Sources and transformations of dissolved organic matter in urban impervious surface sediments: Insights from optical signatures and environmental drivers

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-06-26 DOI:10.1016/j.watres.2025.124117

Xuan Wang , Jiayi Wang , Jiaxin Yan , Yan Dong , Weizhou Wang , Qi Gao , Xiaojiang Huang , Zhiqiang Zhang , Jinsuo Lu

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Abstract

Despite the critical role of dissolved organic matter (DOM) in urban aquatic environments, knowledge about DOM characteristics in urban impervious surface sediments—a major source of non-point pollution—remains limited. This study addresses this gap by investigating DOM spatiotemporal distribution, sources, and transformation mechanisms through an innovative integration of optical analysis with multidimensional environmental factors. Surface sediment samples (n = 171) were collected across different functional zones and impervious surfaces in Xi'an, China. Three major fluorescent components were identified: UV humic-like C1 predominantly from soil/vegetation, visible-light humic-like C2 mainly from atmospheric deposition, and protein-like C3 primarily from microbial/human activities. Redundancy analysis revealed that meteorological factors, land use, and air quality collectively explained 35.78 % of DOM variability, and structural equation modeling (SEM) further quantified their direct/indirect effects on DOM sources and transformation. Significant seasonal and spatial heterogeneity was observed: dry periods facilitated atmospherically deposited DOM accumulation, while rainfall preferentially washed off soluble low-molecular-weight fractions. Built-up area proportion negatively impacted C1, confirming its natural source origin. Atmospheric pollutants strongly influenced C2 composition and aromaticity, while temperature enhanced microbial processes, promoting C3 formation. These findings provide a scientific foundation for developing targeted non-point source pollution control strategies and deepen our mechanistic understanding of urban DOM cycling in rapidly urbanizing regions.

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城市不透水表层沉积物中溶解有机物的来源和转化：来自光学特征和环境驱动因素的见解

尽管溶解有机物（DOM）在城市水生环境中起着至关重要的作用，但对城市不透水地表沉积物（非点源污染的主要来源）中DOM特征的了解仍然有限。本研究通过创新地将光学分析与多维环境因素相结合，研究DOM的时空分布、来源和转化机制，从而弥补了这一空白。在西安市不同功能区和不透水地表采集了171份地表沉积物样本。鉴定出三种主要荧光成分：主要来自土壤/植被的紫外腐殖质样C1，主要来自大气沉降的可见光腐殖质样C2，主要来自微生物/人类活动的蛋白质样C3。冗余分析表明，气象、土地利用和空气质量共同解释了35.78%的DOM变异，结构方程模型（SEM）进一步量化了它们对DOM来源和转化的直接/间接影响。干旱期促进了大气中DOM的积累，而降雨则优先冲走了可溶性的低分子量组分。建成区面积比例负向影响C1，证实了C1的自然来源。大气污染物强烈影响C2的组成和芳香性，而温度增强了微生物过程，促进了C3的形成。这些发现为制定有针对性的非点源污染控制策略提供了科学依据，并加深了我们对快速城市化地区城市DOM循环机理的理解。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.