Although atmospheric concentrations of many conventional persistent organic pollutants (POPs) have decreased in the Arctic over the past few decades, levels of most POPs and mercury remain high since the 1990s or start to increase again in Arctic areas, especially polar bears. So far, studies generally focused on individual effects of POPs, and do not directly link POP concentrations in prey species to population-specific parameters. In this study we therefore aimed to estimate the effect of legacy POPs and mercury on population growth rate of nineteen polar bear subpopulations. We modelled population development in three scenarios, based on species sensitivity distributions (SSDs) derived for POPs based on ecotoxicity data for endothermic species. In the first scenario, ecotoxicity data for polar bears were based on the HC₅₀ (the concentration at which 50% of the species is affected). The other two scenarios were based on the HC₅ and HC₉₅. Considerable variation in effects of POPs could be observed among the scenarios. In our intermediate scenario, we predicted subpopulation decline for ten out of 15 polar bear subpopulations. The estimated population growth rate was least reduced in Gulf of Boothia and Foxe Basin. On average, PCB concentrations in prey (in μg/g toxic equivalency (TEQ)) posed the largest threat to polar bear subpopulations, with negative modelled population growth rates for the majority of subpopulations. We did not find a correlation between modelled population changes and monitored population trends for the majority of chemical-subpopulation combinations. Modelled population growth rates increased over time, implying a decreasing effect of PCBs, DDTs, and mercury. Polar bear subpopulations are reportedly still declining in four out of the seven subpopulations for which sufficient long-term monitoring data is available, as reported by the IUCN-PBSG. This implies that other emerging pollutants or other anthropogenic stressors may affect polar bear subpopulations.

尽管在过去的几十年中，北极地区许多常规持久性有机污染物（POPs）的大气浓度有所下降，但大多数POPs和汞的水平自1990年代以来一直很高，或者在北极地区，特别是北极熊中又开始增加。到目前为止，研究一般都集中在持久性有机污染物的个体影响上，并未将猎物物种中的持久性有机污染物浓度直接与种群特定的参数联系起来。因此，在这项研究中，我们旨在评估遗留的持久性有机污染物和汞对19个北极熊亚群人口增长率的影响。我们基于吸热物种的生态毒性数据，基于持久性有机污染物的物种敏感性分布（SSD），在三种情况下对种群发展进行了建模。在第一种情况下，北极熊的生态毒性数据基于HC₅₀（受影响物种的50％的浓度）。其他两种情况基于HC ₅和HC ₉₅。在各种情况下，可以观察到持久性有机污染物的影响差异很大。在我们的中间场景中，我们预测了15个北极熊亚种群中有10个亚种群的下降。布希亚湾和福克斯盆地的估计人口增长率下降最少。平均而言，猎物中的PCB浓度（以μg/ g毒性当量（TEQ）为单位）对北极熊亚种群构成最大威胁，大多数亚种群的模型人口增长率均为负数。我们没有发现大多数化学亚种群组合的模拟种群变化与监测种群趋势之间的相关性。模拟的人口增长率随时间增加，这意味着多氯联苯，滴滴涕和汞的影响减小。据IUCN-PBSG报道，据报道北极熊亚种群在七个亚种群中有四个仍在下降，而这些亚种群中有足够的长期监测数据。这意味着其他新兴污染物或其他人为压力源可能会影响北极熊的亚群。