Characterization of the Bioavailability of Per- and Polyfluoroalkyl Substances in Farmland Soils and the Factors Impacting Their Translocation to Edible Plant Tissues

In this study, various crops and farmland soils were
collected
from the Fen-Wei Plain, China, to investigate the bioavailability
of perfluoroalkyl substances (PFAS), their accumulation in edible
plant tissues, and the factors impacting their accumulation. PFAS
were frequently detected in all of the crops, with total concentrations
ranging from 0.61 to 35.8 ng/g. The results of sequential extractions
with water, basic methanol, and acidic methanol indicate that water
extraction enables to characterize the bioavailability of PFAS in
soil to edible plant tissues more accurately, especially for the shorter-chain
homologues. The bioavailability of PFAS was remarkably enhanced in
the rhizosphere (RS) soil, with the strongest effect observed for
leafy vegetables. The water-extracted Σ16PFAS in
RS soil was strongly correlated with the content of dissolved organic
carbon in the soil. Tannins and lignin, identified as the main components
of plant root exudates by Fourier transform-ion cyclotron resonance
mass spectrometry, were found to enhance the bioavailability of PFAS
significantly. Redundancy analysis provided strong evidence that the
lipid and protein contents in edible plant tissues play important
roles in the accumulation of short- and long-chain PFAS, respectively.
Additionally, the high water demand of these tissues during the growth
stage greatly facilitated the translocation of PFAS, particularly
for the short-chain homologues and perfluorooctanoic acid.