Distribution of Lead in an Urban Soil: A Case Study and Implications for Potential Remedial Options

Soil has been shown to be a significant risk for exposure to Pb in urban environments. In this study, we investigate a single residential property in Rochester, NY, USA. Using a combination of field portable XRF and selective sequential extraction techniques, 3-D distribution of Pb in soil was determined for the property. Result show substantial translocation of Pb downward through the soil profile, extending into the soil B horizon with the highest concentration of 1679 mg kg-1 found in the 5 to 10 cm depth interval. Sequential extraction results show the majority of Pb to be associated with organic matter and crystalline oxyhydroxides. Initial experiments investigating facilitated leaching found that strong chelating agents could remove appreciable amounts of Pb from the soil, suggesting both possible mechanisms for natural migration or for potential remedial options.