Ecological and health risk assessment of heavy metals bioaccumulation in Ganges fish near Varanasi, India

Abstract

Abstract Heavy metal contamination in river Ganga is one of the factor for deterioration in its water quality, also adds to human health risks. We designed our study to achieve a holistic approach by not only estimating the concentration of heavy metals (Lead, Manganese, Chromium and Cadmium) in the river water at different sites based on human anthropogenic activities but also in the fishes residing in the same sites that are collected for human consumption on daily basis. We found, Ganga river in Varanasi is highly loaded with metals (PLI = 6.698) Mean concentration in water was: Pb 1.29 mg/L, Mn 1.325 mg/L, Cr 0.169 mg/L and Cd 0.161mg/L, which were above the permissible limits stated by Environment Protection Agency (EPA) in drinking water. Fishes including exotic and invasive species were collected from the wild and were processed for the presence of these metals in their living tissues. Degree of heavy metal concentration followed liver > gills > muscles. Highest accumulation of Pb was observed in Carpio (Cyprinus carpio) liver (8.86 µg/g) and lowest in Baikari (Clupisoma garua) muscles (0.07 µg/g). Total Target Hazard Quotient (THQ) value i.e. hazard index (HI) showed values in following sequence: C.carpio > O. nilotus > C.punctatus > J.coitor > M.armatus > M.tengara > Baikari. Maximum HI was recorded in Carpio, which is highly consumed fish by human, hence may be harmful to them.