On Friday, August 6, Tyco submitted to the Wisconsin Department of Natural Resources (DNR) an annual report about testing in the Private Well Sampling Area (PWSA) where some drinking water wells have been impacted by PFAS from historic operations at Tyco’s Fire Technology Center (FTC).
The report includes the results of the most recent sampling events that included analysis of 36 PFAS compounds. In all, over 75% of wells remained below PFAS standards recommended by the Wisconsin Department of Health. Over 50% of wells continued to show no detections above the laboratory reporting limit.
The report further confirms previously reported analyses and conclusions concerning the FTC PFAS plume and test results are as expected. Most wells tested show no change, some show decreases in concentration; others some increase. This slight variability is expected and is primarily due to a minor redistribution of mass within the plume associated with continued groundwater pumping at each private drinking water well and ongoing contributions of PFAS from septic systems at each house in the PWSA.. The boundaries of the plume and Tyco’s PWSA remain the same with no wells being added or deleted based on these latest PFAS sampling results. In short this is a mature, established plume.
Geology, Gravity and History Establish the Boundaries of the Plume:
- Groundwater flows via gravity. Therefore, it generally moves from higher elevations to lower elevations. The area is underlain by sand and bedrock with groundwater containing PFAS flowing generally eastward through the sands toward Ditch B. Groundwater flow to the west is restricted by shallow bedrock and gravity since water does not travel “uphill.”
- The groundwater plume is mature and defined. Outdoor testing of AFFF fire-fighting foam with PFAS began in the 1960s, and the age of the plume is similar to the age of outdoor testing at the FTC. Groundwater patterns have been uniform for a long time. It is a mature plume, and its boundaries are as defined within the PWSA.
It is important to note that when the Groundwater Extraction Treatment System (GETS) that Tyco is constructing with its environmental consultants is operational, it will hydraulically contain the plume – meaning PFAS migrating from the FTC will be captured and treated prior to reaching Ditch B. GETS construction begins this month, and the system is scheduled to be in full operation by early next year.
To access the report submitted to the Wisconsin Department of Natural Resources, please visit: http://bit.ly/TycoWisconsinDNR, scroll down to 2021-08-06 and the file named “POTABLE WELL LONG TERM MONITORING RESULTS THROUGH MARCH 2021”