PUBLIC HEALTH ASSESSMENT
ARNOLD ENGINEERING DEVELOPMENT CENTER
(a/k/a ARNOLD AIR FORCE BASE)
ARNOLD AIR FORCE BASE STATION, COFFEE COUNTY, TENNESSEE
The Agency for Toxic Substances and Disease Registry (ATSDR) prepared this public health assessment to evaluate exposure pathways and to respond to community concerns about past, current, and potential future exposures to environmental contaminants originating from Arnold Air Force Base (AAFB). On the basis of the available information, Although there are potential hazards, AAFB and the regulators are managing those potential hazards in a manner that is protective of the public health. (See the following Summary Table). Unexploded ordnance (UXO) and Camp Forrest physical hazards pose an indeterminate public health hazard. To date, no known hazardous incidents have occurred, but abandoned structures and UXOs could present hazards to the public entering the area unless visitors receive and accede to notice that the hazards may exist, and adequate instruction as to proper procedures if such hazards are encountered .
AAFB is an active military facility located in Coffee and Franklin Counties in south central Tennessee. AAFB covers approximately 40,000 acres, of which 30,000 are designated as a wildlife management area operated by the Tennessee Wildlife Resource Agency (TWRA). The main facility of the base, the Arnold Engineering Development Center (AEDC), occupies 3,600 acres roughly in the center of the base and is surrounded by a security fence. Woods Reservoir comprises 4,000 acres in the southern portion of the base. Coffee County Landfill, a 97-acre inactive landfill, is located in the northwest corner of the base. Most Air Force activity at AAFB takes place at AEDC, an aerospace technology testing center within the Air Force Materiel Command. AEDC conducts aerodynamic simulation tests, propulsion tests, and simulation of space environments. Testing, which began at AEDC in 1953, generates a number of hazardous wastes and by-products. Currently, management of these hazardous wastes is permitted and supervised by the state and the U.S. Environmental Protection Agency (EPA). In the past, however, some wastes were released into the environment, resulting in contamination. Volatile organic compounds (VOCs) have been detected in groundwater; VOCs, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, and metals have been detected in surface soil; and PCBs have been detected in sediments and fish. Physical hazards are also present at AAFB. An area used for housing and various operations during World War II contains abandoned remnants of structures such as chimneys, vehicle maintenance bays, and basements. There are also uncovered abandoned wells and missing utility hole covers. In addition, there are two former artillery ranges, one north of the runways and one south of the industrial area, where UXO has reportedly been found.
ATSDR reviewed available data from environmental monitoring conducted by AAFB and by the Tennessee Department of Environment and Conservation. In addition, ATSDR attended a Restoration Advisory Board meeting and spoke to AAFB and EPA staff to learn about community concerns regarding methane migration, groundwater contamination, cancer, and lupus. ATSDR does not believe that contaminants from AAFB are responsible for health problems such as cancer. Also, there is no known relationship between chemicals in the environment at AAFB and lupus. ATSDR identified and evaluated the following possible exposure pathways at AAFB to determine the level of hazard presented: methane migration to wells and into homes; consumption of contaminated catfish and turtles from Woods Reservoir; UXO and other physical hazards; consumption of contaminated groundwater; and contact with contaminated soil, surface water, and sediment.
In December 1998, a resident living near Coffee County Landfill was injured in a flash fire in his well house. AAFB investigated the incident and found that methane, a flammable gas generated by decomposing refuse, was migrating from the landfill. AAFB subsequently installed a methane collection and flaring system and began conducting regular monitoring in residences and a school near the landfill. Due to these preventive measures, methane migration from Coffee County Landfill currently poses no apparent public health hazard.
Although some contamination has been identified in fish collected at Woods Reservoir, fishing restrictions have been in place to warn the public that eating catfish could be a hazard. Signs instructing the community about these hazards have been posted at the reservoir. The most recent sampling reveals that contaminant levels are declining. If this trend continues, fish may be edible in the future.
