水环境中微塑料的光老化过程及影响因素研究进展  

Progress on the photo aging mechanism of microplastics and related impact factors in water environment

作　　者：吴小伟 黄何欣悦 石妍琦 刘鹏[2] 王晗钰 高士祥[1] Xiaowei Wu;Hexinyue Huang;Yanqi Shi;Peng Liu;Hanyu Wang;Shixiang Gao(State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China;College of Resources and Environment,Northwest A&F University,Xianyang 712100,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023 [2]西北农林科技大学资源环境学院,咸阳712100

出　　处：《科学通报》2021年第36期4619-4632,共14页Chinese Science Bulletin

基　　金：国家自然科学基金(21876076)资助。

摘　　要：微塑料作为一种新兴污染物,由于粒径较小且性质稳定,能够作为水环境中污染物的载体,并对水生生物具有毒性危害.排放到水环境中的微塑料颗粒经过光照和机械破碎等风化过程后,其表面形态和理化性质会发生改变,并分解破碎成为粒径更小的微米级或纳米级塑料颗粒.本文系统地综述了微塑料在水环境中的光老化和破碎过程.这是由于光老化当前被认为是影响微塑料风化破碎最主要的途径,研究微塑料的光老化机制对于评价水环境中微塑料的形成过程及潜在生态风险有重要意义.微塑料在水环境中的光老化过程本质上是自由基引发的链式反应过程,通过改变微塑料表面基团的化学结构和组成影响其极性、亲疏水性和毒性,并通过影响高分子链的排列改变微塑料的机械性能,诱导微塑料进一步破碎形成粒径更小的塑料颗粒,这也是水环境中形成微塑料的重要途径.此外,微塑料在自然水体中的光老化过程会受到聚合物种类、塑料添加剂、生物膜、卤素离子和天然有机质等具有光化学活性物质的影响.通过实验室模拟微塑料在自然水环境中的长期老化行为过程中,应更多考虑复合添加剂和水质条件的共同影响.期望本综述能为全面和系统地评估老化微塑料的环境行为、毒理学效应及水环境生态风险提供理论支持.As an emerging pollutant, microplastics(MPs, plastic particles with size < 5 mm) pollution in water has acquired extensive attention in recent years due to their small particle size and stable properties, which can act as a carrier for pollutants in water environment and have toxic hazards to aquatic organisms. After entering into water environment, MPs are readily undergone varied types of weathering processes(i.e., hydrolysis, photo oxidation, mechanical abrasion, and biodegradation), leading to shifted surface morphology(i.e., surface roughness, specific surface area, and size) and physicochemical properties(i.e., melting temperature, surface charge, molecular weight, crystallinity, and hydrophobicity).Among different weathering processes of MPs in water, sunlight induced photo aging process has been considered as primary contributor, which will further impact the MPs behaviors, such as aggregation and deposition in water column,adsorption to organic and inorganic pollutants, leaching of additives, as well as toxicity to organisms in water. From the perspective of MPs aging mechanism, photo aging process of MPs in water environment is a free radical associated chain reaction process and readily to be affected by polymer types, plastic additives, halogen ions, and natural organic matters.These components are generally photochemical activated and prone to involved in the direct or free radical associated indirect photo aging process processed. However, limited information has referred the impact of plastic additives and water constitutes on the long term weathering process for MPs in water, which will pose a great difference between laboratoryaccelerated weathering and long-term natural weathering. Studying the photo aging mechanism of MPs in water environment is of great significance for evaluating their formation process and potential ecological risks. Based on the above considerations, we systematically reviewed the photo aging and fragmentation processes of MPs in water environment. The content of this work

关 键 词：微塑料 老化 天然有机质 塑料添加剂 卤素离子 

分 类 号：X52[环境科学与工程—环境工程]