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Site Type: Long Term/National Priorities List (NPL)  |
SOMERSWORTH SANITARY LANDFILL |
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| Somersworth, New Hampshire |
Strafford County
| Street Address: | BLACKWATER RD |
| Zip Code: | 03878 |
Congressional
District(s): |
01 |
| EPA ID #: | NHD980520225 |
| Site ID #: | 0101128 |
| Site Aliases: |
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| Site Responsibility: | Federal, State, Potentially Responsible Parties |
| NPL LISTING HISTORY |
| Proposed Date | 12/30/1982 |
| Final Date | 09/08/1983 |
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Site Description
The 26-acre Somersworth Sanitary Landfill is located approximately 1 mile southwest of downtown Somersworth. The City of Somersworth operated a disposal site on the property from the mid-1930s until 1981. Originally, the City burned residential, commercial, and industrial wastes at the site. In 1958, the dump was converted to a landfill. Unknown quantities of sludges, solvents, acids, dyes, metals, laboratory or pharmaceutical wastes, and potash were disposed of at the site. In 1981, four groundwater monitoring wells installed as part of site closure activities indicated that volatile organic compounds (VOCs) and inorganic contaminants were present. The landfill is located in a predominantly residential area of Somersworth. Forest Glade Park, which was reclaimed as a recreational park in 1978, sits atop the easternmost 10 acres of the site. An apartment building for senior citizens, a fire station, and a National Guard Armory abut the property to the east, and an elementary school is located approximately 2,300 feet northeast. Approximately 11,000 people live in Somersworth. The former Somersworth Municipal Supply Well #3 was located approximately 2,300 feet from the landfill. This well was closed and dismantled because of historically high levels of iron and manganese, which were unrelated to the landfill. Previously, the well supplied approximately 10 percent of the City's total water supply and was used during peak periods. Most of the residences in the area obtain drinking water from the Somersworth municipal supply system; however, there are at least seven private wells in the area. Peter's Marsh Brook, located adjacent to the western edge of the landfill, is a tributary of Tate's Brook, which, in turn, is a tributary of the Salmon Falls River. Both the City of Somersworth and the City of Berwick, Maine withdraw water from the river for their drinking water supplies. Water intakes are located approximately 1 mile from the landfill.
Threats and Contaminants
The groundwater is contaminated with VOCs and inorganic chemicals. Sediments were found to contain low levels of arsenic, chromium, and lead. Peter's Marsh Brook and Tate's Brook have been shown to contain VOCs and metals, including arsenic and mercury unrelated to the landfill. Peter's Marsh Brook is considered to be the primary receptor of groundwater contamination. If private water supply wells were installed or reopened in this area or near Peter's Marsh Brook, long-term exposure to contaminated drinking water would pose potential health risks. However, the City has passed a zoning ordinance which prohibits use of the contaminated ground water.
Cleanup Approach
Rather than implement a traditional landfill closure remedy, an innovative remedy, involving a chemical treatment wall or permeable reactive barrier, is being used to clean ground water.
Response Action Status
| Entire Site | The parties potentially responsible for the site contamination conducted an investigation into the nature and extent of site contamination. In the summer of 1994, remedies were selected in a Record of Decision (ROD) to clean up the groundwater, which included using an innovative permeable reactive barrier that destroys the VOCs as the groundwater flows through the wall, with a final cap to be determined after cleanup. The ROD also specifies a contingent remedy, if the permeable reactive barrier is ineffective, which calls for a standard cap and a pump and treat system. Design of the remedy began in early 1996. Construction of the permeable reactive barrier was completed in the Fall of 2000. A permeable cover, which allows precipitation to flush contaminants from the landfill through the treatment wall was completed in the summer of 2001. |
| Enforcement Highlights | The EPA entered into a Consent Agreement in 1989, requiring the potentially responsible parties to investigate the nature and extent of site contamination. The settling parties also agreed to pay past State and Federal costs for the site, and future oversight costs. EPA and 20 parties entered into a Consent Decree in late 1995 in which the settling parties agreed to design, construct, and operate the 1994 selected remedy. |
Environmental Progress
Following listing of the Somersworth Sanitary Landfill site on the NPL, the EPA determined that the site contamination did not pose an immediate threat to public health or the environment while cleanup activities are on-going. The passage of the local zoning ordinance prohibiting ground water use in the area further protects the public health. The potential for explosive levels of landfill gas to collect in nearby structures is expected to be eliminated by the recent installation of a gas collection trench.
Current Site Status
In January 2000, the Town of Somersworth adopted institutional controls at the site to prevent the use of contaminated ground water. Ground water monitoring is continuing during ground water treatment using the permeable reactive wall. Soil gas investigations, completed in early October of 2002, are expected to help determine the extent to which the landfill surface can be used for recreational purposes. Construction of the gas collection trench was completed by the end of December, 2003. Soil gas monitoring results have shown the trench to be effective in preventing landfill gas migration towards residences.
Site Photos
 
Summer of 2000: Placement of iron filings into trench around landfill to August 2001: Hydroseeding permeable landfill cover.
create permeable reactive barrier to treat groundwater.
Links to Other Site Information
Newsletters & Press Releases:
Federal Register Notices:
Administrative Records:
Reports and Studies:
Decision Documents:
Other Links:
Site Repositories
Somersworth Public Library, 27 Main Street, Somersworth, NH 03878
EPA New England Records Center, One Congress Street, Boston, MA 02114 (617) 918-1440
Contacts
| EPA Remedial Project Manager: | Michael Jasinski |
| Site Responsibilities: | Section Chief, NH/RI Superfund |
| Address: | |
| Phone #: | (617) 918-1352 |
| E-Mail Address: | jasinski.mike@epa.gov |
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| EPA Community Involvement Coordinator: | Angela Bonarrigo |
| Address: | |
| Phone #: | (617) 918-1034 |
| E-Mail Address: | bonarrigo.angela@epa.gov |
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| State Agency Contact: | Andrew Hoffman |
| Address: | New Hampshire Department of Environmental Services
PO Box 95
Concord, NH 03302-0095 |
| Phone #: | (603) 271-6778 |
| E-Mail Address: | ahoffman@des.state.nh.us |
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