The Research On Biological Validity And The Characteristics Of Species Of Soil-Fluorine In Chengdu

Fluorine is both harmful element and necessary element tohuman and some otheranimals. In environment, whenever fluorine is excessive or lack, it can affect thehealth of human, bring epidemic fluorosis. The distribution of total fluorine and otherspecies of fluorine in Chengdu soil and their biological validity are studied in thethesis.The major research result is as follows:1. The research result of mensuration method of fluorine content in soilThe three determination methods of fluorine were compared .Among standardcurve method, TISAB standard additions method and perchloric acid standardadditions method. TISAB standard additions method gives the highest averagerecovery of 97.1ï¼…(ranging 87.1％～102.5ï¼…).2. The research of optimization condition of leaching water-soluble fluorine in soilsamplesFour optimization conditions have been maked: size of soil granule: 60 mech, theratio of water to soil: 10:1, distilled temperature: 60℃, leaching time: 30 min.3. Distribution of total soil-fluorine and analysis of other species of fluorine in soilsamplesThe distributions of soil-fluorine in Chengdu have been investigated: Res-F>>O.M.-F＞Ex-F＞Ws-F＞Fe/Mn-F, and that, average content of soil fluorine is507.061 mg/kg. Compared with soil standard contained fluorine, that is higher thanthe last line of 2nd level soils fairly(The fluorine content in the 2nd level soils is: 300—500 mg/kg). And the distribution is symmetrical, in which, fluorine content inwest suburb is highest. Both the physical and chemical properties of the soil samplesfrom the suburb of Chengdu have been tested and all of the soil samples are mainlyacid soil.Through establishing step regression equation between physical and chemicalproperties of the soil samples and all species of fluorines, the factores that influencespecies of fluorine content have been found and the most major influencing factor is:PH, CaCO₃ content, CEC and Alcontent.4. The biological validity analysis of fluorine in Chengdu soil We analysed fluorine content of root, stem and leaf of spinach, celery, cabbageand radish samples from Chengdu suburb, and respectively studied the influence ofthe physical and chemical properties of soil samples and all of species fluorine in soilon the fluorine content in plant body.