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South Macomb Disposal Authority Landfill #11 (Washington Township, Macomb County)

EGLE Site Lead: Jim Bakun, BakumJ@Michigan.gov. Webpage last updated August 3, 2020.

Background

South Macomb Disposal Authority Landfill #11 (SMDA 11), located at 65921 Mound Road in Macomb County, is a closed municipal waste landfill. SMDA 11 was initially used as a sand and gravel mining operation prior to 1950. The 92-acre site consisted of two distinct disposal areas: Phase I and Phase II. From approximately 1950 into the 1960’s, Phase I operated as an unlicensed dump by Washington Township for its residents. Subsequently, the Phase I portion was utilized as a licensed landfill by various waste disposal companies, and SMDA from the 1960’s until 1979, when Phase II became the main disposal unit at SMDA 11. 

The various waste disposal units in Phase I were either unlined, or only partially lined, allowing leachate (liquids that contact the waste material) to migrate into the groundwater beneath the site. The Phase II portion of SMDA 11 was licensed under PA 641 and has a clay liner and perimeter leachate collection system.  Groundwater monitoring wells located around the perimeter of both Phase I and Phase II are sampled quarterly by SMDA.  Historical groundwater analytical data indicates that groundwater contamination is present at Phase I.  The existing groundwater contamination at Phase I has not been fully delineated. 

Based on the groundwater contamination and potential drinking water receptors near the site, EGLE requested that SMDA sample monitoring wells for PFAS analysis.

The groundwater flow direction at SMDA 11 is predominantly to the southwest west, although the south portion of Phase I does not have adequate monitoring well locations to delineate groundwater flow in that general area.  Potential groundwater receptors in the area include residential wells located within one-half mile of the site, and Stony Creek, part of the Clinton River Watershed.

Recent Accomplishments

  • In May 2019, EGLE requested that SMDA sample six (6) groundwater monitoring wells at SMDA 11 for PFAS analysis.
  • In November and December 2019, SMDA sampled six (6) groundwater monitoring wells.
  • On January 27, 2020, EGLE received the sample results.   Analytical results from one monitor well (MW-F) exceeded Part 201 Criteria for PFOA.  The result was 34 ppt PFOA and non-detect for PFOS.

Next Steps

  • EGLE will be requesting additional PFAS sampling at SMDA 11 to further identify the extent of PFAS in the groundwater at the landfill.   Additionally, EGLE will be requesting that SMDA initiate assessment monitoring at the site and develop a remedial action plan to address existing groundwater contamination at the site.

Residential Well Testing/Alternate Water Information

  • EGLE is working with the local health department to determine a future residential well sampling plan.

Upcoming Community Engagement

  • None scheduled at this time.

Sampling Results Summary: PFOS and PFOA Only

Type of Sample

Date Sampled (or Range)

Number of Sample Results Received

Number of Samples Above PFOS Criteria

Number of Samples Above PFOA Criteria 

Groundwater Monitoring Wells

November - December 2019 6 0 1
Cumulative   6 0 1

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

Sampling Notes

  • None at this time.