In the present work, an existing vegetation/air/litter/soil model (SoilPlusVeg) was modified to improve organic chemical fate description in terrestrial/aquatic ecosystems accounting for horizontal and vertical particulate organic carbon (POC) transport in soil. The model was applied to simulate the fate of three pesticides (terbuthylazine, chlorpyrifos and etofenprox), characterized by increasing hydrophobicity (log KOW from about 3 to 7), in the soil compartment and more specifically, their movement towards surface and groundwater through infiltration and runoff processes. The aim was to evaluate the role of dissolved organic carbon (DOC) and POC in the soil in influencing the peak exposure of pesticides in terrestrial/aquatic ecosystems. Simulation results showed that while terbuthylazine and chlorpyrifos dominated the free water phase (CW-FREE) of soil, etofenprox was mainly present in soil porewater as POC associated chemical. This resulted in an increase of this highly hydrophobic chemical movement towards groundwater and surface water, up to a factor of 40. The present work highlighted the importance of DOC and POC as an enhancer of mobility in the water of poor or very little mobile chemicals. Further studies are necessary to evaluate the bioavailability change with time and parameterize this process in multimedia fate models.

中文翻译：

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模拟陆地和水生生态系统中农药的峰值暴露：溶解性有机碳和土壤中垂直颗粒运动的重要性。

在当前工作中，对现有的植被/空气/垃圾/土壤模型（SoilPlusVeg）进行了修改，以改善陆地/水生生态系统中考虑土壤中水平和垂直颗粒有机碳（POC）传输的有机化学命运描述。该模型用于模拟三种农药（萜丁嗪，毒死rif和etofenprox）的去向，其特征是增加了土壤区室中的疏水性（log KOW从约3增至7），更具体地说是它们通过渗透和渗透向地表水和地下水的运动。径流过程。目的是评估土壤中溶解有机碳（DOC）和POC在影响陆地/水生生态系统中农药峰值暴露方面的作用。模拟结果表明，虽然叔丁嗪和毒死rif占据了土壤的自由水相（CW-FREE），但依托芬普司作为POC相关化学物质主要存在于土壤孔隙水中。这导致这种高度疏水性的化学物质向地下水和地表水的迁移增加了多达40倍。目前的工作强调了DOC和POC作为增强贫乏或极少流动化学物质在水中迁移性的重要性。有必要进行进一步的研究以评估生物利用度随时间的变化，并在多媒体命运模型中对这一过程进行参数化。本工作强调了DOC和POC作为增强流动性差或很少的化学物质在水中的流动性的重要性。有必要进行进一步的研究以评估生物利用度随时间的变化，并在多媒体命运模型中对这一过程进行参数化。本工作强调了DOC和POC作为增强流动性差或很少的化学物质在水中的流动性的重要性。有必要进行进一步的研究以评估生物利用度随时间的变化，并在多媒体命运模型中对这一过程进行参数化。