Oral Presentation SETAC Asia-Pacific Virtual Conference 2022

Widespread Occurrence of Liquid Crystal Monomers in Sediments of the Northern South China Sea (#82)

Danyang 1 Tao 1 , Yuhe 2 He 1 , Kenneth 3 Leung 1 , Paul 4 Lam 2
  1. City University of Hong Kong, Kowloon Tong., TAT CHEE AVENUE., Hong Kong
  2. SKLMP, Metropolitan University of Hong Kong, Kowloon Tong., 香港

Liquid crystal monomers (LCMs), commonly used in screens of electronic devices, have recently been identified as a novel group of emerging chemicals of concern, which are potentially persistent, bioaccumulative, and toxic, and may pose a threat to the marine ecosystem. The Northern South China Sea (NSCS) receives organic contamination discharged from the Pearl River Delta region where primitive handling of e-waste is widespread. However, information on the pollution status of LCMs in the NSCS is absent. In this study, a rapid and robust analytical method was established, and the spatial distributions of 39 target LCMs were investigated in 45 surface sediment samples collected in the NSCS in 2018. Ten LCMs were detected, with the total LCMs concentrations ranging from 4.6-187.4 ng/g dry weight. 1-(4-propylcyclohexyl)-4-vinylcyclohexane was the predominant LCM. Our results suggest wastewater effluents discharged from Shenzhen and Hong Kong might be the main sources of LCMs in the NSCS. The total LCMs concentrations in this study were relatively higher compared to many other legacy and emerging organic pollutants found in the same investigated area. Our findings demonstrate the widespread occurrence of LCMs in the NSCS. Further investigations on source appointment will be prerequisite for understanding LCMs local pollution inventory.