Occurrence of dissolved organic matter in storm-drain inlet sediments and its implication for urban stormwater infrastructure sustainability

In the context of climate change, the effective management of carbon in urban stormwater infrastructure (USI) become increasingly crucial. Research indicates that dissolved organic matter (DOM) plays a significant role in the carbon cycle within USI. However, there is a lack of comprehensive information regarding the occurrence of DOM in urban storm-drain inlet (SDI) sediments. This study was undertaken to examine the land use type-related distribution of DOM in SDI sediments, and then provide the suggestion for urban infrastructure sustainability. There are three findings: (1) The characteristics of DOM in SDI sediments, including content, hydrophilicity, molecular weight, and functional groups of aromatic rings, exhibited variation with land functional type; (2) Urban SDI DOM had low humification, and was primarily originated from autochthonous sources, with the proportion of humic-like components close to or exceeding 50%; and (3) SDI sediment DOM was likely to have different characteristics from road dust and stormwater due to microbial activities over dry season. Based on these findings, measures for urban stormwater infrastructure sustainability are proposed, including properly road sweeping, frequently SDI sediment dredging, decreasing in emission from industrial activities, promoting local educational practices, and limiting improper organic waste disposal. These results have implications for the management of stormwater-related carbon and provide valuable insights for the development of sustainable practices for urban ecosystems.