Toxicological Effects in Fresh Water Teleost Fish Heteropneustes Fossilis Induced By Cadmium

Abstract

Among several elements of the periodic table, there are 35 metals are associated with community and occupational exposure. Out of these, 23 are described as heavy metals. These elements are generally released in small amounts into the environment by processes like weathering of rocks, volcanic eruptions etc. and their intake/exposure is necessary in trace amounts for good health. But, presently, there is a steady increase in their concentration in all habitats owing to mining, electroplating, paints and dye, battery making industries etc. The release is rapid with the rapidly growing technology and heavy metal application in these industries. The two most important factors that contribute to the deleterious effects of heavy metals as pollutants are their indestructible nature through bioremediation unlike organic pollutants and their tendency to accumulate in environment especially in the bottom sediments of aquatic habitats in association with organic and inorganic matter. Cadmium (Cd), one of the heavy metal toxicants, is widely used in Ni-Cd batteries manufacture, metal and mining industry, dentistry etc. because of its non- corrosive nature. Cd is released in considerable amounts through industrial effluents into soil, surface and ground water systems. These excess amounts in addition to newline newlinenaturally occurring levels gradually build up to toxic levels causing damage to the biota of the aquatic ecosystem. It shows biomagnifications and has greater half-life periods. Cd was found to interfere with many protein and carbohydrate metabolisms by inhibiting the enzymes involved in the processes. Toxicity of Cdto fishes has stimulated considerable interest in recent years. Studies have shown that other heavy metals, vitamins, chelating agents and protein diets which also can alter the physiological, biochemical and behavioral aspects is fish. In the present study the effect of Cd on the morphology, behavior, histopathology and biochemical parameters of different tissues of the fresh water fish Heteropneustes fossilis