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Mechanochemical Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foams and Contaminated Soil
Citation:
Gobindlal, K., E. Shields, A. Whitehill, C. Weber, AND J. Sperry. Mechanochemical Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foams and Contaminated Soil. Environmental Science & Technology Letters. American Chemical Society, Washington, DC, , NA, (2023). https://doi.org/10.1039/D3VA00099K
Impact/Purpose:
Per- and polyfluoroalkyl substances (PFAS) are stable and persistent pollutants in the environment. The use of aqueous film forming foams (AFFF) has led to PFAS contaminated soils around the sites where AFFF was used to extinguish fires and for fire fighting training. PFAS can enter the drinking water near these sites, exposing people to PFAS. Some PFAS found in some AFFFs can have negative health effects in humans. To ensure human and animal health, it is important to find methods to treat PFAS contaminated soil effectively remove and destroy the PFAS. Here mechanochemical destruction (MCD) is investigated as a potential method to destroy the PFAS in soil and also as a method to destroy the AFFF concentrates themselves. MCD does not require solvents or elevated temperatures and has been used to treat soils with other persistent organic pollutants using only quartz sand as an additive. This benchtop study shows that MCD has promise as a method to destroy PFAS in soils and concentrated liquids. The quantifiable PFAS in the samples were no longer detected by the end of the treatment with both matrices. No fluorinated organic byproducts were found in the solids as well. These results show that full-scale MCD could be an option for communities, states, regions, or other agencies to remediate PFAS contaminated soil and also to potentially destroy their stockpiled AFFF.
Description:
Per- and polyfluoroalkyl substances (PFASs) are a class of synthetic chemicals of concern that exhibit extreme persistence within the environment and physicochemical properties that are resistant to targeted degradation. Comprising substantial concentrations of PFASs, aqueous film-forming foams (AFFFs) present a major exposure pathway to the environment having been applied to land at firefighting-training sites globally for decades. This has led to significant contamination of environmental media, which has in-turn negatively impacted the health of communities within the vicinity of these facilities. Herein, we demonstrate that mechanochemical destruction (MCD) is an effective method for destruction of PFASs in an AFFF concentrate and an authentic sample of PFAS-contaminated soil derived from a decommissioned firefighting training facility. Destruction efficiencies ranged from 99.88% to 100%. The only additive used for the MCD treatment was quartz sand, which was used for the liquid AFFF sample, with no additives required for the destruction of PFAS in the contaminated soil. This confirms the viability of MCD for both the remediation of PFAS-contaminated land and the destruction of stockpiled AFFFs.
URLs/Downloads:
DOI: Mechanochemical Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foams and Contaminated Soil