PUBLIC HEALTH ASSESSMENT
PEASE AIR FORCE BASE
PORTSMOUTH, ROCKINGHAM COUNTY, NEW HAMPSHIRE
Pease Air Force Base (Pease AFB) is located in the New Hampshire Seacoast Region between the City of Portsmouth and the towns of Newington and Greenland, New Hampshire. From 1956 until its closure in 1991, the base maintained a combat-ready force for long range bombardment operations. Due to environmental contamination of soils and groundwater, Pease AFB was placed on the National Priorities List in 1990.
Under the Air Force's Installation Restoration Program, environmental investigations began in 1983. Currently, the base is in the later stages of cleanup, with Records of Decision completed for contaminated areas and all required remedial actions complete or ongoing. Base property is being transferred to the Pease Development Authority for reuse as a civilian commercial center.
The New Hampshire Department of Health and Human Services (NHDHHS) and the U.S. Agency for Toxic Substances and Disease Registry (ATSDR) have reviewed available environmental information related to contaminated areas on the base and identified several exposure situations requiring more detailed evaluation. The situations involved past and current exposures to chemical contamination in surface water, groundwater, sediments, and fish tissue. NHDHHS also reviewed soil gas data to evaluate the possibility that groundwater contamination beneath the base might affect the indoor air quality of some buildings on the site.
Based on this review, all of the exposure situations were categorized as either no apparent public health hazard or no public health hazard due to chemical exposures at levels that are unlikely to result in adverse health effects, or limited access to chemical contamination that prevents exposure.
Exposure Situations With No Apparent Public Health Hazard
Consumption of contaminated groundwater
Past use and disposal of chemicals on the base have resulted in groundwater contamination. In 1977, trichloroethylene (TCE) was detected in the base water supply aquifers. In 1994, nitrate concentrations in the base drinking water supply were elevated. Both contaminants were at levels exceeding current drinking water standards. Although levels were above regulatory drinking water standards, people exposed to these contaminants in drinking water are unlikely to experience any adverse health effects because of the low levels of chemicals present and short duration of exposure. The contamination sources have been identified and measures taken to reduce the contaminant levels. Drinking water on base is regularly monitored, and currently meets all standards for drinking water.
Recreational Use of Peverly and Bass Ponds
Chemical contamination was found in sediments, surface waters, and fish in Peverly and Bass Ponds. These ponds were used for fishing and swimming while the base was active. Exposures to mercury, polychlorinated biphenyls (PCBs), and the pesticide DDT by past recreational users who swam, waded, and fished were below levels where adverse health effects are likely. Currently, the area is within the Great Bay National Wildlife Refuge and access is restricted.
Exposure Situations with No Public Health Hazard
Installation Restoration Program sites
The 49 Installation Restoration Program (IRP) sites, flight line, and petroleum underground storage tanks pose no public health hazard. There is no evidence of past or current exposures to hazardous substances at these sites and future exposures are not likely to occur. Institutional controls such as restrictions on use of groundwater and limitations on construction in contaminated areas are in place to prevent exposure. Contamination is under remediation, and the migration of contaminants in the environment is being monitored and is not expected to result in future exposures for workers and visitors at Pease AFB.
Potential Exposure Situations
Potential Building Indoor Air Contamination
It is theoretically possible that some contaminants in the groundwater beneath Pease AFB may evaporate, migrate upwards through the soil gas, and eventually impact the indoor air quality of buildings in the area. While there are no data on indoor air quality at Pease AFB, limited data on soil gas do not suggest that current indoor air quality problems would be expected. However, to guard against potential future exposures, this potential pathway should be kept in mind during the redevelopment of the base.
A. Site Description and History
Pease Air Force Base (Pease AFB) occupies 4,255 acres in Rockingham County within the City of Portsmouth and the towns of Newington and Greenland, New Hampshire (Figure 1). With the onset of World War II, the U.S. Navy used an airport at the current base location. The U.S. Air Force assumed control in 1951, and the base was completed in 1956. The mission of the base was to maintain a combat-ready force capable of long-range bombardment operations. During the Air Force's long history at Pease AFB, the handling and disposal of hazardous materials has resulted in contamination of soils, sediments, surface water, and groundwater. Pease AFB was placed on the National Priorities List (NPL) of Superfund sites in 1990 and closed as an active base in 1991 (USAF 1990).
