# Considerations for Stable Isotope Analysis of Human Hair The Impact of Postmortem Environmental Exposure

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Published: Oct 26, 2021
DOI: https://doi.org/10.5744/fa.2020.0052
Keywords:
forensic anthropology, stable isotope analysis, postmortem hair analysis, taphonomy

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Tiffany B. Saul
Forensic Institute for Research and Education, Middle Tennessee State University, 1301 Main Street, Box 89, Murfreesboro, TN 37132, USA
Lesley A. Chesson
Defense POW/MIA Accounting Agency (DPAA) Laboratory, 590 Moffet Street, Building 4077, Joint Base Pearl Harbor-Hickam, HI 96853, USA
Dawnie W. Steadman
University of Tennessee, Department of Anthropology
Gwyneth W. Gordon
School of Earth & Space Exploration, Arizona State University

## Abstract

Stable isotope analysis of postmortem hair is performed in order to make inferences about an individual’s diet and geographic travel history prior to death. During analysis and interpretation, investigators assume that the hair collected from a postmortem environment has not been altered by exposure conditions and that the isotopic “signatures” of hair prior to exposure are preserved in postmortem samples. In order to confidently make inferences from postmortem hair samples, it is necessary to know whether their isotope ratios undergo postmortem changes. To address this question, post-exposure hair samples (n = 44) were collected from known body donors at the Anthropology Research Facility in Knoxville, Tennessee, USA, at various time points ranging from 22 to 1,140 days of exposure. These samples were analyzed for carbon (δ13C), nitrogen (δ15N), hydrogen (δ2H), and oxygen (δ18O) isotope ratios, and the results were compared with pre-exposure hair samples collected from the same donors. This study highlights considerations for the interpretation of isotope ratios obtained from postmortem hair samples in forensic contexts. The results indicate that δ13C, δ15N, and δ18O values from human hair remain relatively consistent over periods up to three years of outdoor exposure, while δ2H values changed significantly between pre-and post-exposure hair samples.

## Article Details

Issue
Vol. 4 No. 3 (2021)
Section
Research Articles