Heavy Metals and Arsenic in Soils and Street Dust of the Southeastern Administrative District of Moscow: Long-Term Data

The soils and street dust of the Southeastern administrative district of Moscow were analyzed for chemical properties and the content of acid-soluble and mobile compounds of heavy metals (HMs) and arsenic over three time spans: the end of industrial (1995), transitional (2004 and 2012), and recent postindustrial (2017) periods of the city development. The acid–base properties of soils and street dust have not changed during this period. However, the content of exchangeable sodium has considerably increased (to 20-fold), as well as the contents of calcium and organic matter. The total HM and arsenic contents in soils and street dust tend to decrease because of a reduction in the number of industrial facilities and periodic replacement of lawn soils. Ag, Hg, Sb, Zn, and As have the highest clarkes of concentration in soils and Sb, Zn, Hg, Ag, Cu, Pb, Mo, As, Cd, Cr, and Ni, in street dust. The degree of extraction of the acid-soluble compounds of several HMs in soils and street dust is very high but it decreases from 1995 to 2017. The amount of mobile HM compounds has decreased. However, the share of soil and street dust samples with the Cu, Zn, and Pb mobile compounds exceeding the maximum permissible concentrations is still high.