This is Ken Perrott’s response to Paul Connett’s last article Fluoride debate: Arguments against fluoridation thread. Part 5. Paul.
For Paul Connett’s original article see – Fluoride debate Part 1: Connett.
Paul’s last article was another Gish gallop of arguments and questions he demands I answer. I discussed the use of the Gish gallop as a tactic for avoidance in my last article. In this article Paul demonstrates how the Gish gallop enables the user to also claim their discussion partner is “ducking” issues and “didn’t address,” “didn’t acknowledge,” “didn’t comment on” or “didn’t respond to” issues he has raised.
Again, I will not walk into that debating trap and mechanically go through his 30 numbered arguments but will attempt to accommodate as much as is reasonable with some general comments and some specific replies.
Activism and science
This year the fluoridation issue raised questions about the problems of activism for a number of New Zealand scientists. The local scientific community was taken by surprise when the Hamilton City Council in June this year voted to end fluoridation. Surprised because most of us were unaware that the council had decided not to go ahead with a referendum (as we had expected) and instead use a “tribunal” process of consultation. This approach suites activist groups very well. They can be continuously in touch with council decisions, have a membership or contact base that can be organised rapidly and they can saturate such a consultation process with their own submissions.
The Fluoride Action Network of NZ (FANNZ) did this very well. They were able to dominate the consultation process with 89% of the total submissions. (This in a city where referenda have shown about 70% support fluoridation). Being part of Paul Connett’s Fluoride Alert Network they did this on an international scale – about 30% of their submissions were from outside Hamilton with many from outside New Zealand. People like Paul Connett and Declan Waugh made video submissions. These people were promoted as “international experts” or “world experts” on the subject even though they have no credible scientific publications on the subject. Of course local councillors did not have the background to see through that ruse. Reports prepared by the council staff showed the number and international origins of these submissions impressed the council and it’s bureaucracy.
It was easy to conclude that what local scientists lacked was a similar organised activist group. If not specifically devoted to defending the science behind fluoridation then at least to defending science in general. After all, anti-fluoridation activity is not the only area where science gets challenged.
Scientists and health professionals did become active in social communication activity, Facebook, letters to the editor, etc., but I noticed a distinct lack of enthusiasm for any organised activism. No one rushed to form an activist group.
Scientists have a problem with activism because the group thinking and selective use of scientific information inevitably involved is in direct conflict with the scientific ethos. That is why activist scientists tend to face disapproval from colleagues, although this has changed a little recently where the vicious personal attacks on individual climate scientists has made some form of scientific activism essential.
Confirmation bias and activism
Contrary to what many people believe humans are not naturally a rational species. Despite their intelligence and ability to reason they are in practice driven primarily by instinct and emotions. In fact, they would have long become extinct if they relied completely and in all cases on the inefficient and slow process of rationally considering every event that required a response.
This means that confirmation bias and cherry picking information come naturally to us. It is normal to seek information which supports the preconceived ideas and theories we are emotionally attached to. Scientists are just as prone to these human failings as others but the scientific processes help reduce this problem. Scientific ideas and hypotheses are tested by experiential evidence – they are compared against the real world. Theories are judged on their evidential support and not their attractiveness. (This does not deny an important role for speculation). Ideas and theories are exposed to harsh critical consideration by colleagues. All this helps to encourage objectively and reliability of scientific information – while not denying that there are still inevitable residual problems from confirmation bias. The dynamic nature of science and the provisional nature of current theories and ideas, means that over time mistakes arising from these human frailties can be reduced.
Contrast that with the position of activists, even scientific activists. They are inevitably driven by strong ideological or political aims which naturally encourage confirmation bias and cherry picking. But unlike a scientific researcher they exist in an uncritical, or at least biased, social environment. Group thinking encourages a selective approach to scientific knowledge and a resistance to considering anything conflicting with the activist agenda. While heretics can be encouraged in scientific research they get jumped on in activist groups. Ideas and messages do not get tested against reality – far from it. They are tested for political effectiveness, in the political arena – not the natural world.
In effect, the world of activism is stifling for a person used to the creativity of genuine scientific research. I recognise that at times activism is essential and have myself played an activist role in my past. Now I see it as a necessary evil but not something I could do as a job. I do not envy Paul Connett his job as an executive for an activist organisation. The environment of group thinking and the need to abandon intellectual honesty to the ideological aims of the group are bad enough. But what happens to a scientist in such a position who finds they can longer follow the “party line?” That they no longer “have the faith?” It is a bit like the priest who finds, after years in the job ,they are an atheist. Do they go on hypocritically preaching every Sunday or do they take the honest way out and abandon their job with it’s financial and social security to face an uncertian future?
