Sewage effluents contain pharmaceuticals, personal care products and industrial chemicals, exposing aquatic organisms to complex mixtures. The consequences of exposure to combinations of different classes of drugs in fish are largely unknown. In this study, we exposed adult zebrafish (Danio rerio) males and females for two weeks to low, environmentally relevant concentrations of the endocrine disrupting chemical 17α-etinylestradiol (EE₂) and the selective serotonin re-uptake inhibitor (SSRI) citalopram, alone and in combination, and analyzed behaviors of importance for population fitness, scototaxis (light/dark preference), the novel tank test and shoal cohesion. Control water contained 0.4 ng/L EE₂ and the measured exposure concentrations were 0.9 ng/L EE₂ (nominal 0.1) and 1 ng/L EE₂ (nominal 0.5). The measured concentrations of citalopram were 0.1 (nominal 0.1) and 0.4 μg/L (nominal 0.5). Both EE₂ exposures increased anxiety in males in the scototaxis test, with significantly longer latency periods before entering and fewer visits to the white zone of the tank. The combined exposures (0.9 ng/L EE₂ + 0.1 μg/L citalopram and 1 ng/L EE₂ + 0.4 μg/L citalopram) resulted in abolishment of effects of EE₂, with shorter latency period and more transitions to white than for fish exposed to EE₂ alone. In the novel tank test, the results surprisingly indicated lower anxiety after both EE₂ and citalopram exposure. Significantly more transitions to the upper half of the tank observed in males exposed to 0.1 μg/L citalopram alone compared to control males. Males exposed to EE₂ (0.9 ng/L) had shorter latency period to the upper half. Combination exposure resulted in a longer latency and fewer transitions to the upper half compared to both control, EE₂- and citalopram-exposed males. Males exposed to the combination spent significantly less time in the upper half than males EE₂ or citalopram-exposed males. Females exposed to 1 ng/L EE₂ had fewer transitions to the upper half than the control group and females exposed to 0.4 μg/L citalopram. In the shoaling test, males exposed to 0.1 μg/L citalopram + 0.9 ng/L EE₂ showed more transitions away from peers than males exposed to 0.1 μg/L citalopram alone. In conclusion, low concentrations of EE₂, closely above the predicted no effect concentration (NOEC) of 0.1 ng/L, created anxiety-like behavior in zebrafish males. Citalopram showed marginal effects at these low concentrations but in the combination exposure the behavioral effects of EE₂ were abolished. This is an initial effort to understand the effects of cocktails of anthropogenic substances contaminating aquatic environments.

污水中包含药物，个人护理产品和工业化学品，使水生生物暴露于复杂的混合物中。暴露于鱼类中不同类别药物组合的后果在很大程度上是未知的。在这项研究中，我们将成年斑马鱼（Danio rerio）的雄性和雌性暴露于环境相关浓度低的内分泌干扰化学物质17α-乙炔雌二醇（EE ₂）和选择性5-羟色胺再摄取抑制剂（SSRI）西酞普兰两周并结合起来，分析了对于人口适应性，苏格兰性（浅色/深色偏好），新颖的坦克测试和浅滩凝聚力具有重要意义的行为。对照水含有0.4 ng / L EE ₂，测得的暴露浓度为0.9 ng / L EE₂（标称值0.1）和1 ng / L EE ₂（标称值0.5）。西酞普兰的测量浓度为0.1（标称值为0.1）和0.4μg/ L（标称值为0.5）。两次在scototaxis测试中，两次EE ₂暴露都增加了男性的焦虑感，进入前的潜伏期明显更长，而对水箱白色区域的探访次数则更少。联合暴露（0.9 ng / L EE ₂  + 0.1μg/ L西酞普兰和1 ng / L EE ₂  + 0.4μg/ L西酞普兰）消除了EE ₂的作用，与传统方法相比，具有更短的潜伏期和更多的向白色过渡单独暴露于EE _2的鱼类。在新型油罐测试中，结果出乎意料地表明，两次EE ₂后焦虑均降低和西酞普兰暴露。与对照雄性相比，单独暴露于0.1μg/ L西酞普兰的雄性中观察到明显更多的向水箱上半部的过渡。暴露于EE ₂（0.9 ng / L）的男性的上半身潜伏期较短。与对照，EE ₂和暴露于西酞普兰的雄性相比，组合暴露导致更长的潜伏期和更少的过渡到上半部分。男性与男性EE ₂或暴露于西酞普兰的男性相比，在上半身中花费的时间明显更少。暴露于1 ng / L EE _2的雌性向上半部分的迁移少于对照组，而暴露于0.4μg/ L西酞普兰的雌性则更少。在浅滩测试中，雄性暴露于0.1μg/ L西酞普兰+ 0.9 ng / L EE₂显示，与仅暴露于0.1μg/ L西酞普兰的雄性相比，与同龄人的过渡要多。总之，低浓度的EE ₂远高于预期的无效应浓度（NOEC）0.1 ng / L，在斑马鱼雄性中产生了焦虑样行为。西酞普兰在这些低浓度下显示出边际效应，但在联合暴露中，EE ₂的行为效应被消除。这是了解人类活动物质混合物污染水生环境的初步努力。