Effect of the organic matter quality associated with the use and management of soils in the cadmium retention in high Andean systems of Colombia

摘要

Cadmium from soils by weathering and anthropogenic activities can have produce toxic effects associate to low affinity of adsorbents forms, high solubility and mobility. It is very important to conduct studies leading to knowledge of adsorption phenomena and cadmium mobility factors and predict possible toxicity in High Andeansoils whose use is changing to pastures and crops with applications of phosphate fertilizer with presence of Cd in composition. High Andean soils subbasin Rio Las Piedras, (Department of Cauca), with systems of forest, crop and pasture were characterized by physical and chemical properties, highlighting strong acidity, presence of allophones, high in organic carbon, high cation exchange capacity, low density of soil. The quality of soil organic matter was assessed by different humification index obtained with the different fractions characterized to determine the influence on cadmium retention phenomenon and mobility factor. The retention was evaluated by Freundlich adsorption isotherms in humic acids and soils of the three systems. The K (maximum adsorption capacity) and n (retention force) values correspond to 131. 98 and 1.18 in forest soils, 340.93 and 1.19 for crop, 170.36 and 1.19 in pasture, and are lower than those of humic acids in the three systems. The quality of the organic matter has a significantly effect on these processes, better quality results in less mobility preventing groundwater contamination and bioaccumulation toxicity.