PCB—still a problem Until they were recognized as highly toxic and carcinogenic, polychlorinated biphenyls (PCBs) were once used widely. Their production was banned in the United States in 1978, though they are still produced globally and persist in the environment. Persistent organic compounds, like PCBs, magnify across trophic levels, and thus apex predators are particularly susceptible to their ill effects. Desforges et al. looked at the continuing impact of PCBs on one of the largest marine predators, the killer whale. Using globally available data, the authors found high concentrations of PCBs within killer whale tissues. These are likely to precipitate declines across killer whale populations, particularly those that feed at high trophic levels and are the closest to industrialized areas. Science, this issue p. 1373 Persistent polychlorinated biphenyls still contribute to killer whale declines three decades after having being banned. Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures. Using an individual-based model framework and globally available data on PCB concentrations in killer whale tissues, we show that PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. PCB-mediated effects over the coming 100 years predicted that killer whale populations near industrialized regions, and those feeding at high trophic levels regardless of location, are at high risk of population collapse. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class.

中文翻译：

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预测全球虎鲸数量因 PCB 污染而崩溃

PCB——仍然是一个问题 在被认为具有剧毒和致癌性之前，多氯联苯 (PCB) 曾经被广泛使用。它们的生产于 1978 年在美国被禁止，尽管它们仍在全球范围内生产并在环境中持续存在。持久性有机化合物，如多氯联苯，会在营养水平上放大，因此顶级捕食者特别容易受到它们的不良影响。德福吉斯等人。研究了多氯联苯对最大的海洋捕食者之一虎鲸的持续影响。作者使用全球可用的数据，在虎鲸组织中发现了高浓度的多氯联苯。这可能会导致虎鲸种群数量下降，尤其是那些以高营养水平为食并且最靠近工业化地区的虎鲸种群。科学，这个问题 p。1373 持久性多氯联苯在被禁用 30 年后仍然导致虎鲸数量减少。虎鲸 (Orcinus orca) 是世界上受多氯联苯 (PCB) 污染最严重的哺乳动物之一，这引起了人们对当前多氯联苯暴露对健康后果的担忧。使用基于个体的模型框架和虎鲸组织中 PCB 浓度的全球可用数据，我们表明 PCB 介导的对繁殖和免疫功能的影响威胁着世界上超过 50% 的虎鲸种群的长期生存能力。未来 100 年多氯联苯介导的影响预测，工业化地区附近的虎鲸种群，以及无论在何处以高营养水平觅食的虎鲸种群，都面临种群崩溃的高风险。