VALORISATION OF THE CONCENTRATION LEVELS OF TOXIC METAL CATIONS IN RIVER DANUBE SURFACE WATER VIA MULTICRITERIA ANALYSIS

In this research physicochemical parameters and cations of heavy metals, metalloids and light metals (Na, K, Ca, Mg, Ni, Cr, Mn, Fe, Cu, Cd, Hg, As, Pb, Zn and Al) were determined in the River Danube surface water during the five-year monitoring program. Sampling campaign was carried out from 2011 to 2015 with respect to the seasonal variations. The concentration of selected cations (Cr, Mn, Fe, Cu, Ni, Cd, Pb, Zn and Al) and four key physicochemical parameters (temperature of water, pH, dissolved oxygen and electroconductivity) on three representative locations were selected for further statistical evaluation and Environmental Risk Assessment (ERA) calculation. For the purpose of risk assessment, the indirect approach has been selected. The calculation of risk quotient using Measured Environmental Concentration and Predicted No-Effect Concentration provided through EU guidelines. The obtained results have been evaluated by multicriteria analysis using Principal Component Analysis, Cluster Analysis, presented via Cluster dendrograms and Hasse diagrams by Decision Analysis by Ranking Techniques software. Hasse diagrams were created for visualization of finite partially ordered sets of metal cations concentration levels. The results of performed statistical analysis showed the close correlation between physicochemical parameters and concentration levels of metal cations. Cluster Analysis and Hasse diagrams enabled distinction of sampling locations and the metal cations that showed the most potential risk on the entire flow of Danube River in Serbia. The obtained results of the risk assessment have shown that the metal cations pose a significant risk to the aquatic environment and human health.