The role of gypsum in bioremediation; recovery of ecosystem functions and services of pollutes soils

Resumo

Soil is one of the main providers of environmental functions and services, its productivity being one of the most essential services for human survival and development. Nevertheless, anthropogenic activities such as mining, may seriously degrade it, causing relevant health and ecological hazards. In this sense, soil acidification, salinization and pollution are a great concern worldwide, for which many degraded soil ecosystems would require assisted natural remediation. The aim of this thesis is to assess the role of gypsum mining spoil as an amendment of soils affected by acidification, salinization and Potentially Harmful Elements (PHEs), in order to revalue this mining waste material while assisting the natural remediation of degraded soils and their associated plant communities. The study area is located in the Guadiamar Green Corridor (GGC, Southern Spain), home to one of the worst European ecological disasters that has ever occurred. In 1998, the Aznalcóllar pyrite mine pond breached and released acidic waters and tailings highly polluted with PHEs. Thereupon, multiple cleaning and rehabilitation activities were undertaken in the area to guarantee the population’s safety and its complete recovery over time. However, many years following the disaster, there are still numerous remnant spots of polluted soils where vegetation cannot even germinate.