Editing Isotope analysis (section)

=== Forensic science ===

A recent development in [[forensic science]] is the isotopic analysis of hair strands. Hair has a recognisable growth rate of 9-11mm<ref>{{cite book |first1=S. |last1=Black |title=Crime Scene Analysis |publisher=Reading University |year=2008 }}{{page needed|date=February 2018}}</ref> per month or 15&nbsp;cm per year.<ref>{{cite book |first1=P. |last1=White |title=Crime Scene to Court: The Essentials of Forensic Science |edition=2nd |publisher=Royal Society of Chemistry |year=2004 }}{{page needed|date=February 2018}}</ref> [[Human hair growth]] is primarily a function of diet, especially drinking water intake.{{citation needed|date=February 2018}} The stable isotopic ratios of drinking water are a function of location, and the geology that the water percolates through. <sup>87</sup>Sr, <sup>88</sup>Sr and oxygen isotope variations are different all over the world. These differences in isotopic ratio are then biologically 'set' in our hair as it grows and it has therefore become possible to identify recent geographic histories by the analysis of hair strands. For example, it could be possible to identify whether a terrorist suspect had recently been to a particular location from hair analysis. This hair analysis is a non-invasive method which is becoming very popular in cases that DNA or other traditional means are bringing no answers.{{citation needed|date=February 2018}}

Isotope analysis can be used by forensic investigators to determine whether two or more samples of explosives are of a common origin. Most [[explosive material|high explosives]] contain carbon, hydrogen, nitrogen and oxygen atoms and thus comparing their relative abundances of isotopes can reveal the existence of a common origin. Researchers have also shown that analysis of the <sup>12</sup>C/<sup>13</sup>C ratios can locate the country of origin for a given explosive.{{citation needed|date=February 2018}}

Stable isotopic analysis has also been used in the identification of drug trafficking routes. Isotopic abundances are different in morphine grown from poppies in south-east Asia versus poppies grown in south-west Asia. The same is applied to cocaine that is derived from Bolivia and that from Colombia.<ref>{{cite thesis |first1=J.R. |last1=Ehleringer |first2=J. |last2=Casale |first3=D.A. |last3=Cooper |first4=M.J. |last4=Lott |title=Sourcing Drugs With Stable Isotopes |url=https://collections.lib.utah.edu/details?id=703018 |year=2001 |publisher=Office of National Drug Control Policy }}</ref>