Tag Archives: Drinking water

Fluoride debate Part 1: Perrott

This is Ken Perrott’s response to Paul Connett’s first article – Fluoride debate Part 1: Connett.

Paul’s first article appears to be a general overview and not detailed consideration of the ten points he makes. I will be similarly brief in my response to each point. Paul may wish to go deeper into specific issues in later contributions and I will respond in more detail then.

 The medical argument

Paul’s first 3 arguments rely on defining fluoridation as a medical treatment. This is a common anti-fluoridationist approach. I have no wish to argue about that definition as it is really just a matter of semantics. You could use a weak definition of “medicine” which can include practically anything in your diet the body uses and may tolerate over a wide range of intake without harm. Or a tighter definition implying a drug with some sort of marked effect in the body and requiring relatively careful control of intake. But whatever definition is used should be openly declared and applied consistently.

Opponents of fluoridation usually apply their definitions of “medicine” inconsistently and the argument becomes a classic bait and switch tactic. It uses a weak definition of “medicine” to capture fluoride and then switches to a tight definition to argue that use of fluoride requires rigid controls. This presents them with a number of problems because a weak definition of “medicine” must also include “natural” as well as “artificial” fluoride at natural levels in water a food. (A weak definition may also include many other elements – perhaps even water itself). There is no such thing as a “fluoride-free” water supply. If we exclude natural levels of fluoride (and most other elements) from our definition of “medicine” then why should we treat levels for artificially fluoridated water any differently?

Connett’s point 1: Why should we not be concerned about controlling the dose of natural levels of fluoride (or many of the other elements we consume) while only be concerned about the fluoride added as a “top up?” The are no differences between the “artificial” and “natural” fluoride anions in drinking water. In reality most elements like this have a sufficiently wide range of concentrations and intakes for efficacy that it is just ridiculous to treat them like powerful drugs which need accurate dosage.

Connett’s point 2: Similarly why make charges of indiscriminate intake only for artificially added F and not for natural levels of F and other elements? The small number of people, if any, who may have problems with fluoridation levels of F will also have the same problems with natural levels of F. Such people, if they real exist, will need individual responses to either natural or artificial levels of F and possibly other elements. These people will need individual responses whether their water supply is artificially fluoridated or not.

Connett’s point 3: Why demand “informed consent” for situations where natural levels of fluoride have been “topped up” and not require it for natural levels of fluoride – which in some situations may actually be higher than for fluoridated water supplies.

 Is fluoride a nutrient?

 Connett’s point 4: This also reduces to semantics – how should “nutrient” be defined? Paul restricts his definition only to elements involved in “biochemical processes” – a definition confidently excluding the role of F in bioapatites – bones and teeth. Yet bones and teeth are important to organisms – so the strengthening of bioapatites, and the reduction of their solubility, by incorporation of fluoride is important.

Perhaps we can agree that F is at least a beneficial element, even if we can’t reach agreement on the use of terms like “nutrient” and “essential.”

 Biochemical processes and fluoride

 Connet’s point 5: It is easy to cite literature references showing negative effects of fluoride but we should not ignore the conditions used. Most such studies refer to much higher concentrations than used in water fluoridation and this is also true for the review by Barbier et al, 2010 Connett cites.

Let’s not forget that community water fluoridation describes “topping up” fluoride concentrations to about 0.7 ppm F. Yet reviews of negative effects on biochemical process will quote studies which have used 50 ppm, 100 ppm or even greater concentration of F in drinking water. Opponents of fluoridation often seem completely oblivious of these huge differences in concentration when they present a long list of claims about the ill effects of fluoridation.

Another confusion readers often have with such reviews is the use of different units. The sensible reader must often apply a few conversion factors when checking the fluoride concentrations used in the reviewed studies. 1 mM = 19 ppm (or mg/L) for fluoride.

It is possible to find similar evidence of harmful effects of essential elements when present in high concentrations. Selenium is an example of such an essential element. This graph illustrates the situation for fluoride and is common to many elements.

Diagram from Ethan Seigel’s blog Starts with a Bang (see Weekend Diversion: Fluoridated Water: Science, Scams and Society).

I am not denying the usefulness of these studies of negative effects of fluoride. Researchers and policy makers should continuously assess research findings for their relevance to the fluoridation issue and guidelines used in regulations. But this assessment must be critical and intelligent – not simply a search to confirm biases.

Health authorities should not be swayed by populist naive interpretations of research.

