Studies on speciation of antimony in soil contaminated by industrial activity

Antimony is a toxic trace element of growing environmental interest due to its increased anthropogenic input into the environment. Very little is know n about the chemical and biological behavior of antimony compounds in soils and sediments. Three soil samples with substantially elevated Sb concentra tions (area contaminated by extensive industrial use of Sb compounds), and a soil standard reference material have been analyzed by using conventional single and sequential extraction procedures in order to get information ab out the chemical forms and availability of Sb in the soil. The antimony con centrations in the extraction solutions were determined by inductively coup led plasma mass spectrometry (ICP-MS). Additionally, Sb(III) and Sb(V) were determined in some extracts by using high-performance liquid chromatograph y coupled on-line to the ICP-MS (HPLC-ICP-MS). The total Sb concentrations were in the upper mg kg(-1) range, but only sma ll amounts were found to be easily available from the soils. The main antim ony was bound to relatively immobile Fe and Al oxides. Substantial amounts were also found in the alkaline and EDTA extracts, indicating association o f Sb to organic substances. Although contamination was caused by the produc tion of Sb(III) compounds, Sb(III) was not dedected in any of the extracts. The behavior of Sb(III) las Sb(III) tartrate and Sb2O3) and Sb(V) las Sb(O H)(6)(-)) added to the soil samples was investigated in detail.