Recovery and leachability of antimony from mine- and shooting range soils

Little is known about the problem of soil contamination with antimony in Poland. Soil samples examined in this study represented two different kinds of Sb-enriched areas: military shooting ranges and historical mining sites in south-western Poland. Total Sb concentrations in soils, determined after fusion with lithium borate, were in the range 17.3-427 mg kg-1. The amounts of Sb recovered as “near total concentrations” were determined after soil digestion with concentrated nitric acid and aqua regia. The study confirmed very low recovery of Sb in soils digested with nitric acid (mean 20.9% of total), significantly lower in mine soils (7.6 ±3.4%) than in shooting range soils (34.2±17.5%). Aqua regia digestion proved to ensure satisfactory recovery of Sb, circa 90% of its total concentrations, independently of the soil origin. Additionally, toxicity characteristic leaching procedure (TCLP), developed by the US EPA, was applied to determine leachability of Sb from soils. The concentrations of Sb in TCLP leachates: 0.001-0.281 mg L-1, remained at a level considered as ecologically safe, but considerably exceeded the threshold values for underground and drinking water. The amounts of Sb leached from the shooting range soils in the TCLP procedure, expressed as percentage of total Sb, were determined as 6.2±2.0%, i.e. significantly higher compared to mine soils (0.74±0.42%). These results should be considered as a premise for further risk- and remediation-oriented examination of shooting range soils.