酸化加剧对红壤中有机磷农药生态毒性的影响及其毒理学机制-以赤子爱胜蚓为例

The acceleration of soil acidification is the typical characteristic of red soil and has become a typical impact factors of agricultural production. In the process of agricultural production, pesticides are often used by people and therefore soil ecological toxic effects of common pesticides have been investigated by former works, due to the low biodegradation and the high accumulation in organisms. However, it is still unclear what is the effect of soil acidification upon the soil ecological toxicity of pesticides and how the mechanism of ecological toxicity variation, although answering these questions is the key to accurately evaluate the ecological toxicity of pesticides in jiangxi province, due to the soil continual acidification. Consequently, to answer these questions, organophosphorus pesticides, widely used pesticides in China, are used as pollutants and a widely accepted model organism, Eisenia foetida, is chose in this project. Firstly, the toxic effects of selected organophosphorus pesticides upon E.foetida will be determined at individual, biochemical and cellular level by using the red soil samples, and therefore the effect of soil acidification upon the soil ecological toxicity of organophosphorus pesticides will be deduced. Furthermore, by using the technology of chromatographic detection, molecular biology and molecular simulation, the organophosphorus pesticide environmental behavior, the absorption and metabolism of E.foetida for organophosphorus pesticides, as well as the inhibition effect of organophosphorus pesticides on acetyl cholinesterase activity and its inhibition mechanism will be further investigated. Based on above results and using multivariate linear regression analysis, the mechanism of ecological toxicity varies at different acidification soil samples will be explored from the point of view of bioavilibility, toxicodynamics and toxicokinetics, respectively. It is obvious that the results of this project will be helpful to accurately evaluate the soil ecological toxicity of organophosphorus pesticides in the red soil zone.

酸化加剧是红壤的典型特征并已成为影响农业生产的重要因素之一。农药是农业生产中被人们广泛使用的生产资料，研究表明农药大多有土壤生态毒性，但酸化加剧下红壤中农药的生态毒性如何变化及其变化机制却尚不明确。为此，项目以赤子爱胜蚓为研究对象，有机磷农药为污染物，测定有机磷农药对赤子爱胜蚓的个体、生化及细胞水平毒性效应，揭示红壤酸化加剧下有机磷农药土壤生态毒性的变化规律；在此基础上，运用色谱分析、荧光光谱及分子模拟等技术，探明不同酸化程度红壤中有机磷农药的生物有效性、毒代动力学及毒效学特征；研究酸化红壤中有机磷农药的环境行为、吸收与代谢特征、有机磷农药-乙酰胆碱酯酶的结合作用与结合模式，探明酸化加剧下有机磷农药的生物有效性、毒代动力学及毒效学变化的原因，基于多元回归分析，最终揭示红壤酸化加剧下有机磷农药对赤子爱胜蚓毒性变化的毒理学机制。项目成果可为评价红壤中有机磷农药生态风险提供科学依据和理论支撑。

酸化加剧是红壤的典型特征并已成为影响农业生产的重要因素之一。农药是农 业生产中被人们广泛使用的生产资料，研究表明农药大多有土壤生态毒性，但酸化加剧下红 壤中农药的生态毒性如何变化及其变化机制却尚不明确。为此，项目以赤子爱胜蚓 (E. fetida) 为研究对象，三种典型有机磷农药(毒死蜱、乐果及三唑磷)为污染物，测定了有机磷农药对赤子爱胜蚓的个体、生化及细胞水平毒性效应，进而揭示红壤酸化加剧下有机磷农药土壤生态毒性的变化规律。研究结果表明，红壤酸化导致有机磷农药对赤子爱胜蚓的毒害作用增强。在此基础上，运用色谱分析、荧光光谱及分子模拟等技术，探明了不同酸化程度红壤中有机磷农药的生物有效性、毒代动力学及毒效学特征；研究酸化红壤中有机磷农药的环境行为、吸收与代谢特征、有机磷农药-乙酰胆碱酯酶的结合作用与结合模式，探明了酸化加剧下有机磷农药的生物有效性、毒代动力学及毒效学变化的原因，基于多元回归分析，最终揭示了红壤酸化加剧下有机磷农药对赤子爱胜蚓毒性变化的毒理学机制。即，红壤酸化改变了有机磷农药的生物有效性和毒效学，进而导致毒性加大。其中生物有效性主要通过酸化过程中水解及生物降解的变化所导致的，毒效学的变化主要是通过有机磷农药和乙酰胆碱酯酶的结合模式和结合能的改变所导致的。此外，项目也探明了红壤酸化溶出的金属离子对发光菌的慢性毒性兴奋效应作用及其作用机制。项目成果可为准确评价红壤中有机磷农药生态风险，理解其毒性响应的作用机制提供科学依据和理论支撑。