The estrogenic activity in water at various localities on Lake Biwa-Yodo River, a representative watershed in Japan, was measured using a recombinant yeast that expresses the human estrogen receptor. The yeast bioassay revealed that the activities of 13 water samples had an average value of 14 pmol/L (3.8 ng/L) (17beta-estradiol equivalent) with a very wide range from 0 to 72 pmol/L (0-19.6 ng/ L), and two of the samples had prominent levels of activity (72 pmol/L (19.6 ng/L) and 56 pmol/L (15.2 ng/L)). We analyzed these two samples with instrumental approaches. A high-performance liquid chromatogram profile showed that the strong activity in one sample, which was collected just downstream of a sewage-treatment plant, would be due to 17beta-estradiol and estrone, whose source is considered to be human urine contained in the effluent of the plant. The activity in the other sample, which was obtained from a tributary river in a primarily residential area with some industrial development (i.e., Osaka City), however, did not correspond to 17beta-estradiol, estrone, or synthetic chemicals known as estrogenic. Analysis of a fraction with estrogenic activity by liquid chromatography-mass spectrometry (LC-MS) provided evidence that the activity in the water sample resulted from the presence of genistein, an isoflavone compound of plant origin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.