Fate of emerging substances from a former landfill ; Devenir de substances émergentes depuis une ancienne décharge ; Fate of emerging substances from a former landfill: Transfer of emerging substances by groundwater from a former municipal landfill (Nantes, France) ; Devenir de substances émergentes depuis une ancienne décharge: Transfert de substances émergentes par les eaux souterraines depuis une ancienne décharge municipale (Nantes, France)

International audience ; Sites contaminated by point source pollution such as landfills frequently impact the quality of groundwater. Due to the diversity of waste deposited, landfills are sources of a wide variety of contaminants, including emerging substances. The former municipal landfill of Prairie de Mauves, located in Nantes (France) on alluvium of the Loire estuary, illustrates this. This pilot site is part of the SAFIR network and of the national observation system on cities (SNO Observil). Daily recording of piezometric levels, groundwater electrical conductivity and temperature at different points has been in place since 2014. 9 emerging substances were searched for among more than 80 quality parameters between 2013 and 2019 in leachate as well as in the groundwater upstream and hydraulically downstream of the site. Six (6) emerging substances were quantified in the leachates, including endocrine disruptors (such as Bisphenol A up to 23 µg/l and tolyltriazole up to 0.87 µg/l). Most of the substances detected in the leachate were found in groundwater immediately downstream of the site, much less a few hundred meters further. Bisphenol A is found far downstream.Former landfills are likely to generate diffuse pollution of continental (ground and surface), estuarine and marine waters. Impacts on (aquatic) fauna are also possible. A better characterization of the molecules generated by these sites therefore appears necessary, as does a better understanding of their fate. ; Les sites contaminés par des pollutions ponctuelles comme les décharges impactent fréquemment la qualité des eaux souterraines. Du fait de la diversité des déchets déposés, les décharges sont sources d'une grande variété de contaminants, incluant des substances émergentes. L'ancienne décharge municipale de la Prairie de Mauves, située à Nantes (France) sur des alluvions de l'estuaire de la Loire, permet de l'illustrer. Ce site atelier fait partie du réseau SAFIR et du SNO Observil. Un enregistrement quotidien des niveaux piézométriques, ...