 Naturalistic fallacies

 Connett’s point 6: Sure, organisms evolve to fit the parameters of their environment. But to say “it is more likely that nature knows more about what the baby needs  than a bunch of dentists  from Chicago or public health officials in Washington, DC” is really not a good way of deciding this issue. Do we really want to argue that the situations in which marine animals evolved are the best to aim for in a society which has undergone so much cultural and intellectual evolution? Are we to reject the idea that society should task experts to consider possible approaches for our future by the argument that “nature knows best” and give up all rights for humanity to improve its condition? Do we really think that the environment that ancestral species experienced millions of years ago are necessarily the best for us today?

Modern humans live in environments offering a range of natural dietary fluoride intakes. We know that very low or very high intakes present problems for our bones and teeth. We should not avoid the problems this presents by saying “nature knows best.”

The very low levels of F in breast milk may have more to do the with inorganic role of F in animal bodies than any wisdom that “nature” has.


Proponents of fluoridation do acknowledge dental fluorosis in a negative, although minor, aspect of fluoridation.

 Connett’s point 7: Opponents of fluoridation will often quote high values of the incidence of fluorosis which ignore the fact that much of it is “questionable” and/or “very mild.” These grades are really only cosmetic and usually can only be detected by a professional. Opponents may also hide the fact that 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.

The graphs below shows the situation reported for New Zealand in the 2009 New Zealand Oral health Survey (see Our Oral Health).


See Wikipedia for a  brief description of Dean’s Fluorosis Index.

Health experts have generally concluded that the apparent rise in the incidence of fluorosis is caused by increases in other forms of fluoride intake, such as from eating toothpaste, and not from fluoridated water.

Fluorosis could well have been a normal feature of teeth and bones for a very long time. Remember many areas of the world are high in natural forms of fluoride and the body does not seem to have a process for fine regulation of blood and plasma fluoride concentrations. Perhaps we should consider very mild and questionable levels of fluoride as cosmetically perfectly acceptable. Considering the natural variation in fluoride intakes some people might argue that “nature knows best.”

Nature of fluoridating chemicals

Connett’s point 8: Anti-fluoridationists make wild claims about fluoridation chemicals. “They are industrial waste products, loaded with heavy metals and fluorosilicates are toxic and/or untested for toxicity!”

Claims of contamination with toxic elements are easily, and often, made but are never justified with any evidence. So lets look at the reality.

By-products that are used are not waste products – and surely we should aim for the efficient use of natural resources. The purchaser of any product will sensibly make sure it is suitable for their requirements – and these are rigidly defined for water treatment chemicals.

Suppliers are required to provide certificates of analysis and maximum values for contaminants in chemicals used for water treatment. Those regulations are determined from the maximum concentrations of contaminants allowed in the finished water for human consumption. Safety factors are also involved as well as allowance for contribution from other sources.

The table below contains analytical data for contaminants taken from certificate of analysis for the last batch of fluorosilicic acid used in the Hamilton, New Zealand, water treatment plant (see FSA column). I compare the data with the maximum allowed impurity levels of fluorosilicic acid defined in the regulations (Impurity limits column) and with an example of the contaminant concentrations in finished water (Drinking water column).

Toxic Element Impurity limits* FSA** Drinking water**
Sb (ppm) 40 <0.09
As (ppm) 132 0.4 <0.002
Cd (ppm) 40 0.11 <0.001
Cr (ppm) 660 0.8 <0.001
Hg (ppm) 26 < 0.05 <0.001
Ni (ppm) 264 < 1 <0.001
Pb (ppm) 132 0.8 <0.001

* Maximum acceptable contamination.
** From Certificate of Analysis
***For Gear Island Treatment Plant, Greater Wellington region.

There are several points to make.

1: These concentrations are extremely low, meaning that the final concentrations in the finished water are insignificant.

2: For comparison, column one provides the maximum permissible concentrations allowed for fluorosilicic acid used for water treatment ( NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997. ).

3: The NSF,which regularly monitors contaminants in water treatment chemicals says in this year’s NSF Fact sheet on fluoridation: 

“In summary, the majority of fluoridation products as a class, based on NSF test results, do not contribute measurable amounts of arsenic, lead, other heavy metals, radionuclides, to the drinking water.”

And the NZ Waste Water Association’s report says:

“Commercially available hydrofluorosilicic acid, sodium fluoride and sodium silicofluoride are not known to contribute significant quantities of contaminants that adversely affect the potability of drinking water.”

Brown, Cornwall & McPhee, 2004 say in their review paper, Trace contaminants in water treatment chemicals: sources and fate:

“ Coagulant chemicals are the main source of trace metal contamination in water treatment.”

