Analysis And Evaluation Of Water Chemistry And Heavy Metals In The Main Stream Of Xinsui River

Suzhou city is located in Huaibei Plain.As a typical coal-type city and agricultural city,its regional geology,human activities and natural factors all have an impact on the water quality of Xinsui river in Suzhou Basin.This study took Xinsui river in Suzhou Section as the research object,and discussed the water chemical index and the distribution characteristics of heavy metals in the water of Xinsui river based on the measured data of water samples in wet period and dry period of the same year.Correlation analysis,principal component analysis and positive matrix factorization model were used to analyze the sources of water pollution.The improved Nemerow index method,heavy metal pollution index method and irrigation suitability evaluation method were used to evaluate the environmental pollution status of lost river,which could provide theoretical support for regional river management.The main conclusions were as follows:（1）Through the analysis of the chemical index of Xinsui river,the average content of each chemical index was lower in wet season than in dry season.The cation concentration was Ca²⁺>Na⁺>Mg²⁺>K⁺in wet season and Na⁺>Mg²⁺>Ca²⁺>K⁺in dry season.The change of anion content was HCO₃^->SO₄^2->Cl^->F^-.The concentrations of TN,NH₄⁺-N and NO₃^--N were higher in the middle reaches,while the concentrations of other indexes decreased along with the direction of runoff.Through the analysis of the conventional ionic water chemical type of water,it was found that the water chemical type is HCO₃^--Ca²⁺type,which was mainly dominated by rock weathering.The hydrochemical type of the dry period is HCO₃^--Na⁺-K⁺type,which was mainly affected by weathering of rocks,evaporation and crystallization,and human activities.According to the correlation analysis of water chemical indexes,the concentration of most water chemical parameters was mainly affected by rock weathering and dissolution and human activities.Positive matrix factorization model was used to analyze the agricultural non-point source pollution,the effects of hydrogeochemical evolution,urban and rural domestic sewage pollution and industrial pollution.And agricultural non-point source pollution,urban and rural sewage pollution,aquaculture wastewater pollution,hydrogeochemical evolution,industrial pollution five pollution sources.（2）The mass concentration analysis of 9 heavy metals in Xinsui river showed that the concentration changes of As,Cr,Mn,Ni and Fe were in wet period<dry period,while Cu,Zn,Pb and Cd were opposite.The order of heavy metal concentration in wet season is Fe>Mn>As>Zn>Cu>Ni>Cr>Pb>Cd.In the dry season,the pattern was Fe>Mn>As>Cr>Ni>Zn>Cu>Pb>Cd.In dry season,the concentration of As,Cr,Ni,Mn,Ni,Fe and Zn was in the upper reaches>middle reaches>lower reaches.The spatial variation of mass concentration in wet season was not obvious.Among them,the mass concentration of Fe,Mn,As and Cr exceeded the standard,and the coefficient of variation was large.Correlation analysis and principal component analysis were used to analyze the sources of heavy metals.It was found that there were four pollution sources in wet season,namely industrial pollution,natural background value,agricultural non-point source pollution and animal husbandry pollution,and three pollution sources in dry season,namely industrial pollution,natural source pollution and agricultural non-point source pollution.The positive matrix factorization model was used to analyze the sources of heavy metals,and five pollution sources were identified as industrial pollution,agricultural non-point source pollution,urban and rural domestic sewage pollution,traffic pollution and natural background value.There were four sources of pollution in dry season:industrial production pollution,agricultural non-point source pollution,urban and rural domestic wastewater pollution and natural background value.The two methods differed slightly in the source analysis of heavy metal pollutants.（3）Through the selection of characteristic pollutants,a variety of targeted evaluation methods were determined to evaluate the environment of new lost river in various aspects.The results of the improved Nemerow pollution index evaluation showed that the weight of TP was the highest,and the calculation result of the improved Nemerow pollution index was 1.42 in wet season and 2.02 in dry season.All of them belonged to class IV water,which met the requirements of Anhui water function zoning.The water quality in wet season was better than that in dry season.The suitability evaluation of irrigation water showed that the water samples in the study area were in the middle salt and low alkali area,the middle salt and low alkali area,the high salt and low alkali area,and the high salt and middle alkali area.The water samples in the dry season were in the middle-salt and middle-alkali area,the high-salt and low-alkali area,the high-salt and middle-alkali area,and the high-salt and high-alkali area.Therefore,it could be seen that the river water is suitable for irrigation of plants with strong salt and alkaline tolerance,and appropriate measures should be taken to prevent alkali damage.The evaluation of heavy metal pollution index showed that the mean value of HPI in wet season was 13.36,indicating low pollution and 4 sampling points of high pollution;the mean value of HPI in dry season was 25.49,indicating moderate pollution and 10 sampling points of high pollution.The heavy metal pollution index in wet season was less than that in dry season.It was particularly important to carry out research on regional heavy metal detection for the prevention and control of heavy metal pollution.Figure[23]Table[11]Reference[125]...