Tag Archives: contamination

Fluoridation contribution to heavy metals in drinking water is too low to measure

Anti-fluoride activists claims of fluoridation chemicals being laced with toxic metals just do not stand up to scrutiny

Anti-fluoridation activists claim fluoridation adds toxic heavy metals to drinking water because the fluoridation chemicals are “waste products” from industry (the phosphate fertiliser industry). Despite the fact that published research shows this not true.

The activists rarely give evidence for their claims but when they do they cite chemical data from certificates of compliance supplied to local bodies by the fluoridation chemical providers. But these activists simply have no concept of what these figures mean and always ignore the huge dilution involved in water treatment.

Example of continually tweeted scaremongering misinformation from the Fluoride Action Network’s press officer.

Anti-fluoride people particularly go on about arsenic yet a 2015 Canadian study showed that the difference in arsenic levels from unfluoridated and fluoridated water treatment plants was infinitesimal. That study is:

Peterson, E., Shapiro, H., Li, Y., Minnery, J. G., & Copes, R. (2015). Arsenic from community water fluoridation: quantifying the effect. Journal of Water and Health.

The data shows that even after treatment the concentration of arsenic due to natural sources is about 0.44 ppb. Fluoridation added a mere 0.07 ppb to this! (ppb = parts per billion = micrograms/litre = μg/L).

See Another defeat for anti-fluoridation claims about arsenic for a discussion of this paper.

The authors point out that all the drinking water systems in their study were compliant with the Canadian drinking water guideline for arsenic of 10 μg/L (10 ppb [parts per billion] – the same as in New Zealand) and the estimated amount attributable to fluoridation from this study is less than 1% of this guideline. Their results were also consistent with other published estimates of the likely contribution of fluoridation chemicals to arsenic in drinking water.

The fluoridation chemicals used in New Zealand have lower levels of impurities than those used in North America so the resulting contamination of drinking water is even lower than in Canada.

Here I look at the heavy metals contaminants in our drinking water and the effect of fluoridation on those levels

What are the concentrations of contaminants in our tap water?

They are very low – in fact, they are regulated to be very low. The regulations set maximum allowable levels (MAV) and providers must keep their contaminant below these MAV levels.

The figure below uses data taken from reports for the Hamilton City Council Water Supply Annual Compliance Report 2018/2019. I have converted the data from units of g/m3 to parts per billion – ppb. I have used data from  a certificate of compliance for the hydrofluorosilicic acid (HFA) supplied to the Hamilton City Council in 2015 (referred to in my article Chemophobic scaremongering: Much ado about absolutely nothing)

I have made this figure tall in an attempt to show the calculated contribution of contaminants concentrations from the fluoride treatment (red) alongside the actual measured levels in the tap water (green). The Y-axis is different for Barium and Aluminium because the concentrations are much higher. Click on the image to see a larger version of the figure

Here are some relevant points about this data:

1: Lead is not included because the amount is below the detection limit. The measured levels of the other contaminants of interest (green) are very low – well below the MAV values.

Waikato River water contains relatively high levels of arsenic – higher than MAV recommendations. But water treatment reduces the levels to well below the MAV level (and in some samples the levels are below the detection limit).

2: The calculated levels for contaminants due to added fluoridation chemicals (HFA – hydrofluorosilicic acid) are extremely low. In fact, in all cases, they are well below the levels that could be detected by the analytical methods used – in most cases far less than 1% of the detectable levels.

This means that the final concentration in drinking water of heavy metals added with the fluoridation chemicals is far too low to even be detected by the sensitive chemical analytical methods used. It is simply misleading for anti-fluoride activists to rave on about the contaminant levels in the concentrated chemicals without taking into account the huge dilution involved.

3: The figure below illustrates that the fluoridation treatment makes only a minuscule (undetectable) contribution of contaminant elements to the tap water.  Well under 1% of the contaminant contribution coming from the source water itself.


Fluoridation chemicals add such a minuscule amount of heavy metals to drinking water that their contribution cannot be detected. The amounts are below the detection limit of the analytical methods used.

The claims of anti-fluoride activists are emotional rather than factual. It is meaningless to publish images of compliance certificates. When they cite chemical data for the fluoridation chemicals used they simply have no concept of what the figures mean and completely ignore the high dilution factor involved in treating drinking water.

