Reply
 
Thread Tools Display Modes
  #1  
Old 10-24-2011, 09:56 AM
aceplace57 aceplace57 is online now
Guest
 
Join Date: Oct 2009
Location: CentralArkansas
Posts: 24,362
ultra-pure water (UPW) - Water too clean to drink?

This would make a good Jeopardy question.

I've worked around electronics all my adult life. I'd never heard of UPW. It makes sense when you think of minerals in water as "boulders" that would contaminate the chips.

I've heard of heavy water used in Nuclear research. I wonder how it compares to UPW?

Quote:
the electronic pathways on microchips are now so fine they can’t be seen even with ordinary microscopes. The pathways are narrower than the wavelengths of visible light. They can only be seen with electron microscopes. And so even the absolute tiniest of debris can be like a boulder on a semiconductor--so the chips have to be washed, but with water that is itself absolutely clean.

The water must have nothing in it except water molecules--not only no specks of dirt or random ions, no salts or minerals, it can’t have any particles of any kind, not even minuscule parts of cells or viruses.
<snip>
It’s also why it’s not safe to drink. A single glass of UPW wouldn’t hurt you. But even that one glass of water would instantly start leeching valuable minerals back out of your body.
http://www.fastcompany.com/1750612/t...ke-your-iphone

Last edited by aceplace57; 10-24-2011 at 09:58 AM.
  #2  
Old 10-24-2011, 09:59 AM
Nava Nava is online now
Guest
 
Join Date: Nov 2004
Location: Hey! I'm located! WOOOOW!
Posts: 39,692
The heavy water is similarly pure, but has a higher concentration of heavy isotopes. Actually, water like that is used in many industries (Pharma is a big one).
  #3  
Old 10-24-2011, 10:33 AM
Hampshire Hampshire is offline
Member
 
Join Date: Jan 2003
Location: Minneapolis
Posts: 10,759
Is it much different than distilled water?
  #4  
Old 10-24-2011, 10:34 AM
Nava Nava is online now
Guest
 
Join Date: Nov 2004
Location: Hey! I'm located! WOOOOW!
Posts: 39,692
Distilled water may contain organics.

Nowadays using cartridge-based purification systems is more common than distilling water, both because they're generally easier to deal with and because if you want to make sure you don't have organics you'd need to put your distilled water through cartridges anyway. Their basic structure includes some active-carbon (or similar stuff, like diatomiaces) cartridges to get rid of organics and largeish particles, plus two types of ion-exchange cartridges to get rid of any salts.

Last edited by Nava; 10-24-2011 at 10:36 AM.
  #5  
Old 10-24-2011, 10:43 AM
Mtgman Mtgman is offline
Guest
 
Join Date: Jul 2001
Location: Searching for Tanelorn
Posts: 6,192
The major thing that makes this unsafe to drink is shared with another type of purified water, deionized water. Water, being highly polarized, tends to form natural ionic bonds with lots of different substances. Sodium is one of the most common, as is calcium, and in modern plumbing, Iron and Copper. Without these ions water is pure hydric acid (IUPAC - Oxidane), and that's the best way to think about it. It's pretty nasty stuff when you put it into a human system. Fortunately it's not likely to get into the human system in any appreciable quantities. The characteristic taste of "water" is actually given to it by the common ions which it forms. Without these ions, water tastes bad. Bitter and slightly caustic. You're not likely to make it through a full glass of the stuff.

Enjoy,
Steven
  #6  
Old 10-24-2011, 10:47 AM
Der Trihs's Avatar
Der Trihs Der Trihs is offline
Guest
 
Join Date: Aug 2005
Location: California
Posts: 38,616
Quote:
Originally Posted by aceplace57 View Post
I've heard of heavy water used in Nuclear research. I wonder how it compares to UPW?
Not very similar. This UPW is ordinary if extremely pure water. Heavy water isn't ordinary water. In fact logically if there was a use for it there's no reason why you couldn't have "UPHW", Ultra Pure Heavy Water.

