Foliar uptake overweighs root uptake for 8:2 fluorotelomer alcohol in ryegrass (Lolium perenne L.): A closed exposure chamber study

Abstract

Fluorotelomer alcohols (FTOHs) are a kind of volatile monomers that can be released from FTOH-based products and their ubiquitous occurrence raises concerns for their plant uptake. To study plant uptake pathway, translocation, and transformation characteristics of 8:2 FTOH, ryegrass (Lolium perenne L.) was selected as a model plant for 8:2 FTOH exposure via air and/or soil uptake for 4 weeks in custom-built closed exposure chambers. The bio-degradation of spiked 8:2 FTOH in the soil led to the production of C6-C8 perfluoroalkyl carboxylic acids (PFCAs) and other intermediates, and perfluorooctanoic acid (PFOA) was the main product (54.9%-88.9%). In the ryegrass, foliar uptake of 8:2 FTOH contributed 78.1% ± 3.4% to the total shoot accumulation while PFOA in shoot was mainly from root uptake of PFOA and the further biotransformation of other unmonitored intermediates biodegraded from 8:2 FTOH in the soil (83.7% ± 7.3%). The results in this study provides the first laboratory evidences that foliar uptake of airborne 8:2 FTOH can be a major pathway over root uptake and its subsequent biotransformation contribute to the burden of PFCA accumulation in plants.

Keywords: 8:2 FTOH; Foliar uptake; Root uptake; Ryegrass; Transformation; Translocation.