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 i n Seoul Metropolitan City and were examined for spatial and temporal variat ion of heavy metal composition (Cr, Cu, Zn,Pb, Cd and As). Samples for anal ysis were treated with 0.1 N HCl for partial extraction and with mixed stro ng acid (HF + HNO3 + HClO4) for total extraction: Using the normalization o f the acid extractable metal concentrations with aluminum (element/Al), two statistical approaches, i.e., two-way ANOVA test and R-mode factor analysi s (FA), were performed to examine the major sources of variability in the h eavy metal composition. The FA results show that Pb and Cr are strongly dep endent on site-specific traffic density, whereas Cu. Cd and Zn vary with si te characterization (especially the percentage of metal industry) as well a s 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 sediment s have to be guided by appropriate environmental measures.