Study On DOM Content Distribution,Component Characteristics And Pollution Indication Effect Of River Water In Changzhutan Section Of Xiangjiang River Basin

Dissolved organic matter(DOM)has strong reactivity and is one of the causes of water pollution.Its content is generally expressed as dissolved organic carbon(DOC).Dissolved organic carbon(DOC)is of river organic carbon.The main component is also an important indicator of river pollution.Therefore,the research on the content,structure and composition of dissolved organic matter in the water body of the Changzhutan section of the Xiangjiang River Basin has certain guiding significance for the changes of the water environment of the river basin and the monitoring and early warning effects.Based on this,this study took the river DOM of the important urban agglomeration of the Xiangjiang River Basin(Zhuzhou-Changsha section)as the research object.In February 2019,systematically sampled the characteristic sample points of different river sections.Using methods such as along-course analysis,correlation analysis,and regression analysis,the spatial distribution characteristics of DOC and their relationship with other water quality indicators were discussed.On this basis,by three-dimensional fluorescence spectroscopy and parallel factor analysis,the composition and content distribution characteristics of DOM in the Changzhutan section of the Xiangjiang River Basin were analyzed,and the fluorescence spectrum characteristics of DOM in river waters were analyzed by peak finding In order to explore the distribution characteristics and sources of DOM under different spatial changes,and the role of water pollution,the relevant research shows:(1)The research results of the water quality distribution of the river reach indicate that the main water quality indicators along the river generally show the trend of the main stream water quality indicators rising first,then decreasing and finally stabilizing,while the tributaries of the river reach Baishi Port Inner River and Zhubu Port Drainage Channel.The water quality has certain pollution characteristics,and the index value is significantly higher than that of other river bodies.The results of spatial cluster analysis show that the river basin samples can be roughly divided into 2 types and 4 groups,of which the water quality of the sampling points of the first and fourth groups is poor,followed by the second group,and the sampling points of the third group represent Water quality in other areas is better.Taken together,the samples withpoor water quality are located in the Baishi Port Inland River,Zhubu Port Drainage Channel and Xiawan District River.This section is mainly affected by human activities and may be affected by domestic sewage and industrial wastewater.The pollution load is relatively heavy;the sample points of the river section with better water quality are the upstream of the main stream of the Xiangjiang River(Changsha Section)and the tributaries of the Laodao River,indicating that the main stream of the Xiangjiang River has better water quality and the main stream is not significantly different,which may be diluted with the main stream pollutants Self-purification and less disturbance of human activities in the upper reach of Laodao River.(2)The spatial distribution characteristics of DOC content show that the DOC content of the main stream varies from 1.23 mg / L to 3.18 mg / L.The average DOC content of the main stream is 2.15 mg / L,which is lower than that of other similar rivers,Indicating that the overall load of DOC content in the reach is small.The results of the river sections in different regions are as follows: Changsha section(mean 2.91 mg / L)> Zhuzhou section(mean 2.04 mg / L)> Xiangtan section(mean1.89 mg / L),the DOC content of tributaries is the mean content of Zhubu Port The highest value is 3.21 mg / L,while the average content of Jinjiang River is the lowest,its value is 1.84 mg / L,which is basically consistent with the results of tributary water quality with different pollution levels.Correlation analysis of DOC and other water quality indicators in the study area shows that the DOC content has a significant correlation with the dissolved oxygen(DO),total phosphorus(TP)and total nitrogen(TN)concentrations,and the potassium permanganate index(CODMn)The low correlation indicates that DOC is mainly affected by human life and has little effect on industrial emissions.Regression analysis shows that DOC and dissolved oxygen(DO),total dissolved solids(TDS),conductivity(EC),total phosphorus(TP),ammonia nitrogen(NH4 +-N),potassium permanganate index(CODMn)Sig value Satisfying Sig <0.05,the regression coefficient is significant,indicating that it has a certain indicator effect on the later water pollution changes and monitoring.(3)Through the analysis of three-dimensional fluorescence spectrum flatness factor and peak-finding method,it is found that there are 4 fluorescent components in the DOM sample of the Changzhutan section of the Xiangjiang River,which are protein-like(tyrosine-like)components and humus-like components.(Visible fulvic acid),protein-like(tryptophan-like)component,humus-like(humic acid-like).The fluorescence intensity of four peaks is: T peak> C peak> F peak> B peak.Thecorrelation analysis between the four components of DOM and the water quality index showed that component C3(peak T is a tryptophan-like fluorescence peak)and component C4(peak B is a tyrosine-like fluorescence peak)and total nitrogen(TN),potassium permanganate index(CODMn)and total phosphorus(TP)have a significant correlation.Protein-like proteins are important sources of total nitrogen(TN)and total phosphorus(TP)in water,and are greatly affected by human activities.(4)The analysis of the two fluorescence spectrum indexes of FI and BIX shows that the DOM of the Changjiang-Zhutan section of the Xiangjiang River has dual sources,namely,endogenous input and terrestrial input.The source is the main source.This feature is derived from the release of microorganisms in the water body,and the characteristics of the autogenous source are high;indicating that the sewage load leads to the release of DOM in the river;the main stream water body is mainly derived from the land source input,from the land plants and soil Nutritional organic matter,as well as domestic,industrial and agricultural sewage.(5)According to the Fn(355)analysis of the DOM of the Changjiang-Zhutan section of the Xiangjiang River,the overall performance of the DOM total fluorescence intensity of the Zhuzhou-Changsha section is: inland discharge>upstream> downstream> midstream;the Xiangjiang River Basin(Changzhutan))(Main and tributary)The overall performance trend of the total DOM fluorescence intensity in the upstream,midstream and downstream is: the trend of declining first in the upstream,slowly rising in the midstream,and steadily decreasing in the downstream.Correlation analysis showed that Fn(355)and dissolved oxygen(DO)in each sampling point of Xiangjiang(Changzhutan)had a strong negative correlation(R =-0.797,P <0.001).The increase of DOM concentration may also cause the decrease of DO One factor;Fn(355)is extremely positively correlated with conductivity(EC),total dissolved solids(TDS),total phosphorus(TP),and ammonia nitrogen(NH4 +-N),indicating that protein-like proteins are nitrogen and phosphorus in water Important sources also indicate that DOM can be used to indicate the study of the degree of organic pollution and water quality in the water body of the Changzhutan section of the Xiangjiang River.