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Chemophobic scaremongering: Much ado about absolutely nothing


Sometimes anti-fluoride propagandists end up shooting themselves in the foot. This always seems to happen when they produce “evidence’ that fluoridating chemicals are loaded with toxic heavy metals.

It feels like shooting fish in a barrel to debunk their use of analytical figures because the data they produce always shows them to be completely wrong. I wrote about this before in Fluoridation: emotionally misrepresenting contamination. So, I am effectively repeating myself by discussing the meme image below that Fluoride Free NZ is currently circulating in social media.

Hill lab

Still, this time, I will show how insignificant these analytical figures by comparing the calculated final concentrations in tap water – due to addition of the chemical – with measured concentrations for these contaminants in Hamilton tap water.

Added contaminants as percentage of MAVs

But first – what contribution would this sample of fluorosilicic acid make to the contaminant levels in Hamilton’s tap water – and how do these levels compare with the maximum acceptable values (MAVs) defined in New Zealand’s Drinking Water Standards? The values for the MAVs are published in:

Ministry of Health. (2008). Drinking-water Standards for New Zealand 2005 ( Revised 2008 ) (Vol. 2005). Wellington.

In this table, the “Tap water (mg/L)” data are the calculated final concentrations after addition of the fluoridating agent in the meme. The “%age of MAV” data are these values expressed as a percentage of the maximum acceptable values (MAVs) for the contaminants.

Impurity MAV (mg/L) Tap water calculated (mg/L) %age of MAV
Aluminium 0.1 8.69E-05 0.0869
Antimony 0.02 < 3.56E-07 <0.0018
Arsenic 0.01 1.26E-05 0.1264
Barium 0.7 4.27E-06 0.0006
Cadmium 0.004 2.37E-07 0.0059
Chromium 0.05 4.74E-06 0.0095
Copper 1 1.19E-06 0.0001
Iron 0.2 1.62E-04 0.0810
Lead 0.01 2.37E-07 0.0024
Manganese 0.04 3.56E-06 0.0089
Mercury 0.007 < 1.98E-07 <0.0028
Molybdenum 0.07 < 3.56E-07 <0.0005
Nickel 0.08 3.95E-06 0.0049
Selenium 0.01 < 1.98E-07 <0.0020
Uranium 0.02 2.05E-06 0.0103

Sorry, I have had to use scientific formating for some numbers because the final calculated concentrations in tap water are so low. On average, the calculated concentration  of these contaminants due to the fluoridating agent is about 0.02% of the MAV.  The largest relative contribution is for arsenic – just over 0.1%.

Regulations require that the contribution of contaminants from fluoridating agents should always be less than 10% of the MAV . The actual level of contaminants in this particular sample is well below those regulated maxima.

The Fluoride Free NZ meme is just promoting naive chemophobic scaremongering about absolutely nothing. These activists just haven’t bothered calculating what the analytical data means for the final concentrations in tap water. Or even bothered comparing the data with the regulated maximum amounts allowed for fluoridating chemicals. These values are available in Standard for the Supply of Fluoride for Use in Water Treatment.

Added contaminants as a percentage of concentrations in inlet water and treated water.

Let’s now compare the estimated contribution from contaminants in this sample of fluorosilicic acid to the levels of the very same contaminants in the Hamilton water. I have taken data from this document issued by the Hamilton City Council:

Waikato River and Treated Drinking Water Comprehensive Analysis Report 2013/14

The next table is for samples taken on 18th July 2013 at the intake to the treatment plant (that is the source water before treatment). The “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity naturally present in the source water.

Impurity Intake (mg/L) Added FSA%
Aluminium 1.68E-01 0.05
Antimony 8.50E-04 <0.04
Arsenic 1.96E-02 0.06
Barium 1.88E-02 0.02
Berylium <1.10E-04 0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper <5.30E-04 0.22
Iron 2.94E-01 0.06
Lead 1.18E-04 0.20
Manganese 2.15E-02 0.02
Mercury <8.00E-05 <0.25
Molybdenum 3.80E-04 <0.09
Nickel <5.30E-04 0.75
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 8.13E-01 0.00

Now, a similar calculation and comparison – this time “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity already present in the “treated water” – which is the final tap water. (At this time the Hamilton water supply was not fluoridated).