4: Some people seem to think that simply quoting concentration  of contaminant species is proof of contamination – irrespective of the actual magnitudes. I have seen speakers flash up a slide listing heavy metal contents without bringing notice to the actual concentrations. That is silly. Our environment, no matter how “natural,”  will always contain some amount of contaminant chemicals – it is the actual amount that is important – not that it can be, or is, measured.

Arsenic in community water supplies

Paul raises the problem of arsenic and this provides an opportunity to put the contaminants in fluorosilicic acid into context. The table shows that As levels are typically very low in fluorosilicic acid used for water treatment (0.4 ppm As). In my article Hamilton – the water is the problem, not the fluoride! “ I show that in the local Hamilton, New Zealand, situation the source water from the Waikato River is the major source of As in the finished water – several orders of magnitude greater than for than from treatment chemicals.

Anti-fluoridationists often rely on a recent paper by  Hirzy et al. (2013) for their claims about As in fluoroslicic acid and it’s effect on the incidence of cancer. Hirzy has since acknowledged errors in his calculations and described himself as embarrassed by them and his mistake about cancers. A petition to the EPA which used his data to  argue against use of fluorosilicic acid in water treatment was rejected partly because of these errors (see Anti-fluoridation study flawed – petition rejected).

Fluoridation data around the world

Connett’s point 9: Yes, a few countries do not fluoridate their water community supplies for political reasons, but decisions against water fluoridation can depend on a range of factors including size and centrality of water treatment plants, widespread use of bottled water, naturally sufficient water fluoride concentrations, etc.

Paul refers to a plot used by Cheng et al (2007) – which is similar to this one:

This and similar plots are much beloved but anti-fluoridation propagandists. But while the plots do show improvements in oral health for countries irrespective of fluoridation they say nothing about the effect of fluoride. 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, there are some within country data within the WHO data set Cheng et al used which can give a better idea of the beneficial effects of fluoridation. This plot shows the results for the WHO data for Ireland. A clear sign that fluoridation has played a beneficial role.


Political and scientific arenas.

Connett’s point 10: The debates around fluoridation involve both scientific and political issues. Inevitably this leads to the separate issues being mixed. I find, for example, that attempts to discuss the ethical aspects always get diverted into differences in understanding of the science. For example the paper Ethics of Artificial Water Fluoridation in Australia by Niyi Awofeso is meant to be a description of the ethical issues. However, it assumes mistaken ideas about the science – that fluorosilicate species are present in fluoridated drinking water. Without the correct science it is so easy to end up with invalid ethics.

Appeal to authority is also a problem. Connett does this, for example, in his reference to Prof. James Summer, Nobel prize winner. Similarly wild claims are often made about Nobel prize winners and “top scientists” opposing community water fluoridation  – these are really not valid arguments.

I feel that opponents of fluoridation commonly rely more on confirmation bias than critical and objective assessment when referring to the scientific literature.

There is also a reliance on conspiracy theories and poisoning of the well. We have seen personal attacks on scientists and health authorities in New Zealand when they have spoken up to defend the science. Childish name calling, accusations of being paid to make incorrect claims, charges of being “shills” for industry, etc. This is simply “playing the man and not the ball” and makes good faith discussion of the science impossible.

This even gets into peer-reviewed scientific literature. The authors of the paper Connett refers to, Cheng et al 2007, do this when they accused one side, that of health authorities, of “questionable objectivity.” Pots and kettles?

All of these problems are probably inevitable for an issue like this where political and ideological interests operate. But they are an anathema to proper scientific consideration.

Professor Gluckman, the NZ Prime Ministers Chief advisor on Science commented that fluoridation controversies were an example of science being a proxy for values/political issues. This leads to misrepresentation of the science, cherry picking of data, and relying on confirmation bias and google for literature searches. Ideology and values are the motivating factors but a caricature of science is used in the debate.

Good faith discussion of the scientific issue around fluoridation requires much more objectivity than  is usually demonstrated by the opponents of fluoridation.

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.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page

Fluoridation: the hip fracture deception

Warning – this book is deceptive

One of the myths promoted by the anti-fluoride people is that fluoridation is bad for our bones. As with similar myths the evidence used to support the claims usually comes from studies of situations where people have high F intake, often from natural sources.

However, there are studies which anti-fluoridationists can quote which do relate to fluoridated water concentrations.  For example, this is one of the many claims made by Christopher Bryson in his book The Fluoride Deception. This book tends to be used as scripture by anti-fluoridationists today so I thought I would look a bit more deeply into his claim.

