Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX, USA.
Institute of Applied Science, University of North Texas, 704 W Mulberry St, Denton, TX, USA.
Chemosphere. 2019 Jun;224:873-883. doi: 10.1016/j.chemosphere.2019.03.014. Epub 2019 Mar 4.
Freshwater bivalve populations are stressed by watershed development at the global scale. Though pharmaceuticals released from wastewater treatment plant effluent discharges are increasingly reported to bioaccumulate in fish, an understanding of bioaccumulation in bivalves is less defined. In the present study, we examined accumulation of 12 target pharmaceuticals in C. fluminea during a 42 day in situ study in Pecan Creek, an effluent dependent wadeable stream in north central Texas, USA. Caged clams were placed at increasing distances (5 m, 643 m, 1762 m) downstream from a municipal effluent discharge and then subsampled on study days 7, 14, 28 and 42. Acetaminophen, caffeine, carbamazepine, diltiazem, diphenhydramine, fluoxetine, norfluoxetine, sertraline, desmethylsertraline, and methylphenidate were identified in C. fluminea whole body tissue homogenates via isotope dilution liquid chromatography-tandem mass spectrometry. Tissue concentrations ranged from low μg/kg (methylphenidate) to 341 μg/kg (sertraline). By study day 7, rapid and apparent pseudo-steady state accumulation of study compounds was observed in clams; this observation continued throughout the 42 d study. Notably, elevated bioaccumulation factors (L/kg) for sertraline were observed between 3361 and 6845, which highlights the importance of developing predictive bioaccumulation models for ionizable contaminants with bivalves. Future research is also necessary to understand different routes of exposure and elimination kinetics for pharmaceutical accumulation in bivalves.
淡水双壳类种群受到全球流域开发的压力。尽管越来越多的报道称，从废水处理厂排放的废水中释放的药物会在鱼类中生物累积，但对双壳类生物累积的理解还不太明确。在本研究中，我们在 Pecan Creek 进行了 42 天的现场研究，研究了 12 种目标药物在 C. fluminea 中的积累情况， Pecan Creek 是美国德克萨斯州中北部一条依赖废水排放的可涉水溪流。在距离市政废水排放口下游 5 m、643 m 和 1762 m 的地方放置了笼养贻贝，然后在研究的第 7、14、28 和 42 天进行亚采样。通过同位素稀释液相色谱-串联质谱法，在 C. fluminea 整体组织匀浆中鉴定出对乙酰氨基酚、咖啡因、卡马西平、地尔硫卓、苯海拉明、氟西汀、去甲氟西汀、舍曲林、去甲舍曲林和哌甲酯。贻贝组织中的浓度范围从低μg/kg（哌甲酯）到 341μg/kg（舍曲林）。到研究的第 7 天，研究化合物在贻贝中的快速和明显的准稳态积累被观察到；这种观察持续了整个 42 天的研究。值得注意的是，在 3361 到 6845 之间观察到了舍曲林的生物积累因子（L/kg）升高，这突出了开发针对带电荷污染物的贝类预测性生物积累模型的重要性。未来的研究还需要了解药物在双壳类动物中的不同暴露途径和消除动力学。
