| Fluoride (F) is one of necessary micronutrients for both humans and animals. The optimum F level in drinking water for health is between 0.5 and 1.0 mg/L, and maximum concentration allowed is 1.5mg/L. Excessive intake of F may cause fluorosis. Interaction of F with Al in acidic soils may cause significant variations in physicochemical properties of soil solution and surface characters of soil particles due to high affinity of fluoride for Al, which may significantly influence bioavailability of plant nutrients and leaching of potentially toxic metallic elements. It is of great significance to investigate the interactions of F with soils and its effects on mobilization of Al and sorption of phosphate (P) in soil.In this dissertation, red soil, a typical acidic soil, is collected from Jiangxi Province and used for the study. The main contents of our experiments include: (1) the alterations in solution pH, total soluble F, free F, bound F and adsorbed F in the process of interaction between F and red soil; (2) the effects of F on Al mobilization and the variations in the size of active solid-phase aluminum pools in red soil; (3) the competitive adsorption and desorption of F with P, and (4) the effect of Fe/Al oxides on F and P adsorptions after removing of Fe/Al via DCB method. Some main conclusions are drawn as follow:1. Due to high affinity of F for Al, bound F in solution and adsorbed-F increase rapidly within short time, accordingly the total soluble F and free F decrease to different extent. A decrease in pH of fluoride solution leads to an increase in adsorbed and bound F, and correspondingly a decrease in free and total F.2. Fluoride can accelerate leaching of Al from soil minerals and equilibrium of the process can be reached in 10 to 30 min. Soluble Al and various forms of active slide-phase aluminum pools increase greatly in the present of F, which suggests that interaction of F with red soils probably remove some non-crystalline coatings,...
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