Solid Progress Made for Data Collection to Support EPA’s Groundwater NTCRA
Fall and winter RI/FS activities included the installation and sampling of 25 groundwater monitoring wells to further delineate the 1,4-dioxane plume associated with the site. de maximis and its subcontractor, Geosyntec, met with representatives of EPA, MassDEP and the community groups in December 2015 to discuss the investigation results and next steps. Three additional monitoring wells were installed in January 2016, as shown on the figures illustrating the locations of and monitoring data for the investigations (NMI GW Figures).
Since January, the technical team has been working with EPA, MassDEP and the Acton Water District to design and implement a shutdown test of the Assabet 1A and 1B production wells. This test is planned to start the week of March 14. The resulting data will help to define the capture zone of the Assabet wells, which will assist in the selection of an effective location to install and test a pumping well. That test data will be a key component for the design of the system that will be installed to cut off the flow of contamination from NMI. In summary, solid progress has been made to collect the data necessary to design the Groundwater Non-Time-Critical Removal Action (NTCRA) selected by EPA in September 2015 as part of the necessary remediation for the site.
Installation of monitoring well 32, September 2015.