Saturday, 15 July 2006

Lead Distribution in Urban Residential Soils of Portland, Maine.

Samantha Langley-Turnbaugh and Travis Wagner. University of Southern Maine, 37 College Ave., Dept. of Environmental Science, Gorham, ME 04038

Many soils in the Greater Portland area are contaminated with high concentrations of lead. The presence of lead is due to lead-based paint, leaded gasoline emissions, and past industrial activities. Lead exposure disrupts the development of the nervous system, causing delays in growth and learning disabilities. This study was conducted to determine the soil lead distribution throughout Bayside, Parkside and West End neighborhoods of Portland, Maine. Bayside is a low-income, racially and ethnically diverse neighborhood and is home to the largest number of refugees and immigrants of any other neighborhood in Portland. Parkside is the most densely populated and ethnically diverse square mile of Maine, with over 8000 residents. 25% of the Parkside population is living below the poverty level. The West End neighborhood was developed after Portland's “great fire” in 1866, and approximately 84% of the housing was built before 1950. Thus, lead poisoning is a great concern in Portland, and cases of severely poisoned children have been identified. We sampled 105 residential properties and collected 1096 surface soil samples according to EPA's Lead Safe Yard Protocols. Soils were extracted using EPA 3050b and analyzed on an ICP for Pb, Cd, Ni, Zn, Cr, Co, Cu, As, Mn, and Hg. Concentrations of most metals were below EPA critical limits, but lead concentrations varied from 32 mg/kg to 28,000 mg/kg. Lead concentrations were then mapped using GIS. The spatial distribution maps show lead distribution patterns that are currently being analyzed for relationships with past industrial activities, proximity to major roads, and prevailing wind patterns.

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