Heavy water is unhealthy to drink, but not because it leeches minerals; heavy water is unhealthy in itself (assuming you were dumb enough to drink enough for long enough).
  #7  
Old 10-24-2011, 12:06 PM
lazybratsche lazybratsche is offline
Guest
 
Join Date: Feb 2006
Posts: 3,722
Quote:
Originally Posted by Mtgman View Post
The major thing that makes this unsafe to drink is shared with another type of purified water, deionized water. Water, being highly polarized, tends to form natural ionic bonds with lots of different substances. Sodium is one of the most common, as is calcium, and in modern plumbing, Iron and Copper. Without these ions water is pure hydric acid (IUPAC - Oxidane), and that's the best way to think about it. It's pretty nasty stuff when you put it into a human system. Fortunately it's not likely to get into the human system in any appreciable quantities. The characteristic taste of "water" is actually given to it by the common ions which it forms. Without these ions, water tastes bad. Bitter and slightly caustic. You're not likely to make it through a full glass of the stuff.

Enjoy,
Steven
Do you have any cite that ultrapure water is unhealthy? I've drank some ultrapure water before (deionised water further filtered to 18.2 Mohm, with a 22 micron filter, for whatever it's worth). It was a bit sour but hardly as nasty as you make it out to be. Carbonated water is far more sour and acidic, IMO. I can't conceive that ultrapure water would cause any significant "leaching" from the body.

In fact, the link you provided calls the claims of dangers "pure nonsense".

Last edited by lazybratsche; 10-24-2011 at 12:06 PM.
  #8  
Old 10-24-2011, 12:26 PM
JimboJamesJimmersonIII,Esq. JimboJamesJimmersonIII,Esq. is offline
Guest
 
Join Date: Sep 2010
Posts: 31
I don't want to derail your question regarding heavy water, but the notion that ultrapure (or deionized) water is unsafe to drink is false.

Quote:
It’s also why it’s not safe to drink. A single glass of UPW wouldn’t hurt you. But even that one glass of water would instantly start leaching valuable minerals back out of your body.
Statements like this are floating all over the internet and repeated in many laboratories. I can only attribute its basis to a poorly designed thought experiment. "Valuable minerals" leech out of the body? To where?

In theory and in practice, yes, ions will diffuse from high concentrations to areas of low concentrations. So if you take pure water, devoid of all ions, and introduce it to your mouth and gut, the ionic concentration of all contacted fluids will decrease. This does not mean it is dangerous, or even problematic. The water you drink from the tap also has a much lower ionic concentration than any of your bodily fluids. Not a big deal. For the most part, any water that is introduced to your gut is absorbed into the blood stream. Any excess is expelled by your kidneys. So even if deionized water pulled, via osmotic forces and/or diffusion, ions from your body, they would just be reabsorbed. Net loss of "valuable minerals" is zero.

To make deionized water dangerous, you would have to drink massive quantities, quantities that would lead to water intoxication (which would occur at said quantities whether it was deionized or not).

I personally have drank dozens (possibly hundreds) of gallons of 18 mega-ohm, deionized water. In my old lab, the DI system was more easily accessible than the water fountains, so I'd drink a pint or two a day.

Quote:
Originally Posted by Mtgman View Post
Without these ions, water tastes bad. Bitter and slightly caustic. You're not likely to make it through a full glass of the stuff.
DI water does taste different, much in the way bottled water tastes different from tap water. I personally wouldn't call it bitter, but it doesn't taste as good as most bottled water. It was certainly better than the tap water in our building.

Dangerous? No. One could make try to make the argument that it could be bad for your teeth because it could leach calcium from them. However, I would be very surprised if it was more damaging than acidic beverages like soda or orange juice.

As for health effects of residual ion exchange resin in DI water, I'll take my chances. The amount of resin present in DI water is trivial anyway.

I apologize if this is seen as a highjack, but seeing as your OP was based partly on incorrect information, I felt it was appropriate to address this.

On edit: I see lazybratsche addressed similar points. Also, my spelling errors.

Last edited by JimboJamesJimmersonIII,Esq.; 10-24-2011 at 12:29 PM.
  #9  
Old 10-25-2011, 11:37 PM
Taomist Taomist is offline
Guest
 
Join Date: Jul 2009
Location: N.O.T. Land!
Posts: 6,061
I used to work in a clean-room for a micro-chip company. Of COURSE I tasted the water; how can you not?! But it's not like I drank a big glass of it. I hate water, blech.
  #10  
Old 10-26-2011, 09:47 AM
GaryM's Avatar
GaryM GaryM is offline
Charter Member
 
Join Date: Jun 2000
Location: St. Louis, MO 50mi. West
Posts: 4,891
Hungry Water discussion on Car Talk
  #11  
Old 10-27-2011, 03:41 PM
lazybratsche lazybratsche is offline
Guest
 
Join Date: Feb 2006
Posts: 3,722
Perhaps this might have more responses in GQ? I'll report it for change.

