US Army Corps of Engineers, New England District

Overview:

• Under the Avatar HTRW contract with the New England District of USACE (CENAE), Avatar is performing an RI/FS for CENAE under its FUDS program for the LO-58 Site.
• The Site was acquired from the Town of Caribou in 1955 by the U.S. Department of Defense (DOD) for the construction of a Nike missile launching facility.
• This Site was one of four Nike Ajax sites placed around Loring Air Force Base for the protection of the United States Air Force Strategic Air Command B-52 Stratofortresses as well as northeastern approaches to the United States. These sites remained operational until the LO-58 Site was deactivated by the DOD in 1966.

Description:

The primary objectives for the LO-58 Site are to

• 1) characterize the nature and extent of contamination
• 2) evaluate the environmental fate and transport of Site-related contamination
• 3) assess the potential risks to human health and the environment posed by contamination at the Site
• 4) use this information in the FS to support the evaluation and development of potential remedial alternatives for the Site
• 5) produce Decision Documents.

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The scope of work also includes Proposed Plans, public meetings, field investigations, and regulatory agency negotiations. Project plans included a Quality Assurance Project Plan (QAPP), a RI/FS Workplan, an Accident Prevention Plan (APP), and a Field Sampling Plan (FSP). Field investigations included geoprobe drilling, groundwater well installation, and collection of soil, groundwater, surface water, sediment, and air samples. A strategy of sampling subslab and indoor air at an on-site occupied building (Adult Learning Center) was developed which minimized disruption to ongoing activities. All field samples were sent to and analyzed by a DOD accredited laboratory under the DoD Environmental Laboratory Accreditation Program (ELAP) program.

Following field investigations to determine the extent to which soil, groundwater, sediment, surface water, soil gas and indoor air have been impacted by releases of petroleum hydrocarbons and chlorinated solvents related to the historic operations of the LO-58 Nike Site, CERCLA- and MEDEP-compliant Human Health and Screening Level Ecological Risk Assessments (RAs) were performed. The results of the RAs indicated the need for the development of groundwater and indoor air remedial alternatives.

Five groundwater and four vapor intrusion alternatives were identified to address the contaminated bedrock groundwater and indoor air at the Site. A detailed analysis of the alternatives was performed according to the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) and CERCLA, to provide information necessary to facilitate the selection of a remedy. A Life Cycle Cost Analysis was conducted for each proposed alternative. Based on the results of the RI/FS and comments from project stakeholders, including the general public, a Decision Document will be prepared for approval by the USACE, MEDEP, and other stakeholders.