43 A. Limam et al. Research ES S27 Environmental Sciences, Vol. 14, Supplement (2007) 043–052 Assessment of Estrogenic Activity in Tunisian Water and Wastewater by E-Screen Assay Atef Limam † , Terence P.N. Talorete 1,† , Mourad Ben Sik Ali, Mitsuko Kawano 1 , Amel Ben Rejeb Jenhani 2 , Yukuo Abe 1 , Ahmed Ghrabi and Hiroko Isoda 1,* Centre of Research and Technologies of Water, BP. 273, 8020 Soliman, Tunisia 1 Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki 305-8572, Japan 2 Laboratoire Aquaculture et Milieu, Institut National Agronomique de Tunisie, 43, Avenue Charles Nicolle, 1082 Tunis-Mahrajène, Tunisia (Received June 28, 2007, accepted October 23, 2007) * E-mail: isoda@sakura.cc.tsukuba.ac.jp Key words: estrogenic activity, Tunisia, wastewater, surface water, E-screen, enzyme-linked immunosorbent assay Wastewater and surface water samples from three wastewater treatment plants (WWTPs) and three rivers in Tunisia were assayed for estrogenic activity using the E-screen assay and enzyme-linked immunosorbent assay (ELISA). Results showed that all the Tunisian raw wastewater samples as well as the Roriche river water sample induced a strong proliferative response in human MCF-7 breast cancer cells. Tunisian responses in aquatic organisms. Results further showed that the Mornag WWTP, which than the stabilization ponds of the Gammart and pilot WWTPs. This study, which is underscores the need to detect and monitor the estrogenic activity of water and waste- water, given the scarcity of water in Tunisia and the detrimental impact of endocrine- disrupting compounds on the physiology of both animals and humans. 1. Introduction The detection of estrogenic compounds in water and wastewater has become in- creasingly important to the water industry and regulatory authorities, particularly in semiarid countries such as Tunisia, where water is scarce. To date, no such study has been conducted in Tunisia and information on the presence of these compounds in Tu- nisian water and wastewater is nil. stretches of UK rivers. (1) Endocrine-disrupting compounds (EDCs) are known to inter- fere with endocrine function (2) and have been linked to changes in sex ratio, embryonic damage, and reduced fecundity in various vertebrate species. (3–7) Aquatic organisms are particularly vulnerable to the effects of EDCs as aquatic sys- - † Both authors contributed equally to this study.