Dow Chemical ITI Facility (Bay City, Bay County)

• Between December 2017 and June 2020, Dow Chemical's environmental consultants have collected a total of 43 groundwater samples from a sump, extraction wells, monitoring wells, and effluent.
• On March 18, 2020, Arcadis, Dow Chemical's environmental consultant, collected one groundwater sample from a sump that handles the output from the site groundwater extraction wells.
• In the first quarter of 2020, an average of 23,331 gallons of water were pumped per day to the WWTP, which is within the permit maximum average of 25,000 gallons per day.  Groundwater level surveys were completed 8 times between January and March 2020.  During the first quarter of 2020, groundwater elevations were intermittently above the Saginaw River elevation.  As a response, an additional extraction well (EW-5) was turned on to lower the groundwater levels.
• On April 30, 2020, EGLE received the sample results from Arcadis.  The results indicated concentrations of PFOA at 10 ppt and PFNA at 14 ppt.
• Between May 11, 2020 and July 13, 2020, EGLE communicated with Arcadis to schedule a meeting to discuss the PFAS compounds that were detected.
• In the second quarter of 2020, a total of approximately 2,053,514 gallons of water were pumped to the WWTP.  Groundwater level surveys were completed 7 times between April and June 2020.  During the second quarter of 2020, groundwater elevations were intermittently above the Saginaw River elevation.  As a response, an additional extraction well (EW-5) was turned on and operated intermittently to lower the groundwater levels.
• On April 30, 2020, EGLE received the sample results from Arcadis.  The results indicated concentrations of PFOA at 10 ppt and PFNA at 14 ppt.
• Between May 11, 2020 and July 13, 2020, EGLE communicated with Arcadis to schedule a meeting to discuss the PFAS compounds that were detected.
• On July 29, 2020, EGLE received the most recent sample results from Arcadis, Dow Chemical's environmental consultant.  The results indicated concentrations of PFOA at 18 ppt and PFNA results were non-detect.
• On July 29, 2020, EGLE met with Dow Chemical to discuss PFAS results.  During the meeting, Dow Chemical explained that four rounds of groundwater sampling have been conducted from four extraction wells and a drinking water restriction is in place for the site.  Based on EGLE file review, the information provided during the meeting, and the lack of drinking water wells in the area, EGLE does not intend to request expanded PFAS sampling at this time.
• In August 2020, EGLE reviewed additional file information which included an additional 42 groundwater samples that were collected from the site since 2017.

Historical Sampling Table

*Groundwater results are compared to EGLE Part 201 Criteria of PFOS 16 ppt and PFOA 8 ppt.

• On September 16, 2020, MPART hosted a regional webinar to educate the public about sites with PFAS contamination exceeding the new groundwater clean-up standards.  A presentation of this site was included in the webinar:
  • September 16, 2020 Bay City Regional Webinar Recording
  • September 16, 2020 Bay City Regional Webinar Presentation
• On October 30, 2020, EGLE received the Third Quarter 2020 Monitoring Report submitted by the liable party.  The report included one groundwater sample collected at a sump and one duplicate groundwater sample, also collected at the sump.  The analytical results indicate PFOA at a concentration of 18 ppt in each of the two samples.  In the third quarter of 2020, a total of approximately 4,464,277 gallons of water were pumped to the WWTP.  Groundwater level surveys were completed 11 times between July and September 2020.  During the third quarter of 2020, groundwater elevations were below the Saginaw River elevation, with the exception of one piezometer (P-1) on two occasions.

