There
is limited information available regarding the bioaccumulation
potential of polyfluoroalkyl substances (PFAS) in urban vegetation.
Using a controlled greenhouse exposure setting, we investigated the
bioaccumulation and translocation of select PFAS in four common urban
spontaneous plants. Target compounds included legacy PFAS (perfluoroalkyl
carboxylic and sulfonic acids, PFCA/PFSA), a fluorotelomer sulfonate
(6:2 FTS), and an emerging fluorinated ether (i.e., hexafluoropropylene
oxide dimer acid (HFPO-DA), or GenX). Results from this study showed
that bioaccumulation factors in root and shoot (BCFroot and BCFshoot) ranged from 0.7 to 83.6 and 0.95 to 26.9,
respectively. Phyllanthus urinaria harbored
the highest PFAS bioaccumulation capacity among the four urban weed
species. The log BCFroot of PFCA homologues showed a concave
shape as a function of chain length, while log BCFroot of
PFSA increased with chain length. The BCFroot of GenX was
lower than that of PFOA; likewise, 6:2 FTS bioaccumulated to a less
extent than PFOS. Root uptake seemed to be the dominant accumulation
mechanism for the shorter-chain compounds, whereas adsorption was
the dominant mechanism for longer-chain compounds such as PFOA. BCFroot and BCFshoot showed consistent trends in response
to foliar and root characteristics. Leaf area and average root diameter
were the most correlated traits with PFAS bioaccumulation factors,
with higher BCF values for plants with smaller leaves and finer roots.
This study also provides an important basis for the role and selection
of urban weeds in future PFAS bioaccumulation and translocation studies
within urban settings.