PFAS Cleanup
Introduction
Click the PFAS button to learn how PFAS gets into the environment, and to see maps of where PFAS pollution has been found.
Soil Remediation
Some of the methods used to remove PFAS from soil, are also useful for getting PFAS out of water. Specifically using wetland plants we can help remove PFAS as it moves through wet environments, or before it can wash out of soil and into our water supplies.
"Currently, the standard approach to PFAS cleanup involves excavating the affected soil. The costs can be astronomical: One estimate for the contaminated soil on a 100-acre dairy farm in Maine ran upward of $25 million. Using plants, Huff said, can cost 75 percent less at least. That’s not to say plant-based PFAS removal comes cheap exactly: Soil testing can cost anywhere from $250 to $600 per sample. And for any given field, samples at multiple points across the field are needed to measure progress, especially as PFAS levels can vary from spot to spot within the same parcel of land.
Huff, who has studied various grasses and trees’ ability to extract PFAS, said plants work best when the contaminant levels are lower and the cleanup area is larger — around two acres or more. By that measure, most farms would be considered large projects.
And size isn’t the only limitation — phytoremediation takes more time compared to other approaches." - https://grist.org/science/pfas-is-contaminating-farms-can-hemp-help/
Excavation
Faster, more costly, and still requires a new place for the contaminated materials to be moved to.
Soil washing
Detaching PFAS from the soil by washing with water. Requires low technology and land reuse could be possible. On the downside it is expensive and time-consuming, still resulting in contaminated water.
Bioremediation
Pseudomonas (a genus of Gram-negative, Gammaproteobacteria)
"Indigenous bacterial species isolated from PFAS-contaminated environments have shown the ability to remediate PFAS compounds; two strains of Pseudomonas (PS27 and PDMF10) were able to remove 32 and 28% of PFAS compounds, respectively, within 10 days of incubation under alkanotrophic conditions (Presentato et al., 2020). Further, a decrease of around 32% in PFAS was also reported during a 96 h incubation of Pseudomonas parafulva (Yi et al., 2016) along with a 67% decrease in PFAS concentration over 48 h incubation of Pseudomonas aeruginosa (Kwon et al., 2014). In another study, Pseudomonas plecoglossicida utilized PFAS as an energy source, producing perfluoroheptanoic acid and releasing fluorine ions as a result (Chetverikov et al., 2017). A recent publication reported that following incubation of the ammonium oxidizing bacterium, Acidimicrobium sp. strain A6 with hydrogen as the sole electron donor for 100 days a 60% reduction in PFAS concentration was observed..."
Below are the reported abilities of promising microorganisms currently under investigation:
Pseudomonas sp. strain PS27 removes 32% of 200 ng L−1 PFAS concentration over 10 days via aerobic bioaccumulation.
Pseudomonas sp. strain PDMF10 removes 28% of 200 ng L−1 PFAS concentration over 10 days via aerobic bioaccumulation.
Pseudomonas parafulva removes 32% of 500 mg L−1 PFAS concentration over 96 hours via aerobic bioaccumulation.
Pseudomonas aeruginosa strain HJ4 removes 67% of 1,400–1,800 μg L−1 PFAS concentration over 48 hours via aerobic bioaccumulation.
Pseudomonas plecoglossicida 2.4-D removes 75% of 1 g L−1 PFAS concentration over 6 days via aerobic bioaccumulation.
Acidimicrobium sp. strain A6 removes 60% of 100 mg L−1 PFAS concentration over 100 days via defluorination/ biodegradation.
Gordonia sp. strain NB4-1Y removes 70% of (nondetermined? PFAS concentrations)over 10 days in Sulfur-limiting conditions via biodegradation.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7817812/
Mycoremediation
(This section is edited to include additional links in text which were not part of the original paragraph.)
"White-rot fungi in particular have displayed relative success in terms of the biotransformation of organic toxicants, including polychlorinated biphenyls, organophosphate pesticides and polycyclic aromatic hydrocarbons (Kaur et al., 2016; Stella et al., 2017; Harry-Asobara and Kamei, 2019). There are very few studies examining their ability to degrade PFAS. Tseng et al. (2014) reported some promising preliminary results looking at the effects of wood-rotting fungus on 6:2 FTOH, using the ligninolytic fungi, Phanerochaete chrysosporium. P. chrysosporium was capable of transforming 50% of 6:2 FTOH and 70% 8:2 FTOH in 28 days. Major metabolites of 6:2 FTOH included 5:3 polyfluorinated acid (40%), 5:2 FTOH (10%), PFHxA (4%). In contrast, the non-lignolytic fungus Aspergillus niger was unable to transform 6:2 FTOH over 35 days. while the same study reported that P. chrysosporium was capable of transforming 20% PFOS within 28 days. However, this research was conducted in a laboratory; it remains to be determined whether ligninolytic fungi are capable of degrading PFAS in the environment."
Phytoremediation
This is the use of plants to absorb dangerous materials including heavy metals and PFAS. Where land is polluted, the ground water generally is to, which may put restrictions on water use, meaning plants watered and intended to remove PFAS may require water to be shipped in from elsewhere.
"Future studies will also need to develop guidelines for how people should dispose of the PFAS-laden plants once their job is done. That could entail drying first to reduce the sheer mass", Huff said. "The key is safely discarding waste to avoid creating another mess." - https://grist.org/science/pfas-is-contaminating-farms-can-hemp-help/
Hemp
"Hemp is a good candidate for phytoremediation because it grows fast across much of the United States. Its roots are deep and profuse — the better to uptake pollutants from soil." However "It’s still unclear how much of the chemicals hemp can remove. Although the Loring project successfully extracted some PFAS, plenty remained in the soil. Also unclear is how many rounds of hemp planting it would take to return levels to a “safe” baseline — something that doesn’t technically exist yet without national standards from the EPA." - https://grist.org/science/pfas-is-contaminating-farms-can-hemp-help/
Wetland Pants
This paper explains that "Phytoremediation of PFAS is a possibility and both PFOA and PFOS can be taken up by plants from soil [9] and from hydroponic cultures [10]. There were measurable contents of PFOS and PFOA in the vegetative parts of the plants also after treatment in very low levels of PFOA and PFOS in the medium. More of these substances was found in roots than in shoots [5]. Pilot studies with wetland plants showed that roots of four different aquatic plants species absorbed PFOS and PFOA from water [11]. Up to 82 and 95 % of PFOA and PFOS, respectively, were removed from the water 15 days after treatment. Authors claimed that phytoremediation and soil sorption were the best methods to remediate PFAS. Recently, Wang et al. [12] claimed that submerged plants had higher bioaccumulation factor of PFOS and PFOA than emergent plants collected from a wetland with PFAS polluted water.
Treatment of PFAS contaminated water using plants will decrease PFAS in the water and there are various possible ways it can be performed. Plants may excrete enzymes or promote microbial production of enzymes that degrade PFAS in the water. They can remove PFAS or the degraded PFAS compounds from the water by uptake. In the tissue, PFAS or the degraded compounds will either be accumulated or degraded by the use of cellular or extra cellular enzymes. Both laccase and peroxidase were shown to degrade PFOA [13,14], and those enzymes were produced in the plants and were used in cell wall polymerization and lignin synthesis [15]. These enzymes can be found in the rhizosphere [16]."
The study tested the following plants which have been listed below from most to least effective according to the test results.
Click the photos to learn more about each species. Check to make sure plants are native before planting them, or you make introduce invasives.
Bottle sedge (Carex rostrata) an emergent plant species "In the third experiment, C. rostrata showed higher removal than E. angustifolium; 42 % PFOA and 64 % PFOS was removed by C. rostrata after 12 days of the treatment (Table 2). Compared with E. angustifolium in the second experiment, 4 times more PFOS and 3 times more PFOA was removed despite 2.6 times more roots and 2 days shorter removal period."
Common cotton grass (Europhorum angustifolium) an emergent plant species which 'removed about 13% and 17% of PFOA and PFOS, respectively, even with less root biomass than S. viminalis.' and "In the second experiment, E. angustifolium removed 13% PFOA and 22% PFOS after 14 days similarly as in the first experiment (Table 2). The other detected PFAS analyzed, (PFAB, PFPeA, PFHxA, PFHpA, PFBS) was also removed from the water, between 5-14% by E. angustifolium (Table 1)."
Canadian pondweed (Elodea canadensis) a submergent plant species "In the fourth experiment C. rostrata and E. canadensis was tested for removal efficiency. After 3 days treatment C. rostrata removed 9 % PFOA and 13% PFOS while E. canadensis removed 14 % PFOA and 19 % PFOS (Table 2). Both plants removed similarly (Figure 1, Table 2), and the removal was related to their submerged biomass (Table 2). Significant removal rate for PFOS and PFOA was observed in both the plants after one day; which gradually increased with time (Figure 1). For C. rostrata, removal rate was faster for PFOS as compared to PFOA and it remained linear for nearly 12 days. The same was shown for E. Canadensis during the 3 days experiment."
Common rush or soft rush (Juncus effusus) accumulated 11.4% of seven PFAS compounds from PFAS-spiked soil...
Birch trees (Betula pendula) were reported to accumulate up to 97 ng g−1 during a study at a firefighting training site near Stockholm, Sweden, contaminated with 26 PFAS compounds
Spruce trees (Picea abies) were reported to accumulate up to 94 ng g−1 during a study at a firefighting training site near Stockholm, Sweden, contaminated with 26 PFAS compounds
Willow (Salix viminalis) a terrestrial plant species "The first experiment with terrestrial and emergent plants, S. viminalis and E. angustifolium, showed that within 14 days S. viminalis did not significantly remove any PFOS or PFOA from the water (Table 2)"
Enzymes
So far the information I've found on this subject seems to suggest this as a secondary step after phytoremediation, as a method to break down the chemicals absorbed by the plants, splitting the PFAS into fluorine gas and carbon dioxide which could be used as an industrial ingredient. Studies on this topic are ongoing with organizations including the University of Virginia.
Blood & Plasma Donations
Studies have found that "Regular Blood Donations Have a Strange Hidden Benefit We Never Knew About".
"The researchers tested 285 firefighters working at the Fire Rescue Victoria service in Australia, who donated both blood and plasma over the course of 12 months. Firefighters are routinely exposed to PFAS via firefighting foam, and typically have higher levels in their blood than the general population. "The results from the study show both regular blood or plasma donations resulted in a significant reduction in blood PFAS levels, compared to the control group," says haematologist Robin Gasiorowski, from Macquarie University in Australia.
Grants & Funding
North America
USA
Minnesota
Capital Project Grants "are designed to support final engineering and construction of large-scale, innovative projects that protect or improve water quality and habitat within the MWMO watershed. The MWMO provides both technical and financial assistance to eligible projects. (Smaller-scale projects may be eligible for a Stewardship Fund Grant.)"