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Middleground Landfill (Bay City, Bay County)

EGLE Site Lead: Loren Curtis, CurtisL@Michigan.gov or 989-274-0614. Webpage last updated April 21, 2020.

Background

Middleground Landfill is a closed municipal and industrial waste landfill located on Middleground Island in the Saginaw River. The landfill property was also a historic disposal site for Saginaw River dredge spoils. The west side of the landfill is immediately adjacent to the west channel of the Saginaw River; the east channel is approximately 300 feet from the east side of the landfill. Groundwater flow direction at Middleground Landfill is in a radial flow direction, flowing in all directions towards the Saginaw River’s west and east channels.

As part of the Industrial Pretreatment Program PFAS sampling initiative, the Bay City Wastewater Treatment Plant (WWTP) required PFAS landfill leachate sampling at Middleground Landfill. The WWTP receives and treats the landfill’s leachate. The leachate sample from the landfill was elevated for PFAS, which lead to EGLE requesting follow-up PFAS sampling at the closed landfill.

Aerial Map of Middleground Landfill

Recent Accomplishments

  • During the week of March 30, 2020, the PRP Group’s consultant performed well installation work and additional PFAS sampling.  They installed a total of seven new monitoring wells along the Northern, Southern, and Eastern boundaries of the landfill.  The seven new monitoring wells and 10 existing landfill monitoring wells (17 total) were then sampled for PFAS.

Next Steps

  • The PRP Group should receive the March 2020 PFAS sampling laboratory results by the end of April 2020.  Based on these results, the PRP Group will be making further decisions in regards to PFAS remedial investigation work.   
  • EGLE plans to collect additional Saginaw River watershed surface water samples for PFAS in 2020. 

Residential Well Testing/Alternate Water Information

  • There are no known groundwater drinking water wells on the island. Municipal drinking water is currently available to residents on the island.
  • The GSI pathway is the greatest concern at this site.

Upcoming Community Engagement

  • None scheduled at this time.

Sampling: PFOS and PFOA Only

Type of Sample

Date Sampled

Number of Samples

Number of Results Received

Number of Non-detects

Number Between Non-detect and standard*

Number of  > Standard

Groundwater August 2019 8 8 0 4 4
GSI Monitoring Wells August 2019 3 3 1 0 2
Surface Water October 2019 32 32 1 31 0

Cumulative

  43 43 2 35 6

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

Sampling Notes

  • Fish consumption advisories due to PFOS are already in place based on fish samples collected in 2013. 

Historical Timeline

    • On August 6, 2019, Middleground Landfill PRP Group consultant, GHD, collected samples from both groundwater and groundwater/surface water interface (GSI) monitoring locations.
    • On October 3, 2019, EGLE received the results from the August 2019 sampling event. The highest PFOS+PFOA groundwater concentration is located interior to the Middleground landfill site at a monitoring well near the southwest corner of the landfill.
    • On October 29, 2019, EGLE staff performed PFAS surface water sampling of the Saginaw River, including some tributary rivers and streams.  EGLE district staff received the surface water results on December 27, 2019, and all results were below water quality standards.  The “Investigation of Per- and Polyfluoroalkyl Substances (PFAS) in the Saginaw River Watershed: Surface Water Sampling October 2019” report can be found here.
    • On February 3, 2020, Middleground LF PRP Group held a conference call meeting with EGLE staff to review the next steps at the landfill.
    • During the week of March 30, 2020, the PRP Group’s consultant performed well installation work and additional PFAS sampling.  They installed a total of seven new monitoring wells along the Northern, Southern, and Eastern boundaries of the landfill.  The seven new monitoring wells and 10 existing landfill monitoring wells (17 total) were then sampled for PFAS.