Two former artillery ranges are located on base, one north of the runways and one south of the industrial area. (Both of these are outside of the AEDC fence.) These areas are possibly the locations of UXO. In addition, physical hazards such as remnants of structures, open utility holes, and abandoned wells are present at Camp Forrest. Currently, the TWRA map of the AAFB Wildlife Management Area contains a warning concerning physical hazards in Camp Forrest. AAFB is working with TWRA to draft new language concerning UXO to be included in the next version of this map. In addition, AAFB is having signs made to post on the roads leading into the two former impact areas, warning of possible UXO. ATSDR considers UXO and Camp Forrest physical hazards to be an indeterminate public health hazard because access is possible to areas where abandoned structures or UXO exist, and the extent to which visitors accede to warnings is uncertain. ATSDR concurs with AAFB's plans to increase notification efforts and recommends that additional efforts be made to notify all recreational users of potential hazards.
Various areas of groundwater contamination have been identified at AAFB. AAFB has sampled off-site private wells potentially affected by this contamination and filtration systems or connections to the public water supply have been provided to residences with affected wells. ATSDR reviewed sampling data and determined that past exposure by residents to contaminants in private well water do not pose a public health hazard. AAFB monitoring and mitigation measures should prevent current and future health hazards.
Soil, surface water, and sediment contamination at AAFB poses no apparent public health hazard. Most of the contamination is within the AEDC fenced security area, thus, the public and most AAFB personnel do not come into contact with it. Any sporadic exposure to contamination by on-site workers or in areas outside the fenced area does not pose a public health hazard.
|Exposure Scenario||Time Frame||Exposure
|Hazard (defined in Appendix C)||Actions Taken/ Recommended|
|Methane gas migrating to private wells and homes from Coffee County Landfill.||past
|past - hazard
current & future-No (apparent) hazard
|•Methane extraction and flaring to destroy methane now
in place at landfill.
•Private wells were closed in the vicinity.
•Extensive indoor monitoring now in place;levels are low.
|Consumption of catfish and turtles caught in Woods Reservoir.||past
|past - indeterminate hazard
current/future- No (apparent) hazard
|•Advisory against eating fish caught from Woods Reservoir.
•Air Force mitigating PCB sources at AAFB.
•Fish contaminant monitoring is ongoing/levels dropping.
|Unexploded ordnance and other physical hazards at Camp Forrest and two former artillery ranges north of runways and south of industrial area.||past
|past - no hazard
current/future -indeterminate hazard
|•There have been no accidents or
incidents involving UXO
•Public education and institutional control improvements are being developed to reduce risks.
|Consumption of contaminated groundwater through private wells near Coffee County Landfill, Camp Forrest, and north and northwest at AAFB.||past
|yes, some areas
past - no (apparent) hazard
current and future (down gradient of Model Shop) - indeterminate hazard
|•Alternative water was provided to people.
•Levels were not high enough to pose a hazard.
•Groundwater monitoring is underway. Sampling is planned for un-assessed areas near the Model Shop.
•Groundwater pump and treatment has been conducted at several of the sites.
|Contact with contaminated soils in various areas on AAFB.||past/ current/ future||unlikely||past/current/future- no (apparent) hazard||•Institutional controls on access to areas of concern.
•Remediation activities underway to reduce future hazards.
|Contact with surface water/sediment in Spring Creek and other surface waters.||past/ current/ future||unlikely||past/current/future- no (apparent) hazard||•Levels are not high enough to pose a health hazard.
•Mitigation of PCB sources complete, reducing future hazards.
