松花江一级阶地包气带岩性特征及其对农药吸附与降解的影响

Lithologic characteristics of the unsaturated zone and its impact on adsorption and degradation of pesticide in the first grade terrace of Songhua River

对松花江一级阶地包气带的岩性特征分析结果表明,三层介质均为砂土,有机质和粘土矿物含量较少,水的渗透系数由表层到深层显著增大。阿特拉津在三层介质中的吸附系数依次为1.2mL/g、0.6mL/g和0.2mL/g,自然降解半衰期为124d、153d和225d,能够长期残留在包气带中,构成对地下水的威胁。

The unsaturated zone is divided into three layers in which the media is mainly sandy soil. The amount of organic matter and clay mineral are relatively less. The value of permeability coefficients is getting larger from the surface to the deep layer distinctively. The results of the adsorption and the natural degradation experiments show that the adsorption coefficients of Atrazine in the three layers are 1.2 mL/g, 0.6 mL/g and 0.2 mL/g respectively, and the half-life periods of natural degradation are 124 d, 153 d and 225 d, respectively. The Atrazine can remain in the unsaturated zone for a long time and eventually result in groundwater pollution.