PUBLIC HEALTH ASSESSMENT
LANGLEY AIR FORCE BASE
NASA LANGLEY RESEARCH CENTER
HAMPTON, YORK COUNTY, VIRGINIA
Langley Air Force Base (Langley AFB) and the National Aeronautics and Space Administration Langley Research Center (NASA LaRC) are located adjacent to each other on a small coastal basin of the Back River, a tidal estuary of the Chesapeake Bay. While the facilities are separate entities, they were listed jointly on the National Priorities List in 1994, based on the potential for identified contaminants to migrate to area surface waters. The two facilities are conducting separate remedial investigation and cleanup activities.
The Agency for Toxic Substances and Disease Registry (ATSDR) visited the sites in 1994 and 1997. During the 1994 visit, several potential public health concerns were raised: 1) the potential for contaminants to migrate to fish and shellfish (which might be ingested by local residents) in the adjoining estuary, 2) surface soil contamination at a former playground at Langley AFB Site OT-06, 3) surface soil contamination and physical hazards at Langley AFB Sites OT-25 and FT-41, where children or youths might trespass, 4) the use of Langley AFB Site LF-12 for storing fill material, and 5) lead-contaminated soil in the housing areas at Langley AFB. ATSDR made recommendations for several of these sites. During the 1997 visit, ATSDR identified one additional potential concern at NASA LaRC Site 4, an open storage site where surface soil has not been characterized.
Since ATSDR's initial visit, several concerns have been addressed and site contamination has been more fully characterized. Fish and shellfish in Tabbs Creek were sampled and found to be contaminated with pesticides, polychlorinated biphenyls, polychlorinated terphenyls, dioxins, furans, and metals. Due to biological contamination that was discovered in the 1980s, fishing is currently prohibited in Tabbs Creek. On the basis of available data, ATSDR concludes that the past occasional ingestion of fish and shellfish from Tabbs Creek is unlikely to pose a health hazard for either adults or children. ATSDR recommends that the creek continue to be posted for no fishing to protect public health in the future. Fish and shellfish from the Back River are currently being studied; ATSDR will review the findings when they are available and revise the conclusions of this public health assessment, if necessary.
ATSDR evaluated the potential for adverse health effects to occur to children playing at the former playground at Langley AFB Site OT-06, and for children or youths trespassing at Langley AFB Sites OT-25 and FT-41. On the basis of available data, ATSDR concludes that exposure to contaminants in soil at these sites is not likely to pose a health hazard. Physical hazards at Langley AFB Site OT-25 have been removed and therefore no longer pose a health hazard. ATSDR recommends that access to Langley AFB FT-41, which contains physical hazards, be more fully restricted.
Langley AFB Landfill 12 is no longer used as a storage area for fill material and is no longer a
public health concern. Langley AFB has not sampled soil in residential housing areas, as was
recommended by ATSDR in 1994. ATSDR continues to recommend that the surface soil in on-base residential areas be sampled for lead and, if necessary, undergo remediation. ATSDR also
recommends that soil at NASA LaRC Site 4 be characterized.
Langley Air Force Base (Langley AFB) and the National Aeronautics and Space Administration Langley Research Center (NASA LaRC) are located adjacent to each other in the heavily populated Hampton Roads area of southeastern Virginia, 100 miles south of Washington, DC (Figure 1). The facilities are situated on the small coastal basin of the Back River, a tidal estuary of the Chesapeake Bay. Langley AFB and NASA LaRC are located in York County and bordered to the north, east, and south by the Back River, and to the south by the city of Hampton. The city of Poquoson lies across the northwest branch of the Back River. The city of Newport News is southwest of the two facilities.
Langley AFB and NASA LaRC are situated on the former plantation of George Wythe, one of the signers of the Declaration of Independence (NASA LaRC, 1996). In 1917, the U.S. War Department purchased the land and designated it Langley Field. Langley Field was built as an experimental airfield and aircraft proving ground for joint use by the U.S. Army and the National Advisory Committee for Aeronautics (NACA). Important advances were made at Langley Field during World War I: studies of bomb trajectories, development of bomb sights, turn and bank indicators, and construction of an atmospheric wind tunnel.
