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Clinton River / Lake St. Clair Watershed

The Clinton River drains portions of five counties in southeast Michigan. The Clinton River Watershed drains 760 square miles and flows 83 miles from its headwaters to Lake St. Clair. Lake St. Clair connects Lake Huron to its north with Lake Erie to its south. The Michigan Department of Environment, Great Lakes, and Energy (EGLE) began sampling in the Clinton River due to the discovery of perfluorooctanesulfonic acid (PFOS) in the river at levels over the Rule 57 water quality value (WQV) of 11 ppt PFOS.

Reports

Investigation Timeline

    • On August 31, EGLE collected surface water samples from the Clinton River near its mouth and along the Lake St. Clair shoreline just north of the Selfridge Air National Guard Base (Selfridge ANGB) in Harrison Township. Sampling was conducted as part of a targeted monitoring effort to identify surface waters that could have elevated levels of PFAS. Both samples exceeded the WQS for PFOS.
      • Clinton River upstream of river mouth – 36 ppt PFOS and 5 ppt PFOA.
      • Lake St. Clair at Selfridge Public Boat Launch – 180 ppt PFOS and 4.3 ppt PFOA.
    • On October 26, EGLE collected effluent samples from three area wastewater treatment plants.
      • The Mt. Clemens WWTP effluent contained 7.4 ppt PFOS and 14 ppt PFOA.
      • The Pontiac WWTP effluent contained 9 ppt PFOS and 13 ppt PFOA.
      • The Warren WWTP effluent contained 14 ppt PFOS and 11 ppt PFOA.
      • For more information on the regulation of PFAS discharges from wastewater treatment plants, visit the MPART Wastewater Treatment Plants / Industrial Pretreatment Program.
    • On November 7, as a follow-up to the August sampling event EGLE collected surface water samples from the Clinton River and Lake St. Clair, and fish samples from Lake St. Clair.
      • None of the surface water samples from Lake St. Clair exceeded the WQS. The mean PFOS concentration for samples from Lake St. Clair was 2.9 ppt.
      • Surface water results from samples collected at the Clinton River at Moravian Drive – 470 ppt PFOS and 6 ppt PFOA.
      • Replicate surface water samples collected in the Clinton River along the southern border of Selfridge ANGB exceeded the WQS for PFOS. However, there was a high degree in variability between the two samples (31 ppt and 610 ppt PFOS).
      • Michigan Department Health and Human Services (MDHHS) issued a fish consumption advisory for bluegill and sunfish from Lake St. Clair as a result of PFOS concentrations. For additional information, please visit the MDHHS Eat Safe Fish webpage.
    • In November, as a follow-up to the August sampling event, downstream drinking water systems in the Detroit River and lower Lake St. Clair were sampled in advance of EGLE’s Statewide Testing Initiative. All results were non-detect. For more information on testing for PFAS in public water supplies, including test results, visit the MPART Statewide Sampling Survey webpage.

    Clinton River Watershed - Figure 2 - PFOS in August 2017 surface water samples
    PFOS (in ppt) in August 2017 surface water samples from the Clinton River and Lake St. Clair.

    Clinton River Watershed - Figure 3 - PFOS in November 2017 surface water samples
    PFOS (in ppt) in November 2017 surface water samples from the Clinton River and Lake St. Clair.

    • In January, EGLE sampled the raw and finished drinking water from the Ira Township, New Baltimore, and Mount Clemens drinking water plants. While PFAS were detected, the combined levels of PFOS and PFOA were well below the Lifetime Health Advisory of 70 ppt. Subsequent testing in October of 2018 did not detect PFAS in treated water from any of these facilities. For more information on testing for PFAS in public water supplies, including test results, visit the MPART Statewide Sampling Survey page
    • On February 13, EGLE collected additional surface water samples in the Clinton River and its tributaries. One sample from Greiner Drain, a tributary to the North Branch of the Clinton River, contained 43 ppt PFOS and 16 ppt PFOA. This exceeds the WQS for PFOS.
    • EGLE’s sampling of area wastewater treatment plants continued in the fall of 2018:
      • On September 14, the effluent from the Warren WWTP was non-detect for PFOS.
      • On November 14, as part of the Statewide Biosolids Survey, the effluent at Pontiac WWTP was sampled. The PFOS concentration was 20 ppt; the PFOA concentration was 38 ppt.
      • On November 15, as part of the Statewide Biosolids Survey, the effluent at Mt. Clemens WWTP and Warren WWTP was sampled. At Mt. Clemens, the PFOS concentration was 3.4 ppt; the PFOA concentration was 9 ppt. At Warren WWTP, the PFOS and PFOA concentrations were non-detect.
      • On November 29, the effluent from the Warren WWTP was non-detect for PFOS. 
    • On October 29, 2018, Selfridge Air National Guard Base (ANGB) became an official Michigan PFAS Action Response Team site.

    Clinton River Watershed - Figure 4 - PFOS in February 2018 surface water samples
    PFOS (in ppt) in February 2018 surface water samples from the Clinton River and Lake St. Clair.

