Fish test for endocrine-disruption and estimation of water quality of Japanese rivers

The LC50 values (72 h) of 17β-estradiol (E2), p-nonylphenol (NP) and bis-phenol-A (BPA) to adult male and female medaka were 3.5 and 3.5, 0.85 and 0.87, and 6.8 and 8.3 mg L−1, respectively; the LC50 values to embryos were 0.46, 0.13 and 5.1 mg L−1, respectively. The IC50 values for inhibition to egg hatching were 0.47, 0.85 and 9.0 mg L−1, respectively. These values were much higher than concentrations detected in river water in Japan and the chemicals were considered to have no lethal effect on the fish in an aquatic environment. Mature male medaka was continuously exposed to 0.005, 0.05 or 1.0 μg L−1 of E2, or to 0.1, 10 or 100 μg L−1 of NP or BPA. Female specific proteins (FSP) were induced in the blood of male medaka that were exposed for 5 weeks to E2 higher than 0.005 μg L−1, NP higher than 0.1 μg L−1, or BPA higher than 10 μg L−1. Based on these FSP inducible concentrations and reported concentrations of E2, NP and BPA in Japanese river water, some river water contaminated by E2 or NP could be estimated as the FSP inducible in male medaka.