Speciation Analysis Of Heavy Metals In Soil In A Typical Industrial City, North-west China

Heavy metals in soils have been received increasing attention due to potential environmental and ecological consequences primarily. In recent years, heavy metal pollution in soil has been detected in more and more locations. Because of accumulation and migration, heavy metals in soil ether directly or indirectly harm the urban environment and human health. Xigu, a district of Lanzhou, is a primary industrial district, where lots of enterprises caused severe environmental pollution. Study on heavy metals pollution of Xigu District appears to be more and more important. This study is sought to assess the current status of heavy metals around of Lanzhou Aluminum Plant in Xigu District by investigations of their contents, speciation and potential risk assessment.The result from the distribution of heavy metals showed that the pollution of seven elements (Co,Cu,Mn,Ni,Pb,Zn,Cr) is the most serious, especially Mn. Pb caused low-level pollution. Content of all heavy metals in the soil decreases with the collection radius increasing, indicating the impact of production activities of Aluminium Plant related to the soil formation on the distribution of heavy metals. The result from speciation analysis of the heavy metals showed that all heavy metals exist in residual fraction in the soil. Cd, Mn and Cr exist in weak acid fraction and represent a major component. We should arouse great concern of Cd, Mn and Cr which are absorbed by plants easily. The ecological risk of Cd is the highest.