土壤中重金属镉锌铅复合污染的研究

POLLUTION OF CADMIUM, ZINC AND LEAD IN BROWN EARTH

采用吸附与解吸实验及盆栽试验，研究了在重金属镉、锌、铅复合污染条件下，棕壤对重金属的吸附、解吸规律，以及菠菜吸收重金属的特点。结果表明：棕壤对铅、锌的吸附分别符合Ｌａｎｇｍｕｉｒ、Ｆｒｅｕｎｄｌｉｃｈ方程，对镉的吸附用Ｌａｎｇｍｕｉｒ、Ｆｒｅｕｎｄｌｉｃｈ及Ｔｅｍｋｉｎ方程回归都不显著。重金属被吸附后的解吸率顺序为：Ｚｎ＞Ｃｄ＞Ｐｂ．Ｐｂ^（２＋）与吸附位结合的牢固程度较单一污染时大，而Ｃｄ^（２＋）和Ｚｎ^（２＋）较单一污染时小。土壤中锌含量的增加会降低菠菜对镉的吸收量。镉、锌、铅在土壤中的主要存在形态不同，菠菜对重金属的吸收受土壤中重金属存在形态的影响，这种影响较为复杂。＊，生长在重金属污染土壤上的作物，茎、叶中的重金属含量明显高于籽实中的含量［４］，对于叶菜而言，地上部分重金属的累积量很大，造成对人体健康的威胁。基于此，本文对沈阳市土壤中重金属镉、锌、铅的复合污染进行了研究。１材料与方法１．１土壤对重金属的等温吸附及解吸实验供试土样为棕壤，采样深度为１０－３０ｃｍ，土壤的基本性质见表１。用Ｃｄ（Ａｃ）２·２Ｈ２Ｏ。

The pollution of cadmium, zinc and lead in brown earth were studied. the Langmuir and Freundlich isotherms were fitted the adsorption data for lead and zinc respectively. None of them is suitable to cadmium. The order of desorption ration of the metals was: Zn>Cd>Pb.The binding of lead to the adsorption site was enforced with the presence of other metals. The fractionation, as well as their availabilities to spinach, of the metals are different from each other.