Evaluating hydrogeochemistry and turbidity problem of a carbonate aquifer, Shiraz, Iran

Important karstic aquifers exist in west and southwest of Iran. Mansour-Abad Karstic region is located in Shiraz, southwest of Iran. It supplies the drinking water for the whole area by 4 pumping water wells, some of which have water turbidity problem. The present research aims to assess the hydrogeochemistry and turbidity problem in the karstic water production wells. The EC varies between 703 (in well No.1) and 1096 µmohs/cm (in well No.4). All water wells have similar ion concentration trend, indicating the same origin. The dissolution of gypsum during dedolomitization process induces the transformation of dolomite to calcite in the study area, especially in well No.4. The concentrations of most trace elements in the study area are lower than the standard value. Bacteriological water parameters are outside the accepted limits recommended by WHO for drinking water. Wells No. 1, 2 and 3 have turbidity values greater than limited values for drinking water which is about 5 TU; therefore, only well No.4 is used as drinking water resource in the study area. Most probably, interference of clay mineral layers with groundwater flow is one of the main causes of turbidity in some wells.