微塑料影响下设施菜地土壤中的典型兽用抗生素运移机制研究

Returning livestock and poultry manure to the field is an important action to promote the development of greenhouse vegetable industry. However, this move will allow veterinary antibiotics remaining in manure to enter vegetable soils, and then endangering vegetable safety and human health. Thus, revealing the migration of veterinary antibiotics in vegetable soils is significative to evaluate the ecological risks of these pollutants. Microplastics are a group of organic solid wastes, widely distributed in soil environments. They may influence the migration of antibiotics in soils via acting as sorbents and/or carriers. However, the study addressing this topic is too scarce. In this project, greenhouse vegetable soils will be selected as the study area due to the seriously combined pollution of veterinary antibiotics and microplastics. The sorption/desorption, leaching, and accumulation of the target antibiotics in the soil-radish system under different microplastic pollution conditions will be studied using batch experiments, column experiments, and pot experiments. Influencing factors will be determined according to the correlation analysis between the migration laws of antibiotics and the content and properties of microplastics. Based on the analysis of competitive adsorption between antibiotics and microplastics, analysis of the species of antibiotics in the leachate, and micro-characterization techniques, the influence mechanisms of competitive adsorption and co-transport will be studied. Meanwhile, combining the effects of microplastics on soil properties and radish growth, the indirect effects of microplastics on antibiotic migration will be explored. This project will provide basic information for the pollution control and risk assessment of co-existing pollutants in greenhouse vegetable fields.

畜禽粪肥还田是推进设施蔬菜产业发展的重要环节，但该举措将促使粪肥中残留的兽用抗生素进入菜地，危害蔬菜安全和人体健康。揭示兽用抗生素在菜地中的运移对于评估其环境风险具有重要意义。作为广泛存在于土壤中的有机固体，微塑料可能通过吸附、载体等作用影响抗生素的运移行为。但目前关于此课题的研究十分匮乏，微塑料对土壤抗生素运移的影响机制尚不明晰。本项目以兽用抗生素和微塑料复合污染严重的设施菜地为研究区，结合批实验、柱实验和盆栽试验，研究不同微塑料污染条件下抗生素在土壤—萝卜系统中的吸附/解吸、淋溶和植物吸收过程，揭示微塑料含量和属性对抗生素运移行为的影响。基于抗生素与微塑料的竞争吸附分析、淋出液中抗生素赋存形态分析及微观表征技术，探究竞争吸附、协同迁移等直接影响机制；根据微塑料对土壤水力性质和萝卜生长的影响，探讨微塑料对抗生素运移的间接影响机制；为设施菜地抗生素与微塑料复合污染的风险评估和控制提供依据。