Hydrogeochemical characterization and water quality assessment of springs in the Emirdağ (Afyonkarahisar) basin, Turkey

Abstract

The investigation area includes the Emirdag (Afyonkarahisar) basin and its vicinity located in the Upper Sakarya section of Central Anatolia Region. Mesozoic aged recrystallized limestone and dolomites forming the basis of the investigation area, Cretaceous ophiolites, Neogene aged pyroclastic rocks, and unconstructed terrestrial clastics are the dominant rocks. There are many natural water springs in this region. Springs are the primary source for drinking and household needs. Besides, these springs are used for agricultural irrigation, trout plant, etc. In this study, a total of 10 spring samples collected from the Emirdag basin and waters were evaluated for hydrochemical processes, drinking water chemistry, and irrigation water quality. Generally, the yield of water springs which are discharged from volcanic rocks and limestones varies between 0.02 and 2.00 l/s. The pH, temperatures, electrical conductivity, total dissolved solids, and redox potential are changed between 6.53 and 7.86, 11.50 and 17.80 °C, 251 and 790 μS/cm, 132 and 490 mg/l, and 204.10 and 262.30 mV, respectively. The major ion sequence of waters is generally Ca2+ > Mg2+ > Na+ > K+ and HCO3− > SO42− > Cl− > F− > PO43−. Ca2+, Mg2+, and HCO3− are the dominant ions in the groundwater of the study area. The hydrochemical facies of the majority of the study area spring samples are “CaMgHCO3” and “CaMgSO4” types. The distribution of sample points in the Gibbs diagram suggests a rock dominance area. The Schoeller drinkability diagram shows very good and good quality waters. The springs’ suitability for irrigation classification suggests that more than 90% of the water sampling locations are suitable for irrigation. However, the water quality of Pinarbasi spring is different from the other springs due to the high electrical conductivity value (790 μS/cm). Also, the Wilcox and US Salinity Laboratory diagrams show that groundwater samples are good for irrigation. As a result of the analysis of nitrogen compounds, nitrate concentration in the Agzioren (64.09 mg/l) and Ufukpinar (62.01 mg/l) springs only exceeds drinking water standards. It is thought that the increase of nitrate in these springs is due to agricultural pollution. The values in the isotopic composition are above the local and global meteoric water lines, probably indicating similarity in the mechanism of recharge, and the tritium level shows recent groundwater contribution. The springs generally are represented as shallow and have fast circulation.