Accumulation and effects of perfluoroalkyl substances in three hydroponically grown Salix L. species

The potential of young rooted cuttings of three Salix L. species plants to accumulate a mixture of eleven perfluoroalkyl substances (PFASs), in particular, perfluoroalkyl acids (PFAAs), from the nutrient solution and their effects on plant growth and photosynthesis were assessed in an 8-day experiment. The growth rate of the willow plants exposed to the PFAA mixture was not much affected except for S. triandra. Regarding photosynthesis, the gas exchange parameters were affected more than those related to chlorophyll fluorescence, with significant increase of the net CO₂ assimilation rate and parameters related to stomatal conductance. A decreasing trend in the PFAA concentration in leaves with increasing carbon chain length was observed, whereas long-chain PFAAs showed higher concentrations in roots. Accordingly, the foliage to root concentration factor highlighted that PFAAs with shorter carbon chain length (C ≤ 7) translocated and accumulated relatively more in leaves compared to roots. Removal efficiency of individual PFAAs for leaves and roots were comparatively higher with S. eleagnos and S. purpurea than S. triandra, with mean removal values at the whole plant level ranging around 10% of the amount initially spiked, suggesting their potential for phytoremediation of PFASs.