PUBLIC HEALTH ASSESSMENT
USA DEFENSE DEPOT MEMPHIS
MEMPHIS, SHELBY COUNTY, TENNESSEE
The Defense Depot Memphis Tennessee (DDMT) was a fenced and guarded military supply, storage, and maintenance facility on the south side of Memphis from 1942 to 1997. The population within a mile of the site is nearly all African-American.
The Agency for Toxic Substances and Disease Registry (ATSDR) determines that the DDMT National Priorities List (NPL) site is no apparent public health hazard from 1989 to the present for persons living around DDMT. ATSDR also concludes that the public health hazard of DDMT was indeterminate before 1989 because contaminant data for this time period are lacking. An increased chance of cancer could have existed for workers with daily exposure to polycyclic aromatic hydrocarbon (PAH)-contaminated soil at 3 locations on the DDMT Main Facility.
Surface water and sediment, and ground water are the principal ways DDMT contaminants can move, are moving, or have moved off the site. For surface water and sediment, human contact with water from DDMT is almost entirely restricted to 3 surface-water drainages. These drainages are the Tarrent Branch that flows off the west side of the Main Facility, the ditches that flow from Dunn Field into or by the Rozelle neighborhood, and the drainage that flows south from the southeast corner of the Main Facility. Between 500 and 3,000 individuals could potentially have contact with water in these 3 drainages. The current levels of the site-contaminants in those drainages do not represent a public health hazard. Data are lacking on whether DDMT contaminants in these 3 drainages could have been a past public health hazard. For ground water, movement of site contaminants off site is primarily restricted to the northwest corner of Dunn Field. No one drinks this contaminated ground water.
Short-term exposure to air-borne contaminants from DDMT has occurred. Long-term exposure probably has not occurred.
Food chain (e.g., rabbits, squirrels, fish, plants) and offsite soil do not appear to be viable pathways for long-term exposure.
This document fulfills ATSDR's commitment to DDMT area residents to reevaluate the 1995 DDMT Public Health Assessment (PHA). ATSDR has also fulfilled commitments to review cancer data for the DDMT area and establish the Greater Memphis Environmental Justice Work Group. Enhancement of the environmental medicine capabilities of DDMT area health care providers or clinics, another ATSDR commitment, is currently being planned. A specific health education program will be designed once this PHA is released. ATSDR commits to reviewing additional environmental data if requested.
This public health assessment (PHA) was written to evaluate new sampling data for the Defense Depot - Memphis, Tennessee (DDMT) National Priorities List (NPL) site, review existing data on the Dunn Field portion of DDMT, and respond to health issues and concerns raised by residents living near the site. This PHA is the fulfilment of a commitment made in 1997 by the Agency for Toxic Substances and Disease Registry (ATSDR) to revisit the DDMT PHA issued in 1995 (1,2).
ATSDR very much needs and values any comments, concerns, or clarifications that the various
DDMT stakeholders might have on this public health assessment. These stakeholders include
area residents; and the various local, state, and federal agencies and elected officials involved
with DDMT. These groups may have knowledge that could lead ATSDR to change or revise
one or more of the conclusions in this document. No individual or organization outside of
ATSDR has seen, reviewed, or approved this document before this release for public comment.
The Defense Depot Memphis Tennessee is located on the south side of Memphis (Figure 1). It was a fenced and guarded military supply, storage, and maintenance facility from 1942 to 1997 (3). Commodities distributed from DDMT included food, clothing, medical supplies, electronic equipment, petroleum products, construction materials, and industrial chemicals.
Most depot operations occurred on the main facility (3). Food, clothing, medical supplies, and similar items were stored in 28 large brick buildings called utilities. Construction materials, drums of chemicals, and such were kept in open-sided metal sheds. A variety of vehicles and trailers were stored in open areas (Figure 2). Facilities were also available for painting, sand blasting, vehicle maintenance, medical waste disposal, plus a cafeteria, base exchange, medical clinic, gas station, and an administrative building. In addition, there were a swimming pool, nine-hole golf course, two ponds, and eight units of base housing. Most of the 26 miles of railroad tracks and 28 miles of hard surfaced roads, were or are on the main facility (4). The rail tracks ran north onto Dunn Field where they merged into one track, then joined the main rail line (3).
Chemical warfare-related materials were stored at DDMT from 1942 to 1961 (5). From 1942 - 1945, substantial amounts of chemical warfare-related hazardous materials were stored. Most of this storage took place in the buildings near the northwest corner of the Depot (Figure 2). These hazardous materials include non-persistent agents like tear gas, phosphorus grenades, and incendiary bombs; and flammable, corrosive, or toxic liquids and solids.
