Assessment of acute and chronic toxicity of sodium cyanide on some Egyptian freshwater fishes [electronic resource].

Includes reference.

Fifty Clarias gariepinus and fifty Oreochromis niloticus were used in this study to determine the acute and chronic toxic effects of sodium cyanide in both species. The results revealed that the acute lethal concentration dose (Lc50\96hrs) for sodium cyanide was 2 mg\L for Clarias gariepinus with weight range (80-120gm) and 10 mg\L for Oreochromis niloticus with weight range (60-100gm). The results of clinical abnormalities and abnormal behavioral changes during short term and long term exposure to sodium cyanide were observed and the mortality patterns were recorded. The main clinical abnormalities observed including intermittent periods of nervousness and rest- ness, surfacing and moving upside down, signs of asphyxia, erection of barbells and later the fish appeared anaesthetized during the periods of rest-ness. The characteristic post mortem findings was observed in both species studied and the main findings including rosy red coloration of gills and accessory lungs, severe congestion of the heart, congestion of internal organs, hemorrhages in the brain in both species. Also the results of macroscopical and microscopical examination of specimens from gills, liver, brain, kidney, stomach, muscles and intestine of both Clarias gariepinus and Oreochromis niloticus exposed to sodium cyanide were determined.

Summary in Arabic.

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