Spatial Distribution, Contamination Levels, and Health Risks of Trace Elements in Topsoil along an Urbanization Gradient in the City of Urumqi, China

For this study, we collected a total of 77 topsoil samples from urban, suburban, and rural gradients in the Urumqi city area northwest China analyzed their concentrations seven trace elements: Arsenic (As), cadmium (Cd), nickel (Ni), lead (Pb), mercury (Hg), copper (Cu), Zinc (Zn). To assess compare contamination levels potential health risk elements along an urbanization gradient, employed pollution index assessment model introduced by US Environmental Protection Agency; also used geostatistical analysis to analyze spatial distribution patterns. The results obtained indicate that soil decreased order urban > suburban gradients. We found similar pattern Ni, Zn, Cd, Pb elements, with zonal pattern, while patterns As, Cu, Hg show high concentration patches many areas investigated study. Furthermore, based on identified concentrations, is heavily contaminated slightly Pb, Zn whereas it As gradient. non-carcinogenic for adults children decrease gradients, carcinogenic However, all more harmful children’s than adults. Overall, has had obvious effects accumulation soil, main factor among