Toxicity of cadmium on the biochemical composition and histology of estuarine clam meretrix casta

The toxic effect of the heavy metal cadmium on the biochemical constituents and histology of digestive gland clam Meretrix casta was studied. The clam were exposed for 10, 20 and 30 days in 10% sub lethal concentration of 96 hr LC50 of cadmium (1.25 mg/l). There is significant decrease in the carbohydrate, protein and lipid profiles in the digestive gland and gill after exposed to sublethal concentration of cadmium. In clam exposed to sub lethal concentration of cadmium various histopathological alterations are observed after 10 days of exposure. Shrunken of digestive and secretory cells and enlarged lumen were noticed. At 20 days of exposure, rupturing of cell membrane and degeneration of digestive tubules were also observed. After 30 days of treatment, the hepatopancreas was highly damaged vacuolization, necrosis and atrophy of digestive cells were also observed.