Occurrence Characteristics of Arsenic in Water and Sediment after Arsenic Pollution Control in Yangzonghai Lake,Yunnan

By collecting surface water,overlying water and surface sediments samples in Yangzonghai Lake,arsenic in water and arsenic speciation in sediments were determined. The spatial distribution characteristics and seasonal variation law of arsenic after arsenic pollution control were discussed. The results showed that the high arsenic area in surface water was distributed in the Midwest and North of Yangzonghai Lake,and the average concentration of surface water was 18. 46μg/L. In the overlying water,the high arsenic area was concentrated in the North and Southeast. The average concentration of total arsenic in overlying water was 25. 39μg/L. In spring,the total arsenic concentration in surface water was higher than that in overlying water. There was no significant difference in total arsenic concentration of surface water and overlying water among the other three seasons. The average arsenic concentration of water was 35μg/L. The total arsenic concentration in water body was the lowest in spring,and the total arsenic content in sediment was the highest in spring. The average concentration of surface sediment was 24. 13 mg/kg. The arsenic in sediment was mainly residue-bound. Ionic arsenic,carbonate-bound arsenic and iron-manganese-bound arsenic were low in content. In conclusion,after controlling the pollution,the concentration of arsenic in lake water and sediment decreased gradually. The ecological risk of arsenic reduced further.