Attack of the Fluorides

Answering a couple of statements on Fluoride and the fact I swallow toothpaste (rather than spit). I'm always up for a bit of science, I'm like Dr. Karl of teenagers sometimes (especially when there's alcohol involved). As opposed of course to the Mythbusters, where there's less science and more "bang."

"If you swallow too much, too often it can kill you"

The commonly accepted concentration of toothpaste is a simple 0.32% w/w (look on the back of your toothpaste container for you own observational data). Assuming that toothpaste has the same density of water and our test is at 25 degrees Celsius, that would mean the total mass of Fluoride content in one serve (as Na2PO3F) is 3.2mg.

A lethal dose of Fluoride is 23mg/kg of body mass (Robert H. Dreisbach PhD, "Fluorine, Hydrogen Fluoride & Derivatives" in the Handbook of Poisoning 9th Edition 1977). As such, for a adult my size (70kg) I would require to ingest 1610mg of Fluorine for a lethal effect. Or, in terms of toothpaste 503.125g. Half a kilo of toothpaste? Yup, sure... That toothpaste... Lethal...

"It will eat away at your gastrointestinal tract and may not even show symptoms until it's too late."

"It can cause dental fluorosis, bone fractures, bone cancer, infertility, neurotoxicity and periodical bone loss."

"You can experience convulsions, diarrhoea, difficulty breathing, drooling, heart attack, salty or soapy taste in mouth, slow heart rate, shock, tremors, vomiting or sickness"

Yes, again, I'm sure it can - in large quantities. However, if was so dangerous if you so detail, then why does every state in Australia (minus Queensland from memory, and they're discussing changing that because of dental problems) add Fluoride to their water? Oh, lets just add chemicals to our water without performing the checks of dangers to our community. In Australia, water has been treated with Fluoride to a concentration of 1mg/L (http://health.vic.gov.au). The average recommended quantity of water to drink per day is 2L, containing 2mg of Fluoride. Slightly less than the concentration of toothpaste, yet having that pass through you every day almost the same as swallowing (as opposed to spitting, factoring that you swallow some accidentally when you brush anyway).

This proves that swallowing toothpaste is no more dangerous than drinking Melbourne's water, arguably the best in the world.

"It is used to remove Iron stains"

Never heard this before, let's assume so considering it is the element with the highest electonegativity. Then, following this simple method, the only iron in our body is in our haemoglobin, as state Fe2+ or Fe3+ ions (VCE Biology and VCE Chemistry). Two observations can be made from all points so far:

Iron stains are different to Fe2+ and Fe3+ ions in Haemoglobin; and hence the effect of Fluoride on Iron in our body is irrelevant.

Not a single "sickness" you defined in the list above is a direct result of iron deficiency. Iron deficiency is most commonly noticed by "fatigue, weakness, brittle nails, Plummer-Vinson syndrome or an impaired immune function" (Source: Bedside clock books).

"It's used in insecticide mostly against cockroaches."

I found two common insecticides (out of six) that reported to both be designed for cockroaches, and contained Fluoride. Of these, both reported that they do not affect mammals(Raymond-Delpech V, Matsuda, Sattelle BM, Rach JJ, Sattelle DB (2005), Ion channels: molecular targets of neuroactive insecticides). So the obvious point here is: Yes, fluoride is lethal - for cockroaches. I however, am human, a mammal, and am not in the slightest affected by its use in insecticides.

And that is just the Fluoride, completely rebutted. What's next?