Characterizing the
occurrence, sources, and fate of organic micropollutants
(OMPs) in lake–river systems serves as an important foundation
for constraining the potential impacts of OMPs on the ecosystem functions
of these critical landscape features. In this work, we combined suspect
and nontarget screening with mass balance modeling to investigate
OMP contamination in the Onondaga Lake–Three Rivers system
of New York. Suspect and nontarget screening enabled by liquid chromatography–high-resolution
mass spectrometry led to the confirmation and quantification of 105
OMPs in water samples collected throughout the lake–river system,
which were grouped by their concentration patterns into wastewater-derived
and mixed-source clusters via hierarchical cluster analysis. Four
of these OMPs (i.e., galaxolidone, diphenylphosphinic acid, N-butylbenzenesulfonamide, and triisopropanolamine) were
prioritized and identified by nontarget screening based on their characteristic
vertical distribution patterns during thermal stratification in Onondaga
Lake. Mass balance modeling performed using the concentration and
discharge data highlighted the export of OMPs from Onondaga Lake to
the Three Rivers as a major contributor to the OMP budget in this
lake–river system. Overall, this work demonstrated the utility
of an integrated screening and modeling framework that can be adapted
for OMP characterization, fate assessment, and load apportionment
in similar surface water systems.