Tracing contaminants of emerging concern and their transformations in the whole treatment process of a municipal wastewater treatment plant using nontarget screening and molecular networking strategies

• Published in: Water research (Oxford) Vol. 267; p. 122522
• Main Authors: Chen, Zhenguo, Xia, Di, Liu, Huangrui, Wang, Rui, Huang, Mingzhi, Tang, Ting, Lu, Guining
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2024
• Subjects: Contaminants of emerging concern; Molecular network; Nontarget screening; Transformation products; Wastewater treatment plant; Transformation products; Wastewater treatment plant; Molecular network; Contaminants of emerging concern; Nontarget screening
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2024.122522

•94.5 % of all compounds detected by NTS strategy was eliminated across WWTP.•510 chemicals were identified in WWTP with 146 pharmaceuticals as largest category.•29 CECs were semiquantified from 2.80 ng/L (Fluconazole) to 10,351 ng/L (Nicotine).•Potential transformation products of CECs across WWTP were tentatively identified. This study employed nontarget screening with high-resolution mass spectrometry and molecular network strategy to characterize the occurrence and tranformation of contaminants of emerging concern (CECs) through a wastewater treatment plant in Guangzhou. We detected 70,631 compounds in positive mode and 14,423 in negative mode in influent, from which 94.5 % of these compounds were successfully eliminated after treatment. Among them, 510 chemicals were identified, with pharmaceuticals being the largest category excluding natural products, accounting for 146 compounds. And 29 CECs were semiquantified with concentrations ranging from 2.80 ng/L (Fluconazole) to 10,351 ng/L (Nicotine). The removal efficiency varied: 60 compounds were easily removable (>90 % removal), 17 were partially removable (40–90 % removal), and 44 were non-degradable (<40 % removal). Additionally, we tentatively identified transformation products (TPs) of CECs using a molecular network analysis, revealing over 20,000 compound pairs sharing common fragments, with 191 compounds potentially linked to 47 level 1 compounds, suggesting their role as TPs of CECs. These findings illuminated the actual treatment efficiency of wastewater treatment plants for CECs and the potential TPs, offering valuable insights for future improvements in wastewater management practices. [Display omitted]