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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