State Water Resources Research Institute Program

Project ID: 2008DC94B
Title: Assessing the Distribution of Synthetic Organics and the degradation of Polyaromatic Hydrocarbons in the Anacostia River through Microbial and Stable Isotope Studies
Project Type: Research
Start Date: 3/01/2008
End Date: 2/28/2009
Congressional District: District of Columbia
Focus Categories: Ecology, Sediments, Toxic Substances
Keywords: Sythetic organics, polyaromatic hydrocarbons, alkanes, sediment biogeochemistry,microbial degradation, stable isotopes
Principal Investigators: Bushaw-Newton, Karen L.; MacAvoy, Stephen E.
Federal Funds: $ 15,000
Non-Federal Matching Funds: $ 29,336
Abstract: Synthetic organics are a serious form of pollution affecting the biological life of the Anacostia River. Polycyclic Aromatic Hydrocarbons (PAHs), a by-product of engine combustion, are distributed throughout the sediments of the river system and have been linked to cancer in higher organisms including catfish. Various alkanes such as chlordane, a pesticide banned by the EPA in 1988 and contaminants such as methyl isobutyl ketone (MIBK), a commonly used solvent, have also been found in the sediment though their distribution is not well-documented. While the presence of PAHs in the sediment is well studied, it is not known if these compounds are being actively degraded or modified by the microbial community within the sediments. Bacteria are known degraders of PAHs and other organic compounds due to their diverse metabolic capabilities. In order to assess the potential for the health of the river to improve it is important to have a better understanding of the bioremediation activities occurring within the river system as well as a better understanding of the distribution and persistence of less-studied alkane contaminants. The objectives of this research are 1) to determine the presence and activity levels of bacteria capable of degrading PAHs in the Anacostia River system, and 2) to assess the distribution and abundance of important (potentially toxic) synthetic organic compounds. This work will involve 1) characterizing and isolating the bacterial communities and individual bacteria capable of degrading PAHs and 2) assessing the distribution and types of alkanes at sites throughout the river system. Sites will be chosen from upstream branches through downstream locations and the sediment will be sampled for microbial and chemical characteristics. Genetic probes will be used to identify specific genes involved in organic contaminant degradation while metabolic probes will examine the ability of total microbial communities as well as isolated microbes to breakdown different carbon compounds including PAH compounds. Using bacterial isolates and stable isotopes the flow of carbon through the river will be traced. Chemical analyses of the bulk sediment will include analyses for alkanes and the stable isotopes of carbon, nitrogen, and sulfur. Through our research, we will be able to provide knowledge of bioremediation activities and in turn will potentially provide information on areas of active bacterial degradation. Second, our studies will enhance the knowledge on distributions and locations of other organic contaminants, such as alkanes. Third, by having students as an important component of our Anacostia River research, we are not only advancing the future of science but also enhancing the importance of taking care of your local watershed.

Progress/Completion Report, PDF

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