Fluorine content in soils of the Linfen-Yuncheng basin, southern Shanxi, China, and its influence factors

Studies of the spatial changes and influence factors of contents of fluorine and related elements in top soils(at 0-20 cm depth) of the Linfen-Yuncheng basin show that the average fluorine content in soils in the basin is 520 mg/kg,being far higher than that of the background values of China.The F content in top soils is of uneven distribution and has a trend of increase from the peripheries of the basin toward the center.Some statistical methods such as correlation analysis,regression analysis and factor analysis were applied for the study.Study indicates that the distribution of F content in soils is mainly controlled by factors such as the physico-chemical properties of silts and organic matter,interaction between elements and F adsorption,and in addition,the human factor has also certain influence.The physico-chemical properties of silts and organic matter have significant influence on the F content in soils,indicating that the F content in soils is related to the special chemical properties of F and parent rock types.Factor analysis finds that:the F distribution in top soils in the study area is probably influenced by the natural geological processes and anthropogenic processes and N,Cd,Se,Cu,Zn and Mo may represent the original associated elements of F;the F content in soils increases with an increase in Mo,Zn,Fe and Mg contents,which might be related to adsorption of Fe3+ ions in soils;whereas the coordination and substitution of F-and OH-might be the dominant factor for adsorption of F-in soils.