Papel de los coloides en la dispersión de arsénico en suelos de mina de Madrid

Gómez-González, Miguel Ángel ; Garrido, Fernando ; Laborda, Francisco (Universidad de Zaragoza) ; Villalobos, Mario ; Bolea, Eduardo (Universidad de Zaragoza) ; Gómez-Arce, Paula ; Aguilar-Carrillo, Javier

Resumen: In recent years, elevated concentrations of arsenic (As) have been detected in the Tertiary detrital aquifer of Madrid. A significant number of areas where waste from old mining operations, rich in metals and metalloids, accumulate may partially explain contamination events by toxic elements. In these environments, colloidal particles can act as nanovectors for the dispersion of As, enhancing its migration and contamination of surrounding soils. This work studies the mobilization of As-rich colloids from a waste zone of an old mining operation in the Community of Madrid. These wastes, mainly composed of arsenopyrite [FeAsS] ([As] = 0.2 g kg-1), are deposited near a natural stream and exposed to environmental conditions. In order to follow the mobility of As-rich colloids, the combined techniques of asymmetric flow field flow fractionation and inductively coupled plasma mass spectrometry (AF4-ICP-MS) are used to obtain the size distribution of the colloidal fraction and associated As, while X-ray absorption spectroscopy (XAS) techniques are utilized for the study of the chemical speciation of As in the solid phase. In addition, geochemical modeling allows prediction of the thermodynamically favored phases in each of the studied areas. The mobilization of colloidal As from mining waste to water and soil located up to 1 km from the source of contamination is described. The essential role of colloidal Fe oxyhydroxides as As mobilizing nanovectors is also highlighted.

Idioma: Español

DOI: 10.3989/egeol.45761.1143

Año: 2025

Publicado en: Estudios Geológicos 81, 2 (2025), 1143 [18 pp.]
ISSN: 1988-3250

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Química Analítica (Dpto. Química Analítica)