Subtropical urban turfs: Carbon and nitrogen pools and the role of enzyme activity

Urban grasslands not only provide a recreational venue for urban residents, but also sequester organic carbon in vegetation and soils through photosynthesis, and release carbon dioxide through respiration, which largely contribute to carbon storage and fluxes at regional and global scales. We investigated organic carbon and nitrogen pools in subtropical turfs and found that dissolved organic carbon(DOC) and dissolved organic nitrogen(DON)were regulated by several factors including microbial activity which is indicated by soil enzymatic activity. We observed a vertical variation and different temporal patterns in both soil DOC, DON and enzyme activities, which decreased significantly with increasing soil depths. We further found that concentration of soil DON was linked with turf age. There were correlations between grass biomass and soil properties, and soil enzyme activities. In particular, soil bulk density was significantly correlated with soil moisture and soil organic carbon(SOC). In addition, DOC correlated significantly with DON. Significant negative correlations were also observed between soil total dissolved nitrogen(TDN) and grass biomass of Axonopus compressus and Zoysia matrella. Specifically, grass biomass was significantly correlated with the soil activity of urease and β-glucosidase. Soil NO3-N concentration also showed negative correlations with the activity of both β-glucosidase and protease but there were no significant correlations between cellulase and soil properties or grass biomass. Our study demonstrated a relationship between soil C and N dynamics and soil enzymes that could be modulated to enhance SOC pools through management and maintenance practices.     

廊坊市开发区冬季颗粒物碳组分污染特征及来源分析

廊坊市是北京市及周边传输通道“2+26”城市之一.为研究廊坊市开发区冬季颗粒物中碳组分污染特征,于2018年1月5日—2月5日在廊坊市开发区国控点位同步开展PM_2.5及PM₁₀样品采集,使用DRI分析OC（有机碳）与EC（元素碳）的质量浓度.结果表明:廊坊开发区冬季ρ（PM_2.5）、ρ（PM₁₀）分别为（54.5±46.0）（91.0±58.2）μg/m3.PM_2.5中ρ（OC）、ρ（EC）分别为14.64、3.54 μg/m3,PM₁₀中分别为17.07、4.58 μg/m3;PM_2.5、PM₁₀中ρ（OC）与ρ（EC）相关性均较好,R2均为0.91（P < 0.01）,表明二者具有相似的来源;在PM_2.5和PM₁₀中OC/EC〔ρ（OC）/ρ（EC）,下同〕分别为4.46和4.16,ρ（SOC）（SOC为二次有机碳）分别为6.15和5.88 μg/m3,分别占ρ（OC）的42.1%和37.7%,表明二次污染较严重.碳组分丰度及主成分分析结果表明,PM_2.5与PM₁₀中碳组分来源基本一致,主要来源于汽车尾气、水溶性极性化合物、生物质燃烧及燃煤的混合源,柴油车排放,以及道路扬尘.后向气流轨迹聚类结果表明,颗粒物及碳组分质量浓度受途径内蒙古自治区及河北省中部、北京市南部气团的影响较大;对于碳组分来源,道路扬尘及汽车尾气受气团传输的影响较大,而生物质燃烧、燃煤等受气团传输的影响较小.研究显示,汽车尾气、燃烧源及道路扬尘为廊坊市开发区冬季碳组分的主要来源.      

Characterization of dissolved organic matter and membrane fouling in coagulation-ultrafiltration process treating micro-polluted surface water

Coagulation–ultrafiltration(C–UF) is widely used for surface water treatment. With the removal of pollutants, the characteristics of organic matter change and affect the final treatment efficiency and the development of membrane fouling. In this study, we built a dynamic C–UF set-up to carry out the treatment of micro-polluted surface water, to investigate the characteristics of dissolved organic matter from different units. The influences of poly aluminum chloride and poly dimethyldiallylammonium chloride(PDMDAAC) on removal efficiency and membrane fouling were also investigated. Results showed that the dosage of PDMDAAC evidently increased the UV254 and dissolved organic carbon removal efficiencies,and thereby alleviated membrane fouling in the C–UF process. Most hydrophobic bases(HoB)and hydrophobic neutral fractions could be removed by coagulation. Similarly, UF was good at removing HoB compared to hydrophilic substances(HiS) and hydrophobic acid(HoA)fractions. HiS and HoA fractions with low molecule weight accumulated on the surface of the membrane, causing the increase of transmembrane pressure(TMP). Membrane fouling was mainly caused by a removable cake layer, and mechanical cleaning was an efficient way to decrease the TMP.     

