Determination of lethal range and median lethal concentration (LC50 96h) values of diazinon on Caspian Sea common bream (Abramis brama)

Abstract

Pesticides are environmental contaminants which normally enter to aquatic ecosystems after being used in aquaculture. In this research, acute toxicity of diazinon was studied on Caspian Sea common bream (Abramis brama). This pesticide may enter in aquatic food chain and cause serious problems for aquatic organisms as well as human. The acute toxicity test was performed during 96h in static renewal system based on the standard method proposed by OECD. A range finding test was carried out in aquariums containing 10L of test solution to determine the lethal range of diazinon on fish. The acute toxicity test was then preformed in 5 treatments and 3 triplicates for each treatment. Obtained data were analyzed using probit analysis with %5 confidence limit. According to the results, LC_50 24h, LC_50 48h, LC_50 72h and LC_50 96h of diazinon on Caspian Sea common bream was 10.974, 10.391, 9.134 and 7.316 respectively. The maximum acceptable toxicant concentration (MATC) of diazinon on Caspian Sea common bream was 0.073 mg/l and the lowest observed effect concentration which is equal to LC_50 96h was 2.63 mg/l. According to the results and comparing with other studies, it can be discussed that Caspian Sea common bream is more resistant against diazinon rather than other fish species. In addition, lethal toxicity of diazinon takes place in a moderate range of toxicant concentrations.