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ARS Home » Pacific West Area » Riverside, California » Agricultural Water Efficiency and Salinity Research Unit » Research » Publications at this Location » Publication #412229
Research Project: Protection of Food and Water Supplies from Pathogens and Human Induced Chemicals of Emerging Concern

Location: Agricultural Water Efficiency and Salinity Research Unit

Title: Biochar as a strategy for PFAS remediation in agricultural contexts: A review

Author
item Ramos, Maria
item Ashworth, Daniel

Submitted to: Critical Reviews in Environmental Science Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2024
Publication Date: 4/5/2024
Citation: Ramos, M.P., Ashworth, D.J. 2024. Biochar as a strategy for PFAS remediation in agricultural contexts: A review. Critical Reviews in Environmental Science Technology. 927:172275. https://doi.org/10.1016/j.scitotenv.2024.172275.
DOI: https://doi.org/10.1016/j.scitotenv.2024.172275

Interpretive Summary: Per- and polyfluoroalkyl substances (PFAS) are a family of compounds that are ubiquitous in the environment due to their historic widespread use in commercial and industrial products. There is growing concern over the presence of PFAS in agricultural compartments (e.g., soil, water, plants, soil fauna) due to their detrimental effects on environmental and human health. This has led to an increased interest in scalable technologies that can be feasibly used to clean up the environment. One such strategy involves using biochar to remove PFAS via adsorption. Biochar is a carbon rich material that can be produced from different agricultural waste materials such as crops, wood, grasses, and manure. This review summarizes sources of PFAS in agriculture as well as the risks of their accumulation in crops and in soil fauna/microbiomes. The relationship between the physicochemical properties of biochar and its ability to remove PFAS was assessed by performing statistical analyses of the data presented in the available literature. The main biochar-based PFAS treatment strategies (water filtration, soil application, mixing with biosolids) were also reviewed to highlight the benefits and complications of each. Finally, the economic and environmental impacts of using biochar as a strategy to remove PFAS from agricultural compartments was evaluated by using data from the literature to calculate the energy demand and global warming potential associated with these processes. This review identifies key gaps in our knowledge of (i) PFAS removal by biochars in agricultural remediation applications and (ii) environmental costs/benefits of biochars in relation to their removal properties toward PFAS. The concepts introduced in this review may assist in developing large-scale biochar-based PFAS remediation strategies to help protect the agricultural food production environment.

Technical Abstract: Growing concern over the presence of per- and polyfluoroalkyl substances (PFAS) in agricultural compartments (e.g., soil, water, plants, soil fauna) has led to an increased interest in scalable and economically feasible remediation technologies. Biochar is the product of pyrolyzing organic materials (crop waste, wood waste, manures, grasses) and has been used as a low-cost adsorbent to remove contaminants including PFAS. This review summarizes sources of PFAS in agriculture as well as the risks of their accumulation in crops, and soil fauna/microbiomes. A review of the available literature facilitated framing biochar as a strategy for mitigating detrimental environmental impact of PFAS on agriculture. The effects of biochar physiochemical properties on the removal of PFAS from water were evaluated using principal component analysis following evaluation of more than 100 data points from the available literature. The main biochar-based PFAS treatment strategies (water filtration, soil application, mixing with biosolids) were also reviewed to highlight the benefits and complications of each. Life cycle analyses on the use of biochar for contaminant removal were summarized, and data from selected studies were used to calculate (for the first time) the global warming potential and net energy demand of various agriculturally-important biochar classes (crop wastes, wood wastes, manures) in relation to their PFAS adsorption performance. This review serves to identify key gaps in our knowledge of (i) PFAS adsorption by biochars in agricultural remediation applications and (ii) environmental costs/benefits of biochars in relation to their adsorptive properties toward PFAS. The concepts introduced in this review may assist in developing large-scale biochar-based PFAS remediation strategies to help protect the agricultural food production environment.