氧化物涂层砂对天然水中有机物的去除

氧化物涂层砂,比表面积增加,吸附容量增大,使石英砂表面电荷的带电性质改变,有利于水中天然有机物的去除。对3种不同氧化物涂层砂和未涂层砂对天然有机物的去除性能进行了比较实验,证明涂铝砂和B型涂铁砂对水中天然有机物的去除效果优于A型涂铁砂;而3种涂层砂均优于未涂层砂。     

堆肥处理过程中猪粪有机物的动态变化特征

为了解猪粪堆肥过程中各种有机物的变化特征,并为判断猪粪堆肥腐熟度提供参考指标,进行42d的高温好氧堆肥.结果表明,堆体中的有机质含量呈下降趋势;水溶性有机碳(DOC)含量在第10d达到最大值,之后呈下降趋势;易分解有机质含量呈下降趋势,但在高温开始阶段呈上升趋势;腐殖质含量呈上升趋势.说明堆肥过程中有机物不断向腐殖化方向转化.在研究H/F变化时发现,它与判断堆肥腐熟度常用的化学指标(有机质、DOC)呈一定的相关性,而且与易分解有机质和腐殖质也有较好的相关性.     

Characterisation of dissolved organic matter in stormwater using high-performance size exclusion chromatography

Understanding the complexity of dissolved organic matter(DOM)in stormwater has drawn a lot of interest,since DOM from stormwater causes not only environmental impacts,but also worsens downstream aquatic quality associated with water supply and treatability.This study introduced and employed high-performance size exclusion chromatography(HPSEC)coupled with an ultraviolet–visible(UV–vis)diode array detector to assess changes in stormwater-associated DOM characteristics.Stormwater DOM was also analysed in relation to storm event characteristics,water quality and spectroscopic analysis.Statistical tools were used to determine the correlations within DOM and water quality measurements.Results showed that dissolved organic carbon(DOC)and UV absorbance at 254 nm(UV_(254))as conventional DOM parameters were found to be correlated well to the changes in stormwater quality during each of the three storm events studied.Both detector wavelengths(210and 254 nm)and their ratio(A_(210)/A_(254))were found to provide additional information on the physiochemical properties of stormwater-associated DOM.This study indicated that A_(210)/A_(254) is an important parameter which could be used to estimate the DOM proportions of functional groups and conjugated carbon species.This study provided also an understanding of stormwater quality constituents through assessing variability and sensitivity for various parameters,and the additional information of rainfall characteristics on runoff quality data for a better understanding of parameter correlations and influences.     

The migration and transformation of dissolved organic matter during the freezing processes of water

This study investigated the partitioning behavior of dissolved organic matter (DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the increase in dissolved organic carbon (DOC) concentration of feed water, caused an increase in DOM captured in the ice phase. The ultraviolet-absorbing compounds, trihalomethane precursors, as well as fulvic acid- and humic acid-like fluorescent materials, were more liable to be to be rejected from the ice phase and were more easily retained in the unfrozen liquid phase during water freezing, as compared with organics (on average) that comprise DOC. In addition, it was also found a higher accumulation of these organics in the unfrozen liquid phase during water freezing at higher temperature. The freeze/thaw processes altered the quantity, optical properties, and chlorine reactivity of DOM. The decrease in ultraviolet light at 254 nm as well as the production of aromatic protein- and soluble microbial byproduct-like fluorescent materials in DOM due to freeze/thaw were consistently observed. On the other hand, the changes in DOC, trihalomethane formation potential, and fulvic acid- and humic acid-like fluorescence caused by freeze/thaw varied significantly between samples.     