The Air Force began an environmental clean-up program at Pease in 1983. The program is operated under Air Force's Installation Restoration Program (IRP), Superfund, and state regulatory requirements. The IRP is a Department of Defense program established to identify locations of past hazardous substance releases and minimize associated hazards to human health and the environment. To carry out IRP objectives at Pease AFB, two Preliminary Assessment/Site Investigations were conducted to determine whether sites posed risks warranting further study. At several sites that posed risks, interim remedial actions were taken that were designed to quickly reduce the threat to human health. For sites that required additional study, Remedial Investigations were carried out to assess the nature and extent of the contamination and to identify potential risks. In conjunction, Feasibility Studies were performed to examine and evaluate remedial clean-up alternatives. A proposed plan was then drafted identifying the preferred clean-up strategies. The U.S. Environmental Protection Agency (USEPA), the State of New Hampshire, and the Air Force decided upon the clean-up strategies and formalized them in Records of Decision (RODs). The remedial actions (control measures and remedies) were then designed, constructed, and put into place.
To facilitate organization of remedial actions at Pease, the area has been divided into eight zones containing several IRP sites and the flight line (Figure 2). To date, all contaminated sites have been characterized, RODs have been signed for all the zones that required remedy selections for the various IRP sites within them, and necessary remedial actions have been completed or are in place and operating. All zones are under routine long-term sampling plans to monitor contamination levels and the effectiveness of control measures.
Areas of Special Notice and Groundwater Management Zones have been established within the base perimeter, and outside the property boundary into Newington town property to restrict installation of wells and excavation of contaminated soils (Figure 3). These institutional controls are designed to prevent future exposures to chemical contamination that is still in the process of being cleaned up and, in some cases, being allowed to breakdown naturally.
In 1990, an Environmental Impact Statement was performed to document environmental conditions at base closure (USAF 1990). In 1995, an Environmental Baseline Survey was performed to assess and inventory base environmental conditions and to investigate the presence of contamination in base buildings before property transfer (Earth Tech 1995). Findings of Suitability to Lease that document environmental conditions and define whether designated parcels of property can be transferred have been completed. To date, all parcels have been leased to the Pease Development Authority and U.S. Department of the Interior under a long-term lease agreement with the Air Force. The base is currently supporting several agencies and commercial operations and is continuing to develop as a commercial tradeport.
An evaluation of demographic statistics from the 1990 census indicates that 13,337 people live within one mile of Pease AFB. Of that total, 1,739 are children under 6 years, 1,138 are adults 65 years and older, and 3,350 are women of childbearing age (Figure 4). Commercial and residential areas bound the base to the northeast, southeast, and south. In October 1989, 3,465 military personnel were assigned to the base, accompanied by 4,746 dependents. The Air Force estimates 537 civilian employees were employed on base at that time (USAF 1990). From 1970 to 1990, an average of 3,000 personnel and their families were assigned to the base at any one time. Before 1970, the base supported a maximum of 5,000 personnel (USAF 1994).
The U.S. Agency for Toxic Substances and Disease Registry (ATSDR) has conducted site visits and met with base personnel on two occasions. The first visit occurred in 1991 following base closure when ATSDR staff toured the base to collect information needed to develop a Public Health Assessment. In response to a request from the Air Force, an assessment of contamination at Building 227 (Site 39) was performed to evaluate the potential for exposure for current and future workers inside a building that was proposed for property transfer to civilian use as a hangar. It was determined that contamination did not pose a risk, but that groundwater from the area not be used and that a health and safety plan for site construction activities be developed under the site lease (Little 1991).
Staff from the New Hampshire Department of Health and Human Services (NHDHHS) and ATSDR met with representatives from USEPA, the New Hampshire Department of Environmental Services (NHDES), and the Air Force during a second site visit performed in December 1997. The visit was conducted to collect and review available site-specific information, to visually inspect each contaminated site and other areas containing hazardous materials, and to identify whether and how people could come into contact with site contamination. Information was obtained regarding the nature and extent of site contamination and what actions had been taken to reduce exposure. Proximity of the sites to populated areas was evaluated along with types of human activities that could lead to exposures to site contaminants.
D. Quality Assurance and Quality Control (QA/QC)
In preparing this document, NHDHHS relied on the information provided in referenced documents and contacts. It is assumed that adequate QA/QC measures were followed with regard to sampling, laboratory analysis and data reporting as detailed in the analytical reports. Validity of the analyses and conclusions drawn in this document are determined by the availability and reliability of the referenced information.
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