350-2 Macroscopic and Molecular-Scale Assessment of Soil Lead Contamination Impacted by Seasonal Dove Hunting Activities.



Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

Yuji Arai, Dept of Entomology Soils Plant Sciences, Clemson University, Clemson, SC, Allison Rick, Clemson University, Clemson, SC, Tessa Saylor, Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC, Emily Faas, Department of Biosystems Engineering, Clemson University, Clemson University, Clemson, SC, Ryan tappero, National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY and Antonio lanzirotti, Department of Geophysical Sciences, University of Chicago, Chicago, IL
Environmental contamination of lead (Pb) in soils and sediments poses serious threats to human and ecological health. The objective of this study is to investigate the effect of seasonal dove sports hunting activities on Pb contamination in acid forest soils. A grid sampling method was used to investigate the spatial distribution of Pb contamination in surface soils. Soils were analyzed for total metal(loid) concentration and characterized for physicochemical properties and mineralogy. Adsorption isotherm experiments were also conducted to understand the reactivity and retention capacity of Pb(II) in soils. Finally, synchrotron based X-ray microprobe and X-ray absorption spectroscopy were used to understand the chemical speciation of Pb that controls the retention/release mechanisms of Pb in soils. There was no excessive accumulation of Pb at the site. However, the concentration of Pb in surface soils was greater than the background level (<16 mg kg-1). The contamination level of Pb was as high as 67 mg kg-1 near a patch of corn field where lime was frequently applied. Microfocused X-ray microprobe analysis showed the presence of Pb pellet fragments that predominantly contain oxidized Pb(II), suggesting that oxidative dissolution was occurring in soils. Dissolved Pb(II) can be readily retained in soils up to ~3,600 mg kg-1 via inner-sphere and outer-sphere surface complexation on carbon and aluminol functional groups of soil components, suggesting that partitioning reactions control the concentration of Pb in soil solution. The fate of Pb is likely to be controlled by 1) oxidative dissolution process of Pb(0) pellets and 2) the release of outer-sphere and/or inner-sphere Pb surface complexes in humic substances and aluminosilicate/Al oxyhydroxides. Although no remedial actions are immediately required, the long-term accumulation of Pb in soils should be carefully monitored in protecting ecosystem and water quality at the dove hunting field.
See more from this Division: S02 Soil Chemistry
See more from this Session: Metals and Metaloids: II