Statistical Analysis of Heavy Metals Concentration in Water and Sediments in the Lower Part of the Danube River - Romanian Section

The Danube River is a transboundary water body traversing many populated areas along its course and therefore is highly vulnerable to heavy metal pollution due to urbanization and industrialization. In this study, sixteen sites were sampled along the Danube River between Km 347 and Km 182 during September 2012 - August 2014 for assessment of heavy metal pollution status. Water and bottom sediment samples were collected monthly from left and right bank of the Danube and were determined the temperature, the pH and four heavy metals: Cu, Cr, Ni and Zn, by AAS technique. Total metals concentrations of water ranged between 0.05-13.63 mu g/L for Cr, 0.41-49.84 mu g/L for Cu, 0.02-32.0 mu g/L for Ni and 0.20-93.50 mu g/L for Zn. Meanwhile, for sediment, it ranged between 23.53-46.64 mg/kg for Cr, 21.02-42.35 mg/kg for Cu, 26.23-38.47 mg/kg for Ni and 78.66-106.22 mg/kg for Zn. These data revealed that metal concentration levels in the sediments surpassed corresponding levels in flowing water. To complete the monitoring process, statistical analyses were performed using software packae Minitab 16 and JMP 9 (SAS). Pearson correlation coefficient revealed a strong relationship between Cr-Ni (0.881), Cu-Ni (0.879) and Cr-Cu (0.829) for water samples and Cu-Zn (0.772) for sediments.