腐植酸在土壤中迁移的模拟实验研究

浅层地下水中的腐植酸与人体健康密切相关,腐植酸在土壤中的迁移影响土壤和地下水中腐植酸含量。采用土柱模拟实验,研究了不同条件下腐植酸的迁移规律。结果表明,腐植酸的出水浓度随时间逐渐升高,最后趋于稳定;同一时间段内,初始浓度为15mg·L-1时的出水浓度比10mg·L-1时高,且早24h达到稳定浓度;淋滤液pH为9时的出水浓度比pH为4时高,且早16h达到稳定浓度;粉质粘土柱对腐植酸的吸附和阻滞作用大于砂壤土柱,出水浓度较低,晚32h达到稳定浓度;土层厚为5cm的土柱出水浓度高于15cm土柱,早32h达到稳定浓度。分析认为,土壤对腐植酸的吸附作用是出水浓度变化的主要原因,腐植酸和土壤的理化性质是影响腐植酸在土壤中迁移的主要因素。

Simulated Experiment on Transport of Humic Acid in Soil

Humic acid in groundwater is closely related to human health.The concentration of humic acid in soil and groundwater is affected by the transport of humic acid in soil.The transport of humic acid at different conditions was studied by soil column experiments.The results showed that the outlet concentration of humic acid increased over time,and finally reached stable;In the same time,when the initial concentration of humic acid solution was 15 mg·L-1,the outlet concentration was higher and reached steady concentration 24 h earlier than the one whose initial concentration was 10 mg·L-1;When the pH value of leacheate was 9,the outlet concentration was higher and reached steady concentration 16 h earlier than the one whose pH value was 4.The high clay content enhanced the adsorption and retard of humic acid in soils,the outlet concentration of silty clay column was lower and reaches steady concentration 16 h later than the sandy loam colum;When the thickness of soil was 5 cm,the outlet concentration was higher and reached steady concentration 32 h earlier than the one whose thickness was 15 cm.It was concluded that the adsorption was the main reason of outlet concentration changing.The physicochemical property of humic acid and soil was the primary factor of humic acid transport in soil.