Effect of magnetite nanoparticles on heavy metals behavior in contaminated soils

The extraction and processing of minerals produce significant environmental impacts that last long after mining operations have ended. Abandoned mines provide obvious sources of contamination by metals and arsenic in surrounding areas. These areas typically support sparse vegetation, so weather events, typical of Mediterranean environments such as heavy rains, can drag metals and metalloids, in a more or less available form for vegetation, as in solution and suspension to accumulate in lower lands. In this study, the area affected by a copper mine, abandoned early last century in the Sierra de Madrid, was sampled. Soil properties such as pH, EC, total OM and texture were analyzed. Furthermore, the BCR (Bureau Community of Reference) fractionation of metals was carried out in order to evaluate the weathering of the starting materials and the selective movement of different fractions along the slope . Metals and arsenic were detected beyond the mine limits, in areas where water flows in a preferential way. Results showed high concentrations and readily extractable Cu and As, which may suggest potential bioavailability for organisms and may create an environmental risk and potential human exposure what results in a health risk for the population.