Re: GAS-L: burning arsenic

[Andrew Heggie <andrew.heggie@dtn.ntl.com>]

On Sun, 1 Oct 2000 01:42:08 +0900, you wrote:

>Pardon me, I'm not knowledgeable enough to know if this is a dumb 
>question or not: what happens to the arsenic (and other chemicals?) 
>in treated wood and sawdust when you burn it? Does it make for toxic 
>fumes or does it just break down harmlessly?

I am still reading up on this so cannot claim to be at all "expert": I
guess you are referring to wood that has been treated with a water
borne salt, chromated copper arsenate. I am certain chemicals from
this are volatilised during burning, also what remains is concentrated
in the ash. Arsenic and copper accumulate in the body but have known
half lives and are excreted in time, nasty but probably not life
threatening in a single dose. The chromium is far more insidious, in
the active salt it is the hexavalent form, most of this combines with
the wood and is held in the trivalent form, however some un reacted
chromium is free in the wood in the hexavalent form. I am told
combustion products and ash will be predominantly the hexavalent form,
as yet I have not verified this.
AJH
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