Metal pollution and its impact on algae in flowing waters in India.

Metal pollution in the river Godavari in India, due to discharges of liquid wastes from a paper mill, has been studied for a period of two years. At the discharge point and 1 km from the point of discharge, iron, manganese, and zinc were recorded in high concentrations, whereas cadmium and chromium were observed in low concentrations. No metal was in detectable concentration in water before the river receives the effluents. A considerable drop in pH values and an appreciable increase in organic matter, hardness, and calcium levels were noticed after entry of wastes. Diatoms were more diversified in fresh water, whereas cyanobacteria were more prevalent both qualitatively and quantitatively at the polluted stations. Mathematical equations involving heavy metals and physicochemical factors were drawn for better understanding of the distribution of algae.