纳塑料对淡水生物的效应概述

Effects of Nanoplastics on Freshwater Organisms:A Review

塑料污染日益严重,已成为当今世界最受关注的环境问题之一。环境中的塑料碎片会进一步破碎降解形成粒径小于1μm的塑料颗粒,即纳塑料(nanoplastics)。当前,有关纳塑料的行为效应研究主要集中于海洋生态系统,而对淡水生态系统这一塑料污染重灾区研究较少。有鉴于此,本文梳理了纳塑料对淡水生态系统中生物的毒性效应及主要致毒机制的相关文献,并按照营养级由低到高的顺序(微藻、浮游动物、鱼类)对其生物效应进行概述。已有研究表明,纳塑料能够通过抑制光合作用、促进细胞异质团聚、破坏细胞结构、诱导氧化胁迫等多种途径影响微藻细胞生长。纳塑料还能使浮游动物和鱼类行为活动异常,破坏其能量平衡,引发氧化胁迫与基因毒性,进一步抑制它们的生长发育与繁殖。然而,现有研究依然存在纳塑料及受试生物类别单一,试验纳塑料浓度与真实环境浓度脱节;试验介质多为人工培养基,组成简单,无法准确反映自然体系的复杂性;且试验设计未充分考虑纳塑料的老化、与天然有机质或其他污染物的相互作用等问题。因此,未来的研究应聚焦于环境浓度相对较高的纳塑料和丰度高、敏感性强的生物种群,并设计更贴合真实环境的试验条件,以更好地评估纳塑料的生物效应,为淡水生态系统中纳塑料的污染防治、相关标准的制定提供理论支撑。

Plastic pollution is increasingly serious and has emerged as one of the most critical environmental p roblems in the world today.Plastic debris in the environment further degrades,forming particles smaller than 1μm,known as nanoplastics.Currently,studies on the behavioral effects of nanoplastics are mainly focused on marine ecosystems,but less on freshwater ecosystems which are the hardest hit by plastic pollution.In view of this,this paper summarizes the literature on the toxic effects of nanoplastics on organisms in freshwater ecosystems and the main mechanisms of toxicity,providing an overview of their biological effects according to the order of trophic level(microalgae,zooplankton,fish)from low to high.Studies have shown that nanoplastics can affect microalgal cell growth through various pathways,such as the inhibition of photosynthesis,promotion of hetero-aggregation,disruption of cellular structure,and induction of oxidative stress.Nanoplastics can also cause abnormal behavior in zooplankton and fish,disrupting their energy balance,inducing oxidative stress and genotoxicity,and further inhibiting their growth,development and reproduction.However,existing studies still lack diversity in nanoplastics c ategories and test organisms.The concentration of experimental nanoplastics is not in line with the real environmental conditions.Moreover,the experimental media are mostly artificial,with a simple composition that cannot accurately reflect the complexity of the natural system.Furthermore,the experimental design does not sufficiently take into account the aging of nanoplastics,the interaction with the natural organic matter or other pollutants,and so on.Therefore,future research should focus on nanoplastics existing in environments with relatively notable c oncentrations,as well as biological populations with high abundance and sensitivity.Designing experimental c onditions that are more closely related to the real environment so as to better assess the biological effects of n anoplastics.These efforts will provide theoretical support for the prevention and control of nanoplastics in f reshwater ecosystems as well as the formulation of relevant standards.