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