Experiments were conducted on Tilapia mosambica, Perna viridis and Villorita cyprinoides on the uptake and loss of Hg, Cd and Pb in various tissues of these organisms. Hg was found to be highly toxic to the clams as compared to the fish and mussels. Pb was found to be the least toxic. Hg was found to accumulate in greater amounts as compared to Cd and Pb. Preferential accumulation and subsequent retention was observed for each metal to particular tissue, thus Hg showed affinity towards muscles, Cd towards liver and Pb towards gills. Similar trends of distribution were oberved in tissues of fishes collected from the Indian coast except that Pb showed affinity towards gills as well as kidney. The rate and degree of depuration varied for different metals. The metal concentrations found in the tissues of these organisms reflect the external concentrations, makes them ideal tools for monitoring environmental levels