PFAS Uptake in Wheatgrass Microgreens

PFAS (per- and polyfluoroalkyl substances) are a group of chemicals that are broadly used today for waterproofing, stain-resistant carpets and rugs, non-stick surfaces, and fire extinguishing foam, among other uses. These chemicals are environmentally and biologically persistent and became globally pervasive before we knew of their harm. Perfluorooctanesulfonic acid (PFOS) is known as a "legacy" PFAS, as it is one of the first of such chemicals to be synthesized and widely used. As PFOS has been released into the environment globally, it is important to understand its environmental fate and transport. Hexafluoropropylene oxide dimer acid (HFPO-DA) is a "GenX" PFASchemical, part of a group of chemicals which have become replacements for legacy PFAS as their negative effects have become more widely known. Knowing that PFOS and HFPO-DA can contaminate surface and groundwater, I sought to explore the ability of plants, specifically wheatgrass, grown using contaminated water to take up these PFAS. Wheatgrass microgreens were chosen as they are more water-intensive than other plants, suggesting they may show more signs of contamination. The edible portion (stems and leaves) of wheatgrass grown in PFAS-contaminated water was harvested and extracted with methanol; the extract was analyzed by liquid chromatography-mass spectrometry to quantify the PFAS uptake. Initial findings suggest that PFOS and HFPO-DA are taken up by wheatgrass into the leaf and stem. It is known that PFOS is much more attracted to soil than to water, so it is expected to concentrate within the roots if it is taken up by the plant. HFPO-DA was used as a comparison as the chemical structure suggests that it may travel into the edible portion of the plant with greater ease than PFOS. Ongoing research is focused on quantifying the amounts of PFOS and HFPO-DA in the roots, stems, and leaves of wheatgrass grown in water with varying PFAS concentrations.