根际环境对除草剂扑草净环境归趋的影响评价

植物保护产品（PPP）需要经过严格的监管评估，以确保它们不会对环境造成不可接受的风险。阐明化学品在土壤中的命运和行为是环境风险评估的一个组成部分。土壤中PPP活性物质降解首先在实验室研究中进行评估（通常遵循OECD 307实验导则）。但指导性实验室研究中的条件与农业使用中的条件相差甚远，而目前还没有评估作物根系的贡献。在这里，我们将代表三种不同作物类型的有效植物根系整合到OECD 307实验设计中，以评估它们对除草剂PPP降解的影响。在所有三种种植体系中，母本残留的下降速度和不可提取残留的形成速度都显著加快。这导致50%降解时间（DT50）在黑麦草和辣椒的存在下降低约一半，在红三叶的存在下减少约三分之一。这些发现表明植物及其相关的根系网络对PPP降解有显著影响。基于这些数据，需要将植物根系纳入更高层次的研究，在标准化实验室研究设计中增加更大的环境现实性，进而有助于改进环境风险评估过程。

EVALUATION OF THE RHIZOSPHERE CONTRIBUTION TO THE ENVIRONMENTAL FATE OF THE HERBICIDE PROMETRYN

Plant protection products (PPPs) undergo rigorous regulatory assessment to ensure that they do not pose unacceptable risks to the environment. The elucidation of the fate and behavior in soil is an integral part of this environmental risk assessment. PPP active substance degradation in soil is first assessed in laboratory studies (typically following the OECD 307 test guideline). Conditions in guideline laboratory studies are far removed from those occurring under agricultural use and the contribution of crop roots is currently not assessed. Here we integrate viable plant root systems, representative of three different crop types into the OECD 307 test design to assess their impact on the dissipation of the herbicide prometryn. Significantly faster decline of parent residue and higher formation of non-extractable residues were observed in all three planted systems. This led to a reduction in the dissipation time to 50% (DT50) by approximately one half in the presence of rye grass and hot pepper and by about one third in the presence of red clover. These findings imply that plants and their associated root networks can have a significant influence on PPP dissipation. Based on these data, greater environmental realism could be added to the standardized laboratory study design by the inclusion of plant root systems into higher tier studies which, in turn, could serve to improve the environmental risk assessment process.