2,4-二氯苯氧基乙酸在土壤中的吸附淋溶特性  

Adsorption and Leaching Behavior of Herbicide 2,4-Dichlorophenoxyacetic Acid in Soils

作　　者：吴星卫[1,2] 单正军[2] 孔德洋[2] 薛韵涵[3] 

机构地区：[1]南京农业大学资源与环境科学学院,江苏南京210095 [2]环境保护部南京环境科学研究所,江苏南京210042 [3]东南大学能源与环境学院,江苏南京210096

出　　处：《农业环境科学学报》2009年第4期691-695,共5页Journal of Agro-Environment Science

摘　　要：农药在土壤中的吸附和淋溶特性是评价其环境行为的重要指标,特别是决定了其在土壤中的迁移性。本文分别利用振荡平衡法和柱淋溶法研究了2,4-二氯苯氧基乙酸(2,4-D)在不同土壤中的吸附和淋溶特性及其影响因素。结果表明,2,4-D在3种供试土壤上的吸附特性能较好地用线性吸附等温线拟合,吸附常数Kd在0.95～1.54L·kg-1之间,很难被土壤吸附。影响2,4-D在土壤中吸附的因素主要是土壤pH值,其次是有机质含量。土壤pH值增高,离子态的2,4-D量增加,吸附减弱;2,4-D在土壤中具有较强的淋溶性,影响其淋溶性能的主要因素是土壤pH值,pH值越高,淋溶性能越强。The sorption and leaching of pesticides on and in soils, which are linked with physicochemical properties of pesticides and soil significantly, they will influence the fate and behavior of the chemicals in environment strongly. 2,4-Dichlorophenoxyacetic acid（2,4-D）, one of the acids herbicides and widely applied in controlling the growth of broad leaved weeds, has a complex adsorption mechanism on soils, due to its complicated molecular and ionic states. In the study, sorption and leaching of 2,4-D in the soils in China were conducted by batch equilibrium experiments and column method, as to evaluate the fate about attenuation of the chemical in environment. The results showed that 2,4-D was hard to be adsorbed on soils, with K, values from 0.95 to 1.54L·kg^-1, and the sorption isotherm could be described as linear model. Soil pH play a dominant role on the sorption of 2,4-D on soils, in contrast to the content of soil organic carbon. The Kd values decreased as the increase of soil pH values, for the increasing fraction of anionic form from dissociated molecular state. The free energy changes （AG） were all less than 40 kJ·mol^-1, which showed that adsorption of 2,4-D was of a physical process. 2,4-D had a high potential in leaching and consequent risk in contaminating the groundwater, especially in alkaline soil, which should be paid a more attention.

关 键 词：2 4-二氯苯氧基乙酸 吸附 淋溶 

分 类 号：X592[环境科学与工程—环境工程]