It conveys some of the points I was making in Is fluoride an essential dietary mineral? More clearly, I think.

It also provides a useful template for placing research findings, and the claims being made about them, into context. Most claims about the harmful effects of fluoride are represented by the red line. They have been found at, and are important at, higher concentration of F. Whereas the beneficial effects are displayed at lower concentration.

The CDC recommended for fluoridated water in the diagram is similar to that for New Zealand (0.7 – 1.0 ppm) (The US has a larger range to accommodate for different intakes of water in different climates)

Remember – this is purely diagrammatic – it shows the principles, not real data.

But next time yet get told by an anti-fluoridation activists how horrible fluoridation is and they make claims based on research, or refer to a scientific paper – think of this template. Ask about the concentrations involved.

See also:

Is fluoride an essential dietary mineral?
Fluoridation – are we dumping toxic metals into our water supplies?
Tactics and common arguments of the anti-fluoridationists
Hamilton City Council reverses referendum fluoridation decision
Scientists, political activism and the scientific ethos

Similar articles

Source: Dietary Minerals, Wikipedia

Anti-fluoridation activists often assure us that fluorine (F) is not an essential element. But what does that mean? Literally I guess it means that there are no identified biological pathways essential to human life involving F. So anti-fluoridation activists often claim the only safe level of flourine in the human diet is zero!

But whether an element is essential or not is often unclear or undecided. Some sources claim about 16 elements seem to be essential to maintain life. Others claim over 20 elements are essential.

Fluorine is rather debatable, as the above Periodic Table of the elements suggests. The Wikipedia entry on Dietary Minerals does say, however:

“Fluorine (as Fluoride) is not generally considered an essential mineral element because humans do not require it for growth or to sustain life. However, if one considers the prevention of dental cavities an important criterion in determining essentiality, then fluoride might well be considered an essential trace element.”

So F may well be considered an essential trace element, or a beneficial element. By the way, we should not let the fact that F is known to have harmful effects when in excess lead us to deny its beneficial effects. Probably all essential or beneficial elements and trace elements do.

Essential and beneficial elements usually display a “beneficial window” of  intake. This can be shown by a U shaped  graph when we plot the incidence of negative effects against intake (see figure below).

Source:  Howd & Fan, 2007 -  Risk Assessment for Chemicals in Drinking Water page 202.

So we expect to see that sort of relationship with F intake if the element is essential, or even just beneficial. If there are no benefits from F we would expect only an increasing incidence of negative effects when the intake increases from zero. Of course we also see that for essential or beneficial elements if we restrict our data to only high levels of intake.

Does F have benefits besides dental ones?

Do the benefits of F extend more widely than the prevention of dental cavities? I have often thought they do because F has a clear effect on the structure and solubility of hydroxyapatites – an important and major componet of bones. A small amount  of substitution of F for OH in the hydroxyapatite structure can strengthen such minerals and lower their solubility. Bioapatites are a major component of our skeletons, and play a role in many of our organs. This chemical substitution may actually have positive effects on bone health, and the properties of other bioapatites. Of course excessive substitution, or differentiation into different chemical crystalline phases, may also have negative effects when there is excessive intake.

By the way, F is not the only elements that substitutes at trace levels in bioapatites. There are many more and they can each influence the properties of the bioapatite.

Another way of looking at this is that pure chemically defined compounds rarely exist in the real world. Other minor elements are often incorporated into the crystal structure, or be present in a closely associated crystal phase.  These “impurities” or substituted elements usually impart features to the natural material which are greater or lesser than, or perhaps not even seen, in the pure compound. These features can be important to the biological role of crystals in nature and life.

Because biological systems are always exposed to a whole range of chemical elements at varying concentrations there will be no such thing as zero F intake. Nobody’s body is “fluoride free.”

Beneficial effects of F on human bones?

I recently checked out a paper which shows beneficial effects  of F on human bones along the lines I have suggested.  The paper is Yiming Li et al., (2001): Effect of Long-Term Exposure to Fluoride in Drinking Water on Risks of Bone Fractures. The authors are a group of researchers from the US and China. You can download the PDF here and check out methodology and other details.

Here’s one of the figures from their paper summarising the relationship of overall bone fractures to F content of the water supply used.

Effectively, this displays the U-shaped curve mentioned for essential elements in Risk Assessment for Chemicals in Drinking Water.

