Field availability and mobility of metals in Ferralsols developed on ultramafic rock of Niquelândia, Brazil

Ultramafic (UM) rocks are defined as igneous that contain more than 90% of mafic minerals. Soils derived from ultramafic rock generally nutrient-deficient and have concomitant high concentrations potentially phytotoxic trace elements (Ni, Cr, Co, Mn). Consequently, to assess the dynamics nutrients metals in complex Niquelândia (Brazil), soil solutions been sampled soils characterized by Cr(VI) availability. The metal contents surficial water also analyzed investigate metals’ leaching mobility. Soil featured low nutrient contents, a large Ca:Mg imbalance, Ni Cr concentrations. Chromium was present its toxic dissolved form (Cr(VI)) solutions. Metals were often above limit for biota therefore able affect functioning. behavior topsoil appeared be primarily controlled organic matter, while likely released Fe-oxides anionic exchange. This result agreed with lability assessed using isotopic exchange kinetics companion study. In these serpentinic tropical soils, highly leached Fe-oxide horizons appear play role sequestration diffuse labile Ni, respectively, deeper part profiles topsoil. At catchment scale, results suggest may exported surrounding ecosystems not adapted metals.