In scientific research it is expected that we can change our beliefs and ideas in the face of new evidence. Not to do so could lead to loss of scientific prestige and employability. It is the reverse to what Paul would face if he lost his anti-fluoridation convictions.
That is the problem for me – the strong pressure to conform to the activist ideological agenda despite the evidence. I think that colours Paul’s approach to many of the issues in his articles here.
Paul raises the misleading image that was in a Queensland Health brochure again. He sweats blood attempting to imply my approval of that tactic. That is not honest. Especially as I made clear that “I do not support its implied message.” And explained that Paul’s Queensland Health example, and a similar anti-fluoridation brochure I raised, are “extreme exaggerations used to promote a message. Reasonable people should condemn that tactic. “
It is interesting Paul devotes so much time on this brochure in his last contribution to what, after all, is meant to be a scientific exchange, not an exercise in laying guilt for someone else’s transgression. No one is actually defending the Queensland Health brochure – even Queensland Health! At this stage it seems purely to be a plaything of the anti-fluoridation groups. Paul himself was unable to supply a source or citation yet he had ready access to it and promotes it far and wide.
Don’t know what else I can add – except writing personally to Queensland Health with a complaint. Bit difficult without a citation to its use I could quote. Never mind, my public admonishment here should suffice.
I agree with Paul that we should expect better from our public servants but Paul missed my point “This sort of misrepresentation is probably more common among opponents of fluoridation.” I certainly find misrepresentation by public officials on this subject rare – anti-fluoride activists make this charge far more often than is justified.
I do not buy Paul’s argument that similar but much more common misinformative propaganda by anti-fluoridation activists is somehow more permissible than the rare piece by a public servant. Especially as we have the power to correct a public servant, submit a freedom of information application, get a retraction and an apology. But try that with anti-fluoride activists and organisations like FAN and FANNZ. No such luck. One is more likely to be abused.
Paul’s complaints in this area would be a bit more convincing if he publicly condemned the misleading propaganda from his own activists. He cannot be unaware of the extreme claims made by members of his Fluoride Alert Network throughout the world. Quite apart from their misrepresentation of the science, which he probably encourages anyway, there are the political and personal harassment of people by sections of his activist network which he cannot be blind to, yet refuses to condemn.
I have yet to see him condemn the atrocious propaganda, lies and personal attacks of propagandists like Alex Jones and Vinny Eastwood. It is not enough to say he doesn’t necessarily support all their positions. The fact that he uses their services, and they use his, makes such weak dissociation disingenuous.
Why is he unwilling to publicly condemn such behaviour?
The Hastings trial
Paul weaves a conspiracy theory around the Hastings’ trial using on one-sided sources and their vague claims. I note that Paul also relies on quotes from letters. He does the same in his book. A colleague analysed the reference list and found many are to newspapers, magazines, newsletters, letters and conversations in meetings (a large proportion are duplicates) (see an impressive-sounding number of references, (therefore good?)). Yet he proudly says “You will note that every argument in this book is backed up with references to the scientific literature – 80 pages in all.”
I don’t think such vague charges should be the subject of our scientific exchange – especially as they divert attention from the scientific issues involved in planning and interpreting such trials and epidemiological studies. Paul should have looked at the disputes around Colqhoun’s analysis of the New Zealand data. Colqhoun was strongly criticised for reliance on questionable data, crude measurements of caries prevalence and failing to establish residence histories and therefore reliable measures of fluoride intake (see, fir example, Newbrun & Horowitz, 2002). He also placed far more reliance on longitudinal studies than is warranted and was selective in choosing studies which have compared fluoridated and unfluoridated communities.
I looked at the current NZ data, which are similar to that analysed by Colqhoun, in my article Cherry picking fluoridation data. This illustrates a number of things. The national data shows clear differences between children from fluoridated and unfluoridated communities and an ethnic effect attributed to social and economic deprivation. This is just normal school clinic data, without technique standardisation for those making the measurements or proper recording of place of residence. The latter effect probably shows up more strongly after 2004 when a “hub and spoke” dental clinics system was introduced further confusing proper records of likely fluoride intake because one clinic could serve a number of areas – both fluoridated and non-fluoridated. This is a likely explanation for the apparent decline of the effectiveness of fluoridation after 2006.
