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Hydrogen Fluoride Calculations

A 23% fluosilicic acid solution, because of the chemistry of aqueous fluorides, typically contains around 1.5 % HF (as assayed by Lucier Chemicals for Metropolitan Water, Los Angeles).

This is 23 grams of H2SiF6 and 1.5 grams of HF per 100 grams of solution, which is 18 grams of fluoride from H2SiF6 and  1.5 grams of fluoride from HF.

Thus, 8% of all fluoride present in the solution is HF.

The Code of Federal Regulations specifically and explicitly prohibits the marketing, interstate transport, or ingestion of any anti-caries agent that contains HF without a new drug application – NDA.

Fluosilicic acid hazardous waste preparations are currently diluted into nearly 70% of all U.S. water supplies without FDA approval and without a prescription. A 1.0 ppm fluoridation level produces 0.21 ppm anionic fluorine in human blood, and such action requires an FDA ban, or an approved NDA.

Here also is the calculated HF concentration that would be present in the stomach if one were thirsty and filled up from drinking 1 ppm fluoride water. That is:

HF  produces H+ and F as a weak acid with dissociation constant Ka = 7.2 x 10-4 (CRC Handbook for Chemistry and Physics)

So 7.2 x 10-4 = [H+][F]/[HF] where [F], after combining with stomach acid H+, = 5.2 x 10-5M – X (1 ppm in molarity units minus the unknown molarity X for HF)

Rearranging, 7.2 x 10-4X = [10-3][5.2 x 10-5 – X]  and 0.00172X = 5.26 x 10-8

Solving,  X = 3 x 10-5 M HF in stomach acid, which is 0.6 ppm HF.

This agrees with experimental observations with a fluoride ion specific electrode at pH 3, where 1 ppm fluoride water is detected as only approximately 0.5 ppm. This level of HF is a significant concentration of this uncharged tissue-penetrating corrosive in contact with stomach mucosal tissue.

I will be calling this to the attention of the FDA.

I calculated the concentration of HF that would be present in a solution that is buffered to pH 7 with 1 ppm total fluoride and it is about 0.14 ppb of this corrosive substance HF. This would be unimpressive to those promoting fluoride to be concerned about, but nevertheless it is the most corrosive substance known and is the active ingredient in industrial uses on glass, ceramics, computer chips, etc. when conditions are not buffered. In plain water without buffering, the HF is higher.

Richard Sauerheber, Ph.D.
(B.A. Biology, Ph.D. Chemistry, University of California, San Diego)
Palomar College, San Marcos, CA  Phone: 760-744-1150 xt 2448