Record of Decision System (RODS)
PETOSKEY MUNICIPAL WELL FIELD
|Site Name:||PETOSKEY MUNICIPAL WELL FIELD|
|Address:||200 W LAKE ST|
|City & State:||PETOSKEY MI 49770|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Contaminant:||Dioxins/Dibenzofurans, Inorganics, Metals, PAH, PCBs, Pesticides, VOC|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The Petoskey Municipal Well Field site is located in Petoskey, Michigan. The site includes contaminated source area soils and the groundwater that has been affected by contaminants migrating from the source area. Groundwater contamination has impacted the Ingalls Avenue Municipal Well, which is located on the shore of Lake Michigan and, until late 1997, supplied water to residents of the City of Petoskey.
The Petoskey Manufacturing Company, Inc. (PMC) is a small fabricating operation that was established in 1946 as a die cast manufacturer, continued with painting operations in the late 1960s, and remains in operation today.
In 1981, the Ingalls Well was found to be contaminated with volatile organic compounds (VOCs). In 1982, the U.S. Environmental Protection Agency (U.S. EPA) and the Michigan Department of Environmental Quality (MDEQ) identified PMC as a potentially responsible party for the water supply contamination. In 1982, under the direction of the MDEQ, PMC removed approximately 131 cubic yards of contaminated soil, backfilled the excavation, and capped it with a polymembrane liner. Prior to 1982, trichloroethylene (TCE) concentrations of approximately 50 parts per billion (ppb) were found in the Ingalls Well. Following the removal of the contaminated soil, TCE concentrations in the municipal well decreased to approximately 4.0 ppb and have remained relatively stable.
In July 1983, the PMC site was evaluated using the Hazard Ranking System. The PMC site was subsequently added to the National Priorities List in September 1983.
In 1984, the U.S. EPA negotiated an Administrative Order by Consent with PMC. This Order required PMC to conduct further hydrogeological studies. Work included the installation of four monitoring well clusters, ground water and soil sampling, and ground water flow analysis.
In 1987, PMC signed another Administrative Order by Consent with the U.S. EPA. PMC agreed to conduct a full Remedial Investigation/Feasibility Study (RI/FS) to determine the nature and extent of contamination and investigate appropriate remedial alternatives to address the contamination. PMC started the work plan phase of the Administrative Order, but in 1990 the U.S. EPA relieved PMC of conducting further RI/FS work due to delays in developing the work plan and PMC's questionable financial ability to complete the work required by the Administrative Order. The U.S. EPA entered into a State Cooperative Agreement with the MDEQ in 1990, in which the MDEQ agreed to perform the RI/FS and U.S. EPA agreed to fund the investigation.
While the state-lead RI/FS was ongoing, EPA in 1992 began a focused FS to examine the impact of the PMC contamination at the Ingalls well. The focused FS concluded that current VOC levels at the well were below the Maximum Contaminant Levels (MCLs) promulgated pursuant to the Safe Drinking Water Act. The focused FS also determined that risk levels calculated for present and future scenarios based on current levels of contamination are within the U.S. EPA's acceptable risk range. However, because of the uncertainty associated with future concentrations of VOCs in the Ingalls well, the U.S. EPA in 1993 proposed that an air-stripper be constructed at the Ingalls well to reduce existing levels of VOCs in the well and ensure that the City's water supply is not adversely impacted by the higher levels of VOC contamination that have been found in ground water near the Ingalls well. This action was proposed as an interim measure at the Ingalls well to fully ensure the protection of the City's water supply with regard to PMC site-related contamination.
In June 1995, EPA signed a Record of Decision (ROD) for providing on-line treatment of groundwater at the Ingalls well. Air stripping was identified as the appropriate treatment technology. The State requested that the city's construction of a new drinking water source be considered. EPA agreed to contribute the capital costs ofthe selected remedy to be used by the state to partially defray the city's costs of replacing the Ingalls well. Therefore, EPA's selected remedy of an air-stripper on the Ingalls well was not and will not be implemented. A ROD was issued in September 1998 presenting the intended final response actions at the site.
The selected soil alternative includes the construction and operation of a Soil Vapor Extraction (SVE) system to remove trichloroethylene (TCE) from deep unsaturated soils. In addition, the excavation of the top 5 feet of soil from the property will remove organics and inorganics that pose a direct contact threat for future residents (if the property is developed) and pose a threat of continued leaching to groundwater. After operation of the SVE system, approximately 15 cubic yards of contaminated soil would be removed to meet Michigan Generic Soil Direct Contact Criteria. In addition, approximately 2,050 cubic yards of contaminated soil would be removed to remove the potential source of groundwater contamination and to meet Michigan Department of Environmental Quality (MDEQ) soil criteria for protection of groundwater and surface water quality.
A deed restriction will be placed on the Petoskey Manufacturing Company (PMC) property identifying the landowner's "due care" responsibilities in accordance with provisions of Michigan Part 201 if the current structure is partially or totally removed.
Once the PMC soils have been addressed by SVE and excavation, the residual contaminated groundwater will be allowed to naturally attenuate with the remaining contamination diluting, dispersing, and discharging into Lake Michigan. Groundwater contaminant concentrations are expected to decrease dramatically once the source area soils are addressed. An aggressive monitoring program will be implemented to establish a baseline of contaminant concentrations in groundwater. Routine monitoring will be implemented to track contaminant levels, consistent with anticipated decreases from natural attenuation. Additional deed restrictions preventing exposure to the contaminated groundwater will be implemented for the PMC property and all properties where the contaminated groundwater plume exists and migrates. This remedy also assumes that the Ingalls municipal well will continue to remain unused as a drinking water source.
Estimated Capital Costs: $185,800
Estimated Annual O&M Costs: $49,500 for years 1 to 3, $8,800 for years 4 to 30
Estimated Present Worth Costs: $250,700
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