Comparison between estrogenicities estimated from DNA recombinant yeast assay and from chemical analyses of endocrine disruptors during sewage treatment

This study discusses the estrogenicity and the extent of estrogenic effects, of sewage and treated sewage in public sewage treatment plants in Japan. The estrogenicity in this study was measured with a DNA recombinant yeast strain. Using this method, 43 chemicals that are suspected to have estrogen-like effects were measured and their estrogenicities were evaluated in terms of 17β-estradiol equivalents by comparison with the estrogenicity of 17β-estradiol. 17β-estradiol equivalents of influent and effluent sampled from 20 sewage treatment plants (STPs) were measured with this method. Because the concentrations of endocrine disruptors (EDs) in the STPs were monitored by the Ministry of Construction (MOC), the estrogenic effects estimated from the chemical data were obtained as a theoretical estrogenicity in terms of 17β-estradiol equivalent. The results suggest that STPs effectively reduce the estrogenicity and the theoretical estrogenicity during treatment, and that there were some differences between the estrogenicity assayed by the yeast and the theoretical estrogenicity in many STPs, particularly in influent sewage. Therefore, it is implied that unknown estrogen-like substances or antagonists might exist in influent sewage and treated sewage in STPs.