沂河表层底泥重金属污染及其风险性评价

Distribution and Ecological Risk Assessment for Heavy Metals in Superficial Sediments of Yihe River

为了解临沂沂河干流小埠东橡胶坝至汤头段滨河大道开发造成的重金属污染状况,用火焰法原子吸收分光光度法对河道内表层底泥的重金属含量进行了研究,并采用地积累指数（Igeo）和潜在风险指数（RI）两种指标相结合的方法对其进行安全风险评价.结果表明,汤头至小埠东段河道内重金属污染以Cd为主,阳光沙滩呈极强污染,北外环桥和汤头呈强度污染,解放路桥、鸿福寺和新河村呈中～强度污染;单一元素潜在生态风险因子（Eir）评价阳光沙滩为极强生态污染,其他各点为很强生态污染;其次是Pb,在阳光沙滩呈极强污染,解放路桥、北外环桥、新河村和汤头为中度污染,鸿福寺为轻～中度污染.Eir评价在阳光沙滩处为强生态污染,其余各点轻微生态污染.依据潜在生态风险指数RI将河道分成三个风险功能区：解放路桥、鸿福寺、新河村为中等污染区,北外环桥、汤头为重污染区,阳光沙滩为极重污染区.

To explore the trend of the changes in heavy metal pollution caused by the development of riverside in Yihe rever.The determination of the heavy metal distribution of the superficial sediments was carried out by flame Atomic absorption spectrophotometry.The potential ecological risk index（RI） and geological acumination index（Igeo）,as the quantitative diagnostic tools,were used to evaluate the pollution degree of various heavy metals in the sediments.The results show the cadmium（Cd）pollution in the Tangtou to Xiao bu dong was the primary,and the sun beach was the strongest pollution,the north loop＇s bridge and tangtou was strong pollution,the liberation road＇s bridge and hongfu monastery and xinhe village were middle to strong pollution; the sun beach was the strongest ecological pollution by Eirevaluation,other points was strong ecological pollution.Secondly,plumbum（Pb）,in sun beach was the strongest pollution,and in liberation road＇s bridge,north loop＇s bridge,xinhe village and tang tou were moderate pollution,in hongfu monastery was middle to strong pollution; the sun beach was strong ecological pollution,and other points was minor ecological pollution.The results showed the distribution of pollutants in the sediments could be divided into three sections with different ecological risk characteristics： the medium pollution area in liberation road＇s bridge,hongfu monastery and xinhe village; the heavy pollution area in north loop＇s bridge and tangtou; the heavier pollution area in sun beach.