Horizontal and Vertical Distribution of Estrogenic Activities in Sediments and Waters from Tokyo Bay, Japan
Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter above the limit of detection) in river water samples ranged from 0.70 to 4.01 ng/L, in seawater samples from 0.34 to 2.52 ng/L, and in surface sediments from 2.07 to 12.1 ng/g. The relationship between salinity and estrogenic activity in water samples suggested that fresh water is one source of environmental estrogens in Tokyo Bay. Fractionation of sediment extracts showed that the highest estrogenic activity was observed in the midpolar fraction. The observed activities were compared with activities mediated by known concentrations of nonylphenol, bisphenol-A, estrone, and 17-estradiol. In sediment collected near the sewage treatment plants, the estrogenic activity of the midpolar fraction could be explained about 34% by nonylphenol and estrone contained in this fraction. Core sediment measurements detected estrogenic activity from as far back as the 1960s. The regulations on the industrial wastewater in early 1970s would be one of the main reasons for the lower estrogenic activity in the upper section of the sediment core. The high estrogenic activities as measured in water and sediment samples from Tokyo might be restricted to certain coastal areas.