State Disposal Superfund Site (Plainfield Township, Kent County)

• In 2016 as part of a USEPA municipal water supply testing initiative, PFAS was detected in Plainfield Township's municipal water.
• Most residents in the area are connected to the Plainfield Township municipal water supply system; however, staff from EGLE identified 31 private residential wells adjacent to the contaminated groundwater plume from the State Disposal Landfill, Inc.
  • During 2017 and 2018, WMMI, owner and operator of this site, collected 20 groundwater samples from private residential wells at 18 properties east and south of the landfill. One sample east of the landfill had 26 ppt PFOA.
  • EGLE sampled 11 additional residential wells east of the landfill. Two wells were under 10 ppt PFOS+PFOA; the remainder of the wells were non-detect. The possibility of other source areas separate from the State Disposal Landfill is being investigated.
  • Of the residential wells sampled to date, 45 wells are non-detect and none are in exceedance of 70 ppt combined concentrations of PFOS and PFOA.
• In April 2018, WMMI installed five new vertical profile soil borings (the original monitoring wells were installed back in the 1970's) to assist in determining the source of the contamination and potential impacts on surface water. EGLE staff may install additional groundwater monitoring wells to address possible data gaps.
  • PFAS concentrations above 70 ppt were present in groundwater migrating from the State Disposal Superfund Site.
  • PFAS was detected in the industrial pretreatment sampling for the State Disposal Superfund Site performed by EGLE WRD.
• On December 11, 2018, WMMI installed an additional vertical aquifer sample boring to assist evaluation of PFAS in groundwater coming from the State Disposal Superfund Site. On that same day, EGLE staff observed a portion of the drilling activities performed by WMMI contractors.
• EGLE is requesting WMMI perform additional hydrogeological investigation to evaluate groundwater contaminants from the State Disposal Landfill migrating near the Plainfield Versluis Wellfield.

• On February 20, 2019, EGLE staff met with WMMI and discussed recent sampling activities.
• On April 1, 2019, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) staff received the 2018 Annual Environmental Monitoring Report. On August 9, 2019, EGLE sent WMMI a formal letter requesting that WMMI perform additional hydrogeological investigation to delineate groundwater contaminants from State Disposal Landfill migrating near the Plainfield Versluis Wellfield.
• On August 9, 2019, EGLE requested that WMMI perform additional hydrogeological investigation to delineate groundwater contaminants from State Disposal Landfill migrating near the Plainfield Versluis Wellfield.
• On September 23, 2019, EGLE met with WMMI to discuss EGLE's recommendations for further investigation at the site.
• On October 28, 2019, WMMI conducted semiannual groundwater sampling at the State Disposal Landfill. A total of 22 groundwater samples were taken from 20 locations. On January 9, 2020, EGLE reviewed the sample results collected in October 2019.  The highest PFOS + PFOA sample result was 1,110 ppt and the highest total PFAS was 2,652 ppt.  All sample results are reflected on the sampling chart.

• On March 31, 2020, EGLE received from WMMI a revised 2020 Groundwater Monitoring Plan and the 2019 Annual Environmental Monitoring Report. EGLE reviewed these documents and provided comments to WMMI on June 23, 2020.
• On May 21, 2020, EGLE sent a formal notice letter to WMMI stating EGLE's intent to use State funds to undertake required response activities as described in a work plan developed for EGLE by AECOM.  
• On June 12, 2020, WMMI proposed an alternative work plan.  WMMI Work Plan makes significant efforts to address data gaps regarding delineation of groundwater contaminants migrating from the Site

Historical Sampling Chart: Data is reflective of criteria prior to August 3, 2020,  PFOS and PFOA Only

This chart reflects data received prior to August 3, 2020.

• On March 31, 2021, WMMI submitted to EGLE the 2020 Annual Environmental Report for the Site. On May 4, 2021, EGLE staff completed its review of the Report and provided comments to WMMI.
• On October 19, 2020, WMMI began implementing the Groundwater Investigation Work Plan at the Site to install vertical aquifer borings and to conduct groundwater/surface water sampling. On July 9^, 2021, WMMI submitted to EGLE a Technical Memorandum which summarized the additional site investigation activities. EGLE staff reviewed the information and provide recommendations to WMMI on October 7, 2021. Additional investigations activities are under discussion.
• While the additional investigation conducted by WMMI makes significant efforts to address data gaps regarding delineation of groundwater contaminants migrating from the Site, EGLE has identified necessary response activities that have not been included in the WMMI’s scope of work.
• Beginning on March 22, 2021, EGLE proceeded with implementation of the response activities that WMMI chooses not to perform to complete groundwater investigation objectives. This included vertical aquifer profile sampling at one location on the southern edge of Versluis Lake.
• In May 2021, EGLE reviewed the results and provide the data to WMMI. Of the ten groundwater samples, nine samples exceeded the Part 201 Drinking Water Criteria for PFOA. None of the samples exceeded Groundwater Surface Water Criteria. Based on the data, EGLE installed one permanent monitoring well to better monitor PFAS and 1,4-Dioxane in the groundwater.
• On July 8, 2021, WMMI submitted a final write-up of this work in a report titled, the Technical Memorandum Submittal for Supplemental Groundwater and Additional Sampling. EGLE staff have completed their review of this document and provided recommendations to WMMI for additional investigation activities. EGLE staff continue to discuss with WMMI next steps.

Sampling Results Summary

This table reflects data received after August 3, 2020.  Data prior to August 3, 2020 is reflected in the timeline below. This table was updated to include all seven PFAS criteria effective December 21, 2020.

* 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).
* Surface water samples are compared to Rule 57 non-drinking water values of 12 ppt for PFOS and 12,000 ppt for PFOA.

Sampling Notes

• On August 3, 2020, new Part 201 Criteria went into effect.  Historical sampling data compared to Part 201 Criteria >70 is captured in the historical timeline below.
• Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.