Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 2001
Publication Date: November 25, 2002
In-situ remediation techniques are prospective technologies in which materials are incorporated into soil to alter contaminant geochemistry, making the contaminants less water-soluble, less mobile, and less bioavailable to both ecological and human receptors. A cooperative field study was initiated in the spring of 1997 in Joplin, Missouri USA, on a vacant city lot in proximity to a former lead smelting facility. The site was selected based on many factors, including total soil-lead concentration, size, and long-term accessibility of the site. This site soil was not initially toxic to plants, however. Treatments evaluated included phosphorus (P) added in the fertilizer form of Ca(H2PO4)2, the acid form of H3PO4, and the mineral form of rock phosphate (hydroxyapatite). Rates of addition ranged from 0.1 to 3.2% P. Several municipal biosolid composts were also tested both with and without P additions. Treatment efficacy compared to control, untreated plots was evaluated in several ways, including: a chemical extraction technique to simulate lead bioavailability from direct ingestion of soil particles and by the amount of metals (e.g., lead, zinc, and cadmium) translocated from the soil to the tops of plants growing in the contaminated soil. Both of these endpoints were significantly lower in several treatments compared with control plots. Consistently, the most effective treatment was the 3.2% P addition as Ca(H2PO4)2. Lead, zinc, and cadmium concentrations in the plant tissue were significantly reduced as a result of certain treatments.