

Beverages Leave 'Geographic Signatures' That Can Track People's Movements - cesare
http://www.sciencedaily.com/releases/2010/06/100630132840.htm

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electromagnetic
Congratulations, I went through college drinking Coca Cola imported from
somewhere like Khazakstan because my convenience store was cheap as shit and
they sold it for almost $0.25 cheaper per can.

The Coke-Zero I drank today was made in Toronto. The beer I drank this
afternoon was made in Halifax Nova Scotia. Some of the beer I frequently buy
comes from England, Belgium and I drink wines from Niagara, Australia and
France.

Not to mention a large proportion of the water I get daily comes from my food.
Much of which can come from far of places like Chile and South Africa, and for
my Kiwi's New Zealand.

Yes beverages may leave geographic signatures, but by what I eat and drink in
a single meal I can be receiving water from a half-dozen places around the
world.

~~~
Groxx
_Not to mention a large proportion of the water I get daily comes from my
food. Much of which can come from far of places like Chile and South Africa,
and for my Kiwi's New Zealand._

 _Very_ good point, I hadn't considered that source until I read this comment.
Given that they're measuring the ratio of the isotopes, this kind of
"pollution" could probably cause significant noise in any sample. I wouldn't
be surprised it it were enough to make pinpointing nearly impossible for many
people.

It'd be interesting to see an _actual_ study of a few hundred people, and see
how accurately it can pinpoint travelers (and their destinations) as opposed
to global-munchers.

~~~
electromagnetic
If you're a fruit-eater the noise would be incredibly high. Think of
watermelon, oranges, grapefruits, heck even tomatoes are all frequently eaten
by people and contain large amounts of water.

Someone who eats 'healthily' is going to be much harder to geolocate than
someone who eats 'carnivore' style.

I suppose you would look for the strongest source and use that. However I
can't help but feel that they're measuring differences in identical isotopes
and not relying on unique isotopes (IE of a different mineral) to do the
locating. More potassium might mean the North American east coast and more
calcium could mean the west is how their method reads to me. This means that
they're calculating from the sum of the isotopes.

~~~
Groxx
The article mentions using only hydrogen and oxygen isotopes (I'd assume due
to the distortion caused by filtering if you did it by any other elements),
and looking at hair samples to detect the isotopes in the proteins / molecules
which make it up. Even being carnivorous is going to distort things if you get
your meat from multiple locations (say, fish. That comes from _everywhere_ ,
at least for me), as you'll incorporate the amino acids (which have plenty of
H and O) into your own proteins.

After looking closer, it appears that the study makes _only_ the (obvious)
claim that bottled water purchased _near_ location A has similar isotopes to
water _in_ location A, due to bottling habits. Though I haven't read the study
itself. The article _may_ be entirely vague speculation, to drum it up into
something more exciting / inflammatory.

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ryanwaggoner
Cool idea, but what practical use does this have?

~~~
btilly
The hope is that if it became good enough, it could be used for forensic
evidence. For instance if hair is discovered at a murder scene, you could get
evidence about where the murderer likely lives.

~~~
anigbrowl
That seems like a bolt-on statement to me, included to suggest some
possibility of future funding/social good in order to justify a grant or other
government funding being used to finance this research.

Scientifically, it's fair enough - hair testing can be used to detect drug
use, for example. But people generally drink many different kinds of liquid
per day, and only the most consistent and unusual intake patterns would be
much actual use. Great for CSI-style plots like 'it's said he will only drink
wine made in the village where he grew up...start staking out high-end
barbershops.' If you're trying to match a hair found at a crime scene to a
particular suspect, you just compare his DNA with that at the root of the hair
sample.

