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

[Vaughn Hopkins <hoppycalif at yahoo_com>]

That certainly argues against lead being the culprit if someone loses  
a tankful of fish.  I would expect lead poisoning to affect different  
fish and species of fish at different rates, so a lead poisoning  
problem would be a long drawn out series of fish deaths.  Also, lead  
oxides are insoluble in water, and the lead strips I use tend to be  
heavily oxidized.  One last comment:  (I know that anecdotal evidence  
is not good evidence, but)  I kept several fish, from clown loaches  
to SAE to Chinese algae eaters for about 4 years in a tank that had  
quite a few lead strips weighting down plants.  There were probably  
about a half dozen of those strips in the tank at any one time, since  
I tried to remove all of the old ones at every opportunity.  I had no  
problems at all with those fish.
If I kept expensive, long lived fish, like Discus or even angel fish,  
I would avoid any lead in the tank, but for the very small fish I  
keep, which tend to live about 2 years (guppies, for example) I don't  
see where there is a problem.  In any case, there is no question in  
my mind that avoiding lead in the tank is desirable.  I just don't  
believe that people lose a tankful of fish due to lead in the substrate.

Vaughn H.

On Sep 27, 2006, at 11:58 AM, S. Hieber wrote:

> 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

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