Biotic and Abiotic Reductive Transformation of Chlorinated Solvents in Iron-Reducing SedimentsEPA Grant Number: U915327
Title: Biotic and Abiotic Reductive Transformation of Chlorinated Solvents in Iron-Reducing Sediments
Investigators: McCormick, Michael S.
Institution: University of Michigan
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1998 through September 1, 2001
Project Amount: $91,044
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Fellowship - Environmental Engineering , Engineering and Environmental Chemistry , Academic Fellowships
The objectives of this research project are to: (1) investigate the reductive transformation of chlorinated solvents in iron-reducing sediments; and (2) assess the relative contributions of biological and abiotic reactions to dechlorination.
Microcosm studies will be employed to screen for dechlorination activity in pure cultures and enrichments of iron-reducing bacteria with a variety of chlorinated compounds, including: hexachloroethane, tetrachloroethylene, 1,1,1-trichloroethane, and carbon tetrachloride. Selective metabolic inhibitors will be used in enrichment cultures to control for sulfate-reducing and methanogenic populations. Strictly biological rates of dechlorination will be determined in whole-cell suspensions of the bacterial cultures. Abiotic reaction rates will be studied in microcosms containing biologically reduced mineral species (e.g., biogenic magnetite Fe3O4), which have been washed to remove cells. The reactivity of synthetic forms of the same reduced mineral species also will be examined for comparison. Finally, in defined systems containing both cells and iron oxide solids, the effects of temperature on dechlorination kinetics will be used to distinguish biologically mediated reactions (usually inhibited at temperatures greater than 60°C) from abiotic reactions.