My thoughts were basically this, since I don't cook or drink from anything aluminum, don't eat flour products with aluminum in them or use deodorant with aluminum in it, why should I continue to breath from it.
Aluminum is a reactive metal. When you cook acidic foods in it, the acids react with the aluminum metal to create aluminum salts. The aluminum ions are readily dissolved by the polar water molecules in the food you are cooking. I won't bother with trying to list every acid, but just taking hydrochloric acid as a simple example, you'd have:
2 Al + 6 HCl --> 2 AlCl3 + 3 H2
If you have a hard anodized aluminum vessel, the anodizing process passivates the surface. With no bare aluminum, acids as found in foods will not react with anything, and no aluminum salts will be created. (Still, I like well-seasoned cast iron or clad stainless for my cooking, with an occasional non-stick pan for egg-based dishes. Aluminum's low heat capacity and high thermal conductivity make for an interesting combination with my non-gas stove.)
As for drinking from aluminum, if you were drinking highly acidic beverages from bare aluminum cans, the beverages may react and create aluminum salts. However, even though many beverages (especially mass produced carbonated beverages) are considerably corrosive, the aluminum is not exposed to the beverage. The inside of the can has a protective coating for the same reason as aluminum pans are anodized; without it, corrosion would be an issue.
As for "flour products" with aluminum, I suppose you would be speaking of "self-rising" flour. The aluminum compounds in self-rising flour are from "baking powder" added to the flour. Aluminum-based baking powders are the most common variety out there. They are usually double-acting (meaning they evolve gas when wet and again when heated), but according to some people, they create a slight metallic aftertaste in some products in which they are used. I would tend to agree; although I have not done a double-blind test, I have on several occasions correctly identified pancakes and waffles made with aluminum-based baking powders. Regardless, with aluminum-based baking powders, you are directly consuming soluble aluminum compounds. (As a side note, I have never purchased self-rising flour. If I need it to rise, I'll add the proper proportion of baking soda and baking power, Rumford brand [non-aluminum], and sift it through.)
Most antiperspirants also contain aluminum salts, although deodorants that are not antiperspirant do not contain aluminum salts. I have not studied the absorption of aluminum salts through the skin, but it seems plausible, especially considering the current trend toward "patches" for through-the-skin delivery of far more complex compounds.
Now, the thing to note about all these things is that it is aluminum salts that are soluble, and that they are soluble in liquids (specifically in polar liquids, such as water). Aluminum oxide, such as could potentially be found in a scuba cylinder, is not an aluminum salt and is not soluble in water. Aluminum metal is, of course, also insoluble (you don't see tanks dissolving and exploding mid-dive. :biggrin: I would hope it is patently obvious that no aluminum-based compounds or salts are soluble in *gases* (such as the air in your tank).
The only potential for consumption of aluminum from a scuba cylinder would be by inhalation of aluminum oxide. Most aluminum oxide created in the cylinder will adhere to the surface. What slight amounts may become free do not easily become airborne. The dip tube (snorkel tube, whatever) on the valve will prevent any loose oxide from entering the air stream when you're inverted, and if you do have aluminum oxide passing through the valve, you have the regulator's sintered filter on the first stage which will rapidly be clogged if more than a trivial amount of aluminum oxide passes into it. As the few cases of regulators failing to supply air due to white aluminum oxide occluding the first stage's sintered filter are notably unusual and (in my reading) linked to missing dip tubes on poorly maintained tanks and valves, it seems perfectly reasonable to conclude that inhaling aluminum oxide is not of significance.
Frankly, the only health effects I can see from which to base a choice of aluminum versus steel are the following:
- Will purchasing more expensive steel tanks be such a financial burden as to change your eating habits, possibly creating the potential for malnutrition?
- Will having a bit higher dry weight significantly increase the potential for physical injury (back, joint, or muscular injuries)?
