Distribution of heavy metals (Cr, Cu, Zn, Pb, Cd, As) in roadside sediments, Seoul Metropolitan City, Korea

Urban roadside sediments were collected for five months from eleven sites in Seoul Metropolitan City and were examined for spatial and temporal variation of heavy metal composition (Cr, Cu, Zn,Pb, Cd and As). Samples for analysis were treated with 0.1 N HCl for partial extraction and with mixed strong acid (HF + HNO3 + HClO4) for total extraction: Using the normalization of the acid extractable metal concentrations with aluminum (element/Al), two statistical approaches, i.e., two-way ANOVA test and R-mode factor analysis (FA), were performed to examine the major sources of variability in the heavy metal composition. The FA results show that Pb and Cr are strongly dependent on site-specific traffic density, whereas Cu. Cd and Zn vary with site characterization (especially the percentage of metal industry) as well as the temporal amount of precipitation. Arsenic. however, does not show any distinct change. As the roadside sediments are heavily polluted with heavy metals (especially Zn and Cu), the management and disposal of the sediments have to be guided by appropriate environmental measures.