Fluoride livestock

Air pollutants that present a hazard to livestock, therefore, are those that are taken up by vegetation or deposited on the plants. Only a few pollutants have been observed to cause harm to animals. These include arsenic, fluorides, lead, mercury, and molybdenum. 

The movement of fluoride through the atmosphere and into a food chain illustrates an air-water interaction at the local scale (<100 km) (3). Industrial sources of fluoride include phosphate fertilizer, aluminum, and glass manufacturing plants. Domestic livestock in the vicinity of substantial fluoride sources are exposed to fluoride by ingestion of forage crops. Fluoride released into the air by industry is deposited and accumulated in vegetation. Its concentration is sufficient to cause damage to the teeth and bone structure of the animals that consume the crops. 

Fluorides do nol usually ntnve from the soil lo plants and on to livestock feedstuff s and human foodstuffs ill amounts that are toxic. Injury tu plants from fluoride in the soil has been noted on soils that are loo acid for the satisfactory growth of most plants. On limed soils or soils w ith sufficient calcium for optimum growth, any fluorine added lo the soil reacts with the calcium and other soil constituents to form insoluble compounds, which are not taken up by the plants. Rock phosphate and some kinds of superphosphate fertilizers contain large amounts of calcium fluoride, bul the fluorine content of the plants grown on soils that have been heavily fertilized with these phosphates is nut appreciably increased. Tea and some other members of the Theaeeae family are the only plants that take up very-much fluorine from the soil. 

Excessive amounts of fluoride in the soil can cause tooth and bone damage in livestock. Paris of Arkansas. California. South Carolina, and Texas have soils abnormally high in fluorine content. In serious situations, diarrhea and emaciation will he exhibited by the livestock. The effects depend upon the fluorine source and species of livestock. Exceptionally high fluoride levels can he encountered near smelters where pollution safeguards have not been installed or are ineffectively maintained. As cninpared with other livestock, pigs can tolerate much more fluorine (up lo nearly 300 ppm of fluorine derived front rock phosphates). 

The toxic nature of fluoride ion, F, is not confined to its presence in HF. It is toxic in soluble fluoride salts, such as NaF. At relatively low levels, such as about 1 ppm, used in some drinking water supplies, fluoride prevents tooth decay. At excessive levels, fluoride causes fluorosis, a condition characterized by bone abnormalities and mottled, soft teeth. Livestock are especially susceptible to poisoning from fluoride fallout on grazing land as a result of industrial pollution. In severe cases, the animals become lame and even die. 

Sodium fluosilicate (sodium silico fluoride) has been used to control ectoparasites on livestock, as well as crawling insects in homes and work buildings. It is approximately as toxic as sodium fluoride. 

Fluoride emissions cause damage to vegetation and harm to livestock that consume vegetation. 

Fluorosis is also sometimes associated with the use of mineral phosphates as dietary supplements for livestock, since these products may contain undesirably high levels of fluoride. The level present in mineral phosphate is a consequence of the geochemical conditions which obtained during deposition, and North African and North American mineral phosphate usually has about twice the content of fluoride (3-4 per cent) which is present in deposits in islands in the Pacific and Indian Oceans [106],... 

Most plant species appear to have a limited capacity to absorb fluorine, even from contaminated soils [237] and the fluorine content of uncontaminated plant material is normally low enough to make the development of fluorosis in livestock unlikely. A number of Australian grasses analysed by Harvey [238], some of which had been grown in areas irrigated by water substantially contaminated with fluoride, were found to contain fluorine levels restricted to the range 1 to... 

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