Effects of three amendments on extractability and fractionation of Pb, Cu, Ni and Sb in two shooting range soils.

Contamination of shooting range soils with toxic trace elements, in particular Pb and Sb, is of increasing environmental concern worldwide. We studied the extractability of Sb, and other metals in two shooting range soils: a calcareous soil (pH 8) with low organic carbon (0.5%) and a non-calcareous soil (pH 6.3) with elevated organic carbon content (5%). Both soils contained total concentrations of around 500 mg kg(-1) Pb, 65 mg kg(-1) Cu, 100 mg kg(-1) Zn and 20 mg kg(-1) Sb. We tested the effects of Ca(OH)(2), phosphate and sodium humate amendments on metals and Sb extractability. Extracts with H(2)O and NaNO(3) contained 0.02-0.05% of the total Zn and Pb; 0.1-0.5% of total Ni and Cu and approximately 1% of total Sb. Sequential extraction procedure of Zeien and Brümmer resulted in similar percentages for the sum of the two most labile fractions (F1+F2) in two soils: 10% Pb, and 15-20% Sb. Water and NaNO(3)-extractable Sb concentrations increased after phosphate addition, but were not affected by the addition of sodium humate. The results show that leaching of Sb from shooting ranges into ground and surface waters may generate a serious environmental risk under widely different soils conditions.