农药阿维菌素在土壤中的吸附特性

Adsorption Characteristics of Pesticide Abamectin in Soil

为了全面评价农药阿维菌素的环境行为,采用Freundlich吸附等温方程研究了农药阿维菌素在土壤中的吸附特性。结果表明,阿维菌素在4种土壤上的吸附等温线均为直线,说明吸附可能与其在土壤有机质中的分配作用有关;阿维菌素在腐植酸上的吸附要远强于土壤吸附,进而可以推测腐植酸对其在土壤上吸附的贡献率要远大于其他因素;降低水土比可以增加阿维菌素在腐植酸和土壤上的吸附,只是由于土壤对阿维菌素的吸附能力更小,使其影响不如腐植酸那样明显。

Abamectin is one pesticide widely used all over the world today, hut its some important environmental behaviors, such as adsorption characteristics in soil, have not been reported until now. In order to comprehensively evaluate the environmental security of abamectin, its adsorption characteristics in four kinds of soils were studied with Freundlich equation. The results showed that in four kinds of soils, the adsorption isotherms for abamectin were all straight lines, the correlated coefficients being more than 0.9, which indicated that the adsorption was related to the distribution action of abamectin in soil organic matter. The adsorption of abamectin in humic acid was greatly stronger than that in soil, with the adsorption coefficient （Kf） being twenty-four times of that in soil, which implied that humic acid played a more important role than other factors in soil. Adsorption of abamectin in humic acid and soil increased with the decrease of solution/soil （S/L） ratio, but humic acid had more obvious influence since its stronger adsorption ability. The adsorption coefficient （Kf） in humic acid at the ratio of S/L=1： 100, was more than ten times of that at S/L=1：20, while the adsorption coefficient （IG,） in Huajiachi soil at S/L=1：10 was only more than twice of that at S/L=1：5.