Mercury alters the bacterial community structure and diversity in soil even at concentrations lower than the guideline values
The concentrations of mercury and cadmium in surface soil along the three ring road with high traffic density from Beijing, China, were investigated. The concentrations of cadmium and mercury in urban soils were in the range of 0.086-1.59 and 0.16-3.68 mg kg(-1), which exceeded the upper limits of potential toxic elements concentration for agricultural soils of China (PTE-MPC). The metal elements of cadmium and mercury showed similar spatial distribution and seasonal variations. Concentrations of cadmium and mercury in surface soil along the three ring road were significantly higher than previous reported values, which was attributed to the increased traffic density in Beijing. Results from this study demonstrated that the soil of the three ring road had endured severe cadmium and mercury pollution.