Acute toxicity bioassay of the mercury chloride and copper Sulphate in Rutilus caspicus and Rutilus kutum

The purpose of this present study is to determine the acute toxicity (LC^sub 50^) of HgCl2 and CuSO^sub 4^ in Caspian roach (Rutilus caspicus) and CuSO^sub 4^ in Caspian kutum (Rutilus kutum). The Caspian roach LC^sub 50^ values for HgCl2 at 24, 48, 72, and 96-hrs of exposure, were 0.64, 0.61, 0.42, and 0.28 mg L^sup -1^, respectively, and for CuSO4 were 11.55, 5.08, 2.49, and 1.47 mg L^sup -1^, respectively. The Caspian roach LC^sub 50^ values for CuSO4 at 24, 48, 72, and 96-hrs of exposure, were 5.31, 4.17, 3.20, and 2.25 mg L^sup -1^, respectively. The results of this study showed that the toxicity of HgCl2 is higher than that of CuSO^sub 4^ for the studied species. The mortality decreased with time, and most of the deaths were occurred during the first 24 hrs.