QUALITY ASSESSMENT OF SURFACE WATER AT THE BASIN OF STRYMONAS RIVER, NORTHERN GREECE

This study presents the water quality assessment of Strymonas River, Northern of Greece. Strymonas River is a transboundary river affected by various agricultural, industrial and urban activities. Moreover, in the basin of this river there are sites which are included into the EU 'Natura 2000' network due to their ecological significance. Physicochemical parameters (T, pH, EC, DO, TDS), nutrients (NO2-, NO3-, NH4+, PO4-3), major ions (Cl-, Na+, K+, Mg+2, Ca+2) and metals (Fe, Cu, Zn, Mn), in total 24 parameters, were determined monthly at sixteen monitoring sites along the river and its main tributaries, as well as in wastewaters from main point sources (sewage effluents, dairy industry) discharged into the river. A full chemometric approach including Factor Analysis, Cluster Analysis and Discriminant Analysis combined with the Nemerow pollution index were employed for an overall water quality assessment, within the framework of European Water Directive 2000/60/EC. Information regarding temporal and spatial variation of measured parameters, water quality status of the river basin and main tributaries, most impacted sites, possible pollution sources and crucial parameters that further have to be monitored, were extracted. Based on this, a network of selected sites can be established for monitoring of those parameters (DO, Na+, NO3-, PO4-3, NO2- and NH4+) that can be better describe the water quality and variations in Strymonas River.