Evaluation of Environmental Estrogens in Japanese Rivers

In recent years, a new water environment problem has emerged, so called endocrine disruptors (EDs) that may have adverse effects particularly on the reproductive functions of human beings and organisms. Because almost no studies of EDs in water environments had been conducted before, the Ministry of Construction (MOC) decided to survey the actual pollution conditions of EDs in major rivers and sewage in sewerage systems in 1998. In this paper, we focus on EDs in river waters. First, the summary results of the two-year nation-wide river survey on the chemical basis were briefly described. Because the scope of EDs still focuses on a limited number of chemicals and their quantitative relationship between dose and response is unknown in most EDs, a more comprehensive evaluation is necessary to clarify the present EDs pollution. Based on the estrogenic potential of the surveyed chemicals evaluated with an in vitro assay using recombinant yeast, the results of the nation-wide river survey were evaluated. At the same time, the estrogenic effects of the river water itself that was simultaneously collected in the nation-wide survey were investigated with the same assay. Finally, the most concerned chemicals among the EDs studied in the nation-wide survey and the differences in the evaluation between on the chemical and on the in vitro assay basis were discussed.