Magnetic particles as pollution indicators at the Aburrá valley (Colombia)

Alexander Sánchez-Duque¹, Francisco Bautista^1,*, Rubén Cejudo¹, Miguel Cervantes-Solano^1,, Avto Goguitchaichvili¹

¹Laboratorio Universitario de Geofísica Ambiental, Centro de Investigaciones en Geografía Ambiental e Instituto de Geofísica, Universidad Nacional Autónoma de México. Ciudad Universitaria, no.3000, CDMX, México.

* Autor para correspondencia: (F. Bautista) This email address is being protected from spambots. You need JavaScript enabled to view it.

How to cite this article:

Sánchez-Duque, A., Bautista, F., Cejudo, R., Cervantes-Solano, M., Goguitchaichvili, A., 2023, Las partículas magnéticas como indicadoras de contaminación en el Valle de Aburrá (Colombia): Boletín de la Sociedad Geológica Mexicana, 75 (1), A181122. http://dx.doi.org/10.18268/BSGM2023v75n1a181122

Manuscrito recibido: 14 de Febrero de 2022; Manuscrito corregido: 30 de Mayo de2022; Manuscrito aceptado: 3 de Noviembre de 2022.

ABSTRACT

This paper reports the results of an environmental magnetism research carried out with the main objective of determining the spatial variation of pollution in the urban area of Metropolitan Area of the Aburrá Valley (Colombia). A two-dimensional sampling was designed in which 99 sampling sites were defined, each site was georeferenced and described by categorical factors of land use, road hierarchy, road surface, soil group or geological unit, plant species collected and city or municipality. A total of 307 environmental samples were collected, of which 110 were of urban surface soil, 99 of urban dust and 98 leaves of public ornamental plants. Rock magnetism techniques were performed to determine the nature of the magnetic minerals present in the samples. A non-parametric analysis of variance was made to relate the magnetic parameter values to the categorical factors and reveal the possible sources of the magnetic particles. After that, using the magnetic magnification factor in the dust and surface soil samples, the area and sample zone specific contamination reference values were defined. From the calculated and geo-referenced values, maps were designed showing descriptive models of the environmental contamination for each urban area according to the nature of environmental sample and magnetic parameters. The results reveal that the magnetic signal in the sites with the highest concentration of magnetic minerals is dominated by ferrimagnetic minerals of anthropogenic origin. Non-parametric analyses of variance show that a higher relative concentration of these minerals has a strong relationship with road hierarchy and a lesser degree with land uses. The maps show that most of the urban area studied has some level of contamination.

Keywords: environmental magnetism, geostatistics, urban dusts, urban pollution, land use, road hierarchy.