OSWER/OSRTI

Washington, DC 20460

NATIONAL PRIORITIES LIST (NPL)

[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.]

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 http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.

***Proposed Site*** March 2012

WEST TROY CONTAMINATED AQUIFER Troy, Ohio

Miami County

 Site Location:

The West Troy Contaminated Aquifer is located in the City of Troy. Troy operates two well fields located along a 1.25 

mile segment of the Great Miami River. Troy’s West Well Field is comprised of four wells located on the east side of 

the Great Miami River on parklands bordering the river. 

 Site History:

Since 1986, volatile organic compounds (VOCs) have been detected in a production well which is part of the Troy’s 

West Well Field. The Ohio EPA conducted several investigations beginning in the early 1990s; however, a definitive 

source for VOC contamination in the West Well Field has not been identified. 

 Site Contamination/Contaminants:

Tetrachloroethene (PCE) has been detected in untreated water from Troy’s West Well Field public drinking water 

production well (PW) 12 at concentrations which exceed the federal drinking water maximum contaminant level 

(MCL). Trichloroethene (TCE), cis-1,2-dichloroethene (DCE) and 1,1,1-trichloroethane (TCA) have also been 

detected at lower concentrations. Low levels of DCE were also recently detected in PW-3W in Troy’s West Well 

Field.

 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 four water wells in the West Well Field. VOC contamination in the East Well Field is being addressed under 

the East Troy Contaminated Aquifer National Priorities List (NPL) site. A separate ground water plume is moving 

toward Troy’s West Well Field. The municipal system supplies water to approximately 28,000 people. 

 Response Activities (to date):

The EPA and the Ohio EPA have conducted assessment work for the ground water plume and source areas but have 

not identified the source of VOC contamination. Further investigation is needed to identify the source of VOC 

contamination and define the precise extent of the ground water plume.

 Need for NPL Listing:

Applicable federal and state cleanup programs were evaluated to determine the best program to clean up this site. The 

State of Ohio referred the site to the EPA because a long-term comprehensive solution is needed to protect the City of 

Troy’s municipal wells. The Superfund NPL program provides the best approach to investigate and address all of the 

contamination sources and associated plumes at this site to protect human health and the environment. The EPA 

received a letter of support for placing this site on the NPL from the state governor on September 15, 2011.