Fertilizer from phosphate rock is processed with silicon tetrafluoride gas. The gas gathers impurities and becomes hydrofluosilicic acid when it passes through water scrubbers. The Cominco phosphate mine in Trail, B.C. is a major supplier of hydrofluosilicic acid for western Canada and the Pacific Northwest. The table below lists the results of a chemical analysis by Cominco of a solution of hydroflusilicic acid from the Cominco phosphate plant. These data were published in “Some Just Don’t Like Drinking Arsenic: Calgary’s Water Fluoridation Fight Isn’t Over Yet,” Alberta Report, February 17, 1992, vol. 19, no. 9, pp. 18f.
|Cadmium||less than 0.05 mg/L|
mg/L is equivalent to parts per million in water.