Use of spinach, radish, and perennial ryegrass to assess the availability of metals in waste foundry sands

Plant uptake is a major pathway by which toxic metals can enter the food chain. In this laboratory study we grew spinach, radish, and perennial ryegrass on sand blends containing 50% waste foundry sand (WFS) to assess the availability of Al, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, V, and Zn. The WFSs utilized in this study were from aluminum, iron, and steel foundries. Although there were differences in the amounts of metals accumulated by the various plant species, excessive amounts of heavy metals were not taken up, regardless of WFS treatment. In spinach and radish, B, Cu, Fe, Mn and Zn were found to be within or close to the sufficiency range for agronomic crops. In ryegrass cuttings at 27, 57, and 87 days, Cu and Zn were within sufficiency ranges, but plants were Fe deficient and contained elevated concentrations of B, Mn, and Mo. Data from this study will be useful for state regulatory agencies interested in developing beneficial use regulations for WFSs.