Effect of bone meal (calcium phosphate) amendments on metal release from contaminated soils - a leaching column study

Metal-contaminated soil may be remediated in situ by the formation of highl y insoluble metal phosphates if an appropriate phosphorus (P) source can be found. Leaching column experiments have been carried out to assess the sui tability of bone meal as such a source. Bone meal additions reduced metal r elease from a contaminated soil, increased soil and leachate pH and decreas ed soil leachate toxicity. Minimal P leaching occurred from the soil. The d ata are consistent with a proton consuming bone meal (calcium phosphate) di ssolution reaction followed by the formation of metal phosphates. Although, no metal phosphates were observed to form using X-ray diffraction or scann ing electron microscopy this could be due to their low concentration. Relat ively low (1:50 bone meal:soil) concentrations of fine (90-500 mum) bone me al would appear to be an effective treatment for metal-contaminated soils. (C) 2001 Elsevier Science Ltd. All rights reserved.