Thursday, 10 November 2005 - 8:30 AM
327-2

Phytoremediation of Lead Contaminated Soil in Portland, Maine.

Charity West and Samantha Langley-Turnbaugh. University of Southern Maine, Department of Environmental Science, 37 College Ave, Gorham, ME 04038

Portland, Maine has the thirteenth oldest housing stock in the U.S. Manufacturing and industry were prevalent in the 1800's and a significant percentage of the homes were built prior to the 1950's, before regulations on the use of lead in the construction of homes and lead in paint. Thus, lead poisoning is a great concern in Portland, and cases of severely poisoned children have been identified. Recent research has shown that the soils in three neighborhoods in Portland were highly contaminated, with soil lead concentrations varying from 32 mg/kg to 28,000 mg/kg. The purpose of this research was to test the ability of phytoextraction to reduce soil lead concentrations in contaminated areas. Ten garden sites were chosen over a 3 year period for phytoextraction experiments, using Spinacia oleracea. Soils were collected before and after harvest and analyzed for total and plant available lead, organic carbon, texture, and pH. The S. oleracea was analyzed for total lead in roots and shoots. The results indicated that S. oleracea absorbed Pb and root concentrations were always higher than shoots concentrations. The concentrations averaged 173 ppm in shoots and 1110 ppm in roots. Total and plant available soil Pb concentrations decreased in the majority of the garden sites, with a lower reduction in soil Pb on sites with higher soil pH and greater amounts of organic carbon. In general, these experiments show the potential for the use of phytoextraction as an effective cost saving alternative for removal of heavily contaminated soils.

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