Brian,
I find your note more than a little insulting. Kay is a professional and
isn't taking positions based on who pays her salary. If she didn't agree
with her employer, she could always leave for another job.
Secondly, I think people will find recycling a lot more expensive than
they realize ... I'm not against it ... who can fight motherhood and
apple pie??
Thirdly, all of these metals/compounds came out of the ground in the
first place ... judicious use of knowledge and science should be able to
provide for a safe return.
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Monday, November 08, 1999 9:47 AM
To: [log in to unmask]
Subject: Re: [LF] Long-term solutions
Kay
Obviously, you have to protect tin, that is what you are paid for.
However, would you **willingly** ingest just 5 g of any tin compound,
organic or inorganic?
I repeat, no-one knows what reactions may occur in a landfill, simply
because no-one knows what is in water that reaches tin. It MAY be
perfectly benign, it MAY not. Furthermore, on the average PCB, apart
from oxidised tin, there are a neat variety of organic acids readily
available to reduce it!
Going back to the start of this thread: it is my honest belief, ITRI
notwithstanding, that the presence of all anthropo-sourced metals,
beyond trace quantities, is undesirable in the environment. Sooner or
later, as more knowledge is gained, they will probably all be restricted
therefore they must be recycled to the maximum, tin and lead both. If
they are recycled, why ban them?
Of course, I understand that the ITRI would prefer otherwise a) because
they receive their funding from tin production and b) because they would
prefer that solder contains 95%+ Sn, rather than 63%. I have no vested
interest in what I say, other than hoping electronics production may
continue as economically and as easily as possible.
Best regards
Brian
Kay Nimmo wrote:
>
> Dear Brian
>
> I would just like to clear up some of the points you make on toxicity
of tin. It is inaccurate to say that many tin compounds are toxic as
distinction should always be made between organo-tin compounds and all
other forms of tin. It is also inaccurate to generalise and claim all
organotins are toxic. The toxicity is not specifically related to the
tin, but to the nature and number of the organo- groups attached. See
the paragraph below.
>
> As far as the comment on cans is concerned the lacquer coating is in
fact there to prevent corrosion. In some cases a lacquer coating is
deliberately not used in order for the tin to dissolve to a small extent
in the acid food juice and stabilise colour and (apparently) taste. Take
a look at your cans of tomatoes/beans etc and you will find that they
are unlacquered, or only partially lacquered.
>
> The effect of distribution of tin metal in the environment has been
well examined. In particular, the US Fish and Wildlife service made an
extensive study on tin toxicity during approval of tin as lead-free
shot. Data on the behaviour of tin in soils, water, wildlife, livestock
and man was examined with tin succesfully passing this stage of the
approval process.
>
> Kay
> ITRI
>
> Organotins: toxicity is related to the precise nature of the
organo-moiety. Essentially, there are four basic types: mono- (with one
organic group attached to the tin), di- (with two), tri- (three) and
tetra- (four). As a generalisation, toxicity is greater for tetra- and
tri- types than for di-, which in turn is greater than for mono-.
However, within each type, it is the nature of the organo- groups
attached to the tin that is important. With regard to mammalian
toxicity, methyl- and ethyl- groups generally give the highest toxicity,
whereas larger alkyl groups (e.g butyl-, octyl-) are less toxic to
mammals, but are often more toxic to other species. For example,
tributyltin compounds (e.g. TBTO) are particularly toxic to marine
organisms, and are therefore used in antifouling paints to prevent
barnacle growth on boat hulls. This is the application that TBTO was
developed for. However, it is important to note that most of the di- and
mono- organotin compounds used commerci!
!
!
ally
> (e.g. in PVC stabilisers, catalysts, tin oxide film precursors) are of
low toxicity, and some are approved for food contact applications (as in
PVC packaging). The main message is that it is wrong to generalise and
say that all organotins (or, indeed, all tin compounds) are toxic.
>
> -----Original Message-----
> From: Brian Ellis [SMTP:[log in to unmask]]
> Sent: 05 November 1999 10:35
> To: [log in to unmask]
> Subject: Re: [LF] Long-term solutions
>
> I agree, but tin is also a severe issue which has not been
sufficiently
> addressed. Many tin compounds are toxic (some organotin compounds are
> used as wood preservatives, fungicides, algicides etc.). Who knows
what
> reactions may occur in a landfill? Anyway, tin is (or at least was)
not
> federally regulated in waste water in the USA, although I believe some
> States may cap it at 5 - 10 ppm. However, in Europe, the levels are
set,
> mostly at 1 - 5 ppm (copper at 0,5 - 2 ppm in many countries as a
> comparison). I won't discuss Malaysia's limit at 0,1 ppm, because this
> is a special case. Anyway, tin is considered about half as toxic as
> copper, so don't consider it as being exempt from all future
regulation.
