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City of Mackinac Island Landfill (Mackinac Island, Mackinac County)

EGLE Site Lead: Mary Ann St. Antoine, StantoineM@Michigan.gov. Last Updated: March 11, 2022

Background

Mackinac Island Landfill is located at 3883 Dousman Road and near the center of Mackinac Island. The 26‑acre landfill was operated by the city of Mackinac Island on land leased from the State of Michigan. It was a municipal solid waste landfill that operated from 1965 to 1993 and received solid waste generated from residential, commercial, and state park activities and wastewater sludge. The unlined landfill was initially unlicensed and then later licensed under Garbage and Refuse Disposal, 1965 PA 87, as amended, and Solid Waste Management, 1978 PA 641, as amended. In 1980, an extensive groundwater investigation showed groundwater contamination at the site. This resulted in a Consent Order, and the city of Mackinac Island agreed to close, properly cap, install a leachate collection system, and implement a groundwater monitoring program. A Remedial Action Plan (RAP) was completed in 1990, to address the presence of volatile organic compounds (VOCs) and dissolved metals in the groundwater. Current activities on the site include a horse manure compost system and a solid waste processing plant. The Mackinac Island Community Equestrian Center uses the south cell of the landfill as a horse turn out area.

Due to the diverse material disposed of at the site and groundwater impacts at the landfill, EGLE requested that the city of Mackinac Island sample select wells for PFAS.

The groundwater flows to the northeast and is underlain by a complex geology composed of fractured bedrock and unconsolidated sand, silt, and gravel. There are no drinking water wells on Mackinac Island.

Recent Accomplishments

  • On October 26, 2021, and November 17, 2021, Mackinac Environmental Technology, Inc., staff collected five groundwater samples from four monitoring wells (including a duplicate sample at MW-5), and one sample from the purge well leachate collection system. 
  • On December 7, 2021, EGLE received the sample results. All samples from the four monitoring wells and the purge well exceeded groundwater criteria for PFOA; monitoring wells MW-5, MW-8, MW-9, and the purge well exceeded groundwater criteria for PFOS; and monitoring well MW-9 exceeded groundwater criteria for PFNA.

Next Steps

  • Continued groundwater monitoring of the landfill.  

Residential Well/Alternate Water

  • There are no residential wells on Mackinac Island.

Upcoming Community Engagement

  • None scheduled at this time.

Sampling Results Summary

Type of Sample

Date Sampled (or Range)

Number of Sample Results Received

Number of Samples above Criteria*

Groundwater Monitoring Wells

October 26, 2021 - November 17, 2021 5 5

 

* Residential well and groundwater monitoring well results are compared to EGLE Part 201 criteria for 7 PFAS compounds effective 12/21/2020:  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.