Multimedia spatial distribution and partitioning behavior of liquid crystal monomers in a typical urbanized river system within the Pearl River Delta, South China.

Liquid crystal monomers (LCMs) have been recognized as contaminants of emerging concerns. However, little is known about their occurrence and partitioning behavior in aquatic system. Water and sediment samples were collected in urbanized river systems within the Pearl River Delta (PRD), South China to investigate the spatial distribution and partitioning behavior of LCMs. The concentrations of Σ44LCM in water ranged from 9.5 to 58 ng/L, with an average of 23 ng/L, whereas those of Σ44LCM in sediments ranged from 9.7 to 120 ng/g dry weight (dw), with an average of 55 ng/g dw. Notably, the sedimentary concentrations of LCMs in the present study are the highest reported to date. Fluorinated biphenyls and their analogs (FBAs) dominated in suspended particulate matter (SPM) and sediments, whereas biphenyls and their analogs (BAs) were more abundant in filtrate. The predominant compound in all matrixes is 1-ethyl-4-[2-(4-methylphenyl) ethynyl] benzene. This study reports for the first time the measured organic carbon-normalized partition coefficients (logKOC) for five LCMs. The partitioning coefficients (logKd) are significantly positively correlated with the organic carbon content (P < 0.05), indicating that organic carbon is the primary factor influencing the partitioning behavior of LCMs. These findings provide a deeper understanding of the distribution and partitioning behavior of LCMs in aquatic environments, facilitating the understanding of their environmental behavior and ecological risks in aquatic environments.