Indirect elemental speciation inferences in soil are possible through leaching or fractionation and extraction techniques. While single and sequential soil extraction approaches come with various interpretation and application difficulties, they will remain in use until direct measures of speciation (e.g. HPLC-ICP-MS) become much more commonplace and affordable, and subsequently widely available to both research and routine analysis laboratories.

Because arsenic (As) is a group V element with oxyanionic aqueous species As extractions have been developed from repeatedly verified phosphorus (P) schemes, with some success in estimating As bioavailability from such fractionation. In this work a modified As and P based sequential extraction is proposed and used on floodplain soils enriched in As and antimony (Sb) to determine the applicability of extrapolating such a scheme for Sb fractionation, and estimation of Sb mobility. The relative efficacy of extractants for Sb removal from the soil was compared and contrasted with As and P fractionation. The importance of the oxalic acid- ammonium oxalate step as a target for non-crystalline oxide and hydroxide phases in these acid soils was stressed.