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.
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.
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.
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.
Assuming it worked as advertised (see electromagnetic's comment for thoughts to the contrary), what use wouldn't there be for a way to track people, especially one as unobtrusive as this? Not useful for the average person, but for any covert study of someone it could be handy.
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.
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.
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.