[Occurrence Characteristics of Microplastics in Aquatic Environments and Their Environmental Ecological Risk...

Microplastics (MPs) are persistent pollutants that are resistant to degradation and can persist in the environment for extended periods, exerting negative impacts on ecosystems. Through Meta-analysis, the distribution of MPs in domestic and international water bodies was comprehensively analyzed based on representative data extracted from the literature. This data included occurrence characteristics such as abundance, shape, size, color, and composition of MPs in marine, river, and lake water bodies. The results indicated that marine, riverine, and lacustrine systems across the globe are subjected to varying degrees of MP pollution. The predominant components identified were polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, and polystyrene, with black, white, and transparent colors being the most common. The particle sizes of MPs were largely distributed within the range of 0-1 mm. The Tukey's test revealed significant differences in MP abundance between marine and freshwater systems (P < 0.05), while no significant differences were observed between riverine and lacustrine systems. MPs were concentrated in areas of intense human activity, with primary sources including fishing activities, plastic waste degradation, laundry, and personal care products. Spatial and temporal variations in MP distribution were attributed to factors such as monsoon currents, geographic location, and water flow direction. MPs were also found to be ingested and accumulated by aquatic organisms, leading to oxidative stress, neurotoxicity, endocrine disruption, and immune damage, which negatively affected metabolism and reproduction. A total of 38 studies on the ecological risk assessment of MPs in aquatic environments were synthesized to evaluate the applicability, advantages, and limitations of current assessment methods. The findings indicated that the ecological risks of MPs in aquatic systems were predominantly classified as levels Ⅰ-Ⅲ, with MP abundance and polymer toxicity being the primary factors influencing overall risk levels. Finally, future research directions were proposed for studying the occurrence characteristics and ecological risk assessment of MPs in aquatic environments.