How to source Chromium, Fluorine, and Selenium

Lousybreed · Nov 22, 2020

I am zeroing in on my DIY trace element potion.....Does anyone have any tips on how to best buy Chromium, Fluorine, and Selenium. I am kinda striking out on finding actual chemical sources......I have found supplements but I want to avoid buying supplements because I don't know what additional things are in them.

Lousybreed · Nov 23, 2020

All my fellow chemistry nerds....any help out there?

Randy Holmes-Farley · Nov 23, 2020

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Randy Holmes-Farley · Nov 23, 2020

Edit: out of an adundance of caution for aquarist safety from mishandling, I removed this recommendation. See other choices later in the thread.

Randy Holmes-Farley · Nov 23, 2020

Not sure how much selenium you want, but there are many suppliers of sodium selenite, which is suitable:

Nutricology Selenium offers a pure sodium selenite solution, which is well absorbed and may be suitable for individuals who are sensitive to other forms of selenium.

www.nhc.com

Randy Holmes-Farley · Nov 23, 2020

These compounds can be toxic, so be careful with them.

flampton · Nov 23, 2020

Yes in fact I wouldn't get the chromium at all without having a chemical hood. It's really really dangerous.

If you can source some trivalent chromium that would be much much safer and better for your tank.. Like CrCl3

So even though trivalent chromium isn't the main chromium in seawater it's the biologically useful one, as chromium (VI) has no biological function and in fact it's just straight up toxic to life.

Randy Holmes-Farley · Nov 23, 2020

flampton said:
Yes in fact I wouldn't get the chromium at all without having a chemical hood. It's really really dangerous.

If you can source some trivalent chromium that would be much much safer and better for your tank.. Like CrCl3

So even though trivalent chromium isn't the main chromium in seawater it's the biologically useful one, as chromium (VI) has no biological function and in fact it's just straight up toxic to life.

I presume one is dosing to not more than natural levels, so I do not think it will matter if he doses the form I suggested, and they will itnerconvert. I agree safety is a concern for using it.

That said:

Redox Processes of Chromium in Sea Water

Chromium exists in natural waters in two oxidation states, Cr(III) and Cr(VI), that are characterized by different chemical behaviour, bioavailability and toxicity. Dissolved Cr(III) has a strong tendency to adsorb to surfaces (Cranston and Murray 1978) and is...

link.springer.com

"Cr(VI) is much more bioavailable to aquatic organisms than Cr(III)"

"Dissolved Cr(III) has a strong tendency to adsorb to surfaces (Cranston and Murray 1978) and is characterized by a low solubility. "

"Cr(VI) forms anionic oxy-compounds that also have an adsorption affinity for certain proton-specific mineral surfaces (Zachara et al. 1987). However, their adsorption is limited in sea water where both Cr(VI) species and particle surfaces have negative charges, and high concentrations of sulfate (0.028 M) compete with chromate for adsorption sites. "

flampton · Nov 23, 2020

It's more bioavailable to be toxic as it has no biological function. It causes lung cancer, other cancers, sterility, eye damage, skin damage, allergic reactions and if inhaled serious respiratory burns and potential death.. So I'm not really concerned about toxicity and fish here, however...

MSDS

https://fscimage.fishersci.com/msds/21130.htm

Btw
Same abstract...
The competition between Cr(VI) and sulfate is responsible for significant changes in the bioavailability and toxicity of Cr(VI) in estuarine waters where sulfate concentrations increase markedly with salinity (Riedel 1984; Riedel 1985) Cr(VI) compounds are toxic due to their oxidation of intracellular compounds and are also known as a human carcinogen and mutagen.

So sulfate will help control the toxicity in a marine aquarium because it competes with Cr(VI) for uptake, but only up to a point (the two reidel papers) however what's to help the person working with a chemical that can seriously harm them, doesn't likely have a fume hood, eyewash station, other ppe?

Randy Holmes-Farley · Nov 23, 2020

flampton said:
It's more bioavailable to be toxic as it has no biological function.

Seasonal changes in speciation of dissolved chromium in the surface Sargasso Sea

Seasonal changes in speciation of dissolved chromium in the surface Sargasso Sea

The concentrations of Cr (III) and Cr (VI) were determined in the upper 500m of the Sargasso Sea at different times of the year. Total Cr concentratio…

www.sciencedirect.com

"Although Cr (VI) is toxic to phytoplankton in freshwater systems, the toxicity in seawater (up to a concentration of 1.9 umol l1 ) is negligible (Frey et al., 1983); thus the uptake of Cr (VI) by phytoplankton and its subsequent reduction to the less-toxic Cr (III) is not thought to be a detoxification mechanism (Bopp and Ehrlich, 1988). A more likely explanation for the reduction process is that phytoplankton are able to use Cr (VI) as an electron acceptor in some cellular chemical reactions (Lovley, 1993)."

flampton · Nov 23, 2020

I don't know what you're trying to win here? I mean you realize you're battling for the OP to get a extremely dangerous oxidizer for no known positives? Besides the known massive health risks, what if he stores it next to his rubbing alcohol and newspapers? I mean in a modern laboratory this compound is stored with extreme caution, only used in a hood with extreme caution, and every little bit of waste product is stored for chemical safety to remove and dispose of properly.

so to continue with the chromium(VI) not being important to your aquarium...

