Metallic trace elements contained in the sediments of Dayet Er-Roumi Lake (Morocco) Sara El Ghizi, Sliman Hssaissoune, Mohammed El Bouch, Mohamed Sadik and Mustapha Hasnaoui E3S Web Conf., 298 (2021) 05004 Published online: 05 August 2021 DOI: 10.1051/e3sconf/202129805004