Heavy Metal Pollution in Topsoil from the Baotou Industry Area and Its Potential Ecological Risk Evaluation

In order to understand the effect of industrial pollution in the Baotou industrial areas on heavy metal content in soils, correlation analysis was used to study the source of Cu, Zn, Pb, Cr, Cd, Mn, and Ni. The heavy metal pollution in the soils was assessed using the methods of Nemerow index and Hakanson's ecological risk index. The results show that the contents of these seven heavy metals are higher than the background values of soils in Inner Mongolia. The exceeding ratios of Cd, Mn, Ni contents in soil are 100%, and Cu, Pb, Zn, Cr were 97%, 93%, 93%, 53%, respectively. The pollution degree of single elements showed the order of Cd > Pb > Cu > Ni > Zn > Mn > Cr. Pb and Cd are strong pollution elements, whereas Cu, Zn, Ni are moderate pollution elements,Cr, Mn are minor pollution elements. The main sources of heavy metals (Cu, Zn, Cr, Mn, Ni) in soils of the industrial district were industrial pollutant discharge and transportation. Excluding the two sources mentioned previously, Pb and Cd are mainly attributed to the emissions of coal-fired flue gas. The potential ecological risk has the order of Cd > Pb > Cu > Ni > Cr > Zn > Mn. Among them, Cd is the most harmful heavy metal pollutant and should be addressed.