Urban river pollution causes serious problems to the environment, human health, and water scarcity. Developing tools to identify and assess the health of aquatic river systems is essential for monitoring the quality of rivers and implementing actions. This study assesses the elemental and molecular characteristics of organic matter (OM) extracted from river sediments and associates them with river quality. To assess the quality of sediment cores, the most reactive and available OM from two urban rivers (Tietê and Piracicaba Rivers, São Paulo, Brazil) was isolated with alkaline and water solutions. It was then characterized by elemental composition, ultraviolet–visible spectroscopy, and fluorescence excitation-emission matrix with parallel factor analysis. The average yield of alkaline extraction was 40.71% ± 5.52% of OM present in the bulk sediments. Extracted organic matter from sediments (EOMSed) from the Tietê River presented the highest average concentrations of non-purgeable organic carbon (NPOC) and total organic nitrogen (TON), and the lowest average NPOC/TON molar ratios and specific UV absorbance at 254 nm (SUVA₂₅₄). Considering the high degree of eutrophication in the Tietê River, these results suggest a greater input of simple OM with nitrogenous structures. The humic-like component in EOMSed was the most abundant in both rivers. The aromaticity of EOMSed from the Piracicaba River was evidenced by the greater contribution of complex structures in the form of aromatic and polyaromatic moieties and higher SUVA₂₅₄. EOMSed from the Tietê River also featured enhanced biological activity due to the greater contribution of microbial-derived products and the presence of small molecules and nitrogenous structures. As this combination of elemental and spectroscopic techniques successfully identified the characteristics of extracted OM, it can be used as a tool to assess the global river quality.

城市河流污染给环境、人类健康和水资源短缺带来了严重的问题。开发用于识别和评估水生河流系统健康状况的工具对于监测河流质量和实施行动至关重要。本研究评估了从河流沉积物中提取的有机质 (OM) 的元素和分子特征，并将其与河流质量联系起来。为了评估沉积物核心的质量，用碱性溶液和水溶液分离了来自两条城市河流（Tietê 和 Piracicaba 河，巴西圣保罗）中反应性最强和可用的 OM。然后通过元素组成、紫外-可见光谱和具有平行因子分析的荧光激发-发射矩阵对其进行表征。碱提的平均收率为40.71%±5。52% 的 OM 存在于大量沉积物中。从铁特河沉积物中提取的有机物 (EOMSed) 呈现出最高平均浓度的不可净化有机碳 (NPOC) 和总有机氮 (TON)，以及最低的平均 NPOC/TON 摩尔比和 254 nm 处的特定紫外吸收(SUVA₂₅₄ )。考虑到铁特河的高度富营养化，这些结果表明具有含氮结构的简单 OM 的输入更大。EOMSed 中的类腐殖质成分在两条河流中含量最高。来自皮拉西卡巴河的 EOMS 的芳香性通过以芳香族和多芳香族部分以及更高的 SUVA ₂₅₄形式的复杂结构的更大贡献来证明。由于微生物衍生产品的更大贡献以及小分子和含氮结构的存在，来自铁特河的 EOMS 还具有增强的生物活性。由于这种元素和光谱技术的结合成功地确定了提取的 OM 的特征，因此可以将其用作评估全球河流质量的工具。