Zhao Shengnan

Atmospheric deposition characteristics and fluxes of heavy metals in Lake Ulansuhai

This paper studied heavy metal pollution of the Lake Ulansuhai caused by atmospheric deposition. Atmospheric deposition samples using a wetting method were collected in 1-30 July,2013 around the lake. The monthly deposition flux and the heavy metal elements of Cu,Zn,Pb,Cd,Cr,Hg and As deposition to the lake were measured. The element deposition flux ranked in Zn Pb Cu Cr As Hg Cd. The Lake Ulansuhai social investigation and data analysis showed that a larger deposition flux was distributed under the main wind direction as the heavy metals absorbed on the atmospheric particles moved and deposited relying on the wind. Wind is one of the factors affecting the Take Ulansuhai atmospheric heavy metals deposition flux. Besides the large heavy metal amount entering into the lake in the way of draining,the atmospheric deposition was another important pollution sources. The monthly atmospheric deposition amount of Zn,Pb,Cu,Cr,As,Hg and Cd into the lake were 10. 6,1. 04,1. 02,0. 833,0. 342,0. 00514 and 0. 00281 t / month. The heavy metal pollution contribution by the atmospheric deposition was estimated by the increment of heavy metals in the sediments. The atmospheric deposition contribution of Hg,Zn,Pb,Cu,As,Cd and Cr are estimated with 46. 4%,44. 7%,14. 1%,12. 0%,8. 48%,4. 75% and 4. 03%,respectively.

The humus composition and distribution of Lake Wuliangsuhai sediment

The paper studied the organic matter contents,humus composition and the degree of humification of the surface sediment of Lake Wuliangsuhai by chemical method.Correlation between sediment humus and physical-chemical factors were also discussed.The results showed that the organic matter of the surface sediment varied from 1.06% to 5.38%.Their distribution characteristics were related to hydraulic condition,aquatic plant distribution and human activities.In the humus composition,the content of humic acid and fulvic acid varied from 0.65 to 2.78 g/kg and from 2.19 to 8.72 g/kg,respectively.The humin is the main component in the sediment,ranging from 3.28 to 20.92 g/kg.Based on the correlation analysis of humus and environmental factors,each component is significantly correlated with the organic matter content.The pH value is significantly negative correlated with humin.Dissolved oxygen is significantly positive correlated with fulvic acids and significantly positive correlated with humin.The organic matter content increased while the content of extracted humic substances is decreased in the humification analysis.The PQ values range from 9.50% to 27.06%,with the average of 21.47%,which varied dramatically and with low degree of humification.

Water quality variation in Lake Wuliangsuhai, 2005-2014

To identify the water quality variation in the Lake Wulansuhai, the observation data on the water quality during June and September from 2005 to 2014, is analyzed using a Grey Model, based on factors including dissolved oxygen,chemical oxygen de⁃ mand, total nitrogen, total phosphorus, and fluoride. The driving force analysis on the water quality variation is carried out in terms of exogenous pollution, pollutant loading and the quantity of water input to the lake. The results show that during the period of 2005 to 2014, the water quality of the Lake Wuliangsuhai was getting better. The concentration of each pollution index, except total phosphorus, was decreased with different degrees. The grey comprehensive index shows that the water quality of the Lake Wuliang⁃ suhai was improved and the governance of total phosphorus should be the main manner of pollution controls. The key driving factors of the water quality of the Lake Wuliangsuhai getting better are due to the increasing the quantity of water input to the lake and the reduction quantity of input pollutant quantity as well as the reduction of exogenous pollution.

Impact of seasonal ice structure characteristics on ice cover impurity distributions in Lake Ulansuhai

Investigation and analysis of ice core on Lake Ulansuhai from ice season of 2013 to 2014, observational parameter in⁃ cluded ice thickness, examination of ice crystal type and bubble structure contributing to the ice cover, measurements of total nitro⁃ gen(TN), total phosphorus(TP) and chemical oxygen demand(CODCr) . The preliminary analyses were as follows: the ice cores were divided into four layers. The two middle layers were the mainly thermal ice growth areas. The ice cover was consisted of colum⁃ nar⁃crystal ice for the most part, and the crystal size increased with the ice⁃cover depth and the gas content decreased with the in⁃ crease of density. The content of contaminates (TN, TP, CODCr)were significantly correlated with density and gas content ( rTN = 0.8965, rTP = 0.8718 and rCODCr = 0.8184), and we respectively established the multiple regression equation to reveal the lake wa⁃ ter quality characteristics in frozen period. It provides theory basis for seasonal ice⁃cover study and water resources planning and management in ice season.

Distribution characteristics of mercury and pollution risk assessment in the water of Lake Ulansuhai

To understand the heavy metal mercury levels in the surface water of Lake Ulansuhai,samples were collected in January 2011.The total mercury concentration was analyzed.Distribution characteristics,pollution levels and health risk assessment were revealed by GIS,Pollution Evaluation Index and Health Risk Assessment Model.The average mercury concentrations in surface lake water were 1.04 μg / L,indicating a relatively high content of mercury.All sampling contents were beyond the first surface water standards and national fisheries standards,and 50% samples were beyond the fourth surface water standards.The high mercury concentrations at the inlet of the lake,while the low concentrations at the outlet of the lake.Considering the health risk caused by non-carcinogen in the water,the risk levels ranged from 0.75 × 10- 9to 2.15 × 10- 9a- 1.The contribution rate of mercury is 71.43%-92.44%.The mercury pollution and risk is high and should pay more attention on that.