Partitioning, renal clearance, and internal exposure assessment of liquid crystal monomers (LCMs): Based on paired serum and urine of general population in Northwest China

Liquid crystal monomers (LCMs), which are the key material of liquid crystal displays, have been recently considered as potential persistent, bioaccumulative, and toxic (PBT) chemicals. However, there is limited information on the accumulation and metabolism of LCMs in humans. In this study, a total of 162 paired serum and urine samples of a general population (aged 19 - 70 years) residing in Northwest China were collected and analyzed for the concentrations of 15 representative LCMs. The mean ∑15LCMs concentrations were 129.13 and 38.52   ng/mL in the serum and urine, respectively. BEEB was found to be the most P&B LCM and dominated both serum and urine. DFPrB accumulated remarkably in the serum, while PBIPHCN and BEEB were more easily eliminated by the kidneys. The strong correlations of some LCMs in the paired serum and urine suggest that urinary LCM concentrations can reflect their metabolic levels in the body. The estimated daily intake of ∑15LCMs for the study participants based on the serum data was 3.41   ng/kg body weight/day, and the hazard index of ∑15LCMs was 5.23×10 -5 which is acceptable (< 1). This study provides the evidence for the presence of LCMs in the serum and urine of general population and highlights the renal clearance of LCMs in the human body.