Agricultural Research Council, Research Center for the Soil-Plant System, Roma, Italy;
Department of Agro-Environmental Science and Technology, University of Bologna, Bologna, Italy;
ILSA SpA, Arzignano, Italy;
Organic; Fertilizers; Tanned; Hides; and; Skins; Hydrolyzed; Leather; Trivalent; Chromium; Hexavalent; Chromium; Soil;