Page 38 - Veritas

FORENSIC SCIENCE GLOBAL NEWS UPDATES

STABLE ISOTOPES OF WATER HELP

IN LOCATION IDENTIFICATION

Isotopes are atoms of the same element hav-
Ms. Nivya George ing a different number of neutrons and differ

in atomic mass with the same chemical prop-
erties. Isotopes are present everywhere in the world in a different ratio,

12
2
18
making them forensically significant. H/H, O/ O, C/ C are the com-
16
13
mon stable isotopes. Hydrogen: protium, deuterium, tritium, and Oxygen:
16
17
18 O, O, O are the stable isotopes of water. The ratio of stable isotopes of
water differs from the coastal region to inland.

The heavier isotopes are seen in the coastal area while they become lighter
and lighter, moving towards the inland. The reason for this difference is

when it rains, the higher molecules like D O ( O and deuterium) fall first
18
2
near the coastal region, and when it moves inland, the D O molecule gets
2
lower, and the H O molecule starts to fall more.
2

The analysis of water-stable isotopes in the body helps to find the location

of each species. The body likes to build up with the help of water mole-
cules of different isotopes i.e., hydrogen and oxygen. The species near the

sea contain heavier isotopes while species in the forest have lighter ones.
The ratio between heavier and lighter molecules of water isotopes helps to

find the movement of a species from different geolocation on earth. For
example, if a species lives in hills for more than 10 years and comes to a

coastal region and lives for 5 months, the examination of the ratio of water

isotopes shows lighter molecules of oxygen O than heavier oxygen O in
16
18
the body. The analysis of water isotopes can also provide more information
about the location, habit, living conditions, etc.

The hair and nail of a species are more likely to be taken for the analysis
of water isotopes. Hair and nail leave an isotope timeline that remains

unchanged. Oxygen isotopes are incorporated into all other parts of the
body than hair and nail. If a person continues to travel from place to place

VERITAS 23