determination of lethal concentration of mercuric chloride (hgcl2), chloride lead (pbcl2) and zinc chloride (zncl2) in silver carp (hypophthalmichthys molitrix)

abstract heavy metals are the important pollution which there is in the aquatic ecosystems. today, with advances in technology have increased the pollution therefore it is important to assessment the risks. the aim of this study was acute toxicity effects of mercury chloride, lead chloride and zinc chloride in silver carp fish. in this study there were 5 treatments for lead chloride and mercury chloride and 6 treatments for zinc chloride. the average lethal concentration (lc50) of these insecticides on fish within 96 hours was determined using probit analysis. toxicity tests at 96 hours, 100% mortality shown at 1 mg per liter concentration for mercuric chloride and 60 mg per liter concentration for lead chloride and zinc chloride. lc50 96h was for mercuric chloride 0.55±0.63, lead chloride 39.9±0.76 and zinc chloride on 41.1±0.20. based on this it was concluded that mercury chloride more toxic to silver carp fish compare to lead and zinc chloride so we should prevent the entrance of such substances, specific mercury, to the aquatic ecosystems.