# The Naked Scientists Forum

### Author Topic: 3000 years of filtration !..that's nice !...but how can they tell ?  (Read 7087 times)

#### neilep

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« on: 18/12/2007 22:35:15 »
Dear Filtrationologists,

Recently I enjoyed a bottle of mineral water in a restaurant.

As an avid reader of mineral water labels I could not help but be impressed by this statement...

"Every drop of has been naturally filtered through water bearing white sandstone for at least 3000 years".

Now c'mon ?...How can they measure this ?...how can they prove it ?

I want to kn'eau' !!

#### lightarrow

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #1 on: 18/12/2007 22:46:25 »
Dear Filtrationologists,

Recently I enjoyed a bottle of mineral water in a restaurant.

As an avid reader of mineral water labels I could not help but be impressed by this statement...

"Every drop of has been naturally filtered through water bearing white sandstone for at least 3000 years".

Now c'mon ?...How can they measure this ?...how can they prove it ?
Wel, you take a cronometer and...
Anyway, making a simple theorical computation, if that water takes, e.g., one day to go through 33.3 centimeters of that soil and it has to pass through 365 kilometers of it, it would be a total of 3000 y.
« Last Edit: 18/12/2007 22:53:50 by lightarrow »

#### another_someone

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #2 on: 18/12/2007 22:59:56 »
You expect them to prove what's on the label?  The only proof marketing men need is whether it sells more bottles.

In reality, they cannot prove anything, but they can say if they can show the water travels down through the rock for 20cm in a year, then in 3,000 years you might guess it may travel down 600 metres.  They should be making adjustments for the different types of rock the water will encounter in the 3,000 year journey, but aside from that, it is pure guesswork.  It is merely extrapolating an average on a shorter time - but as to whether it applies to every drop is another matter.

#### Bass

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #3 on: 19/12/2007 00:38:21 »
Water can be age dated using carbon 14 or hydrogen isotopes.

Neil, does your bottled water glow in the dark??

#### another_someone

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #4 on: 19/12/2007 01:17:43 »
Water can be age dated using carbon 14 or hydrogen isotopes.

It did occur to me that this might be the case, but would you rely on that for water that has been filtered through rocks?

The whole point of filtration is to change the constitution of the water, which both means taking some chemicals (potentially, some isotopes preferentially to others) out of the water; but also potentially adding matter from the rocks into the water.  Can you be sure that the impurities in the water at the bottom of the rocks are predictably related to the impurities in the water at the top of the rocks?

#### paul.fr

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #5 on: 19/12/2007 01:39:37 »
...but as to whether it applies to every drop is another matter.

This is a good point George. If the bottling place/factory washes out the bottles prior to filling then surely they use "standard" tapped or piped water for that purpose.

If that is the case, then surely some of that water must get retained in the bottle.

#### Bass

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #6 on: 19/12/2007 05:02:00 »
It did occur to me that this might be the case, but would you rely on that for water that has been filtered through rocks?

Carbon 14 has a relatively short half life (around 5700 years)- so there should be no carbon 14 left in the rocks that the water filters through.  Possible that some carbon 14 from water will exchange with carbon 12 in rocks, but this should be minor.  Any carbon 14 in the water will be there from the original rainwater- so works well for dating purposes for up to 10,000 years of so.

#### another_someone

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #7 on: 19/12/2007 07:23:09 »
Carbon 14 has a relatively short half life (around 5700 years)- so there should be no carbon 14 left in the rocks that the water filters through.  Possible that some carbon 14 from water will exchange with carbon 12 in rocks, but this should be minor.  Any carbon 14 in the water will be there from the original rainwater- so works well for dating purposes for up to 10,000 years of so.

Not totally convinced about this.  It is after all the soil and rocks of a particular locality that give the water its distinctive regional flavour, so clearly there must be minerals leaching from the rocks into the water, and these must influence any tests you make on the rocks.

#### neilep

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #8 on: 19/12/2007 14:32:11 »

Thank you Light Arrow, Another_Someone, Bass (Wow !!...glow in the dark mineral water !!..hmmmmm....I wonder if there's a business opportunity there....could one make water glow in the dark safely ?)...thank you Paul

I did wonder if they just took the speed of descent but surely there must be any number of obstacles and changes of incline etc etc......

