PETITIONED PUBLIC HEALTH ASSESSMENT
EGLIN AIR FORCE BASE
(a/k/a EGLIN AIR FORCE BASE ARMAMENT DIVISION
EGLIN AIR FORCE BASE, OKALOOSA COUNTY, FLORIDA
Eglin Air Force Base (AFB) is in the Florida Panhandle between Pensacola and Panama City. It is the largest forested military reservation in the United States, covering approximately 464,000 acres. Most of the Eglin Reservation is undeveloped, with small pockets of developed and semi-developed areas. Since 1935 it has been the Air Force's primary munitions testing and training facility.
Munitions training and testing, other standard defense missions and related activities, and waste handling practices have contaminated some areas on Eglin. In 1981, the Department of Defense initiated the Installation Restoration Program to identify, evaluate, and clean up contamination from past military activities. Throughout the history of the program, the Air Force has completed site investigations, interim measures, and removal/remedial actions at Eglin AFB, resulting in a "no further action"(1) status for many of these sites.
In February 1998, the Agency for Toxic Substances and Disease Registry (ATSDR) was petitioned to assess Eglin AFB for potential public health hazards. On April 6-8, 1998, and again on August 20-23, 2001, ATSDR visited Eglin AFB to evaluate the petitioner's concerns as well as other concerns identified during the public health evaluation process.
From talking with the petitioner and other community members, ATSDR identified five main issues of concern that are addressed in this public health assessment. To determine whether people are being exposed to levels of contamination that might cause health problems, ATSDR considers how people might come into contact with a chemical, what levels people might encounter, and for how long. If the environmental data show that people have or could come into contact with harmful chemicals at the site, ATSDR reviews the existing scientific information to determine if exposures are expected to result in harmful health effects. Based on a thorough review of the available information, data, modeling analyses, and calculated assumptions, ATSDR reached the following conclusions:
ATSDR reviewed information characterizing the magnitude and duration of relevant chemical releases from Eglin AFB, including those from herbicide spraying, OB/OD activities, prescribed burns, wildfires, and a past structural fire (C-6 Radar Facility). ATSDR determined that previous herbicide and pesticide spraying activities, current OB/OD operations, and a past structural fire do not pose a public health hazard. Contaminant levels in off-base residential areas would have been lower than levels expected to cause harmful health effects.
A prescribed burn is an intentional controlled fire. A wildfire is a fire caused by an accidental act of nature or man. To address whether on-base prescribed burns or wildfires pose a health hazard to off-base residents, ATSDR considered two different aspects of on-base fires. First, ATSDR evaluated whether fires in areas where soil contamination exist could cause contaminants to become airborne and transported to off-base residential areas. Then, exposure to chemicals released during the burning of plant material (trees, grasses, shrubs, etc.) was considered. Uncontrolled wildfires present much greater threat because their uncontrolled nature can cause them to burn longer and much greater area thus producing more hazardous substances into the air.
The findings indicate that the contaminants in soils (depleted uranium and herbicides, including Herbicide Orange(2)) would not reach off-base areas at levels associated with harmful health effects. Therefore, off-base residents would not come in contact with those contaminants.
However, the burning of plant material causes a release of particles and natural combustion products (smoke) that could cause some short-term adverse health effects (e.g., burning, itching or watery eyes; nausea; breathing difficulty; and asthma-like symptoms) in those people exposed. The frequency of such burns is low and the duration is very short (personal communication with Eglin AFB personnel, July 2002). Airborne emissions from prescribed burns and wildfires have not been measured. This evaluation is based on health effects seen from other wildfires. Individuals highly sensitive to the effects would be anyone with previous respiratory conditions such as asthma or emphysema, children, and the elderly. Health effects would likely be of short duration, i.e., developing within a few days of exposure and lasting no more than two or three weeks after exposure stopped.
Depleted uranium would not be an airborne contaminant from the burning of plant material since plants have a minimal uptake of uranium from soil.
During prescribed burns, Eglin takes several measures to minimize the impacts of fires on residential neighborhoods. ATSDR recommends that Eglin AFB continue notifying the entire community (especially potentially impacted communities) when the prescribed burns are scheduled. This allows people to take measures to reduce potential exposures. If people are experiencing respiratory problems, they should seek the attention of their personal medical care provider.
No. Based on ATSDR's review of available data, Air Force documents, and scientific literature, the chemicals detected in the surface water bodies, sediments, and fish are below levels of health concern. Contact with the water or eating fish from those water bodies presents no public health hazard.
Information on the unnamed pond near the North Gate could not confirm whether it might have contained Herbicide Orange. The presence of a sign in the pond indicating Herbicide Orange use is unsupported by the Air Force historical documents and herbicide testing information. Nevertheless, access to this area is limited and any potential exposure would be minimal.
No. The C-6 Radar Facility is located approximately 3 miles north of the town of Portland. The site is in an undeveloped section of Eglin AFB that is closed to the public. During a 2000 site investigation, the extent of the trichloroethylene (TCE) contamination was defined to be entirely on Eglin AFB property. To ensure that the contamination does not migrate to areas where people are using groundwater wells, long-term monitoring of the groundwater is conducted at the site on an annual basis. Therefore, this site poses no past, present, or future public health hazard.
No. Human exposure to herbicide contamination on Eglin AFB is minimal. Access to the Herbicide Exposure Unit (DP-09 and SS-25), the C-52A Aerial Overspray Area (AOC-24), and Hardstand 7 (SS-26) has been, is, and will continue to be restricted by locked gates, fences, security personnel, and topography. Even though people have access to Upper Memorial Lake (LF-51), the herbicide contamination was detected in the subsurface soil, and contact with subsurface soil would be minimal since Eglin AFB has implemented land use controls to minimize exposure. In addition, remedial activities have removed or contained, or both, the contamination formerly present at Mullet Creek Drum Disposal Site (DP-09) and Hardstand 7. Therefore, because contact with contamination is minimal, these sites pose no past, present, or future public health hazard.
No. Access to the Isotope Burial Area (AOC-63/AOC-67), Test Area C-64 (RW-40), and Test Area C-74L (RW-41) is restricted by locked gates, fences, and security guards. Furthermore, because of the nature (chemical and physical forms) of the depleted uranium and other radioactive contamination, ATSDR does not expect that anyone would be exposed to radioactive contamination present at these sites. In addition, remedial activities have removed or reduced the contamination that was once present. Therefore, these sites pose no public health hazard. Still, although access is restricted, the Low-level Radioactive Waste Site (RW-42) is not fenced and trespassing by boat could occur. However, the measured radiation levels were at or near normal background levels. Thus, despite the fact exposure is possible, the frequency and duration would be minimal. Accordingly, this site poses no public health hazard.
