120th Avenue Area (Robinson Township, Ottawa County)

*This site was previously listed as an "Area of Interest" on the MPART website since it did not have a groundwater sample result over 70 ppt PFOS+PFOA; once a result over that criteria was returned, this area is now an official MPART site.

This is an area located approximately one mile north of M-45 (Lake Michigan Drive) on 120th Avenue. In September 2018, an elementary school in the area, Robinson Elementary, had their drinking water well tested by EGLE as part of the statewide sampling initiative. The results from this well were 110 ppt PFOS+PFOA, which is over the USEPA’s LHA level of 70 ppt PFOS+PFOA.  This prompted a public health response from the State of Michigan. A source investigation began immediately in this area, which includes the Robinson Township Fire Department.

Robinson Elementary is near a groundwater divide, which means groundwater flows in different directions. Regional groundwater generally flows north along 120th Avenue towards Little Robinson Creek, a tributary that flows northwest to the Grand River. On the south side of the school, the direction of groundwater flow is to the south towards county drains and natural tributaries of the Bass River which flow east and discharge to the Grand River. Certain high-volume irrigation wells in the area have some impact on the direction of groundwater flow during the growing season but revert to natural flow for the rest of the year.

• On September 18, 2018, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) collected a sample from the drinking water well at Robinson Elementary School as part of the statewide sampling initiative.
• On October 29, 2018, EGLE received the results from the September 2018 testing. Results showed 110 ppt PFOS+PFOA in the drinking water, which is over the USEPA’s LHA level of 70 ppt PFOS+PFOA. The results also showed 144 ppt Total Tested PFAS. This prompted a public health response from the State of Michigan. A source investigation began immediately, including two phases of residential well sampling and a preliminary hydrogeological investigation.
• On October 29, 2018, EGLE collected a sample at a daycare adjacent to the school.
• On November 2 – 5, 2018, as part of Phase I sampling, EGLE collected 23 residential well samples, as well as a sample from Robinson Elementary’ s irrigation well, Robinson Township Park’s irrigation well, an adjacent daycare, the township hall and fire department, a church, and the wellhead at the school (to rule out internal plumbing as a potential source).
• On November 27, 2018, EGLE received all results from the Phase I sampling, which are shown below:
   

The two samples that exceeded the USEPA LHA of 70 ppt PFOS+PFOA were a residence and the irrigation well at Robinson Elementary. The adjacent daycare was sampled twice. Results are shown below:

• On November 30, 2018, as part of Phase II sampling, EGLE collected 37 residential well samples. Results were:
   

• On February 20, 2019, EGLE began a hydrogeological study to understand the vertical and horizontal extent of impact and better understand where the source area is potentially located.  The hydrogeological investigation included the installation of monitoring wells at the Robinson Elementary School, the Robinson Township Park, the Robinson Township Fire Station, as well as two residential properties adjacent to the Fire Station, sampling of the vertical aquifer, and soil sampling. Beginning February 20, 2019 and ending on March 1, 2019, EGLE collected 24 groundwater samples from the 120th Avenue PFAS Study Area. PFAS was also detected in groundwater at Robinson Elementary School with 61 ppt PFOS+PFOA and 409 ppt Total Tested PFAS. 
• Between March 12, and April 2, 2019, EGLE received the results from the February and March groundwater sampling. The highest result was 643.61 ppt PFOS+PFOA and 2,142.27 ppt Total Tested PFAS.
• The hydrogeologic investigation did not identify a definitive source of PFAS contamination in the area. The presence of PFAS compounds in soil samples and the elevated concentrations of PFAS in groundwater at Robinson Elementary School and the Robinson Township Fire Department indicate the PFAS compounds may have been released at both locations. EGLE explored whether this could have been caused by the use of Aqueous Film Forming Foam (AFFF or Class B Fire Fighting Foam). However, the Robinson Township Fire Department indicated AFFF is not currently possessed nor historically used, and the Fire Department does not have any historical knowledge of AFFF being applied in the area. An investigation by EGLE confirmed the foam currently used by the Robinson Township Fire Department does not contain PFAS. AFFF has been available since the 1960’s, and it is possible that it was applied in the area during an era that pre-dates the knowledge of anyone currently associated with the Fire Department. No other potential sources such as illicit dumping or disposal of industrial waste have been identified.
• On November 12, 2019, EGLE began a second phase of hydrogeological investigation to better delineate the extent of groundwater impact to the north and east of the Robinson Township Fire Station.  The investigation includes 12 additional vertical aquifer sampling (VAS) boreholes located along an east-west transect approximately 0.25 miles to the north and 0.25 miles to the east of the fire station.  Temporary shallow monitoring wells were installed to allow us to more accurately understand how water withdrawals for both agricultural usage and residential usage might impact the groundwater flow direction.  EGLE is currently evaluating the lab results generated during this sampling event.  None of the groundwater samples collected during the second phase of hydrogeological investigation exceed 70 ppt for PFOS+PFOA.  Results are indicated on the sampling chart.
• In December 2019, an ion-exchange (I-EX) PFAS treatment system was installed in the Robinson Elementary Building.  The system could not be connected to the existing pump and well, because the existing pump may not be capable of providing water to the building as well as provide sufficient drinking water through the treatment system for the building.  Attempts were made to replace the pump with a larger pump.  The school is exploring options to replace the existing well with a new higher capacity pump and well, potentially located in a less impacted area of the shallow aquifer.

  Sampling Results Summary: PFOS and PFOA Only

  Type of Sample	Date Sampled (or Range)	Numberof Samples	Number of Results Received	Number of Non-Detects	Number Between Non-detect and Standard*	Number Greater Than or Equal to Standard
  Monitoring Wells	Multiple	61	61	18	40	3
  Residential Drinking Wells	Multiple	61	61	32	28	1
  Private Non-Residential Water	Multiple	11	11	1	6	4
  Cumulative		133	133	54	74	8

  *Groundwater results are compared to EGLE Part 201 Criteria of 70 ppt PFOS+PFOA.

  *Residential well results are compared to the USEPA Lifetime Health Advisory level of 70 ppt PFOS+PFOA.

  Sampling Notes

  • Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.
  • On March 17, 2019, EGLE has collected four soil samples; the highest result was 19,500 ppt PFOS+PFOA and 28,800 ppt Total Tested PFAS.