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MIAMI COUNTY
TROY
Congressional District # 08
EAST TROY CONTAMINATED AQUIFER
EPA ID# OHSFN0507962Last Updated: September, 2009
Site Description
The East Troy Contaminated Aquifer site is located in the eastern portion of the City of Troy, Miami County, Ohio along the western bank of the Great Miami River. The site boundaries and all contamination source(s) have not yet been identified. The upcoming remedial investigation and feasibility study (RI/FS) will provide this information. Existing data demonstrates that the site includes at least a twelve square block area where volatile organic compounds (VOCs) have been identified in groundwater, soils, and indoor air space of residential, public and commercial properties. Across the Great Miami River, within 0.25 miles of the site is the city of Troy's East Well Field which serves as a drinking water supply for the city of Troy. Since 1988, the VOCs, cis-1, 2-dichloroethane (cis-1, 2-DCE) and trichloroethene (TCE), have been consistently detected in samples taken from the East Well Field.
The site was proposed on the National Prorities List (NPL) in September 2007, and one year later in September 2008, the site was finalized on the NPL.
Site Responsibility
U.S. EPA is the lead agency. Ohio EPA is providing support to U.S. EPA.
Threats and Contaminants
Contaminants identified in ground water include tetrachloroethene (PCE), TCE, cis-1, 2-DCE, and vinyl chloride. Elevated levels of PCE in groundwater and soil gas were detected in a three block residential area between Franklin Street and Main Street. PCE concentrations as high as 801 parts per billion (ppb) in groundwater and 58 ppb in soil gas were found in samples collected from residential yards along Franklin Street. The EPA has documented a total of sixteen residential locations and one elementary school with indoor air PCE, and/or TCE vapor concentrations exceeding the Agency for Toxic Substances and Disease Registry (ATSDR) health screening level of 1.2 ppb or 0.4 ppb, respectively. The EPA installed vapor abatement systems at sixteen homes and one elementary school as part of a 2007 U.S. EPA removal action.
Although VOCs detected in samples from the East Well Field are below federal Maximum Contaminant Levels (MCLs), contaminated ground water (plume) is migrating towards the well field, which provides drinking water to approximately 28,000 people in the city of Troy. Additionally, vapor intrusion of VOCs into indoor air is a concern for residents living in the area.
Cleanup Progress
From July through April 2007, the EPA conducted a removal assessment to determine the extent of vapor intrusion contamination and to mitigate levels of VOCs in indoor air that exceed health screening levels established by the ATSDR and Ohio Department of Health. The EPA collected sub-slab and indoor air samples from a total of eighty-five locations, which included seventy-eight residences, two churches, four schools and the Troy Police Station. The assessment confirmed that sixteen residences and one elementary school had indoor air PCE, and/or TCE vapor concentrations exceeding the ATSDR health screening level of 1.2 ppb or 0.4 ppb, respectively. As a result, the EPA installed vapor abatement systems at sixteen homes and one elementary school as part of a 2007 EPA removal action.
The EPA initiated negotiations with potentially responsible parties in 2008 for performance of the RI/FS. Negotiations did not result in a settlement and therefore, EPA initiated the investigation in June 2009. Field work will begin in the fall.
Community Involvement
The EPA conducted a public meeting in Troy, Ohio, on October 25, 2006, and invited residents to sign-up for sub-slab and indoor air sampling. In addition, the EPA sent letters in December 2006, to 400 residences in the plume area, requesting access to conduct sub-slab and indoor air sampling. Approximately 60 additional residents agreed to provide access for the sub-slab and indoor air sampling. The EPA also kept residents informed throughout the vapor investigation via fact sheets, EPA's web site, and newspaper releases. The Agency will hold additional information sessions and meetings as work on the RI/FS progresses.