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Plans outline groundwater contamination alternatives at two Massachusetts Military Reservation sites
A 30-day public comment period, ending Aug. 16, began for two “Remedy Selection Plans,” which outline the proposed alternatives for addressing groundwater contamination at two sites on the Massachusetts Military Reservation (MMR). There was also a public information meeting on July 24 on these topics. The plans have been developed to explain the site and present information so the public has clear information on all the alternatives. The Remedy Selection Plans also provide information on the U.S. Environmental Protection Agency’s (EPA) preferred alternative.
The first Remedy Selection Plan is an addendum to the Decision Document for the Demolition Area 1 (Demo 1) site located on the Camp Edwards portion of MMR. The area was used from the mid 1970s until 1997 for training and disposal of munitions, fireworks, explosives and other items. Investigations identified royal demolition explosive (RDX), other explosives and perchlorate in both the Demo 1 groundwater and source area. In 2006 EPA selected a comprehensive remedy for the Demo 1 groundwater plume. The remedy was expected to achieve cleanup levels for RDX and perchlorate by 2018. Further site investigation efforts detected perchlorate across Route 28 as far as County Road in Pocasset. An extraction well was installed on the base boundary and began operating in June 2011. To further aid in the cleanup of the Demo 1 groundwater plume, EPA is proposing Alternative 4A, which is outlined in the Remedy Selection Plan. Alternative 4A would continue to use the current system, optimized, with one off-base extraction well west of Lily Pond, in the Pocasset area of Bourne, as the preferred cleanup alternative for the site. The Remedy Selection Plan, available on EPA’s MMR website, explains the other cleanup alternatives considered for the site and presents why Alternative 4A was selected by EPA as the preferred alternative.
The second Remedy Selection Plan is for the cleanup of groundwater contamination at the J-2 Range in the southeastern portion of Camp Edwards. The J-2 Range is located adjacent to and partially within the impact area. Based on sampling data collected from the site, it was determined that there were several different sources of groundwater contamination. For groundwater investigation and analysis purpose, the J-2 Range has been divided into two sub-areas, the northern plume area and the eastern plume area. The division between these two areas is based on the different source areas for each plume and their distinctly different migration patterns. The chemicals found in the groundwater (RDX and perchlorate) are associated with the use and disposal of military munitions and fireworks. Several response actions have been taken to date to remove many of the groundwater contamination sources. However, soil sampling and clearing of unexploded ordnance is necessary to confirm that any additional sources have been removed. The Upper Cape Cod Water Supply COOP wells are located down gradient. EPA is proposing Alternative 4 - focused extraction with three wells, monitored natural attenuation and land use controls - as the preferred alternative for the J-2 Range northern and eastern groundwater plumes. This alternative optimizes the extraction, treatment and reinfiltration systems that were installed in 2006 in the northern plume area, and in 2008 in the eastern plume area. The Remedy Selection Plan explains the cleanup alternatives considered for both groundwater plumes and why Alternative 4 is preferred by EPA.
The Army National Guard’s Impact Area Groundwater Study Program’s (IAGWSP) investigations and cleanup at Demo 1 and the J-2 Range have been conducted under the oversight of EPA and the Massachusetts Department of Environmental Protection (MassDEP), under the authority of EPA’s Safe Drinking Water Act Administrative Orders and in consideration of the substantive cleanup standards of the Massachusetts Contingency Plan.
The findings are summarized in documents on EPA’s MMR website, which provides comment instructions for both Remedy Selection Plans. After the comment period ends, EPA will consider the public comments, consult with MassDEP and issue a Decision Document providing the details of the actions selected for the sites. With the Decision Document, EPA will include a Responsiveness Summary that provides responses to comments received during the public comment period. MassDEP will issue its official position in a comment letter after the public comment period has ended.