COAKLEY LANDFILL

Community Update On Coakley Landfill From USEPA and NHDES December 5, 2018

1. Treatment systems have been installed by the Coakley Landfill Group (CLG) at two private wells that
exceeded the recently revised NHDES ambient groundwater quality standard (AGQS) for 1,4 dioxane
(adjusted downward from 3 parts‐per‐billion to 0.32 ppb on September 1, 2018). One private well is a
residence just northwest of the landfill on Breakfast Hill Road, and the other is the Breakfast Hill Golf Club.
The treatment systems are operating and have been approved by NHDES. NHDES is requiring that the
CLG expand the Site GMZ to incorporate these two properties. It is important to note that the
concentration of 1,4‐dioxane in these two private wells has maintained relatively consistent levels since
sampling began in 2012.

2. Samples from packer testing of newly installed bedrock boreholes have been analyzed for PFAS, 1,4
dioxane and VOCs, and preliminary data has been provided to the agencies. Validated data is anticipated
to be submitted next week. The CLG continues to pursue access to 7 historic bedrock boreholes located
north, south and east of the landfill for surveying and sampling and has gained verbal agreement to access
3 of the wells.

3. Wet weather storm water runoff samples were collected from landfill cover retention basins and
discharge culverts, underdrain discharge locations and landfill seep locations on October 27. These
samples were collected in accordance with a work plan that CLG prepared and EPA reviewed and
approved, to further investigate the extent of PFAS contamination potentially associated with landfill
cover material. Samples are being analyzed and results will be provided once the data is reported by the
lab. Additional sampling at these locations will be conducted in the spring.

4. Representatives from the United States Geological Survey (USGS) visited the site on October 24 to
become more familiar with site features and to discuss the scope of work for modeling localized, sitespecific
groundwater flow characteristics (model). Based on the findings of this visit, the USGS prepared a
revised scope of work which has been reviewed by EPA. An interagency agreement for the development
of this model is being finalized. Development of this model is scheduled to take about 12 months,
although adjustments to the schedule may be needed based on the collection of data from the ongoing
bedrock investigation that will be used in the model.

5. The CLG has conducted its fall monitoring round, including sampling of groundwater monitoring wells,
surface water, leachate and off‐site wells. Samples are being analyzed by the lab and results should be
available within two weeks.