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In this paper we report on a preliminary investigation into the accumulation of fluoride by a number of marine and intertidal animals. The work was prompted by the recent building of an aluminium smelter at Lynemouth in Northumberland which discharges a fluoride-loaded effluent into the sea. However, dilution by seawater renders contamination negligible and it is suggested that tissue fluoride concentrations represent background levels for the animals studied.

In both vertebrates and invertebrates, fluoride is largely accumulated in skeletal structures. There is little or no accumulation in soft, edible tissues, with the exception of fish skin.

Preliminary toxicity tests were carried out on a number of marine invertebrates. Even at unnaturally high ambient fluoride levels, no adverse effects were seen, except possibly in the case of the filter-feeding mollusc Mytilus edulis.

Vegetation samples were collected in June and Oct. 1970 at varying distances from the Anaconda Aluminium Co. plant at Columbia Falls, Montana. Determinations were of foliar F concn., injury index II (an estimate of gross amount of visible injury or ‘burn’ for foliage of a given year), insect pest populations, and F concn. in insects collected within 0.5 mile of the Al reduction plant. Vegetation in control areas contained <10 p.p.m. F. II was shown to be a conservative parameter of pollution since many samples with high F concn. did not show injury. F concn. in vegetation samples was used as the basis of pollution mapping, whereby the pollution index in ‘isopols’ is equal to the local F conc. (with 10 as the background value). Visible injury occurred above 30 isopols (on a total area of 69 000 acres) in susceptible species, viz. pines (Pinus albicaulis, P. contorta, P. monticola and P. ponderosa) and Douglas fir (Pseudotsuga menziesii); the herb Smilacina stellata was a particularly sensitive indicator of F pollution. Nearly all vegetation was injured moderately at 100-300 isopols and (except grasses) severely at 300-600 isopols. Characteristics symptoms of F injury in conifers included enlarged cell nuclei and hypertrophy of resin-canal epithelium and vascular parenchyma.

The standards published herein have been promulgated as Public Health Regulations in the Federal Register.  As such they became effective April 5, 1992, as the Standards to which drinking water and water supply systems used by carriers and others subject to Federal quarantine regulations must conform.

We do know the use of drinking water containing as little as 1.2 to 3.0 parts per million of fluorine will cause such developmental disturbances in bones as osteosclerosis, spondylosis, and osteopetrosis, as well as goiter, and we cannot afford to run the risk of producing such serious systemic disturbances in applying what is at present a doubtful procedure intended to prevent development of dental disfigurements among children.  […]  Because of our anxiety to find some therapeutic procedure that will promote mass prevention of caries, the seeming potentialities of fluorine appear speculatively attractive, but, in the light of our present knowledge or lack of knowledge of the chemistry of the subject, the potentialities for harm far outweigh those for good.

Distribution of the element fluorine is so widespread throughout nature that a small intake of the element is practically unavoidable. Fluorides are general proto-plasmatic poisons, probably because of their capacity to modify the metabolism of cells by changing the permeability of the cell membrane and by inhibiting certain enzyme systems.