To illustrate how easy it is to extract data for regions and cities which give meaningless results the plot below shows the data for the Waikato. Clearly the variability in this data, (indicated by abrupt changes year to year) is so large it make interpretation meaningless. Yet this does not stop FANNZ, the local version of Paul’s activist organisation, from hypocritically using just the 2011 data for the Waikato (where by chance children from fluoridated areas show more caries than unfluoridated!). One of their representative end used my graph below, showing the problem of cherry picking, as “proof” for claiming fluoridation increases incidence if caries. During the recent referendum campaigns this misrepresentation by anti-fluoridation activists was rife – yet they consistently ignored or covered up the national data.
There is a lesson in this. Careful and critical analysis of epidemiological data is necessary when considering such data. Effects of technique standardisation and changes, places of residence, mobility of families and diffusion of products from fluoridated into non-fluoridated areas must be considered.
Too often anti-fluoride activists simply select the data that fits their story better. They may even be unaware of what they are doing because confirmation bias is a trap we can all fall into and it can be very tempting if one is simply looking for plots to illustrate an effect. To be fair, I have even seen proponents of fluoridation fall into this trap occasionally.
Margin of safety
Paul mentions margin of safety a lot. He claims that I did not comment on the margin of safety analysis he provided based on the Xiang et al. (2003a,b) study.
Has he not been reading my side of the exchange?
I had put a question to him on his use of this study to determine a margin of safety. After commenting on the quality of the study and the journal Fluoride where it was published I wrote:
Yet Paul uses Xiang’s paper to authoritatively claim it had “found a threshold at 1.9 ppm for this effect.” (What effect he refers to is unclear.) How reliable is that figure of 1.9 ppm (actually 1.85 or 2.32 ppm F in the paper) – considering the huge variation in the data points of the Figure 1? (Unfortunately the paper is not a lot of use in explaining that figure – reviewers should have paid more attention.)”
Paul did not respond so I repeated my question in a subsequent article asking him “about the huge variability in the data and how the hell one can place any confidence on the result drawn from Xiang’s figure.”
Briefly my question related to the figure used by Xiang et al.
This is just another example Paul’s selective use of the literature and selective interpretation of parts of it to justify a preconceived claim he wishes to make. In practice, safety limits and margins of safety must be based on a far more extensive review of the literature and involve far less hand waving than Paul demonstrates in this case.
Bottle fed babies – misinformation again
Several times Paul has raised the issue of bottle-fed infants without describing the problem. Broadly, he is making the common anti-fluoridation claim that the reliance of bottle-fed infants on formula made up with fluoridated water causes normal limits for maximum F intake to be exceeded. Usually activists using this argument will refer to health authorities which they claim recommend that formula not be made up using fluoridated water.
The science for the New Zealand situation is clearly described by Cressey et al (2009) in their report Estimated Dietary Fluoride Intake For New Zealanders by Peter Cressey, Dr Sally Gaw and Dr John Love. It is a straightforward desktop study of the “dietary fluoride intakes for a range of age and gender sub-populations based on New Zealand data.” This is how they described their findings for formula-fed infants:
“The estimates for a fully formula-fed infant exceeded the UL [upper level of intake] approximately one-third of the time for formula prepared with water at 0.7 mg fluoride/L and greater than 90% of the time for formula prepared with water at 1.0 mg fluoride/L. However, it should be noted that the current fluoride exposure estimates for formula-fed infants are based on scenarios consistent with regulatory guidelines, rather than on actual water fluoride concentrations and observed infant feeding practices..”
They conclude “the very young appear to be the group at greatest risk of exceeding the UL.” However:
“the rarity of moderate dental fluorosis in the Australia or New Zealand populations indicates that current exceedances do not constitute a safety concern, and indicates that the UL may need to be reviewed.”
They are conceding that in some cases, some of the time, recommended upper levels for fluoride intake can be exceeded for fully formula fed infants. However they do not see this as a real safety concern.
These conclusions lie behind the current advice from our Ministry of Health on this subject. This takes account of the need for review of current ULs and considers use of fluoridated water safe for fully formula-fed infants. However, they also recommend that if parents are concerned (such as over the risk of dental fluorosis) they should use non-fluoridated water for part of the feeding – a peace of mind matter.
The situation in the US is similar
American Dental Association advises:
Yes, it is safe to use fluoridated water to mix infant formula. If your baby is primarily fed infant formula, using fluoridated water might increase the chance for mild enamel fluorosis, but enamel fluorosis does not affect the health of your child or the health of your child’s teeth. Parents and caregivers are encouraged to talk to their dentists about what’s best for their child.”
