Study On The Transfer Rule Of Hg, As, Se For Weihe River In Xi’an

As the largest tributary in the Yellow River basin, Weihe River is located in the Xi’an City and merged into Yellow River in Tongguan. The water quality of the Weihe River has important significance for the development of the Xi’an City and the protection of water resource in the Weihe River basin. The surface water samples were taken monthly from January 2013 to December 2015 at 9 sites distributed following the stream flow direction of the river. The pollution and transfer rule of metals(Hg, As, Se) in Weihe River was studied.A hydride generation atomic fluorescence spectrometric detection method has been developed for the determination of mercury, arsenic and selenium in water samples. The effect of instrument operating conditions, the choice of pretreatment agent, the concentration of hydrochloric acid and KBH4-KOH were investigated and optimized. The experimental results show that the atomic fluorescence intensity was linear with mercury concentration in the range of 0-5μg/L, arsenic concentration in the range of 0-30μg/L, and selenium concentration in the range of 0-25μg/L. The proposed method has been applied successfully to the analysis of mercury, arsenic and selenium in Weihe River.Through the experimental to get three years of water quality monitoring results of metals of Weihe River, the concentrations of the studied metals were found to be below the National Standard of Environmental Quality GB3838-2002, and acceptable concentration for drinking water except some value for Se. No obvious As pollution resources exist in the studied area, whereas potential Hg and Se pollution resources do. Different metals have different contents in different period of river. The order of mercury content in the water in different period is: mean flow season>flood season>dry season; the order of arsenic is: flood season>dry season> mean flow season; the order of arsenic is: flood season> mean flow season>dry season.The concentration of metal Hg and Se has no clear correlation with GDP and industrial wastewater discharge, while the concentration of metal As is well correlated with GDP, it’s show clear that Xi’an’s rapid development of economy have certain influence in the concentration of As. In the monitoring point of Fenghe River, the concentration of dissolved Hg is well correlated with the concentration of dissolved Se(p<0.05), it is speculate that Hg and Se may come from the same pollution source in Fenghe River.