Cd2+ and Zn2+ sorption on apatite in the presence of EDTA and humic substance K. Viipsi, S. Sjöberg, K. Tõnsuaadu and A. Shchukarev E3S Web of Conferences, 1 (2013) 01008 Published online: 23 April 2013 DOI: 10.1051/e3sconf/20130101008