微塑料与有机污染物的相互作用研究进展

微塑料(粒径小于5 mm的塑料)作为海洋中一种新型的污染物正受到越来越多的关注。微塑料在全球多个海域均有检出,根据其来源分为原生微塑料和次生微塑料。原生微塑料由人工直接制造所得,常见于日常生活用品中;次生微塑料由大块塑料制品长期风化、磨损和光解形成。塑料自身含有多种有机添加剂,不断向环境中释放,污染海洋环境;微塑料表面还可吸附有机污染物,此吸附作用受两者的物理化学性质和环境条件影响,吸附污染物后的微塑料生物毒性增强。另外,聚合物复合光催化材料可加快有机污染物如染料的光降解反应速率,因而微塑料可能会促进有机污染物的光解。针对目前微塑料对有机物光降解的贡献、机理鲜见研究的问题,未来应加强以下3方面的研究:(1)微塑料对不同有机污染物光降解是否存在影响?(2)微塑料类型、尺寸以及反应条件对有机污染物光降解如何影响?(3)微塑料对有机污染物光降解影响的内在机制是什么?

Interactions between Microplastics and Organic Pollutants: Current Status and Knowledge Gaps

As a new emerging of contaminant in ocean, microplastics (particles < 5 mm) are gaining more and more attention. Microplastics are detected in the oceans around the world. Microplastics can occur in the environment either as primary or secondary microplastics. Primary microplastics are derived from a number of artificially manufactured products such as industrial abrasives and cosmetics products. Secondary microplastics are formed from long-term weathering, abrasion and photodegradation of large pieces of plastic products. Plastic itself contains a variety of organic additives, which can release into the environment continuously and pollute the marine environment. The surface of microplastics can adsorb organic pollutants that existed in environment, which is influenced by the physical and chemical properties of microplastics and pollutants, as well as the environmental conditions. The biological toxicity of microplastics can significantly increased after organic pollutants sorbed on them. Studies showed that polymeric photocatalysts could accelerate photodegradation rate of organic pollutants like dyes, thus it is reasonable to hypothesize that microplastics may stimulate photodegradation of contaminants. However, the influence and mechanism of microplastics on photodegradation of organic pollutants is not well understood. Therefore, more studies in future should be focused on the following questions: (1) can microplastics affect photodegradation of organic pollutants? (2) how can the microplastic type, size and environmental conditions affect the photodegradation of organic pollutants? (3) what are the underlying mechanisms responsible for photodegradation of organic pollutants induced by microplastics?