Please contact the Site Lead for the most up-to-date status of this site.
These plants receive residential, commercial, and sometimes industrial wastewater that may contain PFAS. Conventional wastewater treatment plants are not designed to treat for PFAS, therefore PFAS may pass through the treatment system to surface waters (i.e., lakes, rivers, etc.) and groundwater. EGLE is actively working with these wastewater treatment plants to address PFAS.
For more information, please see the Wastewater Workgroup page.
The city of Grayling operates the Grayling Wastewater Treatment Facility (WWTF), which is an approximately 35-acre wastewater treatment system that went into operation in 1990. The WWTF includes 5 wastewater lagoons that are lined with a PVC membrane and underlain by geosynthetic clay liner. The wastewater lagoons discharge to irrigation fields approximately 145 acres in area and three-quarters of a mile east of the WWTF at the south end of Industrial Street. The irrigation fields have monitoring wells that are sampled biannually in accordance with the groundwater discharge permit issued by EGLE’s Water Resources Division (WRD). The results of the analyses are submitted to WRD as required. Historically, analyses required by the groundwater discharge permit have not included PFAS.
On June 11, 2020, at the request of EGLE’s Remediation and Redevelopment Division (RRD), the city of Grayling allowed EGLE contractors to sample the groundwater using two of the WWTF’s monitoring wells at the northern end of the irrigation fields. RRD’s request was based upon recent reports of foam on Shellenbarger Lake and the possibility that Grayling Army Airfield (MPART site) contamination was making its way into the sanitary sewer system.
The sampling results identified PFOA, PFOS, and other PFAS compounds in the two groundwater monitoring wells. PFOA and PFOS were identified at concentrations exceeding Part 201 Drinking Water Cleanup Criteria for PFOA and PFOS at 8 ppt and 16 ppt, respectively.
Shallow groundwater flows to the north toward Shellenbarger Lake, while the deeper groundwater aquifer is estimated to flow in a more northeasterly direction. EGLE is working with the city of Grayling to identify potential sources in the sanitary sewer system and to identify receptors downgradient of the discharge fields.
Content posted August 2022.
See an aerial view of the location of the site.
EGLE in coordination with the Michigan Department of Health and Human Services and the local health department will expand residential well sampling if determined to be necessary.
EGLE will continue to work with the city of Grayling to identify and reduce sources of PFAS contamination to the WWTF.
|
Type of Sample |
Date Sampled |
Number of Sample Results Received |
Number of Samples AboveCriteria |
|---|---|---|---|
| Residential Wells | October 2020 | 15 | 0 |
| Groundwater Monitoring Wells | June 2020 - May 2022 | 3 | 2 |
* 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).
