Study On The Migrating Charateristics Of Nitrogen At Sediment-water Interface In Xinjiang Dongdaohaizi

In recent years China's are accompanied by increased generation of domestic and industrial wastewater.Large quantities of wastewater has been discharged into urban lakes,resulting in serious pollution problems such as oversupply and high concentrations of nutrients,deterioration in water quality,and rapid ecological degradation.This study analyzed study on the migrating and transforming charateristics of nitrogen at sediment-water interface in Xinjiang Dongdaohaizi,which is located at the estuary of the Urumqi River in Xinjiang.The findings of the study can provide a theoretical basis for protecting and managing this lake in a scientific way.?1?A correlation analysis between physical and chemical indicators of the lake's environmental conditions and the nitrogen concentrations of the sediment and overlying water suggests that there were positive correlations between the concentrations of different forms of nitrogen,and the concentration of each nitrogen form was negatively correlated with water temperature.The temporal variation in the total nitrogen TN and NH₄⁺-N content of the overlying water followed the same pattern:dry season>normal season>wet season.The nitrate nitrogen NO₃^--N content of the overlying water reached the highest levels in the dry season,but it was higher in the wet season than in the normal season.In the interstitial water,both the TN and NO₃^--N concentrations were higher in the dry season than in the wet season and reached the lowest levels in the normal season;NH₄⁺-N was most concentrated in the normal season,less in the dry season,and least concentrated in the wet season.In the surface sediment,the NH₄⁺-N and NO₃^--N concentrations had the same distribution across the three seasons:normal season>dry season>wet season;the TN levels were higher in the dry season than in the normal season,and the lowest levels also occurred in the wet season.?2?The kinetic curve describing the NH₄⁺-N abso NH₄⁺-N was rapidly adsorbed by the surface sediment.After 2 hours of vibration.This suggests that the sediment reacted intensely with the NH₄⁺-N solution immediately after they were put together.Commonly used adsorption kinetic models were then fitted to the experimental data.It was found that the significance levels of the correlations between the experimental data and the modeled data from the pseudo-second-order models were higher than 0.99.This suggests that these models can describe the kinetic characteristics of NH₄⁺-N adsorption on the sediment in Lake Dongdaohaizi more accurately than the other two types of models.Among the thermodynamic models,the Henry model fitted the NH₄⁺-N adsorption data for different concentrations well,with the significance levels ranging from 0.903 to 0.995.?3?The experimental simulation of nitrogen exchange flux was performed in Lake Dongdaohaizi.The results show that nitrogen exchange flux across the Sediment-water interface reached the highest levels in the wet season,and the lowest levels in the dry seasons.Whether the nitrogen exchange could occur depends on the concentration difference between the overlying water and interstitial water.The direction,rate,and level of nitrogen exchange across the Sediment-water interface in this lake were affected by various factors,such as water temperature,redox potential,dissolved oxygen,glacial meltwater,and rainfall.Temperature and degree of bioturbation were the major factors influencing the exchange flux.