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Re: Aqua regia (was Aquatic Plants Digest V4 #372

Hello Roger,

While I agree with most of what you said, "aqua regia" -- "royal water"
-- is a mixture of nitric and hydrochloric acid (NOT sulfuric) and it
will dissolve metallic gold (hence the "royal").



> Date: Tue, 27 Jun 2000 13:50:16 -0700 (MST)
> From: "Roger S. Miller" <rgrmill at rt66_com>
> Subject: Re: fluoride "problem"
> On Tue, 27 Jun 2000, Neil Travis wrote:
> > I think you had better re examine your chemistry.
> > In Melb if we have any clay deposits in the water it completely chelates the
> > fluoride.
> "Chelate" is the wrong word.  Maybe "bind"?
> Fluoride substitutes for small amounts of hydroxide in some minerals.
> Clay minerals contain hydroxides in their "octahedral layer" so I imagine
> that fluoride may fit in there, too.  I think it's more likely that the
> flouride would substitute for hydroxides in precipitating iron or
> manganese hydroxides.  Once precipitated it would be there pretty much
> forever.
> > Say you have a 10% evaporation rate then you have 100% of the fluoride in
> > 90% of the water then you remove another 15% of total tank capacity and
> > replace it with 25% of tank capacity to fill it then you have 115% of
> > original Fluoride concentration and so on with every water change. Simple
> > mathematics.
> For the most part, I expect that fluoride in the water will be pretty
> unreactive and will just stay in the water until it encounters something
> with an unusual affinity for it.  But given enough time some precipitation
> will occur, and that may be sufficient to offset the evaporative buildup
> of fluoride in the water.
> > on distilled water I did not advocate using plain distilled but using it as
> > a starting point. I add salts to mine but at least I am sure it is fluoride
> > free as I have had many experiences with Fluoride egg hardening and after a
> > lot of experimentation and consultation with Melbourne water got it right.
> > Hardening of eggs is fairly obvious when you see a fish in an egg trying to
> > get out but can't and eventually dies.
> I checked and I have been completely unable to find evidence for fluoride
> affecting aquatic life.  There are no water quality standards for that
> purpose (the standards are for human health and aesthetics) and I've found
> no discussions of any other effects.  If there is a relationship between
> fluoride and low hatch success then the environmental regulators -- who
> tend to be sensitive to that sort of thing -- would *definitely* be paying
> attention.
> More likely there *is* no effect on fish eggs (despite the unscientific
> observation) and certainly no effect of fluoride on the health of
> anybody's bettas.
> Then Bob Dixon wrote:
> > I once asked a chemist friend about something to remove calcium and magnesium
> > from the water and precipitate it.  HFl came up as an option, but he assured
> > me that the flouride ions were reactive enough that my tanks would suffer
> > from its ability to dissolve glass.  Glass is also extremely "stable" but not
> > immune to flourides strong reagent ability.  So it would seem to me that
> > silicates in any form would not be safe from being knocked loose and replaced
> > by Fl ions.
> Hydrofluoric acid does etch glass and it does dissolve silicate minerals,
> but really Bob, there's a lot of thing that will happen in a concentrated
> solution that will never happen in a dilute solution like 1 ppm of
> fluoride in tap water.  For example, concentrated sulfuric acid and nitric
> acid together make an extremely corrosive, oxidizing acid called aqua
> regia that also dissolves many minerals -- even some that hydrofluoric
> won't touch.  We pretty much all have sulfate and nitrate in our tanks --
> and at levels greater than 1 ppm -- yet we aren't sweating their combined
> effects on glass, fish eggs, fish or whatever.  Those effects don't
> happen in dilute solution.
> If we have so much time on our hands that we can afford to worry about the
> possible effects of fluoride then maybe our time would be better spent
> worrying about the effects of chloroform and trihalomethanes (carcinogens)
> resulting from chlorination of tap water, or about the toxic copper and
> lead introduced to some tap water at microgram/liter levels just from
> flowing through the pipes in your house.
> Also, this thread is completely unrelated to growing aquatic plants.
> Roger Miller