Antimonate sorption in soils increases with ageing

Abstract

AbstractIt is unclear to what extent sorption of antimony (Sb) in soils occurs over long time scales. This study was set up to monitor slow reactions (7 days to 6 months) of Sb in Sb(V)‐spiked soil samples during aerobic incubation. The solid–liquid distribution coefficients (KD) increased by factors of 3 to 6 between 7 and 190 days after spiking, depending on the soil. This increase in the KD value, hereafter named the Sb ageing factor, increased with increasing amorphous iron and aluminium hydroxide concentration and decreasing pH of the soil samples. Finally, ageing factors were highest in topsoils and could be important in preventing Sb from migrating downwards into groundwater bodies.Highlights Quantification of antimonate ageing in soils. Topsoils could prevent downward leaching of Sb in the long‐term. Ageing of Sb increased in soils with increasing amorphous iron and aluminium hydroxide concentration and decreasing pH. Slow sorption reactions reduce Sb mobility in soils.