Where parents want to reduce the risk of dental fluorosis they:
can use powdered or liquid concentrate formula mixed with water that either is fluoride-free or has low concentrations of fluoride.
And the CDC advises:
Yes, you can use fluoridated water for preparing infant formula. However, if your child is exclusively consuming infant formula reconstituted with fluoridated water, there may be an increased chance for mild dental fluorosis. To lessen this chance, parents can use low-fluoride bottled water some of the time to mix infant formula; these bottled waters are labeled as de-ionized, purified, demineralized, or distilled.
This sort of information is often distorted by anti-fluoridation activist propaganda. Very often they claim that authorities like the CDC are recommending as an absolute that parents use non-fluoridated water in preparing formula for infants, and not treat the issue as a peace of mind matter.
Anti-fluoridation activists almost unanimously quote figures for total dental fluorosis (or its equivalent) lumping together everything from questionable to severe. This gives them a nice high figure to promote. But, as I have said before, they use a bait and switch tactic to exaggerate the seriousness of the problem by then considering only the more severe category’s when considering the harm. It is worth actually listening to the anecdotal evidence of practicing dentists on this specific issue. How often do they see fluorosis or similar blemishes which need treatment? And how does this figure compare with the frequency with which they see dental decay serious enough to need treatment? I can think of only one dentist who claims fluorosis is a problem which he often sees and treats – he is an active propagandist for FANNZ. I have caught him telling many porkies about fluoridation and I wouldn’t trust his claims.
Paul attempts to put words in my mouth saying I “claimed there was practically no difference in dental fluorosis prevalence between fluoridated and non-fluoridated communities.” I did point out that the most recent NZ Oral Health Survey found no measurable difference. But I also acknowledged that in general an increase in mild categories is normally observed with fluoridation. What I actually wrote was:
“the incidence of fluorosis for children living in fluoridated may often be the same as, or only slightly greater than, the incidence for children living in non-fluoridated areas.”
This is not a denial of an increase in mild forms of fluorosis as a result of fluoridation. Nor is if a denial that the relatively small difference may reflect the diffusion of the benefits of fluoridation into the non-fluoridated areas through family mobility, poor representation of residence history and the movement of products prepared with fluoridated water.
Paul’s misrepresentation is not the sort of behaviour I expect from a discussion partner in a scientific exchange.
All Paul’s manipulation of figures and his claimed access to the minds and “potential psychological problems for young teenagers” does nothing to change the basic situation. This is that water fluoridation can cause an increase in the mildest classification of dental fluorosis but is generally not thought responsible for the more severe classifications. The later are relatively rare and any increases over recent years is unusually attributed to the wider use of fluoridated toothpaste and fluoride dental office treatments (and their accidental ingestion).
The common anti-fluoridation propaganda gives the impression that the total fluoridation occurrence quoted is all severe and not almost all very mild or questionable. For example, in New Zealand activists often use the figure of 44% occurrence of dental fluorosis when only 2.5% is of any concern.
I have said again and again that one should attempt to understand the scientific literature intelligently and critically. Hard to do as we all suffer from conformation bias and can’t help being selective. Fortunately working within a scientific community there is pressure from peers who will challenge ones interpretation. This helps encourage objectivity and honesty.
But working in an activist group one does not experience such challenges. If anything there is the challenge to conform with the group thought. Confirmation bias and cherry picking gets encouraged and rewarded. Paul’s activism and bias is very clear in the way he selectively quotes the NRC (2006) report. Just a few examples from his last article in his attempt to justify conclusions he wishes to draw from animal studies using high fluoride concentrations.
“Dunipace et al. (1995) concluded that rats require about five times greater water concentrations than humans to reach the same plasma concentration. That factor appears uncertain, in part because the ratio can change with age or length of exposure. In addition, this approach compares water concentrations, not dose. Plasma levels can also vary considerably both between people and in the same person over time (Ekstrand 1978).” (My emphasis of the bits Paul omitted).
Similarly with Paul’s second quote from the NRC report:
“Because many assumptions were involved in estimating the values presented in Table D-2, they should be used with caution. But values support a rat-to-human conversion factor for bone fluoride uptake of at least an order of magnitude.” (My emphasis of the bits Paul omitted).”
