Fluoride: Diffusive mobility in soil and some remedial measures to controlits plant uptake

Dietary (human) intake of fluoride (F) largely through consumption of agric ultural produce grown in F contaminated environment, has recently been view ed as an important cause for several F related health problems in many part s of the world. Being a non-essential element, F is usually taken up by pla nts through passive uptake - a process which is dominantly diffusion contro lled. Still very little is known regarding F diffusion in soil, Tn present study, diffusion of F in the alluvial soil (Entisol) of Dayalbagh (Agra) ha s been investigated as a function of soil water content (theta) and F conce ntration gradient. The data on F diffusion coefficients were recorded bg de termining the F concentration profile in horizontally incubated and homogen ized soil columns, under varied experimental conditions (theta = 0.12-0.25 cm cm(-3), pH = 7.3 +/- 0.2, incubation time (t) = 96-384 h, temperature = 303 +/- 1.2 K, The effects of aluminium and calcium, which are known to be strong binders for F in soil, on the F diffusion have also been investigate d. The study, particularly, throws light on the possible dual role of alumi nium in affecting the diffusion of F in soil which might prove critical in the ultimate uptake of F by plants in specific environmental conditions.