Comprehensive Analysis beyond Traditional Organophosphate Esters (OPEs) Uncovers the Prevalence of Novel OPEs and Related Compounds in River Waters

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