纳污湿地表层沉积物中重金属形态研究

Heavy Metals Speciation Analysis in the Surface Sediments from Polluted Wetland

采用Tessier法提取了武河湿地表层沉积物中重金属元素Cu、Zn、Pb、Hg、Cd,对其形态分布特征和相关性进行了分析,并利用潜在生态风险指数法对武河湿地表层沉积物中重金属污染进行了综合性评价分析,结果表明:各元素主要以残渣态形式存在,其平均含量均在80%以上;Hg活性态含量为0.098 mg/kg,低于环境背景值,环境危害轻微;相关分析表明碳酸盐结合态的Cu、Zn、Pb、Cd的污染源相似,有机结合态的Cu、Zn、Cd污染源相近,残渣态Cu、Zn、Pb污染源相近,残渣态Pb和Cd污染源相似或相近;各重金属元素迁移能力表现为Cd(5.40)>Pb(5.22)>Zn(2.31)>Cu(0.94);各元素的潜在生态风险表现为Cd>Cu>Zn>Pb,且Cd、Pb属于生物毒性显著的元素,对于其引起的污染更应该加倍重视。

Heavy metals such as Cu, Zn, Pb, Hg, Cd in surface sediments of Wuhe Wetland was extracted by Tessier method, and the morphological distribution characteristics and correlation were analyzed. The potential ecological risk index was used for the evaluation and analysis of heavy metals pollution in the surface sediments of the Wetland. The results indicated that each element existed mainly in the form of residue, with average content more than 80 %.The content of active state Hg was 0.098 mg/kg, lower than the background value of environment, which has little effect on the environment.Correlation analysis showed carbonate fraction of Cu, Zn, Pb, Cd had similar sources of pollution, and organic fraction of Cu,Zn, Cd had similar sources. Residual Cu, Zn, Pb pollution sources were similar, and residual Pb and Cd pollution sources were similar. The migration of heavy metals was expressed as Cd（5.40） Pb（5.22） Zn（2.31） Cu（0.94）. Potential ecological risk of the elements was expressed as Cd Cu Zn Pb, and the toxicity of Cd, Pb are significant for the pollution, which should be paid particular attentions.