Pb Speciation, Groundwater Mobility and Bioavailability Through A Forested Ecosystem

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9807679MorrisThis proposal uses lead smelting in the oak-hickory forests of SE Missouri as a natural laboratory for studying the groundwater mobility, speciation and bioavailability of Pb, Cd, Cu and Zn. The P.I.s' preliminary work shows that the isotope composition of lead washed from leaf surfaces maps the fallout of particulate lead around the smelter. Residual lead from inside plant leaves represents Pb from the soil; initial isotope data and high Pb concentrations inside the leaves strongly suggest that smelter Pb is groundwater soluble, mobile and bioavailable. Thus, the widely recognized ecosystem and human health hazards of particulate Pb may set the stage for more subtle, but more widespread, effects due to mobilization of anthropogenic Pb in groundwater and its biomagnification. The P.I.s propose to address the redistribution and bioavailability of Pb through studies of atmospheric deposition, an ecosystem audit, studies of biological isotope fractionation, and theoretical models of speciation and transport. Undergraduate classes in the Departments of Earth and Planetary Sciences, Chemical Engineering and Biology will participate in field, analytical and theoretical work. High school students will be involved in all phases, through the NSF Young Scholar's Program.This proposal was part of the Environmental Geochemistry and Biogeochemistry program. It will be jointly funded by the Division of Atmospheric Sciences, Division of Chemistry, Division of Earth Sciences, and by the MPS Office of Multidisciplinary Activities.