> Note that many tin-plate cans for acid foods are now polymer-coated as
> additional protection against the ingestion of tin salts.
>
> I think the crux of the matter is that ALL metals can be shown to be
> toxic in some form or another. Lead is just a technocrat's buzz-word
and
> should not be treated differently from any other metal. When these
guys
> cotton on to these facts, all metals will be banned, as will also
> bromo-bisphenols used for fire-retarding PCB laminates. There is only
> one logical solution: obligatory recycling of all metals. The sooner
> this fact is realised, the better: then we can get on with our
business
> of soldering boards with tin/lead solders to our heart's content. AND
I
> say this as one much and actively concerned with the protection of our
> environment.
>
> Brian
>
> "Bernier, Dennis" wrote:
> >
> > Though I am not an advocate of rapid changeover to lead-free solder
alloys
> > without more reliability testing, I can see the lead-free alloys
might be a
> > future environmental problem. However, the amount of silver and
copper
> > combined in the solder will only be about 10% of the amount of lead
in
> > Sn63Pb37 solder alloy used now. This will be a very small amount of
metal
> > contamination due to the solder in the electronic product. It seems
then
> > the copper may become the issue because there will be 20-50 times as
much
> > copper in the assembly than silver.
> >
> > -----Original Message-----
> > From: Carol Handwerker [mailto:[log in to unmask]]
> > Sent: Wednesday, November 03, 1999 5:56 AM
> > To: [log in to unmask]
> > Subject: Re: [LF] Long-term solutions
> >
> > In the Assembly Processing group working on the Lead-Free Solder
Roadmap at
> > the IPC meeting, the highest priority item from the group was to
ensure
> > that the new alloys are viable in the long term from a toxicology
and
> > environmental life cycle point of view. Having to change alloys
again in
> > three years would be a waste of resources if we can formulate a
proper
> > solution now.
> >
> > At 07:06 PM 11/02/1999 -0800, you wrote:
> > >All,
> > >
> > >As I read the debates ongoing, it strikes me that there are 2 major
focus
> > >areas right now:
> > >
> > >1) Technical solutions to Pb-free solders
> > >2) Is the decision environmentally correct?
> > >
> > >Are we missing a 3rd item?
> > >
> > >Regardless of what solder we end up with, how does the industry
position a
> > >long term, environmentally sound policy that will forestall future
green
> > >initiatives from causing such upsets?
> > >
> > >The history of Pb is rife with abuses -- Workers not following safe
> > >practices, employers not requiring or implementing safe practices,
emission
> > >controls not being in place on smelters, .... This is in addition
to Pb
> > >being used without a full understanding of the toxicology and
exposure
> > risks
> > >(Paint, gasoline, plumbing The point is, past uses (and abuses)
and
> > >handling of Pb has created the situation we are in now.
> > >
> > >I have not seen/heard any discussion on establishing practices and
> > protocols
> > >that will foster responsible use of any solder -- Both safe working
> > >practices on the production end, and End of Life management. Should
this be
> > >part of the overall strategy, or a recommended best known method?
How does
> > >this link into product takeback requirements that are gaining
popularity in
> > >the EU and Japan?
> > >
> > >Regards,
> > >Paul Wermer
> > >(Whose opinions are his own and do not necessarily reflect those of
his
> > >employer)
> > >
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> > Carol A. Handwerker
> > Chief, Metallurgy Division
> > NIST
> > 100 Bureau Drive Stop 8550
> > Gaithersburg MD 20899-8550
> > Office:(301) 975-6158
> > Fax:(301) 975-4553
> > e-mail:[log in to unmask]
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> Please visit IPC's Center for Lead-Free Electronics Assembly
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> Please visit IPC's Center for Lead-Free Electronics Assembly
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> For technical support contact Gayatri Sardeshpande [log in to unmask] or
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IPCWorks -October 25-28 featuring an International Summit on Lead-Free
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Assemblies.
Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Gayatri Sardeshpande [log in to unmask] or
847-790-5365.
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Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Gayatri Sardeshpande [log in to unmask] or 847-790-5365.
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