Spring water quality assessment using water quality index in villages of Barwari Bala, Duhok, Kurdistan Region, Iraq

Abstract Periodic quality assessment of drinking water sources is necessary to guarantee the quality and security of water supply to people. Accordingly, this study assessed the drinking water quality of spring water of some villages located in Barwari Bala region of Duhok Governorate, Kurdistan region, Iraq, using the water quality index (WQI). To realize this objective, 120 spring water samples were collected from ten villages during the dry and wet seasons in 2018 and were analyzed for major physicochemical characteristics, including: calcium (Ca 2+ ), magnesium (Mg 2+ ), sodium (Na + ), potassium (K + ), chloride (Cl − ), sulfate (SO 4 2− ), nitrate (NO 3 − ), pH, total dissolved solids (TDS), turbidity, total hardness (TH) and total alkalinity (TA). The results for pH, turbidity, sodium, potassium, chloride, sulfate and nitrate showed that the water samples at all the sampled springs were suitable for drinking and within permissible limits based on given standards. However, TDS, TA, calcium and magnesium exceeded the permissible limits at some sites. It was also observed that, except for SO 4 2− , at almost all the sites, the majority of parameters were significantly greater during the wet season compared to the dry season. With reference to all the parameters, the WQI values ranged from 10.76 to 18.13 during the dry season and from 17.10 to 20.45 during the wet season, indicating that all water samples are classified as having “excellent” water quality for drinking purposes. The calculation of WQI based on specific parameters, where values were close to or exceeded the maximum acceptable limits, showed that the water quality status of all water samples was “good” quality, except for sites S6 and S8, which were classified as “poor” quality and are not considered suitable for drinking purposes without treatment. Water from almost all the sampled spring sites can be considered as suitable for drinking purposes, although some parameters exceed permissible limits. Simple filtration treatment of the sampled spring water before use is desirable for ensuring good quality and security of the water supply to people of these areas.