Assessment of Soil Pollution with Presumably Contaminating Elements in Moscow Recreational Areas Using Instrumental Neutron Activation Analysis

Urban ares are subjected to intensive pollution due to continuous anthropogenic activity. In order to assess the influence of thermal power plants and waste incineration plants on the City of Moscow recreational areas, the mass fractions of 37 major and trace elements were determined using instrumental neutron activation analysis in soil samples collected at two different depths in the vicinity of more potential contamination sources. Comparison of the mass fractions of determined elements with the Upper Continental Crust (UCC) evidenced a high similarity with the exception of Ca of which mass fraction, in some places, overcame a number of times the UCC one. The Discriminant Analysis was used to reveal similarities between the composition of collected soils samples. The distribution of major as well as of trace elements in analysed soils indicates their mixed origin. Contamination Factor (CF), Enrichment Factor (EF), Geoaccumulation Index (I-geo) and Pollution Load Index (PLI), all of them defined with respect to UCC, were used for a comprehensive evaluation of the soil pollution with presumably contaminating elements Cr, Ni, Zn, As, Sb and Hg. Among them, only in few places, CF reached a maximum values of 5.9 for Hg, EF of 13 and I(geo )of 3.12, both for Sb, but in different places, pointing towards an uneven distribution of contaminated areas. As, for the majority of places, the same indices were below or around the contamination thresholds, only for some locations the PLI exceeded 1.05, suggesting a moderate contamination localized in the vicinity of a few thermal power plants.