October 3, 2011
Cold Case Files; Forging Forensic Isoscapes
Law enforcement may have a new crime-solving tool, courtesy of geoscientists. About five years ago, scientists coined the word "isoscape" to describe a new kind of map: a spatial distribution of stable isotope ratios (from elements such as carbon, hydrogen, oxygen, nitrogen and strontium) in different parts of the world, based on known ways that these isotopes behave in the environment. Different isotopes tell different stories – carbon can help identify diet, whereas hydrogen and oxygen can help identify provenance (for example, about 30 percent of the hydrogen deposited in a human hair comes from the water or water-based beverages the person drank) – so the combination of different isotopic values into one map creates a far more powerful tool than a map based on any single element.
As EARTH explores in "Cold Case Files: Forging Forensic Isoscapes," the potential usefulness of isoscapes is wide-ranging and thrilling: By measuring the isotopic ratios in anything from bones to hair to plants to gems, and then comparing those values (perhaps even changing over time, as bones, plants and teeth grow) with an isoscape, it might be possible to track human geographic origins, identify the source of illicit drugs, detect counterfeit food products and follow the migration of wildlife.
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