determination lethal concentration (lc50 96h) mercuric chloride (hgcl2), lead chloride (pbcl2) and zinc chloride (zncl2) on survival goldfish (carassius auratus)

chemical pollutants presence in water may induce severe ecological consequences and consequently affecting aquatic ecosystems integrity. heavy metals are dangerous pollutants for aquatic inhabitants that have a great stability. heavy metals contamination (pollution) of the surface waters happens widely by discharge of mill effluents. the objective of the present study was to determine the 50% lethal concentration (lc50), mercuric chloride (hgcl2), lead chloride (pbcl2) and zinc chloride (zncl2) on survival goldfish (the average weight 10±0.25 gr and mean length 6 cm). fish were exposed for 96 hours in 5 treatments lead chloride and mercuric chloride and zinc chloride for 8 treatments, each treatment was performed in three repetition. these experiments carried out in static condition and based on trc, 1984 standard method, and controlled of the effective water physico–chemical factors that having ranges ph, do and temp. on the base of obtained results by probit program lc50 value of lead chloride, mercuric chloride and zinc chloride in 96 hours were 88.8±0.05, 0.87±0.41 and 92.6±0.05 mg/l on carassius auratus, respectively. based on 50% lethal concentration the toxicity of materials was determined include mercury chloride, lead chloride and zinc chloride, respectively in goldfish and also mac (maximum allowable concentration) value of mercury chloride, lead chloride and zinc chloride were determined 0.087, 8.88 and 9.26 mg/l for goldfish, respectively.