Superfund Information Systems: Site Profile

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The former Pease Air Force Base is located in Portsmouth and Newington, New Hampshire. The facility officially closed in April 1991 under the Defense Base Realignment and Closure Act of 1988. Wastes generated by the U.S. Air Force when the facility was active have contaminated soil, groundwater, surface water and sediment across the former base. The Air Force has completed cleanup work, and continues to monitor progress until cleanup goals are met.

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What Has Been Done to Clean Up the Site?

The site is being addressed through state and potentially responsible party (PRP) actions.

During early site contamination studies, the Air Force removed solvent-containing drums from the Landfill 5 area, removed contaminated soil and installed pilot groundwater extraction and treatment plants at several buildings. This early work removed and controlled immediate threats, pending further studies. Cleanup of Landfill 5 finished in 1996. Cleanup activities included consolidating buried landfill debris in contact with groundwater in dry areas of the landfill and landfill capping.

The Air Force finished contamination studies at the Fire Department Training Area-2 in 1994. Cleanup included extracting jet fuel floating on the groundwater table, vapor extraction and air sparging of subsurface soils, and pumping and treating groundwater to control the migration of site contamination. Active treatment of site soils is largely completed with the exception of some small areas within the site. The Air Force is evaluating the use of amendments that are injected into the subsurface to destroy residual soil contamination. Groundwater treatment will continue at the site and focus on the migration and treatment of the PFAS contamination that has been discovered in groundwater monitoring and private drinking water wells.

Cleanup of Building 222 involved removing petroleum- and solvent-contaminated soils for off-base treatment and disposal. This work finished in 1995.

Cleanup of Buildings 113/119 relied on a combination of containment walls and groundwater extraction wells to prevent contaminated groundwater from migrating from Site 32 (Building 113). In 2014, the Air Force excavated and disposed off-site 2,800 cubic yards of deep contaminated soil that represented a continuing source of groundwater contamination at the site. Groundwater extraction and treatment has been deactivated to assess post-soil removal sucess in improving groundwater quality. The Air Force is also evaluating insitu enhanced bioremediation in addressing residual groundwater contamination. Restrictions limit groundwater use and groundwater monitoring is ongoing. Contaminated soil with associated with historical operations at Building 119 (Site 36) were excavated and disposed of off-site in 1996.

Cleanup of the Old Jet Engine Test Stand included air sparging of soil and groundwater below the water table and vapor extraction of soils above the water table. Soil cleanup is finished. Restrictions limit groundwater use and groundwater monitoring is ongoing.

Cleanup plans for areas known as Zone 1, 2, 3 and 4 were finalized in the summer of 1995. The remedies for all four zones include restrictions on groundwater use and long-term groundwater monitoring.

The remedy for Zone 1 included no further action for five potential areas of contamination. The remedy also called for allowing natural processes to reduce low levels of volatile organic compounds (VOCs) in groundwater. The contamination came from Landfill 5. Capping of Landfill 5 combined with natural processes is expected to restore groundwater quality to drinking water standards.

The remedy for Zone 2 included treatment of contaminated subsurface soil by air sparging and vapor extraction to treat petroleum- and solvent-contaminated soils at Burn Area #1. Air sparging and soil vapor extraction soil treatment finished in 2003. The Air Force is evaluating the effectiveness of insitu bioremediation in treating residual site groundwater contamination.

The remedy for Zone 3 included excavation and off-base disposal of metals and sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) from two ditches. It also involved excavation and off-base disposal of metals and PAH-contaminated soil near three buildings. Groundwater contaminated with volatile organic compounds (VOCs) is extracted at two Zone 3 sites and treated at an on-base groundwater treatment plant. In 2003, the Air Force updated the Zone 3 cleanup plan to include contingency wellhead treatment capabilities for the nearby Haven water supply well. This backup treatment system was designed and constructed to treat VOC-contaminated groundwater, should this contamination threaten the water quality at the Haven water supply well.

The remedy for Zone 4 included excavating soils from Landfill 6 and consolidating the material into Landfill 5 before its capping, as well as restoring the Landfill 6 area to wetland and upland habitat.
The Air Force completed studies of Zone 5 in the fall of 1994 and determined that no further actions were necessary.

