Identification of Environmental Liquid-Crystal Monomers: A Class of New Persistent Organic Pollutants—Fluorinated Biphenyls and Analogues—Emitted from E-Waste Dismantling

Abstract

Liquid-crystal monomers (LCMs), especially fluorinated biphenyls and analogues (FBAs), are considered to be a new generation of persistent, bioaccumulative, and toxic organic pollutants, but their emissions from liquid-crystal display (LCD)-associated e-waste dismantling remain unknown. To fill this knowledge gap, a broad range of 46 LCMs, including 39 FBAs and 7 biphenyls/bicyclohexyls and analogues (BAs), were investigated by a dedicated target analysis in e-waste dust samples. Of 39 target FBAs, 34 were detected in LCD dismantlingassociated dust. Among these 34 detectable FBAs, 9 were detected in 100% of the samples and 25 were frequently detected in >50% of the samples. The total concentrations of these 34 FBAs (∑ 34 FBAs) detected in LCD e-waste dust were in the range of 225−976,000 (median: 18,500) ng/g, significantly higher than those in non-LCD e-waste dust (range: 292−18,500, median: 2300 ng/g). In addition to FBAs, six of seven BAs were also frequently detected in LCD e-waste dust with total concentrations (∑ 6 BAs) of 29.8−269,000 (median: 3470) ng/g. Very strong and significant correlations (P < 0.01) were identified in all frequently detected LCMs, indicating their common applications and similar sources. Our findings demonstrate that e-waste dismantling contributes elevated emissions of FBAs and BAs to the ambient environment.

Comprehensive Identification of Liquid Crystal Monomers—Biphenyls, Cyanobiphenyls, Fluorinated Biphenyls, and their Analogues—in Waste LCD Panels and the First Estimate of their Global Release into the Environment

“…Among these 10 less frequently detected BAs, except MPB with high content in some brand television LCDs, the others showed relatively low contents, indicating their less use as minor BA-type LCMs in LCDs. Consistent with the present findings on BAs prioritized in waste LCDs here, EBMB, PVB, MPCB were previously reported to be frequently detected in LCD-dismantling associated e-waste dust . However, EPB and MPB were found with low DFs in waste LCDs but frequently detected in e-waste dust, indicating their easy escape from the waste LCD sources.…”

“…The present study builds on and continues from our previous investigation on the e-waste driven massive emission of LCMs and extends the investigation to the source and inventory of LCMs at the same e-waste recycling area. The availability of a much larger number of LCM standards than before makes it possible to construct the LCM emission inventory.…”

“…Currently, the most common disposal measures for finally discarded LCD wastes are pyrolysis, incineration, and landfill disposal. ,,,, LCMs will be inevitably and continually released and transported from sources to the air, soil, and water during these disposal processes. Given the P&B&T properties of LCMs, as we emphasized in our previous study, more field studies are urgently needed to reveal their environmental occurrence, behavior, fate, and toxicities. Meanwhile, routine monitoring and regulation measures should be considered by government departments in the future.…”

“…The researchers from China further found LCMs present in sediments from three typical areas. 23 Our recent study 24 reported the e-waste dismantling drove massive emission of large quantities of LCMs from waste LCD panels at e-waste recycling areas, with even comparable concentrations to those of polybrominated diphenyl ethers. This awakens us that further studies are urgently needed to elucidate the source emission, behavior, and fate of LCMs in the environments, especially in the e-waste recycling area.…”

Organofluorine Mass Balance Analysis of Whole Blood Samples in Relation to Gender and Age

“…60 Indoor dust has been reported to contain fluorinated liquid crystal monomers (LCMs), and these compounds could represent an additional source of UOF through dust inhalation since 48% of the currently produced LCMs contain fluorine. 61 Fluorinated LCMs have been reported in dust from e-waste dust 62 and in sediment samples from China, 63 indicating environmental presence and potential for additional human exposure.…”