The safety of water fluoridation still seems to be a question on some people’s lips despite the failure of many studies (of both natural and artificially enhanced fluoridated water) to demonstrate any harmful effects at 1ppm.
There was a landmark court case in Edinburgh in Scotland in 1983 which saw a judgement passed in the favour of the safety and usefulness of fluoride- an opinion backed by numerous governement services and a systematic review of all the studies carried out by New York University.
If an excess of pretty much any chemical is taken, it can be toxic and fluoride is no exception. I guess the reason fluoride is contentious is because we add it to lots of things, which theoretically would increase the risk.
There are many elements found naturally in water that would be toxic in high doses; chlorine, sodium, calcium, magnesium, potassium and iron to name a few. And this is not considering the chemicals that get into our water supplies from various industrial processes. The pesticides and chemicals used in agriculture are far more of a concern to me personally. Have a read of this wiki page on water pollution
if you want to scare yourself with all the rubbish that can get into our water supplies.
To reach a level where a child would need to go to hospital, 5mg of fluoride per kilogram of body weight is needed. That would mean a 5 year old (say they weigh an average of 20kg) would have to swallow:
10ml Mouthwash (0.05% F) -as it contains 10mg/ml
5ml of a Varnish (2.2%F) -as it contains 22mg/ml
100 2.2mg tablets (NaF) -as they contain 1mg fluoride
35 drops of fluoride -as it contains 0.5mg/ 1 ml contains ( 1 drop = 0.5ml )
Over a large tube of standard (0.8%) fluoride toothpaste.
This highlights the importance of storing fluoride safely away from little hands.
If this was to happen, you should go immediately to hospital to have it removed from their stomach, as this is where the fluoride is mostly broken down and absorbed. The doctors most often begin this process by giving an emetic to try to induce vomiting. If a child has swallowed less than 5mg- a large amount of milk can help to neutralize the fluoride. If you are concerned at all, call your doctor or Accident and Emergency.
There is no evidence to suggest that areas supplied by fluoridated water experience higher cancer rates than normal.