大型铜尾矿库区节节草(Hippochaete ramosissimum)根际土壤重金属形态分布与影响因素研究

Distribution of heavy metals forms and its affecting factors in rhizosphere soils of Hippochaete ramosissimum in large-scale copper tailings yard

通过野外调查和实验分析,对安徽省铜陵市铜官山铜尾矿库、狮子山铜尾矿库及狮子山铜尾矿库周边农田3处生长的节节草根际与非根际土壤中重金属(Cu、Cd、Pb、Zn)的形态、含量和分布进行了研究.结果表明,节节草根际与非根际土壤重金属的主要形态分布基本一致,均表现为矿物态含量占据了重金属全量的大部分,而交换态含量偏低.与非根际土壤相比较,根际土壤中交换态、有机态重金属所占比例显著增加,其中Cu的有机结合态所占比例增加了53.25%、Cd、Pb的有机结合态所占比例增加超过17%,Zn则增加了5.67%;与此同时,碳酸盐结合态和铁锰氧化物结合态含量有所下降.统计分析表明,Cu、Cd、Pb、Zn在根际土壤中的形态分布与土壤pH值、有机质含量、植物生长等因素密切相关.

Based on the field investigation and laboratory analysis, it was studied that the forms, contents and distribution of Cu, Pb, Cd and Zn of rhizosphere and non-rhizosphere soils of H. ramosissimum in Tongguanshan copper railings yard, Shizishan copper railings yard and the farmland beside Shizishan copper railings yard of Tonglin City, Anhui Province. The results showed that distribution of different forms of the heavy metals of rhizosphere and non-rhizosphere soils of H. ramosissimwn had a similar trend. It indicated that the contents of residual had occupied the great part of heavy metals, and the exehangeable had a few. Compared with non-rhizosphere soils, the contents of organic combined and exchangeable in rhizosphere soils of H. ramosissimum had increased, among them, the organic combined of Cu increased 53.25% , Pb and Cd increased more than 17% , and Zn 5.67% in average. At the same time, the contents of carbonate combined and Fe-Mn oxides combined decreased. The major factors that effected on the chemical forms of heavv metals in rhizosohere soils of H. ramosissimum were pH, organic matter and the growth of plant etc.