Spectral Characterization of Humic SubstancesEPA Grant Number: R822251
Title: Spectral Characterization of Humic Substances
Investigators: McGown, Linda B.
Institution: Duke University
EPA Project Officer: Hiscock, Michael
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $332,309
RFA: Exploratory Research - Chemistry and Physics of Water (1995) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Engineering and Environmental Chemistry
Description:The goal of this project is to provide new, fundamental information about humic substances and their binding interactions with organic compounds and metals that will increase our ability to evaluate and predict their role in environmental processes. Investigations will use molecular probe techniques based on absorption and fluorescence spectroscopies and fluorescence lifetime techniques. Studies will examine both intrinsic probes that are integral to the humic substances and extrinsic probes that are added to the samples to report on structure, conformation and binding interactions of the humic substances. Specific goals include the following: (1) identification of photophysical properties of humic substances that are good for classifying environmental water samples and discriminating among them, to serve as the basis for predictive modeling; (2) elucidation of binding interactions of humic substances with organic compounds and metals, including relative strength and specificity of binding, the nature and heterogeneity of the various binding microenvironments, and the effects of binding on the conformation of humic substances and on their subsequent binding interactions with other chemicals; and (3) effects of natural and synthetic surfactants on the conformation and aggregation of humic substances and their binding interactions with other chemicals.
Initial focus is on isolated humic substances from commercial vendors and "standard" humics from the International Humic Substance Society (IHSS). Later studies will tackle the even more complex case of real water samples. All environmental water samples are of interest, including ground water, fresh surface waters and sea water.