Pedersen Adam F, Dietz Rune, Sonne Christian, Letcher Robert J, Roos Anna M, Simon Malene, Rosing-Asvid Aqqalu, Ferguson Steven H, McKinney Melissa A
Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
Department of Ecoscience, Arctic Research Centre, Aarhus University, Roskilde DK-4000, Denmark.
Sci Total Environ. 2023 Oct 27:168158. doi: 10.1016/j.scitotenv.2023.168158.
Polar bear and toothed whales in the Arctic exhibit orders of magnitude differences in concentrations of legacy persistent organic pollutants (POPs), which may be attributed to comparisons made across regions and different time frames. These interspecific differences could be influenced by variations in biological susceptibility, including differences in xenobiotic biotransformation between polar bear, from the order Carnivora, and toothed whales, from the order Artiodactyla, as well as ecological factors, such as variation in feeding patterns. Here, we analyzed samples from subsistence-harvested toothed whales and polar bear in East Greenland collected between 2012 and 2021 and quantitatively compared interspecific differences in blubber/adipose polychlorinated biphenyl (PCB) and organochlorine (OC) pesticide concentrations. We further determined fatty acid (FA) signatures as dietary tracers to evaluate how feeding patterns influence POP concentrations relative to the influence of biological differences between taxa. Killer whale exhibited the highest mean concentrations of ΣPCBs (57.0 ± 14.0 mg/kg lw), Σdichlorodiphentlytrichloroethanes (ΣDDTs; 55.7 ± 13.1), and Σchlordanes (ΣCHLs; 23.1 ± 5.6 mg/kg lw), while polar bear showed the second highest concentrations for ΣPCBs (12.5 ± 1.3 mg/kg lw), but comparable or even lower levels of all OCs relative to narwhal and pilot whale. Linear models using FA patterns as explanatory variables for POP concentrations demonstrated that, for ΣPCBs, diet differences explained most of the variation. Conversely, biological differences explained more of the variation for most OCs, especially for DDT, for which polar bear showed the lowest concentrations despite feeding on similarly high trophic position prey as killer whale. This novel quantitative comparison confirms that significant differences in legacy POP concentrations occur among Arctic marine mammal predators. Furthermore, the drivers of these differences are contaminant-specific, with feeding patterns primarily influencing PCB concentrations, taxa-specific biological characteristics (e.g., in xenobiotic biotransformation capacity) affecting DDT concentrations, and both factors contributing to variations in other OCs.
北极的北极熊和齿鲸体内遗留持久性有机污染物（POPs）的浓度存在几个数量级的差异，这可能归因于不同地区和不同时间框架下的比较。这些种间差异可能受到生物易感性变化的影响，包括食肉目北极熊与偶蹄目齿鲸之间的异生物质生物转化差异，以及生态因素，如摄食模式的变化。在此，我们分析了2012年至2021年间在东格陵兰岛通过自给性捕捞获取的齿鲸和北极熊样本，并定量比较了它们脂肪中多氯联苯（PCB）和有机氯（OC）农药浓度的种间差异。我们还确定了脂肪酸（FA）特征作为饮食示踪剂，以评估摄食模式相对于分类群之间生物差异的影响，如何影响POPs浓度。虎鲸体内总多氯联苯（ΣPCBs）（57.0±14.0 mg/kg lw）、总滴滴涕（ΣDDTs；55.7±13.1）和总氯丹（ΣCHLs；23.1±5.6 mg/kg lw）的平均浓度最高，而北极熊体内总多氯联苯浓度（12.5±1.3 mg/kg lw）排第二，但与独角鲸和领航鲸相比，所有有机氯的含量相当甚至更低。以脂肪酸模式作为POPs浓度解释变量的线性模型表明，对于总多氯联苯而言，饮食差异解释了大部分变异。相反，生物差异解释了大多数有机氯的更多变异，尤其是滴滴涕。尽管北极熊与虎鲸一样以高营养级猎物为食，但其体内滴滴涕浓度却是最低的。这项新的定量比较证实，北极海洋哺乳动物捕食者体内遗留的持久性有机污染物浓度存在显著差异。此外，这些差异的驱动因素因污染物而异，摄食模式主要影响多氯联苯浓度，分类群特异性生物特征（如异生物质生物转化能力）影响滴滴涕浓度，这两个因素共同导致其他有机氯的变化。
