Geochemical profile and source identification of surface and groundwater pollution of District Chitral, Northern Pakistan

Abstract

This study investigated the physicochemical parameters of the ground and surface water of district Chitral, northern Pakistan, with particular emphasis on the fate, source distribution and hydrogeochemistry. To better understand the ground and surface water hydrogeochemical profile, groundwater (n = 39) and surface water (n = 22) were collected from Asheriat and Drosh regions of the study area. The range of pH, Temperature, EC, TDS, TSS, Turbidity, Salinity, in the groundwater and surface water were ((6.3–7.6, 14.5–20.5 °C, 440–690 μS/cm, 255–438 mg/L, 2–21 mg/L, 3.9–15.7 NTU, and 0.1–0.5)) and ((6.4–7.7, 15.5–23 °C, 447–708 μS/cm, 277–445 mg/L, 5–76 mg/L, 4.7–19.3 NTU, 0.1–0.6)) respectively. Similarly the chemical parameters Cl, NO3, SO4, PO4, HCO3, Na, K, Ca and Mg were ((50–120, 17.5–75, 65–138, 11–45, 255–453, 19.5–157, 4–14, 25–140 and 16.5–51) mg/L and ((65–110, 15.5–53, 82.5–142.5, 4.5–24.5, 250–375, 23–128, 4.5–12.5, 37–140 and 15–42.5)) mg/L respectively. This study shows that EC, TSS, Turbidity, NO3, PO4, Ca and Mg exceeded the WHO's guideline values. The correlation coefficient (r) value of Na was significantly positive correlated with, HCO3 and K, and inversely related with NO3, Ca and Mg. The hydrogeochemistry of groundwater reveals more contamination than surface water because of the water rock interaction and minerals dissolution. Whereas, the surface water showed dilution due to surface recharge from river Chitral and surrounding tributaries. The groundwater and surface water shows similar cationic and anionic concentrations trend across the entire study area increased in the following order: Na > Ca > Mg > K and HCO3 > SO4 > Cl > NO3 > PO4 respectively. Chadha diagram revealed that the dominant water type of the area were NaHCO3, and CaHCO3 type. The PCA and Gibb's results of groundwater and surface water quality showed the influences of the weathering of rocks and dissolution of minerals.