Elemental characterization of plants and soils in Panasqueira tungsten mining region

Mining activities represent a current source of pollution due to the large release of trace elements from mineral particles into the soil, atmosphere, and ecosystems. In active or abandoned metal-mining areas, direct discharge from mining deposits is one of the most common processes of contamination.In this work, we calculated the elemental concentrations of plants, edible for cattle, which might contain high values of toxic elements, such as As, Cu, Zn, and W, originated from mining exploitation, especially wolframite. Several species of plants originating from the same contaminated place, close to the mine, were the subject of our study in order to compare the uptake of harmful elements, from the contaminated soils, in the different plants. We have used the energy-dispersive X-ray fluorescence technique to perform the analysis and quantification of the elements present in the collected samples. The quantification was based on the fundamental parameters method for plants and on the WinAxil compare mode using a standard reference material, for soils. Calibration against a series of standard samples has been carried out.A comparison between contaminated and control samples, within the same species, was performed. The contamination of the two mining wash sites is assessed by comparing the elemental concentration of several plants in these places. Elemental content in soils was investigated, and a comparison between elemental levels in plants was performed.High concentrations of tungsten were found near the new wash site. Arsenic was found throughout the area in concentrations many times higher than those recommended by the World Health Organization.