Or, perhaps more importantly – statistically significant increases in numbers of bone fractures occur at both low levels of fluoride in drinking water (<0.3 ppm) and at high levels (>4 ppm).

The authors express it this way:

“The data appear to suggest that there may be a “beneficial window” of fluoride intake for bone health, because an increased risk of overall bone fractures was detected in both the populations with deficient and excessive fluoride in drinking water.”

Not surprisingly this window corresponds approximately to current New Zealand advice for oral health  - concentrations of fluoride in the water supply in the range 0.7 to 1.0 ppm are beneficial.

So perhaps we should consider F as an essential, or at least, beneficial trace element as Wikipedia suggests. And perhaps health authorities in New Zealand should include bone health, together with oral health, in their advice on fluoridation.

The quality of research studies is critical

Other groups have produced similar conclusions to that of Yiming Li et al. - particularly that the incidence of bone fractures are reduced by fluoride doses in the beneficial range of F intake. But, these sort of investigations are very complex so it’s possible to find other studies which don’t show this result, or show only the effects of high fluoride intake. This raises the question of the quality of such investigations and the need for readers and reviewers to be particularly informed about such issues.

Many of these sorts of studies produce results of questionable quality because they ignore the role of other factors besides F in the water supply. For example, in many developed countries, and many developing ones, dietary intake of fluoride also comes from toothpaste, mouthrinses and dietary supplements. The high mobility of modern populations also makes it difficult to relate clinical effects to simple factors in the current environment of the individuals. It’s no wonder that attempts to relate health effects to fluoride concentrations in the public water supply produces controversial findings.

Mind you, that’s a great gift to the unscrupulous cherry-picking, uncritical reviewer with an ideological or activist axe to grind. If you are selecting studies to support a preconceived viewpoint the influence of other factors is not important – you just choose what suits your argument and ignore the quality. But if you are trying to establish a reliable picture of what is actually happening, as we hope our health professionals and scientists are, it’s important to consider the quality, and reliability, of each study.

My impression is that this particular study is considered of high quality because it used populations with a defined history of fluoride exposure. The authors say:

“In contrast to the U.S. population, residents of rural China rarely change residences, and most have been using the same water supply throughout their life. Because of its unique environmental and cultural conditions, such as virtually no residential mobility and a relatively consistent lifestyle, rural China has been considered a perfect “living laboratory” for studying the relationship between various factors and diseases. The survey results of our study sites and data from individual subjects show that fluoride exposure in rural Chinese communities is still limited to water and diet.”

And in their methodology:

“The residency of each subject was determined by the following three measures: (1) objective assessment by checking the Family Registry Book, an official document issued by the government; (2) a subject survey questionnaire; and (3) confirmation by village officials who were familiar with the subject.”

This sort of reliability of information is just not available for modern populations in most countries, making these sort of studies unreliable.

The lesson here is that there must employ intelligent and expert consideration when reading or reviewing research in this sort of area. People consulting such studies and reviews should also be aware of the dangers. When public debates, like that over fluoridation, occur we need to be aware of the way activists may draw unreliable conclusions from the literature and promote those unreliable conclusions to the public.

As an aside – this study also considered possible effects of factors like gender, smoking and alcohol – not surprisingly bone fracture were higher for men, and for those consuming alcohol!

Conclusion

So, is fluoride an essential element? I don’t know and I am hardly the person to decide. But clearly it is possible to argue the case that it may be, or that it is at least a beneficial element, provided dietary intake is neither too low or too high. It’s a complex area – just beware of activists with an axe to grind and a simple picture to support their claims.

See also:
Fluoridation – are we dumping toxic metals into our water supplies?
Tactics and common arguments of the anti-fluoridationists
Hamilton City Council reverses referendum fluoridation decision
Scientists, political activism and the scientific ethos

Similar articles

Disaffection with the Hamilton City Council decision to stop fluoridation has resulted in an attempt by at least one councillor to get the decision reversed and submitted to a referendum. The Waikato Times is reporting:

The notice of motion from Mr Wilson being circulated today among city councillors today would force the council to debate when it meets in three weeks whether it should hold a referendum.

Mr Wilson said the controversial decision had been hijacked by the anti-fluoride lobby and was not what the majority of Hamiltonians wanted.

