Hair Reveals Where Murder Victims Drank Water

The two maps here show predicted average hydrogen (top) and oxygen (bottom) isotope levels in human hair across the continental United States -- isotopes that vary with geography because of different isotope levels in local drinking water. The ratios of heavy, rare hydrogen-2 to lighter, common hydrogen -1 are highest in red and orange areas in the top map, and lowest in the blue and darker green areas. The ratios of heavy, rare oxygen-18 to lighter, common oxygen-16 are highest in red and orange areas of the bottom map, and lowest in the blue and darker green areas. Photo Credit: The University of Utah