污灌土壤中Pb、Cd形态的研究

ABSTRACTStudy of the Formation of Lead and Cadmium in the Soils lrrigated withSewage.

运用顺序提取法研究了一些污灌区土壤中Ｐｂ、Ｃｄ的化学形态分布及影响因素。石灰性污灌土壤０－２０ｃｍ土层中，Ｐｂ、Ｃｄ主要以碳酸盐结合态和硫化物残渣态存在，其次是有机结合态，交换态和吸附态较少。０－２０ｃｍ土层中，Ｐｂ的吸附态＞交换态，而Ｃｄ则相反。影响Ｐｂ、Ｃｄ形态分布的主要因素有ｐＨ、有机质含量、腐殖酸组成和碳酸钙含量等。西安污灌区土壤中的Ｃｄ明显增加，且主要为有机结合态，碳酸盐结合态则相对减少。但这种影响对Ｐｂ并不明显。

AbstractThe formation and distribution of Pb and Cd using sequential extrac-tion method and the factors affecting them in some soils irrigated with sew-age were studied. In the layer of 0 -20cm of calcareous soils Pb and Cdexisted mainly in carbonate and sulfide forms,the organically bound formyarked second,and the exchangeable and adsorbed forms came third.Theexchangeable form of Cd was greater than the adsorbed but that of Pb wasiust on the contrary. The major factors affecting the distribution of Pb andCd were pH,organic matter,humic acid and CaCO_3. The total content of Cdin the soil of the Xi'an sewage irrigation zone increased significantly,andit existed mainly in organically bound form,mean while its carbonate formdeceased.But the same results were not found for Pb.