| Exposure Hazard Summary Table - Eglin Air Force Base, FL | |||
| Community and ATSDR Questions on Possible Exposures | Did Exposure Occur? | Hazard Category(3) | Comments |
| Are air releases from herbicide spraying
and open burning/open detonation (OB/OD) exposing off-base populations
to unsafe chemical levels? (Herbicide Exposure Unit, Ranges C-62/C-52N) |
In the past, present, and possibly in the future, people would be exposed. | The exposure presents no apparent public health hazard. |
• Available data for the most extensive herbicide spraying activities suggest that air concentrations did not reach unsafe levels at off-base locations. • All of the chemicals released to the air during OB/OD activities did not exceed EPA's regulatory standards. |
| Are air releases from prescribed burns and wildfires harmful to off-base populations? | In the past, present, and possibly in the future, people would be exposed. | The exposure presents a public health hazard, short-term effects. |
• Winds could occasionally blow plumes of potentially unhealthy smoke toward residential neighborhoods. If, however, harmful health effects occur, they are typically short-term, reversible, and subside after fires are extinguished. |
| Were air releases from a structural fire at C-6 Radar Facility in 1965 harmful to off-base residents? | People were possibly exposed in the past. | The exposure presents no apparent public health hazard. |
• The C-6 Radar Facility is 3 miles from Portland; therefore, contaminants that could have been in the smoke would have been significantly dispersed. The fire lasted only one day; therefore, inhalation exposures to contaminants were extremely short-lived. |
| Are chemicals from Eglin AFB seeping into Tom's Bayou and if so, would swimming, wading, or eating fish from the bayou be harmful to my family's health? | In the past, present, and possibly in the future, people would be exposed. | The exposure presents no apparent public health hazard |
• Even though contamination is present at sites on Eglin Main Base that are within the Tom's Bayou drainage basin, the levels detected are too low to be of health concern at these source areas. |
| Are people exposed to harmful contamination via swimming or fishing in Weekly Pond; Pocosin Pond; Mullet, Trout, and Basin Creeks; and a pond near the North Gate? | In the past, people were exposed. Currently and in the future, exposure is not likely. | The exposure presents no apparent public health hazard. |
• Even though pesticides were detected in the fish from Weekly Pond, the levels detected were too low to be of health concern for anyone eating the fish in the past. Currently, people are not allowed to eat fish from this pond. • People are not allowed to catch and eat fish from Pocosin Pond and no appreciable contamination exits. • Even though contamination is present in Mullet, Trout, and Basin Creeks, the levels detected are too low to be of health concern. • It is not expected that anyone could come in contact with Herbicide Orange at the unnamed pond near the North Gate often enough or in high enough doses to be a cause for health concern. |
| Is groundwater contamination from the C-6 Radar Facility reaching off-base residential wells? | No, not in the past or currently and not likely in the future would people be exposed. | No public health hazard |
• Although contamination is present in the groundwater at the C-6 Radar Facility, it is not affecting the nearest down-gradient wells. To ensure that the contamination does not migrate to areas where people are using groundwater wells and for restoration purposes, the Air Force is conducting long-term monitoring of the groundwater at the site on an annual basis. |
| Could people be exposed to harmful levels of herbicide contamination at the Herbicide Exposure Unit (SS-25/DP-09), C-52A Aerial Overspray Area (AOC-24), and Hardstand 7 (SS-26) (reported Herbicide Orange sites)? | No, not in the past or currently, and not likely in the future would people be exposed. | No public health hazard |
• Even though contamination is present at these sites, public access is restricted. |
| Could people be exposed to harmful levels of herbicide contamination at Upper Memorial Lake (LF-51), a reported Herbicide Orange site? | No, not in the past or currently, and not likely in the future would people be exposed. | The exposure presents no apparent public health hazard. |
• Even though contamination is present in the subsurface soil at this site, people who have access to the area would have minimal contact with subsurface soils, since Eglin AFB has implemented land use controls to minimize exposure. Could people be exposed to harmful levels of herbicide contamination at Upper Memorial Lake (LF-51), a reported Herbicide Orange site? |
| Could people be exposed to harmful levels of radioactive contamination from the Isotope Burial Area (AOC-63/-67), Test Area C-64 (RW-40), Test Area C-74L (RW-41)? | No, not in the past or currently, and not likely in the future would people be exposed. | No public health hazard |
• Even though contamination is present at these sites, public access is restricted and available information indicates that the contamination is localized within some of these areas. |
| Could people be exposed to harmful levels of radioactive contamination at the Low-Level Radioactive Waste Site (RW-42)? | Possibly in the past, present, and future people would be exposed. | The exposure presents no apparent public health hazard. |
• Although access is restricted, the Low-level Radioactive Waste Site is not fenced and trespassing by boat from the Gulf of Mexico or Santa Rosa Sound could occur. However, radiation levels are not at levels of health concern. |
A. Site Description and Operational History
Eglin Air Force Base (AFB) is an active military base located in Okaloosa, Walton, and Santa Rosa counties on the Florida Panhandle between Pensacola and Panama City (see Figure 1). The Eglin Reservation, as it is called, is the largest forested military reservation in the United States, covering approximately 464,000 acres (725 square miles) (EA Engineering, Science, and Technology 1997; Eglin AFB 2000c).
Eglin AFB was founded in 1935, as the headquarters for a bombing and gunnery base. In 1941, the Air Proving Ground Center was established at the base. During 1942, the Air Force began testing combat aircraft and equipment. Throughout and after World War II, Eglin AFB was the center for developing and testing new techniques and tactics in air armament. In 1968, the Air Proving Ground Center was renamed the Armament Development and Test Center, but Eglin AFB continued to research, develop, and test nonnuclear munitions. In 1989, the Armament Development and Test Center was renamed, to the Munitions Systems Division and, in 1990, to the Air Force Development Test Center. The Center tests and evaluates nonnuclear munitions, guided munitions, and electronic combat systems (Eglin AFB 2000c).
B. Remedial and Regulatory History
Standard defense missions or other related activities at Eglin AFB, such as storage, maintenance, and shipping of war material; research and development; and aircraft operations and maintenance, have contaminated some areas on Eglin AFB property. In 1981, the Department of Defense initiated the Installation Restoration Program (IRP) to identify, evaluate, and clean up contamination from past military activities. The Defense Environmental Restoration Account funds the IRP (EA Engineering, Science, and Technology 1997). As of March 2000, Eglin AFB identified 118 IRP and 17 compliance sites found to contain harmful materials (Eglin AFB 2000c). In addition, based on limited historical or circumstantial information, Eglin AFB has identified 236 areas of concern (AOCs) and 202 points of interest (POIs) which are pre-regulatory sites with the potential for contamination (Eglin AFB 2000c). Throughout the history of the IRP at Eglin AFB, the Air Force has completed numerous site investigations, interim measures, and removal/remedial actions that have resulted in a No Further Action status for many of these sites.
For detailed information on the Air Force's continued environmental investigation and remediation plans at Eglin AFB, refer to Eglin AFB's documents at the following three public repositories: the Learning Resource Center at Okaloosa-Walton Community College, Niceville Campus; Eglin Air Force Base AAC/EMR (207 N. Second Street, Bldg. 216); and at the Florida Department of Environmental Protection (FDEP), Twin Towers Office Building (2600 Blair Stone Road) in Tallahassee, Florida.
In February 1998, a private citizen petitioned (see text box for definition), the Agency for Toxic
Substances and Disease Registry (ATSDR) to assess
contamination from Eglin AFB for potential public health
hazards. ATSDR is responding to this petition in a
document known as a public health assessment. Through
the public health assessment process ATSDR examines
what chemicals enter the environment, how they move
through the environment, whether people are being exposed to these chemicals, and the levels of
chemicals that people might encounter. ATSDR uses this information to determine whether
people are exposed to levels of contamination that might cause health problems. ATSDR's
evaluation focuses on public exposure and does not address exposure of base personnel who have
access to the areas of concern.
After receiving the petition letter and speaking with the petitioner, ATSDR on April 6-8, 1998, made a site visit to Eglin AFB. ATSDR staff scientists toured the multiple sites referred to by the petitioner and met with representatives from the base, Air Force, and the United States Environmental Protection Agency (EPA). On August 20-23, 2001, ATSDR toured the site for a second time to further evaluate the sites referred to by the petitioner as well as other sites ATSDR identified during the public health assessment process.
From talking with the petitioner and other community members, ATSDR identified five potential exposure pathways. They are listed below and addressed in detail in this public health assessment:
D. Demographics, Land Use, and Natural Resource Use
ATSDR examines demographic data (i.e., population information) to determine the number of people potentially exposed to environmental chemicals and to determine the presence of sensitive populations, such as women of childbearing age (age 15-44), children (age 6 and younger), and the elderly (age 65 and older), see Figure 4. Demographic data also provide details on population mobility which, in turn, helps ATSDR evaluate how long residents might have been exposed to environmental chemicals. ATSDR also examines land and natural resource use to determine what activities might put people at risk for exposure. Some of the general information used in that analysis is provided below.
