水溶性有机物在土壤剖面中的分馏及对Cu迁移的作用

Vertical Fractionation of Dissolved Organic Matter and Its Effect on the Transport of Cu in Cu-Contaminated Soils

通过室内土柱试验研究了DOM在土壤剖面中的“分馏”作用,DOM在纵向运移过程中的穿透行为及对污染的红壤和潮土中重金属Cu溶出效果的影响.结果表明,绿肥和猪粪DOM经过土柱后极性都有所降低,在潮土上的降低幅度较大,分别为11.4%和10.72%;DOM能够明显地增加污染土壤中Cu的溶出,且这种作用效果与DOM及土壤的性质有关,绿肥DOM的作用效果比猪粪DOM的强,整个淋洗过程中潮土上Cu的平均溶出量是红壤上的4.37倍(绿肥DOM)和3.03倍(猪粪DOM);由于微生物对DOM的分解作用,降低了DOM对土壤中Cu的溶出效果.

The vertical fractionation of DOM and its effect on Cu transport in acidic and calcareous Cu-contaminated soils were studied in column experiments. The results showed that the polarities of DOM derived from green manure and pig manure were obviously decreased by 11.4% and 10.72%, respectively, when they were leached through soil columns, especially in the calcareous soil. Dissolved organic matter can increase the dissolution of copper from the two copper-contaminated soils, but the dissolution effect was influenced by the properties of DOM and soils. For example, the ability of DOM derived from green manure to increase copper dissolution was stronger than that of DOM from pig manure. On average, the amounts of copper into effluent leached by green manure DOM or pig manure DOM in the column packed with a calcareous soil are 4.37 and 3.03 times higher than that in the column packed with an acidic red soil, respectively. In addition, it was observed that Cu dissolution from soils facilitated by DOM was decreased due to microbial degradation of DOM in soils.