活性炭对天然水体中甲基对硫磷和三氯乙烯的吸附特性研究

采用序批式试验研究了3种粉末活性炭(PAC)对天然水体中甲基对硫磷(MP)和三氯乙烯(TCE)的吸附平衡特性,利用均相表面扩散模型(HSDM)对不同投炭量下的吸附动力学进行拟合与预测,并探讨了天然有机物(NOM)对MP、TCE在PAC上的竞争吸附效应.研究结果表明,天然水体条件下,3种PAC对MP和TCE的吸附符合Langmuir模型和Freundlich模型;MP比TCE更易于被PAC吸附;3种PAC对MP、TCE的吸附能力由大到小依次为YK炭、SL炭和JC炭;HSDM模型可以很好地对吸附动力学进行拟合,并能够有效地预测不同投炭量时的吸附动力学;天然水体中的NOM会与MP和TCE在PAC上发生竞争吸附,NOM对MP的竞争吸附作用相对TCE更为显著.     

唐山市大气颗粒物OC/EC浓度谱分布观测研究

华北重工业城市唐山大气颗粒物污染严重,2009～2011年PM1.1、PM2.1、PM9.0及TSP年均值分别为(75±43)、(106±63)、(221±100)和(272±113)μg.m-3;碳质气溶胶在各粒径段均占较大比重,其中,元素碳(EC)在PM1.1、PM2.1、PM9.0及TSP各粒径段的年均比重分别约为9%、9%、6%和4%,有机碳(OC)年均比重分别为25%、24%、16%和14%.颗粒物浓度谱分布及碳质气溶胶富集量呈显著季节变化,秋冬季节细颗粒物中EC和OC浓度可高达(9±4)、(11±5)和(19±7)、(28±10)μg.m-3,分别占PM2.1的11%、10%和26%、25%;春夏季节EC和OC在粗细粒子中的富集量基本相当,分别为(5±2)、(5±1)和(15±3)、(15±1)μg.m-3,分别约占颗粒物总量的7%、6%和26%、18%.     

机动车源和民用燃料源颗粒物中有机碳和元素碳的排放特征

为了获取机动车源尾气和主要民用燃料源燃烧过程排放的颗粒物中含碳气溶胶的排放特征,使用多功能便携式稀释通道采样器和Model 5L-NDIR型OC/EC分析仪,采集分析了典型机动车源(汽油车、轻柴油车、重柴油车)、民用煤(块煤和型煤)和生物质燃料(麦秆、木板、葡萄树树枝)的PM₁₀和PM_2.5样品中的有机碳(OC)和元素碳(EC).结果表明,不同排放源释放的PM₁₀和PM_2.5中含碳气溶胶的质量分数存在显著差异.总碳(TC)在不同源PM₁₀和PM_2.5中的质量分数范围分别为40.8%～68.5%和30.5%～70.9%,OC/EC范围分别为1.49～31.56和1.90～87.57.不同源产生的含碳气溶胶均以OC为主,OC在PM₁₀和PM_2.5中的质量分数范围分别为56.3%～97.0%和65.0%～98.7%.在PM₁₀和PM_2.5的含碳气溶胶中OC质量分数按照从高到低...     

Occurrence, polarity and bioavailability of dissolved organic matter in the Huangpu River, China

Dissolved organic matter （DOM） plays an important role in biogeochemical cycles in aquatic ecosystem. To investigate the characteristics of DOM in Huangpu River {the last tributary of the Yangtze River）, surface water samples were collected along the river from December 2011 to June, 2013. The concentrations of dissolved organic carbon （DOC）, the absorbance and fluorescence spectrum of DOM in water samples were measured. Fluorescent DOM in the Huangpu River was decomposed into four components by the parallel factor analysis （PARAFAC）, including one humic-like substance and three protein-like substances. It showed that high spatial variability of DOC concentration was observed in the upstream water compared to the downstream water, and so did the absorbance coefficients of chromophoric dissolved organic matter and the total fluorescence intensities of different PARAFAC components of DOM. Furthermore, there was a large difference between the polarity and bioavailability of DOM in the Huangpu River. Polar compounds dominated tyrosine-like component of fluorescent DOM in all seasons. Tryptophan-like and humic-like substances had more polar fraction in summer and autumn than those in winter, while aromatic protein-like materials had the highest polar fraction in winter. Almost all of fluorescent DOM components were refractory in spring, while less than 20% of fluorescent DOM in average were biodegradable within 4 weeks in other seasons. We concluded that the spatial variation in the abundance of DOM in the Huangpu River is mainly affected by the water discharges from the Hangjiahu Plain and the seasonal difference in polarity and bioavailability of DOM is largely determined by its origins.     

