ORGANOTOXICITY OF CADMIUM CHLORIDE ON THE FRESH WATER FISH LABEO ROHITA
*Pawlin Vasanthi Joseph and Nithya R.
Toxicity is a measure of the degree to which something is toxic or poisonous. Several toxic substances entering into aquatic organisms daily may be very small and therefore, often no apparent or sudden effects are noticeable. However, this may result into impairment of many vital functions thus gradually affecting fish population indirectly. Cadmium is a rare element and is usually found as an impurity in ores of other metals principally those of zinc. The present study aims to determine the effects of sub chronic exposure of inorganic cadmium in the inland fish Labeo rohita by observing the histopathological changes in the vital organs like gills, liver and kidney. The LC50 at 96 hrs was determined by the Probit analysis method. The experiment was designed to expose the fish to different concentrations of cadmium chloride - 500μg/l, 700μg/l, and 900μg/l. One trough served as the control. Destruction to the gills is observed in certain areas. Pronounced changes like fusion of lamellae were observed. Severe damage and marked proliferation were seen in the liver. In the kidney a reduction in the size of the epithelial cells lining the tubules was found. The study can be considered as a good bio-marker to access the health status of fishes as well as the worsening status of aquatic bodies in relation to metallic contaminants particularly cadmium.
Keywords: toxicity, cadmium, histopathology, proliferation, sub-chronic exposure, LC50 Contaminants.
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