EPA agreement outlines cleanup of New Hampshire landfill
A new consent decree for the Dover Landfill Superfund
site has cleared the way for continued clean up work and better environmental
protection, including groundwater remediation, at the site. The consent
decree is subject to a 30 day public review and comment period.
The Dover Municipal Landfill Superfund Site, located in Dover, New Hampshire,
is a 50-acre uncapped landfill. Ground water beneath the site has been
contaminated with arsenic and organic compounds, and the contamination
extends well beyond the landfill boundaries, north and eastward to the
Cocheco River and south toward the Bellamy Reservoir.
The landfill began operations in 1961 and closed in 1979. While it operated,
Dover Municiple landfill accepted household wastes, as well as wastes
from local industries that included liquid hazardous wastes. These liquid
hazardous wastes consisted of tanning solutions and chlorinated solvents.
The site was placed on the National Priorities List on September 8, 1983.
EPA initially outlined a clean up plan for the site in 1991, which was
the basis of a 1993 consent decree with the “potentially responsible
parties,” all of whom agreed to perform portions of that plan. The 1993
consent decree required the creation of an impermeable cap on top of
the 50-acre landfill, but deferred a decision on a ground water remedy
until further studies were performed.
Due to the many complexities of cleaning up the site, EPA and the New
Hampshire Department of Environmental Services (NHDES) allowed the responsible
parties to consider other remedial options for source control that would
protect the public health and the environment while remaining cost-effective.
Based on several years of studies, EPA issued an amended “Record of Decision”
(ROD) in 2004 that selected a new source control remedy – to capture
high-concentration contaminants in selected hot-spots within the landfill,
and to capture and treat dissolved contaminants in ground water along
the perimeter of the landfill. The high-concentration contaminants within
the landfill will be treated on site. The 2004 Amended Record of Decision
retained the ground water remedy from the 1991 Record of Decision, including
capturing contaminants in the southern plume and discharging the water
to the City’s sewer system for treatment. Currently, there are no exposure
pathways that pose a hazard to the public or environment. Ground water
contamination, however, may pose a threat to public water supplies if
it is allowed to continue unchecked.
Since EPA issued the Amended Record of Decision in 2004, the potentially
responsible parties have been conducting investigations to accelerate
the implementation of the remedy. Portions of the ground water pump and
treatment system south of the landfill began operating in April 2008.
It is expected that the EPA, NHDES and the potentially responsible parties
will continue this collaborative effort to address site contamination
and any potential threat to public water supplies.