Fate of antibiotics, steroid hormones and multiple endocrine activities during biological treatment of swine manure under anaerobic and aerobic/anoxic conditions S. Combalbert 1 , M. J. Capdeville 2 , V. Bellet 3 , R. Rajagopal 4 , J. C. Motte 1 , P. Balaguer 3 , F. Béline 4 , N. Bernet 1 , H. Budzinski 2 , G. Hernandez-Raquet 1,5 1 INRA- UR050 Laboratoire de Biotechnologie de l’Environnement- Avenue des étangs, F-11100 Narbonne, France (E-mail: bernet@supagro.inra.fr). 2 Université Bordeaux I, EPOC-LPTC, F-33405 Talence, France (E-mail : h.budzinski@epoc.u-bordeaux1.fr). 3 INSERM, U 896-IRCM, F-34197 Montpellier, France (E-mail : Patrick.Balaguer@montpellier.unicancer.fr) 4 IRSTEA, UR GERE, F-350444 Rennes, France (E-mail : beline@irstea.fr) 5 Université de Toulouse, INSA, UPS, INRA UMR792, CNRS UMR5504, Laboratoire d’Ingénierie des Systèmes Biologiques et des Procédés, 135, avenue de Rangueil, F-31077, Toulouse, France (E-mail: hernandg@insa- toulouse.fr). Abstract Little information exists on the fate of antibiotics, hormones and their associated endocrine activity during manure treatment processes. Thus, the aim of this study was to assess the fate of such emerging pollutants and multiple endocrine activities during manure treatment coupling anaerobic digestion and aerobic/anoxic conditions under mesophilic conditions. The thermophilic anaerobic digestion was also studied. The endocrine activities tested include estrogenic (ER), dioxin-like (AhR), peroxisome proliferator receptor gamma (PPAR), pregnane X (PXR) and androgenic (AR) activities. Our results showed that antibiotics and steroid hormones were recalcitrant to biodegradation under anaerobic conditions in both mesophilic and thermophilic temperatures. In contrast, antibiotic and hormone removal reached between 76 to 95 % when anaerobic digestion was coupled to aerobic/anoxic treatment. In absence of anaerobic predigestion, hormone removal in aerobic/anoxic conditions was about 40 %; it suggests that the anaerobic predigestion could favour the further elimination of hormones in the anaerobic/anoxic process. The estrogenic activity was mainly removed in the aerobic/anoxic (71%) compartment. The dioxin-like activity appeared to be more recalcitrant to degradation. No others endocrine activities were detected. Keywords Antibiotics; hormones; anaerobic digestion; emerging pollutants, endocrine disruption, manure. INTRODUCTION Swine manure concentrates a wide spectrum of pollutants from pig breeding activities. For example, pigs produce high quantities of natural steroid hormones, which are involved in the communication between cells. Swine breeding is the main consumer of veterinary antibiotics used to treat bacterial infections. After their action in the organism, hormones and antibiotics are excreted via urines and faeces. Thus, these compounds will be concentrated in manure were they have been detected even after long periods of manure storage under anaerobic conditions. So, hormones and antibiotics can be disseminated in natural ecosystems through manure spreading practices. In the ecosystem, hormones have been associated to endocrine disruption phenomena such as feminisation of wild fish populations while antibiotics have been associated to the development of antibiotic resistance in bacteria (Desbrow et al., 1998; Ding et al., 2010). Manure can also be contaminated by other compounds like polycyclic aromatic hydrocarbons (PAH), dioxin and furans mainly through the surrounding air or by compounds like nonylphenol detergents used for cleaning purposes. These pollutants may also induce endocrine activities through the estrogen receptors, but also through other pathways which are potentially linked with the estrogenic response (Tabb and Blumberg, 2006). These potential activities on the endocrine system can also be found in manure and can be disseminated by manure spreading practices.