Jemrest




Home \| Instructions to Authors \| SASE \| Editorial Board \| Articles \| Subscriptions \| Conference

Abstract

Yang, J. and Xi Tang. 2008. Ecological risk assessment of metal-contaminated soils using a bacteria-based assay. JEMREST 5:00-00

Elevated metal contaminants in soil are a threat to human health and environment. This study was conducted to modify a bacteria-based assay appropriate for eco-toxicity assessment of a soil in an effort to evaluate ecological risk reduction of metal-contaminated soil by in situ phosphate treatment. A bacteria-based toxicity test that has been primarily used for water quality assessment was evaluated under various parameters such as soil: solution extraction ratio, pore size of filter paper, and time of measurement. Two soils (urban and mine soil) containing about 4000 mg Pb kg^-1 that had been treated with soluble phosphate were collected from the Jasper County Superfund Site, southwest Missouri. Waters and control soils were also sampled and analyzed for quality control and comparison of treatment effects. Results showed that measurements of the bacteria assay varied with the soil: solution extraction ratio, pore size of filter paper, and time of measurement, and the procedures that used higher than 1:4 ratio, 0.45 um pore size, and measured 3d after extraction would provide a stable and consistent result. Soil measurements were comparable with water assessments. This study illustrated that the modified bacteria-based test would be applicable for soil eco-toxicological assessment and soluble phosphate treatments would effectively reduce the ecological risks of metal-contaminated soils through immobilization mechanisms.