RE: Aqua Regia & safety

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From: Monnoyer Philippe (monnoyer@imec.be)
Date: 02/21/03-04:15:34 AM Z


Judy,

It's a bit hard for me to make the link between my post and your short reply. I think you interprated it beyond what I meant.
Indeed, it would be ridiculous to consider chemicals do present the same risk with a rated scale.
As for fattening agent though, all other conditions being equal, peanut butter will obviously win the race.

This was my absolute last mail on that topic.

Philippe

|
|
|Philippe, I have worked extensively with dichromate & not with
|aqua regia,
|but my feeling is it's simply impossible to rate the relative danger.
|I've read a lot of the 19th century literature about workers
|in dichromate
|who had hellacious agonizing skin lesions, without -- for nearly a
|lifetime -- a clue what caused them. I am most EXTREMELY
|allergic myself
|(I could get hives, when I was in full bloom turpentine allergy, from
|sitting in a chair that someone with turpentine on her hands
|had put her
|hands on 5 hours earlier, or using floor wax or shoe polish, which have
|turpentine, which is, I understand one of the two most allergenic
|substances to humans -- the other being chrome.)
|
|Yet, I have managed by keeping hands out of it, and other care, to use
|dichromate for 10 years and apparently OK ... Though I've
|found that even
|putting bare hands in final "clear" washwater, as I occasionally did in
|"emergency" at school, left me with discomfort in skin for a
|day. I also
|know that an occasional splash on bare legs of just a tiny dot
|of the gum
|soaking water that I didn't notice at the time, causes a burning itch
|within an hour or so... It's quickly removed by rinse with
|clear water --
|but it suggests to me all sorts of ramifications of danger.
|
|As for the turpentine -- I shudder to think of the classroom situations
|where each of 50 or even 20 students has an open palette with
|turpentine
|evaporating into the room. We had that in art school... I hadn't
|developed the allergy at the time, but it surely was a factor. And I'll
|add that my own turpentine allergy at one time was so severe I
|verged on
|anaphylactic shock.
|
|In other words, trying to "rate" the danger is not only moot, but not
|necessarily useful. It could cause someone to relax where they
|shouldn't,
|and panic where it's also beside the point. It's like trying
|to say which
|is more fattening, peanut butter or steak or Courvoisier. It depends
|where, how, how much, and who.
|
|As for that Hazards book, I found it absolutely useless. It
|has no sense
|of proportion, rating all hazards as if you were using
|industrial strength
|amounts for a 40 hour week. So you either discount it
|entirely, or give up
|at the outset.
|
|And to come back to the precipitating issue here, Liam's
|formula was for
|50 ml (less than 2 ounces !) of aqua regia, which was then
|diluted. That's
|about a shot glass full.
|
|And now, Philippe, since you seem a level-headed sort -- what do you
|think about working with ether, gun powder and rat poison, as
|has had NO
|warnings on this list, not a single solitary one, although
|wetplate is
|the latest rave, craze, passion.
|
|And, would you compare the danger of splash or fumes from aqua
|regia with
|Dutch mordant (the strongest etch for printmakers) or nitric
|acid, which
|we used all day long in open trays in print making, probably
|from 2 to 4
|litres in a tray, probably 4 or 5 trays in a room. Nobody said a WORD
|about danger -- it was assumed that we were adults and knew it
|was strong
|enough to bite metal.
|
|Judy
|
|


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