The global consumption of human antidepressants has steadily increased over the last years. The most widely prescribed antidepressants are the selective serotonin reuptake inhibitors (SSRIs), which have been linked to various life-history effects in nontarget organisms. We investigated the effects of the SSRI citalopram hydrobromide on the life history of the copepod Nitocra spinipes. Slight but significant developmental delay effects were observed at nominal concentrations of 0.1 and 1 µg/L, with stronger effects occurring at measured concentrations of 178 µg/L and above. At 77 µg/L and above, a significant increase in adult body length and offspring production/brood was found, although the time between brood releases remained unaffected. The pre-adult surviving fraction was significantly reduced (by 44%) at 765 µg/L. For a mechanistic evaluation of these observations, we used a bioenergetics model for N. spinipes based on the dynamic energy budget theory. Toxicokinetic and toxicodynamic submodels were used to dynamically simulate the chemical uptake and elimination, as well as dose–response relationships for hypothetical physiological modes of action and survival over time. Although none of the commonly invoked physiological modes of action, acting on assimilation, maintenance, growth, or offspring production, could explain the observed combination of effects, a newly proposed physiological mode of action acting on the process of maturation delivered correct predictions in terms of each effect's direction. The model fits could be further improved by allowing for a gentler concentration–effect slope and by adding an auxiliary physiological mode of action acting on the reproduction efficiency. The quantitative explanations provided in the present study offer a starting point for exploratory simulation studies investigating the effects of SSRIs at higher ecological levels. Environ Toxicol Chem 2021;40:1928–1939. © 2021 SETAC

中文翻译：

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使用生物能量学模型了解抗抑郁药西酞普兰在桡足类 Nitocra spinipes 中的生活史影响

过去几年，全球人类抗抑郁药的消费量稳步增长。最广泛使用的抗抑郁药是选择性5-羟色胺再摄取抑制剂（SSRIs），它与非靶标生物体的各种生活史影响有关。我们研究了 SSRI 西酞普兰氢溴酸盐对桡足类Nitocra spinipes 生活史的影响. 在 0.1 和 1 µg/L 的标称浓度下观察到轻微但显着的发育延迟效应，在测量浓度为 178 µg/L 及以上时会出现更强的影响。在 77 µg/L 及以上时，发现成年体长和后代产量/育雏显着增加，尽管育雏释放之间的时间不受影响。在 765 µg/L 时，成年前的存活率显着降低（降低了 44%）。为了对这些观察结果进行机械评估，我们使用了刺猪笼草的生物能量学模型基于动态能量收支理论。毒物动力学和毒物动力学子模型用于动态模拟化学物质的吸收和消除，以及假设的生理作用模式和随时间推移的存活率的剂量反应关系。尽管作用于同化、维持、生长或后代生产的常用生理作用模式都不能解释观察到的效果组合，但新提出的作用于成熟过程的生理作用模式在以下方面提供了正确的预测：每个效果的方向。通过允许更温和的浓度效应斜率和添加作用于繁殖效率的辅助生理作用模式，可以进一步改进模型拟合。环境毒物化学2021；40:1928–1939。© 2021 SETAC