Using geoaccumulation index to study source profiles of soil dust in China.

Source apportionment studies of TSP (atmospheric particulate matter with aerodynamic diameters < or = 100 microm) and PM10 (atmospheric particulate matter with aerodynamic diameters < or = 10microm) have revealed that soil dust is an important source of these particulates in China. In this study, the contamination of soil dust was assessed through the use of a geoaccumulation index (I(geo)). The mass concentration profiles of 17 elements (Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Ba, and Pb) were established for urban soil dusts. Geochemical compositions of soils from 15 cities were used to represent background urban soil compositions. The results of this study indicated that a number of cities are severely polluted by particulates containing Ca, Cr, Ni, and Cu in both size fractions (TSP and PM10). Contamination with Zn, Pb, Co, and Br was moderate to severe (I(geo) > 2). The Al and Fe concentrations were not high enough for them to be considered contaminants.