“The anti-fluoride position are mostly well-meaning individuals that have misinterpreted the science. And then there’s a group of nutters who are convinced this is mass-medication. There is considerable good science that shows fluoridation is a good base for public health. I believe the majority of people in Hamilton want fluoridation, and they should have the final say.”

Seems to me this would be the best outcome. Hamiltonians have shown in the previous referendum and recent polls they support fluoridation and there has been a lot of criticism of the Council’s recent decision.

Mind you, the anti-fluoridationists are not happy:

the co-ordinator of Fluoride Free Hamilton, Pat McNair, said a referendum was not necessary.

“A tribunal is a robust process where reasoned evidence from both sides can be given. A referendum is just peoples’ opinion in the street.

“The others [Councillors who voted against water Fluoridation] in their summary gave very good reasons why a referendum would not work.”

Ms McNair said she would only accept a referendum if lobbies from both sides of the argument had equal amount of money to campaign with, as education costs “hundreds of thousands of dollars.”

Ms McNair really seems to not like a democratic and full discussion. She preferred a almost behind-doors tribunal dominated by 90% anti-fluoridation submission when the city itself had voted 70% support for fluoridation. The real problem is not money to campaign with – but the presence of activist groups to do the campaigning. She had everything her own way with the tribunal, no wonder she doesn’t want a referendum and the associated public discussion

A referendum will give opportunities for supporters of fluoridation to organise and get their case across. Hopefully they will do so. If not they will only have themselves to blame.

See  Hamilton City Council | Referendum On Fluoride |… | Stuff.co.nz.

The Hamilton City council had been exposed to large numbers of submissions from anti-fluoridation activists. Most of them misrepresented the science and gave misleading, often incorrect, information. Scientists could have corrected these mistakes and distortions, but the job was left to a few representatives of the District Health Board and the Ministry of Health.

Many scientist think, as do others in the community, that they must play a greater role countering distorted information and pseudo-science. But the scientific ethos of objectivity, evidence-based debate and peer review conflicts with the political nature of such activism.

It’s a problem that scientists, especially younger scientists, will have to face increasingly in the future. Quite a few of us have solved the dilemma for ourselves by blogging – a sort of half way point between ivory tower science and political activism.

But here is something to think about. Climatologist James Hansen has thought about this issue throughout his life. Sometimes he has opted for pure science, these days he is opting for pure activism. Here’s an excellent video of one of his talks from February 2012 explaining his motivations and history on this issue. It’s also a simple and clear explanation of the climate change problems we are facing now and in the future.

James Hansen: Why I must speak out about climate change 

Hansen has also written about these issues in his book   Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity. Have a look at  Global climate – and your grandchildren for my review of the book.

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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

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 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:

“2.3.3.3 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:

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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This must be what it’s like for some climate scientists at the moment.

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In essence this is the same as the “sciency” sounding tactics of the climate change and evolution science denial movements. These tactics of the anti-fluoridationists were analysed by Jason M Armfield in his 2007 paper When public action undermines public health: a critical examination of  antifluoridationist literature. Tactics like:

• Selective reporting of studies and results,
• Downplaying or ignoring the evidence,
• Ignoring ecological factors in comparing communities,
• Fear mongering,
• Misrepresentation of evidence,
• Using half-truths and “The Big Lie,”
• Innuendo,
• Follow the leader arguments.

In short – bamboozling with science.

The paper provides a clear and well documented description of the anti-fluoridationist tactics. It does briefly give examples and citations to show how the science gets distorted, although detailed discussion of the science is not the main purpose of the paper. It’s a useful resource for anyone trying to come to grips with the “Gish galloping” claims made by these activists.

One of the tables in the paper provides a handy list of common arguments used together with brief rejoinders. It’s a handy summary and I have reproduced the content below – the fluoridationist claim, followed by the real situation:

Water fluoridation confers no oral health benefit:

Numerous systematic literature reviews from a number of countries have found water fluoridation to provide a significant caries preventive effect.

Water fluoridation causes hip fractures, cancers, Alzheimer’s, reduced intelligence in children, etc.:

Research finding associations between water fluoridation and various diseases offer no proof, as causality cannot be established in these studies. Water fluoridation opponents handpick studies and may misrepresent the results so as to support their views. Large-scale systematic reviews have not confirmed any associations between water fluoridation and the large list of diseases linked to it by opponents of water fluoridation.

