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Ecorse River Watershed

Ecorse River Watershed

The Ecorse River watershed drains 43 square miles of Wayne County and is a tributary to the Detroit River.  The watershed is divided in to three sub-watersheds:

  1. The Main Branch of the Ecorse River is 17 miles long and is in the northern portion of the watershed.
  2. The LeBlanc Drain, an enclosed storm sewer, runs 9.6 miles and drains the central portion of the watershed.
  3. The South Branch of the Ecorse River, which includes the Sexton-Kilfoil Drain, extends 13 miles in the southern portion of the watershed.  

The river was first sampled for per- and polyfluoroalkyl substances (PFAS) in November 2019 near its confluence with the Detroit River 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.

Elevated PFOS concentrations were found in the Ecorse River as a part of the 2019 sampling event (details for which are below).  The Michigan Department of Environment, Great Lakes, and Energy (EGLE), Water Resources Division (WRD), added the watershed to its PFAS sampling strategy in 2020.  The watershed, along with the Frank and Poet drain watershed, was sampled for PFAS in August 2020.  This sampling found elevated levels of PFOS throughout the watershed.  EGLE will be conducting additional investigations to identify sources of PFAS in the Ecorse River Watershed.

Next Steps

  • EGLE’s Fish Contaminant Monitoring Program plans to collect fish from the Ecorse River in 2021 and analyze the samples for PFAS.
  • EGLE will use the August 2020 surface water sample data to continue our PFAS source tracking efforts within the watershed in order to identify potential sources.
  • In 2020 - 2021, the Wyandotte Municipal Services drinking water plant and GLWA will begin 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.

Investigation Timeline

  • April 2019

    • April 30 - As part of a compliance sampling inspection, samples were collected by EGLE at Detroit Metro Wayne County Airport (DTW) from Outfall 006.  The discharge from Outfall 006 consists of treated deicing operations runoff and treated storm water runoff. Results for PFOS and perfluorooctanoic acid (PFOA) were 74 part per trillion (ppt) and 28 ppt, respectively. The PFOS result exceeded the surface water quality standard (WQS) of 12 ppt.  The discharge from Outfall 006 goes to the Frank and Poet Drain.

    May 2019

    • May 2 - As part of a compliance sampling inspection, samples were collected by EGLE at DTW from Outfall 003. The discharge from Outfall 003 consists of treated deicing operations runoff and treated storm water runoff. Results for PFOS and PFOA were 43 ppt and 26 ppt, respectively. The PFOS result exceeded the WQS of 12 ppt. The discharge from Outfall 003 goes to the Sexton and Kilfoil Drain.

    July 2019

    • July - Marathon Petroleum Company collected storm water and groundwater samples to be analyzed for PFAS. These samples were collected due to a Violation Notice issued by the Great Lakes Water Authority requiring Marathon to provide data to characterize PFAS in the storm water which is discharged to the Great Lakes Water Authority Water Resource Recovery Facility. Results confirmed some samples exceeded the groundwater water cleanup criteria at the time of 70 ppt PFOS + PFOA.

    August 2019

    • August 9 - EGLE issued a compliance communication letter to DTW requiring the airport to develop a PFAS source identification study plan to identify on-site PFAS sources.
    • August 27 - As one of approximately 70 community water supplies in Michigan which utilize surface water as a drinking water source, Wyandotte Municipal Services drinking water plant participated in monthly sampling for PFAS in raw and finished water in 2019 for six months. On this date, the fifth of six-monthly samples was collected. This sample had abnormally high PFAS results compared to those found in the previous four months. (See October 8, 2019 for results)
    • August 30 - DTW submitted their PFAS source identification study plan to EGLE.

    September 2019

    • September 22 - EGLE approved, with modifications, a work plan submitted by US Ecology Romulus, for conducting an initial investigation of PFAS on-site per EGLE's request.
    • September 24 - Regularly-scheduled monthly PFAS samples (month six of six) collected at the Wyandotte Municipal Services drinking water plant. The results were non-detect for all tested PFAS compounds.
    • September 30 - EGLE requested Marathon Petroleum Company to investigate the site for PFAS due to elevated concentrations of PFOS in the drainage ditch traversing the northern property boundary.

    October 2019

    • October 4 - DTW submitted sampling results from sampling of Outfall 003 and Outfall 006.  The highest result for PFOS was 34 ppt and PFOA was 40 ppt from Outfall 003, which discharges to the Sexton and Kilfoil Drain.  The highest result for PFOS was 40 ppt and for PFOA was 18 ppt from Outfall 006, which discharges to the Frain and Poet Drain.
    • October 8 - EGLE received the results of the August 27, 2019, sample event at the Wyandotte Municipal Services drinking water plant, which had abnormally high levels of PFOS and perfluorohexane sulfonate (PFHxS) in both raw (49 ppt PFOS and 6 ppt PFHxS) and treated water (26 ppt PFOS and 4 ppt PFHxS).
    • October 9 - EGLE and Michigan Department of Health and Human Services (MDHHS) staff met to discuss the sample results and mobilized EGLE's contractor, AECOM, to begin weekly sampling of raw and treated water at the Wyandotte Municipal Services drinking water plant, as well as the nearby Great Lakes Water Authority Southwest (GLWA SW) Plant.  Over the course of several meetings through January, EGLE and MDHHS discussed additional steps to conduct source tracking through surface water sampling and direct discharge sampling of National Pollutant Discharge Elimination System permitted industries.   
    • October 18 - First weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds.
    • October 24 - Second weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds.
    • October 31 - Third weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds.