Natural and artificial fluoride
Many of people relying on Fluoride Alert for their information are confused about the nature of the hydrated fluoride anion in water. At the mystical end of this confusion is the concept that chemical species derived from man-made process are different in their biological action to that from natural sources, even though chemically there is no difference. At the more “realistic” end there is a refusal to accept that the fluorosilicate anion decomposes on dilution. Then there is the hand waving over the role of calcium that Paul indulges in. He repeats his claim:
“Usually when fluoride occurs naturally in the water it is accompanied by large concentrations of ions like calcium. The presence of the calcium can reduce the uptake of fluoride in the stomach and GI tract. No such protection is offered when the fluoridating chemicals are added to soft water.”
I have had to repeatedly battle out this argument with anti-fluoridation activists who obviously don’t understand basic chemistry but I find this statement amazing for a chemist who should understand the concept of solubility products and the nature of ions in solution.
Contrary to Paul’s suggestion the relationship observed between natural Ca and F concentrations in groundwaters is usually inverse – F concentrations increase as Ca concentrations decrease and vice versa (see for example Handa 1975 – Geochemistry and Genesis of Fluoride-Containing Ground Waters in India). Just what we expect when a solid phase like fluorite or apatite is determining solution concentrations at equilibrium.
Here is what one of the commenters on Paul’s last article, Jo Lane, has to say about Paul’s denial of the presence of Ca in treated fluoridated water:
“Point 20 ) Classic example of pseudoscience. Let’s assume that Paul is correct in asserting that the presence of Ca2+ ions affects F- uptake in the GI tract.
Municipal water supplies in NZ have a target hardness (combined concentration of Ca2+ and Mg2+ ions) of 200 mg L-1. Most of this is Ca2+ as Lime (CaO) is typically used to increase pH in one of the final stages of water treatment.
If water was fluoridated to 0.8 mg L-1 F- (unreasonably assuming there is 0 mg L-1 F- to start with) using CaF2 as a source, the concentration of Ca2+ would increase by 0.2 % as compared to using HFA or NaF as a source of F-. This 0.2% change in Ca2+ concentration will not have any appreciable effect on F- uptake in the GI tract.
Given Paul has a PhD in chemistry I cannot believe that he is ignorant of such basic chemistry and so I am left with the unfortunate impression that he is being deliberately deceptive in the way that he presents his arguments.”
I agree. Sure, the Ca concentration in community water supplies will generally be lower than the target value (which is a maximum) but the principle remains. Replacement of fluorosilicic acid by fluorite (CaF2) as a fluoridating agent would have a minuscule effect on calcium concentrations because there is plenty of calcium from other sources – even is soft water.
Paul’s claim is the sort of thing that even an educated chemist might say if they are ideologically driven. This is the problem with activist groups with their own ideological demands and group thinking. It is easy for even the trained person to fall in to an opportunist use of their speciality. And if, like Paul, they are working as an executive of an activist group they don’t have anyone around them to challenge such distortions.
Irish data and reliance on inter-country comparisons
I am pleased Paul admits to being “hasty” in his dismissal of the Irish data. But there are two issues.
1: His problem was more than haste – I was objecting to his attempt to belittle the data by suggesting the Irish workers were biased. I expressed surprise that he would reject the data with that suggestion in a scientific exchange.
2: He appears confused – despite my clear explanation of the data I used. These was the same as used by Cheng et al (2007) – for just one country (Ireland) but separated into the fluoridated and unflouridated areas – not just using the average that Cheng et al used). Paul describes the data as “comparing tooth decay in the Republic of Ireland and Northern Ireland.” Clearly it did not.
Perhaps Paul’s fixation with Declan Waugh’s discredited comparisons of the health statistics for the two countries was pro-occupying Paul’s mind – or perhaps he wanted to divert the discussion into that area.
I repeat the comparison I used below.
The dotted line in the RH figure is effectively what Cheng et al (2007) used for Ireland in the LH figure.
At the time I explained the problems in making the inter-country comparisons Paul was insisting on:
“Simple comparison of countries obscures all sorts of effects such as differences in culture, history, social and political policies, etc. Such plots are also influenced by changes and differences in dental treatment and measurement techniques.”
However, as Paul raises the issue again it is worth commenting again on the flippant way he and other anti-fluoridation propagandists use inter-country comparisons like this. This is the hand-waving involved in claiming the data shows no effect of different fluoridation policies. I will use a figure from Paul’s book to illustrate the problem.
Paul claims his figure shows no difference between the countries – but did he do anything to check that? Did he actually measure the slopes for the different countries? Or did he just wave his hands and say there is clearly no difference?
