土壤环境中典型抗生素污染的联合毒性机理及生态风险

Antibiotics can be introduced into the soil system by many different pathways as a result of their widespread production and consumption. Antibiotics persisting in soil can have toxic effects on soil flora and fauna and can pose a danger to the ecosystem and to human health through biological magnification. It is therefore urgent and necessary to characterize the ecological risks of antibiotic pollution in soil, which is the hot issue of environment research. In our study, the antibiotics tetracycline (TC), chlorotetracycline (CTC), and sulfadiazine (SD) are selected as the research object, which have a relatively high rate of detection and residual concentration in soil. Laboratory experimental methods (e.g., pot culture experiments, rhizosphere experiments, and microcosmic toxicity tests) and modern analytical technology (e.g., HPLC, UV-VIS, DDRT-PCR, Biolog, and PCR-DGGE) are employed to study the joint toxicity of combinations of antibiotics to soil flora and fauna. The toxicity mechanism of combinations of antibiotics (TC-SD，CTC-SD，TC-CTC) are investigated with respect to soil microbial community structure and diversity, animal and plant development and detoxification enzyme activity, gene expression in animals, and root tip cells and root exudates of plant. Based on our toxicity data, an ecological risk assessment model of antibiotic pollution in soil is constructed using fuzzy logic. The findings of this project will supplement basic eco-toxicological data on emerging pollutants in soil, promote the development of pollution ecology, and provide an important scientific basis and theoretical guidance for diagnosis of soil pollution, contaminated soil remediation, and environmental risk management.

抗生素巨大的使用量导致其可以通过多种途径进入土壤环境，对土壤微生物和动植物产生毒性效应，并通过生物链传递，给生态系统和人体健康带来危害。如何有效地对土壤抗生素污染危害进行早期生态风险预警是环境领域的研究热点和难点。本项目以土壤中检出率和检出浓度较高的四环素（TC）、金霉素（CTC）和磺胺嘧啶（SD）为研究对象，通过盆栽/根际实验、微宇宙实验等室内模拟实验，利用HPLC、UV-VIS、DDRT-PCR、Biolog、PCR-DGGE等技术，重点研究抗生素复合污染（TC-SD，CTC-SD，TC-CTC）对土壤微生物和动植物的联合毒性机理，包括土壤微生物群落结构与功能多样性、动植物生长发育及基因表达差异、植物根系分泌物等；基于此，建立抗生素污染土壤的生态风险评估模型。研究成果可以补充和完善土壤新型污染物的生态毒理学基础数据，推动土壤污染生态学发展，为土壤污染诊断评价和风险管理提供理论指导。

抗生素巨大的使用量导致其可以通过多种途径进入土壤环境，对土壤微生物和动植物产生毒性效应，并通过生物链传递，给生态系统和人体健康带来危害。如何有效地对土壤抗生素污染危害进行早期生态风险预警是环境领域的研究热点和难点。本项目以土壤中检出率和检出浓度较高的四环素（TC）、金霉素（CTC）和磺胺嘧啶（SD）为研究对象，通过盆栽/根际实验、微宇宙实验等室内模拟实验，利用HPLC、UV-VIS、DDRT-PCR、Biolog等技术，重点研究了抗生素单一及二元复合污染对土壤微生物和动植物的毒性效应及机理。结果表明，抗生素单一及二元复合污染对土壤呼吸强度、土壤酶活性以及土壤微生物群落结构及功能多样性均具有显著影响；抗生素单一及二元复合污染胁迫下赤子爱胜蚓的生长发育受到抑制，体内抗氧化防御系统遭到破坏、基因表达呈现差异性；抗生素单一及二元复合污染胁迫下小白菜种子萌发及幼苗发育均受到影响，体内可溶性蛋白含量发生变化，抗氧化防御系统损伤，植物根际土壤微生物群落结构发生显著变化。与单一抗生素污染相比，二元复合污染对受试生物的联合毒性更为显著，但并不是简单的加合作用。此外，土壤类型、抗生素理化性质等因素均会影响抗生素对受试生物的毒性效应。本项目研究成果可以补充和完善土壤新型污染物的生态毒理学基础数据，推动新型污染物环境阈值研究工作的发展，为土壤污染诊断评价和风险管理提供理论指导。