Abstract:
Liquid crystal monomers (LCMs) are a class of emerging contaminants of concern predicted to be persistent, bioaccumulative and toxic (PBT). Being one of the key components in liquid crystal displays (LCDs), the disposal of LCD containing devices is closely related to the emission of LCMs into the environment. LCMs have been detected in a wide range of environmental matrices including dust, sediment, soil, sewage leachate, and air, with concentration ranges between 17 and 2121 ng/g found in indoor residential dust. Furthermore, they have been detected on human skin at concentrations up to 2,071,000 ng/m2 and in the serum of e-waste dismantling workers, at concentrations ranging from 3.9 to 276 ng/mL. Despite the far-reaching contamination of these compounds, there is limited knowledge of their environmental behaviour, fate, and toxicity. Model predictions show that 297 of 330 LCMs are persistent and bioaccumulative compounds, with many more indicated as being toxic. However, current knowledge of their physicochemical and PBT properties is largely restricted to theoretical predictions and limited to a small number of experimental toxicity studies. As an emerging class of contaminants of concern, a lack of standardisation between studies was identified as a key challenge to advancing the state of knowledge of these compounds. Not only are harmonised analytical methods for their determination and quantification in environmental media yet to be established, but there is also a need for a universal abbreviation system. To further harmonise the reporting of data on LCMs we propose reporting the sum concentration of ten priority LCMs, selected on the basis detection frequency, toxicity and potential for human exposure. Of the ten priority LCMs five are fluorinated biphenyls and analogues, four are biphenyls/bicyclohexyls and analogues and one is a cyanobiphenyl.
摘要:
液晶单体(LCM)是一类新兴的污染物,预计具有持久性,生物蓄积性和毒性(PBT)。作为液晶显示器(LCD)的关键部件之一,含有LCD的器件的处理与LCM向环境中的排放密切相关。LCM已经在包括灰尘在内的各种环境基质中被检测到,沉积物,土壤,污水渗滤液,和空气,室内住宅粉尘中的浓度范围在17至2121纳克/克之间。此外,在人体皮肤和电子废物拆解工人血清中检测到的浓度高达2,071,000纳克/平方米,浓度范围为3.9至276ng/mL。尽管这些化合物受到了深远的污染,他们对环境行为的了解有限,命运,和毒性。模型预测表明,330个LCM中有297个是持久性和生物蓄积性化合物,还有更多的被认为是有毒的。然而,目前对其物理化学和PBT性质的了解在很大程度上仅限于理论预测,并且仅限于少量的实验毒性研究。作为一种新兴的污染物,研究之间缺乏标准化被认为是提高这些化合物知识水平的关键挑战.不仅在环境介质中确定和量化的统一分析方法尚未建立,但也需要一个通用的缩写系统。为了进一步协调LCM的数据报告,我们建议报告十个优先LCM的总集中,根据检测频率选择,毒性和人体暴露的潜力。在十个优先LCM中,有五个是氟化联苯和类似物,四个是联苯/双环己基和类似物,一个是氰基联苯。