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

Abstract

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.