Impurity Treated (mg/L) Added FSA%
Aluminium 2.04E-02 0.43
Antimony 8.00E-04 <0.04
Arsenic <1.10E-03 1.15
Barium 1.26E-02 0.03
Berylium <1.10E-04 <0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper 8.00E-04 0.15
Iron <2.10E-02 0.77
Lead 4.82E-04 0.05
Manganese 1.75E-03 0.20
Mercury <8.00E-05 <0.25
Molybdenum 3.70E-04 <0.10
Nickel 3.52E-03 0.11
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 4.82E-03 0.14

The extremely low levels of contaminants – both calculated and already in the intake water and final treated water – mean some of the calculations are rather meaningless. Especially as some of the analysed values are given as less than the detection limit.

However, the very low calculated contribution of contaminants from this fluorosilicic acid sample – usually < 1% of that naturally present – shows how ridiculous the Fluoride Free NZ claims about contamination introduced by fluoridating agents is.

Never trust anti-fluoride campaigners

Fluoride Free NZ is simply scaremongering – relying on naive chemophobia where just the chemical name and analytical data (even where the “<” symbol indicates below the level of detection) seem to scare people.

This example illustrates, once again, that the claims made by anti-fluoride and similar activists should never be accepted at face value. They should always be checked against reliable sources.

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Another defeat for anti-fluoridation claims about arsenic

Anti-fluoride campaigners make a song and dance about contaminants, particularly arsenic, in fluoridation chemicals. However, a new study shows there is actually nothing to worry about – and, in fact, these campaigners should be more concerned with natural sources of arsenic, than with fluoridation chemicals.

The study is:

Peterson, E., Shapiro, H., Li, Y., Minnery, J. G., & Copes, R. (2015). Arsenic from community water fluoridation: quantifying the effect. Journal of Water and Health.

Past studies estimated the arsenic contribution to drinking water from fluoridation using the arsenic concentration of the fluoridation additives. This new study went further and compared the actual arsenic concentrations of  1329 paired raw water and treated drinking water samples. The samples were taken from 121 drinking water systems in Ontario, Canada.

The graph below compares the mean values of arsenic concentrations in raw water and treated water for both fluoridated (49%) and unfluoridated systems (51%).


The data shows that even after treatment the concentration of arsenic due to natural sources is about 0.44 ppb. Fluoridation added a mere 0.07 ppb to this! (ppb = parts per billion = micrograms/litre = μg/L).

The authors concluded that fluoridation is associated with an extra 0.078 ppb compared with non-fluoridated systems when controlling for other factors (raw water concentrations, treatment processes and water source).

Let’s put these figures in context. The maximum acceptable value (MAV) for arsenic in drinking water is 10 ppb. So even the raw water mean concentration of 0.69 ppb (0.44 ppb after treatment) is safe. And the extra arsenic in fluoridated water is only 0.7% of the MAV!

Surely the sensible person will worry about natural sources of arsenic long before getting their knickers in a twist over the contribution from fluoridation.

I drew a similar conclusion from some New Zealand (Hamilton City) data in my article Fluoridation: putting chemical contamination in context. In that case, the contribution for arsenic from natural sources was much higher (around 30 ppb in the raw water – 3 times the MAV, and about 3 ppb in the treated water – a third of the MAV ).

New paper confirms previous studies

This new study confirms previous work based on the measured concentration of arsenic in fluoridating chemicals. That work produced regulations defining maximum permissible levels of contamination in water treatment chemicals. These are based on a maximum contribution of 1 ppb – 10% of the MAV.

Peterson et al., (2015) indicates the extra arsenic resulting from fluoridation is less that 10% of these standards. This is likely to be much less in Australia and New Zealand as the actual arsenic concentrations in the major fluoridating agent used, fluorosilicic acid, are much lower than those used in North America.

So – my message to anti-fluoridation campaigners is stop worrying about arsenic due to fluoridation. If you must worry then check out the concentration  of arsenic in your drinking water, and the raw water source, due to natural sources.

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Fluoridation: emotionally misrepresenting contamination

Another attempt by me to put the issue of contamination of fluoridation chemicals into proper context.

This time I am using data placed on-line by Sapphire Eyes Productions. They produced an emotional anti-fluoridation film Fire Water which relies heavily on the argument that fluoridation chemicals are waste products full of contaminating heavy metals. Trouble is – the data they put on-line does not support the argument – rather it destroys it as it shows that the measured levels of contamination are well below regulated limits.

You can find their data at Raw Fluoridation Chemical Analyses – Freedom of Information – South Australia Water Corp.: FOI Fluoridated Water Analyses for South Australia, 2006 – 2010.

