Elemental characterization of edible plants and soils in an abandoned mining region: assessment of environmental risk

The chemical concentrations of 11 elements in 6 species of edible plants grown in 7 soils, developed in different gossanous materials of the abandoned mine area of Sao Domingos, in southern Portugal, was measured by energy dispersive X-ray fluorescence. The total fraction of elements in the soils from which the plants were sampled, was measured, using wavelength dispersive X-ray fluorescence. The elemental content in bioavailable fraction was obtained by using three different leaching tests: DIN 38414-S4, 1 M ammonium acetate and 0.005 M DTPA. Leachates were analyzed by Induced Coupled Plasma—Optical Emission Spectrometer (ICP-OES) and Induced Coupled Plasma—Mass Spectrometer (ICP-MS). The mineralogy of the same soils was evaluated by X-ray diffraction to identify the species present. The results show that levels in plants can be hazardous especially for Pb and As. Important concentrations of Fe and K were also observed. A different uptake was observed in the several plants for the different elements. The highest assimilation of metals was observed in sampling points containing soluble sulfate salts. Copyright © 2011 John Wiley & Sons, Ltd.