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Isotope Analyses of Hair as a Trace Evidence Tool to Reconstruct Human Movements: Establishing the Effects of the "Human Ecosystem" On Strontium and Oxygen Isotope Ratios

NCJ Number
Date Published
April 2016
92 pages
This project expanded on the researchers' initial work that related hair isotope values (strontium and oxygen) to the isotope ratios of tap water in a given geographic area by examining paired water-hair isotope patterns in six major metropolitan test areas of the Western United States with diverse water management practices.

Many major metropolitan areas within the Western United States acquire their municipal waters from a mix of local groundwater and surface waters as well as waters from distant regions (transported water). The study found that the isotope ratios of tap water corresponded to the stated water source and management practices for discrete areas in a given metropolitan area. As expected, the spatial isotopic heterogeneities observed in the isotope values of tap water across a specific metropolitan area were apparent in the isotope values of human hair, but not as sharply defined as seen in the isotope values of the water. Nonetheless, the istotope values of hair corresponded to the isotope values of water in the overall metropolitan areas. In addition, the study observed seasonal variation in the isotope ratios of tap waters, indicative of changes in water source throughout the sampling interval. This suggests that hair analysis of a given individual compared with isotope analysis of drinking water in various geographic areas can be used to determine that individual's travel history and probable region-of-origin. Critical advances in isotope mass spectrometry technologies, laboratory methodologies, and spatial modeling make possible the increased application of oxygen and strontium isotope analysis of human hair to determine geographic areas where a person has consumed tap water. 46 figures, 18 tables, and 27 references

Date Published: April 1, 2016