Characterization of Dissolved Organic Matter and Its Derived Disinfection Byproduct Formation along the Yangtze River

Abstract

The Yangtze River basin covers one-fifth of China’s land area and serves as a water source for one-third of China’s population. During long-distance water transport from upstream to downstream, various sources of dissolved organic matter (DOM) lead to considerable variation in DOM properties, significantly impacting water treatability and disinfection byproduct (DBP) formation after chlorination. Using size-exclusion chromatography and fluorescence spectroscopy, the spatial variation in DOM characteristics was comprehensively investigated on a basin scale. The formation of 36 DBPs and speciated total organic halogen in chlorinated samples was determined. Overall, the Yangtze River waters featured a high proportion of terrestrially derived humic substances that served as important precursors for trihalomethanes and haloacetic acids, which was responsible for the increase in total DBP formation along the Yangtze River. The downstream waters were characterized by high levels of microbially derived protein-like biopolymers, which significantly contributed to the formation of haloacetaldehydes and haloacetonitriles that dominated DBP-associated mammalian cell cytotoxicity. Moreover, the precursors of haloacetaldehydes and haloacetonitriles in downstream waters were highly hydrophilic, posing a challenge for water treatment. This study presents an extensive basin-scale study, providing insights into DOM variations along the Yangtze River, illustrating the impact of DOM properties on drinking water from a DBP perspective.

Drivers of variability in disinfection by-product formation potential in a chain of thermally stratified drinking water reservoirs

“…S2, Tables S1, S3, S5 and S7), suggesting that S9-S12), suggest that DOM across the four systems was a mixture of both humiclike and microbial derived, the maxima of HIX, BIX and FI indicate that a larger proportion of DOM was humic in nature, 23,38,39 that preferentially forms carbonaceous DBPs. 40 3.2 Effect of the system on disinfection by-product FP Contrary to the initial hypotheses, the median values of TTHM FP increased across the river-reservoirs chain (Fig. 1), ranging from 33 μg L −1 to 90 μg L −1 .…”

Carbonaceous DBP (THMs and HAAs) formation during Cl2 and ClO2 treatment of aqueous soluble fractions of soil derived natural organic matter

“…28,29 The formation of THMs and HAAs from the transphilic components was reported to be lower than those of the corresponding hydrophobic and hydrophilic fractions. 21 On the other hand, the order of THM formation observed by Musikavong et al (2016) 30 from the different organic fractions was hydrophobic > transphilic > hydrophilic. Chlorine is the most commonly used disinfectant for water treatment.…”

“…18–20 Fractionation of the DOM into these homogeneous components helps to reveal the interrelationship between DBP formation and the DOM characteristics. 21 DOM found in natural water generally comprises hydrophobic acids and is reported to be made up of approximately 50% dissolved organic content (DOC), comprising humic and fulvic acids. 22,23 The humic substances are generally regarded as the main precursors of DBP formation.…”

Identification of disinfection by-product precursors by natural organic matter fractionation: a review

“…have equally important trihalomethane formation potential as hydrophobic organics at short reaction times (~ 40%), while transphilic organic matter seems slightly more reactive after 7 days of reaction and high chlorine dose (Fig. 7b,d) (Agbaba et al, 2014;Chowdhury et al, 2008;Fang et al, 2021;Goslan et al, 2002;Goslan et al, 2004;Hanigan et al, 2013;Hu et al, 2015;Hua and Reckhow, 2007b;Hua et al, 2015;Li et al, 2014;Lin and Wang, 2011;Lin et al, 2014;Liu et al, 2011;Molnar et al, 2012a;Molnar et al, 2013;Molnar et al, 2012b;Musikavong et al, 2016;Niu et al, 2015;Phetrak et al, 2016;Pi et al, 2021;Roccaro et al, 2014;Smith and Al Qabany, 2009;Tubić et al, 2013;Wang et al, 2013;Wei et al, 2008a;Wei et al, 2008b;Xu et al, 2007;Xue et al, 2010;Zhang et al, 2021;Zhao et al, 2013;Zhi-sheng et al, 2009).…”