Analysis of arsenic bioaccumulation in different organs of the nutritionally important catfish, Clarias batrachus (L.) exposed to the trivalent arsenic salt, sodium arsenite.

Pattern of arsenic bioaccumulation in six organ systems (blood, brain, gills, liver, muscles and skin) of Clarias batrachus was analysed following exposure to sublethal (1 mg L(-1); 5% of 96 h LC(50) value) concentration of sodium arsenite. After 60 days of treatment the liver accumulated highest concentration (9.711 ± 0.138 μg g(-1) dry wt of tissue.) of arsenic followed by gills (6.156 ± 0.154) > blood (6.070 ± 0.043) > muscles (5.756 ± 0.123) > skin (5.606 ± 0.140) > brain (2.350 ± 0.205). The bioaccumulations of arsenic in all the tissues were time dependant and increased with exposure period. Although the exposed fish loaded with arsenic did not die after prolonged treatment (60 days), the amount of arsenic accumulated made them unsuitable for human consumption. Due to depletion of the proteineous components of their muscles, the body mass of the exposed fish decreased without corresponding decrease in their length. This made the fish lean and thin. These proteineous moieties of the muscles and other tissue systems of the stressed fish were mobilized for breakdown to generate additional requirement of energy to combat the arsenic toxicity.