Calcutta Pollutants: Part 1: Appraisal of Some Heavy Metals in Calcutta City Sewage and Sludge in Use for Fisheries and Agriculture

Abstract
A chelate extraction procedure followed by atomic absorption spectrometry (AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described for the determination of some heavy metals (Pb, Cu, Zn, Cd, Ni, Co, Mn, Fe and Cr) in sewage and sludge. The procedure is applied to the determination of Calcutta sewage and sludge. The concentration of the above-mentioned heavy metals in Calcutta sewage-sludge is lower in magnitude when compared with that of some cities in other countries.