珠江与南海水域塑料微粒污染及其对内分沁干扰污染物环境行为和归宿的影响

Plastics are widely used in daily-life and industrial products. As a result, plastic pellets and particles have been omnipresent in the environment, causing a global concern. Microplastics (MPs) are persistent and can be transported long distance, with current and gyre, even to remote pole areas. MPs are easily intaken by several animals due to the particle sizes in the range of food of these animals, threatening health of the ecological system. Most importantly, MPs may act as sources, sink, and carrier of toxic chemicals in the environment, releasing, transporting these chemicals, and enhancing their bioaccumulation and biotransfer. Therefore, MPs have been categorized into emerging priority pollutants. In this project, spatial and temporal distribution of MPs will be investigated in depth in the Pearl River and its tributaries, the Pearl River Estuary, and the South China Sea. Sources, environmental behavior, and bioaccumulation of the MPs will be illustrated. Contributions of the MPs to distribution, behavior and fate of endocrine disrupting chemicals (EDCs), such as bisphenol A and its analogs, tetrabromobisphenol A and its analogs, alkylphenols and their polyethoxy ethers, bensotriazole UV stabilizers in the aquatic environment will be studied. Impact of the MPs on bioaccumulation and biotransfer of the EDCs will also be discussed to reveal the ecological hazard of the MPs contamination, especially to wild life organisms. The outcome of this project will be helpful to take appropriate precautions and promote technology development in order to reduce significantly plastic contamination and associated toxic chemical contamination in the environment.

塑料渗透现代生活，塑料碎屑/废物亦随之遍及环境，成为全球性环境隐患。塑料微粒（MPs）在环境中不易降解，可随水/洋流远距离迁移；可能在生物体中累积，威胁生态系统的健康；MPs还可能是环境中内分泌干扰污染物（EDCs）、持久性有机污染物等毒害化学品的源、汇和载体。为此，MPs已成为水环境中最重要的污染物之一。本项目拟以珠江流域、珠江河口和南海为基地，系统研究水体中MPs的时空分布、形态、化学组成和演变趋势，解析其来源、迁移、环境行为和归宿；研究MPs在生物中的累积，初步探索其沿食物链的传播；揭示环境中MPs与增塑剂、阻燃剂、表面活性剂、光稳定剂等典型EDCs之间的关系，诠释MPs对环境中EDCs的贡献及其对EDCs环境行为和归宿的影响，探究MPs在EDCs生物富集和沿食物链传播中的作用，揭示MPs污染对环境和生态可能产生的风险。研究成果将有利于从根本上减少塑料污染和与之相关的化学品污染。

本项目系统研究了珠江流域水、沉积物、沉积物柱芯以及生物中塑料微粒（MPs）的分布、表征了MPs的聚酯化学组成、颗粒形态、粒度等物理特征，季节变化以及空间演变、揭示了MPs的环境行为和影响其在环境及和生物中累积的因素。珠江流域MPs分布广泛，河水中浓度为0.008-0.146 mg/L，丰度为0.129-3.138 粒/L，河流沉积物中MPs的浓度为0.174±0.115 mg/g干重, 丰度为685± 343粒/Kg干重。河水和沉积物中<0.1 mm的颗粒数量最多，然而1-5mm的MPs重量占比最大。MPs以片状为主，依次为碎屑状、线状、纤维状，偶见泡沫状和球状。珠江河口表层沉积物中MPs的丰度为258 ± 133 items/Kg 干重，浓度为0.014 ± 0.014 mg/g，以纤维状为主, 次为碎屑状，有少量球状和薄膜状，其中球状MPs占比明显高于河水和河流沉积物。MPs在珠江河口沉积物柱芯中的丰度表现出自上往下降低的趋势，表明随着塑料产量和使用量的增加，沉积物中塑料的积累也逐渐增多；然而，<0.45mm的MPs比重则随深度增加而增大，到42 cm 深度时达100%。表明塑料颗粒可在沉积物中持久存在，细颗粒塑料可能存在往下渗透。珠江流域半数以上可食用野生淡水鱼胃肠道中含塑料碎屑，丰度为7.0 ± 23.8 粒/条，最高达247粒/条。共检测到21种聚酯，其中河水、河流沉积物以及河口沉积物中的MPs均以碎片状和薄膜状聚丙烯（PP）、聚丙烯（PE）、PP-PE聚合体为主，表明主要来源于废弃的塑料制品。此外，洗涤污水也是珠江流域水体中MPs的重要来源之一。野生鱼中的塑料则主要是透明/白色的PET纤维和PE、PE-PP碎片。野生淡水鱼中塑料碎屑在丰度、形状以及化学组成等方面表现出一定的种间差异，底栖的杂食性鱼类肠道中的塑料丰度相对较高，食物组成可能是影响鱼类肠道中塑料的重要因素。珠江流域塑料碎屑的丰度与人口密度表现出明显的正相关，表明人类活动是珠江流域塑料污染的最主要来源。珠江流域水生生物中与塑料相关的内分泌干扰污染物（EDCs）分布广泛，如增塑剂BPA和紫外线吸收剂等塑料添加剂。有些EDCs表现出明显的生物富集潜力和代际传递潜力，威胁生态健康。