Assessment of as and metallic element contamination of riverine sediments from Yangtze river in nanjing reach, China

In order to investigate contamination status and to assess potential ecological risks of metal(loid)s in aquatic environment resulting from the rapid industrialization and the urbanization, metal(loid)s (Cd, Cr, Cu, Ni, Pb, Zn and As) in riverine sediments from the Yangtze River in Nanjing reach were analyzed. Contents of those metal(loid)s were 22.9-64.1 mg kg^-1 for Cu, 27.9-230 mg kg^-1 for Pb, 79.2-258 mg kg^-1 for Zn, 0.85-4.50 mg kg^-1 for Cd, 20.9-89.5 mg kg^-1 for As, 28.8-49.5 mg kg^-1 for Ni, and 65.5-93.2 mg kg^-1 for Cr, respectively. Results from modified BCR sequential extraction indicated the different sediment phase partitioning of metallic elements. A significant correlation was found between Cu, Cr and Ni, Pb and Zn, Cd and As (p<0.01) by Pearson correlations analysis. Three principal components accounted for 90.4% of the total variance were identified for sediment samples by using principal component analysis, indicating different pollution sources. Results from enrichment factor values and factor analysis confirmed that Cd and As were the main anthropogenic loads and had similar contamination source. Potential ecological risk index indicated the ecological risks posed by Cd and As in the sediments. Therefore, combination of multi-methods can obtain more information on metal(loid) pollution in riverine sediments of urban reach.