Second derivative UV–visible spectroscopy characterizing structural components of dissolved and particulate organic matter in an urbanized river

Abstract Background Spatio-temporal variations of structural components the POM–DOM fractions exhibit in urban rivers, which is valuable information to reveal dynamic migration and transformation within between organic matter pools, also provide important support for river water quality improvement management measures. Second derivative UV–visible spectroscopy (SDUVS) was applied simultaneously characterize spatial dissolved (DOM: Diameter < 0.2 μm) particulate (POM1: diameter 0.7 μm; POM2: > matters an urbanized northeast China. Results Thirty-six samples were collected from mainstream tributaries along a human impact gradient, i.e., rural, town regions. The DOM representative fraction natural pool, mostly derived allochthonous terrestrial sources. Four C1 C4 identified by SDUVS. associated with phenolic groups C2 related carboxylic dominant pool. C3 composed primary humificated materials, %C3 kept relatively consistent presented deeply increase aromatic alkyl structures. average %C4 POM pool higher than that indicating humification degree fraction. Conclusions Moreover, had mainstream, trends similar trophic level decreased order region rural region, while molecular sizes region. Graphical