污泥中重金属在棕壤和褐土上的淋洗特性的研究

通过测定室内土柱淋洗液分析了两种污泥在棕壤和褐土上的淋洗特性,测定项目主要包括pH、EC、DOC、重金属元素(Zn、Cu、Pb、Cd)。结果表明,施入污泥后土壤淋洗液的pH变化不大,土壤淋洗液的电导明显增大,随着淋洗次数的增多又逐渐恢复到原来的水平。有机质的含量和存在形式对金属的转移有显著的影响。其以固态存在时会增强对金属离子的吸附,但当以DOC形式存在时又会促进重金属的移动,增加对地下水的潜在威胁。由于棕壤与褐土在pH、EC、有机质含量、质地等方面的差别,污泥中的重金属在棕壤上比在褐土上更易被淋洗。

Leaching Characters of Heavy Metals in Brunisolic and Cinnamon Soils Receiving Sludge

Leaching ability of four heavy metals in brunisolic soil and cinnamon soil, respectively, was assessed by application of sludge onto the soils columns. The leachates were analyzed for pH, electrical conductivity (EC), dissolved organic carbon (DOC) and concentrations of four metals (Zn, Cu, Pb, Cd). The results showed that: when the sludge was applied to the soil, the leachates' pH had little variance, but EC increased significantly, then quickly returned to initial level. .The quantity and nature of organic matter had great impact on the leach ability of the metals. The solid-phase organic matter increased the absorption for the metals, while DOC enhanced the metals' mobility, increasing potential pollution to underground water. The metals in sludge exhibited easily to leach in brunisolic soil than in cinnamon soil, probably due to the difference of pH, EC, OM and texture of brunisolic soil and in cinnamon soil.