Re: [APD] Caution with lead weights -- Or - Ethyl's Nails

["S. Hieber" <shieber at yahoo_com>]

Lead doesn't have to dissolve quickly to to be toxic. The effects are cumulative over the lifetime of the organism so low prolonged doses can add up to trouble -- iut'st he totatl exposure that counts. 
 
Btw, some, if not most, of those lead weights nowadays are actually zinc weights.
 
 
Lead or zinc weights can corrode in hard water, too.  When oxidized and mixed with a suitable liquid binderl, lead makes a terrific white basee for paint.
 
At what levels are either zinc or lead harmful to fish? It's somewhat controversial at what level they are harmful to humans, much less fish. But it's harmful enough that the Petro industry decide many decades ago to go with "Ethyl" as the name for the gasoline additive rather "tetraethyl lead" or the simple "lead."

If you use iron-bearing product for a weight, you cn consider yourself slowing boosting the iron trace levels in the aquarium. Some folks bury nails for that reason only. Others bury nails in backs for fun or profit, but that's entirely different. 
 
sh
 
* * * * * * * * * 
The deadline is Oct 12 for getting the special Convention room rate! 
 
Read about the Aquatic Gardeners Association Convention at 
http://www.aquatic-gardeners.org/convention.html 


----- Original Message ----
From: Vaughn Hopkins <hoppycalif at yahoo_com>
To: aquatic plants digest <aquatic-plants at actwin_com>
Sent: Wednesday, September 27, 2006 1:14:10 PM
Subject: Re: [APD] Caution with lead weights (was Re: Keeping Plants Rooted with MTS)


Did you eliminate the possibility that excess CO2 is what really  
killed those fish?  Vinegar is a weak acid, which will very slowly  
dissolve lead.  Vinegar has a pH of 2.4 to 4, depending on who you  
believe, but I haven't yet heard of an aquarium having a pH nearly  
that low.  My intuitive belief is that a  pH 5 aquarium will not  
dissolve lead nearly fast enough to ever be a problem, especially  
with weekly 50% water changes.  Am I really wrong?  I ask because I  
generally use a few lead weights, so there is usually some lead in my  
aquarium.

_______________________________________________
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com
http://www.actwin.com/mailman/listinfo/aquatic-plants