Abstract：
As long-lived apex predators, marine mammal adults often accumulate alarmingly levels of environmental contaminants. Nevertheless, the accumulation and risks of these contaminants in the critical calf stage of marine mammals remain largely unknown. Here, we investigated the exposure status and health risks of 74 organohalogen contaminants (OHCs) in Indo-Pacific humpback dolphin calves (Sousa chinensis) collected from the Pearl River Estuary (PRE), China, during 2005-2019. Our findings revealed moderate levels of polychlorinated biphenyls (PCBs), medium-high levels of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), and the highest levels of polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) compared to those reported for cetaceans elsewhere. Traditional OHCs like DDTs, PCBs, and PBDEs did not exhibit significant decreasing trends in the dolphin calves despite global restrictions on these compounds, and AHFRs as emerging OHCs showed an increasing trend over the study period. Risk quotients of DDTs, HCHs, PBDEs, and PCBs in most of the dolphin samples were > 1, indicating that humpback dolphin calves may have suffered long-term threats from OHC exposure. The significant correlation observed between the traditional OHC levels and the stranding death number of the dolphin calves suggests these OHCs may impact the survival of this endangered species.
摘要：
作为长寿的顶级捕食者，海洋哺乳动物成虫经常积累惊人水平的环境污染物。然而，这些污染物在海洋哺乳动物的关键小腿阶段的积累和风险在很大程度上仍然未知。这里,我们调查了从珠江口（PRE）收集的印度太平洋座头海豚小牛（Sousachinensis）中74种有机卤素污染物（OHC）的暴露状况和健康风险，中国,2005-2019年。我们的发现揭示了中等水平的多氯联苯(PCBs)，中高水平的二氯二苯基三氯乙烷（DDTs）和六氯环己烷（HCHs），与其他地方报道的鲸类相比，多溴联苯醚(PBDEs)和替代卤化阻燃剂(AHFRs)的含量最高。像DDTs这样的传统OHCs，多氯联苯,和多溴二苯醚没有表现出显著的下降趋势，尽管这些化合物的全球限制，AHFRs作为新兴的OHCs在研究期间显示出增加的趋势。DDTs的风险商，六氯环己烷,多溴二苯醚，和多氯联苯在大多数海豚样本>1，这表明座头海豚小牛可能遭受长期威胁的OHC暴露。观察到的传统OHC水平与海豚小牛搁浅死亡人数之间的显着相关性表明，这些OHC可能会影响这种濒危物种的生存。
