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Chrysler Scio Introl Division (Dexter, Washtenaw County)

EGLE Site Lead: Joseph Rogers, RogersJ5@Michigan.gov or 517-555-5312. Webpage last updated: May 17, 2021.

Background

The former Chrysler Scio Introl Division is located at 2880 Zeeb Road, Dexter.  This facility was a former Chrysler plant that historically conducted several manufacturing operations related to the automobile industry, including plating.  The facility is regulated as a hazardous waste treatment, storage, and disposal facility and is required to conduct actions to eliminate any potential exposures to contamination at the site.  Such corrective actions have been ongoing for approximately 10 years.  In 2018 PFAS was detected; however, the results were below the 70 ppt criteria.  In 2019, further investigation detected concentrations above the 70 ppt criteria on the portion of the site that is away from the river.

The site is located on the Huron River.  Groundwater flows to the south/southeast, toward the Huron River.  The city of Ann Arbor uses water from the Huron River as part of its drinking water supply; an intake is located downstream, approximately four miles from the site.

Chrysler Scio Facility Map

Recent Accomplishments

  • On September 23, 2020, October 7, 2020, and January 4, 2021, respectively, EGLE received the first three phases of a feasibility study reviewing potential options for PFAS remediation at the site.

Next Steps

  • The next steps of the investigation include additional monitoring and an initial feasibility evaluation of potential remedial alternatives.
  • A groundwater sampling event at the facility to confirm the current delineation of contamination is scheduled for the first week of June 2021.

Residential Well Testing/Alternate Water Information

  • The historical on-site supply was sampled and analyzed twice.  The most recent event was on March 13, 2020 and had a PFOA concentration of 1.9 ppt detected which is below the drinking water standard of 8 ppt.  No other PFAS compounds were detected. In December 2020, the facility installed two new potable wells, and on December 14, 2020 both of the new wells were sampled.  No regulated PFAS compounds were detected in either well. 
  • All on-site contamination appears to be venting to the Huron River; however, out of abundance of caution the local health department sampled six nearby residential wells over the week of September 21, 2020. The results of this testing showed four wells with no PFAS compounds detected, and the other two wells had very low levels of PFAS compounds detected, well below drinking water criteria and not thought to be related to impacts from the Chrysler Scio site  

Upcoming Community Engagement

  • None scheduled at this time; however, a public meeting may be scheduled in association with the residential well sampling if determined to be necessary.

Sampling Results Summary

This table was updated to include all seven PFAS criteria effective December 21, 2020.

Type of Sample

Date Sampled (or Range)

Number of Sample Results Received

Number of Samples above Criteria*

Residential Wells

August 17, 2018 - March 13, 2020 9 0
 Groundwater Monitoring Wells May 24, 2018 - March 12, 2020  65 39
 Surface Water  February 2019 5 0
*Residential well and groundwater monitoring well results are compared to EGLE Part 201 criteria for 7 PFAS compounds:  PFOS (16 ppt), PFOA (8 ppt), PFNA (6 ppt), PFHxS (51 ppt), PFHxA (400,000 ppt), PFBS (420 ppt), and HFPO-DA (370 ppt).
*Surface water samples are compared to Rule 57 non-drinking water values of 12 ppt for PFOS and 12,000 ppt for PFOA. 

Sampling Notes

  • On August 3, 2020, new Part 201 Criteria went into effect.  Historical sampling data compared to Part 201 Criteria >70 is captured in the historical timeline below.

Historical Timeline

    • On March 12, 2019, the facility's consultant collected groundwater samples.
    • On April 30, 2019, EGLE received the results of the March sampling event.  The highest PFOS+PFOA groundwater result was 1,700 ppt.
    • In the summer of 2019, additional plume delineation and source investigation were conducted.
    • On October 22, 2019, EGLE received the initial draft report of the work performed in the summer of 2019.  The data in the report indicates PFOS concentrations is venting to the Huron River above criteria at one location.
    • On December 4, 2019, EGLE provided comments on the draft report and recommended next steps of investigation to the facility.  
    • On January 16, 2020, a new map was updated to this webpage.
    • On February 21, 2020, EGLE approved the next steps of the investigation.  Implementation of the additional investigation was initiated in March and April 2020. 
    • On March 13, 2020, the on-site water supply well was sampled and had a PFOA concentration of 1.9 ppt which is below the drinking water standard of 8 ppt.  No other PFAS compounds were detected. 
    • On June 8, 2020 a draft Report including the results of the additional investigation was received.  EGLE sent comments on July 16, 2020 and a final report was submitted on July 22, 2020.
    • On September 23, 2020, October 7, 2020, and January 4, 2021, respectively, EGLE received the first three phases of a feasibility study reviewing potential options for PFAS remediation at the site.

Sampling Results: PFOS and PFOA Only

Type of Sample

Date Sampled (or Range)

Number of Samples

Number of Results Received

Number of Non-Detects  Number Between Non-detect and Standard*  Number Greater Than or Equal to Standard 

Groundwater Monitoring Wells

2018 - August 3, 2020 53 53 6 41 6
 Stormwater Outfalls February 2019 5 5 1 4 0
 Cumulative   58 58 7 45 6

*Groundwater results are compared to EGLE Part 201 Criteria of 70 ppt PFOS+PFOA. *Surface water samples are compared to Rule 57 non-drinking water values of 12 ppt for PFOS   and 12,000 ppt for PFOA.