Contamination of water and food crops by trace elements in the African Copperbelt: A collaborative cross-border study in Zambia and the Democratic Republic of Congo oleh Ambayeba Muimba-Kankolongo, Célestin Banza Lubaba Nkulu, Jacob Mwitwa, Florence M. Kampemba, Misery Mulele Nabuyanda, Vincent Haufroid, Erik Smolders, Benoit Nemery