Plants and Poultry Waste Can Immobilize Lead in Soil, Study Says
Yohey Hashimoto, a scientist at Mie University in Japan, has demonstrated the use of poultry waste amendment in combination with plant growth to immobilize soil lead (Pb) and restore degraded vegetation in shooting range sites.
He measured Pb speciation of the soil using X-ray absorption spectroscopy at SPring-8, the world largest synchrotron radiation facility in Japan, and soil enzyme activity along with the changes in soil Pb immobilization. Results from the study were published in the July-August 2009 issue of the Journal of Environmental Quality. The research was also presented in Houston, Texas at the Annual Meetings of the Soil Science Society of America last year.
Lead speciation and enzyme activity were measured in shooting range soils treated with a grass plant and/or poultry waste in a large column setting. The research is targeted at the changes in Pb speciation along with enzyme activity and downward solute transport. As well as an understanding of metal solubility and transport, enzyme activity can become a more important factor when the goal of soil remediation program includes ecological restoration. The use of amendment with less adverse impacts on soil biological properties could be a prerequisite for a comprehensive and long-term restoration program of shooting range areas.
The study revealed that the amendment reduced the proportion of cerussite (PbCO3) and Pb-organic complexes and transformed them into a more geochemically stable species of chloropyromorphite [Pb5(PO4)3Cl] with 30 to 35 percent of the total Pb species. Applications of plant and amendment decreased downward Pb transport and increased activities of dehydrogenase and phosphatase in the surface soil.
The full article is available for a limited time; view the abstract at Journal of Environmental Quality, is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy, Crop Science Society of America, and the Soil Science Society of America.