Acute toxicity of Nuvan, an organophosphate to freshwater fish Ctenopharyngodon idella and its effect on oxygen consumption.

The acute toxicity of Nuvan to the grass carp Ctenopharyngodon idella was determined using static and continuous flow through system for 24, 48, 72 and 96 hr. The median lethal concentration (LC50) values were 13.1, 10.9, 9.8 and 6.5 mg l(-1) respectively in static system and 10.7, 9.5, 8.0 and 7.5 mg l(-1) respectively in continuous flow through system. A reduction in oxygen consumption is observed when the fish is exposed to the toxicant and the mortality is due to effect of metabolism of energy synthesis.