GROUNDWATER QUALITY IN THE MAJOR INDUSTRIAL-AREA OF THESSALONIKI, GREECE .1. CHEMICAL COMPOSITION-GEOCHEMICAL PROCESSES

The chemical characteristics of groundwaters of the area located N-NW of Thessaloniki, Greece, are presented. Groundwater samples were colle cted from 22 wells, during the period Spring 1989-Autumn 1990. Tempera ture, pH, alkalinity and dissolved oxygen measurements were conducted in the field, while determinations of Ca2+, Mg2+, Na+,K+, Cl- NO3-, NO 2-, PO43-, HCO3-, SO42-, were performed in the laboratory. Significant variation in groundwater composition was found among the wells examin ed. Equilibrium studies of groundwater chemistry indicated that waters are mainly of ''bicarbonate'' and ''chloride'' type. All groundwater samples examined were found to be saturated or oversaturated with resp ect to calcite or dolomite. Ionic ratios showed possible inflow of sal ine water.