Okaloosa, Santa Rosa, and Walton Counties
Eglin AFB is located in portions of Okaloosa, Santa Rosa, and Walton counties. According to the 2000 United States (US) Census, Okaloosa County has the largest population (170,498 people), but is the smallest county in area (936 square miles); this results in the highest population density (182 people/square mile) of the three counties. Santa Rosa County is the next smallest county (1,016 square miles) with a population of 117,743 people; resulting in a population density of 116 people/square mile. Walton County has a considerably smaller population (40,601 people) and an area of 1,058 square miles; resulting in a much smaller population density (38 people/square mile) than the other two counties.
Demographics within one mile of Eglin AFB
A combination of commercial, residential, and undeveloped land surrounds Eglin AFB (EA Engineering, Science, and Technology 1997). According to the 2000 US Census, 101,792 people live within one mile of Eglin AFB–9,727 people are children aged 6 years and younger, 22,154 people are women of child-bearing age, and 11,014 people are adults aged 65 and older (see Figure 4). The total number of housing units within a one-mile buffer is 44,406.
Freeport and Portland
Freeport and Portland are small communities located within 2½ miles of the southeastern border of Eglin AFB. According to the 2000 US Census, nearly 1,100 people live in Freeport–106 people are children aged 6 and younger, 205 people are women of child-bearing age, and 159 people are adults aged 65 and older. Portland has a population of nearly 200 people–17 people are children aged 6 and younger, 31 people are women of child-bearing age, and 21 people are adults aged 65 and older.
On-Base
Most of the Eglin Reservation is undeveloped (458,400 acres) with small pockets of developed (1,400 acres) and semi-developed areas (4,200 acres), see Figure 2 (EA Engineering, Science, and Technology 1997). Eglin Main Base is the largest developed complex on the reservation (see Figure 3). It is located in the south central portion of Eglin Reservation and employs about 15,000 military and civilian workers. Hurlburt Field is about 11 miles west of the Main Base and employs about 6,000 people. Duke Field and Camp Rudder are smaller areas that employ 50 and 300 workers, respectively.
About 65% (280,000 acres) of the Eglin's 464,000 acre reservation is open to the general public for outdoor recreation (Eglin AFB 2000d). Members of the public, as well as off-duty military members, can purchase recreational permits for a variety of activities from hunting to hiking. Approximately 12,000-14,000 people apply for permits to fish, hunt, camp, hike, or bike on the reservation every year (Daily News 2000a). In addition, every permit purchaser must watch an educational video and accept a brochure on the hazards of unexploded ordnance (UXO) and the proper procedure to take should they encounter one (Eglin AFB 2000d). Areas that have been determined to contain a known potential for UXO are closed to the public. To date, Eglin reservation has no recorded incidents involving a recreational user and UXO on the reservation (personal communication with Eglin AFB personnel, July 2002). The sections of the reservation that are restricted to all forms of public access are clearly posted with "Do Not Enter" signs and are marked in red on the Outdoor Recreation, Hunting, and Fresh Water Fishing Map (Eglin AFB 2000b). Those who purchase permits receive this map with an extensive list of regulations outlining permitted recreational activities on the Eglin Reservation.
With the appropriate permits, fishing is permitted in several lakes and ponds on the Eglin Reservation, as indicated below.
|
Lakes and Ponds on Eglin Reservation |
||||
| Anderson* | Atwell | Brandt | Brown | Buck |
| Bull | College | Crain | Duck† | Indigo‡ |
| Jack§,¶ | Jr. Walton | Kepner | Lost Boy‡ | Lower Memorial§ |
| Upper Memorial§,¶ | Pocosin†† | Speck | Roberts | Timberlake |
| Weekly§,¶ | * Handicap accessible fishing
pier and nature trail † Special Creel limits apply ‡ Currently closed for renovation § Restricted to DOD-affiliated personnel and their guests ¶ Catch-and -release fishing only ** The only pond open to fishing on Hurlburt Field †† Fishing is not allowed Source: Eglin AFB 2000b |
|||
| Hurlburt¶,** | ||||
Nearby Off-Base Areas
Tom's Bayou is in Valparaiso, Florida, and receives drainage from surface water bodies on Eglin Main Base. People reside around Tom's Bayou and engage in various recreational activities in the bayou (e.g., fishing, swimming, and boating). While fishing and crabbing occur in the bayou, harvesting shellfish is not approved by FDEP (personal communication with Florida Department of Health personnel, September 2002). Several IRP sites were identified within the Tom's Bayou drainage basin (see Figure 3).
Three significant hydrogeologic units underlie Eglin Reservation: the surficial sand and gravel aquifer, the Pensacola Clay confining layer, and the Floridan aquifer (EA Engineering, Science, and Technology 1997). Groundwater flow in the sand and gravel aquifer is toward larger streams or the Choctawhatchee Bay. The Pensacola Clay is a thick confining layer that hydraulically isolates the sand and gravel aquifer from the Floridan aquifer. The Floridan aquifer is recharged to the north of Eglin AFB where the Pensacola Clay is thinner or absent. Groundwater flow in the Floridan aquifer is south toward the Gulf of Mexico (EA Engineering, Science, and Technology 1997).
Groundwater Use
On-Base
Eglin AFB receives its drinking water from deep groundwater wells (about 600 feet below mean sea level) that draw water from the Floridan aquifer, the primary source of public water in northwest Florida (EA Engineering, Science, and Technology 1997). As noted above, the Pensacola Clay forms a competent confining layer between the surficial aquifer and the Floridan aquifer. There are approximately 111 water supply wells on the Eglin Reservation. Twenty active wells are located on Eglin Main Base and another 20 wells have been capped, abandoned, or are inactive (EA Engineering, Science, and Technology 1997). The remaining 61 wells are assumed to be in areas other than the Main Base and active since they have not been categorized as capped, abandoned, or are inactive.
Off-Base
The majority of residents living near Eglin AFB are supplied with public water from Okaloosa County, Niceville, or Valparaiso water supplies. Some people use private groundwater wells and some communities or businesses have limited use commercial or community systems that require a permit from the Florida Department of Health (personal communication with Florida Department of Health personnel, September 2002).
ATSDR investigated a contaminated groundwater plume originating from the C-6 Radar Facility. The nearest downgradient drinking water wells from this site are located off base, 3 miles south, in the town of Portland, Florida. The extent of the trichloroethylene (TCE) contamination was defined to be entirely on Eglin AFB property. To ensure that the contamination does not migrate to Portland, the Air Force conducts long-term monitoring of the groundwater at the site on an annual basis (Earth Tech 2000a).
E. Quality Assurance and Quality Control
In preparing this public health assessment, ATSDR reviewed and evaluated information provided in the referenced documents. Documents prepared for the IRP program must meet specific standards for adequate quality assurance and control measures for chain-of-custody procedures, laboratory procedures, and data reporting. The environmental data presented in this public health assessment are from the referenced reports. The limitations of these data have been identified in the associated reports. After evaluating the data, ATSDR determined that the quality of environmental data available in site-related documents for Eglin AFB is adequate to make public health decisions.
II. EVALUATION OF ENVIRONMENTAL CONTAMINATION, EXPOSURE PATHWAYS, AND PUBLIC HEALTH IMPLICATIONS
ATSDR evaluated a number of areas identified by the petitioner and other community members to determine whether potential exposure to contaminated media would result in past, present, or future public health hazards. ATSDR identified five main ways people were concerned that they would be exposed to hazardous levels of contaminants. Table 1 provides a summary of the exposure pathways at Eglin AFB that were evaluated in this public health assessment. Figures 2 and 3 provide the locations of the sites evaluated. For reference, Appendix A defines some of the technical terms used in this public health assessment and a List of Acronyms is available after the Table of Contents.