Inert (non-hazardous) materials like gas masks, respirators, decontamination apparatus, and related materials were also stored. Persistent chemical warfare agents (e.g., mustard agent, nerve gas) were not stored at DDMT.
The amount of chemical warfare-related hazardous materials dropped rapidly after World War II (5). The main mission of the Chemical Section at DDMT became the servicing of gas masks; testing of flame throwers; and storage of decontamination materials, Chemical Agent Identification Sets (CAIS), and gas mask parts.
The Dunn Field portion of DDMT was used for many years to dispose of chemical and solid wastes from depot operations [Figure 3] (3). It was also used to store national stockpiles of bauxite and fluorspar (non-toxic minerals used to make chemical agents), and was the location for a firing range used by the security staff.
While mustard agent was not stored at DDMT, there is one reported incident of it being disposed of at DDMT. In 1946, German mustard bombs, being transported by rail through the Memphis area, were found to be leaking (5). The train was brought to the DDMT Main Facility where the leaking bombs were unloaded and the train decontaminated. Locations where this was done are identified on Figure 2. The bombs were taken to Dunn Field where an attempt to detoxify the mustard agent was made by shooting holes in the bombs, then draining the agent into a vat of bleach. The bleach and the bomb casings were then buried on Dunn Field (Figure 3).
Burial of chemicals on Dunn Field was done without the impermeable (i.e, liquids can't flow through) liners and caps now required (3). This resulted in extensive contamination of the Fluvial Aquifer, both on and off the northwest corner of Dunn Field, with trichloroethylene, tetrachloroethylene, and related compounds, and metals like arsenic and lead. The Fluvial Aquifer starts about 30-40 feet below the surface and continues down another 100 feet or so. Flow of the contaminated groundwater is towards the Allen Well Field, which is used by the City of Memphis as a secondary source of drinking water.
This proximity of contaminated ground water to drinking water wells was a major reason why the U.S. Environmental Protection Agency (EPA) placed DDMT on the National Priorities List (NPL) in 1992 (6). It was also placed on the NPL because of a surface water migration pathway. This pathway included a lake on the facility (Lake Danielson) which had fish and sediment contaminated with chlordane, DDT, and polychlorinated biphenyls (PCBs).
The process to clean up hazardous materials spilled, leaked, or disposed of at DDMT began in 1980 under the Department of Defense's Installation Restoration Program [IRP] (7). However, reports on the handling and impact of hazardous materials at DDMT go back to the 1960s (3).
These reports include industrial hygiene (workplace) and environmental investigations of chemical and radioactive substances. In addition to the IRP, environmental investigations address NPL-related issues, the closure of DDMT, and its restoration as a site for light industry, recreation, and other activities (8-10). These environmental investigations will be described in the next section of this PHA (Current Conditions of Site).
The demographic characteristics of the population within a mile of DDMT are displayed on Figure 4. Nearly 97% of residents in this area are African-American.1 About 12.5% of this population is 65 years or older which is the same percentage as for the United States, but is greater than the 8.1% for African-Americans in Shelby County. About 12% of the people living within a mile of DDMT are six years old or younger, while for African-Americans in Shelby County this age group is about 13.5% of the population. Women of child-bearing age (15-44 years old) make up 24% of both the population within a mile of DDMT and of African-Americans in Shelby County.
The possible impact of DDMT on groundwater and the process to clean up the site became public information through a series of newspaper articles, public meetings, the Restoration Advisory Board (RAB), and regular mail-outs of information (11-32). Memphis residents were made aware, through a 1991 newspaper article, that one of the city well fields was contaminated and that DDMT was a possible source (11). Two articles in 1992 revealed that the shallow groundwater under Dunn Field was contaminated (12,13). The listing of DDMT on the National Priorities List (NPL) was also described in a 1992 article (14). Eight articles in 1993 - 1995 covered clean-up activities and public meetings (15-22). Extensive sampling of DDMT, concerns of the DDMT-Concerned Citizens Committee (CCC), a 1998 hazardous waste incident, and cleanup of the mustard agent were among the topics of the articles from 1996 to 1999 (23-30).
Since the site went on the NPL list in 1992, DDMT has made efforts to communicate with people around the facility through public meetings, establishment of a RAB, and informational mailings to the community (16,31). For example, health concerns were identified in May 1993 at a meeting with about 150 residents of the Orchid Homes community, and at an August 1993 meeting with about 60 area residents.
At Department of Defense sites, local citizens and elected officials; facility staff; and local, state and federal environmental agency staff participate in Restoration Advisory Boards (RAB). The DDMT RAB was formed in July 1994 and holds monthly meetings (32). The RAB receives briefings on and discusses activities related to site cleanup and restoration.
