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Grantee Research Project Results

Final Report: Phytoremediation of perfluoroalkyl substances (PFAS) via phytoextraction

EPA Contract Number: 68HE0D18C0018
Title: Phytoremediation of perfluoroalkyl substances (PFAS) via phytoextraction
Investigators: Huff, David , Morris, Larry , Nutter, Wade
Small Business: Nutter & Associates, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: October 1, 2018 through March 31, 2019
Project Amount: $99,583
RFA: Small Business Innovation Research (SBIR) - Phase I (2018) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Land Revitalization

Description:

Nutter & Associates, Inc. of Athens, Georgia implemented a study to screen and identify plant species that show promise for Proof-of-Concept testing for phytoremediation of PFAS via phytoextraction. Phytoremediation is the direct use of living plants for in situ remediation of contaminated soil, sludges, sediments, and shallow groundwater through contaminant removal, degradation, or containment. Phytoextraction, also called phytoaccumulation, refers to the uptake and translocation of contaminants in the soil by plant roots into the aboveground portions of the plants. The goal of our Phase I study was to achieve Proof-of-Concept for one or more plant species via a bench trail investigation leading to the development of an effective phytoremediation process and methodology for the cleanup of PFAS in soil and sediment by:

  • Selecting promising plant species from our research and experience dealing with sites where soil and sediments are impacted by PFOS and PFAS (e.g., land treatment sites);
  •  Growing live plant species selected from our research in a soil environment containing known quantities of PFOA or PFOS; and
  •  Removing a significant portion of the PFOS/PFOA compounds from the soil through phytoextraction and harvesting the above-ground plant tissue.

In assessing the fitness of plant species to serve in a phytoremediation role by means of phytoextraction the Bioconcentration Factor (BCF) is a key metric. The BCF is calculated as the plant/soil contaminant concentration ratio: BCFplant  = Cplant/Creference media

Summary/Accomplishments (Outputs/Outcomes):

Based on the project findings and laboratory data, the phytoremediation study demonstrated hyperaccumulation of multiple PFAS compounds, exhibiting a greater than 10-fold soil to leaf translocation of PFAS compounds in above-ground plant tissue. The BCFs of the hyperaccumulating species with respect to PFOA ranged from 11.5 to 46.5 and included four herbaceous and four woody species. The BCFs of the hyperaccumulating species with respect to PFOS ranged from 10.3 to 17.9 and included one herbaceous and three woody species. With respect to the woody species, hyperaccumulation was observed in the leaves and petioles but not in the woody mass (mainstems and branches).

Additionally, a separate component of the study showed that higher plant accumulation of PFOA and PFOS, ranging from 44 to 344 percent, was achieved when a proprietary soil amendment was applied. Hyperaccumulation of PFOS in the tree species leaves and petioles was only observed when the soil amendment was applied.

Conclusions:

The project results establish Proof-of-Concept for the viability of phytoextraction as a means of remediating PFAS-impacted soil, sediment, and potentially shallow groundwater.

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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