Heavy metals concentrations and risk assessment in the sediment of Ganga River between Kanpur and Prayagraj, UP, India

This study analyses the heavy metal contamination in freshly deposited sediment of 210 km stretch of River Ganga between Kanpur and Prayagraj, Uttar Pradesh (U.P.), India. As per APHA (2012)30 digested samples were prepared after collecting from 10 sampling sites. Then the samples were analyzed for 8 heavy metals namely Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), and Zinc (Zn) by Atomic Absorption Spectroscopy (AAS) (Shimadzu AA-6300). Risk assessment was done by employing four pollution indices. The average values of contamination factor (CF) indicate that the level of contamination by Pb is moderate (1 < CF < 3) and significant by Cd (3 < CF < 6). Whereas, the average value of Geo-accumulation index (Igeo) indicates that the sediments are uncontaminated or in a moderate level of contamination by Pb (0 < Igeo < 1) and in a moderate level of contamination by Cd (1 < Igeo < 2), which may have harmful effects on Ganga River ecology. The values of Pollution load index (PLI) indicate that the Ganga River sediment has a low level of contamination. Based on various pollution indicators, it has been observed that concentrations of Cd and Pb in the river sediment is a matter of concern and may lead to further deterioration of sediment quality in near future due to increasing anthropogenic activities in the river basin, hence proper management strategies should be taken to control the direct dumping of both domestic and industrial wastewater in the river.