DDMT regularly distributes a newsletter, notices of meetings, and similar information to about 5,000 individuals.2 They also announce activities through press releases.
Persons living around DDMT have high levels of concern about this site as indicated in a survey conducted recently by the Memphis-Shelby County Health Department (33). Results of this survey revealed that over 90% of survey respondents desired more information on the potential for exposure to and health effects from DDMT contaminants, the results of environmental sampling of DDMT, and how the Depot would be cleaned up and restored. A similar percentage of survey participants indicated that additional off-site environmental sampling should be done.
ATSDR's first major activity at DDMT was in 1992 when a preliminary evaluation was made to identify whether immediate action was needed at the site to protect public health (34). It was concluded that no immediate action was necessary.
In 1995, ATSDR evaluated the possible public health impact of the site in the DDMT Public Health Assessment (1). The soil, groundwater, surface water, air, and food chain exposure pathways were analyzed using information on site activities, the geology around DDMT, and limited environmental sampling. All these environmental pathways were classified as "no apparent public health hazard". In a 1996 letter to a concerned citizen, ATSDR indicated that this meant that, "Contamination at the depot does not pose a health concern to people living on or near the depot, and it did not pose a health hazard in the past." (35).
In 1996, ATSDR evaluated sediment sampling that was conducted after the release of the 1995 PHA (36). Of the 18 samples taken from the drainage ditches that emanate from the facility, nine were taken in or near the Rozelle area west of Dunn Field. They were analyzed for a wide variety of chemicals including volatile and semi-volatile chemicals, metals, pesticides, polychlorinated biphenyls (PCBs), and dioxins. Low levels of contaminants were found at most locations. The conclusion of the evaluation was that, "Although numerous contaminants were detected, they were not of the type and amounts that would pose a public health hazard..." (36). Results of this sediment sampling will be discussed in more detail on page 15.
In 1996, a group of area residents (DDMT-Concerned Citizens Committee [CCC]) contacted ATSDR with their concerns about the site and the DDMT PHA (37). This led to a commitment by ATSDR in 1997 to: 1) revisit the 1995 public health assessment, 2) review cancer incidence data gathered by the State of Tennessee in 1996, 3) review a plan for ongoing medical surveillance of residents, and 4) work with the DDMT-CCC, the Health and Human Services (HHS) Region IV Office, Memphis Health Center, the Congress of National Black Churches, local affiliates, and Shelby County/State of Tennessee to pursue provision of primary care services that have an environmental health focus in the reported area (2).
Since these commitments were made, ATSDR personnel have made numerous trips to Memphis (38-50). During these trips, staff identified additional community health concerns; toured the site; represented ATSDR at the monthly RAB meeting; identified possible sampling locations; and met with DDMT-area residents and staff from DDMT, EPA, Tennessee Department of Environmental Conservation (TDEC), the Memphis-Shelby County Health Department (MSCHD), and Meharry Medical College.
ATSDR helped organize the Greater Memphis Environmental Justice Work Group. This group has met on February 27 and October 17, 1998. The working group is addressing environmental and health concerns of Memphis area residents with a focus on African-Americans and the DDMT area (43).
Objectives of the Greater Memphis Environmental Justice Work Group are being met through the activities of several sub-groups (43). Members of these subgroups include area residents and representatives of MSCHD, TDEC, ATSDR, EPA and DDMT. The health education and promotion sub-group is identifying the specific health messages that will be communicated to Memphis Depot area residents. The health concerns sub-group has reviewed and commented on the cancer incidence study being done by ATSDR and the Tennessee Department of Health. The health care sub-group is insuring that appropriate health care is provided to area residents possibly affected by environmental contaminants. In the October 1998 meeting of the Greater Memphis Environmental Justice Work Group, the site characterization sub-group described how contamination at the Memphis Depot has and is being identified. There are also subgroups for other environmental hazards and the public health assessment.
ATSDR has had considerable interaction with DDMT-area residents besides the Greater Memphis Environmental Justice Work Group, including 3 public availability sessions and 2 public meetings to identify community health concerns and solicit input from area residents on ATSDR activities (38,39,46,51,52). ATSDR staff have made 4 tours of the DDMT area with members of DDMT-CCC or other area residents to identify possible exposure pathways and gain general knowledge about DDMT and the surrounding community (38,41,42). All these activities were done with the cooperation and foreknowledge of DDMT-CCC.
DDMT-area residents and staff from ATSDR, EPA, and MSCHD meet regularly as the health education and promotion sub-group of the Greater Memphis Environmental Justice Work Group to identify the specific health messages for DDMT-area residents (53-56). Members of this group receive detailed briefings of ATSDR activities and make comments and suggestions.