But I'll also keep giving my WAG moderately educated opinion . Which means that I should say that I'm no chemist, but I've picked up a working knowledge of aqueous chemistry as a biologist.

My guess is that the "hungry water" idea is technically true but absolutely trivial in most real-world situations.

For the sake of consideration, we can look at total dissolved solids (TDS), a common measure of water purity. That includes all of the ions, but also other stuff that I'm going to ignore. Tap water has TDS in the few hundred ppm range. There are natural sources with TDS in the tens of ppm; think extremely clean mountain spring. Ultra-pure water has TDS in the few ppb range, which is almost entirely non-ionic (usually some sort of organic carbon). Let's just round that down to zero. So, oversimplifying, we can think that the "hungry" ultrapure water will corrode ("eat") from every surface until it reaches some equilibrium. As a ballpark, I'll assume that equilibrium is in the tens of PPM, which is the ballpark of "very clean".

In the car radiator example, the "hungry" water would then dissolve some amount of the metals until it reaches that equilibrium. With a coolant volume of a few liters, the dissolved amount would be tens of milligrams. And that's tiny, compared to the many kilograms of car radiator. But of course, you don't put ultrapure water in a radiator by itself, you mix it with coolant. And that coolant has lots and lots of stuff in it (ethylene glycol, various corrosion inhibitors like silicates or phosphates), probably having a hell of a lot more than tens of ppm of dissolved ions. The presence or absence of a few ppm of dissolved ions in water would be absolutely insignificant once you make your 50:50 mixture.

Same goes in your body. Your saliva has lots of protein and salts. Your stomach is full of ions, with something like 5000 ppm just of hydrochloric acid. Once the ultrapure water mixes into the bag of brine and goo that is your digestive tract, it won't be capable of leaching anything at all.

I can imagine that there may be examples where it's worth considering the extra corrosion caused by ultrapure water -- say, a large industrial plant that handles huge quantities of the stuff. But it shouldn't make a damn bit of difference in ordinary circumstances.

Last edited by lazybratsche; 10-27-2011 at 03:46 PM.
  #12  
Old 10-27-2011, 03:45 PM
twickster twickster is offline
Charter Member
Charter Member
 
Join Date: Aug 2002
Location: Philadelphia
Posts: 38,721
Moved MPSIMS --> GQ.
  #13  
Old 10-27-2011, 05:02 PM
HMS Irruncible HMS Irruncible is online now
Guest
 
Join Date: Nov 2004
Posts: 7,406
Quote:
Originally Posted by Mtgman View Post
Without these ions water is pure hydric acid (IUPAC - Oxidane), and that's the best way to think about it.
False.
Quote:
It's pretty nasty stuff when you put it into a human system.
False.

Quote:
Without these ions, water tastes bad. Bitter and slightly caustic. You're not likely to make it through a full glass of the stuff.
Complete horseshit. I've drunk deionized water (sanitized by boiling, for reasons described below) and had no problem with it.

For the record, the reason you shouldn't assume that deionized water is safe is that it may be contaminated with bacteria. Most demineralization methods do not remove bacteria. If they do remove bacteria, they also remove all the chemicals that prevent bacteria from growing later.

Last edited by HMS Irruncible; 10-27-2011 at 05:04 PM.
  #14  
Old 10-27-2011, 05:09 PM
Ogre Ogre is offline
Guest
 
Join Date: Jul 2000
Location: Bama
Posts: 10,747
As others have said, no. Ultrapure water is harmless. I've drank quite a lot of it from reagent-grade water filtration systems and DI carboys over the last 20 years. No effects. Besides, even if it *did* leach minerals out of your tissues (IOW, disrupt osmoregulation at a cellular level, which it wouldn't, because cellular osmoregulatory processes frequently go against concentration gradients), the minerals would get reclaimed in the kidneys anyway.

Last edited by Ogre; 10-27-2011 at 05:09 PM.
  #15  
Old 10-27-2011, 05:19 PM
Smashed Ice Cream Smashed Ice Cream is offline
Guest
 
Join Date: Sep 2001
Location: Portland, OR
Posts: 619
The theory of not drinking DI or superduper pure water is based on osmosis, but like lots of people have pointed out, a little isn't going to do much. But don't make it your only water intake full time... we need the ions.