Arnold Air Force Base (AAFB) is an active military facility located in Coffee and Franklin Counties in south central Tennessee (see Figure 1) (AAFB, 1998). AAFB covers approximately 40,000 acres, of which 30,000 are designated as a wildlife management area operated by the Tennessee Wildlife Resource Agency (TWRA). The main facility of the base, the Arnold Engineering Development Center (AEDC), occupies 3,600 acres roughly in the center of the base and is surrounded by a security fence (AAFB, 1999c; CH2MHill, 1995). The base airfield is located on the western side of AEDC, within the fenced area. Woods Reservoir, created by damming the Elk River to provide cooling water for AEDC facilities, comprises 4,000 acres. The Tennessee Air National Guard Training Area, including an active rifle range, is west of the AEDC fenced area. The base extends from Woods Reservoir and the Elk River on the south to the city of Manchester on the north. The base is bounded on the west by State Route 55, the city of Tullahoma, and alternate U.S. Route 41, and on the east by Interstate 24 (CH2MHill, 1995; AAFB, 1998; Munda, 1999a).
AAFB was established in 1951 on land formerly occupied by the Camp Forrest U.S. Army Training Center. Camp Forrest, which was active between 1941 and 1946, was used as an Army training base during World War II (AAFB, 1998; CH2MHill, 1995). Remnants of Camp Forrest structures are located in the western portion of AAFB.
Most Air Force activity at AAFB takes place at AEDC (CH2MHill, 1995). AEDC, also established in 1951, is an aerospace technology testing center within the Air Force Materiel Command (AAFB, 1999a; CH2MHill, 1995). It is owned and managed by the Air Force, with a contractor work force (AEDC, undated). AEDC conducts aerodynamic simulation tests, propulsion tests, and simulation of space environments (CH2MHill, 1995). Testing, which began at AEDC in 1953, generates a number of hazardous wastes and by-products (AAFB, 1998). Currently, management of these hazardous wastes is permitted and supervised by the state and the U.S. Environmental Protection Agency (EPA), under programs such as Title V of the Clean Air Act, the National Pollutant Discharge Elimination System (NPDES), and the Resource Conservation and Recovery Act (RCRA) (Brandon, 1999). In the past, however, some wastes were released into the environment, resulting in contamination (CH2MHill, 1995).
Contaminants that have been detected at AAFB include: chlorinated solvents and explosives in groundwater; volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and metals in surface soil; and PCBs in sediments and fish (CH2MHill, 1995).
Physical hazards are also present at AAFB. The Camp Forrest area contains remnants of structures such as chimneys, vehicle maintenance bays, and basements. There are also abandoned wells and missing utility hole covers (ATSDR, 1996; Flatt, 1999). In addition, there are two former artillery ranges, one north of the runways and one south of the AEDC industrial area, where unexploded ordnance (UXO) (undetonated, buried munitions) have been found (King, 1999a).
United States Air Force Installation Restoration Program (IRP) activity began at AAFB in the early 1980s with a Phase I Records Search that identified 17 IRP sites. Subsequent Phase II studies and other environmental assessments identified seven additional sites, bringing the total number of IRP sites to 24 (see Figure 2) (AAFB, 1998). In June 1989, EPA Region 4 conducted a RCRA Facility Assessment at AAFB, which identified 97 Solid Waste Management Units (SWMUs) and 13 areas of concern within the 24 IRP sites (AAFB, 1998; CH2MHill, 1995).
AAFB has conducted numerous sampling investigations and remedial efforts at the IRP sites; further details are provided in the section "Environmental Contamination and Evaluation of Potential Exposure Pathways" and in Table 1.
The Agency for Toxic Substances and Disease Registry (ATSDR) conducted an initial site visit at AAFB on April 10-13, 1995, during which ATSDR met with Air Force personnel and representatives from local and state agencies. Based on available data and information, ATSDR identified one completed exposure pathway (consumption of fish from Woods Reservoir), one potential exposure pathway (ingestion of drinking water from private wells near Coffee County Landfill), and one area with physical hazards (Camp Forrest). ATSDR developed educational materials to encourage people to follow the fish advisory for Woods Reservoir issued by the Tennessee Department of Health; a draft version of these materials was presented to the AAFB Restoration Advisory Board (RAB) in January 1996. ATSDR's Division of Health Education presented the materials to physicians and health professionals in the area in May 1996. ATSDR also recommended sampling of turtles from Woods Reservoir, groundwater monitoring, methane gas monitoring, and dissemination of information on potential physical hazards at Camp Forrest (ATSDR, 1996).
