Perfluorinated alkyl acids in edible crops:Uptake and distribution inside the plants

This thesis investigates the uptake of perfluorinated alkyl acids (PFAAs) by edible crops. PFAAs are environmental contaminants of concern, also known as “forever chemicals” due to their extremely high persistency. Lettuce, tomato, cabbage and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. In a second experimental setup four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters in soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length. The PFAAs were taken up with the transpiration stream and accumulated primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs. The results presented in this thesis show that uptake of PFAAs by plants is a viable route to get in the human food chain and that root vegetables pose the highest risk for human exposure to long chained PFAAs, while leafy vegetables pose the highest risk for human exposure to short and mid-chain PFAAs

Risk to human health related to the presence of perfluoroalkyl substances in food

Acknowledgements: The Panel wishes to thank the following for their support provided to this scientific output as Hearing experts: Klaus Abraham, Esben Budtz-Jørgensen, Tony Fletcher, Philippe Grandjean, Hans Mielke and Hans Rumke and EFSA staff members: Davide Arcella, Marco Binaglia, Petra Gergelova, Elena Rovesti and Marijke Schutte. The Panel wishes to acknowledge all European competent institutions, Member State bodies and other organisations that provided data for this scientific output. The Panel would also like to thank the following authors and co-authors for providing additional information in relation to their respective studies: Berit Granum, Margie M Peden-Adams, Thomas Webster.Peer reviewedPublisher PD

Perfluorinated alkyl acids in edible crops: Uptake and distribution inside the plants

This thesis investigates the uptake of perfluorinated alkyl acids (PFAAs) by edible crops. PFAAs are environmental contaminants of concern, also known as “forever chemicals” due to their extremely high persistency. Lettuce, tomato, cabbage and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. In a second experimental setup four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters in soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length. The PFAAs were taken up with the transpiration stream and accumulated primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs. The results presented in this thesis show that uptake of PFAAs by plants is a viable route to get in the human food chain and that root vegetables pose the highest risk for human exposure to long chained PFAAs, while leafy vegetables pose the highest risk for human exposure to short and mid-chain PFAAs

Perfluorinated alkyl acids in edible crops: Uptake and distribution inside the plants

This thesis investigates the uptake of perfluorinated alkyl acids (PFAAs) by edible crops. PFAAs are environmental contaminants of concern, also known as “forever chemicals” due to their extremely high persistency. Lettuce, tomato, cabbage and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. In a second experimental setup four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters in soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length. The PFAAs were taken up with the transpiration stream and accumulated primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs. The results presented in this thesis show that uptake of PFAAs by plants is a viable route to get in the human food chain and that root vegetables pose the highest risk for human exposure to long chained PFAAs, while leafy vegetables pose the highest risk for human exposure to short and mid-chain PFAAs

Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa)

An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant