Qualitatively elucidating the molecular characteristics of precursors for saturated halogenated disinfection byproducts in chlorinated urban eutrophic lake water by ultrahigh-resolution mass spectrometry

Lake eutrophication affects the molecular composition of aquatic dissolved organic matter (DOM) and halogenated disinfection byproducts (Xn-DBPs). However, the effects of autochthonous DOM on the Xn-DBPs formation during disinfection of natural eutrophic water from the perspective of biological metabolism are still poorly revealed. Herein, the natural urban eutrophic lake (UEL) water with slight eutrophication was employed to elucidate the discrepancies in Xn-DBPs formation between autochthonous and allochthonous DOM based on the ultrahigh-resolution mass spectrometry. The number and its proportion of nitrogenous Xn-DBPs in chlorinated UEL water samples were significantly larger (p < 0.05) than those for chlorinated SRNOM. Microbes dominated by Microcystis contributed largely to releasing autochthonous DOM for Xn-DBPs formation upon disinfection. The Xn-DBPs species mainly derived from microorganisms were highly saturated, reduced, bioavailable, nitrogenous, and toxic but lowly oxidized and aromatic than terrestrially derived Xn-DBPs species. Moreover, for the first time, the connection between microbial lipid metabolism and Xn-DBPs species exclusively identified in chlorinated UEL water indicated the considerable contribution of lipid metabolites to saturated Xn-DBPs species. The specific biochemical mechanism of Xn-DBPs formation from autochthonous DOM caused by the lysis of microbe cells highlighted the significant contribution of microbial metabolic activities, particularly lipid metabolism, to the generation of highly saturated and nitrogenous Xn-DBPs during chlorination. This study has also reported a novel data interpretation paradigm for Xn-DBPs research, deepening our understanding towards the formation mechanisms of microbe-derived Xn-DBPs species from the view of microbial metabolic pathways.

Subjects

DBP precursor | Disinfection byproducts | Dissolved organic matter | Eutrophication | Fourier transform ion cyclotron resonance mass spectrometry

DDC Class

600: Technology

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Qualitatively elucidating the molecular characteristics of precursors for saturated halogenated disinfection byproducts in chlorinated urban eutrophic lake water by ultrahigh-resolution mass spectrometry