Sondhia Shobha, Khare Rishi Raj
Directorate of Weed Science Research, Adhartal, Jabalpur, M.P., 482004, India,
Environ Monit Assess. 2014 Oct;186(10):5969-76. doi: 10.1007/s10661-014-3832-4. Epub 2014 May 30.
The ability of herbicides to be adsorbed by the soil and sediment and their tendency to be desorbed are some of the most important factors affecting soil and water contamination. Therefore, a sorption study was conducted to evaluate the adsorption of cyhalofop-butyl, butyl (2R)-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propanoate, in the sandy clay loam and clayey soils using a batch equilibrium method. The adsorption of cyhalofop-butyl was found positively related with the clay and organic carbon content. Freundlich constants (Kf) of cyhalofop-butyl in the clayey and sandy clay loam were found to be 13.39 and 2.21, respectively. Sorption coefficients (Koc) and distribution coefficients (Kd) were found to be 265.38 and 2,092.79, and 1.38 and 11.48, for sandy clay loam and clayey soils, respectively. The adsorption isotherm suggested a relatively higher affinity of cyhalofop-butyl to the adsorption sites at low equilibrium concentrations. The low value of the soil organic carbon partition coefficient (Koc) of cyhalofop-butyl in the sandy loam soil suggested its weaker adsorption in soil and thus increased its risk of mobility into water sources; hence, it should be used judiciously to prevent groundwater contamination.
除草剂被土壤和沉积物吸附的能力及其解吸趋势是影响土壤和水污染的一些最重要因素。因此，采用批量平衡法进行了一项吸附研究，以评估氯氟吡氧乙酸丁酯（(2R)-2-[4-(4-氰基-2-氟苯氧基)苯氧基]丙酸丁酯）在砂质粘壤土和粘土中的吸附情况。结果发现，氯氟吡氧乙酸丁酯的吸附与粘土和有机碳含量呈正相关。氯氟吡氧乙酸丁酯在粘土和砂质粘壤土中的弗伦德利希常数（Kf）分别为13.39和2.21。砂质粘壤土和粘土的吸附系数（Koc）和分配系数（Kd）分别为265.38和2092.79，以及1.38和11.48。吸附等温线表明，在低平衡浓度下，氯氟吡氧乙酸丁酯对吸附位点具有相对较高的亲和力。氯氟吡氧乙酸丁酯在砂壤土中的土壤有机碳分配系数（Koc）值较低，表明其在土壤中的吸附较弱，从而增加了其迁移到水源中的风险；因此，应谨慎使用以防止地下水污染。
