Occurrences of perfluoroalkyl and polyfluoroalkyl substances in tree bark: Interspecies variability related to chain length
By Yanwei Liu, Xingwang Hou, Weifang Chen, Wenqian Kong, Dingyi Wang, Jiyan Liu, and Guibin Jiang
Sci. of The Tot. Env.
October 14, 2019
DOI: 10.1016/j.scitotenv.2019.06.454
Abstract
Occurrences of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in tree bark from four species were investigated. Species-dependent congener distribution patterns were firstly reported for perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs). The majority of PFSAs and PFCAs in Chinese red pine bark were C5–C7 PFSAs and perfluorohexanoic acid (PFHxA, containing six carbon atoms, C6), whereas perfluorobutanesulfonic acid (PFBS, C4) and longer chain congeners (PFCAs: C ≥ 7; PFSAs: C ≥ 8) took a larger proportion in the fissured bark from Canadian poplar, Chinese scholartree and weeping willow. The species-dependent congener profiles depended on the structures and chemical compositions of tree bark, as well as the translocation of PFASs within plants. Different tree bark characteristics caused different retention abilities for particle-bound and gaseous PFASs. Particle-bound PFASs retained in the rougher structures of fissured bark led to preferential retention of long chain congeners (the major fraction in the particle phase), while lipid-rich Chinese red pine bark retained more gaseous PFASs (mainly short chain congeners). Besides, the abundance of short chain PFASs in red pine bark was consistent with the chain length-dependent translocation behaviors of PFASs in various plants, suggesting that translocation of PFASs within plants to tree bark may be invovled.
Highlights
• Species-dependent bark accumulation of PFASs was firstly observed and explored.
• Gaseous diffusion and plant translocation contributed to more short chain PFASs occurring in Chinese red pine bark.
• Particle entrapment was responsible for preferential accumulation of long chain PFASs in fissure bark.
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