"Heavy water" is water molecules with the kinda-fake formula of D2O instead of H2O. Hydrogen as we think of it, contains one proton and one electron. Deuterium atoms contain one proton, one neutron, and one electron. (An element is defined by the number of protons, and varying numbers of neutrons are simply isotopes of the same element.) Tritium would have one proton, two neutrons, and one electron and be really heavy water.

As far as I can imagine, there would be no difference in drinking H2O or D2O, although it would weigh a LOT more. It might feel funny. I have access to it at work, so I'll ask around and see if anyone has tried it. I'm sure someone has!
  #16  
Old 10-27-2011, 05:19 PM
jk1245 jk1245 is offline
Guest
 
Join Date: Jul 2000
Location: Madison, WI
Posts: 2,114
I work in the biopharmaceutical area (we manufacture biologics for use in human clinical trials) and thus we use lots of water for injection (wfi) both in the formulation of the drug products and in cleaning of product contact equipment.

It is widely known within the industry that wfi is corrosive due to its extreme purity. Any stainless steel tanks, pipes or fittings will corrode if left in contact with wfi. This might be where the story comes from, although the corrosion is gradual over time, someone may have connected "corrosive" with "acid" and come up with the story. WFI is not harmful to drink, which makes sense since it is also not harmful to inject it directly into your body.

Last edited by jk1245; 10-27-2011 at 05:20 PM.
  #17  
Old 10-27-2011, 05:30 PM
Derleth Derleth is online now
Guest
 
Join Date: Apr 2000
Location: Missoula, Montana, USA
Posts: 20,786
Speaking of heavy water, does anyone make T₂O with tritium? I realize it would be radioactive, but that doesn't usually stop us.
  #18  
Old 10-27-2011, 07:32 PM
DHMO DHMO is offline
Guest
 
Join Date: Oct 2009
Location: Rocky Mountains
Posts: 284
Quote:
Originally Posted by Mtgman View Post
The major thing that makes this unsafe to drink is shared with another type of purified water, deionized water. Water, being highly polarized, tends to form natural ionic bonds with lots of different substances. Sodium is one of the most common, as is calcium, and in modern plumbing, Iron and Copper. Without these ions water is pure hydric acid (IUPAC - Oxidane)
<snip>
Without these ions, water tastes bad. Bitter and slightly caustic. You're not likely to make it through a full glass of the stuff.
[emphasis added—DHMO]

As a Water Industry professional with 18 years' experience in the field, I would like to comment on the common mis-perception highlighted above. Absolutely pure water (i.e., containing nothing but H2O molecules) has a natural tendency to dissociate into Hydrogen ions (H+) and Hydroxyl ions (OH-) The extent to which this reaction proceeds is measured by the "power of Hydrogen ion concentration", or pH.

The precise definition of pH is somewhat complex, and the specific parameters I describe will be slightly vague. The number assigned to the pH scale is the inverse negative logarithm (base 10) of the ionic concentration (mol/L). What this means is that neutral water, which freely dissociates into Hydrogen+ and Hydroxyl- ions at 1 × 10-7 moles per Liter (mol/L) is given a pH of "7" [log10(10-7)] = -7; the inverse would be +7. Since there are as many H ions as there are OH ions, the water is neither "Acidic" nor "Basic". Alternatively, depending on the exact chemistry, it may be just as correctly described as "slightly acidic" or "slightly basic".

Anything with a pH below 7 is considered "Acidic," with lower numbers signifying stronger acidic action. A pH above 7 is "Basic," and higher numbers indicating stronger caustic action. "Acid" is the fundamental opposite of "Caustic." Most aqueous solutions derive their acid or caustic nature from the (usually) ionic substances dissolved in them. The higher the concentration of dissolved substance causing the solution to be acidic, for example, the stronger the acid, and the lower the pH.

To say that water with no dissolved ions could be described as "pure hydric acid" is ridiculous. If it were, in fact, "acid", it could not taste "caustic."

There is a related quality to water, called "stability." Regardless of the pH of the sample, the water may be "scale-forming" or "aggressive," depending on the concentration and species of ions dissolved. This might be the source of confusion regarding pure water "leaching" "valuable minerals" out of your body.

