Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for es...Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for estimating organic matter(OM)composition,and can thus serve as a proxy for conventional chemical oxygen demand(COD_(Mn))measurements,which are considered as imprecise and environmentally unfriendly.Hence,we conducted a field campaign across 30 lakes in Wuhan's metropolitan area,collecting 255 samples from varying trophic states to evaluate the predictive capability of COD_(Mn)using DOM optical measurements combined with parallel factor(PARAFAC)analysis.The DOM optical properties and chemical composition exhibited considerable variability across varying trophic state levels(TSLs).Fluorescence components C1-C3 and C5,fluorescence index(FI),and absorption at 254 nm(α_(254)),increased as TSL increased,while the DOM spectral slope(SR)decreased.COD_(Mn)was positively and significantly correlated with fluorescence components C1-C3 and C5,freshness index(β/α),autochthonous index(BIX),humification index(HIX),α_(254),the ratio ofα_(250)toα_(365)(E2/E3)while being negatively correlated with SR.Parametersα_(254),C1,C3,C4,FI,β/α,and HIX were identified as key predictors of COD_(Mn).The multiple linear regression model successfully predicted COD_(Mn)(r^(2)=0.63,p<0.01,n=1113)and demonstrated superior performance in mesotrophic lakes.These findings highlight the potential for establishing high-frequency,continuous,and multi-regional COD monitoring programs.展开更多
The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how ...The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how dissolved organic matter(DOM)transformation regulates the aquatic As concentrations.The present study revealed that the DOM components from the Singe Tsangpo River(STR)basin primarily consisted of protein-like components(81.30%±6.48%),with the microbially-endogenous production being a predominant source under the control of temperature and glacier-runoff recharge along the river flow path.Notably,the chemical weathering processes have significantly facilitated the enhancement of humic-like components in the river water.Besides,the groundwater DOM characteristics were predominantly influenced by the mobilization of sedimentary organic matter and the introduction of allochthonous DOM resulting from surface-water recharge.Interestingly,humic-like components facilitated As enrichment through complexation and competitive adsorption effects in both surface water and groundwater under oxidizing conditions,whichwas supported by the significant positive correlations between As and humiclike component(R^(2)=0.31/0.65,P<0.05/0.01)and the concurrent mobilization of As and humic-like components from sediment incubation experiments.Moreover,the Structural Equation Modeling analysis revealed a stronger contribution of humic-like components to the As enrichment in the groundwater compared with surface water,possibly due to the relatively strongermicrobial activity and enhanced mobilization of humic-like components in alluvial aquifers.The present study thus provided new insights into the transformation of DOM and its important role in facilitating As enrichment in the aquatic environment from alpine river basins.展开更多
基金This study was funded by Wuhan Institute of Technology(Grant Nos.24QD26,21QD02,22QD64)National Natural Science Foundation of China(Grant No.32102823).
文摘Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for estimating organic matter(OM)composition,and can thus serve as a proxy for conventional chemical oxygen demand(COD_(Mn))measurements,which are considered as imprecise and environmentally unfriendly.Hence,we conducted a field campaign across 30 lakes in Wuhan's metropolitan area,collecting 255 samples from varying trophic states to evaluate the predictive capability of COD_(Mn)using DOM optical measurements combined with parallel factor(PARAFAC)analysis.The DOM optical properties and chemical composition exhibited considerable variability across varying trophic state levels(TSLs).Fluorescence components C1-C3 and C5,fluorescence index(FI),and absorption at 254 nm(α_(254)),increased as TSL increased,while the DOM spectral slope(SR)decreased.COD_(Mn)was positively and significantly correlated with fluorescence components C1-C3 and C5,freshness index(β/α),autochthonous index(BIX),humification index(HIX),α_(254),the ratio ofα_(250)toα_(365)(E2/E3)while being negatively correlated with SR.Parametersα_(254),C1,C3,C4,FI,β/α,and HIX were identified as key predictors of COD_(Mn).The multiple linear regression model successfully predicted COD_(Mn)(r^(2)=0.63,p<0.01,n=1113)and demonstrated superior performance in mesotrophic lakes.These findings highlight the potential for establishing high-frequency,continuous,and multi-regional COD monitoring programs.
基金supported by the National Natural Science Foundation of China(No.42107094)Sichuan Science and Technology Program(No.2023NSFSC0806)the Geology Bureau project of Xinjiang Uygur Autonomous Region(Nos.XGMB202356 and XGMB202358).
文摘The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how dissolved organic matter(DOM)transformation regulates the aquatic As concentrations.The present study revealed that the DOM components from the Singe Tsangpo River(STR)basin primarily consisted of protein-like components(81.30%±6.48%),with the microbially-endogenous production being a predominant source under the control of temperature and glacier-runoff recharge along the river flow path.Notably,the chemical weathering processes have significantly facilitated the enhancement of humic-like components in the river water.Besides,the groundwater DOM characteristics were predominantly influenced by the mobilization of sedimentary organic matter and the introduction of allochthonous DOM resulting from surface-water recharge.Interestingly,humic-like components facilitated As enrichment through complexation and competitive adsorption effects in both surface water and groundwater under oxidizing conditions,whichwas supported by the significant positive correlations between As and humiclike component(R^(2)=0.31/0.65,P<0.05/0.01)and the concurrent mobilization of As and humic-like components from sediment incubation experiments.Moreover,the Structural Equation Modeling analysis revealed a stronger contribution of humic-like components to the As enrichment in the groundwater compared with surface water,possibly due to the relatively strongermicrobial activity and enhanced mobilization of humic-like components in alluvial aquifers.The present study thus provided new insights into the transformation of DOM and its important role in facilitating As enrichment in the aquatic environment from alpine river basins.
文摘采用三维荧光-平行因子法(3D EEMs-PARAFAC)解析了厌氧-缺氧-好氧(A^(2)O)污水生物处理过程中DOM特征,并对各工艺单元生成的N_(2)O进行了定量分析,之后运用机器学习模型对二者的变化关系进行了响应预测.结果表明,污水处理厂进水中DOM主要包含类色氨酸C1,类富里酸C2,类腐殖酸C3和类酪氨酸C4四种组分,并以C1和C4为主,且各组分含量沿污水处理流程逐渐降低,易生物降解的C1和C4的去除速率明显高于C2和C3.N_(2)O排放是直接碳排放的主要组成部分,其变化表现出明显的空间异质性,各处理单元N_(2)O生成总量由高到低依次为好氧池、辐流沉淀池、缺氧池、厌氧池、细格栅、钟式沉砂池.Shapley Additive ex Planation(SHAP)分析表明,C1和C2对N_(2)O生成影响较大,而C3和C4几乎没有影响,其中C1对N_(2)O的生成表现出促进作用,C2则不利于N_(2)O的生成.高通量测序结果表明,能够利用易生物降解有机物进行反硝化的Methylotenera和Terrimonas是污水处理厂内的优势菌属.本研究揭示了A^(2)O污水生物处理过程中N_(2)O生成对不同DOM组分的差异性响应,并为完善当前污水处理厂的碳排放核算方法并优化污水处理厂低碳运行工艺提供了理论支撑.