Effects of chemical modification on physicochemical properties and adsorption behavior of sludge-based activated carbon

This study aimed to explore the adsorption performance of sludge-based activated carbon (SBC) towards dissolved organic matters (DOMs) removal from sewage, and investigated the modification effect of different types of chemicals on the structure of synthesized SBC. Waste activated sludge (WAS) was used as a carbon source, and HCl, HNO₃, and NaOH were used as different types of chemicals to modify the SBC. With the aid of chemical activation, the modified SBC showed higher adsorption performances on DOMs removal with maximum adsorption of 29.05 mg/g and second-order constant (k) of 0.1367 (L/mol/sec) due to the surface elution of ash and minerals by chemicals. The surface elemental composition of MSBC suggested that the content of C-C and C-O functional groups on the surface of modified sludge-based activated carbon (MSBC) played an important role on the adsorption capacities of MSBC towards DOMs removal in sewage. Additionally, the residual molecular weight of DOMs in sewage was investigated using a 3-dimension fluorescence excitation-emission matrix (3D-EEM) and high-performance size exclusion chromatography (HP-SEC). Results showed that the chemical modification significantly improved the adsorption capacity of MSBC on humic acids (HA) and aromatic proteins (APN), and both of NaOH-MSBC and HCl-MSBC were effective for a wide range of different AMW DOMs removal from sewage, while the HNO₃-MSBC exhibited poorly on AMW organics of 2,617 Da and 409 Da due to the reducing content of macropore. In brief, this study provides reference values for the impact of the chemicals of the activation stage before the SBCs application.     

Impact of carbon-based nutrient enhancement on biofiltration performance for drinking water treatment

Incorporation of a carbon-based nutrient enhancement strategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids (including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon (DOC) in the source water, including disinfection by-product (DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate (ATP), dissolved oxygen (DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss, turbidity, pH, DOC, UV₂₅₄, and DBP formation potential (DBP FP). The introduction of carbon-based nutrients significantly increased biomass activity, where ATP values peaked at 976?ng/g of filter media, 853?ng/g, and 513?ng/g for amino acids, inulin, and sucrose-spiked biofilters, respectively, while a non-spiked control only reached 104?ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters (R²?>?0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated (p?> 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal (DOC and UV₂₅₄) or DBP FP when treated filters were compared to a control.     

太湖北部湖区春、冬季节天然有机质的荧光特征及环境意义

天然有机质(OM)广泛存在于各类水体,含有丰富的碳、氮、磷等生源要素,其形成、转化、归宿及其相伴随的营养盐再生过程是水生态系统营养盐生物地球化学循环的重要环节,在湖泊蓝藻水华暴发过程中势必也扮演着非常重要的营养盐供给者的角色.本研究于2015年2月和5月分别在太湖北部湖区采集了17个样品,利用POM-DOM PARAFAC三维荧光模型解析春、冬季节颗粒态有机质(POM)和溶解态有机质(DOM)的荧光特征及来源,并探讨POM和DOM各荧光组分之间及其与叶绿素a(Chla)的关系.结果表明,春、冬季节太湖北部湖区POM和DOM的荧光峰、荧光中心位置和荧光强度均存在明显的差别;POM有着比DOM更复杂的组分构成.综合POM和DOM的荧光强度和荧光指数可知,春、冬季节太湖北部湖区POM和DOM均以自生源为主,河口区受陆源贡献较大.POM(C1p~C5p)和DOM(C1d~C5d)有5种荧光组分,分别是类色氨酸(C1和C2)、类腐殖质(C3和C4)及类酪氨酸(C5).POM和DOM的荧光组分特征存在明显的差别;春、冬季节POM均以类腐殖质荧光C3为主,荧光组分高值区分别集中在梅梁湾区域和湖心区;而DOM均以类蛋白组分C2、C1和C5为主,荧光组分高值区均分布在竺山湾区域.相关分析结果显示,春季C1d与C2d(P0.01)、C3d与C4d(P0.01)、C1p与C4p(P0.05)、C2p与C5p(P0.01)均具有较强的相关性.值得注意的是,C3d(P0.01)、C4d(P0.05)与C3p均具有较好的相关关系,表明POM与DOM在组分、来源上具有某种联系.与春季类似,冬季荧光组分C1d与C2d、C3d与C4d、C1p与C2p、C1d与C2p亦具有极好的相关性(P0.01).春季C5d与Chla之间存在正相关关系(P0.01),而C2d(P0.05)、C3p(P0.01)与Chla之间具有负相关关系;冬季C4d与Chla之间也存在负相关关系(P0.05).     

