FLUORIDE
        Exposure to fluorides happens mostly from eating contaminated foods, breathing workplace air, or eating toothpaste. Exposures are usually low and not harmful. High exposures can cause lung, skin, and bone damage.

        Toothpaste and mouth rinses have fluorides added to prevent cavities. If drinking water supplies are low in fluoride, many communities add fluorides to help prevent cavities. Some skin medicines and cancer treatment drugs also contain fluorides.

        How Might I Be Exposed to Fluorides?
- Breathing workplace air where fluorides are used or released
- Eating food from soil with high natural levels or high levels from fertilizers or nearby waste sites
- Eating toothpaste that contains fluorides
- Drinking contaminated water
- Ingesting contaminated soil particles.

        How Can Fluorides Affect My Health? Fluorides are everywhere throughout the environment, but at very low levels that are not believed to be harmful. Small amounts of sodium fluoride help reduce tooth cavities, but high levels can harm your health. In children whose teeth are forming, high fluoride exposure can cause dental fluorosis with visible changes in the teeth. In adults, high fluoride over a long time can lead to skeletal fluorosis with denser bones, joint pain, and a limited joint movement. This is extremely rare in the U.S.

        While not carcinogenic, the effects of fluoride on reproduction of developing fetuses is unknown. Cows and various birds are known to have reproductive problems when they eat or drink large amounts of fluoride. The results from laboratory studies in animal are mixed.

        What levels Protect Human Health? The Environmental Protection Agency (EPA) sets a maximum amount of 4 milligrams fluoride per liter of drinking water (4 mg/L). EPA recommends that states limit fluoride in drinking water to 2 mg/L.




Source: http://www.ci.sf.ca.us/puc/wqfs/tocsec4.htm