Stories tagged isotopes


Chop it off and send it in!
Chop it off and send it in!Courtesy miss pupik
A couple weeks ago I posted a link to a project in which Dr. Patrick Wheatley was soliciting donations of hair for geochemical research. Intrigued, I contacted Patrick to ask him more about the hair project.

Me: What do you look for as you test the hair?

Patrick: I'm looking for changes in the ratios of isotopes in various elements. I hope to tie the changes in isotopic ratios to differences in geography, either through differences in the isotope ratios of local water supplies or fundamental deferences in the geology of the region where the hair was grown.

Me: How do those isotopes get in our hair in the first place?

Patrick: They are incorporated through our drinking water or diet.

Me: What will your findings help scientists do or understand? Is there a practical application for this research?

Patrick: This research is driven by a possible forensic application, knowing the past whereabouts of victims of crimes (perhaps dead and unable to talk about where they were or perhaps held in a secret location) or suspects of crimes (maybe unwilling to talk about where they have spent time recently). There are also possible medical applications.

You can still send hair in for the project. More information can be found at the project's website.

Scientists at the University of Utah have discovered a way to read the water molecules in a person’s hair, and thereby determine where that person comes from. Hydrogen and oxygen atoms come in different forms, or isotopes, which are found in different parts of the country. As your body grows hair, it uses the isotopes it absorbed from your local drinking water. Reading the isotopes tells scientists where the person lived. This tool can be used to help identify bodies and solve missing persons cases.


Nipping crime in the bud: When asked whether or not this method could be used to find the source of other illegal drugs, the Alaskan scientist stated, "Um... What?"  (photo by ilmungo)
Nipping crime in the bud: When asked whether or not this method could be used to find the source of other illegal drugs, the Alaskan scientist stated, "Um... What?"
(photo by ilmungo)

Sometimes I place quotation “marks” randomly. It’s a kind of written-language Tourette’s Syndrome, and I live in constant fear that its effects might “lead” people to false conclusions. “”

Anyhow, scientists at the University of Alaska Fairbanks are developing methods of tracing samples of marijuana back to their points of origin by studying the “isotopic fingerprint” of the plants. Presumably this is to aid people suffering from the advanced stages glaucoma find their medicine.

Whatever the reason for it might be, the process for determining the growing location of the drug is an interesting one. Isotopes, for those of you who are still reading, are, of course, elements with the same number of protons and electrons, but different numbers of neutrons. For example, the element nitrogen can be found with 13 neutrons, 14 neutrons, or 15 neutrons – those are all isotopes of nitrogen.

When you look at the ratio of isotopes in an object, you can sometimes find out where that object came from geographically, because certain areas will sometimes have isotopic signatures. This is how scientists figured out where Otzi the Iceman came from: the enamel on his teeth had an isotopic match with a small region in Italy, so it’s very likely he grew up there.

Applying this basic method to marijuana, the Alaskan scientists are finding that isotopic levels of hydrogen and oxygen in the plants can show where the water they were fed with came from. Carbon in the plant can show whether or not it was grown indoors. Nitrogen isotope levels can also be used to learn about plants’ origins. Combining the information from all of these ratios, researchers are attempting to construct a map of marijuana isotopic signatures, so that any sample with unknown origins could be matched up with a specific location.

In order to achieve this isotope map, however, the project director says he needs “time, money and many more samples of marijuana.”

Science takes back the streets!