Langley Field played a minor role in the American war effort during World War I, but became increasingly active in the years prior to World War II (Radian, 1996). At the end of World War II, the Army's portion of Langley Field was given a training mission and, in 1946, was selected as the permanent home of the Tactical Air Command. This part of Langley Field was designated Langley AFB in 1948. In 1992, Langley AFB was transferred to the Air Combat Command and is currently the home base for the First Fighter Wing. Langley AFB is the oldest continuously active Air Force base in the United States. The primary mission of Langley AFB is to maintain the capability for rapid global deployment and air superiority for the U.S. or allied armed forces (Langley AFB, 1997).
Langley AFB occupies 3,152 acres and is bounded by the city of Hampton on the south, NASA LaRC on the west, and the northwest and southwest branches of the Back River to the north, south, and east (Figures 1 and 2). In addition, Langley AFB supports the 284-acre Bethel Manor Off-Base Housing Area.
On the NACA side of Langley Field, aeronautical research expanded to include aerospace activities. NASA succeeded NACA in 1958. The facility was designated Langley Research Center. NASA now functions as a separate federal agency from the U.S. Air Force, owns its own property, and controls a separate installation adjacent to the northwest portion of Langley AFB. NASA LaRC has evolved into one of the world's leading aeronautical research laboratories; approximately 80 percent of the world's commercial aircraft bear some mark of the work done at NASA LaRC. The primary mission of NASA LaRC is research and development of advanced technologies for aircraft and spacecraft. Specific studies focus on instrumentation, materials fatigue, acoustics, aerodynamics, and guidance control (NASA LaRC, 1996).
NASA LaRC occupies approximately 810 acres of U.S. government-owned land (Figures 1 and 2). The approximately 340 facilities that make up NASA LaRC are split between the West and East Areas, with the majority (90 percent) in the West Area. The West Area is bordered by Brick Kiln Creek on the north, Route 172 on the west, and Langley AFB to the south and east. Tabbs Creek lies between a portion of the eastern boundary of the West Area of NASA LaRC and the northwestern border of Langley AFB. The East Area of NASA LaRC is located within the Langley AFB property along the southwest branch of the Back River.
Both Langley AFB and NASA LaRC are restricted areas. The perimeters are fenced, and access to either facility is gained through staffed entrance gates. Land use in the vicinity of Langley AFB and NASA LaRC is mainly residential, with some commercial and industrial activity.
The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), also known as Superfund, established a series of programs to investigate and remediate releases of contaminants from hazardous waste sites. As part of the Superfund process, an installation restoration program (IRP) was implemented at Langley AFB and NASA LaRC, and preliminary assessments and site inspections were performed during the 1980s to identify potentially contaminated sites. These activities were performed separately at the two facilities.
At the conclusion of these activities, the U.S. Environmental Protection Agency (EPA) assigned the facilities a score using its Hazard Ranking System. If a site receives a score of 28.5 or higher (on a scale of 100), it is placed on the National Priorities List (NPL). After scoring, Langley AFB and NASA LaRC were listed jointly as an NPL site in May 1994. Potential sources of contamination included a series of landfills owned and operated by the Air Force, and storm sewer systems throughout both facilities. The Air Force and NASA are currently conducting separate remedial investigation and cleanup activities.
Wastes generated at the two facilities include: waste oils, solvents, paint wastes, pesticide containers and rinse waters, photographic wastes, scrap materials, used batteries, and printed circuit board plating wastes (EPA, 1993). The facilities' hydraulic systems, electrical equipment, compressors, and casting operations used polychlorinated biphenyls (PCBs) and polychlorinated terphenyls (PCTs). Storm sewers, storm sewer outfalls, sumps, and three drainage systems, all of which are subject to storm and tidal influences, may have been contaminated by releases of PCBs, lubricating oils, hydraulic fluids, pesticides, and heavy metals such as mercury from the facilities. The storm sewer system drains to the Back River and Tabbs Creek, which is a tributary of the Back River; these surface water bodies are contaminated with PCBs and PCTs (EPA, 1993).
