It is now known that the policy of fluoridation of drinking water supplies is unsafe and places an unacceptable health burden and unsustainable environmental impact on the environment. Ireland is the only EU country with a legislative policy for the addition of fluoride compounds to public water supplies. In all other European countries alternative vehicles for fluoride exposure, such as toothpaste, are the accepted practice. According to the WHO1, where a population has a high level of dental awareness and uses toothpaste there is no need to supply fluoridated water.
Water fluoridation is the addition of a fluoride compound to drinking water supplies in order to increase its fluoride concentration. In Ireland public water supplies are fluoridated with fluorosilicic acid (also known as hydrofluorosilicic acid or hexafluorosilicic acid). The toxicology of hexafluorosilicic acid and hexafluorosilicictes compounds are incompletely investigated2. It is incorrect to assume that fluoride compounds used in water fluoridation dissociate entirely into fluoride ions, and harmless hydration compounds of silicon. In recent years, many studies have indicated that ingested fluoride induces free radical toxicity in humans and animals.3,4,5,6 From a toxicological perspective fluoride is regarded as more toxic than lead, and only slightly less toxic than arsenic.7 Pure fluoride solutions do behave relatively predictably, both over the permissible pH range of municipal water supplies and in the extremely acidic environment of the human stomach. In contrast, fluorosilicictes dissociate in highly complex fashion in water, with a range of complex derivatives forming at different pH values.8,9,10
1 Nutrients in Drinking Water, Water, Sanitation and Health Protection and the Human Environment World Health Organization, Geneva, 2005.
2 Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water, Scientific Committee on Health and Environmental Risks, Director General for Health & Consumers 2010
3 Kaushik T, Shyam R, Vats P, Suri S, Kumria MML, Sharma PC, et al. Glutathione metabolism in rats exposed to high-fluoride water and effect of spirulina treatment. Fluoride 2001;34:132-8.
4 Guan ZZ, Xiao KQ, Zeng XY, Long YG, Cheng YH, Jiang SF, et al. Changed cellular membrane lipid composition and lipid peroxidation of kidney in rats with chronic fluorosis. Arch Toxicol 2000;74:602-8.
5 Kalyanalakshmi P, Vijayabhaskar M, Naidu MD. Lipid peroxidation and antioxidant enzyme status of adult males with skeletal fluorosis in Andhra Pradesh, India. Fluoride 2007;40:42-5.
6 Shivarajashankara YM, Shivashankara AR, Bhat PG, Rao SH. Effect of fluoride intoxication on lipid peroxidation and antioxidant systems in rats. Fluoride 2001;34:108-13. 7 Williams and Williams (1984), Clinical Toxicology of Commercial Products, ppII-4, II- 112, II-129
8 Crosby NT; "Equilibria of Fluosilicate Solutions with Special Reference to The Fluoridation of Public Water Supplies"; J Appl Chem; v19; pp 100-102, 1969
9 Busey RH et al; "Fluorosilicicte Equilibria in Sodium Chloride Solutions from 0 to 60 o C"; Inorg. Chem V 19; pp 758-761, 1980.
When fluorosilicates are added to water they dissociate to form fluorosilicic ions [SiF6] 2- with two negative electrical charges, accompanied by either two individual ions of hydrogen H+ (from fluorosilicic acid) or of sodium (Na+) (from sodium fluorosilicates). The individual elements, silicon (Si) and fluorine (F) in the fluorosilicic ion cannot move independently - at neutral pH they act as the complex substance fluorosilicic. At around the normal pH of 7, approximately 97% of the fluorine in fluorosilicic added to the water is present in the form of ionised fluoride, F+.
At the very slightly acidic pH of 6, only 27% of the fluorine in fluorosilicates is present as fluoride - the rest is associated with other ions, and forms a number of complex and unstable compounds and ions that change over variable periods of time and at different pH values. At the acidity of the human stomach - pH2 to 3 - the proportion of fluorine atoms that are present as fluoride ions changes dramatically and effectively no fluorine atoms are present in the ionic state. Research11 undertaken by Dr. Johannes Westendorf, (Toxicology Department, Eppendorf-Hamburg University Hospital) found that under physiological conditions, dissociation of silicafluorides was no more than 66% in the concentration range considered optimum for fluoridated water.
