Horizontal and Vertical Distribution of Estrogenic Activities in Sediments and Waters from Tokyo Bay, Japan S. Hashimoto, 1 A. Horiuchi, 2 T. Yoshimoto, 3 M. Nakao, 3 H. Omura, 3 Y. Kato, 4 H. Tanaka, 5 K. Kannan, 6 J. P. Giesy 6 1 Institute for Environmental Sciences, University of Shizuoka, Shizuoka 422-8526, Japan 2 Department of Ocean Sciences, Tokyo University of Fisheries, Tokyo, 108-8477, Japan 3 Yakult Central Institute for Microbiological Research, Tokyo, 186-8650, Japan 4 School of Marine Science and Technology, Tokai University, 424-8610, Japan 5 Independent Administrative Institutions Public Works Research Institute, Ibaraki 305-8516, Japan 6 National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan 48824, USA Received: 10 September 2003/Accepted: 23 June 2004 Abstract. Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan.Weaimedtodetermineestrogenicactivityinextractsof 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. E 2 equivalents (ng E 2 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 salinityandestrogenicactivityinwatersamplessuggestedthat fresh water is one source of environmental estrogens in Tokyo Bay. Fractionation of sediment extracts showed that the high- est estrogenic activity was observed in the midpolar fraction. The observed activities were compared with activities medi- ated by known concentrations of nonylphenol, bisphenol-A, estrone, and 17b-estradiol. In sediment collected near the sewage treatment plants, the estrogenic activity of the mid- polar fraction could be explained about 34% by nonylphenol and estrone contained in this fraction. Core sediment mea- surements 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 estro- genic 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. There has been considerable concern about endocrine-dis- rupting chemicals (EDCs) detected in the environment and their potential to cause deleterious physiological effects in humans and wildlife (Jobling and Sumpter 1993). Endocrine disruption has a multitude of mechanisms and actions, including effects on growth, behavior, reproduction, and im- mune function. EDCs are found in the aquatic environment, especially in discharges from sewage treatment plants. For example,alkylphenolssuchasnonylphenolareknowntoexert estrogenic activity in aquatic organisms (Gray and Metcalfe 1997; Staples et al. 1998), and are present in effluents from sewagetreatmentplantsandalsoinriverwater,sediments,and fish tissue (Yamagishi et al. 1997; Lye et al. 1999). The appearance of intersex fish in the aquatic environment, especially in wastewater effluents, has led to the hypothesis that substances in sewage effluent might be estrogenic to fish. Estrogens induce vitellogenin, a precursor protein for egg yolk that has been used as a sensitive biomarker for studies of xe- noestrogens in aquatic environments (Harries et al. 1997; Al- len et al. 1999a, 1999b; Minier et al. 2000; Simpson et al. 2000;OberdçrsterandCheek2001;vanAerle et al. 2001).We previously found vitellogenin induction and intersex gonads, two bioindicators of the effects of environmental estrogens, in maleflounder, Pleuronectes yokohamae,collectedfromTokyo Bay, Japan (Hashimoto et al. 1998b, 2000). Intersex charac- teristics, such as the presence of perinucleolar oocytes, have also been found in male konoshiro gizzard shad (Konosirus punctatus) collected from inner Tokyo Bay (Cho et al. 2003). Contamination of the waters of Tokyo Bay by environmental estrogens may cause vitellogenin induction and the develop- ment of intersex gonads in local male fish. Severalassayshavebeendevelopedtoassessenvironmental samplesforestrogenicactivitymediatedbyestrogenreceptors. Inrecentyears,estrogenicactivityinwastewater(Kçrner et al. 2001; Kirk et al. 2002), river water (Fenet et al. 2003), sea- water (Koh et al. 2002), and sediment (Kannan et al. 2000; Koh et al. 2002; Fenet et al. 2003) has been analyzed by in vitro bioassays. They demonstrate the total estrogenic activity of environmental samples, regardless of which compounds are responsible for the activity. The results of these studies indi- cate that estrogenic activity varies widely among sampling sites (Koh et al. 2002). Correspondence to: S. Hashimoto; email: hashimos@u-shizuoka- ken.ac.jp Arch. Environ. Contam. Toxicol. 48, 209–216 (2005) DOI: 10.1007/s00244-003-0205-3