Comprehensive\nAnalysis beyond Traditional Organophosphate\nEsters (OPEs) Uncovers the Prevalence of Novel OPEs and Related Compounds\nin River Waters

This study aims to comprehensively characterize the occurrence\nand potential risks of organophosphate esters (OPEs), especially the\nnovel OPEs and related compounds present in river waters. Using high-resolution\nmass spectrometry, we conducted a comprehensive analysis of OPE-related\ncompounds in water samples (<i>n</i> = 90) from the Chaobai\nRiver in Beijing, China. Target screening detected 16 traditional\nOPEs with cumulative concentrations of 0.69–1315 ng/L in spring\nand 1.5–1218 ng/L in autumn water samples. Suspect and nontarget\nscreening further identified 42 novel OPEs and related compounds,\nincluding 12 organophosphate triesters, 11 organophosphate diesters,\n7 organophosphonates, 8 organothiophosphate esters, and 4 others.\nThe semiquantified concentrations of these novel compounds make up,\non average, 36% of all OPE-related compounds. Thereinto, 36 novel\ncompounds were discovered in surface water for the first time. Downstream\nsamples exhibited more complex OPE profiles and higher concentrations\ncompared to upstream and reservoir samples, associated with varied\nwatershed characteristics. Hazard assessment and risk-based prioritization\nrevealed significant environmental concerns regarding certain chlorinated\nOPEs and novel compounds, such as bis((5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl)\nmethyl phosphonate <i>P</i>,<i>P</i>’-dioxide,\n2-ethylhexyl hydrogen (2-ethylhexyl)phosphonate, and dihexyl hydrogen\nphosphate. This study underscores the importance of a comprehensive\nanalysis in understanding OPE-related contamination and risks in surface\nwater.