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OUTLINE OF IDENTIFIED EXPOSURE CONCERNS
|
ATSDR obtained information characterizing the magnitude and duration of relevant chemical releases from Eglin AFB, including those from herbicide spraying, OB/OD activities, prescribed burns, wildfires, and a past structural fire (C-6 Radar Facility). Figure 2 shows the site locations.
ATSDR determined that previous herbicide spraying activities, current OB/OD operations, and a past structural fire did not pose public health hazards. Contaminant levels in off-base residential areas would have been much lower than levels shown to cause adverse health effects.
In order to address whether on-base
prescribed burns or wildfires pose a health
hazard to off-base residents ATSDR
considered two different aspects of on-base
fires. First, an evaluation of whether fires in
areas where soil contamination exist could
cause contaminants to become air-borne and
be transported to off-base residential areas.
Next, a consideration of exposure to
contaminants released during the burning of
plant material (trees, grasses, shrubs, etc.).
Findings indicate that the contaminants in soils (depleted uranium and herbicides, including Herbicide Orange(4)) would not reach off-base areas at levels associated with harmful health effects. Therefore, off-base residents would not come in contact with those contaminants.
Still, the burning of plant material causes a release of particles and natural combustion products (smoke) that could cause some short-term adverse health effects (e.g., burning, itching or watery eyes, nausea, breathing difficulty and asthma-like symptoms) in those people exposed. Airborne emissions from prescribed burns and wildfires have not been measured. This evaluation is based on health effects seen from other burns. Individuals highly sensitive to the effects would be anyone with previous respiratory conditions such as asthma or emphysema, children, and the elderly. Health effects would likely be of short duration, developing within a few days of exposure and lasting no more than 2 or 3 weeks after exposure stopped. The base takes several measures to minimize the impacts of fires on residential neighborhoods. Fires can, however, present a public health hazard to people who are sensitive to the effects of smoke.
Herbicides and pesticides have been sprayed at locations throughout Eglin AFB periodically for at least 40 years (Eglin AFB 2000c). Winds might have blown some of these chemicals to off-base locations. Measuring airborne levels of these chemicals is not a general practice and not required by regulation. Thus, airborne levels of herbicides or pesticides have never been measured in residential areas. To evaluate this concern, ATSDR estimated exposures based on what was sprayed, the distance to populated areas, and the wind speed and direction.
The base does not have comprehensive records that document exactly when, where, and the quantity of chemicals sprayed throughout the base. But it does have records that summarize spraying activities for the Herbicide Exposure Unit, where herbicides were sprayed from 1962 to 1970 (Eglin AFB 2000c) (for more details about this site see the Herbicide Exposure Unit discussion in the Herbicide Contamination concern). Though pesticides and herbicides have been, and continue to be, sprayed in other areas of the base, the amounts sprayed are notably lower when compared to those sprayed at the Herbicide Exposure Unit. Therefore, this evaluation is conservatively based on air exposures resulting from spraying activities at the Herbicide Exposure Unit–the area on Eglin AFB believed to be sprayed with the greatest quantities of potentially toxic chemicals.
ATSDR evaluated a simple and overestimated exposure situation: What would have happened if the entire amount of chemicals used at the Herbicide Exposure Unit continuously blew directly toward the closest off-base location, instead of mostly depositing on the ground at the Herbicide Exposure Unit? Though obviously unrealistic, this scenario provides an extreme upper bound estimate of what the actual ambient air concentrations might have been during relatively intense spraying activities.
ATSDR used an air dispersion model (the SCREEN3 Model; EPA 1995) together with Eglin AFB chemical use data to estimate off-base air concentrations at the nearest base boundary (about 2 miles). The model, agency assumptions, and the results are described in Appendix B. Even with the extremely conservative assumptions in this analysis, the estimated average off-base concentrations were lower than levels expected to be harmful to humans. In other words, spraying activities at the Herbicide Exposure Unit did not cause concentrations of chemicals to reach levels of health concern at off-base locations. For example, the estimated average air concentration for arsenic at off-base locations (0.009 micrograms per cubic meter, or µg/m3) is substantially lower than levels expected to be harmful to humans (0.7-613 µg/m3; ATSDR 2000a). Further, this estimated arsenic concentration overstates the actual air concentration, that is ATSDR used the extremely conservative assumption that all of the arsenic that was sprayed at the Herbicide Exposure Unit blew directly to, and only to, off-base locations. See Appendix B for ATSDR's evaluation of additional chemicals sprayed at the Herbicide Exposure Unit.
Past herbicide spraying at the Herbicide Exposure Unit does not appear to have posed a past public health hazard. Therefore, current and future spraying activities, which use notably lower amounts and less toxic mixtures than past herbicide spraying, are not expected to pose current or future public health hazards to off-base residents.
In October 1996, Eglin AFB obtained a permit to conduct OB/OD operations at Range C-62 and
Range C-52N (EA Engineering, Science, and
Technology 1999). These ranges are located in the
northeast and east central sections of Eglin
Reservation, respectively (see Figure 2). Range C-62 is about 14,500 feet from Eglin's east boundary
and Range C-52N is about 25,000 feet from Eglin's
north boundary. Range C-62 contains OB/OD units
in the south-central portion of the range and Range
C-52N contains an OD unit in the middle of the range.
From October 1997 to October 1998, the Air Force monitored six OB/OD events at Range C-62 for total suspended particulates (TSP), barium, magnesium, and lead–all of which were previously identified during a human health risk assessment as the air quality compounds of concern. Ambient air sampling activities were pre-approved by EPA and FDEP (EA Engineering, Science, and Technology 1999).
The upwind and downwind ambient air samples showed that the chemical concentrations in the air did not exceed EPA's National Ambient Air Quality Standards (NAAQS) for TSP (75 µg/m3) and the Florida ambient reference concentrations (ARCs) for barium (1.2 µg/m3), magnesium (24 µg/m3), and lead (0.09 µg/m3); with the exception of one lead sample (0.15 µg/m3) during one event (EA Engineering, Science, and Technology 1999). But, average lead results (0.03 µg/m3) were below Florida's ARCs for lead.
The air quality monitoring was conducted within the range and the airborne contamination is expected to be substantially dispersed before reaching residential neighborhoods. The chemicals released during OB/OD operations are at levels too low to be of health concern on base and are not expected to be concentrated in off-base areas. Therefore, they pose no health hazard to off-base populations.
Prescribed Burns
To reduce the likelihood and severity of wildfires, base personnel have since the 1900s conducted periodic prescribed (i.e., controlled) burns of vegetation (Eglin AFB 1999). Most open areas of Eglin AFB are burned at least once every 10 years through a series of prescribed burns. These burns normally are conducted in the spring, and sometimes in the fall. Each individual burn typically lasts less than 24 hours and spans an area of 1,500 acres or less (Eglin AFB 1997-98).
To prevent smoke plumes from reaching residential neighborhoods, the base approves prescribed burns only after detailed computer simulations show that potential impact of the fire on nearby residents is minimal (Eglin AFB 1999). Eglin AFB conducts prescribed burns under controlled conditions and follows procedures outlined in the US Forest Service's A Guide for Prescribed Fires in Southern Forests, which describes appropriate weather conditions, fire ignition methods, and other parameters for conducting successful prescribed burns and minimizing their adverse environmental effects. The Guide emphasizes the importance of managing smoke and avoiding risk to smoke-sensitive areas to the greatest extent possible (USFS 1989). According to EPA, prescribed burns are generally accepted as an "ecologically sound tool for forest, range, and wetland management," and prescribed burns are believed to release a "relatively smaller quantity" of air pollution than wildfires (EPA 1996).
