Comparison of three sequential extraction procedures for arsenic fractionation in highly polluted sites

Natural variation of arsenic fractions in soils of the Brazilian Amazon

“…Yet, As is found more abundantly in argillaceous sediments (up to 13 mg kg −1 ). Anionic forms, AsO 2 Many sequential extraction procedures (SEP) can be used to extract chemical fractions of trace elements in soil (Wan et al, 2017;He et al, 2013). These methods classify trace elements in soil into different operationally-defined fractions with increasing metal binding strength (Wan et al, 2017).…”

“…Anionic forms, AsO 2 Many sequential extraction procedures (SEP) can be used to extract chemical fractions of trace elements in soil (Wan et al, 2017;He et al, 2013). These methods classify trace elements in soil into different operationally-defined fractions with increasing metal binding strength (Wan et al, 2017). Soil chemical extractions for soluble and available As can help understand the element's dynamic chemical behavior and its possible entrance into the food chain.…”

“…Many extractants can be used for this purpose, for example, the soluble fraction can be extracted using water (water-soluble) (Wenzel et al, 2001; Baroni et al, 2004;Jiang et al, 2014;Wan et al, 2017). This fraction contains water-soluble species such as free arsenate, and weakly adsorbed species, representing the most mobile and potentially the most bioavailable As species in the environment (Wan et al, 2017). Additionally, the soluble fraction can be also extracted using inorganic salts such as KCl (Kim et al, 2003) and KNO 3 (Alam et al, 2007).…”

“…Another relevant fraction of As -the available fraction -is not well defined in the literature in terms of method of extraction, but would be better classified as the As retained in the solid phase interacting with the soil solution and occupying exchangeable sites as diffuse ion or as outer-sphere complexes (Van Herreweghe et al, 2003) and can be extracted by using Na 2 HPO 4 (Kim et al, 2003), MgCl 2 (Jiang et al, 2014), CH 3 COOH (Wan et al, 2017), (NH 4 ) 2 SO 4 (Wenzel et al, 2001) and KH 2 PO 4 (Thinh et al, 2018) among others.…”

Distribution of arsenic in an argillaceous sample using sequential chemical extractions: application to the Hydrogeological Experimental Site of Poitiers (HESP)

“…In sediments, arsenic can be linked to several solid phases that might be solubilized under certain changes in groundwater conditions causing the release of the associated arsenic through desorption or dissolution [4]. Hence, in order to predict arsenic's mobility and bioavailability, it is of great importance to determine its distribution and chemical associations in sediments rather than only measuring its total concentration [5].…”