Construction activities are underway once more at the 13-acre New Hampshire Plating Company Superfund site, located in Merrimack, N.H.
Over the next year, EPA contractors will excavate and treat between 60,000 and 90,000 cubic yards of contaminated soil from areas of the site. Once excavated, the material will be treated with a process known as chemical fixation that binds metal contaminants preventing them from being available to migrate and contaminate the underlying groundwater. The treated materials will then be backfilled into the excavation areas on site and graded with the rest of the property. A permeable cap will be constructed over the treated soils and the property will be configured and vegetated.
Last fall, EPA contractors cleared approximately seven acres of brush, trees, and overgrowth from the site so that construction vehicles could access the property. In the early spring, EPA oversaw the demolition of a 13,600-ton concrete storage cell, created during an earlier phase of work at the site. The concrete was broken into gravel-sized pieces and stockpiled on site. It will be used in the construction a permeable cap over the site.
In 2001, EPA awarded a grant of $99,000 to the Town of Merrimack, to develop a reuse plan for the site. The reuse plan that the town’s landscape architect developed calls for recreational use of the site.
The 13-acre New Hampshire Plating Superfund site operated as an electroplating facility from 1962 to 1985. Wastewater containing metals, solvents and cyanide used in the electroplating operations was discharged into drainage channels in the former building floor, and flowed into unlined lagoons north of the building. Contaminants from the unlined lagoons impacted on-site wetlands, contaminated surface and subsurface soils, and reached the groundwater.
To date, EPA has spent a total of about $8.5 million at the site to conduct interim cleanup measures, perform comprehensive site investigations and complete remedial design efforts. In addition, as compensation for the loss of wetlands at the site, EPA and NHDES have provided over $1.6 million for the purchase and protection of the 50-acre Greens Pond wetland area in Merrimack and the 38-acre Grassy Pond wetland area in Litchfield, N.H.
Between 1989 and 1994, EPA stabilized contaminated soils and sludge in an on-site storage cell, removed additional soil for off-site disposal, and demolished a former electroplating building (including the foundation, floor slab and underground storage tanks). The site was added to EPA's National Priorities List, commonly known as the Superfund list, in 1992.