Beginning in 2001, Eglin officials committed to improving the ways they inform the community when prescribed burns are scheduled (Daily News 2000b). Notifying potentially impacted community members, especially sensitive populations, through timely and informative press releases and radio announcements when the prescribed burns are scheduled affords these populations the opportunity to reduce potential exposures.
Wildfires
Wildfires occur in many parts of Florida, including Eglin AFB. Severe wildfires can spread over larger areas, and burn for durations much longer than those of typical prescribed burns. Therefore, wildfires are capable of producing a much greater volume of air pollution than prescribed burns. Furthermore, wildfires can have greater impacts on residential areas near Eglin AFB than prescribed burns, primarily because wildfires can occur when winds are blowing in any direction. Given the base's policy of conducting regular prescribed burns to minimize the consequences of wildfires, however, the chance that a severe wildfire would occur at Eglin AFB is very low (especially in comparison to other parts of Florida where prescribed burns are not practiced).
Components of Air Releases from Fires
To determine the health impact of prescribed burns or wildfires on nearby residents and workers, ATSDR relied on information from other forest fires and wildfires across the country to determine possible components of the fire and smoke at Eglin AFB. Additional information about the fire components possibly released into the air were also ascertained from surface soil contaminants (e.g., herbicides and depleted uranium) found at Eglin AFB.
The main components of fire that could pose the greatest hazard by way of inhalation are carbon monoxide, carbon dioxide, aldehydes (i.e., formaldehyde and acrolein), ozone, and respirable particulates.
Carbon Monoxide: Carbon monoxide is a colorless, odorless gas released during incomplete combustion (i.e., fire) which primarily affects the nervous system. Exposure to carbon monoxide can cause headaches, dizziness, and lightheadedness. Exposure to low to moderate levels can affect concentration, cause memory and vision problems, loss of muscle coordination, temporary reduction in lung function, bronchitis, and asthma-like symptoms (New Jersey Hazardous Substance Fact Sheets; Ottmar and Reinhardt 1989; Reinhardt et al. 1999; Sharkey 1997).
Carbon Dioxide: Carbon dioxide is a colorless, odorless gas which, in addition to being a component released during fire, is released by our bodies when exhaled. Exposure to moderate amounts of carbon dioxide can cause lightheadedness, confusion, and loss of consciousness (New Jersey Hazardous Substance Fact Sheets).
Formaldehyde: Formaldehyde is a colorless, flammable gas with a strong, pungent odor. It can form explosive mixtures with air and oxygen. As an important industrial chemical of major commercial use, formaldehyde is found throughout the environment. It is also naturally produced in very small amounts in our bodies as part of our normal, everyday metabolism (ATSDR 1999a). In solution, it has a wide range of uses. Examples include the manufacture of resins and textiles, disinfectants, and laboratory fixatives or preservatives. Formaldehyde is formed during incomplete combustion of hydrocarbons (Reinhardt and Ottmar 2000). In outdoor air it can originate from many sources such as incinerators, photochemical smog, and engine exhaust. Atmospheric levels of formaldehyde have been reported to range from less than 0.005 ppm to 0.06 ppm near industrial outlets or in areas of heavy smog (Reinhardt et al. 2000). Workers who smoke are exposed to additional levels of formaldehyde, cigarette smoke contains as much as 40 ppm of formaldehyde by volume (Sharkey 1996). The first signs or symptoms noticed from exposure to formaldehyde at concentrations ranging from 0.1 to 5 ppm are burning of the eyes, tearing, and general irritation to the upper respiratory passages. Higher exposures (10 to 20 ppm) could produce coughing, tightening in the chest, a sense of pressure in the head, and palpitation of the heart (NIOSH 2000; New Jersey Hazardous Substance Fact Sheets; Reinhardt et al. 1994; USDA 1999).
Acrolein: Acrolein is a colorless to yellow liquid that produces vapors characterized by a foul choking odor. It is released from the burning of natural materials, such as plants. People can also breathe acrolein when near automobiles, because burning gasoline forms acrolein, which enters the air (New Jersey Hazardous Substance Fact Sheets; Reinhardt and Ottmar 2000; Reinhardt et al. 2000). Oil or coal power plants also release small amounts of acrolein. Acrolein is formed when fats are heated. Small amounts of acrolein can also be found in foods such as fried foods, cooking oils, and roasted coffee. In several large cities acrolein has been measured at levels of 0.009 ppm (Reinhardt et al. 1994). The levels in inside air can be much higher when tobacco is burning. For example, in a car with three people smoking and the windows closed, a person could breathe in 0.300 ppm. Acrolein can be smelled at levels above 0.160 ppm. Thus, a person smelling acrolein would probably notice eye, nose, and throat irritation before any lung damage occurred (Reinhardt et al. 1994).
Ozone: Ozone is a colorless gas with a sharp odor which can be smelled well below the permissible levels of exposure. At low exposure doses, an individual could experience irritation of the eyes, dryness of the nose and throat, and a cough. At moderate levels, headache, stomach ache and vomiting can occur. In addition, ozone is the main component in smog that can cause breathing problems, aggravate asthma, and increases the severity and incidence of respiratory infections (New Jersey Hazardous Substance Fact Sheets; Reinhardt et al. 1999).
Particulates: Particulates are small pieces of material released from combustion or from physical release. The effect particulates have when breathed in depends on the size of the particles. Larger particles (greater than 10 microns) get trapped by the nasal passages. Particles greater than 5 microns travel down the airway to the bronchioles and are removed by the cilia and by coughing. Respirable particles (0.5-5 microns) can travel deeper into the alveolar region of the lungs causing irritation, bronchitis and respiratory effects. Many particles smaller than 0.5 microns remain suspended in the air and are exhaled, however some are deposited in the alveolar region (Levy and Wegman 1988; Williams et al. 1985). These smaller particles are cleared by macrophages, lymphatics, and the bloodstream (Amdur et al. 1991). The legal airborne permissible exposure limit for workers is 50 ppm averaged over an 8-hour period (Reinhardt et al. 1994).
Other Chemical Considerations: If fires reach sufficiently high temperatures, they can also cause contaminants in soils, like metals and herbicides, to become airborne. Therefore, depending on the location of a fire, smoke from the fires can also contain metals and other pollutants. As a hypothetical example(5), ATSDR evaluated whether a wildfire near the Herbicide Exposure Unit could release trace amounts of the chemicals that were tested in this area to the air, assuming that they are in the soil. To evaluate the public health implications of these emissions, ATSDR considered an extremely conservative exposure situation to determine whether smoke contains unhealthy levels of contaminants that were once in the soil(6). From such analyses, ATSDR concluded that soil contaminants that might be released during wildfires are not expected to reach levels associated with adverse health effects at off-base locations. Appendix B contains more details about how this conclusion was reached.
Depleted Uranium: Depleted uranium (DU) describes a waste product from the production of nuclear fuel for energy production or weapons. Typically DU is approximately 50% less radioactive than naturally occurring uranium, yet it is just as dense. This density allows the waste material to be used in military applications such as armor and armor piercing munitions. During the use of DU munitions at Eglin, the areas where the DU were used was localized and studies suggest the majority of the DU remains in the areas (White 1981; Becker and Vanta 1995).
If the DU is in fine particles in the surface soils, it would have oxidized either by the original use of the munitions or by exposure to the environment. Uranium oxides do not vaporize (Moses 1978). Because DU particles are extremely dense, any particles in the soil that could get airborne would quickly settle to the ground in the area of use. Conceivably, very small particulates could disperse at greater distances from the source. However, deposition of these fine particles would be widely scattered, and consequently, measurable amounts of DU would not occur in localized areas distant from the source (ATSDR 1997). Also, if the DU is in large metal pieces, it would not get airborne during a prescribed burn or wildfire. Studies suggest that the munitions (large DU metal pieces) penetrated the ground surface to a depth of 6 inches (Earth Tech 2001b) which, if a prescribed burn or wildfire occurred, would not result in temperatures sufficient to affect the DU metal. Also, plants in the area would not be contaminated with uranium since uranium is minimally transferred from soil to vegetation (the uranium transfer factor from soil to vegetation is 0.0085); therefore, burning vegetation would not contribute to airborne DU (Baes et al. 1984).