Such deeper looks can often show problems of confirmation bias or uncritical evaluation of the literature – it did in this case.


Bryson based his claim solely on work by Joseph Lyon, in particular the paper Hip Fractures and Fluoridation in Utah’s Elderly Population by Christa Danielson; Joseph L. Lyon; Marlene Egger; and Gerald K. Goodenough (1992). However, he does claim  “subsequent studies have found similar associations between fluoride in water and bone fractures.”

Danielson et al. concluded:

“We found a small but significant increase in the risk of hip fracture in both men and women exposed to artificial fluoridation at 1 ppm, suggesting that low levels of fluoride may increase the risk of hip fracture in the elderly”


Well, it doesn’t take much searching to find papers with contrary conclusions. For example Community water fluoridation, bone mineral density, and fractures: prospective study of effects in older women by
Kathy R Phipps, Eric S Orwoll, Jill D Mason, Jane A Cauley (2000).

They concluded:

“Long term exposure to fluoridated drinking water does not increase the risk of fracture.”

So different conclusions, but why? Well Phipps et al. allude to the causes of contradictory conclusions in their introduction.

“While the benefit of fluoridation in the prevention of dental caries has been overwhelmingly substanti­ated, the effect of fluoridation on bone mineral density and rates of fracture is inconsistent. Ecological studies that compare rates of fracture specific for age and sex between fluoridated and non­fluoridated communities have variously found that exposure to fluoridated water increases the risk of hip fracture, (here they refer to Danielson et al 1992) increases the risk of proximal humerus and distal forearm fracture, has no effect on fracture risk, and decreases the risk of hip fracture. Ecological studies, however, have a major design flaw—they are based on community level data and cannot control for confounding variables at the individual level.” (My emphasis).

In contrast:

“We determined, on an individual level, whether older women with long term exposure to fluoridated water had different bone mass and rates of fracture compared with women with no exposure.” (My emphasis).

And they concluded:

“This is the first prospective study with adequate power to examine the risk of specific fractures associated with fluoride on an individual rather than a community basis. Our results show that long term exposure to fluoridation may reduce the risk of fractures of the hip and vertebrae in older white women. Because the bur­den of osteoporosis is largely due to fractures of the hip, this finding may have enormous importance for public health. If fluoridation does reduce the risk of hip fracture it may be one of the most cost effective meth­ods for reducing the incidence of fractures related to osteoporosis. In addition, our results support the safety of fluoridation as a public health measure for the con­trol of dental caries.”

So, if we compare the results from the two studies we see that while Danielson et al (1992) reported an increase in the risk of hip fracture for women drinking fluoridated water, Phipps et al (2000) actually reported a decrease in the risk. The difference being that Phipps et al (2000) removed confounding factors such as  medical history, drugs and supplements, reproductive history, menopause, alcohol consumption, exercise, smoking, caffeine intake, height and weight.


Relative risk of hip fracture for women with fluoride exposure compared to women with no fluoride exposure


While preparing this I noted a new paper on this subject just published – Näsman et al (2013) “Estimated Drinking Water Fluoride Exposure and Risk of Hip Fracture:A Cohort Study

The abstract reports:

“Estimated individual drinking water fluoride exposure was stratified into 4 categories: very low, < 0.3 mg/L; low, 0.3 to 0.69 mg/L; medium, 0.7 to 1.49 mg/L; and high, ≥ 1.5 mg/L. Overall, we found no association between chronic fluoride exposure and the occurrence of hip fracture. . . . fluoride exposure from drinking water does not seem to have any important effects on the risk of hip fracture, in the investigated exposure range.”

So extra support for the conclusion that fluoridation does not lead to increased risk of hip fracture.

Motivated cherry picking

I think this shows the danger of cherry picking studies to support a preconceived position. And of relying on individual sources, or ideologically motivated sources like  The Fluoride Deception, for information.

There is a large amount of research on fluoride which to the uninitiated must seem contradictory. Proper review of this literature requires skills in critical thinking, and background in the field. The sort of thing that activist groups, and local body councils, don’t have.

Of course, I have no special background in this area either – and I don’t pretend that my summary here is at all definitive. However, it does show how misinformation can easily be promoted, with an apparent respectability conferred by  scientific references, when motivated people cherry pick.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

Hamilton – the water is the problem, not the fluoride!

Saw this on Facebook the other night – together with the comment:

“If Hamilton don’t want fluoride in the water, how about we replace the water”


Yes, that would be convenient, wouldn’t it. Instead of Hot and Cold taps, why not Red and White?