ATSDR conducted a second site visit on February 22-25, 1999, during which ATSDR met with Air Force and contractor personnel and representatives from EPA and the Tennessee Department of Environment and Conservation (TDEC). ATSDR also made a presentation at a RAB meeting, discussing public health issues with community members present.
To characterize the local population and to identify the presence of sensitive subpopulations, such as young children, ATSDR examine the demographics of the base and nearby communities. The current total work force at AEDC is approximately 3,250 people. Of these, about 300 are Air Force and Navy military personnel or Department of Defense civilians; the remainder are contractor employees (AAFB, 1999c). Approximately 150 people reside in 40 on-base housing units for military personnel, located in the southern part of the base near Woods Reservoir (AEDC, undated; SAIC, 1992). The neighboring towns of Manchester and Tullahoma have populations of 7,709 and 15,758, respectively. In Manchester, 13% of the population is under the age of 10 and 17% is over 65. In Tullahoma, 15% is under the age of 10 and 15% is over 65. Ninety-five percent of the population of Manchester is white, 3% is black, and 2% is of another race; Tullahoma is 92% white, 7% black, and 1% of other races (Census of Population and Housing, 1990).
Land uses in the vicinity of AAFB include farming, ranching, dairy operations, parks, forests, and reservoirs (AAFB, 1998). The primary land use immediately surrounding AAFB is rural-residential (CH2MHill, 1995). Central High School is located adjacent to AAFB to the north.
Except for the AEDC fenced area and some of the Tennessee Air National Guard area, AAFB is open to the public for recreation; it is used for hunting, fishing, biking, hiking, and horseback riding (ATSDR, 1996; King, 1999a). Access to the AEDC fenced area is controlled, with guards posted at the entrance. Most of the IRP sites at AAFB are within the AEDC fenced area. Potential for contact with physical hazards and possibly contact with UXO, are the principal concerns in areas the public is likely to access. Woods Reservoir, the principal source for water for AAFB, is accessible to the public and has been used extensively for a variety of recreational purposes. Groundwater in the area is an important source of water for domestic use.
The uppermost layers of subsurface geology in the vicinity of AAFB are as follows: at the top is the "regolith," rubble created from weathering of the bedrock; and under this is limestone (the Fort Payne Formation), underlain by a layer of shale (the Chattanooga Shale Formation). The limestone bedrock has numerous irregular fractures and solution openings. Three aquifers are present in these uppermost geological units. The shallow aquifer is found in the upper portion of the regolith, mostly a sand/silt/clay/gravel mixture. It occurs under unconfined to semi-confined conditions and averages about 30 feet in thickness. The intermediate aquifer consists of two distinct lithologic zones; the upper zone is the base of the regolith, made up of silt/sand/clay grading to rubble at the bottom, while the lower zone is the fractured limestone (top 10 to 20 feet) of the Fort Payne Formation. This aquifer ranges from 30 to 90 feet thick and occurs under semi-confined conditions. The deep aquifer occurs in the less permeable fractured limestone zone of the Fort Payne Formation. It ranges from 10 to 140 feet thick and occurs under semi-confined conditions. The Chattanooga Shale Formation underlies the Fort Payne Formation and serves as an aquitard, hindering the flow of groundwater (CH2MHill, 1995).
