At the Full Wolverine Community Advisory Group Meeting on March 18th, the CAG Technical Committee presented their discussion of the House Street Feasibility Study Cleanup. This is a summary of that presentation. The original presentation slides can be found here.
The Feasibility Study (FS) evaluates different remedy options to both manage the solid wastes and PFAS leakage into the groundwater.
Wolverine is proposing to use phytoremediation and a small cap (“phyto-cap”) to remedy the House Street Disposal Site. Phytoremediation is a process that uses various types of plants to remove, transfer, stabilize, and/or degrade contaminants in the soil and groundwater. The EPA states that phytoremediation is best suited for large areas of 0-3 feet contamination, or large volumes of water with low-level contamination. The main disadvantages of phytoremediation are the long timeline, the limitations on the depth of the contamination, and the possibility of contaminating plant material that animals can consume. Most pointedly, a study included in the FS dated May 29, 2018 shows that PFAS waste at House Street are buried 3-20 feet deep. Based on these criteria, phytoremediation is not appropriate for House Street because of its high levels of deep contamination in the soil and groundwater and high potential for wildlife exposure.
The consultant hired by Wolverine Worldwide to complete the FS, GZA, makes numerous statements that phytoremediation will reduce and/or control infiltration. However, studies highlighted by this presentation demonstrate that this may not be appropriate for the House Street site. Given that the site is heavily wooded, there may be minimal difference between current infiltration in the existing forest versus tearing out live, mature trees and planting new ones. GZA’s literature citations used to support their claims have limited relevance to the use of phytoremediation at House Street, and the Technical Committee states that “remedial solutions with this timeline are unacceptable unless a pilot study or other relevant data are presented showing better performance.”
Because phyto-cap allows continued infiltration and leaching, other alternative options are described. A cap remedy option manages waste by covering the surface material with an impermeable barrier to limit leaching and infiltration to groundwater. Pump and treat remedies manage contamination at the source and reduce groundwater migration.
Thank you to Dr. Richard R. Rediske and the CAG Technical Committee for preparing this presentation. To read more about the study, additional site documents on House Street Site are available here. Feasibility Study comments were due April 17th. The CAG submitted formal comments to EGLE regarding the House Street Feasibility Study on April 16, 2021, which can be found here.