Drinking water, iodine nature

The iodine content of drinking water varies considerably with geography but remains stable with time. The presence of iodine in natural waters indicates concurring humic substances derived from a marine source rock. 

Dietary iodine is found in food, iodi2ed salt, milk and drinking water in the form of iodide or iodate of potassium, calcium, or sodium (Venkatesh and Dunn, 1995). Certain diets are naturally iodine-rich, while others contain very little iodine. Furthermore, it is known that certain geographical regions are iodine-poor (e.g., mountainous areas), and lower economic status may afford less variable food products, resulting in limited access to iodine-containing or iodine-enriched foods. 

Natural cyanobacterial blooms are typically sampled at sites where the accumulation of the cyanobacteria is likely to affect both humans and livestock, or at drinking water reservoirs. Samples are taken for quantitative and structural analysis and also for microscopic identification. The samples for microscopic identification are normally collected in brown glass bottles and preserved in LugoTs iodine solution or formaldehyde solution. Samples for quantitative and stractural analysis are normally collected in large wide neck glass or plastic bottles [121]. 

Deficiency of T. e. can lead to characteristic deficiency symptoms or diseases, thus indicating the essential nature of these nutritional factors, e g. iodine is a component of the thyroid hormones and essential for thyroid function. Iodine deficiency is responsible for endemic goiter, and certain types of cretinism it can be avoided by addition of iodides to drinking water. Other T. e. are chromium, copper, fluoride, magnesium, manganese, nickel, vanadium, silicon, tin, selenium, zinc (see individual entries). 

Fluorine is at the top of the column (VII A) in the Periodic Table known as the halogens or salt formers. Chlorine, bromine, iodine, and astatine are also in the halogen group. Halogens easily accept electrons from other atoms and combine with metals to form salts. In nature, fluorine is found in ores of fluorspar (calcium fluoride) and cryolite (a combination of sodium, fluorine, and aluminum). In the body, fluorine is found in the blood, bones, and teeth. Many communities in the United States add small amounts of fluorine to drinking water, since the presence of fluorine has been found to prevent the formation of cavities in teeth. 

Caution Avoid drinking unpasteurized milk products and practice good veterinary vaccination practices to avoid natural forms of brucellosis. In a terrorism attack with aerosol, livestock could possibly become contaminated. If this occurs, animal products should be pasteurized, boiled, or thoroughly cooked prior to eating. Water would have to be treated by boiling or iodination after any intentional contamination with brucella aerosols. 

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