Liquid crystal monomers in human, dog and cat feces from the United States.

Little is known about exposure of humans and companion animals to liquid crystal monomers (LCMs), which are extensively used in digital displays. We determined the concentrations of 52 LCMs in feces of humans, pet dogs and cats from New York State, USA, using gas chromatography-high resolution mass spectrometry (GC-HRMS). Twenty-four, eight, and six LCMs, that were mainly fluorinated, were detected in human, dog, and cat feces, respectively. ∑LCMs concentrations in the feces of humans (mean: 8.01 ng/g dry weight [dw]) were significantly higher (p < 0.05) than those of dogs (mean: 1.82 ng/g dw) and cats (mean: 1.24 ng/g dw) and with concentrations measured as high as 39.8 ng/g dw. Rel-4'-((1r,1'r,4 R,4'R)-4'-ethyl-[1,1'-bi(cyclohexan)]-4-yl)-3,4-difluoro-1,1'-biphenyl (RELEEBCH or 2bcHdFB) was found at the highest detection frequency (DF) among LCMs analyzed in human (DF: 89 %), dog (DF: 28 %), and cat (DF: 50 %) feces, although this compound accounted only < 4 % of ∑LCM concentrations. The mean cumulative daily intakes of ∑LCMs, calculated through a reverse dosimetry approach, were 71.7, 87.5, and 10.7 ng/kg body weight (bw)/day for humans, dogs, and cats, respectively. This study provides evidence of exposure of both humans and pets to LCMs, highlighting the importance of assessing sources of exposure and associated health risks.