Differential chemical profiling to identify ozonation by-products of estrone-sulfate and first characterization of estrogenicity in generated drinking water Marc Bourgin a , Gae ¨l Gervais a , Emmanuelle Bichon a, *, Jean-Philippe Antignac a,b , Fabrice Monteau a , Gae ¨la Leroy c , Lauriane Barritaud c , Mathilde Chachignon c , Vale ´rie Ingrand c , Pascal Roche d , Bruno Le Bizec a a LUNAM Universite ´, ONIRIS, Laboratoire d’Etude des Re ´sidus et Contaminants dans les Aliments (LABERCA), 707, 44307 Nantes, France b INRA, Nantes, France c Veolia Environnement Recherche et Innovation, Saint Maurice, France d Veolia Environnement Recherche et Innovation, Maisons-Laffitte, France article info Article history: Received 22 October 2012 Received in revised form 18 March 2013 Accepted 22 March 2013 Available online 18 April 2013 Keywords: Chemical food safety Ozonation Water Estrone-3-sulfate By-products High-resolution mass spectrometry abstract For a few years, the concern of water treatment companies is not only focused on the removal of target micropollutants but has been extended to the investigation of potential biologically active by-products generated during the treatment processes. Therefore, some methods dedicated to the detection and structural characterization of such by-products have emerged. However, most of these studies are usually carried out under simplified conditions (e.g. high concentration levels of micropollutants, drastic treatment conditions, use of deionized or ultrapure water) and somewhat unrealistic conditions compared to that implemented in water treatment plants. In the present study, a real field water sample was fortified at the part-per-billion level (50 mgL 1 ) with estrone-3-sulfate (E1-3S) before being ozonated (at 1 mg L 1 ) for 10 min. In a first step, targeted measurements evidenced a degradation of the parent compound (>80%) in 10 min. Secondly, a non-targeted chemical profiling approach derived from metabolomic profiling studies allowed to reveal 11 ozon- ation by-products, among which 4 were found predominant. The estrogenic activity of these water samples spiked with E1-3S before and after treatment was assessed by the ER- CALUX assay and was found to decrease significantly after 10 min of ozonation. Therefore, this innovative methodological strategy demonstrated its suitability and relevancy for revealing unknown compounds generated from water treatment, and permitted to generate new results regarding specifically the impact of ozonation on estrone-3-sulfate. These results confirm that ozonation is effective at removing E1-3S in drinking water and indicate that the by-products generated have significantly lower estrogenic activity. ª 2013 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: þ33 2 40 68 78 80. E-mail address: laberca@oniris-nantes.fr (E. Bichon). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/watres water research 47 (2013) 3791 e3802 0043-1354/$ e see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.watres.2013.03.050