Fortunately with so few countries it is relatively easy to compare the slopes. I have done so using the data from the WHO site and found the average decline was 0.17 DMFT/year for fluoridated countries and 0.13 DMFT/year for the non-fluoridated countries. This suggests the decline of DMFT in the fluoridated countries was about 25% greater than in the non-fluoridated countries.
Local anti-fluoridation activists reacted strongly to my analysis claiming it is obvious that the analysis is useless. I am sure Paul will point out that the figure of 25% will not be statistically significant – and I agree. The scatter in the rates of decline among the different countries is very large. On top of that the original data itself is hardly very good with generally only 2 data points for each country.
But if the variation is great enough to make a 25% difference in slopes non-significant then what value do such figures have for Paul’s argument? Using simple hand waving and eye-balling to claim no difference is deceptive because he hides that variation. We just don’t expect such comparisons to show the differences due to fluoridation policies. Variation and the influence of confounding factors have too great an influence.
Paul continues to ignore systemic role
Although he concedes it wrong to create the impression that the current surface or topical mechanism for the beneficial role of fluoridated water on existing teeth is the only mechanism he still persists in ignoring any role for ingested fluoride. Any systemic effect. He asks “why are we forcing people to swallow fluoridated water at all?” He ask why I am “not merely advocating swishing and spitting out fluoridated water, or fluoridated mouthwash or using fluoridated toothpaste.”
I have answered that question several times but Paul continues to ignore my response. He claims my description of the normal and natural role of fluoride in bioapatites do not get is anywhere. He ignores my reference to scientific reports of the participation of ingested fluoride in improving oral health, especially through its beneficial role before teeth erupt.
Unfortunately Paul cannot get past his emotive description of a social health policy as “forcing” something on people. His naive assertion that normal consumption of water should be replaced by “swishing and spitting out” or by a mouthwash or toothpaste also shows he just does not understand the nature of a social health policy. I discussed this in more detail in my last article.
Hirzy’s conspiracy theory
Paul’s colleague in FAN, Bill Hirzy, is unhappy about my reference to his use of a conspiracy theory – the claim that fluoridation is used as a way of disposing of industrial waste. I was referring to Bill’s claim in his section of Paul’s article:
“Water fluoridation, especially with FSA in the U.S., is not at all about improving dental health; it is rather about U.S. taxpayers paying phosphate producers billions of dollars for the privilege of having our public drinking water systems used to dispose of an acid that would otherwise have to be managed in a hazardous waste facility, and thereby improving the bottom lines of phosphate producers.”
He defends himself by attempting a diversion into USGS data showing 94% of fluoroslicic acid produced as a byproduct by phosphate manufacturers goes to water fluoridation systems.
I don’t doubt those figures. M. Michael Miller, in his article Fluorspar gives similar data for 2004:
“About 38,700 t of byproduct fluorosilicic acid valued at $5.15 million was sold for water fluoridation, and about 1 2,300 t valued at $2.71 million was sold or used for other uses”
Miller’s 75% of byproduct fluorosilicic acid sold for water fluoridation is lower that the 94% Hirzy quotes but the difference could result from some of the material being converted to other products before sale.
So, if a quarter of byproduct fluorosilicic acid, or its conversion products, find markets other than water fluoridation what is it about this quarter which makes it a valuable, saleable product – while the 75% sold for water fluoridation must be classified as a waste product and need a conspiracy for its disposal?
Extensive possibilities for fluorosilicic acid uses
As mentioned above there is certainly a market for fluorosilicic acid,and it’s conversion products, apart from use as a water fluoridation agent. I believe that market will probably increase further because the decline in fluorite sources will increase the use of phosphate ores as a source of fluorine chemicals. This will mean that fluorosilicic acid will become more commonly used as an intermediate in the preparation of many, if not most, fluoride chemicals produced.
Currently fluorosilicic acid can be used in the tanning of animal hides and skins, oil well acidifying, electroplating, glass etching, as a commercial laundry sour, sterilising agent, in cement and wood preservatives, in the manufacture of ceramics, glasses and paints, in lead refining, etc. it can also be used to manufacture hydrofluoric acid, another important industrial chemical and intermediate for many other fluorine compounds. It can also be converted to aluminium fluoride and cryolite which are important in the conversion of alumina ores to aluminium metal.
Ultimately the fluorosilicic acid byproduct from the phosphate industry could become the Teflon on your frying pan, the refrigerant compound in your refrigerator or incorporated in the many products you use every day.
Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.