Fluoride is a toxic poison:

Fluorine is a naturally occurring element that, like many other natural substances, can be toxic if consumed in excess. Water fluoridation ensures ingestion of fluoride well below any toxic level, both for adults and children. Fluoride is used in rat poison and other dangerous substances. It is dose that determines the level of toxicity. Many essential and commonly occurring elements form poisonous or toxic substances.

Numerous other countries have rejected water fluoridation:

Some other countries have elected not to introduce water fluoridation because they prefer, or already have, other approaches to improving dental health. Nonetheless, many countries do have water fluoridation and benefits are conferred to all people, including those at high risk who may not effectively use individual fluoride exposures.

Water fluoridation is supported only by ‘shoddy’ science:

Decades of research and hundreds of scientific articles published in peer-reviewed journals support water fluoridation. This research is so convincing that almost all major dental and health authorities support it.

There should be a public plebiscite. It is undemocratic to have water fluoridation forced upon us:

In almost all democratic systems representatives of a population are elected to make decisions on behalf of the population. Plebiscites or public referendums are not required to pass legislation that is compatible with the constitution or charter under which the country operates. Water fluoridation fits within a government’s duty of care to the country’s citizens.

Tooth decay has declined in countries with and those without water fluoridation. Water fluoridation makes no difference:

Declines in tooth decay have occurred as a result of changing exposures to fluoride and dietary changes. Regardless, water fluoridation reduces tooth decay above and beyond these other effects. Ecological comparisons of some countries with others offer no support for or against water fluoridation as many other factors may account for differences in disease experience from one country to the next. Water fluoridation does make a difference.

Most people do not want water fluoridation:

Independent research in most places where water fluoridation is being considered shows that people support water fluoridation. Generally, the more knowledge people have the more likely they are to support it.

Water fluoridation is costly and not economically viable:

Research has previously found water fluoridation to be cost-effective. Newer technologies have made water fluoridation cost-effective for increasingly smaller populations. In addition to being cost-effective, it is also necessary to keep in mind the reduction in dental disease and therefore the pain and suffering reduced as a result of water fluoridation.

Water fluoridation infringes freedom of choice and individual rights and is unconstitutional:

Adding fluoride to water is just one of many instances where a chemical or nutrient is added to a food or beverage for public health benefits. It already occurs in water with the addition of chlorine, which aids greatly in eliminating water borne disease, as well as in several foodstuffs. Water fluoridation sets no precedent.

Water fluoridation is being pushed on us as a result of ‘big business’ interests:

The scientists researching the effectiveness of water fluoridation as well as health officials and dentists do not receive money from sugar, aluminium or any other companies for their research or opinions.

There is more caries in fluoridated X than in non-fluoridated Y. This proves water fluoridation does not work:

Ecological comparisons involving the arbitrary selection of fluoridated and non-fluoridated communities or areas do not provide credible evidence of the effectiveness or otherwise of water fluoridation as any differences may be the result of other factors which are linked to tooth decay but differ across the areas. Scientific research has found water fluoridation to be effective.

We should wait until water fluoridation is proved to be safe:

Water fluoridation has been implemented in some places for more than half a century – long enough that any dangers would be apparent if they existed. The weight of evidence strongly indicates that water fluoridation is safe.

I think this list provides a good starting point for sensible discussion.

Thanks to Jason M Armfield (2007): When public action undermines public health: a critical examination of  antifluoridationist literature. Australia and New Zealand Health Policy 2007, 4:25

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(Note: If you are sufficiently interested that Waikato Times article has an attached poll where you can express your view. Early votes ran against the council decision, but subsequently the anti-fluoridators seem to have organised to fix that).

Yes, I know. I should have paid attention. But I am probably pretty typical in my apathy about local body politics.

I did know something was afoot – after all an old friend of mine had told me months ago he was part of a campaign to stop fluoridation. But as we had been through all that 7 years ago I thought the format would be the same.

In 2006 a citizen referendum decisively supported continuation of fluoridation in Hamilton’s water supply. That referendum was preceded by much public debate in which supporters and opponents actively presented their arguments.