Cleanup of four surface water drainage-ways included excavation and off-base disposal of sediments contaminated with PAHs, metals and pesticides in McIntyre Brook and Paul’s Brook. No more work was necessary at Flagstone Brook and Lower Newfields Ditch.

At former Building 22 (Site 49), preliminary field investigations identified soil and groundwater contaminated by VOCs. As part of preliminary investigations in 1997, part of the building was demolished and contaminated soil beneath it was excavated and disposed of off base. In 2000, the Air Force built a permeable reactive barrier to treat contaminated groundwater. In 2014, the remedy was updated to include the implementation of insitu enhanced bioremediation to speed up the pace of groundwater cleanup of the site. Restrictions limit groundwater use and groundwater monitoring is ongoing.

Solvents containing VOCs were used at Building 234 in Site 73 and reportedly disposed of on site. An innovative technology demonstration here in August 1999 consisted of the installation of a barrier to intercept and destroy VOC-contaminated groundwater. In 2012, the Air Force further modified the cleanup plan to include the injection of a water-and-emulsified-vegetable-oil solution into groundwater to speed up the biodegradation of remaining groundwater contamination. Microorganisms were also added to the solution to accelerate groundwater cleanup.

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What Is the Current Site Status?

A Federal Facility Agreement finalized in April 1991 established the responsibilities of the Air Force, the New Hampshire Department of Environmental Services (NHDES) and EPA for cleanup at the 4,365-acre site. The partners completed 11 Records of Decisions describing site cleanup plans between 1993 and 1997. All construction work required under the Federal Facility Agreement has since finished. Remedy optimization, operation and maintenance, and long-term monitoring work are ongoing until all cleanup goals have been met.

Direct contact threats on the former base have been eliminated through numerous Air Force cleanup actions.

EPA issued an Administrative Order under the Safe Drinking Water Act requiring the design and construction of two treatment systems to address groundwater contamination that continues to threaten drinking water supplies while also expediting the investigation and cleanup of the emerging contaminants PFOA and PFOS in the aquifer.  Construction of one treatment system is ongoing and scheduled for completion in January 2018 with startup in 2018.  Construction of the second treatment system is expected to start in spring 2018.

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Activity and Use Limitations

At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.

For more background, see Institutional Controls.

Institutional controls are required for this site.
This site requires ICs because a decision document, such as a Record of Decision, has documented some level of contamination and/or remedy component at the site that would restrict use of the site. These ICs are required to help ensure the site is used in an appropriate way and that activities at the site do not damage the cleanup components. These ICs will remain in place for as long as the contamination and/or cleanup components stay on site. The matrix below is a general summary of the restrictions at this site at the date of this report. The information in this matrix is a general description of the restrictions at the site only. The site contacts should be consulted if there are questions on the ICs for this site.
The following IC Instruments provide media-specific use restrictions that have been implemented by EPA for protecting human health, the environment and remedial engineering on this site. Instruments are documents used by EPA or other organizations to implement the use restrictions at a site. To know about other media-specific use restrictions that are planned but not implemented at this site, please contact the Regional Office using the Site Contact listed above. Note that where multiple entries occur, it will impact more than one pathway.
Click here for IC Instruments implemented for this site. 

ICs are generally defined as administrative and legal tools that do not involve construction or physically changing the site. Common examples of ICs include site use and excavation restrictions put in place through State and local authorities like zoning, permits and easements. ICs are normally used when waste is left onsite and when there is a limit to the activities that can safely take place at the site (i.e., the site cannot support unlimited use and unrestricted exposure) and/or when cleanup components of the remedy remains onsite (e.g., landfill caps, pumping equipment or pipelines). Effective ICs help ensure that these sites can be returned to safe and beneficial use.
Disclaimer: This information is being provided by EPA as an informational tool to further assist the public in determining the types of restrictions that may be in place at National Priorities List sites being addressed by EPA under the Superfund program. In addition to the areas addressed by the institutional controls identified on this web site there may be other areas on the property that require restrictions on use of the property that are not captured in this EPA database. States and other entities may have implemented laws or restrictions applicable to this site. The information provided herein does not replace a title search or meet "All Appropriate Inquiry" requirements. U.S. EPA encourages users to review the Site files to obtain information regarding remedy components, containment systems and the land use for which cleanup standards were selected for these sites. More information and links can be found in the Institutional Control instrument collection of document, above, and the EPA regional offices may also be contacted.

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