|Commerce Street Plume||Williston, Vermont|
The Commerce Street Plume is located within an industrial park on Commerce Street in Williston, Vermont, in Chittenden County. Ground water plumes of volatile organic compounds (VOCs) and metals have been traced to releases from a one-acre property formerly owned by Mitec Systems Corp. (Mitec).
Various manufacturing and electroplating operations have occurred on the property since 1960. Between 1979 and 1984, Mitec discharged an undetermined quantity of plating rinse waters and sludge wastes containing heavy metals and solvents into an unlined lagoon and a septic leachfield. In 1984, monitoring wells detected chromium in ground water downgradient of the lagoon, and in 1985, six nearby residential wells were found to be contaminated with solvents at concentrations exceeding Maximum Contaminant Levels. Indoor air samples collected in residences down gradient from the property showed VOCs at levels posing unacceptable risk to humans. The drinking water wells were subsequently closed and residents were provided with an alternate drinking water supply. Onsite manufacturing ceased in 1986, and the property is currently occupied by a restaurant supply business.
Two source areas have been discovered on site, which are contributing to the ground water plume: plating rinsewater and sludge wastes containing heavy metals and solvents discharged into the unlined lagoon and the leachfield. VOCs (including PCE, TCE, and DCE) and metals (including chromium, cadmium an nickel) have been detected in soil and ground water throughout the property, and TCE and PCE have been detected in nearby drinking water wells at concentrations above health-based standards. In addition, elevated levels of contaminants linked to the property have migrated to nearby streams and wetlands via ground water.
Potential Impacts on Surrounding Community/Environment:
Ground water plumes emanating from the property threaten public and private drinking waters supplies located downgradient from the site. Elevated concentrations of 11 VOCs and 13 metals have been detected in monitoring wells located throughout the industrial park and surrounding residential area. Six heavily-contaminated private drinking water wells were taken out of service by the Vermont Department of Health and residents were provided with an alternated drinking water supply in 1985. One home was fitted with a venting device to address vapor intrusion concerns. Recent studies have documented elevated concentrations of VOCs and metals in wetlands and the unnamed stream which flows into Muddy Brook and ultimately the Winooski River. The unnamed stream is a habitat for two State-designated threatened species and is a State-designated area for protection and maintenance of aquatic life under the Clean Water Act. Muddy Brook and the Winooski River downstream of the property are known fisheries.
Response Activities (to date):
In 1984, the Vermont Agency for Environmental Conservation filed suit against Mitec for alleged contamination and submitted an Administrative Order to Mitec issuing a formal notice of violation and charging them with illegal disposal of hazardous waste. Six residential drinking water supplies affected by the releases were taken out of service in 1985, and residents were provided with an alternate water supply. One home was vented to address vapor intrusion. Recent investigations have further delineated the extent of ground water, soil, and surface water contamination beyond the one-acre former Mitec property.
[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent FR notices.]
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.