Accumulation of Mercury and Other Potentially Toxic Elements in Edible Plants Associated with Soil Contamination in Historic Mining Areas

The Almadén area (Ciudad Real, Spain) is one of the world’s most important historic mercury mining districts, where centuries of extraction and processing have generated a persistent environmental legacy. Owing to its high toxicity, volatility, and long residence time in the environment, mercury remains a critical contaminant, particularly with respect to its mobility in soils and its transfer to biota and the human food chain.

In this context, the investigation of mercury and other potentially toxic elements in edible plant species is of particular relevance, as it provides insight into metal uptake mechanisms, bioaccumulation processes, and the potential environmental and health risks associated with plant consumption. Edible plants can act as effective bioindicators of soil contamination, offering valuable information on metal mobility, bioavailability, and exposure pathways affecting both ecosystems and human populations.

The main objective of this study is to assess the concentrations and distribution of mercury and other potentially toxic elements in edible plants from the Almadén area and to examine their relationships with soil physicochemical properties, in order to elucidate metal transfer processes within the soil–plant–atmosphere system, with special emphasis on Hg. Representative soil and plant samples are jointly analyzed, allowing comparisons among different plant species and sampling locations and enabling the identification of key factors controlling metal accumulation.

The results provide a robust basis for evaluating the risks associated with metal contamination in edible plants, identifying areas of increased environmental impact, and improving the environmental characterization of one of the most significant historic mining regions worldwide. In addition, this study contributes to the identification of plant species with a high capacity for metal accumulation, supporting the development of future strategies for environmental management, phytoextraction, and phytoremediation in contaminated soils.