Can a silver dollar be used to santize water?

[Elite Engineer]

Say it's the apocalypse, and we need fresh drinking water. Silver is known for its anti-bacterial properties.

 

Would adding a whole silver dollar, to say 1 liter of water able to kill bacteria in it? Just a curious question.

 

~EE

Edited August 1, 2016 by Elite Engineer

[John Cuthber]

If the dollar was red hot and dropped into a relatively small volume of water then yes, it would kill a lot of bugs.

Otherwise, generally, no.

[Sensei]

Microscope view of Silver while touching bacteria

 

This is also worth reading

https://en.wikipedia.org/wiki/Medical_uses_of_silver

 

According to this Silver could make antibiotics thousands times more effective

http://www.nature.com/news/silver-makes-antibiotics-thousands-of-times-more-effective-1.13232

 

But Argyria is not what you would like to have...

https://en.wikipedia.org/wiki/Argyria

(better to have Argyria than die anyway for mortal human, I guess)

Edited August 2, 2016 by Sensei

[Elite Engineer]

If the dollar was red hot and dropped into a relatively small volume of water then yes, it would kill a lot of bugs.

Otherwise, generally, no.

I've heard of stories of settler is the American west, would drop a 1-2 ounce piece if silver in their drinking water to keep it "clean"..

[CharonY]

Ionic silver in solution is what affects bacteria. A big chunk does not release altogether that much of it. In fact, an old oxidized coins is probably more likely to release dirt and germs rather than kill it. I suppose grinding it up could work to some degree.

[DrP]

yea - my first thought also was that there would be germs on the coin.

[StringJunky]

yea - my first thought also was that there would be germs on the coin.

Certain metal objects, like silver and brass, exert an oligodynamic effect on their surface and can inhibit the pathogen populations that live on them. I would imagine you would need a pretty large surface area in contact with water to be useful for sterilising amounts of water, and even then, it's surface would require frequent abrasion to reveal a fresh surface to sterilise. with.

 

It's called the oligodynamic effect. Wikipedia defines the effect as "a toxic effect of metal ions on living cells, algae, molds, spores, fungi,viruses, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations." A study from the National College of Kathmandu in Nepal elaborates:

 

"The exact mechanism of this action is still unknown but some data suggest that the metal ions denature protein of the target cells by binding to reactive groups resulting in their precipitation and inactivation. The high affinity of cellular proteins for the metallic ions results in the death of the cells due to cumulative effects of the ion within the cells (Benson 2002). Similarly, silver inactivates enzymes by binding with sulfhydryl groups to form silver sulfides or sulfhydryl-binding propensity of silver ion disrupts cell membranes, disables proteins and inhibits enzyme activities (Thurman & Gerba 1988; Semikina & Skulacher 1990). The study also suggest that positively charged copper ion distorts the cell wall by bonding to negatively charged goups and allowing the silver ion into the cell (Hambidge 2001). Silver ions bind to DNA, RNA, enzymes and cellular proteins causing cell damage and death."

 

 

That study promotes the use of oligodynamic metals in pots used to hold drinking water, as they tested silver, brass and copper against water containing bacteria like E. coli and Salmonella in small doses. Within 4 hours, the copper pot had killed off the Salmonella microbes, while silver and copper took 8 and 12 hours. "Silver can serve as a disinfectant at concentrations about 1,000 times lower than the toxic level to mammalian life," says the study.

Edited August 3, 2016 by StringJunky

[DrP]

with an old silver coin though you get a patina build up on the surface - I still reckon you could get germs growing on that regardless of the silver in the coin... I could be wrong though, I have not read into it at all.

 

Oligodynamic - new word for me. Thanks.

Edited August 3, 2016 by DrP

[StringJunky]

with an old silver coin though you get a patina build up on the surface - I still reckon you could get germs growing on that regardless of the silver in the coin... I could be wrong though, I have not read into it at all.

 

Oligodynamic - new word for me. Thanks.

Yes, I think I read that they can evolve some resistance. Apparently, brass doorknobs (same action as silver) can keep pathogens down on them within hours and are recommended for public places where many different hands will use the doors. As to the reason for its possible long-term action, I visualise dead skin cells and oils mixing with the metal ions in the brass and eventually forming a very crude germicidal ointment over the doorknob/handle surface simply by people using them; it gets refreshed by manual friction everytime someone uses the handle/knob.

 

A new word for me too.

Edited August 3, 2016 by StringJunky

[CharonY]

There is likely not a lot of active growth on a silver coin (it would be freakishly disgusting if they did), but the antibacterial properties are likely to go down in worn coins and especially when mixed with organic components from handling they may hang on there for quite a bit. Note that putting goo from your hands on it diminishes it (again, as direct contact is necessary).

[Elite Engineer]

From wikipedia: In the presence of atmospheric oxygen, metallic silver can form silver oxides, which have bactericidal properties. Even objects with a solid silver surface (spoons, etc.) have a bactericidal effect.

 

Some my guess is, it doesnt offer some (small) sanitizing effect to the water...probably not in the same capacity as iodine, but at least something.

 

~EE

[CharonY]

Only if it is a pristine coin. Those in circulation (including copper-containing coins) tend to be contaminated to a significant degree (though less than e.g. paper money).