A new approach to analysis of accumulation and enrichment of heavy metals in Danube River sediment along the Iron Gate reservoir in Serbia

Concentrations of heavy metals (Cu, Zn, Pb, Cd) and long-lived radionuclides (U, Th, Cs) along the Iron Gate reservoir of the River Danube in Serbia were determined. In years 2005-2009, water and sediments were sampled at six sites along 200 km of the River Danube from Belgrade to Đerdap (Iron Gate) hydroelectric power plant. The concentrations of heavy metals in sediment were found to be in the intervals: 27.9-149.3 mg kg-1 for Cu, 55.2-228.4 mg kg-1 for Zn, 13.5-71.6 mg kg-1 for Pb , 0.3-25.2 mg kg-1 for Cd, and 4.0-17.5 Bq l-1 for 137Cs. These values are in correlation with concentrations in river water when expressed by the equilibrium coefficients (Kd) between solid and liquid phases. The behaviors of heavy metals were evaluated by applying models for the prediction of pollutants’ behavior in rivers. The fluxes of heavy metals from water to sediment and vice versa were also determined