Spatial distribution of the contamination and risk assessment of potentially harmful elements in the Ghizer River Basin, northern Pakistan

The Ghizer River Basin (GRB) is one of the sub-basins of the Indus River hosting rich mineralization and agrogenic activities. The GRB was sampled for 55 water samples and investigated for potentially harmful element (PHE) concentrations using inductively coupled plasma mass spectrometry. PHE concentrations in the water samples of the GRB were used to calculate the potential of non-cancer risks such as chronic daily intake (CDI) hazard quotient (HQ) and cancer risk (CR). The highest average concentrations of chromium (37.1 +/- 17.1 mu g/L) copper (27.4 +/- 12.5 mu g/L) arsenic (4.8 +/- 0.9 mu g/L) cobalt (9.2 +/- 3.3 mu g/L) and nickel (62.7 +/- 27.6 mu g/L) were noted for the Ishkomen River segment of the GRB. Similarly manganese (417 +/- 144 mu g/L) cadmium (1.95 +/- 0.02 mu g/L) lead (7.7 +/- 1.4 mu g/L) and zinc (28.4 +/- 5.5 mu g/L) concentrations were maximum at downstream of the GRB. Geospatial and statistical analyses showed that lithogenic sources contributed higher to PHE contamination in the water of the GRB than the agrogenic sources. PHE concentrations were noted under the World Health Organization (WHO) drinking water thresholds#except for nickel. Results showed the uppermost CDI value of 13.6 mu g/kg-day for manganese and HQ value of 0.52 for arsenic via water intake of children. Non-cancer and CR values through water intake were under the US Environmental Protection Agency (USEPA) thresholds and noted as suitable for drinking and other domestic purposes.