The distribution characteristics of Cd in different function area of city——Take Guiyang City as a case

Based on street dust sampling in different function area in Guiyang City,the influence of city function on Cd in dust in terms of the total Cd level and the Cd level in different size fractions of dusts in different function area was analyzed.The result showed that the average value of Cd in dusts of Guiyang was 1.28 mg/kg.The level of Cd dusts was indexed in the order of city squareschoolindustry area(residential area)traffic areacommercial area(garbage stations).The effect of city function resulted in three levels of Cd accumulation in dusts.The heavily accumulated area were city square and school area.Materials with high Cd concentrations may lead to the heavy Cd accumulated in dust there.Dusts Cd in commercial area and garbage stations were mainly enriched in fine fraction(≤105 μm) while those in city squares,school area and residential area were mainly enriched in the medium size fraction(105-250 μm).There were no significant difference in size fractions in industry and traffic area.The evidence of the least contribution from coarse fraction to Cd in dust was obvious in all function area.