Micro- and nanoplastics are globally important environmental pollutants. Although research in this field is continuously improving, there are a number of uncertainties, inconsistencies and methodological challenges in the effect assessment of micro- and nanoparticles in freshwater systems. The current understanding of adverse effects is partly biased by the use of non-relevant particle types, unsuitable test setups and environmentally unrealistic dose metrics, which does not take into account realistic processes in particle uptake and consequent effects. Here we summarize the current state of the art by compiling the most recent research with the aim to highlight research gaps and further necessary steps towards more harmonized testing systems. In particular, ecotoxicological scenarios need to mirror environmentally realistic particle diversity and bioavailability. Harmonized test setups should include different uptake pathways, exposures and comparisons with natural reference particles. Effect assessments need to differentiate direct physical particle effects, such as lesions and toxicity caused by the polymer, from indirect effects, such as alterations of ambient environmental conditions by leaching, change of turbidity, food dilution and organisms’ behavior. Implementation of these suggestions can contribute to harmonization and more effective, evidence-based assessments of the ecotoxicological effects of micro- and nanoplastics.

中文翻译：

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对水生系统中微塑料和纳米塑料进行统一的生态毒理学效应评估


微塑料和纳米塑料是全球重要的环境污染物。尽管该领域的研究不断改进，但在淡水系统中微粒和纳米颗粒的效果评估中存在许多不确定性、不一致和方法挑战。目前对不利影响的理解部分是由于使用不相关的颗粒类型、不合适的测试设置和环境不切实际的剂量指标而产生的，这些指标没有考虑到颗粒吸收的现实过程和后续影响。在这里，我们通过汇编最新的研究来总结当前的技术水平，旨在突出研究差距和进一步采取必要的步骤，以实现更协调的测试系统。特别是，生态毒理学情景需要反映环境现实的颗粒多样性和生物利用度。协调的测试设置应包括不同的摄取途径、暴露以及与天然参考颗粒的比较。效果评估需要区分直接的物理颗粒效应（例如聚合物引起的病变和毒性）和间接影响（例如通过浸出改变周围环境条件、浊度变化、食物稀释和生物体的行为）。实施这些建议有助于对微塑料和纳米塑料的生态毒理学影响进行协调和更有效、循证评估。