Study On The Distribution Characteristics And Influencing Factors Of Fluoride(F~-) In Qingshui River Basin Of Ningxia

The occurrence of fluorine in the environment is the result of long-term geological effects and geochemical evolution.Excessive fluoride has become an important factor affecting the safety of drinking water in arid and semi-arid areas in northern my country.High-fluorine water is a typical inferior water source widely distributed in arid and semi-arid areas in northern my country.Drinking such water for a long time will cause serious harm to the human body.In this paper,the Qingshui River Basin,where humans live in the central and southern regions of Ningxia,is taken as the research scope.The analysis results of the surface water,sediment,and rocks in the Qingshui River Basin are statistically analyzed,spatial and temporal distribution characteristics,hydrochemical characteristics,impact factor analysis,etc.the study.The full text starts from three aspects:spatial and temporal distribution characteristics,geochemical analysis,and the influence of ecological and environmental factors,and discusses the distribution characteristics and influencing factors of fluoride in Qingshui River Basin in Ningxia.The main research conclusions are as follows:(1)In terms of time,compared with the fluoride concentration in different seasons,the highest fluoride in the dry season is 1.83mg/L,the second in the flat season is 0.64mg/L,and the lowest in the wet season is 0.41mg/L.It presents the distribution characteristics of dry season>average water period>abundant water period,reflecting the obvious control effect of rainfall and runoff on fluorine concentration;spatially,in April 2018,it showed the characteristics of fluorine concentration main stream>tributary,downstream>upstream,due to The main stream flow of the river is long.From the upstream semi-humid area to the downstream semi-arid-arid area,the surface evaporation gradually increases,so the downstream river is subjected to strong evaporation-concentration,resulting in increased fluoride(F-)concentration;2018 In July 2015,it showed the characteristics of fluoride concentration tributary>main stream,upstream>downstream.During the flood season,the river is replenished with sufficient water,so that the concentration of fluoride in the surface water drops significantly,and the confluence from the tributary to the main stream is diluted.This is related to the superposition effect produced by the influx of tributaries and the climate of the river basin.(2)The water body of Qingshui River Basin is weakly alkaline and belongs to rivers in arid and semi-arid regions.The order of ion concentration is Na+>Mg2+>K+>Ca2+;SO42->Cl->CO32->HCO3-.The chemical types of surface water in the study area are mainly Na+-K+-SO42-type with high salinity and mixed with Na+-K+-Cl-type.SO42-and Na+ are the dominant ions,followed by K+and Cl-.It is proved that there are weathering products of evaporative rocks(mainly including gypsum and anhydrite rocks,salt rocks,etc.)in the study area;the cluster analysis and correlation analysis results show that the enrichment of fluoride ions and the SO42-,TDS,EC,Cl-The clustering relationship is close,which can become an important factor in studying the enrichment of fluorine.It indicates that the enrichment of fluoride(F-)is genetically related to the Paleogene-Neogene and Cretaceous red layers rich in rock salt and gypsum in the watershed,and the alkaline environment indicated by pH and HCO3-affects it Migration,transformation.(3)According to the pollutant discharge survey data of enterprises,the results show that there are no fluoride-containing companies in the Qingshui River Basin,indicating that the source of fluoride in the basin is not related to human activities.Studies have shown that the formation rock is the material basis for fluoride.The average content of fluoride(F’)in the solid rock in the Sikouzi Reservoir area is 1409 mg/kg,which is higher than the national average,indicating that this area is a high-fluorine background area.Fluorine-containing minerals migrated into the water area by leaching,which caused the fluoride concentration in the study area to increase.The water-soluble fluoride in the sediment of the sediment has a very significant correlation with the surface water,proving that the content of fluorine in the sediment and the surface water The causes are closely linked.For the reservoir effect,due to the vast water surface of the reservoir area,the evaporation is higher than that of the watershed,which will affect the fluoride(F-).