The East Troy Contaminated Aquifer is located in the eastern portion of City of Troy along the western bank of the Great Miami River. The contaminated ground water plume is moving primarily northeast toward the Great Miami River.
Two distinct ground water plumes have been detected. The two ground water plumes are contaminated at various levels with volatile organic compounds (VOCs), including cis-1, 2-dichloroethene (cis-1, 2-DCE), tetrachloroethene (PCE), and trichloroethene (TCE). The State of Ohio currently has an agreement in place to address a source area for one of the plumes. There is no source control on the second plume. The State and EPA are working to find a comprehensive solution to address both plumes, any additional source areas, and potential issues related to vapor intrusion.
The contaminants of concern in the two ground water plumes are PCE, TCE, and cis-1, 2-DCE. PCE and TCE are typically used as a dry cleaner, paint remover, parts cleaner, engine cleaner, etc.
Potential Impacts on Surrounding Community/Environment:
The City of Troy obtains drinking water from two municipal well fields. There are five water wells in the East Well Field and five water wells in the West Well Field. Troy does not have a blended water system. The wells are currently below Maximum Contaminant Levels (MCLs), but the plume is migrating towards the well fields. The municipal system supplies water to approximately 28,000 people. In addition, vapor intrusion between the two ground water plumes is a potential concern for residents living in the area.
Response Activities (to date):
EPA and the State have conducted assessment work at the two ground water plumes and at some limited source areas. The State currently has an agreement with a potential responsible party to operate a source control system at their property, which addresses contamination from one of the ground water plumes. EPA is currently conducting a removal assessment to determine if vapor intrusion is a concern.