The Rouge River and its tributaries flow approximately 570 miles through Wayne, Washtenaw, and Oakland Counties and drains approximately 466 square miles of Southeast Michigan. The Rouge River has four branches (Main, Upper, Middle, and Lower). The Main Branch Rouge River originates in Rochester Hills and flows in a south/southeast direction. The Upper, Middle, and Lower Rouge Rivers originate near West Bloomfield Township, the City of Wixom, and Superior Township. The Upper, Middle, and Lower Rouge River meet with the Main Branch Rouge River near Redford Township, Dearborn Heights, and Dearborn, respectively. From Dearborn, the Main Branch Rouge River flows east/southeast through a heavily industrialized area before entering the Detroit River near Delray.
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) first analyzed per- and polyfluoroalkyl substances (PFAS) in surface water in 2001 when 21 streams, including the Rouge River, were sampled for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). The study found varying levels of PFOA and PFOS in the Rouge River. At that time, there were no water quality standards for these compounds in surface water, however, the concentrations measured in 2001 do not exceed the surface water quality standards for PFOS or PFOA that exist today.
As a part of routine monitoring, EGLE’s Fish Contaminant Monitoring Program collected fish from the Rouge River in October 2019. Fish were collected from the Rouge River downstream of the confluence with the Lower Rouge River and from the Newburgh Lake impoundment of the Middle Branch of the Rouge River. These samples were processed as fillets and analyzed for PFAS as well as other contaminants. Results are discussed below.
Surface water from the river near its confluence with the Detroit River was sampled for PFAS again in November 2019 after the Wyandotte Municipal Services drinking water plant returned an abnormally high detection of PFOS and perfluorohexane sulfonate (PFHxS) in raw and finished water samples in August 2019. PFOS and PFOA concentrations in these surface water samples were below three parts per trillion (ppt). For reference, concentrations of PFOS and PFOA less than two ppt are considered background levels in surface water.
- In 2021, EGLE plans to collect fish from the Lower Rouge River, the main branch of the Rouge River, and the Middle Branch of the Rouge River for PFAS and other contaminant analyses.
- EGLE will use the October 2020 surface water sample data to continue our PFAS source tracking efforts within the watershed in order to identify potential sources.
- Beginning in 2021, Wyandotte Municipal Services drinking water plant and GLWA will be performing compliance monitoring for the seven PFAS compounds with Maximum Contaminant Levels.
- EGLE has planned six months of source water (raw) sampling at all community water supplies in Michigan which utilize surface water as a source. This list includes Wyandotte Municipal Services drinking water plant and GLWA.