Determination of median lethal concentration of herbicide Bensulfuron methyl in common carp (Cyprinus carpio)

Bensulfuron methyl is one of the most widely used herbicide which is used in agricultural fields, especially rice fields. The present study investigated the toxicity of Bensulfuron methyl in Cyprinus carpio for the first time.  To this aim, in order to determine the range Finding Test of Bensulfuron methyl, the fishes were randomly divided into 8 groups including 0, 0.01, 0.05, 0.1, 0.5, 1, 2 and 4 g/l Bensulfuron methyl and fish mortality was recorded at 24, 48, 72 and 96 hours. After determination of the range Finding Test, the fishes were randomly divided into 5 groups in three replicates at concentrations of 0, 1.2, 1.4, 1.6 and 1.8 g/l of Bensulfuron methyl and the fish mortality were recorded at 24, 48, 72 and 96 hours. Then, the data were analyzed using Probit analysis by SPSS software and LC1-99 including LC1, LC10، LC30، LC50، LC70، LC90 were calculated. The results showed that fish mortality increased with increasing concentration of Bensulfuron methyl and exposure duration, and the lethal concentration of Bensulfuron methyl decreased with increasing exposure duration. So that, the LC50 at 24, 48, 72 and 96 hours were 1.86, 1.82, 1.75 and 1.62 g /l, respectively. In this study Maximum Allowable Toxicant Concentration (MAC), No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) of Bensulfuron methyl were calculated 0.162, 0.162 and 1.41 g/l, respectively.