Westendorf concluded, based on actual laboratory experimental evidence, that dilution of fluorosilicic acid to a nominal 1 part per million of free fluoride in water at pH 7.4 induces each [SiF6]2- to release 4 fluorides to be replaced by hydroxyls. The partially dissociated residue would be the ion [SiF2(OH)4]2- which would then be present in the water at the same concentration as the originally introduced SiF. The findings of Westendorf were supported in a scientific paper by Milton12 which observed that silicafluoricic acids contain, in addition to such primary silica, a secondary silica component with its own characteristic chemical behaviour. Because the composition of silica- saturated fluorosilicic acids approaches closely that of H2SiF6-SiF4 (fluorosilicic acid) for which S=1.2, the secondary silica will be considered to be present in this form.
10 Urbansky, E.T., and Schock, M.R.. Can fluoridation affect water lead levels and lead neurotoxicity? In: American Water Works Association Annual Conference
Proceedings, Denver, CO, June 11-15, 2000
11 Westendorf J. Die Kinetik der Acetylcholinesterasehemmung und die Beeinflussung der Permeabilitat von Erythrozxytenmembranen durch Fluroid und Fluorokomplex- Jonen. Doctoral Dissertation, Hamburg Universitat Hamburg Fachbereich Chemie, 1975.
12 Thomsen, Milton S, High-silica fluosilicic acids : specific reactions and the equilibrium with silica, Am, Chem, Soc. 74 : 1690-1692
The presence of dissociated silica fluorosilicic acid compounds was further acknowledged in a paper13 presented at the International Fertiliser Association technical committee meeting in 1999 which stated the following:
The dissociation of hexafluorosilicate has been investigated by Finney et al.14 to determine if fluorosilicate intermediates may be present in appreciable concentrations in drinking water. No intermediates were observable at 10(- 5)M concentrations under excess fluoride forcing conditions over the pH range of 3.5-5.
A single intermediate species, assigned as SiF5(-) or its hydrate, was detected below pH3.5. This research was limited as the full range of pH associated with gastric pH was not examined, however, it did importantly prove the existence of fluorosilicicte intermediates outside of H2SiF6.
The dissociation status of silicofluorides (SiF) depends on pH and its concentration in water so that incompletely dissociated SiF residues may re- associate both at intra-gastric pH around 2.0 15 and during food preparation, producing SiF species including silicon tetrafluoride, (SiF4), a known toxin.16,17,18,19,20,21
13 Smith Paul A. Société Chimique Prayon-Rupel SA, Belgium, HISTORY OF FLUORINE RECOVERY PROCESSES, Paper presented at the IFA Technical Sub-Committee and Committee Meeting, 15-17 September 1999, Novgorod, Russia
14 Finney WF, Wilson E, Callender A, Morris MD, Beck LW.
Re-examination of hexafluorosilicicte hydrolysis by 19F NMR and pH measurement. Environ Sci Technol. 2006 Apr 15;40(8):2572-7.
15 Ciavatta L, et al; ―Fluorosilicicte Equilibria in Acid Solution‖; Polyhedron Vol 7 (18);1773-79;1988
16 Gabovich RD; "Fluorine in Stomatology and Hygiene"; translated from the original Russian and published in Kazan (USSR); printed by the US Govt Printing Office on behalf of the Dept of Health Education and Welfare. US Public Health Service, National Institute of Dental Health; DHEW pub no (NIH) 78-785, 1977
17 Roholm K; "Fluorine Intoxication; A Clinical-Hygiene Study"; H. K. Lewis & Co. Ltd, London; 1937
18 Lewis RJ, jr.; "Hazardous Chemicals Desk Reference": Van Nostrand Reinhold; Fourth Edition.
19 Matheson Gas Products; 30 Seaview Drive, Secaucus, NJ; "Effects of Exposure to Toxic Gases" and MSDS for CAS # 7783-61-1; created 1/24/89.
20 Voltaix, Inc.; Material Safety Data Sheet for Silicon Tetrafluoride (SiF4).
21 Rumyantseva GI et al; "Experimental Investigation of The Toxic Properties of Silicon Tetrafluoride"; Gig Sanit ;(5):31-33, 1991.
