Magnetic parameters as indicators of major elements and lead contamination in urban soils from Aburrá valley, Colombia

  • Alexander Sánchez-Duque Tecnológico Nacional de México, campus Valle de Morelia, km 6.5 Carretera Morelia -Salamanca, C.P. 58100 Morelia, Mich., Mexico.
  • Francisco Bautista Laboratorio Universitario de Geofísica Ambiental (LUGA), Centro de Investigaciones en Geografía Ambiental (CIGA), Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, C.P. 58190, Morelia, Mich., Mexico.
  • Rubén Cejudo Laboratorio Universitario de Geofísica Ambiental (LUGA), Instituto de Geofísica Unidad Michoacán (IGUM), Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, C.P. 58190, Morelia, Mich., Mexico.
  • Avto Goguitchaichvili Laboratorio Universitario de Geofísica Ambiental (LUGA), Instituto de Geofísica Unidad Michoacán (IGUM), Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, C.P. 58190, Morelia, Mich., Mexico.
  • Miguel Cervantes-Solano Escuela Nacional de Estudios Superiores Unidad Morelia, Antigua Carretera a Pátzcuaro 8701, C.P. 58190, Morelia, Michoacán, Mexico.
Keywords: Magnetic parameters, soil, contamination, lead, major elements, threshold value, spatial distribution, Aburrá valley, Colombia

Abstract

We report an environmental magnetism study aimed to determine the relationship between heavy metals and magnetic parameters in urban soils of the Metropolitan Area of Aburrá Valey, Colombia, in order to establish magnetic indicators which in turn may allow the identification of high pollution areas. The study was carried out on 83 urban soil samples, which were subjected to a magnetic analysis, the concentration of the major elements (Al2O3, Fe2O3 and MnO) and Pb concentration determined by means of X-ray fluorescence. A significant variation is observed in the distribution of the magnetic material in the urban soil, which contains a mixture of relatively low coercivity magnetite minerals of both natural and anthropogenic origin. Superparamagnetic size particles were detected in medium and low concentrations in soils with low anthropic activity, suggesting a natural origin. On the other hand, by combining the magnetic parameters and thermomagnetic curves, soils with a high concentration of anthropic magnetic mineral were revealed. Al2O3 and Fe2O3 concentrations are high in most urban soils compared to MnO content. The areas characterized with low anthropic activity showed low content of Pb.

The soils with low anthropic activity was used to determine the reference value for each element and magnetic parameter. Statistical analysis showed that soils have a directly proportional relationship between the magnetic material and the Pb content and inversely proportional to the Al2O3, Fe2O3 and MnO contents. It was demonstrated that the mathematical model that predicts the concentration of elements from magnetic parameters has an efficiency of 62 %. The area characterized with high values of magnetic parameters and Pb content represents 25 % (46 km2) of the total studied urban area.

Published
2020-11-24
Section
Articles