The only thing our bodies require from water we ingest is H2O molecules. The concentration of dissolved ions in our digestive system is so great (gastric acid has a pH of 1 to 2, about 5000ppm HCl, and large quantities of potassium chloride (KCl) and sodium chloride (NaCl)) that each gulp of pure water will only serve to dilute the enormous concentration to a slightly lower level. At no time will there be a point where pure water exists on one side of a cellular membrane, osmotically "leaching" minerals out of the cell through the membrane. In fact, osmosis would work in precisely the opposite direction—that is, water would be forced into the cell, in an attempt to equilibrate the ionic concentration on both sides of the membrane.
  #19  
Old 10-27-2011, 07:43 PM
Crafter_Man's Avatar
Crafter_Man Crafter_Man is offline
Guest
 
Join Date: Apr 1999
Location: Ohio
Posts: 11,048
And to complicate it even further, there's the whole issue of the isotopic composition of water.

The water triple point temperature standard, for example, contains very very pure water. But it also has an isotopic composition defined by VSMOW.
  #20  
Old 10-27-2011, 08:07 PM
ZenBeam ZenBeam is offline
Guest
 
Join Date: Oct 1999
Location: I'm right here!
Posts: 8,858
Quote:
Originally Posted by Smashed Ice Cream View Post
As far as I can imagine, there would be no difference in drinking H2O or D2O, although it would weigh a LOT more. It might feel funny. I have access to it at work, so I'll ask around and see if anyone has tried it. I'm sure someone has!
The relative difference in mass between H and D is large enough that it affects reaction rates somewhat. Enough that drinking too much D2O can kill you.

From the Wikipedia page:
Quote:
However, the difference (especially the biological properties) is larger than in most other isotope-substituted compounds because deuterium is unique among heavy stable isotopes in being twice as heavy as the lightest isotope. This difference increases the strength of water's hydrogen-oxygen bond, and this in turn is enough to cause differences that are important to some biochemical reactions.

The human body naturally contains deuterium equivalent to five grams of heavy water, which is thought to be harmless. Similar doses are used as non-radioactive tracers in human and animal metabolic experiments. However, in animal studies when heavy water replaces ~25% to 50% of the body's water, it interferes with cellular mitotic apparatus and prevents cell division.[2] Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (which in turn is 70% of body weight) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard.
  #21  
Old 10-27-2011, 08:28 PM
HMS Irruncible HMS Irruncible is online now
Guest
 
Join Date: Nov 2004
Posts: 7,406
Quote:
Originally Posted by jk1245 View Post
It is widely known within the industry that wfi is corrosive due to its extreme purity.
I cannot possibly see any chemical reason this would be true. If it is "widely known" then it wouldn't be too much trouble for you to dig up a source, right?

I mean, yes, if water has sodium, chloride, calcium, then it will less aggressively pick up sodium, chloride, and calcium. But that doesn't have anything to do with whether it will bind iron or not. In fact the increased electrical conductivity should make it more corrosive to metal, not less.
  #22  
Old 10-27-2011, 09:02 PM
lazybratsche lazybratsche is offline
Guest
 
Join Date: Feb 2006
Posts: 3,722
Now that there are more authoritative people on this, I'll throw out my "everyone knows x" for verification.

The water that normally comes out of the lab purification systems I'm familiar with is usually slightly acidic, pH 6 (plus or minus a bit). That much I've measured myself. I've heard this explained as the water being so unbuffered that the pH is determined by dissolved CO2 forming carbonic acid. Is this plausible?
  #23  
Old 10-27-2011, 09:12 PM
HMS Irruncible HMS Irruncible is online now
Guest
 
Join Date: Nov 2004
Posts: 7,406
Quote:
Originally Posted by lazybratsche View Post
Now that there are more authoritative people on this, I'll throw out my "everyone knows x" for verification.

The water that normally comes out of the lab purification systems I'm familiar with is usually slightly acidic, pH 6 (plus or minus a bit). That much I've measured myself. I've heard this explained as the water being so unbuffered that the pH is determined by dissolved CO2 forming carbonic acid. Is this plausible?
The mechanism is quite real although not necessarily limited to purified water. Even tap water can acidify from CO2 absorption, though obviously it depends on the concentration and species of ion present.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 12:03 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright © 2018 STM Reader, LLC.

 
Copyright © 2017