Elemental Concentration in Serpentinitic Soils over Ultramafic Bedrock in Sierra Bermeja (Southern Spain)

Abstract

Although the presence of potentially toxic metals in soils is normally associated with human soil pollution, these elements also appear naturally in environments in which the lithological base contains ultramafic rocks such as peridotites. Serpentinitic soils tend to develop on substrates of this kind, often containing metals with few or no known biological functions, which in some cases are toxic for most plants. This study assessed the level of potentially toxic metals and other elements in an endorheic basin discovered in Sierra Bermeja (Southern Spain), one of the largest peridotite outcrops on Earth. In this location—of particular interest given that basins of this kind are very rare on peridotites—six geomorphoedaphic sub-units on three different substrates were identified. The distribution of microelements in these sub-units was analyzed, and stratified random sampling was performed to identify the major ions with essential functions for living organisms and the potentially toxic metals. The lowest values for macronutrients appeared in the soils formed on ultramafic materials. When analyzing the load of potentially toxic metals, no significant differences were detected between the soils formed on serpentinite and peridotite substrates, although different values were obtained in the soils formed over acidic rocks.

Metal accumulation by Alyssum serpyllifolium subsp. malacitanum Rivas Goday (Brassicaceae) across different petrographic entities in South-Iberian ultramafic massifs: plant-soil relationships and prospects for phytomining

“…Although bioavailability was not studied in our study, the concentration of Ni was similar across the studie d petrographic entities. The soil samples collected on Bh, Bl and Ms massifs showed the highest concentration of Ni in our study which were higher in comparison with other studies on different ultramafic soils (Ghaderian et al 2007;Bani et al 2013;Morais et al 2015;Álvarez-López et al 2016;Romero-Freire et al 2018;Mišljenović et al 2019).…”

Morais Ultramafic Complex: A Survey towards Nickel Phytomining

“…All soil samples exhibit an approximately neutral to slightly acidic pH (6.8-6.4), typical of serpentine soils that are characterized by a pH that ranges between 6 to 8 [32]. The electrical conductivity values are low, meaning that there are no dissolved salts [33]. As expected for serpentinite soils, the Morais massif presents high concentrations of Mg, Ni, and Cr (Figure 2), as well as a low Ca:Mg ratio.…”

Trace and ultratrace elements in spinel subgroup minerals of ultramafic rocks from the Voltri Massif (NW Italy): the influence of microstructure and texture

“…SSMs can have a significant impact on the environment and human health since they may contain and, hence, they may be the source of potentially toxic elements (PTEs), which can be released into soils and circulating waters during weathering and pedogenesis. This process can be particularly significant in ultramafic soils, deriving from peridotites and serpentinites, which commonly have high concentration of PTEs, particularly Cr, Ni, and Co (e.g., Duivenvoorden et al, 2017;Romero-Freire et al, 2018;Fornasaro et al, 2019;Marescotti et al, 2019).…”