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NPL Site Narrative for Mohawk Tannery

MOHAWK TANNERY
Nashua, New Hampshire

Federal Register Notice:  May 11, 2000 (PDF) (7 pp, 265K, About PDF)

The former Mohawk Tannery facility (a.k.a. Granite State Leathers) is located on a 30-acre parcel in Nashua, Hillsborough County, New Hampshire. The site is being proposed to the NPL on the basis that sludge discharged from the Mohawk Tannery facility containing elevated levels of arsenic, cadmium, chromium, lead, pentachlorophenol, chlorobenzene, and trichloroethylene has been documented to be below the water table and in direct contact with ground water, which is used for drinking water. Wastewater containing chromium also has been discharged directly into the Nashua River via an outfall pipe from a tank on the Mohawk Tannery property. Both the Nashua River and the Merrimack River are fished extensively and wetlands are located along both rivers.

The facility produced tanned hides for leather between 1924 and 1984 and is currently inactive. The property is bordered by the Nashua River to the west and by residences to the southeast and east. There are gaps and breaks in the chain link fence surrounding the northern portion of the property and New Hampshire Department of Environmental Protection personnel have observed children riding bikes along an on-site dirt trail between the river and two on-site surface impoundments (Areas I and II). There are no barriers to access on the southern part of the property. In August 1999, an auto repair business was observed operating on-site in violation of local zoning ordinances.

The former tannery produced both alkaline and acid wastestreams. Due to incomplete records, little is known about the tannery's waste treatment and management practices prior to the 1960s. From the 1960s until the completion of an on-site treatment facility in 1981, the alkaline wastestream was transported to a screen building for removal of solids and then to Area I and Area II (the surface impoundments) for long-term sedimentation. The liquid fraction was discharged directly to the Nashua River and the sludge in the surface impoundments was periodically dredged and buried on-site in Area III. The acid wastestream passed through a series of five settling basins (Area IV) and was then discharged to the Nashua River via an open channel. During the construction of the new treatment facility, the dredged sludge was buried in Areas IV and V on-site.

After the completion of the new on-site treatment facility in 1981, the alkaline and acid wastestreams were combined and transported to a primary clarifier, then to Area I for sedimentation, and then to a secondary clarifier. Part of the sludge from the secondary clarifier was pumped back to the primary clarifier and part back to Area I. The liquid waste from the secondary clarifier was discharged to the Nashua River under a 1978 National Pollution Discharge Elimination System (NPDES) permit. Sludge remains on-site in the secondary clarifier tank and buried in Areas II, III, IV, V, and VI. Area I is open and currently contains liquid and sludge.

A population of approximately 5,024 persons receive drinking water from ground water wells within a 4-mile radius of the site. A drinking water intake located 14.3 miles downstream of the effluent outfall on the Merrimack River serves a population of over 100,000 persons. Analytical data document the presence of elevated levels of metals in ground water and in sediments in the Nashua River. Both the Nashua River and the Merrimack River are contiguous to wetlands and are characterized as fisheries.

For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.

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