Department of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy.
Research Institute on Terrestrial Ecosystems of the National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Firenze, Italy; "Emil Racovita" Institute of Speleology, Romanian Academy, Clinicilor 5, Cluj Napoca 400006, Romania.
Sci Total Environ. 2021 Dec 10;799:149461. doi: 10.1016/j.scitotenv.2021.149461. Epub 2021 Aug 4.
Diclofenac (DCF) is one of the most widespread pharmaceutical compounds found in freshwaters as a pseudo-persistent pollutant due to its continuous release from point and diffuse sources, being its removal in Wastewater Treatment Plants incomplete. Moreover, DCF is particularly persistent in interstitial habitats and potentially toxic for the species that spend their whole life cycle among the same sediment grains. This study is aimed at offering a first contribution to the assessment of DCF effects on freshwater invertebrate species living in the interstitial habitats of springs, rivers, lakes and groundwaters. The Crustacea Copepoda are one of the main components of the freshwater interstitial communities, with the primacy taken by the worm-like and small-sized harpacticoids. A sub-lethal concentration of 50 μg L DCF significantly affected six out of the eight behavior parameters of the burrower/interstitial crustacean harpacticoid Bryocamptus pygmaeus recorded by video tracking analysis. DCF exposure reduced swimming speed, swimming activity, exploration ability and thigmotaxis, and increased swimming path tortuosity. The biochemical approach revealed a reduced level of the mitochondrial superoxide dismutase 2 in individuals exposed to DCF. It could be explained by a decline in mitochondrial performance or by a reduced number of functional mitochondria. Since mitochondrial dysfunction may determine ATP reduction, it comes that less energy is produced for maintaining the cell functions of the DCF-exposed individuals. In addition, the increasing energy demand for the detoxification process further contributes to decrease the total energetic budget allocated for other physiological activities. These observations can explain the changes we have observed in the swimming behavior of the copepod B. pygmaeus.
双氯芬酸（DCF）是最广泛的药物化合物之一，由于其从点源和弥散源持续释放，作为一种假持久性污染物存在于淡水中，其在污水处理厂的去除并不完全。此外，DCF 在间隙生境中特别持久，对在同一沉积物颗粒中度过整个生命周期的物种具有潜在毒性。本研究旨在为评估 DCF 对生活在泉水、河流、湖泊和地下水间隙生境中的淡水无脊椎动物物种的影响提供第一个贡献。甲壳纲桡足类是淡水间隙群落的主要组成部分之一，其中以蠕虫状和小型桡足类为主。亚致死浓度为 50μg/L 的 DCF 显著影响了通过视频跟踪分析记录的穴居/间隙甲壳类桡足类 Bryocamptus pygmaeus 的八个行为参数中的六个。DCF 暴露降低了游泳速度、游泳活动、探索能力和触回避性，增加了游泳路径的曲折度。生化方法显示，暴露于 DCF 的个体中线粒体超氧化物歧化酶 2 的水平降低。这可以通过线粒体性能下降或功能线粒体数量减少来解释。由于线粒体功能障碍可能导致 ATP 减少，因此暴露于 DCF 的个体用于维持细胞功能的能量生成减少。此外，解毒过程中不断增加的能量需求进一步导致用于其他生理活动的总能量预算减少。这些观察结果可以解释我们在桡足类 B. pygmaeus 的游泳行为中观察到的变化。
