Dietary Exposure and Health Risk of the Emerging Contaminant Fluorinated Liquid-Crystal Monomers

Fluorinated liquid-crystal monomers (FLCMs) widely used in liquid crystal displays are considered to be a new generation of persistent, bioaccumulative, and toxic contaminants. They have been widely detected in the environment. However, little is known about their occurrence in food and human dietary exposure until now. Herein, we provided an evaluation of dietary exposure and health risks of FLCMs in the Chinese adult population based on the fifth and sixth total diet studies (TDSs). The detection frequencies of FLCMs in the two surveys were 90.5 and 99.5%, with concentrations ranging from not detected ∼72.6 μg/kg wet weight (ww) and ND ∼74.7 μg/kg ww, respectively. All TDS samples contained the multiresidue of FLCMs. The mean estimated daily intakes (EDIs) of FLCMs were 172.86 and 163.10 ng/kg bw/day in the fifth and sixth TDS, respectively. Meats, vegetables, and cereals contributed the most to the EDI of FLCMs. According to the threshold of toxicological concern (TTC) method, the EDIs of 1-fluoro-4-[2-(4-propylphenyl)ethynyl]benzene (4.56 and 3.26 ng/kg bw/day) and 2-fluoro-4-[4'-propyl-1,1'-bi(cyclohexyl)-4-yl]phenyl trifluoromethyl ether (3.12 and 3.28 ng/kg bw/day) were above their TTC value (2.5 ng/kg bw/day), suggesting their potential health risk. This is the first comprehensive national dietary exposure assessment of FLCMs.