Yes phytoplankton can detoxify it by photoreduction as outlined in this paper from 2009. But so what. If I lived where there was a decent amount of Cr(VI) I would want to be able to detoxify it too.

https://www.sciencedirect.com/science/article/pii/S0141113609000245?via=ihub

Light irradiation was essential to drive the reduction of Cr(VI) by marine phytoplankton, because Cr(VI) is thermodynamically stable in the presence of oxygen, its reduction in aerobic environment is an endergonic process, requiring investment of energy from an external source. To our knowledge, this was the first time that marine phytoplankton itself could achieve the photoreduction of Cr(VI) was confirmed.

_____

Now that purported enzyme thing that one group made up well that comes from....

The author Lovely (1993) who was working on Desulfovibrio vulgaris (a anaerobic bacterium) and found that it utilizes cytochrome c3 in concert with H2 to reduce chromium. Which helps the cell detoxify it, just like our cytochromes can help detoxify things.- This was then wrongly extrapolated to suggest phytoplankton does something similar. The key to remember is this is going to be a energy dependent process to reduce the chromium in a oxidizing environment. It is not something that is helping the cell other than detoxifying the chromium (VI). You want it gone, it is a strong oxidizer!!! And as for D. vulgaris well it has an easier time reducing chromium (VI) because it is living in a anaerobic environment (a reducing environment.)

Oh and I had thought science had gotten a bit further but it turns out in reality we only think so far that chromium(III) is important for humans and other mammals, and this science is disputed. Which means chromium(III) effects are not even slightly understood in other organismal groups.

So I change my opinion and say don't bother with chromium at all, it's likely going to do nothing positive. And I think you'll find this with a lot of the other constiuents of seawater being of no importance to the general health of an aquarium.

Randy Holmes-Farley · Nov 23, 2020

flampton said:
I don't know what you're trying to win here?

I'm not trying to win anything. I'm correcting false statements that you make.

You may well be right that Cr(III) is a better form to dose. Or maybe not.

I agree it is potentially safer for the user.

But claiming organisms do not use Cr(IV) is not the way to convince me.

Randy Holmes-Farley · Nov 23, 2020

flampton said:
. And I think you'll find this with a lot of the other constiuents of seawater being of no importance to the general health of an aquarium.

I certainly agree with that. Getting people to dose things like lithium and barium just because the tank water does not match seawater by ICP is causing more angst than benefit, IMO.

Randy Holmes-Farley · Nov 23, 2020

Lousybreed said:
I am zeroing in on my DIY trace element potion.....Does anyone have any tips on how to best buy Chromium, Fluorine, and Selenium. I am kinda striking out on finding actual chemical sources......I have found supplements but I want to avoid buying supplements because I don't know what additional things are in them.

If you want to go with a chromium 3 form for safety reasons, these may be good choices:

Chromemate - Chromium Supplement | Hammer Nutrition

Micronutrient with massive benefits Enhances carbohydrate metabolism Helps diminish sugar cravings | Hammer Nutrition

www.hammernutrition.com

Chromium(III) chloride hexahydrate, Certified® Reagent Plus 30g | eBay

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flampton · Nov 23, 2020

What false statements did I make? I think we maybe are going by different definitions? For me biological functions are those essential to maintain health of an organism, this was unclear so I do apologize. I probably should have said that they're not essential to the health of the organisms but sometimes chromium (VI) can be metabolically altered by them.

E.g. Organisms like D. vulgaris can reduce elements like chromium (VI) and Uranium (VI). Yet the only benefit they get is not to deal with the toxins in their environment anymore. Same with the phytoplankton and using photoreduction. Some seem to be able to use these metals as electron acceptors, but it's more of a double shot, they get reduction (detoxification) and a bit of energy. Yet none of these organisms that I can find are exclusive to anyone metal, and usually only use these metals when they don't have enough of their primary reductant available, sulfate, nitrate etc... This is likely very important for their niche, so it could be thought of as similar to our liver and the detoxification of various metabolites.

And one more thing. If I didn't think it was risky to handle the compound outside a laboratory I'd say if you want to do it then do it, I'll just disagree to it's benefits. Basically throw in your chromium, barium, lithium, rubidium, thallium, uranium,. etc... :D

Oh and the Synechococcus growth medium (picophytoplankton) that I have been using has chromium (III) nitrate. So that might be another shot.

And yes I put that in the medium because they call for it, I'm not sure it does anything????

Randy Holmes-Farley · Nov 23, 2020

I don’t see any use in debating the meaning of words like “biological role”.

I do not have reason to believe that any form of chromium is actually useful to dose, nor do I know which form might be more useful if you did dose it. I recommended the dominant natural form in seawater, and I doubt there is any problem if it is maintained at natural seawater levels. I do agree it requires more care in handling and one might chose a different form for that reason.

Randy Holmes-Farley · Nov 24, 2020

Note: out of an adundance of caution for aquarist safety from mishandling, I removed the initial chromium recommendation.

Lousybreed · Nov 25, 2020

Wow! I am going to digest this thread, I really appreciate the conversation, and I will respond shortly.

Lousybreed · Nov 27, 2020

Guys, I am note going to add chrome, nor the sodium flouride most likely. I do appreciate the discussion as this has helped me tremendously. I am glad that Randy pointed me in a good route for selenium! That helped out nicely!