欧美农药环境降解动力学评估方法比较

Comparison of Evaluation Method of Pesticide Environment Degradation Kinetics Used in EU and NAFTA

农药在环境中的降解行为是评估农药环境安全性的基础,农药的降解动力学通常以一级动力学模型描述。现有的环境暴露模型也均需要输入一级动力学模型的农药在土壤中50%消失时间(DT50)。但有时一级动力学模型不适用于描述农药在环境中,特别是土壤中的降解。因此欧盟和北美自由贸易区已发布了一系列关于使用非一级动力学模型计算DT50的导则。介绍了欧美降解动力学评估方法,并用多组降解数据比较了2种评估方法的区别。

Degradation of pesticide in the environment is a key factor in pesticide environmental risk assessment, and the degradation kinetics is often described by single first-order kinetics. The currently used exposure models re-quire a first order 50% disappearance time （DT50 ）. However, single first order kinetics may not appropriately de-scribe the pesticide degradation behavior in environment, especially in soil. In these cases, European Union （EU） and North American Free Trade Area （NAFTA） has developed a series of guidance documents including the use of non-first order kinetics in fitting pesticide degradation data to determine DT50 . This paper presents an introduction of ki-netics analysis procedures used by EU and NAFTA, and a comparison of the two approaches using various data sets.