Estrogenic activities of river water from four representative cross-sections of the Yellow River (Zhengzhou section) and their effects on reproduction and development of fish were assessed. MVLN assay showed estradiol equivalents of river water from Yiluohe, Xinmanghe, Qinhe and Huayuankou cross-sections were 1.09 ± 0.11, 0.72 ± 0.01, 1.19 ± 0.19 and 0.80 ± 0.04 ng/L, respectively. Significant vitellogenin (VTG) inductions were observed in adult male Japanese madaka (Oryzias latipes) after 30 days of exposure to river water from Yiluohe and Qinhe cross-sections (p < 0.05). Hepatic-somatic index was significantly elevated in fish exposed to water from Qinhe cross-section (p < 0.05). A significant delay in time to hatching was observed in embryos treated by water from Xinmanghe cross-section (p < 0.05). Significant lower survivals were observed in fish treated by water from Yiluohe and Xinmanghe cross-sections after a full life cycle exposure (p < 0.05). Exposure of water from Yiluohe and Qinhe cross-sections induced significantly elevated VTG levels in the first sexually mature male fish (p < 0.05). Both the in vitro and in vivo bioassay demonstrate endocrine disrupting chemicals exist in the Yellow River (Zhengzhou section) and fish in Yiluohe and Qinhe cross-sections can be at a risk of reproductive and developmental impairment.
Keywords: Development; Endocrine disrupting chemicals; Japanese medaka (Oryzias latipes); MVLN assay; Reproduction; The Yellow River.