Spatial distribution of contaminants and water quality assessment using an indexical approach, Astore River basin, Western Himalayas, Northern Pakistan

Astore River is an important tributary located in the Upper Indus River Basin, Western Himalayas, Northern Pakistan. This study aimed at assessing water quality of the river for domestic, drinking, and irrigation purposes. Astore river (n = 40) samples were collected and analyzed for a set of 17 physicochemical parameters. Water quality index (WQI), corrosion, scaling tendencies, and irrigation water quality indices were used for its grading and statistical analyses for the source apportionment of contaminants. Results indicated that turbidity, fluoride, and nitrate (NO3) values surpassed the safe limits in 60%, 2.5%, and 2.5% of samples. WQI revealed that only 19.5% of samples were classified in poor and very poor water quality classes due to turbidity and NO3. Irrigation and corrosion indices of the river showed its suitability for agriculture and corrosive tendency. The dominant hydro-chemical facies were Ca-Mg/Cl-SO4 and results suggested that natural sources play a role in shaping hydrochemistry.