Hydrogeochemical investigation of groundwaters of Altınekin (konya) basin

In this study, the hydrogeochemical properties of the groundwater in the Altinekin (Konya) basin are evaluated and its suitability as irrigation water is investigated. For this purpose, groundwater samples were collected from 40 drilling wells in the study area during the dry and wet periods. Temperature, pH, total dissolved solids (TDS) and electrical conductivity (EC) values of the samples were determined in situ, and major ion analyses were performed. The pH values of the samples were 7.30 and 7.25 in the dry and wet periods respectively, indicating a slightly alkaline nature. The average values of TDS and hardness (TH) were 1241 and 1249 mg/l and 779 and 805 mg/l, respectively, for both the dry and the wet periods. The majority of the samples in both periods were classified as "very hard-fresh water" to "very hard-brackish water". The groundwater samples are of the mixed, Na-Mg-Cl and mainly Ca-Mg-HCO3. The results of the chemical analyses showed that water-rock interaction is one of the main processes affecting groundwater chemistry and that evaporation also has an effect on the chemistry of samples A3, A7, A28 and A31. Dissolution and/or weathering of carbonate rocks, which are common in the study area, is one of the main processes affecting groundwater chemistry. Another important process affecting groundwater chemistry is the dissolution of evaporitic minerals. In addition, ion-exchange reactions, which are more pronounced during the rainy period, are an important process affecting groundwater chemistry. Of the parameters used to assess the suitability of groundwater in the study area for use as agricultural irrigation water, 5 samples were found to be unsuitable for use as irrigation water in terms of EC values, 10 samples in terms of Magnesium Hazard (MH) index, 1 sample in terms of Kelley Index (KI) and 14 samples in terms of Potential Salinity (PS). Furthermore, according to Wilcox and US Salinity Laboratory Diagrams, samples A3, A7, A28, A29 and A31 are "unsuitable" for irrigation water. NO3 concentrations of groundwater samples ranged from 4.65 to 970.8 mg/l with an average of 79.48 mg/l in the dry season and from 5.23 to 981.2 mg/l with an average of 105.2 mg/l in the wet season. In the dry period, 45% of the samples and in the wet period, 50% of the samples exceeded the limit value of 50 mg/l permitted by the WHO and TSE-266, and NO3 concentrations reached high concentrations around residential areas as well as in agricultural areas. The results show that NO3 pollution in the groundwater was not only caused by agricultural activities, but also by sewage leakage, septic tank leakage, landfill leachate and domestic and livestock waste, especially in and around residential areas. According to all the results obtained in this study, it can be said that the NO3 pollution in the study area has reached a serious level and is likely to increase further if no measures are taken.