Crop soils pollution by heavy metals, the Alacran mining area, Córdoba-Colombia

Contaminación de suelos agrícolas por metales pesados, zona minera El Alacrán, Colombia

In El Alacrán mining zone, Puerto Libertador town (Córdoba, Colombia), is evident the natural resources degradation as a result of informal gold mining; however,in this area, the knowledge about problems related to crop soil pollution by heavy metals exploitation is deficient, considering the serious environmental impacts that it has been causing. The aim of this research was to evaluate mercury, iron and copper pollution in crop soils, and its relationship with some soil chemical characteristics through multivariate analysis. The study area was 1.4 ha, which were located five kilometers downstream of the Alacrán mine dump in the Valdéz stream. 25 soil samples were collected between uncultivated and cultivated areas, with a density of 17.8 sample / ha. The results showed excessive total concentrations for iron and copper, and low for mercury, indicating copper contamination in agricultural soils with TCu values that exceeded the maximum permissible in all international standards; In contrast, mercury values did not indicate pollution. The chemical properties of pH, MO and CICe control the concentrations of Cu and Fe metals in the soil, both for total and available forms. No statistical evidence was found to identify different soil populations in relation to the chemical properties and heavy metals evaluated.