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Reductive Dechlorination and Degradation of Model Chlorophenols in Marine and Estuarine SedimentsEPA Grant Number: GF9501732
Title: Reductive Dechlorination and Degradation of Model Chlorophenols in Marine and Estuarine Sediments
Investigators: Warner, Kimberly A.
Institution: University of Maryland
EPA Project Officer: Broadway, Virginia
Project Period: June 1, 1995 through January 1, 2000
Project Amount: $23,150
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology
The two primary objectives of this research project are 1) to examine the potential for microbial degradation and the effect of increasing periods of anoxia on the subsequent aerobic degradation of model chlorinated aromatic hydrocarbons (CAHs) in laboratory studies with surficial sediments from two sites in the Chesapeake Bay, and 2) to examine and define environmental factors relevant to the onset of CAH reductive dechlorination in a well-defined estuarine sediment system through field and laboratory investigations and to determine the role of sulfate respiring bacteria (SRB) in this process.
For the first objective, surficial sediments from a contaminated and relatively clean site will be used in laboratory sediment slurry studies to examine the relative rates of CAH degradation and mineralization under air, nitrogen, or sequential nitrogen/air atmospheres. Mineralization will be followed by measuring the evolution of radiolabeled carbon dioxide formation from dosed C-labeled 2,4-DCP and polychlorinated biphenyls treatments. Reductive dechlorination of the non-labeled CAHs will be followed in strict anaerobic batch slurries incubated in parallel with the radiolabeled treatments. For the second objective, sediment cores from the upper, mid, and lower Chesapeake Bay will be collected during summer and fall cruises 2,4-DCP will be injected into sediments from distinct horizons in cores. The downcore spatial distribution of reductive dechlorination activity will be considered as a function of the distribution of relevant solutes, S-sulfate reduction rates, ambient methane and hydrogen levels, as well as in its response to the seasonal migration of redox boundaries.