A major groundwater divide occurs across AAFB in a northeast-southwest direction, generally coinciding with the surface water divide (see below). Groundwater at the base generally flows away from this divide and toward the major drainages in a dispersive pattern. Groundwater withdrawals by AEDC at the J-4 test cell also influence groundwater flow. The J-4 test cell is the largest high-altitude rocket test cell in the world (AEDC, 1998). The test cell is a vertical shaft approximately 250 feet deep that is dewatered by a pumping system that removes an estimated 70 to 100 gallons of groundwater per minute. This results in a localized cone of depression, or depression of the water level, in the shallow and intermediate aquifers (CH2MHill, 1995).
Paralleling the groundwater divide, a surface water divide extends from the northeastern edge of AAFB to the southwestern edge. Surface water to the north and west of the divide flows into Normandy Lake via Crumpton Creek, while water south and east of the divide flows into Woods Reservoir and the Elk River (CH2MHill, 1995; AAFB, 1998). Part of AAFB is located within a low-lying, poorly drained, densely forested area known as "The Barrens," in which there are numerous marshes and ponds (AAFB, 1998). Surface water bodies at AAFB that are used for cooling water and drainage include Woods Reservoir, the Retention Reservoir, Bradley Creek, Brumalow Creek, and Rowland Creek (AAFB, 1995) (See Figure 3).
- Woods Reservoir, a 4,000-acre lake, was constructed on the Elk River to provide approximately 100 million gallons per day of cooling water for AEDC's test facilities (ATSDR, 1996).
- The Retention Reservoir, constructed in 1953, is an unlined impoundment of approximately 175 acres, at the western edge of the AEDC testing area. It discharges to Rowland Creek. The Retention Reservoir receives discharges from many areas of the test facility and direct runoff from the J-4 testing area (AAFB, 1995).
- Bradley Creek, Brumalow Creek, and Rowland Creek all receive runoff and/or discharges from AEDC facilities. All three creeks discharge into Woods Reservoir (AAFB, 1995).
Drinking water for AAFB is primarily supplied by Woods Reservoir. This water undergoes filtration and chlorination at a water treatment plant prior to distribution. It is tested monthly for conventional parameters, annually for inorganics and nitrate, and once every 3 years for VOCs, synthetic organics, and asbestos. No contaminants have ever been detected above water quality standards set by EPA and the state. Wells at AAFB include two at the golf course (one used for irrigation and one for potable water), one used for potable water at the Tennessee Air National Guard Rifle Range, and one used infrequently for potable water at the airfield. A well was used in the past to supply base housing with potable water, but use of this well was discontinued in the early 1990s when base housing was connected to the Estill Springs public water supply (Holt, 1999; Brandon, 1999). Wells at the AEDC Main Testing Area are used for dewatering and monitoring purposes only (SAIC, 1992).
Domestic Water Supply Wells
Numerous private domestic water wells are located within 1 mile of the AAFB boundary, primarily to the north, northwest, and south. Most of the domestic water supply wells are completed in the intermediate aquifer, although some are completed in the shallow aquifer. Residents west and downgradient of Coffee County Landfill along State Route 55 were connected to a municipal water supply in 1992 as a precautionary measure due to groundwater contamination at the landfill (CH2MHill, 1995; Brandon, 1999).
Recreational Use of AAFB
Public hunting is permitted within the wildlife management area on base during hunting season. AAFB employees are also allowed to hunt within the AEDC fenced area during hunting season (CH2MHill, 1995; TWRA, 1998). Woods Reservoir is used for recreational fishing. Crappie, bass, and catfish are the species commonly caught and kept to eat despite the warning signs around the reservoir concerning possible PCBs in catfish (ATSDR, 1996). Recreational fishing is not permitted in the Retention Reservoir (AAFB, 1995).
In preparing this public health assessment, ATSDR relied on the information provided in the referenced documents. Documents prepared for the IRP program meet specific standards for adequate quality assurance and control measures for chain-of-custody procedures, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn in this document are dependent upon the availability and reliability of the referenced information. The environmental data presented in this public health assessment are from reports produced by the Air Force and its contractors and by TDEC. ATSDR did not find any data quality problems during our examination of these data.