Speciation and bioavailability of selenium and antimony in non-flooded and wetland soils: A review

• Published in: Chemosphere (Oxford) 2014-09, Vol.111, p.366-371
• Main Authors: Nakamaru, Yasuo M., Altansuvd, Javkhlantuya
• Format: Article
• Language: English
• Subjects: Adsorption; Antimony; Antimony - analysis; Antimony - chemistry; Applied sciences; Bioavailability; Biological and physicochemical properties of pollutants. Interaction in the soil; Exact sciences and technology; Hydrogen-Ion Concentration; Non-flooded soil; Oxidation-Reduction; Pollution; Selenium; Selenium - analysis; Selenium - chemistry; Soil - chemistry; Soil and sediments pollution; Soil Pollutants - analysis; Soil Pollutants - chemistry; Speciation; Wetland soil; Wetlands; X-Ray Absorption Spectroscopy
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2014.04.024

•Speciation and bioavailability of Se and Sb in non-flooded and wetland soils are reviewed.•In non-flooded soil, Se availability is mainly controlled by metal oxy-hydroxides.•In wetland soil, Se bound to organic matter is relatively important.•In non-flooded soil, most Sb is sorbed or deposited as insoluble forms.•In wetland soil, Sb availability can increase with reduction of Fe and Mn oxides. Studies on the sorption behaviors of selenium (Se) and antimony (Sb) are reviewed. Both Se and Sb chemical speciation can be controlled by pH and redox potential, and both of them are likely to be sorbed onto oxy-hydroxides of aluminum, iron or manganese in soils. For agricultural soils especially, there are important physico-chemical and biological differences between non-flooded and wetland soils. Se forms Se(VI), Se(IV), Se(0), Se(-II), and organic Se species at soil pH and redox conditions. Under non-flooded conditions Se solubility is governed by an adsorption mechanism onto metal oxy-hydroxides rather than by precipitation and dissolution reactions; however, for the conditions of wetland soils, it can be expected that Se(0) and organic matter-bound Se play an important role. For Sb, in the soil environment, the dominant Sb forms are Sb(III) and Sb(V). Under aerobic soil conditions, Sb(III) is likely to be oxidized to Sb(V), and the dominant sorbed Sb species should be Sb(V). Under reducing conditions Sb mobility should be lower than under oxidizing conditions due to the lower mobility of Sb(III); however, reduction of Fe and Mn oxides could lead to dissolution of Fe and Mn-bound Sb. This indicates that the risk of Sb contamination to the food chain could be increased in wetland systems.