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As novel alternatives to legacy perfluoroalkyl substances, perfluorophosphinates (PFPiAs) and perflurorophosphonates (PFPAs) are widely applied in industrial and agricultural fields and are supposed to be largely partitioned to soil and highly persistent. It is of particular interest to understand their transfer from roots to shoots and their transformation in plants, such as wheat. The results of hydroponic experiments indicated that C6/C6 PFPiAs, C8/C8 PFPiA, perfluorooctanophosphonic acid (PFOPA) and perfluorohexaphosphonic acid (PFHxPA) were quickly adsorbed on the epidermis of wheat root (Triticum aestivum L.), which was driven by their hydrophobicity. A small fraction of the accumulated PFPiAs and PFPAs in the wheat root was subjected to absorption via an active process dependent on H+-ATPase. PFHxPA, which has the smallest molecular weight and medium hydrophilicity (1<log Kow<4), displayed the strongest absorption efficiency via the water and anion channels and had highest translocation potential. C6/C6 and C8/C8 PFPiAs experienced phase I metabolism in wheat to form more persistent PFHxPA and PFOPA, respectively, as well as 1H-perfluorohexane (1H-PFHx) and 1H-perfluorooctane (1H-PFO), which were regulated by cytochrome P450 in wheat root. As a result, exposure to PFPiAs in roots ultimately caused the accumulation of more persistent PFPAs in the above ground parts of plants, raising concerns about their potential risks to human health.
PMID: 31795634 [PubMed - as supplied by publisher]