生物质炭对酞酸酯类增塑剂污染土壤的原位修复及机理研究

Phthalic acid esters (PAEs) are the most common plasticizers. They are also classified as endocrine disrupting chemicals with a strong reproductive toxicity. Soils on protected vegetable cultivation sites are commonly contaminated with PAEs due to extensive use of plastic roofing materials and plastic mulch film. Concentration of PAEs in many contaminated soils is high and has well exceeded the maximum allowable values for soils in the United States. Phthalic acid esters in contaminated soils can be taken up by vegetable plants and consequently enter the human food chain. They may also leach to groundwater and contaminate drinking water sources. The proposed study aims to remediate the soils contaminated with PAEs on protected vegetable cultivation sites by applying biochar which can immobilize hydrophobic organic contaminants, such as PAEs in soils, through adsorption. Laboratory studies will be conducted to investigate the effects of soil properties, types of PAEs, types of biochars, application rates of biochar, and aging process of biochar, on the effectiveness of adsorption of PAEs by soils amended with biochars. The impacts of biochar application on the availability of PAEs for plant uptake will be carried out in a greenhouse experiment. The influence of biochar addition on the degradation of PAEs in soils will be determined with a laboratory incubation study. Leaching loss potential and the environmental fate of PAEs in contaminated soils will be assessed using column leaching and modeling techniques. These studies will help us better utilize biochar to immobilize PAEs in contaminated soils, minimize uptake of PAEs by vegetable crops, reduce the risk of leaching loss of PAEs to groundwater and ensure food safety. The proposed study will provide fundamental information for effective in situ remediation of soils contaminated with PAEs on protected vegetable cultivation sites thereby enhancing environmental quality and promoting safe food production.

酞酸酯（PAEs）属于环境内分泌干扰物，具有较强生殖毒性。目前我国设施菜地土壤中PAEs污染普遍存在，已远超美国PAEs土壤控制标准。PAEs可被蔬菜吸收进入食物链或淋溶进入地下水，严重威胁人类健康。本项目针对设施菜地的PAEs污染现状，采用对有机污染物吸附性极强的生物质炭作钝化剂，固定化封存PAEs以达到原位修复受污染土壤的目的。本研究将揭示土壤类型、PAEs理化性质、生物质炭老化过程等因子对生物质炭吸附钝化PAEs功能的影响及机理；解析生物质炭对PAEs植物有效性的作用；明确生物质炭对土壤中PAEs生物降解的影响；探索土壤中PAEs迁移规律。通过生物质炭合理高效的固定化封存土壤中PAEs，减少植物体内PAEs积累，缓解其淋溶风险，提高受污染土壤修复效率，保障食品安全。本项目将为设施菜地的PAEs污染原位修复提供理论支撑和科学依据，对提高我国生态环境质量和农产品质量安全具有重要指导意义。

酞酸酯（PAEs）属于环境内分泌干扰物，具有较强生殖毒性。目前我国设施菜地土壤中PAEs污染普遍存在，多地已远超PAEs土壤控制标准。PAEs可被蔬菜吸收进入食物链或淋溶进入地下水，威胁人类健康。本项目针对设施菜地的PAEs污染现状，同时结合我国农林废弃物资源丰富的现状，研究了揭示了利用生物质炭原位钝化土壤中PAEs生物活性的作用及其机理。试验选用竹炭、稻草炭作为典型生物质炭，以水溶性适中的邻苯二甲酸二乙酯（DEP）为代表性PAE，通过恒温批处理实验研究了生物质炭对土壤中DEP的吸附-解吸附能力的影响，结果显示，添加生物质炭可以加强土壤对DEP的吸附能力，并且与生物质炭的制备原料、温度、添加量、土壤类型密切相关；生物质炭老化后，对土壤中DEP的吸附能力下降，且干湿交替处理对DEP的吸附能力的减弱比恒湿老化处理更明显。在此基础上，以上海青为指示植物，以土壤中典型的DEHP为代表性PAE，通过盆栽实验解析了生物质炭对土壤中PAEs生物有效性的影响。结果表明，施用生物质炭能够增强土壤对DEHP的吸附固定能力，同时降低植物体内DEHP的累积，降低了污染物进入人体的风险；通过恒温恒湿培养实验，研究土壤有机质含量、生物质炭类型以及生物质炭和有机肥（风干羊粪）混施对土壤中DEHP动态降解的影响，结果表明，所有处理中DEHP的降解都符合一级反应动力学方程，且在低有机质土壤中添加猪炭和羊粪后，DEHP的降解速率加快。土柱淋溶试验结果表明，施加猪炭后土壤中DBP淋出率显著降低。.本项目通过一系列实验揭示了土壤类型、PAEs理化性质、生物质炭老化过程等因子对生物质炭吸附钝化PAEs功能的影响及其机理，为提高生物质炭原位修复污染土壤效率、避免污染物进入食物链、保障食品安全提供了新思路和理论基础。