A critical assessment of soil amendments (slaked lime/acidic fertilizer) for the phytomanagement of moderately contaminated shooting range soils

Purpose: The effects of the addition of an acidic fertilizer solution and/or slaked lime (5.5 g Ca(OH)2 kg-1) on a slightly acidic shooting range soil (pH 6.1, % organic carbon 5.4) with moderate metal (e.g., 620 mg kg-1 Pb) and metalloid (17 mg kg-1 Sb) concentrations on metal and Sb solubility and plant accumulation were investigated. Materials and methods: In a pot experiment, we grew Plantago lanceolata, Lolium perenne and Triticum aestivum. The pH, dissolved organic carbon (DOC), and metal and Sb concentrations in the leachate were monitored. Results and discussion: The addition of slaked lime increased the soil pH from 6.1 to 7.2 and the DOC from 100 to 300 mg l-1. In contrast to Sb, we found a correlation between DOC and soluble Cu concentrations. The addition of the acidic fertilizer significantly increased Mn- and Pb-NaNO3 extractable concentrations. Slaked lime decreased at first, Pb-, Mn- Ni- and Zn-NaNO3 extractable concentrations, but with time, these concentrations increased. Metal accumulation in shoots was in general low. The highest concentrations were obtained in shoots of L. perenne for Mn (135 mg kg-1 DW). Spikes of T. aestivum accumulated more Cu, Mn, Ni and Zn than shoots. Grains of T. aestivum had higher Zn concentrations (up to 37 mg kg-1) than spikes and shoots (up to 22 and 19 mg kg-1, respectively). Antimony concentrations were always below 2 mg kg-1 for the three species studied. Conclusions: Under these growing conditions, these three plant species showed to be suitable for the phytomanagement of moderately contaminated shooting range areas. © 2012 Springer-Verlag.