Heavy metals in urban grounds in Ekaterinburg (Russia)

Abstract

Problem Statement. Urban grounds have an artificial origin, they are formed as a result of construction activities, contain solid waste products and pollutants along with natural mineral and organic raw materials. Not all the cities have a system of registration of the urban ground types. The assessment of the pollution degree of urban grounds plays a key role in the environmental quality assessment in urban areas. The objective of the study is to conduct quantitative assessment of pollution with heavy metals for the urban grounds (on the example of Ekaterinburg, Russia). The material for the study is represented by the results of environmental engineering surveys conducted in Ekaterinburg in 2012–2015. The samples of the urban ground were collected with vertical stratification to a depth of 7 m in different geographical parts of the city. The content of Pb, Zn Cu, Mn and Ni, and the level of acidity were determined in the urban ground samples. Results. The analysis of vertical ground profiles showed a decrease in Pb, Zn and Ni content with increasing the depth. The accumulation of typical pollutants for urban environment (Pb, Zn and Cu) was found in the upper ground layer 0-20 cm. The metal content in the layer 0-20 cm was up to 5 times higher than the metal content in the lower horizons with a twofold decrease in metal concentration to depth of 1 m. In artificial ground in Ekaterinburg, there was a tendency to alkalization of soils with increasing depth (pH of the surface layer 0–20 cm was 6.5, when pH value was close to 8 at the depth > 4 m).