Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2006
Publication Date: 9/12/2006
Citation: Dungan, R.S., Dees, N.H., Green, C.E. 2006. Plant Availability of Metals in Waste Foundry Sands. Meeting Abstract. p. 230.
Technical Abstract: Foundries in the United States generate several million tons of waste sand each year. These sands are no longer suitable for metalcasting processes, and about 90% are discarded in landfills. However, the majority of these waste foundry sands (WFSs) qualify as non-hazardous industrial waste and the possibility exists for them to be beneficially reused. One potential beneficial reuse of WFSs is in value-added products such as horticultural soils, topsoils, potting soils and turf mixes. A food chain risk for metals must be conducted, however, before many states will consider allowing WFSs to be used in value-added products. In this experiment we assessed the uptake of metals (Al, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, V, and Zn) by spinach (Spinacia oleracea), radish (Raphanus sativus) and perennial ryegrass (Lolium perenne). The plants were grown in sand culture containing 50% WFS and maintained with full-strength Hoagland’s solution. A total of six sands were tested: two iron ‘green sands’ (clay-bonded sand), two aluminum green sands, and two steel sands that used a phenolic urethane no-bake binder. The radish were harvested at 27 days, spinach at 39 days, and perennial ryegrass at 27, 57 and 87 days. 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 particular, Cd, Co, Cr, Pb and V were not detected in the majority of plant tissues, and when detected they were at the lowest concentrations of any of the elements measured. 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 levels of B and Mn. Data from this study will be useful for state regulatory agencies interested in developing beneficial use regulations for WFSs.