Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. Numerous site-specific ground-water contamination investigations have been conducted at designated solid waste management units (SWMUs) at AAFB. Several synthetic volatile organic compounds (VOCs), primarily chlorinated solvents, have been identified in groundwater samples collected from monitoring wells near SWMU 8 in the Spring Creek area.
During April and May 2000, a study of the groundwater resources in the Spring Creek area was conducted to determine if VOCs from AAFB have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. The study focused on sampling private wells located within the Spring Creek area that are used as a source of drinking water. Ground-water-flow directions were determined by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 35 private wells and 22 monitoring wells during the period of study. Depths to ground water were determined for 22 of the private wells and all 22 of the monitoring wells. The wells ranged in depth from 21 to 105 feet. Water-level altitudes ranged from 930 to 1,062 feet above sea level. Depths to water ranged from 8 to 83 feet below land surface. Water-quality samples were collected from 29 private wells which draw water from either gravel zones in the upper part of the Manchester aquifer, fractured bedrock in the lower part of the Manchester aquifer, or a combination of these two zones.
Concentrations of 50 of the 55 VOCs analyzed for were less than method detection limits. Chloroform, acetone, chloromethane, 2-butanone, and tetrachloroethylene were detected in concentrations exceeding the method detection limits. Only chloroform and acetone were detected in concentrations equal to or exceeding reporting limits. Chloroform was detected in a sample from one well at a concentration of 1.2 micrograms per liter (µg/L). Acetone was detected in a sample from another well at a concentration of 10 µg/L. Acetone also was detected in a duplicate sample from the same well at an estimated concentration of 7.2 µg/L, which is less than the reporting limit for acetone. The only contaminant of concern detected was tetrachloroethylene. Tetrachloroethylene was detected in only one sample, and this detection was at an estimated concentration below the reporting limit. None of the VOC concentrations exceeded drinking water maximum contaminant levels for public water systems.
Executive summary
Introduction
Purpose and scope
Study area
Hydrogeologic setting
Groundwater levels
Groundwater quality
Physical properties
Volatile organic compounds
Quality-assurance/quality-control samples
Summary
References
APPENDIX 1. Physical properties of water from private wells sampled in the Spring Creek area near Arnold Air Force Base, Tennessee
APPENDIX 2. Volatile organic compounds detected in water from private wells sampled in the Spring Creek area near Arnold Air Force Base, Tennessee
APPENDIX 3. Trip-blank and equipment-blank data for volatile organic compounds detected in water from private wells sampled in the Spring Creek area near Arnold Air Force Base, Tennessee
For addtional information contact:
District Chief
U.S. Geological Survey
640 Grassmere Park, Suite 100
Nashville, Tennessee 37211
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Box 25286, Federal Center
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