” The chemical formula of fluorosilicic acid is H2SiF6. However, things are not as simple as that due to the fact that rarely is fluorosilicic acid present as pure H2SiF6. . . There are well reported references to the existence of H2SiF6 SiF4. . . Hereon in this presentation, FSA [fluorosilicic acid] means a mixture of HF, H2SiF6 and H2SiF6 SiF4”. Meaning there is more than one ionic compound.
Of interest also is the finding by Taves et al.22 who concluded that fluoride interacts with the silica, forming an aqueous fluorosilicicte in the vessel: "Plasticware (Falcon Plastics) was used for all analytical procedures to avoid contamination by fluoride from glass." It is further acknowledged that commercial SiFs are likely to be contaminated with fluosiloxanes, 23 arsenic and heavy metals, 24 and radionuclides,25 since they are waste products from fertilizer manufacture and uranium extraction from phosphate rock.26,27,28,29 Alarmingly, it is acknowledged that while the toxicological properties of silicafluorides or their derivatives have not been investigated30,31,32, they continue to be used as medical intervention additives in drinking water supplies. No short-term or sub-chronic exposure, chronic exposure, cytotoxicity, reproductive toxicity, teratology, carcinogenicity, or initiation/promotion studies are available. This is particularly alarming since fluorosilicicte compounds were used as pesticides in the USA till 1999.
In August 1995, the act was amended, eliminating fluorosilicate compounds from the registration list and their sale for pesticide use (40CFR153, Subpart H) (U.S. EPA, 1995). In the United States, all pesticide uses have been cancelled (U.S. EPA, 1999). Fluorosilicicte acid is listed in Section 8(b) of the USA Toxic Substances Control Act (TSCA; chemical inventory section).
There is concern regarding the health safety of SiFs on a number of counts:
possible formation of toxic complexes with aluminium, iron and other cations commonly present in treated drinking water; fluorosilicictes are particularly likely to react with aluminium compounds Al(OH)3 used in water treatment to produce several derivative compounds.
22 Guy WS, Taves DR, Brey WS, Organic Fluorocompounds in Human Plasma: Prevalence and Characterization, ACS symposium series, Washington, Symposium Series, No. 28 117 - 134.
23 Ricks GM et al; "The Possible Formation of Hydrogen Fluoride from the Reaction of Silicon Tetrafluoride with Humid Air": Am. Ind. Hyg. Assoc. J. (54); 272-276, 1993.
24 Craig JM; "Fluoride Removal from Wet-Process Phosphoric Acid Reactor Gases"; Ph. D. Dissertation; Univ. Fla. at Gainseville, 1970.
25 Murray RL; ―Understanding Radioactive Waste‖; Third Ed.(ed Powell JD); 1982 26 Becker Pierre; "Phosphates and Phosphoric Acid: Raw materials, technology, and economics of the wet process"; Marcel Dekker: New York (First ed.) 1983, Second ed., 1988.
27 Slack AV; "Phosphoric Acid"; Part I; Marcel Dekker: New York, 1968.
28 Greek BF, Allen OW, Tynan DE; "Uranium Recovery from Wet Process Phosphoric Acid"; Industrial & Engineering Chemistry; vol 49 (4); 628-636, 669-671, 1957.
29 Rahn FJ et al; ―A Guide to Nuclear Power Technology‖; John Wiley & Sons' New York; 1984
30 Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water; Scientific Committee on Health and Environmental Risks, Director General for Health & Consumers (2010).
31 U.S National Research Council. (2006). Fluoride in Drinking Water: A Scientific Review of EPA's Standards. National Academies Press, Washington D.C. 32 The Use of Data on Cholinesterase Inhibition for Risk Assessments of
Organophosphorous and Carbamate Pesticides, Office of Pesticide Programs US Environmental Protection Agency, August 18, 2000.
potential toxic effects from SiF dissociation residues in municipal drinking water that may be present.
the environmental impact of SiF on freshwater and marine ecosystems has not been properly investigated.
the biological and human health consequences of ingesting such a species have never been properly investigated.