However, there is an element of truth in the joke. To some extent, the Waikato water is the problem, rather than fluoride added during fluoridation. Anti-fluoridationists are concentrating on the “evils” of the fluoridation agent, fluorosilicic acid, without realising that the source for our water supply in Hamilton introduces more contamination than the fluoridation chemicals.

Have a look at this graphic showing the levels of arsenic (As) in the Waikato River. Through almost the entire length of the river As levels are several times higher than the recommended maximum concentration for human consumption which is 0.01 parts per million (ppm).

The source water for the Hamilton water treatment plant is 2 or 3 times that recommended maximum As concentration.

Fortunately the treatment process remove about 80% of the As.

Let’s compare that with the contamination introduced by fluoridation chemicals.

A typical concentration of As in fluorosilicic acid is 2 ppm (see Fluoridation – are we dumping toxic metals into our water supplies?  and Water treatment chemicals – why pick on fluoride?). There is a large amount of dilution of the fluorosilicic acid when added to water at the recommended dose (0.7 – 1.0 ppm). The final concentration in our drinking water is 0.0001 ppm As. Several orders of magnitude lower than the maximum recommended concentration for human consumption.

In reality, even after removal of 80% of As from the source water the major contribution to any As contamination in Hamilton’s public water supply is the Waikato River itself – not the fluoridation chemicals. By several orders of magnitude.

  Original Arsenic (ppm As) Dilution Contribution to finished water (ppm)
Recommended maximum As (ppm)     0.01
Waikato River water ~0.025 None ~0.005
Fluorosilicic acid 2* ~200,000 ~0.0001

* see Fluoridation – are we dumping toxic metals into our water supplies?  and Water treatment chemicals – why pick on fluoride?

Haven’t the Hamilton anti-fluoridation campaigners got their priorities wrong when they complain about contamination of the fluoridation chemicals used?

See also:

Making sense of fluoride Facebook page
Other Fluoridation articles

Water treatment chemicals – why pick on fluoride?

Almost every person arguing against fluoridation makes the claim that the fluoridation chemicals used are toxic and corrosive. They also claim they contain toxic heavy metals which contaminate our drinking water.

But this is simply fear mongering – relying on chemophobia, because most concentrated chemicals are toxic and often corrosive. And such claims could also be made of the other chemicals used in drinking water treatment. But the anti-fluoridation activists don’t – why pick on fluoride?

Actually, the fluoridation chemicals used are not the main source of possible toxic contamination of our water supply – yet these other chemicals are ignored by anti-fluoridationists. When we consider fluoridation in the context of the water treatment process and analytical data for the chemicals used we find the anti-fluoridation arguments baseless.

The water treatment process

The figure below provides a context for considering the chemicals used in public drinking water treatment and the stages where they are added. It’s a diagrammatic outline of Hamilton City’s water treatment plant (it still include fluoride addition – I guess they are holding off changing the diagram until after the referendum). You can see further details in  A Guide to Hamilton’s Water Supply : River to the Tap.


This is only a typical example. Different treatment plants use different chemicals depending on the plant size, the water source and the availability and cost of chemicals. I consider just a few  representative chemicals below with information on their safety, corrosive nature and chemical contaminants.

Information sources used

The safety information is from safety data sheets produced by the manufacturer or seller. Many of these are in the Orica Chemicals SDS database.

Information on contaminating heavy elements and other contaminants is from Brown et al. (2004). Trace contaminants in water treatment chemicals: sources and fate, American Water Works Association, Journal. 96: 12, 111-125.

Extra information on contaminants in fluoridation chemicals is from the NSF Fact Sheet on Fluoridation Products (2013) and the  NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997.

miscellaneous chemicals

A number of chemicals like lime, soda ash, carbon dioxide, potassium permanganate and other acids and alkalis are used, sometimes or commonly. This could be for initial treatment to remove biological matter and in pH control and sedimentation. Adjustment of pH is also necessary to prevent corrosion of pipes.

Coagulation and sedimentation

Aluminium sulphate or alum, is a common coagulant.  Its Safety Data sheet does not classify it as dangerous for transport but does classify it as hazardous – subclasses 6.1 – 9.3.

Under disposal methods it says:  “Refer to local government authority for disposal recommendations. Dispose of contents/container in accordance with local/regional/national/international regulations.”

Possible contaminants (Brown, Cornwall & McPhee, 2004): Coagulant chemicals are the main source of trace metal contamination in water treatment.” However, these together with contaminant trace metals in the source water are generally transferred to the residue stream during sedimentation and filtering so there is little transfer to the finished water.

