School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215009, China.
School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Environ Pollut. 2018 Jul;238:1-9. doi: 10.1016/j.envpol.2018.03.001. Epub 2018 Mar 9.
While the presence of microplastics (MPs) in marine environments has been detected worldwide, the importance of MPs pollution in freshwater environments has also been emphasized in recent years. However, the body of knowledge regarding the biological effects of MPs on freshwater organisms is still much more limited than on marine organisms. The aim of the present study was to evaluate the accumulation and tissue distribution of MPs in the freshwater fish red tilapia (Oreochromis niloticus), as well as the biochemical effects of MPs on O. niloticus. During 14 days of exposure to 0.1 μm polystyrene-MPs at concentrations of 1, 10, and 100 μg L, the MPs concentrations in various tissues of O. niloticus generally increased over time following the order gut > gills > liver ≈ brain. Moreover, the acetylcholinesterase (AChE) activity in the fish brain was inhibited by MPs exposure, with a maximum inhibition rate of 37.7%, suggesting the potential neurotoxicity of MPs to freshwater fish. The activities of cytochrome P450 (CYP) enzymes [7-ethoxyresorufin O-deethylase (EROD) and 7-benzyloxy-4-trifluoromethyl-coumarin O-dibenzyloxylase (BFCOD)] in the fish liver exhibited clear temporal variabilities, with significant decreases followed by elevations compared to the control. The alterations of the EROD and BFCOD activities indicate the potential involvement of CYP enzymes for the metabolism of MPs. The activity of antioxidative enzyme superoxide dismutase (SOD) in the liver was significantly induced throughout the exposure period, while the malondialdehyde (MDA) content did not vary with MPs exposure, suggesting that the antioxidative enzymatic system in O. niloticus could prevent oxidative damage. These results highlight the ingestion and accumulation of MPs in different tissues of freshwater fish, which lead to perturbations in fish biological systems and should be considered in environmental risk assessment.
虽然已经在世界范围内检测到海洋环境中存在微塑料 (MPs)，但近年来，淡水环境中 MPs 污染的重要性也得到了强调。然而，与海洋生物相比，关于 MPs 对淡水生物的生物学影响的知识体系仍然要有限得多。本研究的目的是评估淡水鱼类罗非鱼 (Oreochromis niloticus) 体内 MPs 的积累和组织分布，以及 MPs 对 O. niloticus 的生化影响。在 14 天暴露于浓度为 1、10 和 100μg/L 的 0.1μm 聚苯乙烯 MPs 期间，随着时间的推移，O. niloticus 体内各种组织中的 MPs 浓度普遍增加，其顺序为肠道＞鳃＞肝脏≈大脑。此外，暴露于 MPs 会抑制鱼类大脑中的乙酰胆碱酯酶 (AChE) 活性，最大抑制率为 37.7%，这表明 MPs 对淡水鱼类可能具有神经毒性。鱼肝脏中细胞色素 P450 (CYP) 酶 [7-乙氧基香豆素 O-脱乙基酶 (EROD) 和 7-苄氧基-4-三氟甲基香豆素 O-二苄氧基酶 (BFCOD)] 的活性表现出明显的时间变异性，与对照组相比，活性显著降低后又升高。EROD 和 BFCOD 活性的改变表明 CYP 酶可能参与了 MPs 的代谢。暴露期间，肝脏中超氧化物歧化酶 (SOD) 的抗氧化酶活性显著诱导，而丙二醛 (MDA) 含量没有随 MPs 暴露而变化，这表明 O. niloticus 的抗氧化酶系统可以防止氧化损伤。这些结果突出了 MPs 在淡水鱼不同组织中的摄入和积累，这导致了鱼类生物系统的紊乱，应在环境风险评估中加以考虑。
