大冶湖内湖表层沉积物重金属分布及污染评价

摘要

选择大冶湖内湖(红星湖)为研究对象,采用BCR连续提取法和HCl-HNO3-HF-HClO4湿法消解以及火焰原子吸收分光光度法测定大冶湖内湖表层沉积物中8种重金属( Cu、Zn、Pb、Cd、Co、Ni、Mn、Fe)不同赋存形态的含量,并分析其空间分布特征,利用地质累积指数法和潜在生态危害指数法评价表层沉积物中重金属污染及其潜在生态危害程度。结果表明,大冶湖内湖表层沉积物中Cu、Zn、Pb、Cd、Co、Mn这6种重金属均主要以可提取态形式存在,各重金属元素生物有效性即可提取态含量顺序为：Cd>Mn>Cu>Co>Pb>Zn, Ni和Fe主要以残渣态形式存在；沉积物中Cu、Zn、Pb、Cd、Ni、Mn这6种重金属元素均有一定程度的富集,其中Cd的富集程度最为严重,且具有较强的生态危害,其次是Pb、Cu、Zn、Ni污染也较严重,Co、Mn和Fe污染则较为轻微。此外,上覆水体中Cd、Pb污染也较严重,沉积物中重金属析出会导致水质恶化。%The Inner Lake of Daye Lake ( Hongxing Lake) was selected for researching on the content of dif-ferent chemical speciation of heavy metals ( Cu,Zn,Pb,Cd,Co,Ni,Mn,Fe) in surface sediments of the Daye Lake which were analyzed by Atomic Absorption Spectroscopy ( AAS) using BCR sequential extraction meth-od and HCl-HNO3 -HF-HClO4 wet digestion. And pollution of heavy metals and potential ecological risk of these elements in surface sediments were evaluated by the geo-accumulation and potential ecological risk index. The results indicated that such six heavy metals as Cu, Zn, Pb, Cd, Co, Mn are mainly extractable form,bioavailability of each element,that is,sort of extractable content:Cd>Mn>Cu>Co>Pb>Zn,Ni and Fe mainly exist in residual form;Cu,Zn,Pb,Cd,Ni,Mn six heavy metals elements in surface sediments of the Daye Lake,the enrichment of Cd is the most serious and has a strong ecological harm,followed by Pb,Cu, Zn,Ni,Co,Mn and Fe are relatively minor. Cd,Pb in lake water is also more serious that indicants heavy metals release from sediments can lead to deterioration of water.