Joint toxicity of Cu2+ and Cd2+ to early development of zebrafish embryos.

The toxicities of two heavy metals Cu2 + and Cd2 + to embryo development were determined using the zebrafish embryo early development toxicity technique.The dose-response curves of the two heavy metals could be effectively characterized by the Logit and Weibull functions on the two toxicity endpoints of 24 h lethal rate and 72 h hatch inhibition rate.The median lethal concentration(LC50) and the median effect concentration(EC50) calculated by the best-fitted functions were used as the toxicity evaluation criteria.The toxicity order of the two heavy metals on the two observed toxicity endpoints according to the value of either LC50 or EC50 both showed that Cu2 + Cd2 +.The joint toxicity was predicted using the mixture ratio of the non-observed effect concentration(NOEC) of 72 h hatch inhibition rate by two models of concentration addition(CA) and independent action(IA),then compared with the 95% confidence intervals of the mixture experimental data.The results indicated that the two models could both predict joint toxicity of zebrafish embryo hatching effectively.