The objective of this project is to demonstrate the technical viability of the phytoremediation methodology for matrices impacted with per- and polyfluoroalkyl substances (PFAS) via a grow house based investigation founded on the previous examination using real-world PFAS-impacted soils. Specific deliverables associated with the investigation will include a performance report that will satisfy key objectives:

1. Confirm whether the previously identified highest perfluorooctane sulfonate (PFOS)-accumulating plant species shows adequate PFOS accumulation when grow house testing is conducted using actual soils collected from impacted sites,
2. Determine whether specific soil amendment methodologies show statistical significance to improve PFOS accumulation, and
3. Estimate remedial time frames versus PFOS concentration based on the achieved accumulation rates.

These deliverables will facilitate the initial evaluation of phytoextraction as a viable corrective action alternative for PFOS-impacted soil and inform decisions to further develop the technology.

Phytoextraction of PFAS from Soil and Groundwater

Phytoextraction, also called phytoaccumulation, is the uptake and translocation of chemicals in the soil by plant roots into the aboveground portions of the plants. Based on the favorable results of a previous investigation that established the proof of concept, a phytoremediation investigation will be conducted to demonstrate the viability of the phytoextraction methodology for PFAS-impacted sites by conducting the second grow house investigation using the most effective PFOS accumulating plant species grown in PFOS-impacted soils acquired from up to five sites employing a statistics-based randomized block design. Successful accumulation during the investigation will be defined by achieving PFOS shoot to soil (or shoot + thatch to soil) concentration ratios that are >1 and that show extrapolated PFOS accumulation rates meeting one-half reduction of the root-zone soil concentrations of PFOS within a 10-year time horizon.

There is a salient need to develop viable remediation options for PFAS-impacted soils and shallow aquifer formations. The phytoremediation methodology is expected to be highly cost competitive, particularly at larger impacted sites (e.g., two acres and greater) with moderate to low levels of PFAS. Phytoremediation application cost are estimated to be typically 50 to 80 percent lower than other remedial alternatives. Hence, where phytoremediation technology is applicable (e.g., moderate to large impacted sites is within the zone), the approach can be a cost competitive, effective, and sustainable remedial option, ultimating contributing to ensuring the long-term sustainability of DoD installations and essential operations. (Anticipated Project Completion - 2026)