Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Amsterdam, The Netherlands.
Environ Sci Technol. 2012 Nov 6;46(21):11735-43. doi: 10.1021/es302398u. Epub 2012 Oct 18.
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.
开展了一项摄取研究，以评估通过食用蔬菜摄入全氟烷基酸 (PFAAs) 对人体的潜在暴露风险。生菜 (Lactuca sativa) 在四种不同浓度（从 10ng/L 到 10μg/L）的含 PFAAs 营养溶液中生长。采用 HPLC-MS/MS 分析了 11 种全氟羧酸 (PFCAs) 和 3 种全氟磺酸 (PFSAs)。实验结束时，植物吸收的每种 PFAAs（除了短链，C4-C7，PFCAs）的大部分总质量似乎都保留在不可食用的部分，即根部。计算了根浓度系数 (RCF)、茎叶/根浓度系数 (FRCF) 和蒸腾流浓度系数 (TSCF)。对于长链 PFAAs，RCF 值最高，而 FRCF 值最低。这表明根吸收可能受 PFAAs 与富含脂质的根固体的吸附控制。从根部向茎叶的转移受到限制，并且高度依赖于化合物的疏水性。尽管 TSCF 表明较长链的 PFCAs（例如全氟十二烷酸）比较短链的 PFCAs（例如全氟庚酸）更好地从营养液转移到茎叶，但由于来自添加溶液的额外吸附，长链 PFCAs 的主要部分仍存在于根部。由于氟原子的强吸电子效应，离解 PFAAs 的负电荷的作用可能并不重要。