Public Health Implications
The likelihood of becoming sick from chemical exposure increases as the amount of chemical exposure increases. This is determined by the length of time and the amount of chemicals to which someone is exposed. Short-term exposure typically refers to contact with a contaminant (e.g., by breathing it in, eating or drinking it, or touching it to the skin or eyes) for a short period of time, less than 1 year. Long-term exposure typically refers to contact with a contaminant for more than one year (New Jersey Hazardous Substance Fact Sheets; Reinhardt and Ottmar 2000; Sharkey 1996). Short-term health effects (also called acute health effects) are conditions, symptoms, or health changes that can occur immediately or shortly after exposure and last for less than 2 to 3 weeks (New Jersey Hazardous Substance Fact Sheets; Reinhardt and Ottmar 2000; Sharkey 1996). Long-term health effects (also called chronic health effects) are conditions, symptoms, or health changes that can occur at some time after exposure and can last for months or years. Short-term health effects can occur from exposure to high or low amounts of chemical contaminants and can also occur from short- or long-term exposures. Most long-term health effects, however, result from repeated exposures to a chemical (New Jersey Hazardous Substance Fact Sheets).
Health-related research shows that firefighters can experience both reversible, short-term health effects, such as eye and respiratory tract irritation, and long-term adverse health effects, such as decreased lung function and increased incidence of respiratory illness (Reinhardt 1991; Reinhardt et al. 1995; Reinhardt and Ottmar 1997). Long-term adverse health effects have been seen in a small portion of firefighters who were exposed to fire components on a daily basis for more than 1 year (Reinhardt 1991; Sandber 1999; Sharkey 1999). Data from studies show that between 1 and 10% of firefighters have exposures to fire and smoke components which exceed recommended Time Weighted Averages(7) for a normal 8-hour day/40 hour work week. Less than 5% of these smoke exposures exceed Occupational Safety and Health Administration (OSHA) permissible exposure limits, which are less stringent than the recommended limits, but which are legally applicable to federal agencies (Sharkey 1999). The exposures of firefighters to smoke and fire components have been identified by both the respired air from the lungs of firefighters and from actual air samples collected by monitors worn on the neck and chest of firefighters. Reports of studies conducted since 1988 show consistent results. In several studies, firefighters, who were given questionnaires after days of exposure, reported headaches, cough, shortness of breath, lightheadedness, and wheezing (Ottmar and Reinhardt 1989; Reinhardt et al. 1999; Reinhardt 1991; Sandber 1999).
Airborne emissions from prescribed burns and wildfires have not been measured in the counties surrounding Eglin AFB. Nevertheless, to provide perspective about health problems reported in the general population, ATSDR spoke with nurses from several counties where severe wildfires occurred during 2000. Most of the fire and smoke related cases reported eye, nose, and throat irritation that subsided within a few hours after exposures stopped. None of the county nurses reported adverse pregnancy or birth outcomes related to the fire and smoke. They noted that most phone calls were not related to health, but to how to get the smell of smoke out of the furniture and carpeting (ATSDR 2000c, 2000d, 2000e, 2000f, 2000g, 2000h).
That said, however, recent studies suggest that the incidence of certain acute respiratory health effects (e.g., asthma-like symptoms, acute bronchitis, and chest pain) among selected Florida residents is greater when large wildfires occur, as compared to when wildfires do not occur or are less severe (CDC 1999). The likelihood of observing these effects during a prescribed burn is believed to be much reduced because the base makes every effort to conduct prescribed burns only during meteorological conditions that favor rapid dispersion of smoke in directions away from residences. In addition, once emitted by fires, these pollutants gradually disperse as smoke plumes blow downwind.
Even though Eglin AFB takes several measures to minimize the impacts of fires on residential neighborhoods, components (chemical and physical) released from prescribed burns and wildfires could cause some short-term adverse health effects (such as burning, itching, or watery eyes and sinuses; headache; nausea; breathing difficulty; and asthma-like symptoms) in those people exposed, especially sensitive populations (such as anyone with previous respiratory conditions such as asthma or emphysema, children, and the elderly). Although, health effects would be of short duration, developing within a few days of exposure and lasting no more than 2 or 3 weeks after exposure stopped.
The Air Force should continue to notify community members when the prescribed burns are scheduled. This allows people to take measures to reduce potential exposures. If people are experiencing respiratory problems, they should seek the attention of their personal medical care provider.
The C-6 Radar Facility was built in the mid-1960s to monitor the southeastern United States airspace (Earth Tech 2000a; Eglin AFB 2000c). It is located in the eastern portion of Eglin AFB, approximately 3 miles north of the town of Portland in an undeveloped section, see Figure 2 (Earth Tech 2000a). On January 5, 1965, during the final phases of its construction, the main building of the C-6 Radar Facility caught fire and was destroyed (Rust International 1996; Eglin AFB 1999, 2000). The main building was made of wood, but it housed high-voltage transformers and radar/surveillance equipment that contained polychlorinated biphenyls (PCBs) and other environmentally persistent materials (Earth Tech 2000a; Rust International 1996).
There are conflicting reports of the remedial activities following the fire. An Eglin employee in charge of operations reported that the entire facility and contents (e.g., transformers and radar/surveillance equipment) were buried in an unlined pit in the front of the remaining foundation slab. A second employee claimed to be an eyewitness to the disposal activities, reported that most of the recyclable materials were removed from the site and only inert debris (e.g., concrete fragments and steel beams) were buried on site (Earth Tech 2000a; Rust International 1996).
Because the fire at the C-6 Radar Facility lasted only 1 day, inhalation exposures to contaminants from this fire, if any, were short term. No air sampling was conducted in the vicinity of the C-6 Radar Facility during or after the fire, and a detailed inventory of the original contents of the main building is not available.
Some observations can help put potential exposures from this fire into perspective. For instance, meteorological data collected at a nearby air field on Eglin AFB indicate that wind blew predominantly from the east and northeast (or toward the west and southwest) on the date of the fire, thus suggesting that residents southwest of the site could have been briefly exposed to the smoke from the fire (NOAA 1965). Because the C-6 Radar Facility is 19,260 feet from the nearest boundary of the base (about 3 miles from Portland), contaminants in the smoke that reached residential neighborhoods were expected to be substantially dispersed and not concentrated. Though neither of these observations quantify actual exposures to smoke and fumes from the fire, they both suggest that the fire had little impact on residential neighborhoods near the C-6 Radar Facility.
B. Concern: Surface Water Contamination
To address this concern, ATSDR obtained information that characterizes the nature and extent of contamination and the potential for human exposure at the following surface water bodies: Tom's Bayou; Weekly Pond; Pocosin Pond; Mullet, Trout, and Basin Creeks; and an unnamed pond near North Gate; see Figures 2 and 3 for site locations.
ATSDR determined that although contamination from Eglin AFB is potentially migrating into Tom's Bayou, it would not cause a past, present, and future public health hazard for people living near, recreating in, or eating fish from Tom's Bayou.
ATSDR determined that eating fish from Weekly and Pocosin Ponds is not likely to present a past, current, and future public health hazard. As a precautionary measure, fishing is currently not allowed in Pocosin Pond and is designated as catch-and-release only in Weekly Pond. Based upon the available information, ATSDR determined that people who ate fish from Weekly Pond in the past were not exposed to unsafe levels of chemicals.
Recreating in Mullet, Trout, and Basin Creeks is also not likely to present a public health hazard because the chemicals detected in the surface water, sediment, and fish tissues were below levels of health concern.
One community member wanted information on whether Herbicide Orange was present in an unnamed pond near the North Gate of Eglin Main Base. The Air Force has no records of Herbicide Orange in this unnamed pond. Access to the unnamed pond near the North Gate is currently limited by the location of the pond and the presence of building rubble between an off-base stable and the pond; thus any potential exposures would have been minimal.
Tom's Bayou is in Valparaiso, Florida, and is used for various recreational activities (e.g., fishing, swimming and boating) by those who reside near the bayou. There are several small ponds and streams located on Eglin Main Base to the south and west of Tom's Bayou, which drain into the bayou (e.g., small unnamed beaver ponds to the south and Tom's Creek to the west). Several IRP sites are at the headwaters or along these surface water bodies, potentially contributing to contamination in Tom's Bayou (see Figure 3). Table 2 provides site descriptions and remedial activities for these IRP sites. For the purposes of this evaluation, these sites were grouped into four areas according to location and flow into Tom's Bayou. These sites range from about 2,000-11,000 feet upstream of the bayou.
ATSDR extensively investigated whether any sampling had been conducted in Tom's Bayou. The US Fish and Wildlife Service, as part of Eglin AFB's stream monitoring program, collected water quality data in Tom's Bayou, including dissolved oxygen levels, turbidity, and conductivity. They have also collected aquatic insects to determine taxa richness and diversity. Based on the information collected, Tom's Bayou is considered to be a healthy system (personal communication with US Fish and Wildlife Service personnel, April 2002).
In February 1997, FDEP sampled a site in Tom's Bayou during an environmental assessment of sediment quality in Boggy Bayou (Butts 1997). FDEP collected water quality data in Tom's Bayou and reported that the results indicate good water quality (with the exception of nitrate plus nitrite levels, however, according to ATSDR's evaluation the concentrations are below levels of health concern). FDEP also collected two sediment samples from Tom's Bayou and analyzed them for metals and volatile organic compounds. ATSDR reviewed the analytical data and determined that the chemical concentrations present in the sediment are not at levels of health concern for people using Tom's Bayou for recreational activities (i.e., all the concentrations were detected below levels known to cause harmful health effects, assuming that people were exposed to the chemicals present every day for 70 years, see Appendix C for more details about how ATSDR reached this conclusion). Finally, FDEP also evaluated the benthic macroinvertebrate community structure at the sample location in Tom's Bayou and reported a good assemblage of organisms present, especially in the more productive shallow zone (Butts 1997).
Because limited chemical data are available for Tom's Bayou, ATSDR evaluated the level of contamination present at the Eglin AFB sites located in the drainage basin that potentially contribute to contamination in Tom's Bayou. As a conservative approach, ATSDR assumed that the contaminant concentrations present at these sites are equivalent to the level of contamination that people are being exposed to in Tom's Bayou, even though these areas of Eglin Main Base are closed to all forms of recreation (Eglin AFB 2000b). ATSDR evaluated whether exposure to these contaminant concentrations could result in exposure levels high enough to cause harmful health effects, assuming people were being exposed every day for 70 years. Appendix C describes in greater detail the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects.
The Air Force has conducted several investigations at many of the IRP sites within the Tom's Bayou drainage basin. ATSDR determined that the available information adequately defines the extent of the contamination at the sites in the drainage basin and can be used to evaluate health concerns in the bayou.
In summary, ATSDR determined that all of the chemicals detected at the four areas that drain into Tom's Bayou are below levels of health concern and would not cause harmful health effects in people using Tom's Bayou for recreational activities in the past, present, and future. ATSDR's conclusions are based on calculated exposures that overstate actual exposures occurring in Tom's Bayou because (1) people are not expected to be exposed consistently to the maximum concentration on a daily basis and for an extended period of time. More realistically people would encounter a range of concentrations, including no concentrations, given that every chemical was not detected in every sample, (2) adults and children are not expected to be recreating in the bayou as often as 365 days of the year, and (3) the majority of the data are from sites that are located on Eglin Main Base and it is expected that the concentrations would be lower in the bayou than at the source areas.
It should be noted that ATSDR considered exposure to multiple chemicals during this evaluation. Several studies, including those conducted by the National Toxicology Program in the United States and the TNO Nutrition and Food Research Institute in the Netherlands, among others, generally support the conclusion that if each individual chemical is at a concentration not likely to produce harmful health effects (as is the case here), exposures to multiple chemicals are also not expected to be of health concern (for reviews, see Seed et al. 1995; Feron et al. 1993).
Fish from Tom's Bayou have not been sampled and analyzed for contamination. Without actual data, ATSDR can not definitively draw conclusions about whether eating fish from the bayou would be expected to cause harmful health effects. Still, based on the available information about the water and ecosystem quality in Tom's Bayou and the type of contamination present at the IRP sites within the drainage basin, ATSDR does not expect high levels of contamination to accumulate in fish in the bayou. FDEP and US Fish and Wildlife Service conducted water quality surveys in Tom's Bayou and concluded that the water quality is good and that the bayou is a healthy system, ecologically. The levels and types of contamination found at the sites on Eglin Main Base do not pose a health hazard to people, including those exposed directly to the contamination.
Weekly Pond is a small 6-acre pond located southeast of the runways on Eglin Main Base (see Figure 3). The pond is about 4,460 feet from the Lewis Junior High School, which is just outside Eglin AFB's East Gate (Eglin AFB 2001b). Fishing is limited to Air Force personnel and their guests, and Eglin AFB's Natural Resources Branch requires a permit to fish on base (Eglin AFB 2000b). While Weekly Pond was open to recreational fishing in the past, it currently has a catch-and-release policy with signs posted (Water and Air Research 1984). In 1996, the Natural Resource Department found trace amounts of dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) in fish samples. Even though the levels were below health concern, Weekly Pond was posted catch-and-release as a precautionary measure. Also, Eglin AFB was concerned that new quantities of contaminants from a nearby landfill could increase levels in the future (personal communication with Eglin AFB personnel, July 2002).
ATSDR evaluated whether contaminant concentrations could result in exposure doses high enough to cause harmful health effects in people who in the past might have eaten fish from Weekly Pond. In the mid-1980s, Eglin AFB sampled fish tissue and detected pesticides (DDT, DDD, and DDE) (Eglin AFB 1989). Other contaminants have not been identified in Weekly Pond. To calculate exposures, ATSDR assumed that adults and children ate seven meals of fish from Weekly Pond each month (adults were estimated to eat 8 ounces of fish every meal and children were estimated to eat 4 ounces of fish every meal). The resulting exposure doses were well below levels of health concern when compared to values documented in the medical, toxicologic, and epidemiologic literature (ATSDR 2000b). Therefore, adverse health effects are not expected to have occurred from eating fish from Weekly Pond in the past. Thus, while exposure was possible, Weekly Pond poses no past public health hazard. Additionally, because people are not allowed to eat fish from Weekly Pond, people are not being exposed, and no current or future public health hazard is present. Appendix C describes in greater detail the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects.
Pocosin Pond covers approximately 10-13 acres and is in the north-central section of the Eglin Reservation (see Figure 2), about 32,000 feet from the nearest base boundary (Earth Tech 2001b; Eglin AFB 2001b). In the past, the Air Force used this area for jungle-environment ballistic testing, air drops, and static detonation of conventional munitions (USACE August 1999 as cited in Earth Tech 2001b). Sometime between July 1969 and February 1970, during one exercise, approximately 500 rounds of DU ammunition were fired at a cloth target marker located in the middle of Pocosin Pond (Earth Tech 2001b).
