摘要
为评估被用作白蚁预防药剂的毒死蜱和氰戊菊酯在土壤中的移动性,采用平衡吸附法和薄层层析法分别测定了两种农药在浙江宁波地区的东钱湖土(粉砂质壤土)、青岭土(粉砂质壤土)和象山土(粉砂质黏壤土)3种土壤中的吸附常数(Kd)和迁移率(Rf)。结果表明,两种供试药剂在东钱湖土中的吸附等温线线性化程度均较高,而在青岭土和象山土中的吸附等温线均近似于"L"型。从Kd和有机质吸附常数Koc的数值看,氰戊菊酯在土壤中的吸附作用主要受土壤有机质因素影响,而毒死蜱的吸附并非只受土壤有机质因素的影响。毒死蜱在3种供试土壤中的Kd和Rf值均高于氰戊菊酯。这表明由Kd值推测不同农药在土壤中的相对移动性可能会存在一定偏差。毒死蜱和氰戊菊酯在3种土壤中的Rf值由大到小的顺序为:东钱湖土>青岭土>象山土;而Kd值由大到小顺序为象山土>青岭土>东钱湖土。对Kd和Rf值与土壤理化性质的多元线性回归分析表明:1)土壤有机质含量和阳离子代换量在决定Kd和Rf值中所起的作用相互重叠;2)土壤有机质含量(或土壤阳离子代换量)和土壤黏粒含量是影响Kd和Rf值的关键因素,而土壤pH值对于Kd和Rf值无决定性影响。
Adsorption and mobility of two commonly used hydrophobic termiticides, chlorpyrifos and fenvalerate were studied in three soils including Dongqianhu soil （a hillside yellow silty loam）, Qingling soil （a yellow spot blue-purple silty loam）, and Xiangshan soil （a light sea coast silty clay loam）, using batch equilibrium technique and soil thin layer chromatography. The result indicated that Freundlish equations for Dongqianhu soil took a linear form, while the equations for Qingling soil and Xiangshan soil gave a form of ＂L＂ shape. Comparison between adsorption coefficient （Kd ） and organic carbon correlative adsorption coefficient K∝ suggested that adsorption of chlorpyrifos by soils was not only affected by organic matter （OM） but also by clay content, whereas soil adsorption of fenvalerate was affected mainly by OM. From Kd point of view, chlorpyrifos was more strongly adsorbed than fenvalerate by soil components, whereas judged from mobility factors （Rf） chlorpyrifos was more mobile in soils than fevalerate. It suggested that it was not reliable to infer relative mobility among pesticides. Mobility of both chlorpyrifos and fenvalerate in soils was in order of Dongqianhu 〉 Qingling 〉 Xiangshan as scaled by Rf, whereas adsorptive capacity of soils to both chlorpyrifos and fenvalerate was in order of Xiangshan 〉 Qingling 〉 Dongqianhu as scaled by Kd. Single- and multi- variable linear regressive indicated that： 1 ） There existed a functional superposition of OM and cation exchange capacity （CEC） in their determination of Kd and Rf. 2） Either OM and clay content, or CEC and clay content, was necessary and adequate precondition for determination of Kd and Rf. pH of soils was trivial in determination of Kd and Rf.
出处
《农药学学报》
CAS
CSCD
2007年第4期397-404,共8页
Chinese Journal of Pesticide Science
基金
宁波市青年科学基金(2004A20010)
关键词
毒死蜱
氰戊菊酯
吸附
迁移
土壤
chlorpyrifos
fenvalerate
adsorption
mobility
soil