The only extensive examination of the actual biochemical effects of SiF that has been encountered is the aforementioned German study33 which shows substantial changes in membrane permeability and enzymatic changes capable of substantially modifying neuronal excitability. Westendorf‘s results showed that fluoride in the form of the silicafluoride complex (SiF), as well as several other complexes, was a substantially more powerful inhibitor of cholinesterase than the simple fluoride ion released by sodium fluoride (NaF). The inhibition of cholinesterase by silicafluorides is not unusual as it has been widely scientifically documented that fluoride is capable of inhibiting a number of enzymes, including pre-glycolytic enzymes, phosphatases, and cholinesterase.34
These finding are of staggering significance as:
cholinesterase is one of many important enzymes needed for the proper functioning of the nervous systems of humans, other vertebrates, and insects.
glycolytic enzymes have been found to play a central role in dementia35 and
phosphatases metabolism plays a critical role in cellular function, physiology and disease, including allergy, asthma, obesity, myocardial hypertrophy, and Alzheimer's disease. 36,37
Cholinergic pathways innervate virtually every organ in the body, including the brain and peripheral nervous system. Acetylcholine plays an important role in the functioning of the nervous system. Acetylcholine (AChE) is a neurotransmitter which enables chemical communication to occur between a nerve cell and a target cell. This target cell may be another nerve cell, muscle fiber or gland.38 Inhibition of AChE leads to an accumulation of acetylcholine and a prolongation of the action of acetylcholine at the nerve-
33 Westendorf J. Die Kinetik der Acetylcholinesterasehemmung und die Beeinflussung der Permeabilitat von Erythrozxytenmembranen durch Fluroid und Fluorokomplex- Jonen. Doctoral Dissertation, Hamburg Universitat Hamburg Fachbereich Chemie, 1975.
34 United States National Library of Medicine, Hazardous substances databank 35 Iwangoff, P, Armbruster,R, Enz,A, Ruge W. M, Glycolytic enzymes from human autoptic brain cortex: Normal aged and demented cases. Mechanisms of Ageing and Development, Volume 14, Issues 1–2, September–October 1980, Pages 203–209 36 Hong Zheng, Shawn Alter, and Cheng-Kui Qu, SHP-2 tyrosine phosphatase in human diseases Int J Clin Exp Med. 2009; 2(1): 17–25.
37 Bottini N, Bottini E, Gloria-Bottini F, Mustelin T. Low-molecular-weight protein tyrosine phosphatase and human disease: in search of biochemical mechanisms. Arch Immunol Ther Exp (Warsz). 2002;50(2):95-104.
38 Dementi, B. ―Cholinesterase Literature Review and Comment‖; Pesticides, People and Nature; 1 (2); 59-126; 1999
nerve, nerve-muscle or nerve-gland interface. Peripherally, the accumulation of acetylcholine can result in cholinergic responses such as smooth muscle contractions (e.g., abdominal cramps), glandular secretions (e.g., sweating), skeletal muscle twitching, and, at higher concentrations, flaccid paralysis. In addition, there may be centrally mediated effects on learning, memory and other behavioral parameters. Thus, the inhibition of AChE potentially results in a broad range of adverse effects, having an impact on most bodily functions, and depending on the magnitude and half-life of an exposure dose, these effects can be serious, even fatal.
Little information exists describing effects following long(er)-term, low-level exposures to humans to anticholinesterase substances. Fluorinated organic compounds have widespread applications as pesticides, herbicides, pharmaceuticals, flame-retardants, refrigerants and foam-blowing agents, and are consequently accumulating in the environment.
Populations that are at increased risk from the effects of fluoride are infants who are bottle-fed formula milk reconstituted with fluoridated water and individuals that suffer from diabetes insipidus or some forms of renal impairment.
Apart from the possibility of direct toxicity the dissociated fluoride ions are known to bind to calcium and magnesium. If diets are low in calcium or magnesium the products of silicofluoride dissociation can exacerbate the competition between calcium and lead for bone and soft tissue sites. In addition, fluoride has a high affinity for proteins39 and is known to modify
39 Emsley, J., Jones, D.J., Miller, J.M, Overill, R.E., and Waddilove, RA. An unexpectedly strong hydrogen bond: Ab initio calculations and spectroscopic studies of amide- fluoride systems. I. Am. Chem. Soc. 1981: 203;24-28