Search

This study investigates the elemental composition, organic carbon content, pH values, and particle size characteristics in 50 road dust samples collected from Tyumen, a large city in Western Siberia (Russia). The content of 62 major and trace elements was studied using atomic emission spectrometry (ICP-AES) и inductively coupled plasma spectrometry (ICP-MS). It was revealed that the dust has an alkaline reaction pH = 7.4–10.2 and low organic carbon content (0.07–2.9%). The grain size distribution of the road dust samples revealed that the predominant grain size fraction was of 100–250 μm. The content of small particles (PM2 and PM10) representing the greatest environmental hazard is minimal on roads with an average traffic intensity. Studies have shown that the main road dust pollutants in Tyumen are Ni, Sb, Cr, Zn, and Co. The average geoaccumulation index (Igeo) values are ranked as Ni (2.2) > Sb (1.5) > Cr (1.3) > Zn (0.4) > Co (0.4) > Cu (0.2). The contamination evaluation through enrichment factor (EF) calculation showed that road dust is highly enriched in Ni and significantly in Cr and Sb. More than 80% of Zn, Co, and Cu and more than 90% of Ni, Sb, and Cr come from anthropogenic sources. The average concentration of Ni and Cr in the road dust of Tyumen is one order of magnitude higher than in other cities of the Earth where similar studies were carried out. The high Ni content is associated with the composition of local soils and roadways, increased content in vehicle exhaust gasses, and abrasion of metal parts. Calculations of the total enrichment index Ze showed that the level of road dust pollution in most of Tyumen's territory is hazardous. [ABSTRACT FROM AUTHOR]

Abstract—: The major and trace element compositions of stratified frozen peatlands in the forest-tundra of Northeastern European Russia were determined for the first time. The upper level of trace element accumulation was confined to the active (seasonally thawed) layer owing to airborne contamination over a long time span and related to the bioaccumulation of Hg, Cd, Pb, Cu, and other heavy metals (HMs) by plants and humus materials. The character of element accumulation and migration in the active layer is controlled by the stability of HM humates. Under high-acidity conditions, HMs are highly mobile and migrate to the lower boundary of the active layer, which is indicated by an increase in the fraction of water-soluble forms of a number of elements. Analysis with a scanning electron microscope revealed the presence of spherical and semispherical particles up to 1 μm in size containing Pb, Zn, Cr, and Ni in the upper peat levels, which indicates an anthropogenic source of their input owing to long-distance and local transport of air masses. The central level of element accumulation was confined to peat layers in the permafrost zone (60-120 cm), where enrichment in As and Cd relative to the mean contents in the Earth's crust (and approximate permissible concentrations, APC, for soils) and accumulation of Fe, Al, S, and siderophile elements were observed. The source rocks of the peatlands are loams enriched in Cd, Zn, and As. The statistical analysis of relations of the contents of major and trace elements in the stratified peat horizons with the composition of peat-forming materials showed a significant contribution of the biogenic accumulation of elements. [ABSTRACT FROM AUTHOR]