Bioaccumulation and Translocation of 6:2 Fluorotelomer Sulfonate, GenX, and Perfluoroalkyl Acids by Urban Spontaneous Plants

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 (BCF(root )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 BCF(root )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. BCF(root )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.

Automated summary

Limited information is available on the bioaccumulation potential of polyfluoroalkyl substances (PFAS) in urban vegetation. This study investigated the bioaccumulation and translocation of select PFAS in four common urban spontaneous plants using a controlled greenhouse exposure setting. The results show that different PFAS compounds have varying bioaccumulation factors in roots and shoots, and Phyllanthus urinaria has the highest bioaccumulation capacity among the four weed species. Leaf area and average root diameter were found to be the most correlated traits with PFAS bioaccumulation factors.