LEAD IN URBAN SOILS: A CASE STUDY FROM A TERRE HAUTE COMMUNITY GARDEN

In many urban areas, community gardens have become a popular local resource for residents. However, many urban areas also battle persistent soil contamination by metals such as Pb resulting from a long history of high traffic volumes, industry, and coal combustion. The ISU Community Garden includes 128 individual plots of different sizes that are used by community residents to grow a variety of vegetable and other plants. The purpose of this research project was to document Pb levels in the ISU Community Garden in Terre Haute, IN using both hand-held XRF and ICP-OES technology. 692 samples were collected with spacing at approximately 2 meter increments in a grid type pattern throughout the entire 128 individual plots contained within the garden at < 5 cm depth. Field samples were initially analyzed with a portable energy-dispersive XRF. Initial XRF data revealed levels below detection to a high of >800 ppm Pb. Recommended Pb levels for gardening should be less than 200 ppm. The majority Pb levels >200 ppm are contained within plots found in the northwest quarter and along the extreme eastern edge of the garden. Ongoing research includes reanalyzing dried samples with the XRF to evaluate the impact of moisture content on Pb concentrations. In addition, a subset of sample will be sieved to <106 um and ashed for LOI then acidified for analysis via ICP-OES and XRF to evaluate the impact of sample processing on XRF measurements.