Xiao Shenglan, Gong Yishu, Li Zijian, Fantke Peter
School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong 510275, People's Republic of China.
Department of Mathematics, Duke University, Durham, North Carolina 27708, United States.
J Agric Food Chem. 2021 Mar 31;69(12):3607-3616. doi: 10.1021/acs.jafc.1c00151. Epub 2021 Mar 17.
To explore pesticide uptake from soil into a growing potato, a moving-boundary dynamic model is proposed on the basis of the radical diffusion process of a chemical to a sphere. This model, which considers the logistic growth of the potato tuber, describes two hypothetical processes of chemical diffusion within a growing tuber. The model was tested in an illustrative case study for an application of chlorpyrifos. Results indicate that the distribution of chlorpyrifos concentrations along the potato radius is significantly affected by the tuber development. In comparison of our results to results from a classic model using a fixed boundary, the proposed dynamic model yields a quick and big jump for both the average concentration and bioconcentration factor (BCF) of chlorpyrifos in the potato as a result of the sigmoid expansion boundary. Overall, the dynamic model predicts that chlorpyrifos BCFs in the potato at harvest are higher than those using the classical model. In comparison of model results to measured uptake of chlorpyrifos into potato at harvest, the dynamic model shows better performance than the classical model. Our results provide a new perspective on pesticide uptake into potatoes and inform human health risk assessment for pesticides applied at different tuber growth stages.
为了探究土壤中的农药向生长中的马铃薯的吸收情况，基于化学物质向球体的自由基扩散过程，提出了一个移动边界动态模型。该模型考虑了马铃薯块茎的逻辑生长，描述了化学物质在生长中的块茎内扩散的两个假设过程。在一个毒死蜱应用的示例案例研究中对该模型进行了测试。结果表明，毒死蜱浓度沿马铃薯半径的分布受块茎发育的显著影响。将我们的结果与使用固定边界的经典模型的结果进行比较，由于S形扩展边界，所提出的动态模型使马铃薯中毒死蜱的平均浓度和生物富集系数（BCF）都有快速且大幅的跃升。总体而言，动态模型预测收获时马铃薯中的毒死蜱BCF高于使用经典模型的情况。将模型结果与收获时毒死蜱向马铃薯中的实测吸收情况进行比较，动态模型的表现优于经典模型。我们的结果为农药向马铃薯中的吸收提供了新的视角，并为在不同块茎生长阶段施用农药的人体健康风险评估提供了信息。
