Soil attributes related to cadmium and copper adsorption in tropical soils - DOI: 10.4025/actasciagron.v27i4.1348

Abstract

Chemical reactions and physical and biological processes control the adsorption of Cd and Cu by soils. Heavy metal retention by soils can decrease their bioavailability in the soil-solution system. Cd and Cu adsorption were evaluated in in-surface and subsurface horizons of eight Brazilian soils: five Oxisols, two Alfisols and one Ultisol. The maximum adsorption estimated by the linearized Langmuir equation was correlated with some soil attributes. In the surface horizon, Cd maximum adsorption was positively correlated with total CEC, specific surface area, and clay, silt, “free” Fe and “total” Al (extracted by sulfuric acid) contents, while, in the subsurface horizon, the correlation was positive with effective CEC, pH, and “amorphous” Fe contents. Maximum Cd adsorption was also negatively correlated with sand contents in surface horizons. On the other hand, in the surface horizons, maximum Cu adsorption was positively correlated with percentage of Al saturation and clay, “total” and “amorphous” Al oxides contents; in subsurface horizons, it was correlated with pH and clay and “amorphous” Al oxides contents