Toxicological effects of mercury on a freshwater fish, Anabas scandens, Cuv. & Val. and their ecological implications

• Published in: Environmental pollution 1978-01, Vol.16 (1), p.31-39
• Main Authors: Panigrahi, A.K., Misra, B.N.
• Format: Article
• Language: English
• Subjects: environmental science; natural resource management; pollution
• ISSN: 0013-9327
• DOI: 10.1016/0013-9327(78)90135-0

Fish, Anabas scandens Cuv. & Val., exposed to mercuric nitrate all died in concentrations greater than 5 mg l −1. However, at 3 mg l −1 they survived although they showed a variety of pathological and biochemical disorders. The main clinical symptoms such as inappetence and ataxia appeared after 5 days' exposure. After 3 weeks' exposure, blindness was noted in 29% of the fish and respiratory rate was considerably reduced. After 4 weeks a total of 71% of fish had become blind. Partial recovery of respiratory rate occurred in all treated fish when they were transferred to fresh, mercury-free water. Considerable reductions in haemoglobin percentage, red blood cell (RBC) count, body weight and protein content of the treated fish were observed. The mean concentration of mercury in the liver of the fish exposed for a period of 45 days was as high as 3·0 ± 0·16 μg g −1 wet tissue and in the muscles 2·8 ± 0·18 μg g −1 wet tissue, while concentrations in untreated liver and muscle were 0·20 ± 0·05 and 0·12 ± 0·05 μg g −1 wet tissue, respectively. The physiological and biochemical disorders were related to the concentrations of mercury in the tissue. Mercury accumulation in algae and Hydrilla plants was 0·76 ± 0·022 and 0·83 ± 0·035 μg g −1 wet weight, respectively within a period of 45 days' exposure.