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Modeling Lead Binding to Metal Oxide and Organic Compounds of Particulate Material in Natural and Engineered Aquatic EnvironmentsEPA Grant Number: U914759
Title: Modeling Lead Binding to Metal Oxide and Organic Compounds of Particulate Material in Natural and Engineered Aquatic Environments
Investigators: Nelson, Yarrow M.
Institution: Cornell University
EPA Project Officer: Broadway, Virginia
Project Period: January 1, 1995 through January 1, 1996
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Engineering
The objective of this research project is to examine the role of surface coating composition in controlling trace metal adsorption in aquatic environments.
Pb adsorption was investigated using natural biofilms that developed on glass surfaces in three New York lakes and a water supply well. Adsorption isotherms were obtained for Pb binding to the biofilms in solutions with defined Pb speciation at 25°C and pH 6.0, with Pb2+ concentrations ranging from 0.1 to 2.0 µM. Adsorption isotherms for Pb binding to representative individual components of the biofilms also were determined under the same conditions. These isotherms, combined with characterization of the natural biofilm composition, were used to estimate the relative contributions of the organic and metal oxide surface coating constituents. Laboratory analogs for the organic phase of the biofilms were cells of a diatom (Navicula peliculosa) and a green alga (Chlorella vulgaris) and extracellular polymer of the bacterium Burkholdaria cepacia. The laboratory surrogates used for biofilm minerals were oxides of Fe, Mn, and Al. Pb binding to Fe oxides in the natural biofilms was estimated to be an order of magnitude greater than Pb binding of the organic phase or the Mn and Al oxides. The sum total of predicted Pb binding to Fe, Mn, and Al oxides and the organic phase accounted for 80 to 90 percent of the total observed Pb binding in the oligotrophic biofilms, and 40 to 60 percent of that observed for biofilms from the more productive lakes.