Uptake of cyclic C6O4 in maize and tomato: Results from a greenhouse study

Cyclic C6O4 (cC6O4, CAS number 1190931-27-1) is a perfluoralkyl ether used as a polymerization aid in the synthesis of fluoropolymers and produced since 2011 as substitute of PFOA. This work reports the first data on bioaccumulation of cC6O4 on terrestrial plants (maize and tomato). In general, the observed accumulation and translocation of cC6O4 in plants is low or negligible. For maize a bioconcentration factor (BCFdw/dw) of about 39 was observed in the root compartment and much lower (BCFdw/dw = 12) in the aboveground tissues. In tomato the observed BCFs are substantially lower, with a maximum of 2.5 in leaves. The differences observed between the uptake and distribution of cC6O4 in maize and tomato plants are probably due to differences in plant physiology (but also in the experimental design of the tests). Maize plants grown at different concentrations in this study did not show relevant differences in term of biomass and growth, while tomato plants exposed to cC6O4 were subject to a delay in the ripening of the fruits (and relative biomass). The overall results are discussed in comparison with literature data available for legacy PFASs but the comparison is difficult due to differences in the experimental design. It is relevant to note that the concentrations tested in this study are significantly higher than expected environmental concentrations.