Department of Chemistry & Biochemistry, Utah State University, Logan, Utah 84322, United States.
Environ Sci Technol. 2021 Apr 20;55(8):4842-4850. doi: 10.1021/acs.est.0c07722. Epub 2021 Mar 29.
Pesticide dissipation from plant surfaces depends on a variety of factors including meteorological conditions, the pesticide's physicochemical properties, and plant characteristics. Models already exist for describing pesticide behavior in agriculture fields; however, they do not account for pesticide-specific, condition-specific foliar photodegradation and the importance of this component in such models has not yet been investigated. We describe here the Pesticide Dissipation from Agricultural Land (PeDAL) model, which combines (a) multiphase partitioning to predict volatilization, (b) a new kinetics module for predicting photodegradation on leaf surfaces under varying light conditions based on location and timing, and (c) a generic foliar penetration component. The PeDAL model was evaluated by comparing measured pesticide dissipation rates from field experiments, described as the time for the pesticide concentration on leaves to decrease by half (DT), to ones generated by the model when using the reported field conditions. A sensitivity analysis of the newly developed foliar photodegradation component was conducted. We also showed how the PeDAL could be used by applicators and regulatory agencies. First, we used the model to examine how pesticide application timing affects dissipation rates. Second, we demonstrated how the model can be used to produce emission flux values for use in atmospheric dispersion and transport models.
从植物表面消散的农药取决于多种因素，包括气象条件、农药的物理化学特性和植物特性。现已有用于描述农业领域中农药行为的模型；然而，这些模型并未考虑到特定农药、特定条件下的叶面光降解，并且该成分在这些模型中的重要性尚未得到研究。我们在这里描述了农业用地中农药消散（PeDAL）模型，该模型结合了（a）多相分配预测挥发，（b）根据位置和时间预测变化光照条件下叶面光降解的新动力学模型，以及（c）通用叶面穿透组件。通过将田间实验中测量的农药消散率（描述为叶片上农药浓度减半所需的时间（DT））与模型在报告的田间条件下生成的农药消散率进行比较，评估了 PeDAL 模型。对新开发的叶面光降解组件进行了敏感性分析。我们还展示了 PeDAL 如何被施药者和监管机构使用。首先，我们使用该模型研究了施药时间如何影响消散率。其次，我们展示了如何使用该模型生成排放通量值，以便在大气扩散和输送模型中使用。