    November 2019

    • November 7 - Fourth weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds.
    • November 14 - Fifth weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds.
    • November 20 - EGLE staff collected surface water samples on the Rouge, Ecorse, and Detroit Rivers in response to the PFOS and PFHxS detections at the Wyandotte Municipal Services drinking water plant.
    • November 20 - Sixth weekly round of PFAS samples collected at the Wyandotte Municipal Services drinking water plant and GLWA SW Plant.  The results were non-detect for all tested PFAS compounds. Having observed 6 weeks of weekly sample results without PFAS detections in raw or finished water, Wyandotte transitioned to continued quarterly monitoring consistent with a detection > 10 ppt total tested in their finished water (see March 27, 2020).

    December 2019

    • December 21 - EGLE received surface water sampling results from the November 20 sampling event. The PFOS concentrations in the Ecorse River exceeded the WQS of 12 ppt PFOS.  This led to additional sampling.

  • January 2020

    February 2020

    • February 14 - EGLE approved the DTW PFAS source identification study plan.

    March 2020

    • March 6 - EGLE received funding to determine the presence of PFAS in public water supplies around the state.   AECOM was mobilized to continue quarterly PFAS sampling of approximately 80 select public water supplies in Michigan.  These included all supplies which had returned detections of at least 10 ppt total tested PFAS in finished water and included the Wyandotte Municipal Services drinking water plant treated drinking water.
    • March 23 - DTW requested an extension to gather PFAS samples related to the PFAS source identification study until the COVID stay-home order was lifted.  This request was reviewed and approved by EGLE.
    • March 27 - First quarterly round of 2020 PFAS sample were collected at the Wyandotte Municipal Services drinking water plant.  The results were non-detect for all tested PFAS compounds.

    May 2020

    • May 28 - US Ecology Romulus became an official Michigan PFAS Action Response Team site. Sampling occurred here based on a request from EGLE due to a fire that occurred at the facility in 2005 and where aqueous film forming foam (AFFF) was believed to have been used. Results confirmed one sample exceeded the groundwater water cleanup criteria at the time of 70 ppt PFOS + PFOA.  

    June 2020

    • June 24 - Second quarterly round of 2020 PFAS sample collected at the Wyandotte Municipal Services drinking water plant. The results were non-detect for all tested PFAS compounds.

    July 2020

    • July 1 - A request for proposals for municipal airport operators PFAS funding was issued by the Michigan Department of Transportation (MDOT).  DTW was among the first round of municipal airport operators to receive grant funding to support monitoring and testing for PFAS contamination.
    • July - EGLE and BASF-Northworks Wyandotte conducted a groundwater investigation and detected PFOS, PFOA, and perfluorohexane sulfonate (PFHxS), in the groundwater at the site in the vicinity of the three extraction well fields that are mandated by a State of Michigan Consent Decree since 1985/86, as well as a United States Environmental Protection Agency (USEPA), Order on Consent since 1994, that requires BASF to prevent discharges of contaminated groundwater to the Detroit River. Six of the groundwater samples exceeded the EGLE Part 201 Drinking Water Criteria for PFOS of 16 ppt. Five of the groundwater samples exceeded the EGLE Part 201 Drinking Water Criteria for PFOA of 8 ppt.

    August 2020

    • August 11 - EGLE collected surface water samples throughout the Ecorse River and Frank and Poet Drain watersheds. This sampling occurred as a result of the elevated PFOS levels identified from the November 20, 2019 sample event.
    • August 25 - The PFAS work plan proposal for DTW was approved for funding after review by EGLE staff.

    September 2020

    • September 4 - EGLE received surface water PFAS results from the August 11 sampling event. Several sampling locations in both the Ecorse River and Frank & Poet Drain watersheds exceeded the WQS of 12 ppt PFOS. The highest PFOS concentrations (151 ppt and 344 ppt) were found in two drains coming from the Detroit Metro Wayne County Airport property. 
    • September 9 - Marathon Petroleum Company became an official Michigan PFAS Action Response Team site. Marathon has identified the use of Aqueous Film Forming Foam (AFFF) in both the fire training area and areas of historic emergency response as sources of PFAS.  Marathon first used PFAS containing AFFF in the 1980s and during annual training until 2018.
    • September 24 - EGLE staff met to discuss the sample results from the Ecorse River and Frank and Poet Drain surface water sampling event and determine next steps. Additional surface water samples will need to be collected in areas with elevated results as part of source tracking efforts.
    • September 14 - DTW's airport grant was signed by MDOT, allowing the on-site testing to begin using grant funds. 
    • Investigation of PFAS in Michigan's Ecorse River and Frank and Poet Drain Watersheds: Surface Water Sampling Update September 2020

    October 2020

    • October 20 & 21 - Third quarterly round of 2020 PFAS sample is collected at the Wyandotte Municipal Services drinking water plant. The results were non-detect for all tested PFAS compounds.

    November 2020