International Conference on Advances in Environment and Bio-Technology - EBT 2014
Author(s) : DAN SHANG , LORETTA Y. LI , NI ZHAO , RANRAN LI , XINWEI LU
Concentrations of Cd, Cr, Co, Mn, Ni, Pb and Zn in urban dust samples from different functional areas of a medium-size city in China were determined by atomic absorption spectrophotometry. The speciation of these heavy metals was determined by the three-stage sequential extraction procedure suggested by European Community Bureau of Reference (BCR), and their environmental risks were evaluated based on the potential ecological risk index method. The results show that the concentrations of Cd, Co, Ni, Pb and Zn in the dust, but not Cr or Mn, are higher than their corresponding background values of local soil. The analyzed heavy metals in the dusts from different urban functional areas presented distinct accumulation. Speciation analysis results indicate that Cd and Zn were mainly in acid soluble form (45.1% and 36.1% respectively); Pb was mainly in reducible form (53.9%); Co and Cr were mainly in the form of residual state (43.1% and 65.6%, respectively); Mn was mainly in the residual state and oxidizable form (33.4% and 29.8%, respectively), whereas Ni was mainly in oxidizable and residual form (36.1% and 35.2%, respectively). Cd presented considerable ecological risk to very high ecological risk in the dusts, while the other metals examined presented low ecological risk. The total ecological risks of all analyzed metals in the dust corresponded to high ecological risk.