Spatial distribution of heavy metal and risk indices of water and sediments in the Kunhar River and its tributaries

The present study investigated heavy metal (HM) concentrations in water and sediment of the Kunhar River and its tributaries in Kaghan valley, Northern Pakistan. The highest mean concentration was observed for iron (Fe) 316 +/- 47.4 mu g/L and the lowest for cadmium (Cd) 2.45 +/- 0.31 mu g/L in the upstream water of this study. The highest mean hazard quotient value of 0.43 was calculated for children through downstream water consumption. The concentration of HM in water was used for the calculation of HM pollution index and HM evaluation index , showing a low level of contamination. The highest mean sediment concentration was found for Fe was 35500 +/- 2700 mg/L and the lowest for Cd was 1.96 +/- 0.23 mg/L in upstream of Kunhar River. Pollution quantification factors values were the highest downstream. Statistical analyses revealed that water and sediment contamination of Kunhar River and its tributaries was mainly attributed to geogenic sources.

Automated summary

The study found higher concentrations of heavy metals in the water and sediment of the Kunhar River and its tributaries, especially iron. The pollution levels of heavy metals in the water were relatively low, mainly attributed to geogenic sources.