Investigation and analysis on the distribution of high arsenic and high fluoride in Wusu City

Objective To deepen the depth and widen the range of the surveillance on the distribution of high arsenic and high fluoride in Wusu City thus to provide scientific basis for prevention. Methods In confirmed and suspected area of high arsenic and high fluoride, screening survey was carried out, and the levels of arsenic and fluoride in the water were determined. Results Amongth 1 069 water samples collected from manual wells and mechanized wells, 58.56% exceeded the criteria for arsenic and 41.12% for flouride. There were significant differences of the rates of water arsenic and fluoride going beyond the criteria among different villages and towns(χ2 = 739.58,384.72,P 0.001) and among the water samples from different depth of wells(χ2 = 790.89,384.72,P 0.001). Conclusions The over-criterion water arsenic and water fluoride prevails seriously;there are differences of levels of the water arsenic and fluoride in different villages and towns as well as in the different wells in the same village and town; high arsenic and high fluoride distribute in spots or patches.