Soda ash is used for pH control. Its Safety sheet does not classify it as dangerous for transport but does classify it as hazardous – subclasses 6.1 – 6.4.

Under disposal methods it says:  Refer to local government authority for disposal recommendations. Dispose of material through a licensed waste contractor.”


Chlorine is commonly used. Its Safety data Sheet classifies it as a class S7 dangerous poison which “must be stored, maintained and used in accordance with the relevant regulations.”

Under disposal methods it says: “Refer to Waste Management Authority. Dispose of material through a licensed waste contractor. Contact supplier for advice.”

Possible contaminants (Brown, Cornwall & McPhee, 2004)Carbon tetrachloride (used to clean storage containers)


Fluorosilicic acid is the most common fluoridating chemical. Its Safety data sheet describes it as a class S7 dangerous poison.

Under disposal methods it says: “Refer to Waste Management Authority. Dispose of  material through a licensed waste contractor. Decontamination and destruction of containers should be considered.”

Possible contaminants (Brown, Cornwall & McPhee, 2004): Arsenic was the only trace metal contaminant found above detection levels in just a few samples, and then in small amounts.

This year’s NSF Fact sheet on fluoridation  also confirmed this picture. saying:

“In summary, the majority of fluoridation products as a class, based on NSF test results, do not contribute measurable amounts of arsenic, lead, other heavy metals, radionuclides, to the drinking water.”

(NSF International is a global independent public health and environmental organization that provides standards development, product certification, testing, auditing, education and risk management services for public health and the environment.)

The  NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997 says:

“Commercially available hydrofluorosilicic acid, sodium fluoride and sodium silicofluoride are not known to contribute significant quantities of contaminants that adversely affect the potability of drinking water.”

I discussed the question of the level of toxic metal contamination in fluorosilicic acid in my article Fluoridation – are we dumping toxic metals into our water supplies? This mentions the requirement of suppliers to provide certificates of analysis to make sure their product is suitable for water treatment. A number of certificates of analysis for fluorosilicic acid are available on line which confirm the very low levels of contaminant heavy metals. For typical fluorosilicic acid certificates see Incitec 09, Incitec 08 and Hamilton City.

The table below also shows typical analytical results for fluorosilicic acid.

General conclusions

According to Brown, Cornwall & McPhee, 2004:

“Except for occasional contamination from bromate in sodium hypochlorite and carbon tetrachloride in chlorine., drinking water treatment chemicals were not typically shown to be significant sources of most contaminants of regulatory concern (including lead, copper, arsenic, and other trace metals) in finished water. This was becausc of the low occurrence of contaminants in drinking water treatment chemicals and the partitioning of most contaminants into the residuals streams when they were present in raw water or treatment chemicals.”

The recovery of sediment and sludge after coagulant treatment removes most of the toxic contaminants coming from the source water and the treatment chemicals (mainly the coagulant). No significant contamination comes from the chlorine or fluoridation chemicals added towards the end of the treatment. The table below confirms this.

The real amounts of contaminant toxic metals in fluorsilicic acid are far lower than the amounts allowed by the water treatment standards.  The regulated impurity levels are calculated from the maximum acceptable values of an impurity (taken from the Drinking Water Standards for New Zealand 1995) and the dilution when the material is added to drinking water to achieve a concentration of 0.7 – 1.0 ppm F. It incorporates a safety factor of 10. The data for the fluorosilicic acid is from my research but confirms figures in certificates of analysis. And the last column shows that there is no detectable contamination of toxic heavy metals in the final drinking water

Final drinking water quality

Toxic Element Impurity limits FSA Drinking water
As (ppm) 132 2 <0.002
Cd (ppm) 40 <1 <0.001
Cr (ppm) 660 5 <0.001
Hg (ppm) 26 < 0.1 <0.001
Ni (ppm) 264 < 1 <0.001
Pb (ppm) 132 0.3 <0.001
Cu (ppm)   < 0.2 <0.013
Zn (ppm)   2.1 <0.013

Impurity limits – calculated from maximum acceptable values in drinking water and a safety factor of 10. See NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997.
FSA – typical analytical data for fluorosilicic acid used in fluoridating New Zealand water supplies.
Drinking water – actual levels of toxic elements in your drinking water (Wellington region) – all below the limit of detection of the standard analytical procedure.

The “proof of the pudding is in the drinking” – one could say. The antifluoridation activists have been simply scare mongering with their claims that fluoridation amounts to putting toxic elements into our drinking water. The fluoridation chemicals are not even the main possible source of such contaminants.

