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General Motors Customer Care and Aftersales Facility (Waterford Township, Oakland County)

EGLE Site Lead: Nicole Sanabria, SanabriaN@Michigan.gov or 517-281-7726. Content last updated on June 7, 2022.

Background

General Motors Customer Care and Aftersales Facility (GM) is located at 5260 Williams Lake Road.  The site was built in 1954 by the Pontiac Coach Company and acquired by GM in 1969. Historically GM conducted painting operations from 1969 to 1989, with an accompanying wastewater treatment system. These have since been decommissioned and removed. Current operations are limited to warehousing of parts. EPA has been working with GM since the 1980’s on various clean-up activities.

In 2020, EPA requested GM sample for PFAS. PFAS was detected in groundwater monitoring wells.  The highest result was 310 ppt PFOA.  GM has installed additional downgradient monitoring wells to bracket known PFAS impacts near the water table. EPA is working with GM to address data gaps related to the PFAS release, including determining the extent of PFAS contamination in groundwater.

Soils at the site are primarily composed of sand and gravel with some clay. Some areas of the property have been filled in with sand to approximately 15 feet below ground. Groundwater flow is generally to the southeast, with the water table usually present ~10 feet below ground. Borings at the site show the sand and gravel  extends at least 80 feet below ground. A deeper sand and gravel unit is the primary source of drinking water in the region. There are several small lakes and ponds on and near the property.

General Motors Customer Care and Aftersales Facility Map

Recent Accomplishments

  • In 2021, EPA requested GM to do additional rounds of PFAS sampling. Samples were collected in February, August, and November of that year.
  • In December 2021, GM submitted a report with the results to EPA. The highest results were: 37 ppt PFOS, 220 ppt PFOA, and 55 ppt PFNA.
  • On February 23, 2022, EPA presented the site and proposed remedy to EGLE.

Next Steps

  • EPA will coordinate with EGLE to request additional information from GM and determine next steps.

Residential Well Sampling / Alternative Water Information

  • Most residents in the area are on private drinking water wells that are down deeper than where the known PFAS contamination has been detected. EPA and GM are currently evaluating the extent of the PFAS contamination and will determine if residential wells should be sampled.

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

August 2020 – November 2021

31

14

* 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 at this time.