Flourine contamination from industrial sources may be a significant issue if this paper from the 1950s still holds. It contains a powerful image of a leg bone of a cow with fluorosis, which resembles a knobbly tree branch in texture.
PS if you have got this far without falling asleep; very well done 
http://www.google.com/url?sa=t&rct=j...55123115,d.Yms
"
The problem of fluorosis in farm animals in Britain
is not due to the high fluorine content of rock phosphate
deposits, volcanic soils, or water supplies, but
arises from the emission of fluorine containing gases
and dusts from industrial plants. If the density of our
industrial areas is considered in relation to the relatively
small area of the whole country, it can be readily
understood that a great deal of agricultural land must
be adjacent to industrial works.
The chief sources of fluorine contamination of
grassland and crops are: (1) steel and metal works
when the method of production involves the use of
large amounts of fluorspar as a flux ; (2) brickworks,
where the source is usually the local clay, although coal
is sometimes a contributory factor; (3) production of
aluminium by the electrolytic reduction of alumina;
(4) glass, enamel, and colour works where fluorine
compounds are often added to facilitate melting and to
give the finished products certain properties ; (5) the
calcining of iron-stone where the sourtie is mainly the
fluorine-rich ore itself; (6) potteries and other ceramic
industries where the materials used in manufacture are
high in fluorine; (7)
collieries, power stations and
other industries which consume large quantities of
pulverised low-grade coal with a high fluorine content.
It is generally accepted that the fluorine content
of most plants, with the exception of the roots, is
not readily affected by the amount of fluorine in the
soil. There seem to be a few exceptions to this, notably
the tea plant. and the camellia, which appear to
be fluorine collectors, but common fluorine values for uncontaminated animal foodstuffs lie between 1 and
10 p.p.m. on a dry matter basis.
Excessively high
values’ up to 2000 p.p.m. have been reported (Green
1946) on herbage near sources of emission of fluorine
compounds. "
and a paper called The Emerging Medical and Geological Association from The American Clinical and Climatological Association http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1473139/ states
"
The health problems caused by fluorine volatilized during domestic coal use are far more extensive than those caused by arsenic. More than 10 million people in Guizhou Province and surrounding areas suffer from various forms of fluorosis. Typical symptoms of fluorosis include mottling of tooth enamel (dental fluorosis) and various forms of skeletal fluorosis including osteosclerosis, limited movement of the joints, and outward manifestations such as knock-knees, bow legs, and spinal curvature.
Fluorosis combined with nutritional deficiencies in children can result in severe bone deformation.
The etiology of fluorosis is similar to that of arseniasis in that the disease is derived from foods dried over coal-burning stoves. Adsorption of fluorine by corn dried over unvented ovens burning high ([greater than, closed by curve, equal, slanted]200 ppm) fluorine coal is the probable cause of the extensive dental and skeletal fluorosis in southwest China. The problem is compounded by the use of clay as a binder for making briquettes. The clay used is a high-fluorine (mean value of 903 ppm) residue formed by intense leaching of a limestone substrate."
In the west we do not have the same level of exposure but it is clear that coal could be a significant source of flourine emissions
Hybrid Mode