    • As part of the ongoing sampling effort of WWTPs:
      • On February 14, the effluent from the Warren WWTP was Non-Detect for PFOS.
      • On February 27, the effluent from the Pontiac WWTP was 24 ppt for PFOS.
      • On May 17, the effluent from the Pontiac WWTP was 41 ppt for PFOS.
      • On May 24, the effluent from the Warren WWTP was Non-Detect for PFOS.
      • On August 9, the effluent from the Pontiac WWTP was 48 ppt for PFOS.
      • On September 16, the effluent from the Warren WWTP was 16 ppt for PFOS.
      • On October 2, the effluent from the Pontiac WWTP was 45 ppt for PFOS.
      • On November 15, the effluent from the Warren WWTP was 12 ppt for PFOS.
    • From April through September of 2019, EGLE conducted monthly sampling of the raw and finished drinking water from the Ira Township, New Baltimore, and Mount Clemens drinking water plants. PFAS was not detected in the Ira Township or New Baltimore samples, while samples from Mount Clemens contained a maximum of 5 ppt of combined PFOS and PFOA in both untreated and treated drinking water. For more information on testing for PFAS in public water supplies, including test results, refer to the MPART Statewide Testing Initiative webpage.
    • On July 26, EGLE staff conducted surface water sampling in the Clinton River watershed to follow up on previous sampling efforts. One sample from the Clinton River, at Gratiot Avenue in Mount Clemens, measured at the WQS with 12 ppt of PFOS. Several tributaries also contained PFOS at or above WQS. Overall, samples from the Clinton River (including its north branch) ranged from 2–12 ppt for PFOS and 2–7 ppt for PFOA. Samples from tributaries ranged from 8–190 ppt for PFOS and 5–36 ppt for PFOA.
    • In 2019, EGLE staff collected 10 rock bass from upstream of Yates Dam for PFAS analysis. The average PFOS was 13.93 ppb, ranging from 6.14–28.60 ppb.
    • On December 13, EGLE Water Resources Division (WRD) conducted a compliance inspection at the Selfridge Plating facility located on Irwin Drive.

    Clinton River Watershed - Figure 5 - PFOS in July 2019 surface water samples
    PFOS (in ppt) in July 2019 surface water samples from the Clinton River and Lake St. Clair.

      • As part of the ongoing sampling effort of WWTPs:
        • On January 15, the effluent from the Pontiac WWTP was 11 ppt for PFOS.
        • On January 29, the effluent from the Warren WWTP was <10 ppt for PFOS.
        • On April 21, the effluent from the Pontiac WWTP was 9.2 ppt for PFOS.
        • On May 8, the effluent from the Warren WWTP was <10 ppt for PFOS.
        • One June 11, the effluent from the Pontiac WWTP was 11 ppt for PFOS.
        • On June 17, the effluent from the Pontiac WWTP was 12 ppt for PFOS.
        • On July 10, the effluent from the Pontiac WWTP was 9.2 ppt for PFOS.
        • On September 9, the effluent from the Warren WWTP was <10 ppt for PFOS.
        • On October 14, the effluent from the Pontiac WWTP was 5.7 ppt for PFOS.
        • On October 30, the effluent from the Warren WWTP was 13 ppt for PFOS.
    • As part of the ongoing sampling effort of WWTPs:
      • On February 10, the effluent from the Warren WWTP was 5.5 ppt for PFOS.
      • On April 9, the effluent from the Warren WWTP was 6.1 ppt for PFOS.
      • On August 31, the effluent from the Warren WWTP was 7.8 ppt for PFOS.
      • On November 5, the effluent from the Warren WWTP was 11.7 ppt for PFOS.
      • On November 17, the effluent from the Mount Clemens WWTP was 4.78 ppt for PFOS.
      • On December 3, the effluent from the Warren WWTP was 13 ppt for PFOS.
    • In 2021, EGLE conducted bi-monthly monitoring of the raw and finished drinking water from the Ira Township, New Baltimore, and Mount Clemens drinking water plants. PFAS was not detected in the Ira Township or New Baltimore samples. Samples from Mount Clemens contained a maximum of 2 ppt PFOA in untreated water and 3 ppt PFOA and 3 ppt PFOS in treated drinking water. For more information on testing for PFAS in public water supplies, including test results, visit the MPART Statewide Sampling Survey webpage.
    • On March 9, 2021, EGLE staff conducted surface water sampling in the upper portion of the Clinton River watershed to follow up on previous sampling efforts. One sample from an unnamed tributary approached the Rule 57 WQV with 11.7 ppt of PFOS. Overall, samples from the Clinton River contained 1.62–5.11 ppt PFOS and 1.77–3.85 ppt PFOA. Samples from lakes and tributaries within the watershed contained 1.53–11.7 ppt PFOS and 1.58–5.31 ppt PFOA.
    • On March 26, 2021, Axalta Coating Systems became an official Michigan PFAS Action Response Team site.

    PFOS (in ppt) in March 2021 surface water samples from the Clinton River Watershed

    PFOS (in ppt) in March 2021 surface water samples from the Clinton River Watershed.

    • As part of the ongoing sampling effort of WWTPs:
      • On January 6, the effluent from the Warren WWTP was 9.4 ppt for PFOS.
      • On January 6, the effluent from the Pontiac WWTP was 6.5 ppt for PFOS.
      • On February 3, the effluent from the Warren WWTP was 5.2 ppt for PFOS.
      • On February 4, the effluent from the Pontiac WWTP was 4.1 ppt for PFOS.