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Re: E-M:/ Algae Used to Recover Toxic Heav...



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Enviro-Mich message from Rane Curl <ranecurl@engin.umich.edu>
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On Fri, 24 May 2002 RobC313@aol.com wrote:

> In a message dated 5/24/2002 11:04:22 AM Eastern Daylight Time,
> Cubbagec@aol.com writes:
>
> > "Lead and cadmium both have numerous valuable uses"
>
> Pardon the tangent, but is it true that these toxic metals do have valuable
> uses?  I don't know much about all the uses for lead and less about cadmium
> but I do know that we once assumed mercury also had numerous valuable uses
> but now know that every, (nearly every?) use of mercury can and should be
> substituted with a less toxic material.  Any substitutes may initially cost
> more but when we consider the total cost to society perhaps higher initial
> costs actually become cost savings.

Many quite hazardous materials are used to maintain our level of
civilization and our "standard of living". What is needed is to
control the use and recovery of these materials so that we are safe
from them.

Probably the most lead you have in your home or business today is in
the lead glass used in computer monitor and television tube glass.
This protects us from x-rays generated in the tubes. I don't know
the extent to which this can be recycled into new lead glass, but
probably a lot enters the environment eventually. (Older uses -
in paint, anti-knock, and pipes are mostly phased out, while there
is still some used in solders, and a number of alloys.)

Cadmium in your home is mostly in nickel-cadmium batteries. It is
also used to make a yellow pigment for paints, but that use, and
also its use as an initial metal plating under chrome plating is
being phased out. It is also used in blue and green phosphors in
color television tubes (another reason for not breaking such tubes,
and properly recycling them). The battery use may eventually be
replaced by nickel-metal-hydride batteries  (which aren't totally
innocuous themselves, of course).

Incidentally, a lot of "recycling" of these materials is not "recovery".
Batteries now go to hazardous waste site storage. Perhaps someday they
might be mined for these metals - and even then perhaps just to bury
them somewhere safer!

--Rane Curl



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