Reprinted from the ACJ - September, 2001
After I pick a subject and start to write these articles, I pretend I`m a Private Investigator. Searching for the seedy underbelly of hazard associated with the given subject. Latex gloves seem safe enough... but, aha, latex allergies. Gotcha! `Lead Free Solders, a Safe Alternative to Lead`. But wait; pigment changes due to excessive skin contact with copper. I knew it was too good to be true. Real `True Hollywood Story` type stuff. Find that one night of drunken decadence behind the outwardly pristine facade put forth by Header Epoxies. We all have our little secrets. I figured Aluminum couldn`t be as shiny and pretty as it appears.
Trench coat on, and mini-cam in hand I went after Aluminum. Not just the showy new cores, but the real Aluminum. The greasy frying pans, dirty baseball bats, pop top beer cans, antacids and buffered aspirin (see, drugs in every story). First the basics: Element #13, CAS # 7429-90-5, Atomic weight 27, Boiling point = 4200 F. Looks OK on the surface. Which, incidentally is coated with Aluminum Oxide, the tenacious layer that makes Aluminum (Al) so hard to solder. Modus Operandi- routes of entry: skin - no, eyes - no, inhalation - yes, ingestion - yes. That seems pretty straight forward. No magazine subscriptions needed to win. That skin & eye thing seems to good to be true. Sources close to the metal state that there are no adverse skin effects from contact with the metal. Unless you count cutting yourself on the pop top. Eyes; transient irritation, as with dust, but no long term hazard. It`s like tracking your wife to a strange address. Busting in to catch her in an affair and discovering she is picking up a custom tailored fly fishing vest for your anniversary. Lots of suspicion, but no crime.
So if there is no problem on the surface (of eyes and skin that is) what about deeper? Inhalation and ingestion. Surely `users` of this demon metal will pay a hefty price. According to OSHA and the Agency for Toxic Substances, a single or occasional inhalation of Al or the oxide dust yields no adverse effects. At least not any that are worse than dust from a gravel road. Transient coughing and an increase in asthma symptoms. Prolonged and repeated inhalation can cause Pulmonary Fibrosis, a scarring of the lung tissue. But that is the same as with any benign dust. Boy, this stuff is going to make a very boring `Behind the Music` special. Wait here is something. Ingestion of Al may be linked to Alzheimer`s disease. Digging deeper the truth comes out. Maybe, maybe not. This correlation is based on research involving Kidney Dialysis Patients and the fact that many develop tremors, speech problems, convulsions and symptoms of dementia after extensive treatments. Of course the dialysis fluid used contains hundreds of times more Al than water or foodstuffs. But what about the 10 to 30 times higher levels of Al that is commonly found in the brains of Alzheimer`s Patients? Turns out that respected researchers in the field cannot confirm whether the Al accumulation is a cause, or a result, of the disease. Test`s run on laboratory animals cannot induce Alzheimer`s type changes in the brain. Nor do dialysis patients show the forgetfulness or confusion associated with Alzheimer`s. Another dead end, or at least a Cull de Sac, to be visited again as more research is conducted. You smell smoke from under your kid`s bedroom door. You fling open the door to find... a candle light prayer circle in progress... Hi kids, want some cool-aid? Foiled again.
Enough undercover work, let`s grill the suspect under hot lights. What about Al intake from cookware? Amounts are negligible compared to the levels naturally occurring in food. What about in water? No, the levels are very low and the Al is in a form not easily absorbed by our bodies. Can fumes get us? Very little Al fume evolves below the boiling point of 4000 F or so. Carcinogen? No studies have linked Al to cancer. Although, chronic injection of Al into the lung lining (don`t try this at home) does cause Shaver`s disease. A lung tissue scarring disorder. What about bioaccumulation? Studies show no build up of Al in our body tissue over time. It passes right through. A regular Choir Boy.
Obviously, I`m at the `Columbo - one more question if you don`t mind` stage. So, what are the largest sources of Aluminum we are exposed to? Hot tea leaches a good share of Al from the leaves when brewed. Buffered aspirin and antacids that use Aluminum in their formulations are also a higher than usual source of Al.. One more note, any Al in your stomach is absorbed by your body better in the presence of citrus juices.
No dirty pictures, no clandestine hazards, no sleazy underworld connections. Conclusion: Working with Aluminum in the shop, using general exhaust and excepted hygiene practices, is safe based on the most up to date research. But, watch out if you are washing down antacids with lemon tea. Aha, Gotcha!
The above article was written by David M. Brown, Chief
Engineer of Johnson Manufacturing Company, Inc. and is published by
JOHNSON with the expressed approval of the National Automotive Radiator
Service Association and the Automotive Cooling Journal. Other reproduction
or distribution of this information is forbidden without the written
consent of JOHNSON and NARSA/ACJ. All rights reserved.
JOHNSON MANUFACTURING COMPANY
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