The Investigation Of Soil Heavy Mental Pollution Of The Second Ring Road In Beijing

As important components and precious resources, the soil which have direct relationship with humanity's survival and development is always been polluted and damaged. Among all kinds of soil pollution, the heavy mental pollution has been the global focusing issues. In order to catch the current soil pollution situation of the second ring road in Beijing, total concentration and each speciation's concentration of heavy metals including Cr, Cu, Zn, Cd, Ni and Pb in 46 soil samples collected from 23 sectors which have been marked on the map were investigated, and the pH of all the samples were also measured. The results showed that the average of total concentration of Cr, Ni and Cd are four times than these found in their corresponding background. The result showed that the concentration proportions of these six heavy metals in inert forms are more than 80%. In addition, two different kinds of methods were used to evaluate the heavy metals pollution in the second ring road. The results showed that the contamination degrees of Cr and Cd were higher than other heavy metals. The evaluation results of potential ecological risk index method showed that the pollution level of Cd is highest, and the pollution level of the south of second ring road is higher than other places. The risk assessment code based on chemical species implied that the potential bioavailability are Zn > Cd > Ni > Cu > Pb >Cr, the biological potential availability sequence got from the ratio of secondary phase and primary phase is Cd > Pb > Zn > Cu > Cr > Ni.