The Enrichment of Potentially Toxic Elements in the Iberian Pyrite Belt's Abandoned Mines: Geomaterials as Purpose for Their Remediation

Abstract

The Iberian Pyritic Belt (IPB), a well-known volcanogenic massive sulfide (VMS) province with important mining activity history, had, in the last decades, several mines ceasing their mining activities and becoming abandoned. The mining area of Caveira, in Grândola (Portugal), located in the western part of the IPB and the mining complex of Trimpancho (Spain), located in the eastern part of the IPB, both stopped operating in the 1960s and have been under our scope of study for the last 3 years due to poor management of the waste piles, with no policies to contain contaminants. High values of Potential Toxic Elements (PTE), such as Cu, Pb, Zn, Hg and As, in both mining areas, and their surroundings, led to serious focus of our studies in those regions, thus planning to test and apply geomaterials for containment of PTE’s, from the mine tailings, and carry out trials for remediation of the surrounding mining areas. In 2022, an anomalously dry year, and 2023, sediment samples were taken from the watercourses under mining influence at both sites, and from areas upstream (geochemical background), with the aim of studying the Index of Geochemical Load (IGL) and the Enrichment Factor (EF) of the sediments in these metals at the interface with the water column, and to study metals in their most leachable forms and therefore most likely to contaminate downstream watercourses.