acute toxicity of mercuric chloride (hgcl2), lead chloride (pbcl2) and zinc sulfate (znso4) on silver dollar fish (metynnis fasciatus)

background: since heavy metals can accumulate in the tissues of aquatic organisms, they can cause a range of hazardous effects which can become harmful to humans. the aim of this study was to investigate the acute effects of some heavy metals as potential dangerous substances by assessing the mortality effects of mercuric chloride (hgcl2), lead chloride (pbcl2) and zinc sulfate (znso4) pollutants on a freshwater fish, silver dollar (metynnis fasciatus). methods: fish samples were exposed to different concentrations of mercuric chloride (hgcl2), lead chloride (pbcl2) and zinc sulfate (znso4) for 96h and their cumulative mortality was calculated in 24h intervals.results were analyzed by spss 16 to obtain number of cumulative mortality and lethal concentrations (lc10-99). results: lc50-96h was 0.94±0.41ppm, 86.84±1.04ppm and 32.24±1.41ppm for mercuric chloride, lead chloride and zinc sulfate, respectively. so, mercury had the highest toxicity to silver dollar fish. conclusion: mercuric chloride and lead chloride has the lowest and highest rate of mortality among these tree metals on silver dollar fish however, the mortality rate was increased with increasing concentrations of toxins with time.