Environment and Climate Change Canada, Wildlife Research Division, Delta, British Columbia, Canada.
Department of Natural Resource Sciences, McGill University, Sainte Anne-de-Bellevue, Quebec, H3A 0G4, Canada.
Environ Pollut. 2024 Dec 15;363(Pt 1):125099. doi: 10.1016/j.envpol.2024.125099. Epub 2024 Oct 10.
Using glaucous-winged gull (Larus glaucescens) eggs from Canada's Pacific coast, we investigated spatial and temporal trends (2008-2022) of a suite of legacy and emergent contaminants, including 16 perfluoroalkyl substances (PFAS), 15 polybrominated diphenyl ethers (PBDEs), 7 alternative halogenated flame retardants (AHFRs), total mercury (THg), as well as stable isotopes of carbon (δC) and nitrogen (δN) to control for diet. Legacy organochlorines (OCs) were also measured in eggs in 2020 for a preliminary human health risk assessment (HHRA). Between 2008 and 2022, glaucous-winged gull eggs from more urban-influenced colonies (Mandarte Island) were up to ∼2x more contaminated with PFAS, PBDEs, AHFRs, and THg than eggs from the offshore colony (Cleland Island), suggesting different source regions and dietary exposures. Concentrations of ΣPBDEs declined linearly among colonies (p < 0.001), consistent with several North American phase-outs and regulatory restrictions dating back to the early/mid 2000s. Conversely, temporal trends for PFOS, ΣPFCAs, ΣAHFRs, and THg were characterized by a combination of second-order declines and non-linear increases in recent years. After correcting THg for dietary shifts using δN, THg concentrations followed a U-shaped trend at Mandarte and Cleland Islands, while those at Mitlenatch Island remained relatively constant over time. Increasing trends for some contaminants coincided with both an increase in δC and δN. For the HHRA, all gull eggs collected in 2020 had hazard quotients (HQs) < 0.2, indicating no foreseeable risk or harm for First Nations consumers for certain contaminants. Our findings indicate that spatio-temporal trends of persistent contaminants in Pacific glaucous-winged gull eggs are influenced by a combination of factors, including the impact of regulations on anthropogenic emissions, coupled with changes in foraging behaviour and food-web structure.
利用来自加拿大太平洋沿岸的黑背鸥（Larus glaucescens）卵，我们研究了一套包括 16 种全氟烷基物质（PFAS）、15 种多溴二苯醚（PBDE）、7 种替代卤代阻燃剂（AHFR）、总汞（THg）以及碳（δC）和氮（δN）的稳定同位素在内的污染物在空间和时间上的趋势（2008-2022 年），以控制饮食。2020 年还测量了卵中的 legacy 有机氯（OCs），以进行初步的人类健康风险评估（HHRA）。在 2008 年至 2022 年间，来自受城市影响更大的 Mandarte 岛的黑背鸥卵中 PFAS、PBDE、AHFR 和 THg 的污染程度比来自偏远的 Cleland 岛的卵高了 2 倍左右，这表明它们有不同的来源区域和饮食暴露途径。在各个鸟群中，ΣPBDEs 的浓度呈线性下降（p<0.001），这与 21 世纪初开始的几项北美淘汰和监管限制一致。相反，PFOS、ΣPFCAs、ΣAHFR 和 THg 的时间趋势则表现为，近年来既有二阶下降，也有非线性上升。在用 δN 对饮食变化进行校正后，Mandarte 和 Cleland 岛上的 THg 浓度呈 U 型趋势，而 Mitlenatch 岛上的 THg 浓度则随着时间的推移保持相对稳定。一些污染物的上升趋势与 δC 和 δN 的上升同时出现。在 HHRA 中，2020 年收集的所有海鸥卵的危害系数（HQ）均<0.2，这表明对于某些污染物，食用这些卵的原住民消费者不会面临可预见的风险或危害。我们的研究结果表明，太平洋黑背鸥卵中持久性污染物的时空趋势受到多种因素的影响，包括法规对人为排放的影响，以及觅食行为和食物网结构的变化。
