Metal distribution in the sediments, water and naturally occurring macrophytes in the river Gomti, Lucknow, Uttar Pradesh, India

River Gomti receives treated/untreated industrial as well as municipal wastes from various drains of Lucknow city, India. In order to study heavy metal pollution (Cd, As, Pb and Cu) in the river, water and sediment samples were collected from 10 sampling stations along a 9 km stretch in the city of Lucknow. Results revealed that the concentrations of heavy metals in water samples were in the range: As: 0.035-0.061, Cd: 0.016-0.068, Cu: 0.029-0.062 and Pb: 0.031-0.065 mg l(-1) whereas in sediments metal concentrations were found to be As: 3.72-14.98, Cd: 1.91-8.39, Cu: 8.97-95.35 and 35.82-90.92. mu g(-1). Bioaccumulation of these metals was assessed in four aquatic macrophytes, viz. Pistia stratiotes, Eichhornia crassipes, Polygonum coccineum and Marsilea quadrifolia. Pistia stratiotes and Polygonum coccineum accumulated maximum amount of Pb followed by Cu, Cd and As, whereas in the case of Eichhornia crassipes and Marsilea quadrifolia the relative metal accumulation pattern was found as Cu > Cd > Pb > As and Cu > Pb > Cd > As respectively. The present study suggests that though the concentrations of toxic metals were lower in water, chronic exposure could result in bioaccumulation to a degree many-fold higher than in growing medium. It was also concluded that the water and sediment of the river should be regularly monitored for heavy metal contamination and care should be taken while using river water in agriculture/aquaculture.