentrations in hummingbirds, water and sediment were found in samples collected in the Fraser Valley, BC within 0.5 km of conventionally sprayed blueberry fields (CSBF) but highest levels in honey bee nectar were detected at a site 1.5 km from a CSBF. Imidacloprid in honey bee nectar at one site exceeded concentrations (>1 ng/g) that can sublethally affect worker bee foraging efficiency. In water, imidacloprid concentrations at another site exceeded Canadian guidelines (230 ng/mL) for the protection of aquatic invertebrates., Competing Interests: Declaration of competing interest We wish to state that there was no conflict of interest in regards to this manuscript., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

To measure exposure to neonicotinoid and other pesticides in avian pollinators, we made novel use of cloacal fluid and fecal pellets from rufous (Selasphorus rufus) and Anna's (Calypte anna) hummingbirds living near blueberry fields in the Fraser River Valley and Vancouver Island, British Columbia, Canada. To examine on-farm exposure to pesticides in invertebrate pollinators, we also collected bumble bees native to Canada (Bombus mixtus, Bombus flavifrons, and Bombus melanopygus), their pollen, and blueberry leaves and flowers from within conventionally sprayed and organic blueberry farms. By sites and sample type, the results reported in the present study represent pooled samples (n = 1). In 2015 to 2016, the combined concentration of the neonicotinoid insecticides imidacloprid, thiamethoxam, and clothianidin detected in hummingbird cloacal fluid from sites near conventionally sprayed blueberry fields was 3.63 ng/mL (ppb). Among the 18 compounds measured in fecal pellets, including one neonicotinoid (imidacloprid), only piperonyl butoxide was detected (1.47-5.96 ng/g). Piperonyl butoxide is a cytochrome P450 inhibitor applied with some insecticides to increase their toxic efficacy. Only diazinon was detected in bumble bees (0.197 ng/g), whereas diazinon (1.54-1.7 ng/g) and imidacloprid (up to 18.4 ng/g) were detected in pollen collected from bumble bees including the bees from organic sites located near conventionally sprayed blueberry farms. Imidacloprid was also detected at 5.16 ng/g in blueberry flowers collected 1 yr post spray from 1 of 6 conventionally sprayed blueberry farms. Environ Toxicol Chem 2018;37:2143-2152. © 2018 SETAC., (© 2018 SETAC.)