acute toxicity bioassay of the mercury chloride and copper sulphate in rutilus caspicus and rutilus kutum

the purpose of the present study was to determine the acute toxicity (lc 50 ) of hgcl 2 and cuso 4 in caspian roach ( rutilus caspicus ) and cuso 4 in caspian kutum ( rutilus kutum ). the caspian roach lc 50 values for hgcl 2 at 24, 48, 72, and 96-hrs of exposure, were 0.64, 0.61, 0.42, and 0.28 mg l -1 , respectively, and for cuso 4 were 11.55, 5.08, 2.49, and 1.47 mg l -1 , respectively. the caspian roach lc 50 values for cuso 4 at 24, 48, 72, and 96-hrs of exposure, were 5.31, 4.17, 3.20, and 2.25 mg l -1 , respectively. the results of this study showed that the toxicity of hgcl 2 is higher than that of cuso 4 for the studied species. the mortality decreased with time, and most of the deaths were occurred during the first 24 hrs.