USGS

Biodegradation of Chlorinated Ethenes at a Karst Site in Middle Tennessee

FIGURES

1-3. Diagrams showing:

1. Common biological degradation processes for chlorinated ethenes

2. Oxidation-reduction potentials for selected microbial processes

3. Examples of cometabolic processes that degrade chlorinated ethenes

4-7. Maps showing:

4. Location of ground-water monitoring and remediation activities at the study site in Marshall County, Tennessee

5. Typical potentiometric surface conditions for the shallow water-bearing zone

6. Bedrock surface at the study site

7. Spatial distribution of chlorinated ethenes in the shallow water-bearing zone

8. Diagram showing the generalized hydrogeology of the Middle Tennessee study site

9. Map showing the effect of pump-and-treat wells on water levels in deep wells

10. Radial diagrams used to illustrate electron acceptor processes

11. Map showing geochemical conditions of water samples collected from selected shallow wells, August 21, 1997

12. Bar graph showing chlorinated-ethene data for water samples collected from well 33S

13. Map showing nitrate and ammonia concentrations in samples from selected shallow wells

14-15. Bar graphs showing:

14. Geochemical data for water samples from well 7S

15. Daily rainfall totals for a 1-month period before each ground-water sampling event

16. Radial diagram showing typical geochemical conditions for anaerobic water samples collected from deep wells

17-27. Graphs showing:

17. Concentrations of chlorinated ethenes in water samples collected from selected deep wells on November 4 and 5, 1997

18. Temporal changes in chlorinated-ethene concentrations in water samples from wells 3D and 4D

19. Continuous ground-water monitoring data collected from well 12D for water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 13 through May 19, 1998

20. Continuous ground-water monitoring data collected from well 12D showing rapid changes in water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 31 through April 1, 1998

21. Chlorinated-ethene concentrations in water samples collected from well 12D

22. Trichloroethylene concentrations during microcosm experiment 2

23. Relative amounts of trichloroethylene and reductive-dechlorination degradation products in experiment 1 microcosms after 10 months of incubation

24. Continuous ground-water monitoring data collected from well 1D for water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 18 through May 20, 1998

25. Continuous ground-water monitoring data collected from well 3D for water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 19 through May 20, 1998

26. Continuous ground-water monitoring data collected from well 2D for water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 31 through April 5, 1998

27. Continuous ground-water monitoring data collected from well 2D for water level, specific conductance, dissolved oxygen, and oxidation-reduction potential, March 13 through May 20, 1998

28-30. Diagrams showing:

28. Lines of evidence needed to evaluate biodegradation of chlorinated solvents in the shallow water-bearing zone

29. Lines of evidence needed to evaluate biodegradation of chlorinated ethenes in the karst aquifer

30. Hydrogeology determines residence time of ground water, which influences the biological community, the geochemistry, and the biodegradation of chlorinated ethenes in karst aquifers


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