Morais ultramafic complex: A survey towards nickel phytomining

Ultramafic areas are critical for nickel (Ni) phytomining due to the high concentration of this element in their soils and the number of hyperaccumulators they harbor. The aim of the present study was to evaluate the potential of the Morais massif, an ultramafic area in Portugal, for phytomining using the hyperaccumulator species Alyssum serpyllifolium subsp. lusitanicum. Soil samples and A. serpyllifolium specimens were collected in four locations of the Morais massif. After determination of Ni concentrations in the samples, the results show that soil pseudo-total Ni concentrations in sites number 1 and 2 are significantly higher than in the soil samples collected in the other two locations, with 1918 and 2092 mg kg^-1, respectively. Nickel accumulation is significantly greater in the aerial parts of plants collected at sites 1, 2, and 4, presenting Ni harvestable amount means of 88.36, 93.80, and 95.56 mg per plant, respectively. These results suggest that the sites with highest potential for phytomining are sites 1, 2, and 4. A nickel agromining system in these locations could represent an additional source of income to local farmers, since ultramafic soils have low productivity for agriculture and crop production.