I followed that link,

"..Two pounds of root killer contain 0.5 pound of pure elemental copper
enough to contaminate 20 million gallons of water..."

It makes you think, doesn't it when you see those kinds of numbers...

Jim

-----------------------------

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of William Chops Westfield
Sent: 01 March 2004 23:15
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: ] My first PCB production


On Monday, Mar 1, 2004, at 13:54 US/Pacific, Spehro Pefhany wrote:

>
> But my wife, who is an expert in wastewater and other environmental
> technical and legal matters, thinks a bit down the home drain with lots
> of water isn't a technical problem.
>
>
Note that in the US, it is relatively common (or WAS relatively
common, anyway) to dump a couple pounds of copper sulfate down
your toilet to kill roots that might have been invading your
underground pipes.  Or something.  (Not that everyone is happy
with this: http://www.city.palo-alto.ca.us/cleanbay/pdf/root.pdf )

Copper sulfate is also pretty widely used as an agricultural
fungicide.

If you get up to several ounces of copper per year (at 1oz per
square foot of typical PCB, so, serveral square feet of finished
PCBs), you should probably start thinking about being nicer than just
flushing your used etchant down the drain.  But that's a awful LOT
of PCBs for the average hobbyist...

BillW

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