Liquid crystal monomers (LCMs) are used widely in liquid crystal displays (LCDs), which are dramatically changing the world due to the provision of convenient communication. However, there are essentially no published reports on the fate and/or effects of LCMs in the environment. Of 362 currently produced LCMs, 87 were identified as persistent and bioaccumulative (P&B) chemicals, which indicated that these chemicals would exhibit resistance to degradation and exhibit mobility after entering the environment. Following exposure to mixtures of LCM collected from 6 LCD devices, significant modulation of 5 genes,CYP1A4,PDK4,FGF19,LBFABP, andTHRSP, was observed in vitro. Modulation of expressions of mRNAs coding for these genes has frequently been reported for toxic (T) persistent organic pollutants (POPs). In LCM mixtures, 33 individual LCMs were identified by use of mass spectrometry and screened for in 53 samples of dust from indoor environments. LCMs were detectable in 47% of analyzed samples, and 17 of the 33 LCMs were detectable in at least 1 sample of dust. Based on chemical properties, including P&B&T of LCMs and their ubiquitous detection in dust samples, the initial screening information suggests a need for studies to determine status and trends in concentrations of LCMs in various environmental matrices as well as tissues of humans and wildlife. There is also a need for more comprehensive in vivo studies to determine toxic effects and potencies of LCMs during chronic, sublethal exposures.
Liquid
crystal monomers (LCMs) have been proposed to be persistent,
bioaccumulative, and toxic (PBT) substances; however, there is a dearth
of information regarding their occurrence in sediment samples. Here,
an analytical method was developed for the quantitative determination
of LCMs in sediment samples, and n = 76 sediment
samples were collected and analyzed to determine accurate concentrations
of LCMs. Our results indicated that the developed pretreatment procedure
was applicable for the determination of LCM concentrations in sediments.
We observed that LCMs were detected in 75 out of the 76 sediment samples,
and 23, 18, and 14 out of the 39 target LCMs were quantified in at
least one of the analyzed sediments from rivers around LCM or liquid
crystal device (LCD) manufacturers, Taihu Lake, and rivers around
e-waste recycling sites, respectively. The LCMs in the samples from
rivers around LCM/LCD manufacturers exhibited the greatest mean concentrations
of 26.1 ng/g dry weight (dw), followed by those from e-waste recycling
site areas (1.15 ng/g dw) and Taihu Lake (0.076 ng/g dw). Collectively,
this study provided the first analytical method that was able to quantify
the concentrations of LCMs in sediment samples and provided the first
evidence for the occurrence of LCMs in sediment samples.
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