Fluorescent Dissolved Organic Matter Components as Surrogates for Disinfection Byproduct Formation in Drinking Water: A Critical Review

Disinfection byproduct(DBP) formation, prediction, and minimizationare critical challenges facing the drinking water treatment industryworldwide where chemical disinfection is required to inactivate pathogenicmicroorganisms. Fluorescence excitation-emission matrices-parallelfactor analysis (EEM-PARAFAC) is used to characterize and quantifyfluorescent dissolved organic matter (FDOM) components in aquaticsystems and may offer considerable promise as a low-cost optical surrogatefor DBP formation in treated drinking waters. However, the globalutility of this approach for quantification and prediction of specificDBP classes or species has not been widely explored to date. Hence,this critical review aims to elucidate recurring empirical relationshipsbetween common environmental fluorophores (identified by PARAFAC)and DBP concentrations produced during water disinfection. From 45selected peer-reviewed articles, 218 statistically significant linearrelationships (R (2) >= 0.5) with oneor more DBP classes or species were established. Trihalomethanes (THMs)and haloacetic acids (HAAs), as key regulated classes, were extensivelyinvestigated and exhibited strong, recurrent relationships with ubiquitoushumic/fulvic-like FDOM components, highlighting their potential assurrogates for carbonaceous DBP formation. Conversely, observed relationshipsbetween nitrogenous DBP classes, such as haloacetonitriles (HANs),halonitromethanes (HNMs), and N-nitrosamines (NAs),and PARAFAC fluorophores were more ambiguous, but preferential relationshipswith protein-like components in the case of algal/microbial FDOM sourceswere noted. This review highlights the challenges of transposing site-specificor FDOM source-specific empirical relationships between PARAFAC componentand DBP formation potential to a global model.