Aluminum ingestion from soda cans?

This is a different question than you may think.  

When you pop the top on a soda can, it tears the drinky hole part away from the lid.  Your beverage then flows past both the torn edge of the top and the lid.  On a very small scale, that rushing torrent might break off little slivers or bits of aluminum from those two edges.  Maybe it's super negligible, maybe not.  I just did a quick internet search but it was overpowered with discussion about aluminum leaching into the drink while sitting on the shelf (separate but important issue).

Might anyone know if this has ever been looked at?

I had never even thought of that! Good of you to think of such things.

I stopped drinking soda years ago. If I get an urge for something fizzy I go to the local Kwik Trip and buy a Kombucha. It comes in a dark glass bottle that I reuse for medicinal tinctures. I would call that a win.

No idea. But I have been in the back area of a grocery store when the “bug man” came through and sprayed all the soft drink cans.   I suspect aluminum might the least of our concerns.  I make sure anything I buy is in a box.

I had a high school teacher who directly addressed this issue.

It turns out that aluminum cans have a very, very, almost negligible coating of some type of plastic (and I use the term plastic very loosely.  It could have been a wax).  The reason is that the carbonic acid in the soda is highly reactive with bare aluminum.  To directly and dramatically demonstrate this point, my teacher (shout out to John Pearson if he is reading or anyone knows him!) popped open a soda can in class and then took a nail and scratched a line around the inside of the can so that the thin film was removed and bare aluminum was exposed directly to the acidic soda.  The next day, he VERY gingerly poured out the soda into a sink, then held the can in his hand and simply pulled the top third of the can off the bottom 2/3 of the can exactly where that line had been scratched.  Overnight, carbonic acid completely reacted with and removed the aluminum along that line and the next day the two pieces of the can were held together solely by the paint on the exterior!

So if a simple interior scratch will result in soda completely reacting/removing the aluminum in one night, I think we can safely assume that any can that lasts more than a day has a film lining that is still intact.  And if you had any question, simply pick the can up and give it a slight pull or push.  Any defect in the lining would have created a hole that would cause the soda to leak out before opening.

So with all that in mind, I think that we can safely assume that a can of soda just sitting on a shelf by itself will not pick up stray aluminum or the can itself would fail quickly.  It turns out that aluminum is pretty reactive so it needs protection to remain stable.

Now as far as bits of aluminum flaking off when opening, I cannot make any claim and have no knowledge.  But the can itself is safe from the soda and therefore the soda is safe from the aluminum in the can.

Do with this information as you wish.


Eric

I've heard the aluminium can coating described as a 'resin' (it would be curious to know more about that as the term can be applied to synthetics as well as the traditional plant products). But Mike's original question specifically goes to the opening where the air- and water-tight seal is broken to allow for consumption. It seems that maintaining that resinous coating in the area of the broken seal would be very difficult. Since the contents don't sit in contact with the exposed surface very long, and even so eating away at the rim would not affect integrity of the can the same way the scratch in the side did, such a coating would not be needed to make the cans functional, or noticed if it did not exist. I'm not a big chemistry guy, but it would seem that the contents of a can would not be in contact with that exposed surface for long enough in large enough quantities for any significant corrosion under normal use. However, the question remains, could the flow of fluid past exposed aluminium  physically 'wear' a measurable amount of the metal from the surface?

One comforting aspect of the question is that any such leachate would only be going through the digestive system, which hopefully would do its best to pass any toxin through the body to elimination. One reason there has been a good deal of concern about safety with aluminium in the body is that it is common in today's vaccines where it is directly injected into the blood stream/muscles, bypassing the normal safety barriers posed by the skin or the digestive tract. Safety testing of that process has been sketchy to say the least...

Coydon,

The term “resin” works for me.  Actually, it’s probably a better term than plastic or wax do let’s just go with resin and call it a day.

Thanks for the clarification.

Eric