农田土壤微塑料对典型有机污染物生物有效性的影响机制

Long-term, large-area application of plastic film covering, wastewater reuse irrigation, and sludge recycling technologies in agricultural production accumulate large amounts of microplastics in the soil. Microplastics have the characteristics of small particle size, large specific surface area and strong hydrophobicity which could interact with organic pollutants in the environment and act as carriers of organic pollutants to accelerate the migration and transformation of pollutants. Nowadays, studies on the effects of microplastics on the migration and transformation of coexisting organic pollutants in soil have rarely been reported. This project aims at the pioneering scientific issues in the research for migration and bioavailability of soil organic pollutants. In particular, this study intended to develop a new method for quantitative analysis of microplastics in the soil. The project will also study the influence and mechanism of microplastics on the bioavailability of typical organic environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the soil. The mechanisms of the accumulation of organic pollutants affected by microplastics in economic crops such as corn, spinach, rice and pumpkin would be explored. The result of this project is expected to provide scientific evidence for the establishment of environmental quality standards for soil and the safety protocols of agricultural production.

农业生产中长时间、大面积塑料薄膜覆盖、污水回用灌溉和污泥回用等技术会在土壤中累积大量的微塑料。微塑料具有粒径小、比表面积大、疏水性强的特性，能与环境中的有机污染物发生相互作用，作为有机污染物的载体加速污染物的迁移与转化。迄今，微塑料对土壤中共存的有机污染物迁移转化影响研究鲜见报道。本项目旨在围绕土壤有机污染物迁移积累及生物有效性研究领域的前沿科学问题，以微塑料对土壤中典型有机污染物生物有效性的影响及机制为研究核心，构建土壤微塑料定量检测新方法，阐明微塑料对土壤中多环芳烃(PAHs)、有机氯农药(OCPs)等典型有机环境污染物赋存形态的影响。探明微塑料影响玉米、菠菜、水稻、南瓜等经济作物吸收累积有机污染物的机制，为保障农产品安全和科学制定土壤环境质量标准提供科学依据。

农业生产中长时间、大面积的应用薄膜覆盖、污水回用灌溉和污泥回用技术会在土壤中累积大量微塑料。探究土壤-植物体系中微塑料对植物吸收积累有机污染物，植物毒性和影响机制是科学评估土壤及作物微塑料污染风险的关键，也是保障农作物品质与安全的重要基础。本研究构建了高效的微塑料定量分析方法；阐明微塑料对土壤典型有机污染物赋存形态影响及生物有效性的调控机理；揭示微塑料影响作物吸收累积有机污染物的机制，探究了土壤-植物体系中微塑料对植物毒性和影响机制。主要成果如下：.1）建立了一种半自动化高通量的微塑料检测方法，解决了微塑料难以准确定量分析的难题，实现了从100nm到20μm的大跨度微塑料检测，构建了流式细胞仪-激光红外成像系统联用的微塑料定量和定性方法。成功应用于市政污泥样品、农田土壤样品、地表水和沉积物样品中微塑料的检测。.2）采用了同位素标记和超声连续提取法联用，对共存微塑料时土壤有机污染物赋存形态进行分析。从土壤有机污染物赋存形态的角度揭示了共存微塑料对有机污染物迁移转化的影响规律。.3）发现了微塑料表面带负电荷会促进玉米、菠菜、水稻、南瓜吸收累积有机污染物，阐明了微塑料对作物的毒性效应主要来源于ROS所造成的氧化损伤，揭示微塑料暴露会影响植物的代谢物积累和能量消耗，扰乱TCA循环并导致作物品质产生差异。.