The mobility of soluble fluoride in soils

The factors which promote retention or release of soluble fluoride species by soils have been reviewed with the aim of identifying key processes. The topics considered include fluoride levels in soils, mobility as demonstrated in leaching studies, and fluoride adsorption by soils. The role of competing chemical equilibria has been considered, through discussion of chemical interactions involving fluoride species and soil components such as clays, hydrous oxides (Al, Fe, Mn), organic matter, calcite and quartz.

The mobility of fluoride tends to be a function of soil type, system pH and F levels, with retention being favoured in acidic sediments containing clays and poorly ordered hydrous oxides of aluminium.