See also
Fluoride in our water facebook page
Debunking the anti-fluoridation myths
From Australia – debunking anti-fluoridation arguments

For other articles on fluoridation see Fluoridation page.

Is fluoridated water a medicine?

One of the predictable claims made by anti-fluoridationists is that fluoridated water is a medicine and therefore should not be imposed on the public.

It’s all semantics, of course, but some anti-fluoridationist get pretty dogmatic about it. So the people who run the Fluoride in Water* Facebook page decided to check it out with Medsafe – the New Zealand Medicines and Medical Devices Safety Authority.


Here’s the guts of the reply they got from the Medsafe Pharmacovigilance Team:

“A medicine is defined in S3 of the Medicines Act as:

a substance or article, other than a medical device, that is manufactured, imported, sold, or supplied wholly or principally for

a) administering to one or more human beings for a therapeutic purpose

b) use as an ingredient in the preparation of any substance or article that is to be administered to one or more human beings for a therapeutic purpose,

  • where it is so used- in a pharmacy or a hospital; or
  • by a practitioner, or registered midwife or designated prescriber, or in accordance with a standing order; or
  • in the course of any business that consists of or includes the retail sale, or supply in circumstances corresponding to retail sale, of herbal remedies;

c) use as a pregnancy test.

S4 defines the term therapeutic purpose as:

  • treating or preventing disease
  • diagnosing disease or ascertaining the existence, degree, or extent of a physiological condition
  • and several other non-pertinent activities.

“However, Medsafe has never considered the fluoridation of water to lead to the creation of a medicine. Fluoride is found naturally in water at varying concentrations and water is not supplied for a therapeutic purpose. We consider that the principal use of water and foodstuffs (which contain minerals or fluoride) is dietary and not therapeutic. We therefore do not consider the addition of substances such as chlorine or fluoride, or alum to water to be under the remit of the Medicines Act but rather under the control of other public health and water quality legislation. A similar argument can be used in relation to quinine. While quinine is a medicinal substance, the quinine contained in a gin and tonic, no matter how therapeutic we might think consuming one may be, does not make tonic water (or gin) a medicine. This pragmatic approach to the legislation is clearly what was intended by parliament. Too rigid an interpretation quickly makes everything a potential medicine. After all we drink water to prevent dehydration which is a symptom of a disease state. This kind of over-interpretation of the wording of the legislation is not, and has never been the intention of parliament.

“Finally while we must accept that fluoride in certain concentrations and formulations is scheduled as a medicine in several schedules within the Medicines Act, the concentrations of fluoride in drinking water are well below the threshold for consideration as a medicine and so would be considered to fall within the controls of other legislation, such as water quality control etc. Fluoride is also an element and it is naturally found in a great many places, the presence of fluoride, or any other element or mineral in an item does not make the item a medicine. After all, lithium can be used as a medicine, but its presence in a lithium battery, or a paint, does not make that product a medicine.”

via Why fluoride water is not classed as a medicine under the Medicines Act – Medsafe.

* Follow that Facebook page if fluoridation interests you – it’s one of the few trying to give good scientific information and counter the misinformation that seems to be common on social communication sites like Facebook and Twitter.

For further articles on fluoridation look at the links on the Fluoridation page.
See also: Fluoridation

Fluoridation – are we dumping toxic metals into our water supplies?

Opponents of fluoridation usually use a raft of arguments – this sometimes make discussions difficult because it leads to Gish Galloping which prevents proper discussion of any one issue. So in this blog post I want to restrict myself to just one of the anti-fluoridationist claims – one I have always been cynical about.

This is the assertion that the fluorides used for fluoridation of public water supplies is contaminated with toxic elements – heavy metals and radioactive elements.

Problem is – about 10 years ago I was using a commercial batch of hydrofluorosilicic acid – FSA (the chemical used for fluoridating Hamilton’s water supply) for our research. We analysed our material – and the results show definitely that it was not contaminated with toxic elements. The amounts present were extremely low

As (ppm) Cd (ppm) Cr (ppm) Hg (ppm) Ni (ppm) Pb (ppm) Cu (ppm) Zn (ppm)
2 <1 5 < 0.1 < 1 0.3 < 0.2 2.1

So what’s going on? Is my data (admittedly anecdotal evidence for one batch) an outlier? Or is somebody telling porkies?

The claim

Here I quote from the 7 objections to fluoridation listed by the Fluoride Action Network – FANNZ (the activist group leading the current activist mobilisation against fluoridation). See Our objections to fluoridation.

