Distribution characteristic and assessment of soil heavy metals in Ulaanbaatar, Mongolia

The main purpose of this study was to investigate the current status of heavy metal pollution of the soil in Ulaanbaatar, the capital city of Mongolia. The pollutions of heavy metals in urban soils are affected by multiple factors including land uses, air pollution, household solid wastes, and automobiles. Total twenty-two soil samples were collected in a depth of 0-5 cm of soil surface from different parts of the city and analyzed for their As, Cr, Pb, Zn, Ni, Cu, Co, V, Ca, Mn, Fe, and Al. The concentrations of these metals were in the range of 5.0–45.0 mg/kg for As, 110.0 –757.0 mg/kg for Cu, 4.0–72.0 mg/kg for Pb, 47.0–82.0 mg/kg for V, 5.0–7.50 mg/kg for Co 9.0–21.0 mg/kg for Cr, and 66.0–260.0 mg/kg for Zn, respectively. The concentrations of Cu and As at all the sampling sites were exceeded the permissible level (100 mg/kg for Cu, 6 mg/kg for As). Concentrations of Pb, V, Co, Cr, and Zn at several sites exceeded the permissible level (Mongolian soil standard (MNS5850:2008)). The extent of soil metal contamination was assessed using the crustal enrichment factor (EFc). The EFc values for Cu were significantly high (e.g., 11.67–55.24) at studied sites, indicates that high degree of Cu contamination from anthropogenic sources. The main sources of Cu in urban can be tire abrasion, the corrosion of metallic parts of cars, lubricants and industrial and incinerator emissions. Arsenic (As) had the second highest EF values among metals studied (2.52–23.5). The source of As pollution in soil appears to be the coal combustion in power plants and stoves in Ger district. Lead (Pb), Zn, and Ni exhibited moderate enrichment (average EF values were between 3.01-4.75). This enrichment may be related to the remarkable increase in the number of used vehicles and the increase in the use of leaded fuel in recent years. The other elements (Co, Cr, Mn, Fe Ca. Ni and V) displayed relatively lower EF values (EF<1 or close to 1) indicating that these metals in soil are originated from natural sources dominantly.

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Author Ө.Билгүүн
Maintainer А.Бадам
Last Updated September 24, 2018, 10:09 (UTC)
Created September 24, 2018, 10:09 (UTC)