As part of the Superfund process, the Agency for Toxic Substances and Disease Registry (ATSDR) visited Langley AFB and NASA LaRC, met with their personnel and toured the sites in 1994 and in 1997.
Langley AFB and NASA LaRC are located on the lower York-James Peninsula of York County, Virginia. The topography is very flat and shows little or no relief. Most of the land lies between five and eight feet above mean sea level (Radian, 1996). The principal geomorphic feature in the county is the Hampton Flat, where the surface dips gently eastward at about 1 foot per mile. Drainage is poor throughout the area and salt and freshwater marshes are common along the major streams flowing into the Chesapeake Bay (Foster Wheeler, 1996).
The Atlantic Coastal Plain's physiographic province consists of an eastward-thickening sedimentary wedge composed of consolidated gravels, sands, silts, and clays, with variable amounts of marine fossils. Langley AFB and NASA LaRC are underlain by approximately 2,000 feet of layered, mostly unconsolidated sedimentary deposits (Foster Wheeler, 1996; Radian, 1996).
There are three aquifers within the coastal plain sediments beneath Langley AFB and NASA LaRC: the Shallow Water Table Aquifer, the Upper Artesian Aquifer System, and the Principal Artesian Aquifer System, all of which are suspected to contain water of moderate to poor quality due to high salinity and total dissolved solids (Langley AFB, 1997). None of the aquifers are used as a source of drinking water at Langley AFB or NASA LaRC. There are no plans for future use of the groundwater as a drinking water source at either of the facilities. Individual homeowners in the area may have groundwater wells that have been used for watering lawns and washing cars (Radian, 1996). Because groundwater generally moves toward the east and the Back River, groundwater contamination at Langley AFB and NASA LaRC is not expected to affect these areas, which are located upgradient to the west.
The Shallow Water Table Aquifer, which ranges in depth from five to 100 feet below land surface, does provide an important source of drinking water farther to the west of Langley AFB and NASA LaRC in King Williams, Charles City, New Kent, James City, and western York Counties. Furthermore, there are areas in Newport News and Hampton where domestic groundwater is obtained from wells that probably draw from the Shallow Water Table Aquifer (Radian, 1996). These areas are located upgradient to the west of any potential contamination from Langley AFB and NASA LaRC.
The water supply for Langley AFB is obtained from surface water sources, primarily the Big Bethel Reservoir, which is owned by the federal government and operated by Fort Monroe, a nearby U.S. Army base. During dry periods or when equipment at the reservoir is undergoing maintenance, the City of Newport News Waterworks supplements the water supply (Langley AFB, 1997). All potable water used at the NASA LaRC is provided by the City of Newport News Waterworks and it remains connected to the Big Bethel Reservoir as a backup. Water service for Hampton and Poquoson is provided by Newport News Waterworks (Radian, 1994).
Transport of dissolved contaminants is very slow due to the low hydraulic conductivity and the low hydraulic gradient of the groundwater. Tidal effects also retard flow, but to a limited extent. Past experience at Langley AFB has shown that the potential transport of dissolved contaminants initially occurs radially away from the source and, over extended periods of time, toward the east and the Back River (Radian, 1997d).
Local recharge to the shallow groundwater system is by precipitation. The aquifer is highly dissected by shallow streams, rivers, marshes, and inlets. Most of the water in the aquifer flows for short distances before discharging to these local surface water bodies (Foster Wheeler, 1996).
Brick Kiln Creek, Tabbs Creek, and several other small creeks drain the Hampton Flat area (NASA LaRC, 1996). Brick Kiln Creek is a tide-influenced creek on the north border of NASA LaRC which flows east into the northwest branch of the Back River. Tabbs Creek, which lies between and drains most of the West Area of LaRC and part of Langley AFB, flows in a northerly direction to join the northwest branch of the Back River. The southwest and northwest branches of the Back River converge east of Langley AFB and NASA LaRC and form a tidal estuary of the Chesapeake Bay. The Chesapeake Bay is located to the east of Langley AFB and NASA LaRC.
Many local residents use the Chesapeake Bay system for fishing, crabbing, and oystering for business and recreational purposes. The Chesapeake Bay and the estuaries associated with it are known for their seafood harvest. The York-James Peninsula and surrounding areas are a vital part of the commercial industry of the Chesapeake Bay region.
