Q-190. A Characterization of the Polyaromatic Hydrocarbon Microbes Present in Sediment of a Northeastern US River Impacted by Historical Manufactured Gas Plant Operations

A. Consiglio, L. Houghton-Robinson, A. Hollar, D. Napsey, C. Johnson, C. Magnuson, D. Junge, L. A. Launen;
Keene State Coll., Keene, NH.

Legacy contamination due to the historical operation of former manufactured gas plants (MGPs) has led to the contamination of sediments at thousands of locations in the United States. Some of the major constituents of MGP waste are polyaromatic hydrocarbons (PAHs) which are listed as priority pollutants. In sediments, PAH removal is largely achieved through microbial degradation, yet an understanding of the microbes that degrade PAHs in sediments, and of how site conditions can influence these microbial processes, is limited. Accordingly, the aim of this research is to characterize the PAH-degrading microbes present in MGP-contaminated freshwater sediment using a combination of pure culture and microcosm approaches. Sediments from a river in the northeastern United States that are proximal to a former MGP have been identified as highly PAH-contaminated, containing total PAH concentrations ranging from 17.5 mg/Kg to 4360 mg/Kg. Using samples collected from the top 10 cm layer of this sediment we have isolated several aerobic PAH-degrading bacteria using enrichment culture techniques. Microcosm studies designed to assess the influence of oxygen availability and nutrient supplementation (nitrogen and phosphorus) on PAH degradation by the intact sediment microbial communities have been conducted. The information gained from this research is applicable to the use of microbial degradation to support the removal of PAH contamination from sediments impacted by former MGP operations.