Eco-geochemical Assessment In The Urban Area Of Hohot And Baotou

Distribution of poisonous elements in soil and dust were investigated based on1:50000 soil and dust geochemical survey in the two cities: Hohhot and Baotou.Element concentrations in various pollution sources were found out based on the wetand dry deposition and other pollution endmembers. The harm of the environmentalpollution to the resident health was assessed through the analysis of the elementconcentration in the environmental media of wet and dry atmospheric deposition,inhalable particles, agricultural plants and human hair.It was found that soil and dust in the urban area were concentrated with Hg, Pb,Cu, Cd, C, Zn, P, Se and S. And also, REE element (such as Ce, La and Y),radioactive element (U and Th) and Fe family elements and F were also concentratedin the soil samples from Baotou. The concentrations for the most elements werehigher in the soil samples than those in the dust samples. The polluted area in Baotouis near the iron plant, aluminum plant, and the tailing dam. And the polluted area inHohhot is near the iron plant. Poisonous element in the endmember dust wasdecreasing as the sequence: smelting dust>coal combustion dust>transportationdust>falling dust>construction dust. The abnormal elements in the wet and dryatmospheric deposition in Baotou were Cr, Zn ,La, Ce, Cd, F and Se, and Pb, P, C, Cuwere also concentrated in some areas. The abnormal elements in Hohhot were Cd, Hg,Se, Pb, Zn, Cr and F.Dust samples from the urban area were concentrated of the mica, magnetite andhematite etc. and rare of the clay minerals such as kaolinite and illite. From thespeciation analysis, it was shown that Ni, Cr and Hg have low bio-availability and F,Cd, Pb, Zn and Cu have high bio-availability. Ionic and carbonate bind state for Cdand water exactable state for F were abnormally higher. Source tracing by Pb isotopeshowed that the pollution source in Baotou is the industry of smelting, coalcombustion and waste gas from vehicles. Inhalable particles in Hohhot wereconcentrated with F and Zn with low As, Cd, Pb, Th, Se and La concentrations, andhave similar concentrations for Hg, Ni, Co, Cr and Cu compared with those in Baotou.Soil and dust samples from the tailing dam were concentrated with Ce, La, F, Cd, Pb,Zn, Th, Y, Cu and Cr. Surface and underground water has high F and Pb. And F, Pb,Hg, Ce, La and Y are concentrated in the agricultural plant and human hair, which are harmful for human health. The radioactive elements has low concentrations and do noharm to human health. Pollution assessment for soil of Hohhot and Baotou showedthat the concentrations of Cd, Hg and Pb have exceed the limit, which has high riskfor the eco-environment and it is safe in the other areas.