• On January 29, 2021, EGLE received the Fourth Quarter 2020 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump and one duplicate groundwater sample, also collected at the sump. The analytical results indicate that several PFAS compounds were detected at concentrations that did not exceed their respective EGLE Part 201 criteria. In the fourth quarter of 2020, a total of approximately 3,348,148 gallons of water were pumped to the WWTP. Groundwater level surveys were completed 12 times between October and December 2020.During the fourth quarter of 2020, groundwater elevations were below the Saginaw River elevation, with the exception of piezometer (P-1) on seven occasions; piezometer (P-3) on three occasions; piezometer (P-9) on one occasion; piezometer (P-13B) on one occasion; piezometer (P-14B) on three occasions; piezometer (P-15B) on three occasions; and piezometer (P-16B) on one occasion.
• On April 30, 2021, EGLE received the First Quarter 2021 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump and one duplicate groundwater sample, also collected at the sump. The analytical results indicate that several PFAS compounds were detected at concentrations that did not exceed their respective EGLE Part 201 criteria. In the first quarter of 2021, a total of approximately 2,551,460 gallons of water were pumped to the WWTP. Groundwater level surveys were completed 7 times between January and March 2021.During the first quarter of 2021, groundwater elevations were below the Saginaw River elevation, with the exception of piezometer (P-1) on five occasions; piezometer (P-3) on three occasions; piezometer (P-11) on two occasions; piezometer (P-13B) on two occasions; piezometer (P-14B) on three occasions; and piezometer (P-15B) on three occasions.
  
  • On May 6, 2021, the Bay County Health Department confirmed that no residential water wells are located near the site.
  • On July 29, 2021, EGLE received the Second Quarter 2021 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump. The analytical results indicate PFOA at a concentration of 32 ppt and PFNA at a concentration of 360 ppt. In the second quarter of 2021, a total of approximately 4,367,464 gallons of water were pumped to the WWTP. Groundwater level surveys were completed 13 times between April and June 2021.During the second quarter of 2021, groundwater elevations were below the Saginaw River elevation, with the exception of piezometer (P-1) on four occasions; piezometer (P-3) on two occasions; piezometer (P-13B) on one occasion; piezometer (P-14B) on one occasion; and piezometer (P-15B) on three occasions.
  • On October 28, 2021, EGLE received the Third Quarter 2021 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump. The analytical results indicate PFOA at a concentration of 21 ppt and PFNA at a concentration of 580 ppt. In the third quarter of 2021, a total of approximately 4,241,598 gallons of water were pumped to the WWTP. Groundwater level surveys were completed 12 times between July and September 2021.During the third quarter of 2021, groundwater elevations were below the Saginaw River elevation, with the exception of eight piezometers (P-1, P-3, P-7, P-11, P-13B, P-14B, P-15B, and P-16B) on one occasion and piezometer (P-9) on two occasions.

• On February 1, 2022, EGLE received the Fourth Quarter 2021 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump. The analytical results indicate that no PFAS compounds were detected at concentrations exceeding reporting limits; However, it should be noted, reporting limits were significantly elevated in the laboratory report. In the fourth quarter of 2021, a total of approximately 4,012,378 gallons of water was pumped to the WWTP. Groundwater level surveys were completed 11 times between October and December 2021.During the fourth quarter of 2021, groundwater elevations were below the Saginaw River elevation, with the exception of piezometer (P-1) on five occasions, piezometer (P-3) on three occasions, piezometer (P-7) on one occasion, piezometer (P-9) on four occasions, piezometer (P-11) on one occasion, piezometer (P-13B) on three occasions, piezometer (P-14B) on three occasions, and piezometer (P-15B) on three occasions.
• On April 29, 2022, EGLE received the First Quarter 2022 Monitoring Report submitted by the liable party. The report included one groundwater sample collected at a sump. The analytical results indicate PFNA at a concentration of 64 ppt. In the first quarter of 2022, a total of approximately 2,876,148 gallons of water were pumped to the WWTP. Groundwater level surveys were completed 7 times between January and March 2022.During the first quarter of 2022, groundwater elevations were below the Saginaw River elevation with the exception of seven piezometers (P-3, P-7, P-9, P-13B, P-14B, P-15B, and P-16B) on one occasion, piezometer (P-1) on two occasions, and piezometer (P-11) on three occasions.

Sampling Results Summary

* 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).

Sampling notes

• None at this time.