Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Avenida Reina Mercedes 10, P.O. Box 1052, 41080 Sevilla, Spain.
J Agric Food Chem. 2010 Jul 14;58(13):7893-901. doi: 10.1021/jf100760s.
The use of pesticides in agriculture has become a source of pollution of soil and water in the last decades. Extensive pesticide transport losses due to leaching and runoff produce nonpoint source contamination of soils and water. One of the soil processes that reduce pesticide transport losses is adsorption by soil particles; therefore, enhancement of pesticide retention by soil can be used as a strategy to attenuate the environmental impact of pesticides. In this work, organoclays were prepared by treating Wyoming montmorillonite (SWy-2) and Arizona montmorillonite (SAz-1) with different organic cations and were assayed as soil amendments to enhance the retention and reduce the leaching losses of the herbicide fluometuron [N,N-dimethyl-N'-[3-(trifluoromethyl)phenyl] urea] in soils. Two agricultural soils from Southern Spain were selected for being high-risk scenarios of ground and surface water contamination. First, a batch adsorption study was conducted to identify organoclays with high affinity for fluometuron. Among the different organoclays assayed, spermine-treated Wyoming montmorillonite (SW-SPERM) displayed high and reversible adsorption of fluometuron and was selected as an amendment for subsequent persistence, leaching, and herbicidal activity experiments of fluometuron with unamended and amended soils. Amendment of the soils with SW-SPERM at rates of 1%, 2%, and 5% greatly enhanced fluometuron retention by the soils and retarded fluometuron leaching through soil columns. Incubation experiments revealed that the persistence of the herbicide in the amended soils was similar to that in unamended soils and that most of the herbicide was ultimately available for degradation. Bioassays demonstrated that the reduced leaching losses of fluometuron in soils amended with SW-SPERM may result in increased herbicide efficacy if heavy rainfall events occur shortly after herbicide application.
在过去几十年中，农业中农药的使用已成为土壤和水污染的一个来源。由于淋溶和径流，大量农药运输损失导致土壤和水的非点源污染。减少农药运输损失的土壤过程之一是被土壤颗粒吸附；因此，增强土壤对农药的保留能力可以作为减轻农药环境影响的一种策略。在这项工作中，通过用不同的有机阳离子处理怀俄明蒙脱石（SWy-2）和亚利桑那蒙脱石（SAz-1）来制备有机粘土，并将其用作土壤改良剂，以增强对莠去津[ N，N-二甲基-N'-[3-（三氟甲基）苯基]脲]的保留并减少其在土壤中的淋溶损失。从西班牙南部选择了两种农业土壤，作为地下水和地表水污染的高风险情景。首先，进行了批吸附研究，以确定对莠去津具有高亲和力的有机粘土。在所测试的不同有机粘土中，腐胺处理的怀俄明蒙脱石（SW-SPERM）对莠去津表现出高且可逆的吸附作用，并被选为随后用未处理和处理过的土壤进行莠去津的持久性，淋溶和除草活性实验的添加剂。将 SW-SPERM 以 1％，2％和 5％的比例添加到土壤中，可大大增强土壤对莠去津的保留能力，并通过土壤柱延缓莠去津的淋溶。孵育实验表明，在添加 SW-SPERM 的土壤中，除草剂的持久性与未添加土壤相似，并且大部分除草剂最终可用于降解。生物测定表明，如果在施药后不久发生强降雨事件，那么在添加 SW-SPERM 的土壤中莠去津淋溶损失减少可能会导致除草剂效果提高。