水环境中溶解性有机物溯源分析及分子结构表征概述

溶解性有机物(DOM)是地球上最大的碳基化合物反应性储层之一,涉及各种生物地化反应并且在污染物溶解度、毒性、生物利用度、流变性和分布中发挥重要作用。本文介绍了当前用于表征水环境中DOM的策略和工具,探讨了当前研究在技术限制(预处理过程复杂、仪器分辨率低、数据处理困)、结构复杂性、结构多变性等方面存在的诸多局限性。分析认为:已有研究主要侧重于溯源分析和分子结构特征解析,未来研究应该在不同的结构层面和角度开展,加强多学科融合、数据库创建、对照实验和协同工作。     

水体有色溶解有机质的研究进展

有色溶解有机质（CDOM）是溶解有机质（DOM）的重要组成部分,它影响着碳的生物地球化学循环,为水生微生物提供重要的碳源和能源。文章介绍了国内外CDOM的研究进展和动态．主要包括CDOM的紫外吸收光谱研究,荧光光谱研究,并对CDOM中主要成分的荧光峰位置及峰值变化、来源进行论述．最后对CDOM的研究重点作了展望。     

三江平原湿地土壤活性有机碳组分特征及其与土壤酶活性的关系

对三江平原3种主要类型天然湿地(毛苔草湿地、小叶章湿地、岛状林湿地)O-20cm土壤活性有机碳(土壤微生物量碳、土壤可溶性有机碳)特征进行了研究,分析了不同湿地的土壤活性有机碳与土壤总有机碳及酶活性间的关系.结果表明:不同类型湿地的土壤活性有机碳组分含量存在较大的差异,土壤活性有机碳、土壤总有机碳及土壤脲酶、蔗糖酶、淀粉酶、过氧化氢酶的变化趋势具有基本近似的特征.表现为毛苔草湿地>小叶章湿地>岛状林湿地;土壤微生物量碳、可溶性有机碳与土壤总有机碳和酶活性存在显著正相关关系,其中,酶活性与土壤微生物量碳相关性最为显著.另外.毛苔草湿地土壤MBC/SOC、DOC/SOC的比值低于其它2种类型湿地,表明毛苔草湿地生物活性有机碳库的周转速率低.淹水抑制了微生物和酶的分解作用,有利于土壤有机碳的累积.因此,沼泽湿地水文条件的变化将会对土壤碳累积与分解过程产生较大的影响.     

