North Post of Camp Grayling Area of Interest (Waters, Otsego & Crawford Counties)

Christian Bon, BonC@Michigan.gov or 989-370-9624.

The Army National Guard (ARNG) is currently sampling for PFAS at the North Post of Camp Grayling, including Range 40. This investigation is being conducted following the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) process due to information indicating the possibility of release of PFAS through use of firefighting foams and wetting agents. One round of groundwater samples was collected from a limited number of existing Range 40 monitoring wells during the Site Inspection (SI) stage of CERCLA. Results were shared with EGLE in November 2022.

Because the absence or presence of groundwater contamination at Range 40 is not fully investigated, MPART will conduct precautionary drinking water well sampling on the east side of Guthrie and Section One Lakes as well as between Jones Lake and southern Range 40.

Historically, Range 40 was monitored for metals and explosives associated with the active air-to-ground range. Based on sampling at Range 40, groundwater flow is to the southeast. Although, PFAS compounds had not been detected on site exceeding groundwater clean-up criteria or in lakes and streams exceeding Water Quality Values, additional characterization is necessary to understand the full extent of the groundwater contamination. Previous studies indicate a connection between groundwater and groundwater-fed lakes and rivers surrounding Range 40.

Range 40 lies within four watersheds: Chub Creek (northwestern range); Crapo Creek North Branch Au Sable River (northeastern range); Kyle Lake (southeastern range); and East Branch Au Sable River (central and southwestern range).

The groundwater-fed East Branch of the Au Sable River runs through the western side of Range 40 and connects groundwater-fed Barnes, River, and Jones Lakes. Shallow groundwater flow direction likely follows a southwesterly direction in the area of the East Branch Au Sable.

The headwater lakes on the northwestern portion of Range 40 and just off-site to the northwest - Marsh, Section One, and Guthrie Lakes - are hydraulically connected. Shallow groundwater flow direction possibly follows a more northerly direction in the area of the headwater lakes connected by Chub Creek.

There are numerous other investigations in this area that have become MPART sites: Camp Grayling - Lake Margrethe; Camp Grayling - MATES at Range 30 Grayling Army Airfield; and Grayling Wastewater Treatment Facility Discharge Fields.

There is currently no municipal water available in the areas. Residents are on private drinking water wells.

Of the 74 wells canvassed near Range 40 in April 2023, 35 have returned been sampled. Three wells had detections of PFAS below Michigan Drinking Water Criteria.

The two Jones Lake Campground wells were sampled. One well was non-detect for PFAS. The other well had detections of PFOA below Michigan Drinking Water Criteria for two rounds of sampling and the well was taken offline by the DNR.

EGLE is conducting precautionary private drinking water well sampling on the east side of Guthrie and Section One Lakes, closest to Range 40, as well as between Jones Lake and southern Range 40. Expanded residential drinking water well sampling will be dependent on the first round of residential drinking water well sampling.

Approximately 74 private wells will be included in the first round of precautionary sampling. Sample request forms were distributed to the residents on April 19, 2023. Drinking water sampling areas near Guthrie and Section One Lakes include Fantasy Drive, Grimm Court, Wagner Drive, Guthrie Court, Legend Drive, Wilhelm Lane and Rogers Road. Drinking water sampling areas between Range 40 and Jones Lake include along Kinney Road and Co Road 612 immediately east of the East Branch Au Sable River. EGLE also sampled the campground wells at Jones Lake Campground.

North Post Supplemental SI Field Activities to be conducted Fall 2023 with SI Report expected mid-2024. A decision regarding the necessity of additional investigative steps will be made based on the findings of the Supplement SI report.