Determination the Lethal Concentration (Lc50 96H) of Diazinon and Machety (Butachlor) on (Vimba vimba persa)

The acute toxicity of Diazinon insecticide and Machete (Butachlor) herbicide were studied according to standard methods of O.E.C.D (1989) and statistic condition during 4 days (96 hours). During the Experiment period, different water factors such as: pH, water hardness, temperature and dissolved oxygen were determined, with 7 to 8.2, 240 mg.L-1, 25 ± 1ºc, and 7ppm respectively. In this investigation, the sample size was 180 pieces of Vimba vimba persa fish (1 to 2gr) and blank. The fish under 5 treatments with 3 replications were used as the control. Each of 10 fish were transferred to each of 20-liter aquariums. First, preliminary experiments were tested several times in order to determine the case fatality. The results figured out that the rate of acute toxicity (Lc50 96h) for Diazinon and machety (Butachlor) on 1 to 2 grams vimba vimba persa fish were, 0.09 and 0.61 mg.L-1, respectively. Finally, the Lc10, Lc50 and Lc90 were measured using the Probit Analysis Statistical method, as 0.069, 0.091 and 0.120 mg.L-1 for the Diazinon insecticide and 0.58, 0.61 and 0.66 mg. L-1 for machety (Butachlor) herbicides. According to the standard, levels of toxic pesticide and herbicide are classified in the range of "very toxic" foe vimba vimba persa fish (1-2gr).