Pocosin Pond is located in an area open to the public during designated hunting seasons but is restricted to the use of primitive weapons only; however, the thick brush surrounding the pond makes it unlikely that hunters would actually use the area near the pond (Earth Tech 2001b; Eglin AFB 2000b). Members of the Natural Resources Branch and US Fish and Wildlife Service sampled fish and amphibians in 1997. Pocosin Pond was found to be very acidic and no fish were present at that time (personal communication with Eglin AFB personnel, July 2002). Fishing is not allowed at Pocosin Pond and signs are posted to notify the public.
The Low-Level Radioactive Materials Partnering Team recommended No Further Action for the site with current land use controls in place. Even though DU fragments were not removed, the partnering team decided that further investigation would be impractical due to (1) the minimal number of rounds used, (2) the remoteness of the pond, (3) the thickness of the brush, and (4) the expense to remove the brush (Earth Tech 2001b).
Pocosin Pond receives surface water runoff from the area surrounding the Cattle Dipping Vat (OT-83; formerly AOC-113), which is located about 230 feet south of the pond. The cattle dipping vat was used from 1917 to 1944 during the National Cattle Tick Fever Eradication Program (Woodward-Clyde 1995 as cited in Eglin AFB 2000a). The cattle dip solutions commonly consisted of sodium carbonate, arsenic trioxide, pine tar, and water (Eglin AFB 2000c). Arsenic in soil is the primary contaminant detected at the Cattle Dipping Vat. In 1998, the Air Force excavated arsenic-contaminated soil and the concrete vat to remove the source of contamination. The Air Force recommended No Further Investigative Action with current land use controls for this site (Eglin AFB 2000a).
In general, the procedure used during a Preliminary Assessment in October 2000 to evaluate the levels of radioactivity associated with the Pocosin Pond area did not detect any radioactive material or radiation levels elevated above the investigation limit and, by definition, above natural background levels in site soils and dry sediments of Pocosin Pond (Earth Tech 2001b). In addition, documentation exists suggesting that the DU has not migrated from the area (Becker and Vanta 1995; White 1981). Furthermore, no visual evidence of depleted uranium fragments were found in or around a 50 to 100-foot perimeter of the pond. But because the penetrators could have been below the ground surface, this is not surprising. The surveyors also noted that the thick trees and brush surrounding Pocosin Pond make it unlikely that DU fragments would be found (Earth Tech 2001b).
Additionally, surface water and sediment samples were taken from Pocosin Pond as part of a Resource Conservation and Recovery Act (RCRA) Facility Investigation for the Cattle Dipping Vat. Contaminants were not detected above screening levels (Eglin AFB 2000a). Most importantly, Pocosin Pond is located in an area only open to licensed hunters during designated hunting seasons and fishing is not allowed (see the Community Concern section for a discussion about eating venison caught in the vicinity of the Eglin Reservation). Therefore, because people are not allowed to catch and eat fish from Pocosin Pond and no appreciable contamination exits, Pocosin Pond poses no public health hazard.
Mullet, Trout, and Basin Creeks are in the southeastern section of the Eglin Reservation (see Figure 3) and receive surface water runoff from the Herbicide Exposure Unit (i.e., C-52A Herbicide Test Grid (SS-25) and the Mullet Creek Drum Disposal Site (DP-09)) and the C-52A Aerial Overspray Area (AOC-24). For more details about these sites see the Herbicide Contamination section of this document. The headwaters of all three creeks are located in areas closed to all forms of public access, but flow into areas that are open to seasonal recreational activities (with appropriate Eglin AFB permits). Mullet and Trout Creeks flow through the Fred Gannon Rocky Bayou State Recreational Area and all three creeks eventually drain into the Choctawhatchee Bay.
According to the Baseline Risk Assessment, none of the creeks are visited very often (EA Engineering, Science, and Technology 1997). The highest use was characterized as one or more persons visiting the area seasonally for Basin Creek (downstream of the Herbicide Exposure Unit) and lower Mullet Creek. The headwaters of Mullet Creek(8) and lower Trout Creek are visited even less (1 or more people annually) and the headwaters of Trout Creek are not expected to receive visitors (EA Engineering, Science, and Technology 1997).
The Air Force sampled surface water, sediment, and fish from Mullet, Trout, and Basin Creeks for organic compounds, pesticides and herbicides, dioxins and furans, PCBs, and inorganics (EA Engineering, Science, and Technology 1997; Engineering-Science 1993). Because contamination is present and people do have contact with the surface water, sediment, and fish in these creeks, ATSDR evaluated whether concentrations of chemicals were at levels that would be expected to cause harmful health effects in people who might swim, wade in, or eat fish from the creeks.
To determine if people were, are, or will be exposed to unsafe levels of the chemicals present, ATSDR calculated recreational exposure to the maximum concentrations detected in the surface water and sediment by conservatively assuming that adults and children visit the creeks 365 days/year, even though actual exposure is much lower (EA Engineering, Science, and Technology 1997). ATSDR also calculated exposure doses for catching and eating fish from the creeks by assuming that adults and children consume seven meals of fish from the creeks each month (adults were estimated to eat 8 ounces of fish every meal and children were estimated to eat 4 ounces of fish every meal). Appendix C describes in greater detail the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects.
The resulting exposure doses were below levels of health concern when compared to values documented in the medical, toxicologic, and epidemiologic literature (ATSDR 2000a, 2002a; EPA 2002). For instance, the estimated dose from recreational exposure to the maximum concentration of arsenic in the surface water is 6.4 x 10-6 milligrams per kilogram per day (mg/kg/day) for adults and 2.8 x 10-5 mg/kg/day for children, which are orders of magnitude below doses known to cause harmful cancer and noncancer health effects (0.01 to 0.05 mg/kg/day; ATSDR 2000a). Further, the calculated exposures overstate the actual exposures occurring at Mullet, Trout, and Basin Creeks because (1) people are not expected to be exposed consistently to the maximum concentration on a daily basis and for an extended period of time. More realistically, people would encounter a range of concentrations, including none, because not every chemical was detected in every sample and (2) adults and children are not expected to be visiting the creeks as often as 365 days of the year.
Therefore, even though contamination was detected in Mullet, Trout, and Basin Creeks, adverse health effects are not expected from people engaging in recreational activities in the past, present, or future. For health evaluations concerning exposure at the Herbicide Exposure Unit in other environmental media, please see the Herbicide Contamination and Air Contamination Concerns.
An unnamed pond near the North Gate of Eglin Main Base is in a remote area with limited accessibility (e.g., access roads are not maintained), about 2,000 feet from the nearest non-base resident (Eglin AFB 2001b). A community member was concerned that Herbicide Orange was present in the pond. About 20 years ago, the community member would ride a horse from the stable to the pond and reported seeing a sign that warned of Herbicide Orange contamination. The Air Force has no records of ever placing a sign at this unnamed pond and the sign is no longer present. There are no historical Air Force documents that indicate Herbicide Orange was ever present at this pond (personal communication with Eglin AFB personnel, April 2002).
If Herbicide Orange was present, people would need to have contact with either the surface water or sediment in the pond to be exposed (e.g., either through touching the water or sediment or drinking water from the pond). If people are not being exposed, no harmful health effects can occur. Currently, there is no fence surrounding the pond or preventing access to the pond. A private off-base riding stable in Valparaiso, Florida is about 450 to 600 feet from the unnamed pond. The area between the stable and the pond is currently filled with building rubble, which severely limits access to the pond.
This unnamed pond is not an ideal location for recreational activities (e.g., swimming). Therefore, it is unlikely that anyone actually had contact with potential contamination in the pond, even in the past when people reportedly rode their horses to it. Because access to the pond is currently limited, there is a low chance that anyone is or will be exposed to high levels of contamination for a long time and on a regular basis. Consequently, harmful health effects are not expected to occur.
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