| Fluoride is a common contaminant in water supplies. At concentration above 1.5 mg/L, it can cause dental fluorosis. At concentration of 4 mg/L and above, it can cause skeletal fluorosis. Granite and volcanic rocks can contain high amounts of fluoride. Fluorite (CaF2) is the principal mineral of fluoride. Countries with excessive fluoride in drinking water include India, China, and Africa. Fluoride is common in groundwater sources with high bicarbonate and low calcium. The greater Middle East area has an arid to semiarid climate, where people consume high amounts of water. The fluoride concentrations in the area can be below 1 mg/L, such as in Jordan and Iraq, and higher than 10 mg/L, such as in Yemen and Pakistan. Foods and beverages can have significant fluoride concentrations, especially tea. Anthropogenic sources of fluoride include steel, phosphate, and aluminum manufacturing industries. Fluoride can be removed from different treatment process such as corncob adsorbents and reverse osmosis. An on-site removal process is necessary to treat excess fluoride in rural areas in the Greater Middle East. |
