The New Hampshire Department of Environmental Services (NHDES) announced this week that it has received draft results for groundwater samples collected at the former Merrimack Town Landfill that showed elevated concentrations of perfluorooctanoic acid (PFOA).
The former Merrimack Town Landfill property consists of two unlined landfills, totaling 25 acres, near the current Merrimack transfer station in the south-central part of the state.
NHDES officials are expanding their efforts to find out how much potentially toxic chemicals, such as PFOAs, ended up in drinking water, from private wells to public water systems.
In response to a request from NHDES, the U.S. Environmental Protection Agency (EPA) collected and analyzed water samples from 10 monitoring wells adjacent to the landfill. These wells were previously installed to monitor the potential impact of the landfill on groundwater. The draft test results, which are being reviewed by the EPA for quality assurance, showed that the groundwater samples contained PFOA at concentrations ranging from “none detected” to 2,200 parts per trillion (ppt); eight of the samples showed concentrations of more than 100 ppt. To further evaluate the extent of the impact, the NHDES said it will begin sampling private residential water supply wells in the vicinity of the landfill.
The NHDES noted that these landfills were operated from the early 1970s to 2003, and received solid waste from households and businesses in and around Merrimack. The landfills were capped with an impermeable membrane in 2004. Groundwater monitoring began in 1987 and continues under a Groundwater Management Permit issued by the NHDES.