Assessing the toxicity of bisphenol A and its six alternatives on zebrafish embryo/larvae

Bisphenol A (BPA) analogues are gradually replacing BPA in the plastics industry. Whether these alternatives are indeed safer than BPA itself, however, remains unclear. Here, we studied the toxicity of BPA and six of its alternatives-BPB, BPC, BPE, BPF, BPAF, and BPAP-using zebrafish embryos/larvae. According to their half lethal concentration (LC₅₀) values, the acute toxicity of BPA and six alternative bisphenols to zebrafish embryos, from highest to lowest, was BPAP ≈ BPAF > BPC > BPB > BPA > BPE > BPF. Under nonlethal concentrations, the tested bisphenols had different toxic effects on development in terms of reducing the hatching rate, frequency of spontaneous movements, and heart rate in the embryo, as well as inducing yolk sac edema, pericardial edema, and spinal deformation in the larvae. The estrogenic activity of BPE, BPF, and BPAF was higher than that of BPA, as shown by vtg1 expression assays. Moreover, BPA and its alternatives increased SOD activity and cell apoptosis in embryos/larvae under nonlethal concentrations. Our findings indicate that BPA alternatives may not be safer than BPA in zebrafish, and that these BPA alternatives should be applied with caution.