典型有色金属矿山城市小河流沉积物重金属形态分布及风险评估  

Fraction Distribution and Risk Assessment of Heavy Metals in Stream Sediments from a Typical Nonferrous Metals Mining City

作　　者：李如忠[1] 姜艳敏[1] 潘成荣[2] 陈婧[1] 徐晶晶[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009 [2]安徽省环境科学研究院,合肥230071

出　　处：《环境科学》2013年第3期1067-1075,共9页Environmental Science

基　　金：国家自然科学基金项目(51179042);安徽省环保厅环保公益项目(2011-010)

摘　　要：采用改进的Tessier连续提取法分析了铜陵市惠溪河表层沉积物中7种重金属(Cd、Cr、Cu、Zn、Ni、Pb、As)的形态分布,并以风险评价编码法(RAC)和平均沉积物质量基准系数法(SQG-Q)对沉积物重金属污染程度和生态风险进行评价.结果表明:①Cr和As主要以残渣态存在,Zn、Ni和Pb主要以残渣态和Fe-Mn氧化物结合态存在,Cu主要以有机结合态存在,Cd有机结合态的质量分数较低,其它几种形态大体接近.②Cd、Cr、Cu、Zn、Ni、Pb和As有效态的质量分数分别为46.48%、4.62%、4.05%、4.12%、9.17%、0.97%和0.03%;按照RAC判定,Cd对环境构成高风险,Cr、Cu、Zn和Ni的环境危害处于低风险水平,Pb和As则无风险.③惠溪河沉积物SQG-Q均值为10.42,远大于1.0,表明该河流具有非常高的潜在生物毒性效应;Cd、Cr、Cu、Zn、Ni、Pb和As的PEL-Q系数分别为4.23、1.14、20.75、6.04、2.33、4.58和41.71,表明7种重金属的潜在生物毒性很大,不利生物效应将频繁发生.A modified Tessier＇s sequential extraction procedure was used to investigate the fraction of seven types of heavy metals （ Cd, Cr, Cu, Zn, Ni, Pb, As） in the surface sediments from Huixi Stream in Tongling City, a typical non＇ferrous metals mining city, China. Based on speciation distribution analysis of these metals, contamination degree and ecological risk assessment of heavy metals were conducted by means of risk assessment code （RAC） and mean sediment quality guideline quotient （SQG-Q）. The results show that ： （1） Cr and As are major composed with residual fractions, Zn, Ni and Pb are mainly constituted of residual and bound to iron and manganese oxides fractions, and Cu is dominated by bounding to organic matter, while Cd exists in approximate mass fractions of exchangeable, bound to carbonates, bound to iron and manganese oxides, and residue. （2） Carbonate and exchangeable mass fractions ofCd, Cr, Cu, Zn, Ni, Pb and As reach 46.48%, 4.62%, 4.05%, 4.12%, 9.17%, 0.97% and 0.03%, respectively. According to the RAC, Cd is of high risk to the environment, Cr, Cu, Zn and Ni are of low risk to the environment, while Pb and As pose extreme low risk to the environment. （3） The SQG index, calculated with SQG-Q, is 10.42, which is far higher than the threshold value 1.0, indicating that the sediment in Huixi Stream has a very high potential for biological toxicity effect. The PEL-Q indexes corresponding to Cd, Cr, Cu, Zn, Ni, Pb and As approach 4.23, 1.14, 20.75, 6.04, 2.33, 4.58 and 41.71, respectively, suggesting that all these metals have great potentials for biological toxicity and the adverse effects will frequently occur.

关 键 词：重金属 风险评价编码法 生物可利用性 平均沉积物质量基准系数法 生物毒性 铜陵市 

分 类 号：X142[环境科学与工程—环境科学] X820.4