Toxicity of Dye Effluent on Japanese Medaka (Oryzias latipes) Embryo and Larava
染织排水对日本青鳉幼鱼和胚胎的毒性效应

The effect of toxicity of dye effluent was evaluated by Japanese medaka (Oryzias latipes) from embryo to fry. 4 samples were obtained from the discharge of dye factories. The results of 96 h acute toxicity test showed that sample 3 and 4 had acute toxicity to juvenile fish whereas acute toxicity of sample 1 and 2 was not significant. The acute toxicity units of 4 samples were 0.47, 0.53, 9.93 and 1.68 TUa, respectively. Sample 1 and 2 are mildly toxic, sample 3 was medium toxic and sample 4 was low toxic. For 14 d chronic toxicity, the results showed that the lethal of embryos in sample 1, 3 and 4 were observed, the no observed effect concentrations (NOEC) for hatching rate were 90%, 20% and 33%, respectively. The hatching time are delayed in group of 52% and 64% of sample 4 and significantly different with the control (p>0.05). The inhibition of hatching of embryo were significant, NOEC for hatching rate was 2.5%, and EC25 was 39.2%. The chronic toxicity units of the four samples were 1.11, 40, 5 and 3.03 TUc, respectively. The fish fry were resulted in death by the treatment groups of sample 1 and 3 after 3 d exposure. NOEC for survival rate of fish fry are 90%, 20%, 10% and 64%, respectively.