Analysis Of Water Chemistry Characteristics And Source Of Pollutants In The Yarlung Zangbo River Basin In Qinghai-Tibet Plateau

In this paper,the main stream and tributaries of the Yarlung Zangbo River in Tibet are studied to determine the main ion concentrations of the water body in the Yarlung Zangbo River basin during the dry,wet and flat periods.The main ion composition and hydrochemical characteristics of the Yarlung Zangbo River are analyzed.Activity and rock weathering on the hydrochemical environment in the Yarlung Zangbo River Basin and its temporal and spatial variation;and the determination of heavy metal content.Through the above research,draw the following conclusions and understanding:?1?The water body of Yarlung Zangbo River basin was generally alkaline or weak alkaline in dry season,wet season and flat-water period.The TDS ranged from58.60 to 451.00 mg/L with the average concentration of 254.00 mg/L,which was higher than the world average of 100 mg/L,the dry season TDS concentration is greater than the wet period,the conductivity range of 18.50⁶32.00?S/cm,mean252.3?S/cm;dissolved oxygen range of 2.8¹5.5 mg/L,with an average of 10.1mg/L.The river water chemistry type in the Yarlung Zangbo River basin is type SO₄^2--Ca²⁺-Cl^--Mg²⁺,which has typical characteristics of rivers in the plateau of China.?2?The concentration of major cations in the Brahmaputra basin is ranked as Ca²⁺>K⁺>Mg²⁺>Na⁺by size,and the major anion concentration is HCO₃^->SO₄^2->Cl^-by size.The major ion concentrations in the Yarlung Zangbo River basin show some differences in water time on the time scale,with flat water period>dry season>wet season.?3?The hydrochemical characteristics of the Yarlung Zangbo River basin water body analyzed that the hydrochemical characteristics of the river basin water body are mainly affected by the weathering of the rock;human activities have a certain impact on the water body of the Yarlung Zangbo River,which is mainly affected by the mining industry activities on the water bodies.The impact is relatively small.?4?The hydrochemistry characteristics of the whole Yarlung Zangbo River basin was analyzed by traditional hydrogeochemical analysis methods such as Piper three-phasediagram,Gibbsdiagram,hydrochemicaltypeanalysis,ionospheric-temporal changes and water quality analysis.The results show that the Yarlung Zangbo The main ion composition of watershed is dominated by rock weathering.Some of the anions and cations in water bodies are affected by carbonate weathering and silicate,while the influence of evaporites can be neglected.According to the Piper three-phase diagram and the relationship analysis of(Ca²⁺+Mg²⁺)/HCO₃^-and SO₄^2-/HCO₃^-equivalent ratio,we can see that the sulfuric acid in the Brahmaputra basin waters generally participates in the rock weathering process.?5?The analysis of heavy metals in the water of the Yarlung Zangbo River,grasping the status of heavy metal pollution in the Brahmaputra basin,analyzing the spatial and temporal distribution of heavy metals Cu,Zn,Cr and As in the Brahmaputra basin,and clarifying the heavy metal pollution in the Brahmaputra.