Determination of lethal range and the median lethal concentration (LC50 96h) of Paraquat on Benny fish ( Mesopotamichthys sharpeyi )

In this study, acute toxicity of Paraquat was studied on
Mesopotamichthys sharpeyi fingerling. The acute toxicity test was performed in static renewal system based in the standard method proposed by OECD during 96 h, physicochemical parameters of water including pH, dissolved oxygen and Temperature were monitored. In order to determine the lethal range of paraquat a range finding test was carried out. The acute toxicity test was preformed in 5 treatments in triplicates. The obtained data were analyzed by using Probit analysis with 0.05 confidence limit. According to the results of this study, 24 h LC50, 48 h LC50, 72 h LC50 and 96 h LC50 of paraquat on Mesopotamichthys sharpeyi was 6.84, 5.29, 2.57 and 1.49 mg/l respectively. The Maximum acceptable toxicant concentration (MATC) of paraquat on Mesopotamichthys sharpeyi was 0.14 mg/l and the lowest was observed effect concentration witch is equal to 96 h LC50 was 1.05 mg/l. in addition paraquat lethal toxicity takes place in a narrow range of toxicant concentration.