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July 2004

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Subject:
From:
Karl Heinz Zuber <[log in to unmask]>
Reply To:
(Leadfree Electronics Assembly Forum)
Date:
Mon, 19 Jul 2004 10:38:32 +0200
Content-Type:
text/plain
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text/plain (153 lines)
Dear Friends,
if you are interested in Chinese recycling work conditions, please
contact greenpeace, they have, among other things, a video about that
which is very impressive. Of course, lead is not the only or even the
biggest problem for them. I assume that under the given circumstances,
vapors as well as particular lead will occur. 

I think I could send the video to interested persons; but you should
first try to get it from Greenpeace, i dont know if its available at the
internet. Probably you dont trust these silly "environmentalists", but
when i see the situation in china or india, i think its important to
have somebody who cares about that. The superior, clean technology that
solves all problems is a "myth", too, for most parts of the world.

On the other hand, this is a good example, that "recycling" is not the
"panacea" to cure all potential environmental problems, as it was
suggested several times in this forum. 

As to the "nontoxic metallic lead", it is not inert enough to expose it
to environmental conditions or biological processes withhout effect.
(refer to MERIAN "Metals and their compounds in the environment").
As to the threshold problem, we discussed it earlier; it is not
applicable for genotoxic effects. Also, an assumed threshold is not to
be seen as an "aim" for pollution that should be reached. There should
allways be a safety factor, because you practically cannot determine,
what exactly will happen to a substance in  environment. 

Best regards,
khz


-----Ursprüngliche Nachricht-----
Von: Leadfree [mailto:[log in to unmask]] Im Auftrag von Brian Ellis
Gesendet: Sonntag, 18. Juli 2004 09:50
An: [log in to unmask]
Betreff: Re: [LF] "lead vapors" myth


As far as I'm aware, metallic lead is not toxic per se, because it
cannot be metabolised. It is the lead compounds, starting with the
various oxides, that are toxic. That having been said, airborne lead
particles could be easily oxidised and sulfided. It should also be
mentioned that lead is not absent from the so-called "cosmic dust" or
micrometeoroids. In fact, scientists use the U:Pb ratio of these to
determine their age and origin. I cannot state the quantities but it is
not insignificant.

One thing that should be realised is that the toxic effects of lead (and
most other elements and compounds) are not linear. There is a threshold,
below which the effect is negligible. Above the threshold, the effect
can follow a law with an exponent of the mass absorbed of anything
between 1 and 2.

Another popular myth is that the toxic effects of lead are irreversible.
Sure, brain cells that have already been destroyed cannot be regenerated
but long term treatment with calcium EDTA and penicillamine will remove
the lead from the system and prevent further damage; at the same time,
it will eliminate all the other symptoms of plumbism (painful
gastrointestinal degradation, reduction of haemoglobin production
causing anaemia, gum disease etc.), which often kick in before severe
mental deterioration.

Brian

MA/NY DDave wrote:
> Hi Again IEEE-Harvey, Gordon, and IPC LF Listservers,
>
> A little add to your CA-Toxic Group, Alcatel-person, Chineese workers
tread.
>
> Be careful if they are pulverizing or creating SnPb dust (Is the
bottom
> line). By the Way this will probably not be specific to SnPb.
>
> In my early reading of the book I noted previously, from the
professors at
> the Univ of Naples (Castellino), it seems that particulate lead is the
main
> culprit for lead airborne intoxication and metabolism in organisms.
Gordon
> has been focussed on the gas state and it's effects yet maybe it is
the
> solid state in small particles that is the difficulty for plants and
us
> ANimals. Gordon did note this in his note.
>
> For Airborne Lead there is a base level almost without humans on-board
that
> was estimated by a person named Nriagu. It comes from natural
particulate
> matter sources (also known as dust). 24.5 x 10*3 tons would be a base
level
> without some of man's adds. Due to us all going into the metal age
(bronze
> age I think) we have added a pile of Lead and many more metals. I
guess my
> point is that even though we have added metals significantly to our
> ecosystem they would be there at some level anyway.
>
> So, Again I don't know the issues behind what you posted or the agenda
or
> knowledge of those you noted, yet I wanted to give a little bit more
> ammunition to engage the discussion and continue the learning.
>
>
>
> Yours in Engineering, Dave
> Y i Engr, MA/NY DDave
>
>
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