Effects of waterlogging on the solubility of antimony and arsenic in variously treated shooting range soils

Abstract

This study examined a release of two metalloids: Sb and As into pore water from five shooting range soils under oxidized and waterlogged conditions, in a 140-day incubation experiment. The total concentrations of Sb and As in soils were in the ranges: 4.15–89.6 and 2.23–9.22 mg kg−1, respectively. Soils were treated with green waste compost and deferrisation sludge prior to incubation. Additionally, the effects of treatment with acid and lime were examined. Pore water was collected 5 times with MacroRhizon suction samplers and examined on Sb and As concentrations. Antimony speciation in pore water involved Sb(III) and Sb(V) which were assayed by ICP-MS-HCLP. Additionally, five operationally defined fractions of Sb and As in soil solid phase were determined by sequential extraction before and after incubation. Data showed that waterlogging considerably reduced final Sb concentrations in pore water, irrespectively of the kind of pre-treatment, except for a temporal increase in Sb solubility in two soils. On the contrary, As was usually more intensively released under anoxic conditions, particularly from compost-treated soils. The concentrations of Sb(III) were negligible in pore water of oxidized soils, while their share in pore water of waterlogged soils was considerable and tended to increase with prolonged incubation. The highest concentrations of Sb(III) in pore water were found in waterlogged acid-treated soils, and also in limed soils. The mechanisms involved in the changes of Sb and As solubility were discussed. Sequential extraction did not provide satisfactory results consistent with hypothesized processes running in waterlogged soils.