淡水环境中微塑料与重金属的“木马效应”研究进展

微塑料(尺寸<5 mm的塑料)作为全球备受关注的新兴污染物，广泛存在于淡水环境中.微塑料易迁移，难降解，且比表面积大，对重金属等多种污染物有富集作用，大大增加了其对环境和生态的潜在危害.因此，本文首先定义微塑料在淡水环境中携带重金属并共同迁移的特殊环境行为为“木马效应”.随后，从淡水环境中微塑料的来源与分布、微塑料对重金属的富集作用、微塑料与重金属木马效应对其共同迁移行为的影响以及微塑料和重金属木马效应的生物影响这4个方面对淡水环境中微塑料与重金属的木马效应及其作用机制进行了总结和阐述.结果表明，作为面源广的污染物，微塑料广泛存在于淡水环境中；淡水环境中微塑料对重金属存在吸附行为，不同环境下对单一重金属吸附程度不同，主要受微塑料、金属和环境等因素共同影响，在多种重金属离子存在时会有竞争吸附；微塑料与重金属的木马效应会影响其共迁移行为；淡水环境中微塑料与重金属的木马效应，往往加剧了其对水生生物的毒性.通过全面了解淡水环境中微塑料与重金属的木马效应及其作用机制，可有效降低微塑料与重金属在淡水环境中的生态风险和对人类健康的影响提供借鉴.

Research Progress on Trojan-horse Effect of Microplastics and Heavy Metals in Freshwater Environment

As an emerging pollutant of global concern, microplastics (plastics with size<5 mm) and heavy metals are widely found in freshwater environments. Microplastics migrate easily, are difficult to degrade, and have large specific surface areas. They can enrich a variety of pollutants such as heavy metals and greatly increase their potential harm to the environment and ecology. Firstly, the special environmental behavior of microplastics carrying heavy metals and migrating together in freshwater environments was defined as the "Trojan-horse effect." Then, the Trojan-horse effect and its mechanism of microplastics and heavy metals in the freshwater environment were summarized and expounded from four aspects:the source and distribution of microplastics in the freshwater environment, the enrichment effect of microplastics on heavy metals, the impact of microplastics and the heavy metal Trojan-horse effect on its migration behavior, and the biological impact of microplastics and the heavy metal Trojan-horse effect. The results showed that, as a wide range of non-point source pollutants, microplastics widely existed in freshwater environments. In freshwater environments, the adsorption degree of single metals was different in different environments. It was mainly affected by microplastics, metals, and environmental factors. There was competitive adsorption in the presence of multiple metal ions. The Trojan-horse effect of microplastics and heavy metals could also affect their co-transport behavior. The Trojan-horse effect of microplastics and heavy metals in the freshwater environment frequently exacerbated their toxicity to aquatic organisms. This study provides references for comprehensively understanding the Trojan-horse effect and its mechanism in microplastics and heavy metals in the freshwater environment, which could effectively reduce the ecological risk and impact on human health of microplastics and heavy metals in the freshwater environment.