So, I think I (and other Hamiltonians) can be excused for thinking we were running up to similar referendum held alongside the next local body elections. But we were mistaken. The Waikato Times tells us how it was done:

“The decision, just reached after less than an hours’ debate, followed a lengthy tribunal which heard the weight of public submissions, many from outside the city, argue for the removal of hydrofluorosilicic acid from the water supply.”

Well, I guess that is the price of apathy. But, given the history, I can’t help feeling rather duped. In my mind there are two issues:

Democracy

This time the issue seems to have taken place behind closed doors – at least figuratively. Apparently submissions are on the City Council web site (and I will certainly be perusing those as the Times article implies they were one-sided). But the public discussion has been pretty minimal – it certainly didn’t register with me. And as a chemist, with some background in researching carbonate apatites (and the role of fluoride in them) I should normally have noticed.

The vote seems rather funny – 7 to 1 to stop fluoridation. With five councillors withdrawing from the vote – 3 councillors “removed themselves after declaring a conflict with their district health board roles.” Bloody hell, one might have expected these three councillors to have a better understanding than the others.

And the question of understanding also raises issues. How informed were the 7 councillors who voted to stop fluoridation? How representative were the submissions they presumably took note of? And, considering the importance of health issues like this, shouldn’t they have done more to get advice from reliable professionals?

In fact, I really wonder if a local council is the right sort of body to consider such important health issues.

Science

In public discussion of these issues the science is often problematic. Both sides on the fluoridation issue will present sciency sounding arguments and these are often difficult for the layperson to consider objectively. Just like the climate change issue. However, given the importance of the fluoridation issue and the fact that a representative body is charged with making the decision it is important for public discussion to at least have the opportunity to be informed scientifically.

In this case I don’t believe the public was adequately informed – and I suspect that neither were the council members. (I really must check out the submissions they received).

The other aspect of these sort of public issues is the way that scientific knowledge gets used. Often pseudo scientific arguments are used. Strongly motivated people will cherry pick, search for information, misrepresent information, to support their firmly held views. Yes, I know – this is only human – we are all prone to confirmation bias. But that is why it is important to make sure there is adequate representation of views. And to make sure professional experts make submissions and give their comments on the submissions of others.

Finally, this is a health issue – and like most health issues it is the most vulnerable who have the most at stake, but usually have the least opportunity to take part in decisions. It will be the children of the economically most disadvantaged families who suffer the decline in dental health. Not only because of weakened dental enamel but also because they are also the people less likely to be receiving adequate dental care as they grow.

See also:

Water Fluoridation – the emotional tail wags the dog in Hamilton
Waikato DHB ‘very disappointed’ with fluoride decision

“Cli-fi” is that genre of fictional writing about climate change. More a sub genre of science fiction than erotica!

The comments on this Guardian article are interesting – they mostly suggest titles of books the commenter considers part of this new genre. But also interesting was that several commenters mentioned fellow SciBlogger Gareth Renowden’s book The Aviator. My impression was that it was actually the most mentioned example of ‘cli-fi’ so it’s obviously developing  a readership. Comments about the book were favourable – as was my review (see Kiwi science fiction with a message).

Among the other mentions was the series Science in the City by Kim Stanley Robinson. These are  Forty Signs of Rain, Fifty Degrees Below  and Sixty Days and Counting.
Each of these is rather long – but I have listened to the audiobook versions and actually quite enjoying them. They won’t be to everyone’s taste – for example, some of the characters indulge in a lot of introspection. But this does mean the books cover personal and relationship issues, as well as reflections on the nature of science and politics. And there is some action – even spies. However, the books are realistic science fiction, set in the near future, within the political and science bureaucracies of Washington, DC. The natural calamities are credible and realistic. As are discussion of projects for slowing climate change.

An interesting series of books.

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Image credit: Edublogs Teacher Challenges

There are now over 280 blogs on the list, although I am weeding out those which are no longer active or have removed public access to sitemeters. Let me know if I weed out yours by mistake, or get your stats wrong. Often bloggers will unintentionally delete the site meters when they refurbish their blog.

Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats. There are also a few bloggers who have sent me their links but have not yet set up public access on their sitemeters.

Here are the rankings of New Zealand blogs with publicly available statistics for May 2013. Ranking is by visit numbers.

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters.

I have listed the blogs in the table below, together with monthly visits and page view numbers for May, 2013.

Meanwhile I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

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