The problematic of soil contamination by industries in a protected area in Portugal

Understanding the environmental legacy surrounding abandoned industrial sites, once powered by fossil fuels and operated in times of less stringent environmental regulations, is crucial today. This issue is especially pertinent in regions that have since become protected areas. Cabo Mondego, recognized internationally for its geological diversity, designated as a National Monument of Portugal, and included in the Atlantic Geopark project, represents such a region due to its history of potentially degrading activities associated with coal mining and an industrial complex focused on cement and lime production. To ensure the sustainable use of this protected area, it is essential to assess soil health. In this study, fifty soil samples were collected from areas bordering the decommissioned industrial complex and coal mining remnants. The research detected contaminants, their geochemical associations, and potential sources. The evaluation included comparisons with reference values, assessment of the contamination severity, multivariate data analysis, and spatial distribution analysis. Three primary anthropogenic sources of soil contamination were identified: (1) atmospheric emissions from the industrial complex, primarily linked to As and Se contamination, with additional samples showing contamination by Ni, V, and Cr; (2) localized coal mining waste disposal, associated with As, Mo, and Se contamination; and (3) isolated fuel contamination, indicated by elevated Pb levels. Additionally, the study suggests that geogenic sources contribute to the elevated As and U levels in soils with specific geological characteristics. This characterization of potential toxic contaminants in Cabo Mondego enhances the understanding of the region's vulnerabilities and highlights the importance of its protection.