U.S. flag

An official website of the United States government, Department of Justice.

Strontium isotope ratios of human hair from the United States Patterns and aberrations

NCJ Number
254076
Date Published
2019
Length
12 pages
Author(s)
B. J. Tipple; et al
Agencies
NIJ-Sponsored
Annotation
This article examines the use of strontium isotope ratios of hair as a tool to estimate human provenance.
Abstract
Strontium isotope ratios of hair may be a valuable tool to estimate human provenance. However, the systematics and mechanisms controlling spatial variation in Sr-87Sr-86 of modern human hair remain unclear. Here, the authors measure Sr-87Sr-86 of hair specimens from across the USA to assess the presence of geospatial relationships. Ninety-eight human hair specimens were collected from salon/barbershop floors in 48 municipalities throughout the conterminous USA. Sr and Sr-87Sr-86 ratios were measured from hair using quadrupole and multi-collector inductively coupled plasma mass spectrometers, respectively. The Sr and Sr-87Sr-86 ratios of hair were compared with the measured Sr and Sr-87Sr-86 ratios of tap waters from the collection locations. In addition, the Sr-87Sr-86 ratio of hair was compared with the modeled ratios of bedrock and surface waters. Hair color was independent of the Sr-87Sr-86 ratio, but related to Sr. The Sr-87Sr-86 ratios of hair and leachate were not statistically different and were positively correlated; however, in several hair-leachate pairs, the ratios were conspicuously different. The Sr-87Sr-86 ratios of both hair and leachate were linearly correlated with tap water. The Sr-87Sr-86 ratio of hair was also significantly correlated with the modeled ratio of bedrock and surface waters, although the Sr-87Sr-86 ratio of hair was most strongly correlated with the measured ratio of tap water. The Sr-87Sr-86 ratio of hair is related to the ratio of tap water, which varied geographically. The ratio of hair provided geographic information about an individual's recent residence. Differences in the Sr-87Sr-86 ratios of hair and hair leachate may be concomitant with travel and could potentially be used as a screening tool to identify recent movements.
Date Created: July 20, 2021