Carbon dating water ?...oh my !!.......I assume then that the age of the water before it starts the filtration process has no effect on the calculation ?

#### Bored chemist

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #9 on: 19/12/2007 18:02:23 »
Could someone let me know how you carbon date something with no carbon in it?

#### another_someone

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #10 on: 19/12/2007 18:17:45 »
Could someone let me know how you carbon date something with no carbon in it?

I don't think it right to say that water has no carbon it it - most water has some carbonate ions dissolved it it.  The problem is that carbonate ions are not normally directly derived from living organisms, thus, 14C will only tell you when the carbon was breather by a living organism, which could have been long before it entered the water.

#### Bored chemist

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #11 on: 19/12/2007 18:24:28 »
H2O
Where's the C?
Anyway, even the dissolved CO2 would useless as a way to date the stuff as it would have exchanged with (ancient) carbopnate minerals on the way through.

#### Bass

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #12 on: 19/12/2007 19:01:14 »
Reference to 14C dating of groundwater from http://filebox.vt.edu/users/mstrader/carbon.html

"Carbon-14 (14C) ... is continuously being produced in the atmosphere.  This process occurs from cosmic ray bombardment of nitrogen nuclei...Since Carbon-14 has a half-life of 5,730 years, 14C is useful when dating ground waters that are between 1,000 and 30,000 years old.  A geochemical reaction path model design by Plummer must be used to account for the dilution and addition of carbon along ground water flow paths.  Using the model greatly enhances accuracy when assigning ages to ground waters."

#### Bass

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #13 on: 20/12/2007 06:10:00 »
Rainwater (and clouds) react with CO2 in the atmosphere to produce carbonic acid- which is why most rainwater is slightly acidic.

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #14 on: 25/05/2009 05:06:33 »
Dear Filtrationologists,

Recently I enjoyed a bottle of mineral water in a restaurant.

As an avid reader of mineral water labels I could not help but be impressed by this statement...

"Every drop of has been naturally filtered through water bearing white sandstone for at least 3000 years".

Now c'mon ?...How can they measure this ?...how can they prove it ?
Wel, you take a cronometer and...
Anyway, making a simple theorical computation, if that water takes, e.g., one day to go through 33.3 centimeters of that soil and it has to pass through 365 kilometers of it, it would be a total of 3000 y.
I will do what have you said.. I just wanna say thank you for sharing this information to us. Hoping that this will not be the last post that I could be read written by you.

« Last Edit: 25/05/2009 10:23:37 by BenV »

#### lightarrow

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #15 on: 25/05/2009 16:50:00 »
I will do what have you said.. I just wanna say thank you for sharing this information to us. Hoping that this will not be the last post that I could be read written by you.
Thank you, you are too kind for so little...

#### Andrew K Fletcher

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #16 on: 25/05/2009 18:24:13 »

Ask neil if it was carbonated water :)
Could someone let me know how you carbon date something with no carbon in it?

I don't think it right to say that water has no carbon it it - most water has some carbonate ions dissolved it it.  The problem is that carbonate ions are not normally directly derived from living organisms, thus, 14C will only tell you when the carbon was breather by a living organism, which could have been long before it entered the water.

#### Bored chemist

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##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #17 on: 26/05/2009 10:22:18 »

Ask neil if it was carbonated water :)
Could someone let me know how you carbon date something with no carbon in it?

I don't think it right to say that water has no carbon it it - most water has some carbonate ions dissolved it it.  The problem is that carbonate ions are not normally directly derived from living organisms, thus, 14C will only tell you when the carbon was breather by a living organism, which could have been long before it entered the water.

If it was carbonated then it might have been artificially carbonated since it left the aquifer in which case the age of the carbon is meaningless.
If it was naturally carbonated then that carbon may have had an oportunity to equilibrate with ancient carbonates on the way through and if it's not carbonated then there's no carbon to date.

What answer could Neil give to the question of carbonation that would help answer the debate about the stuff's age?

#### The Naked Scientists Forum

##### 3000 years of filtration !..that's nice !...but how can they tell ?
« Reply #17 on: 26/05/2009 10:22:18 »