Identified natural resources in the area include the Chesapeake Bay and the Plum Tree Island Wildlife Refuge. The Chesapeake Bay is the largest estuary in the United States, with more than 2,000 different marine animals and plants identified within its reaches. The Plum Tree Island Wildlife Refuge, the largest saline marsh in the lower Chesapeake Bay, is located in an area northwest of Langley AFB and NASA LaRC outside the city of Poquoson. The Refuge provides habitats for a variety of water birds, including herons, egrets, and osprey (Foster Wheeler, 1996).
A total of 18,962 people live within a 1-mile radius of Langley AFB and NASA LaRC (Figure 3). Approximately 20 percent of the population is Black, and other races constitute another 4 percent. There are 2,182 children aged 6 years old or younger living within 1 mile of the sites.
More than 10,000 people work at Langley AFB (EPA, 1993). There is a total of 720 airmen living in base dorms and approximately 334 officers or noncommissioned officers in base housing units. There are also 664 dependents living in the base housing units (ATSDR, 1998).
NASA LaRC employs 3,000 civil service employees, primarily engineers and technicians, and 2,200 contractors (NASA LaRC, 1996). There are no residential areas at NASA LaRC.
Hampton borders Langley AFB to the south and east and has a large residential population employed by either the service industries or the federal government. In 1990, the population of Hampton was 133,793. At that time, 58 percent of the population was Caucasian, 39 percent was African-American, and 3 percent was Asian-American, Native American, and other (NASA LaRC, 1996).
Poquoson lies to the north of Langley AFB and NASA LaRC across the northwest branch of the Back River. Poquoson is a residential community with a substantial seafood processing and packaging industry. Poquoson is located on the Poquoson River, which empties into the Chesapeake Bay north of the Back River. In 1990, the population of Poquoson was 11,005, of which 97 percent was Caucasian (NASA LaRC, 1996).
Residential areas of York County lie to the west of Langley AFB and NASA LaRC. In 1990, York County had a population of 42,434, of which 81 percent was Caucasian (NASA LaRC, 1996).
ATSDR relied on the information provided in the referenced documents. The environmental data for Langley AFB presented in the public health assessment are from the draft IRP site inspection and screen risk assessment report for 33 IRP sites (Radian, 1996); the final remedial investigation and baseline human health risk assessment for Site OT-06 (Radian, 1997d; Radian, 1997e); the site summary document for DP-09 (Radian, 1997a); the site closeout document for SS-23 (Radian, 1997b); the site closeout document for OT-40 (Radian 1997c); the draft baseline risk assessment for Site SS-61 (ERM Program Management Company, 1996); the final preliminary assessment report for the Dirigible Area of Concern (Radian, 1998); the draft report for a site investigation, the review draft site investigation report, and the final site investigation report for storm sewer outfalls (Law, 1990; Law, 1991; Law, 1992); the final work plan and the first quarter report of field monitoring and remedial activities for various fuel leaks (IT, 1997; IT, 1998); and the management action plan for various sites throughout the base (Air Force, 1993). The environmental data for NASA LaRC presented in the public health assessment are from the draft final expanded site investigation report for the Pyrotechnics Area (Ebasco, 1995); the draft remedial investigation and the draft feasibility study for the Construction Debris Landfill (Foster Wheeler, 1997c; Foster Wheeler, 1997d); the draft final focused feasibility study report for the Stratton Substation Site (Foster Wheeler, 1997a); the summary report of the site assessment and the draft proposed plan for remedial action for the Area E Warehouse Site (Ebasco, 1990; EPA, 1997); the final data summary and status report and the final engineering assessment for PCB and PCT contamination in storm sewers (Ebasco, 1991; Ebasco, 1993); the final remedial investigation and the final feasibility study for Tabbs Creek (Foster Wheeler, 1996; Foster Wheeler, 1997b); and the revised draft final NPL facility management plan for various sites at NASA LaRC (Ebasco, 1996). ATSDR assumes that adequate quality assurance and control measures were taken during chain of custody, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn in this document are determined by the availability and reliability of the information.