High Carbon Wood Ash Impact on Grass Uptake of Per- and Polyfluoroalkyl Substances from Contaminated Agricultural Soils

In a one-year greenhouse study, a low-cost high-carbon wood ash was mixed at 1.5, 3.0, and 6.0 wt % into a per- and polyfluoroalkyl substance (PFAS)-contaminated farm soil to evaluate PFAS uptake into perennial forage grasses across five harvest cycle. Wood ash significantly reduced (<i>p</i> <0.05) grass uptake of several short- and long-chain PFASs. For the highly bioaccumulating perfluorooctanesulfonate, grass leaves from the 6 wt % wood ash treatment exhibited markedly lower translocation factors than those from the no-ash control (<i>p</i> <0.001), e.g., >71% reduction through all harvests. Moreover, the 6 wt % treatment produced taller grass leaves and higher biomass yields (<i>p</i> <0.05) relative to other treatments and the control. This potted plant study demonstrated the potential for high-carbon wood ash to reduce PFAS availability to plants while also enhancing plant growth; however, field-based studies are needed to determine if these benefits are sustained under field conditions.