Toxic Effects of 4-Nonyl Phenol on Zebrafish (Danio rerio) Embryo/Larva

4-Nonylphenol (4-NP), a stable environmental endocrine disruptor, exerts negative effects on the growth and development of organisms. Danio rerio embryos were exposed to a series of concentrations of 4-NP at 2.0, 5.0, 10.0, 25.0, 50.0 and 125.0 μg·L^-1 for 120 h. During the exposure, the mortality, hatching rates and abnormalities of embryos, as well as the body length and heart rates in 30 s were recorded everyday till the larva in the control group began to die as a result of hunger. The results show that the LC₅₀ of Danio rerio embryos exposed to 4-NP after 48, 72 and 96 h were 131.4, 47.2 and 26.8 μg·L^-1, respectively. The hatching rate of Danio rerio embryos significantly declined due to the lethal effect of 125.0 μg·L^-1 of 4-NP. In addition, exposure to 4-NP significantly increased the tail malformation and pericardial cyst rates of Danio rerio embryos. A positive dose-response relationship was observed in the tail malformation rates. Compared to the control group, the Danio rerio larva in all 4-NP treatment groups had shorter body length and less 30 s heart rates. These results suggested that exposure to 2.0 μg·L^-1 concentration of 4-NP can exert teratogenic and lethal effects on the Danio rerio embryos.