Trichloroethene (TCE) plumes extend north-northeast toward the Ohio River from the Paducah Gaseous Diffusion Plant (PGDP), a Superfund site in the Gulf Coastal Plain of western Kentucky. Wetlands in the floodplain are in the paths of these plumes, and on-site contamination has migrated downward from the Regional Gravel Aquifer (RGA) into the upper McNairy Formation, which overlies a bedrock aquifer. Intrinsic biodegradation in these two environments at the margins of the RGA could limit further contaminant migration and ecosystem or water-quality degradation. To assess cometabolic biodegradation potential in these uncontaminated environments, we attempted to culture and enumerate methanogens, sulfate- and Fe(III)-reducers, and methanotrophs, which have been implicated elsewhere as TCE degraders. Soil samples were collected at three wetland sites in the floodplain. McNairy sediments were collected beneath one of the suspected source areas at PGDP. Methanogens, sulfate reducers, and methanotrophs were abundant in wetland soils, with populations generally decreasing with depth. Methanogens were the only group cultured from McNairy sediments, and they showed little activity compared with wetland methanogen cultures. TCE loss in methanogenic batch cultures by chemoautotrophic and acetoclastic methanogens was monitored, but no significant degradation was observed.
|Number of pages||24|
|State||Published - 2001|
Bibliographical noteFunding Information:
The investigation reported in this article (No. 00-06-58) is part of a project of the Kentucky Agricultural Experiment Station and is published with approval of the Director. This work was supported by U.S. Geological Survey grant 1434-HQ-96-GR-02672 and by the Agreement-in-Principle between DOE and the Commonwealth of Kentucky through the Kentucky Water Resources Research Institute. The contents of this article do not necessarily reflect the views and policies of the U.S. Departments of the Interior and Energy, or does mention of tradenames or commercial products constitute endorsement by the United States Government. We thank DOE, the Tennessee Valley Authority, the Kentucky Department of Fish and Wildlife Resources, the Kentucky State Nature Preserves Commission, and the Mathis family for access to their properties. We appreciate the assistance of the ISGS (especially Jack Masters) and Todd Mullins with sampling and of Abigail Villalba, Karl Dawson, Jim Crutchfield, and Christofer Sweat in the laboratory.
ASJC Scopus subject areas
- Environmental Science (all)