微塑料对土壤中抗生素生物有效性与生态毒性的影响机制

Intensive agricultural production has resulted in formation of microplastics and antibiotics in farmland soils at the same time, which has adversely affected the safety of agricultural products and increased health risks for humans through dietary ingestion. Microplastics can act as containers for contaminants and may play an important role in geochemical process of the contaminants. Research on effects and mechanisms of antibiotics mediated by microplastics mainly focused on adsorption process, biological magnification, and eco-toxicology effect in water system, while effects and mechanisms of environmental behaviors of the antibiotics mediated by microplastic in soil remain unclear. Based on the previous research, this study aims to verify influence of microplastics on environmental behaviors of antibiotics in soil. The main focus of this study is on effects of microplastics with various types, ageing process and environmental factors on the adsorption of antibiotics in soils. The effects of plastics on bioaccumulation of antibiotics in plants and soil animals will also be studied. The effects of interaction process between microplastics and antibiotics on physiological and biochemical of plant, microbial community structure and animal ecotoxicity will be determined. In addition, the relationship between bioaccumulation and interaction process can be revealed. The mechanism of influence of bioavailability and ecotoxicity of antibiotics by microplastics can be explained through a multi-dimensional system of soil, plant and animal. This proposed study will provide scientific basis for assessing the environmental risks of microplastic and antibiotics. This is of great significance for the safe qualities of agricultural products in soil of combined pollution by microplastics and organic pollutants in China.

农业集约化生产易造成微塑料和抗生素同时普遍存在于农田土壤中，严重危害农产品安全和人体健康。微塑料可吸附污染物，对污染物的地球化学过程起着重要作用，研究主要集中于水体中传统型疏水性有机污染物的吸附过程、生物富集及生态毒理等，有关土壤中微塑料对抗生素环境行为的影响及机制的研究鲜见报道。本项目在前期研究基础上，旨在探明微塑料对土壤中抗生素环境行为的影响及机制，重点研究微塑料类型、老化过程及其他环境因子对微塑料吸附土壤中抗生素的影响机制；探讨微塑料对植物和土壤动物生物富集抗生素的影响；研究微塑料与抗生素相互作用过程对植物生理生化、微生物群落结构及土壤动物生态毒性的影响及与生物富集之间的关系，从土壤-植物-动物多角度揭示微塑料对土壤中抗生素生物有效性与生态毒性的影响机制。该项目为评估微塑料和抗生素环境风险提供科学依据，对于微塑料与有机污染物复合污染的土壤生产安全农产品具有重要的科学意义和现实意义。

近年来，微塑料污染问题被列入全球第二大环境问题，成为环境科学和生态领域研究的热点问题，在海洋环境中受到普遍关注。相比海洋环境，陆地环境特别是农田土壤中微塑料污染特征和生态风险的研究尚处于起步阶段，有研究估算农田土壤中微塑料丰度远比海洋环境中大。抗生素在农田土壤中普遍存在，容易与微塑料在农田土壤中形成复合污染。进入到环境中的抗生素会与微塑料发生一定的界面化学作用，这种界面作用会对抗生素的迁移产生重要的影响。因此，本项目在前期研究基础上，旨在探明微塑料对土壤中抗生素环境行为的影响及机制，研究微塑料与抗生素相互作用过程对植物生理生化、微生物群落结构及土壤动物生态毒性的影响及与生物富集之间的关系，从土壤-植物-动物多角度揭示微塑料对土壤中抗生素生物有效性与生态毒性的影响机制。.研究结果表明：不同粒径、类型微塑料对抗生素的吸附行为存在显著差异，特别是小粒径的微塑料对疏水性的磺胺类的吸附作用更为显著。3种微塑料普遍降低了植物对抗生素的吸收累积作用，其中高密度的聚乙烯对抗生素生物有效性的影响显著高于低密度的聚乙烯。微塑料与抗生素复合污染对生菜的毒害效应显著高于单一微塑料/抗生素的作用，复合污染均显著降低了生菜的发芽率、鲜重和光合作用系统。微塑料和抗生素加入农田土壤后均显著改变土壤的pH、含水率、C:N比等，且粒径大小对土壤pH值和C:N比影响较大，但对土壤含水率影响不显著；复合污染均降低了土壤中微生物的丰富度和多样性，且蚯蚓显著促进了复合污染对土壤微塑料丰富度和多样性的降低作用。相关性分析显示，低密度聚乙烯与环丙沙星复合污染土壤微生物群落结构和土壤理化性质的相关性与微塑料的粒径密切相关。.该项目的研究内容全部完成，已发表2篇SCI论文，2篇中文核心论文，授权3项发明专利，研究结果为评估微塑料和抗生素环境风险提供科学依据，对于微塑料与有机污染物复合污染的土壤生产安全农产品具有重要的科学意义和现实意义。.