Distribution Characteristics And Influencing Factors Of Dissolved 238U And [²³⁴U/²³⁸U]AR In Saline Lake Waters In The Northeast Of Qaidam Basin

Lake is an important part of the hydrosphere.We could obtain more key information about the geochemical behavior of lakes,the mixing characteristics of lakes,and the physical and chemical processes occurring in lakes by carrying out U-nuclide studies of lake water bodies.This is important for understanding the sources of important trace elements in water bodies.And the process of migration and transformation,and then revealing its potential environmental impact is of great significance.In this study,eight lakes with different salinities and Bayin River in the northeastern of Qaidam Basin were selected to explore the distribution characteristics and influencing factors of the dissolved ²³⁸U and the[²³⁴U/²³⁸U]AR?Activity Ratios?.These research results could provide basic data for the subsequent calculation of lake water uranium tracing,particulate matter retention time and lake water mixing time,which have important scientific significance for the exploration of past regional environmental changes in the future.The results show that:?1?The concentration of the dissolved ²³⁸U and the[²³⁴U/²³⁸U]AR of these lake waters in the study area show that there is no significant change in the same lake,during the same period,but there is a certain degree of difference in the distribution between different lake.The distribution of the concentration of the dissolved ²³⁸U in these lake waters mainly responds to the change of p H?Increasing with the increase of p H?.At the same time,that has a positive correlation with the TDS in a certain range.In addition,external supply water has a greater influence on the distribution of that in open lake water.?2?The[²³⁴U/²³⁸U]AR of these lake waters in the study area obviously deviates from the equilibrium value.After analyzing the consistent distribution characteristics of the[²³⁴U/²³⁸U]AR of these lake waters in the study area the differential distribution characteristics of the[²³⁴U/²³⁸U]AR of the Bayin River,we preliminarily believe that the distribution of the[²³⁴U/²³⁸U]AR of lake waters in the study area may be affected by external recharge water and/or water-rock interaction?atmospheric dust,debris particles brought by recharge rivers,lake sediments,etc.?during lake evolution impact.?3?The distribution of the concentration of the dissolved ²³⁸U of these lake waters fluctuate with seasonal changes in the study area,but the[²³⁴U/²³⁸U]AR of these lake waters remain basically stable.The analysis believes that this may be closely related to the seasonal changes of the lake's external supply water?precipitation,surface runoff,groundwater?.These results of the distribution characteristics of the[²³⁴U/²³⁸U]AR of these lake waters could provide basic data for the feasibility of establishing a U-Th chronological framework of sedimentary sequences through lake-derived biogenic carbonate.At the same time,it lays a certain foundation for in-depth interpretation of the recorded environmental change information based on the accurate establishment of sediment and/or biogenic carbonate U-Th era.The results of the relationship between the distribution of the concentration of dissolved ²³⁸U and TDS and/or p H in these lake waters could provide basic data for the reasonable development of local uranium resources and the harmless treatment of low-concentration uranium-containing wastewater in the future,which has certain practical significance.