SKŁAD CHEMICZNY WÓD PODZIEMNYCH WĘGLANOWEGO KOMPLEKSU WODONOŚNEGO TRIASU W REJONIE UJĘCIA BIBIELA W ŚWIETLE BADAŃ MODELOWYCH

Abstract

GROUNDWATER CHEMISTRY OF THE TRIASSIC CARBONATE AQUIFER IN THE BIBIELA WELL FIELD AREA IN VIEW OF GEOCHEMICAL MODELLING

The Bibiela well field is one of the biggest intakes in the Upper Silesian region, extracting groundwater from the Triassic carbonate aquifer. The paper describes groundwater chemistry based on over 5000 chemical analyses of water from 22 wells from the years of 1956–2009. Saturation conditions of water with respect to calcite, dolomite and gypsum were calculated by means of AquaChem software combined with Phreeqc. Chemical composition of considered groundwater shows spatial and temporal variability mostly due to complicated geology. Intensive groundwater exploitation caused water table lowering of about 70 m, what changed hydrogeochemical conditions and caused some processes to happen or intensify. The most probable process is calcite and dolomite dissolution but also dedolomitization due to inflow of water enriched with SO4 and Ca ions from the dissolution of gypsum.