The Neurotox Lab, School of Science, RMIT University, Melbourne, VIC 3083, Australia.
School of Biological Sciences, Monash University, VIC 3800, Australia.
Sci Total Environ. 2022 Mar 25;814:152731. doi: 10.1016/j.scitotenv.2021.152731. Epub 2021 Dec 30.
Contamination of the environment by pharmaceutical pollutants poses an increasingly critical threat to aquatic ecosystems around the world. This is particularly true of psychoactive compounds, such as antidepressant drugs, which have become ubiquitous contaminants and have been demonstrated to modify aquatic animal behaviours at very low concentrations (i.e. ng/L). Despite raising risks to the hydrosphere, there is a notable paucity of data on the long term, multigenerational effects of antidepressants at environmentally realistic concentrations. Moreover, current research has predominantly focused on mean-level effects, with little research on variation among and within individuals when considering key behavioural traits. In this work, we used a multigenerational exposure of a freshwater snail (Physa acuta) to an environmentally relevant concentration of the antidepressant fluoxetine (mean measured concentration: 32.7 ng/L, SE: 2.3). The snails were allowed to breed freely in large mesocosm populations over 3 years. Upon completion of the exposure, we repeatedly measured the locomotory activity (624 measures total), reproductive output (234 measures total) as well as morphometric endpoints (78 measures total). While we found no mean-level differences between treatments in locomotory activities, we did find that fluoxetine exposed snails (n = 46) had significantly reduced behavioural plasticity (i.e. V; within-individual variation) in activity levels compared to unexposed snails (n = 32). As a result, fluoxetine exposed snails demonstrated significant behavioural repeatability, which was not the case for unexposed snails. Further, we report a reduction in egg mass production in fluoxetine exposed snails, and a marginally non-significant difference in morphology between treatment groups. These results highlight the potential detrimental effects of long-term fluoxetine exposure on non-target organisms at environmentally realistic dosages. Additionally, our findings demonstrate the underappreciated potential for psychoactive contaminants to have impacts beyond mean-level effects, with consequences for population resilience to current and future environmental challenges.
药物污染物对环境的污染对全球水生生态系统构成了日益严重的威胁。这在精神活性化合物（如抗抑郁药）方面尤其如此，这些化合物已经成为无处不在的污染物，并已被证明在非常低的浓度（即 ng/L）下改变水生动物的行为。尽管这些污染物对水圈构成了风险，但关于在环境现实浓度下抗抑郁药的长期、多代影响的数据却明显不足。此外，目前的研究主要集中在平均水平的影响上，而在考虑关键行为特征时，个体之间和个体内部的变异研究甚少。在这项工作中，我们使用了一种淡水蜗牛（Physa acuta）的多代暴露实验，以研究环境相关浓度的抗抑郁药氟西汀（平均测量浓度：32.7 ng/L，SE：2.3）。蜗牛在大型中观种群中自由繁殖了 3 年。暴露实验完成后，我们反复测量了它们的运动活性（共 624 次测量）、繁殖输出（共 234 次测量）以及形态学终点（共 78 次测量）。虽然我们在运动活性方面没有发现处理组之间的平均水平差异，但我们确实发现，与未暴露的蜗牛相比，氟西汀暴露的蜗牛（n=46）的活动水平的行为可塑性（即 V；个体内变异）显著降低。因此，氟西汀暴露的蜗牛表现出显著的行为可重复性，而未暴露的蜗牛则没有。此外，我们还报告了氟西汀暴露的蜗牛产卵量减少，以及处理组之间形态学的差异略有非显著性。这些结果强调了在环境现实剂量下，长期氟西汀暴露对非目标生物可能产生的潜在有害影响。此外，我们的研究结果表明，精神活性污染物具有超出平均水平影响的潜在影响，这可能对当前和未来环境挑战下的种群恢复力产生影响。
