Fluorinated liquid-crystal monomers in paired breast milk and indoor dust: A pilot prospective study

Fluorinated liquid-crystal monomers (FLCMs), one class of emerging persistent, bioaccumulative and toxic (PBT) compounds, are widely used in liquid-crystal displays (LCDs). As a result, they have been found in the envi-ronment and serum from occupational workers. However, little is known about their occurrence in non -occupational exposing populations. Herein, we provided an evaluation of the health risks of FLCMs for infants based on breastfeeding exposure and dust ingestion. The detection frequencies (DF) of FLCMs in indoor dust and breast milk was 100 %, with median concentrations of 12.00 ng/g dry weight (dw) and 133.40 ng/g lipid weight (lw), respectively. 1-butoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene (BDPrB) was the predominant pollutant in indoor dust and human breast milk. Significant positive correlations were observed between the dust concentrations of seven FLCMs including BDPrB, and their breast milk concentrations (r = 0.275-0.660, P < 0.05). Further, associations were also found in some demographic and behavioral factors and concentrations of some FLCMs (P < 0.05). The highest EDI of n-ary sumation FLCMs was observed for infants who were < 1 month of age, with a median breast milk intake of 700.35 ng/kg bw/day, in which 1-ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl) benzene (EDPrB), BDPrB, and 4 '-[(trans, trans)-4 '-butyl[1,1 '-bicyclohexyl]-4-yl]-3,4-difluoro-1,1 '-biphenyl (BBDB) collectively contributed 94.4 % of the total EDIs. Notably, the lactational intake of FLCMs was higher than that of some environmental pollutants (EPs). Overall, our results suggest higher exposure risks for infants and breastfeeding is the predominant exposure route for daily intake of FLCMs for infants.

Automated summary

This study evaluated the health risks of fluorinated liquid-crystal monomers (FLCMs) for infants through breastfeeding and dust ingestion. FLCMs were detected in indoor dust and breast milk at a detection frequency of 100%, with concentrations of 12.00 ng/g dry weight and 133.40 ng/g lipid weight, respectively. BDPrB was the most common pollutant in indoor dust and human breast milk. Significant correlations were found between dust and milk concentrations of FLCMs.