Assessment of the Acute Toxicity of Oil Dispersant Type 3 (4− amino−1, 2− dithiolane−4− carboxalic acid) on Abudefduf vaigiensis Under Laboratory Conditions

This study was designed to determine the acute toxicity of type 3 oil dispersant (4− amino−1,2−dithiolane−4−carboxalic acid) on shallow coastal marine fish, Abudefduf vaigiensis under laboratory conditions. Two separated experimental tank series were used providing aeration to one series and other without aeration. Four replicates of each concentration value of the oil dispersant were used including one control tank for each concentration series. Eight fish of same size range of (4.2cm to 5.4cm) were put into each tank and several prior exposed tests were carried out to determine the chemical concentration range of acute toxicity on the selected fish. There was no significant difference of temperature, pH, NH3 and salinity in both setups. Dissolve oxygen (DO) concentration decreased during 10 hours of the experiment and after that DO was constant in the aerated tank series. Several behavioral changes (slime secretion, color change, increase of operculum movement rate and surface breathing) were observed in both setups. Zig-zag swimming behavior of fish was observed in the un aerated setup. Mortality of the first fish was observed after 6 hours in the aerated tanks. Since, DO is one of the factors for fish mortality, after 9 hours of the experiment fish mortality was observed in the aerated tanks. According to the results from Probit analysis program, Version 1.5, LC50 values varied from 31.37-33.715 ppm in aerated tanks and these values changed between 70.702 and 71.825 ppm in not aerated tanks. Therefore, the range (70.702-71.825 ppm) of the type 3 oil dispersant could be considered as the acute toxicity level for Abudefduf vaigiensis for the natural environmental conditions.