I have extracted the relevant data – from the 16 certificates of analysis for fluoroslicic acid they presented. In the table below I compare the range of contaminant levels with the regulated maximum concentrations for New Zealand (quoted in  NZ Water and Wastes Association Standard for “Water Treatment Grade” fluoride, 1997). As mentioned in previous articles the specific impurity limits are calculated from the maximum acceptable value (MAV) of an element taken from the Drinking-Water Standards for New Zealand 1995. A further safety factor is used as described in the regulations:

“Specific Impurity Limits (SIL) have been calculated based on a maximum dosage (MD) of fluoride ion/litre of water and the maximum acceptable value (MAV) of a parameter taken from the Drinking-Water Standards for New Zealand 1995. The safety factor (SF) used in the calculation should be a minimum of 10, which reflects the view that no more than 10 percent of aMAV should be contributed by a given impurity in a water supply chemical.”

Put simply, the contamination from fluoridation chemicals should contribute less than 10% of the maximum acceptable value in the finished water.

Element Regulated maximum – ppm Range 16 certificates – ppm
Antimony 40 0.005 – <2
Arsenic 132 1.1 – 4.3
Cadmium 40 0 – <2
Chromium 660 0.6 – 7.3
Lead 132 <0.001 – <5
Mercury 26 <0.1 – 7.9
Selenium 132 <0.05 – <2

The data clearly shows that contamination is far lower than the regulated maximum in all the relevant cases. Even for mercury the high top end of the range was for only two samples all others would have contributed less than 10%

And remember less than 10% of the regulated maximum means less than 1% of the maximum acceptable value for drinking water.


So, don’t be taken in next time an anti-fluoridation activist goes on about waste products and contamination – even if they refer to specific analytical data. Insist on looking at the actual data and checking the levels against the regulations. Don’t be fooled by their tendency to flash the data and quickly move on (as they did in the Hamilton Fluoride Tribunal).

Remember, these days analytical methods can be extremely sensitive. Just because we can measure a contaminant concentration does not mean we should be concerned about it. After all, all our foods and drinks, natural or not, will contain almost any element at extremely low concentrations.We should always attempt to put the information into its real context.

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Fluoridation: putting chemical contamination in context

Anti-fluoridation activists often claim fluoridating chemicals used for water treatment are contaminated with heavy metals and radionuclides. I have written about this before in Fluoridation – are we dumping toxic metals into our water supplies?Water treatment chemicals – why pick on fluoride? and Hamilton – the water is the problem, not the fluoride!  The issue was also discussed in my exchange with Paul Connett (see Fluoride debate).

Trouble is, many people have difficulty putting measured levels of contamination into context. After all, if there is a sufficiently sensitive analytical method available just about any contaminant will be detected and measured in our food and water. The important issue is the magnitude of the contamination (which is often natural anyway). That is why measured levels of contaminants must be compared with the maximum allowable values defined in regulations for food and water safety.

I have seen anti-fluoridation activists presenting submissions to councils who will flash on the screen a copy of a certificate of analysis as “evidence” of heavy metal contamination without any reference to the measured values at all! Their logic seems to be that the fact contaminant levels have been measured at all is some sort of “proof” of dangerous contamination.

Arsenic in Hamilton City water

It may help to consider the possible levels of contamination with the contamination from natural sources. In the graph below I have plotted the relative contribution of arsenic from natural and fluoridating chemicals in the treated Hamilton City (NZ) water. Arsenic is commonly mentioned by opponents of fluoridation.


The source water for Hamilton (Waikato River) contains arsenic from natural sources usually 2 or 3 times the maximum acceptable value (MAV) for drinking water (10 ppb As) (McLaren and Kim 1995). (ppb = parts per billion). In the figure the first bar represents river water arsenic content just under 30 ppb. After treatment up to 90% of the arsenic is removed so that it does not exceed the  MAV  (here 3 ppb) – red horizontal line. However, the contribution from fluoridation chemicals used (assuming about 2 ppm As in the FSA – the last batch used in Hamilton had 0.4 ppm As) is miniscule (about 0.01 ppb) compared with that from natural sources. Too small to show in the above graph.

Seems to me rather silly to argue against treating Hamilton water with fluoridating chemicals because they are “contaminated” with arsenic while ignoring the much large contribution of arsenic from the source Waikato River water.

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