太湖典型草、藻型湖区有色可溶性有机物的吸收及荧光特性

2004年4月对太湖典型草、藻型湖区东太湖和梅梁湾有色可溶性有机物(CDOM)的吸收和荧光特性进行了研究.通过实验测定方法得到东太湖和梅梁湾CDOM的光谱吸收系数及其荧光值.结果表明,溶解性有机碳(DOC)的浓度在6.3～17.2 mg/L间变化,其均值为9.08±2.66 mg/L;CDOM在280 nm和355 nm的吸收系数分别为11.2～32.6 m^-1(平均值17.46m-1±5.75 m^-1)和2.4m～8.3 m^-1(平均值4.17 m^-1±1.47 m^-1);355 nm波长处CDOM的比吸收系数为0.31～0.64 L·(mg·m)^-1,平均值0.46L·(mg·m)^-1±0.08 L·(mg·m)^-1.355 nm的激发波长、450 nm的发射波长处的荧光值的变化范围0.50～3.91 nm^-1(平均值1.32nm-1±0.84 nm^-1).2类草、藻型湖区的DOC浓度、CDOM吸收系数、355 nm处荧光值均存在显著性差异,但CDOM比吸收系数和指数函数斜率则没有显著性差异,由此则反映了CDOM来源的一致性.CDOM的吸收系数与DOC浓度的相关性随波长的降低而增加,在短波部分存在明显的正相关.355 nm处的荧光值、DOC浓度与CDOM吸收系数存在如下显著性的正相关关系:F_n(355)=0.544(±0.035)a(355)-0.946(±0.152),DOC=1.537(±0.196)a(355)+2.683(±0.862).280～500 nm、280～360 nm、360～440 nm指数函数斜率分别为14.37μm^-1±0.73μm^-1、19.17μm-1±0.84μm^-1、13.38μm-1±0.82μm^-1.     

Mercury photoreduction and photooxidation in lakes: Effects of filtration and dissolved organic carbon concentration

Mercury is a globally distributed, environmental contaminant. Quantifying the retention and loss of mercury is integral for predicting mercury-sensitive ecosystems. There is little information on how dissolved organic carbon(DOC) concentrations and particulates affect mercury photoreaction kinetics in freshwater lakes. To address this knowledge gap,samples were collected from ten lakes in Kejimkujik National Park, Nova Scotia(DOC: 2.6–15.4 mg/L). Filtered(0.2 μm) and unfiltered samples were analysed for gross photoreduction, gross photooxidation, and net reduction rates of mercury using pseudo first-order curves. Unfiltered samples had higher concentrations(p = 0.04) of photoreducible divalent mercury(Hg(II)RED)(mean of 754 ± 253 pg/L) than filtered samples(mean of 482 ± 206 pg/L);however, gross photoreduction and photooxidation rate constants were not significantly different in filtered or unfiltered samples in early summer. DOC was not significantly related to gross photoreduction rate constants in filtered(R~2= 0.43; p = 0.08) and unfiltered(R~2= 0.02; p = 0.71) samples; DOC was also not significantly related to gross photooxidation rate constants in filtered or unfiltered samples. However, DOC was significantly negatively related with Hg(Ⅱ)_(RED) in unfiltered(R2= 0.53; p = 0.04), but not in filtered samples(R~2= 0.04;p = 0.60). These trends indicate that DOC is a factor in determining dissolved mercury photoreduction rates and particles partially control available Hg(Ⅱ)_(RED) in lake water. This research also demonstrates that within these lakes gross photoreduction and photooxidation processes are close to being in balance. Changes to catchment inputs of particulate matter and DOC may alter mercury retention in these lakes and could partially explain observed increases of mercury accumulation in biota.     

Revealing the characteristics of dissolved organic matter in urban runoff at three typical regions via optical indices and molecular composition

Dissolved organic matter (DOM) plays a major role in ecological systems and influences the fate and transportation of many pollutants. Despite the significance of DOM, understanding of how environmental and anthropogenic factors influence its composition and characteristics is limited, especially in urban stormwater runoff. In this article, the chemical properties (pollutant loads, molecular weight, aromaticity, sources, and molecular composition) of DOM in stormwater extracted from three typical end-members (traffic, residential, and campus regions) were characterized by UV–visible (UV–vis) spectroscopy, excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC), and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). There are three findings: (1) The basic properties of DOM in stormwater runoff varied obviously from three urban fields, and the effect of initial flush was also apparent. (2) The DOM in residential areas mainly came from autochthonous sources, while allochthonous sources primarily contributed to the DOM in traffic and campus areas. However, it was mainly composed of terrestrial humic-like components with CHO and CHON element composition and HULO and aliphatic formulas. (3) The parameters characterizing DOM were primarily related to terrestrial source and aromaticity, but their correlations varied. Through the combination of optical methods and UPLC-Q-TOF spectrometry, the optical and molecular characteristics of rainwater are effectively revealed, which may provide a solid foundation for the classification management of stormwater runoff in different urban regions.