Data associated with 'Polar bear subpopulation declines due to legacy persistent organic pollutants – temporal and spatial trends’

Although concentrations of many conventional POPs have decreased in the Arctic over the past few decades, levels of most POPs remain high in Arctic areas, especially in top predators like polar bears (Ursus maritimus). So far, studies generally focused on individual effects only. In the study associated to these data we therefore aimed to estimate the (combined and individual) effect of legacy POPs and mercury on population growth rate of nineteen polar bear subpopulations. We modelled polar bear population development in three scenarios, based on SSDs derived for POPs based on ecotoxicity data for endothermic species.Exposure data. Data on POP residues in marine mammal species (mainly Phoca hispida, Phoca largha, Phoca groenlandica, Crystophora cristata , Erignathus barbatus, Odobenus rosmarus and Monodon monoceros), assumed to be the main prey of polar bears in the Arctic, were compiled to calculate potential changes in intrinsic growth rates of polar bear populations. POP concentrations (transformed to mg/kg wet weight (w.w.)) were obtained from a literature search using the Web of Knowledge and Google Scholar. Search strings used in queries included POPs (specific compound names (e.g. “p,p’-DDE”, or “CB-153”) or compound groups (e.g. “PCBs” or “DDTs”)) on one side, combined with Arctic species’ names (both scientific (e.g. “Phoca hispida”) and common names (e.g. “ringed seal”)) on the other. Concentrations on lipid basis were converted to wet weight (w.w.) basis, based on the reported lipid content. If no lipid concentration was reported, a lipid content of 85% was assumed for marine mammal blubber samples. To calculate the toxic equivalency of PCBs, we assumed that the planar PCB composition in marine mammal blubber was similar across all sampled individuals. In the present study, the planar PCB composition in blubber was taken from Savinov et al. 2011.All concentration data used in our simulations were collected between 1972 and 2018.Ecotoxicity data were taken from the USA EPA's ECOTOX database. Ecotoxicity data for PCB mixtures were converted to toxic equivalency values (TEQ) using updated toxic equivalency factors (TEFs) for individual dioxin-like PCB congeners from the WHO (2005), and their relative concentration in Aroclor 1242, 1254 or 1260 mixtures. Concentration data (in µg/g) of individual dioxin-like PCB congeners (PCB 77, PCB 81, PCB 105, PCB 114, PCB 118, PCB 123, PCB 126, PCB 156, PCB 157, PCB 167, PCB 169 and PCB 189) in Aroclors were taken from Wischkaemper et al. (2017) (Wischkaemper 2017).

尽管过去数十年间北极地区多种传统持久性有机污染物（Persistent Organic Pollutants，简称POPs）的浓度已有所下降，但多数POPs在北极区域的残留水平仍居高不下，尤其在北极熊（Ursus maritimus）这类顶级捕食者体内。迄今为止，相关研究大多仅聚焦于单一污染物的影响。本研究旨在评估传统持久性有机污染物与汞对19个北极熊亚种群种群增长率的联合及单独效应。我们基于恒温动物的生态毒性数据推导得到的物种敏感性分布（Species Sensitivity Distributions，SSD），构建了三种情景以模拟北极熊种群的动态变化。

暴露数据。本研究收集了北极北极熊主要猎物——多种海洋哺乳动物（主要为环斑海豹（Phoca hispida）、斑海豹（Phoca largha）、格陵兰海豹（Phoca groenlandica）、冠海豹（Crystophora cristata）、髯海豹（Erignathus barbatus）、海象（Odobenus rosmarus）及独角鲸（Monodon monoceros））体内的POPs残留数据，用以计算北极熊种群内禀增长率的潜在变化。通过Web of Knowledge与Google Scholar数据库开展文献检索，获取了以湿重（w.w.，mg/kg）计的POPs浓度数据。检索式设置为：一侧纳入POPs相关关键词（包括具体化合物名称如"p,p’-DDE"、"CB-153"或化合物类别如"多氯联苯（PCBs）"、"滴滴涕类（DDTs）"），另一侧搭配北极物种的学名（如"Phoca hispida"）与通用名（如"环斑海豹"）。基于文献报道的脂肪含量，将脂基浓度换算为湿重基准浓度；若未报告脂肪含量，则默认海洋哺乳动物鲸脂样本的脂肪含量为85%。为计算多氯联苯的毒性当量，本研究假设所有采样个体的海洋哺乳动物鲸脂中二噁英类平面多氯联苯单体的组成相似。本研究中鲸脂中二噁英类平面多氯联苯单体的组成数据取自Savinov等人2011年的研究。本模拟所用的所有浓度数据采集时间为1972年至2018年。

生态毒性数据取自美国环境保护署（United States Environmental Protection Agency，EPA）的ECOTOX数据库。针对多氯联苯混合物的生态毒性数据，我们采用世界卫生组织（WHO）2005年更新的二噁英类平面多氯联苯单体毒性当量因子（Toxic Equivalency Factors，TEFs），以及其在阿罗克洛（Aroclor）1242、1254或1260混合物中的相对占比，将其换算为毒性当量值（Toxic Equivalency，TEQ）。单个二噁英类平面多氯联苯单体（PCB 77、PCB 81、PCB 105、PCB 114、PCB 118、PCB 123、PCB 126、PCB 156、PCB 157、PCB 167、PCB 169及PCB 189）在阿罗克洛混合物中的浓度数据（单位：µg/g）取自Wischkaemper等人2017年的研究（Wischkaemper 2017）。