6. Fluoride used in fluoridation is contaminated with heavy metals including lead

Fluoridation was originally a corporate promoted solution for the aluminium industry to sell their toxic waste product for profit. Today fluoride for drinking water comes from the chimneys of the phosphate fertilizer industry. The fluoride used is contaminated with heavy metals (including lead a known neuro toxin) and sometimes radioactive material, posing added health risks (NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997). The phosphate industry use “scrubbers” to capture fluoride gases produced in the production of commercial fertilizer. This is because if they allowed too much of it to escape into the atmosphere they would be liable for being major polluters. If the fluoride acid was placed in a barrel with holes in it, and dumped in our rivers they would face heavy fines and criminal prosecution.

However a solution has been found whereby the fluoride acid (hydrofluorosilicic acid), a classified hazardous waste, is barrelled up and sold, unrefined, to communities across the world for the purpose of adding it to public water supply to mass medicate populations to prevent tooth decay in forming teeth. Mysteriously the substance becomes safe for the environment and humans once it’s sold in this regard. Even if you don’t live in a community where fluoride is added to water, you’ll still be getting a dose of it through cereal, soda, juice, beer and any other processed food and drink manufactured with fluoridated water. If it is illegal for these corporations to dump the waste in our rivers it certainly should be illegal for them to sell fluoride for the purpose of adding it to our drinking water.

Of course, this sort of claim gets copied and pasted when activists make submissions  to local bodies on the fluoridation issues. Here’s one made to a Palmerston North hearing by “a concerned citizen and grandmother” who is “appalled at the documented adverse health effects associated with water fluoridation. . . . .  After much research on the subject” she “discovered some sobering and disturbing facts (and I emphasise that these are facts and not just my opinion).” 


Notice the claims, and the confidence with which they are made. Also notice  how a citation to NZ Water and Wastes Association Standards is used to give the claims an air of “sciency” authority.

The citation.

Unfortunately no link to the actual publication was provided by FANNZ – perhaps because it doesn’t actually say what they claim it does. I’ll give the link here – NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997.  Download the pdf and read it for your self. Check it out.

Here’s a comparision of the anti-fluoridationist claim with what the document says about the fluoridation chemicals used for public water treament in New Zealand.



The fluoride used is contaminated with heavy metals (including lead a known neuro toxin) and sometimes radioactive material, posing added health risks (NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997). Commercially available hydrofluosilicic acid, sodium fluoride and sodium silicofluoride are not known to contribute significant quantities of contaminants that adversely affect the potability of drinking water.

The claim is completely wrong and is not supported by the citation.

That is the only comment the document mnakes about actual levels of contaminants in the  commercial chemicals on the market. Why should such a publication go into further details?  The standards are aimed at protecting the health of the people. Preventing chemicals from being used if they are contaminated by toxic elements, for example. It’s not their job to go into the history, manufacture and composition of commercial chemicals – only to consider these issues when they come to select material for use.

The publication describes, for example, standard for maximum levels of heavy metals in fluoridation agents:

“ Hydrofluosilicic acid shall not contain more than 0.02% w/w heavy metals expressed as lead (Pb).”

It describes standard procedures for handling the chemicals used. (Yes, many chemicals in their concentrated forms a dangerous and must be handled correctly, even though they are harmless when diluted to the concentration they are used. Just think about chlorine – really dangerous in the form purchased commercially – but no one is complaining about the levels in our water supply).

The publication describes requirements for chemical analysis of supplied materials, and the responsibility of the supplier to provide materials which comply with the standards and certificates guaranteeing compliance.

So FANZZ is being rather disingenuous using this publication to support their erroneous claim. If anything the publication shows that authorities have a regime in place to make sure the material they use is not contaminated.

What are the concentrations in our drinking water?

The Greater Wellington Region uses Hydrofluorosilicic acid (HFA) at their Gear Island treatment plant. Their web site say that “the HFA we use is tested to ensure that any other chemical elements of health significance that it contains are at safe levels in relation to the Drinking Water Standards for New Zealand.” And they provide a chemical analsis of the water supplied to their citizens. Here are some typical results:

As (ppm) Cd (ppm) Cr (ppm) Hg (ppm) Ni (ppm) Pb (ppm) Cu (ppm) Zn (ppm)
<0.002 <0.001 <0.001 <0.001 <0.001 <0.001 <0.013 <0.013

The Fluoridation Action Network (FANZZ) is simply fear mongering with this claim. They are capitalising on a naive fear of “chemicals.” They are making false claims about contamination of the fluoridating agents used. And they are using a citation dishonestly – to support a claim the publication does not support.

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