Evening star., 1954-05-24
Hair Reveals Secrets
Of Arsenic Poisoning
RADIOACTIVE Detectives
Developed in Europe
By Thomas z. Henry

A technique for detecting arsenic I'D
human hair In amounts az small I'd
300th Of billionth Of an ounce had
been developed BY French and British
atomic scientists as an aid 10 crime
detection.
knowing the rate Of human hair
growth, 1t also Is possible by this
method TO determine. In many cases,
the date when the poison was taken Into
the system and the rate ct which the
doses were given,
The new technique promises to be
Of great Importance to police inves-
tigating suspected cases Of murder by
arsenic poisoning. It Is described by
DR.. A. A. Smales, head Of the ana
lytical chemistry department Of the
British Atomic Energy Research Center.
The technique is that Of radioac-
tivation. A sample Of the hair, or other
material that Is to be analyzed II bonn
barded with slow neutrons from an
atomic pile. such as Is available ct
the British Harwell establishment or
at several plants of the Atomic Energy
Commission. This creates radioactive
isotopes Of various elements contained
in the sample. The identity of these
elements can be determined from their
rate Of disintegration, or half lives,
by means of Geiger counters.
Compared with Known.
The number Of isotopes formed In
pure sample Of arsenic Of precisely de-
termined mass Is known. This Is com.
pared with the number found In the
hair sample. Thus very precise de-
termination Of the total amount Of the
element present can be found. Hair,
1t is known, takes up arsenic In the
body very quickly. but In hitherto
hardly determinable amounts. BY the
present technique it is theoretically
possible to determine that q person
was given a certain dose of arsenic one
day. none for the next two days, and
then a certain dose on the fourth day.,
It should be possible to pin-point the
date on which a fatal dose was given.
Thus possibly some suspect might be
eliminated by proving complete alibi.
The method was worked out. Dr.
SmaleS says in the London Times
spring science reviews, by two French
chemists. DrS. II. Griffon and j. Bar.
baud who irradiated the hair in the
French atomic pile Zoe at Paris. At
first the results were somewhat confuS.
ing because Of the radioactive iSotopes
OF sodium and sulfur, with quite similar
half lives. which also were created by
the irradiation. They now have de-
veloped the technique, however, to the
point where they can detect the arsenic
clearly and find any increases over the
normal level. There is some arsenic
in everybody's hair all the time.
Aside from its chronological aspects
the technique has become of consider
able industrial Importance in deter
mining the amount of arsenic contain
ination of the rare element germaniura
which is the central factor in the mi-
mute "transistors" which now rapidly
are replacing vacuum tubes in much
electronic equipment.
Properties Vary.
Arsenic is one Of the elements OF
which the most precise determinations
can be made.
They can determine amounts of the
rare earth'S europium and disprosium iI
amounts as small as quadrillionth Of
a gram. In the same class with arsenic
are antimony, bromine, copper, galliun1
gold. iodine, palladium. scandium,
tantalum, turbium. thulium, and tungt
stem. Many other elements. however,
can be detected only when there are
concentrations at least 10 times ab
great.
The hair. nail clippings. or whatever
else is used remains intact after thib
procedure for whatever further usb
police wish to make Of 1t.
The same methods now, are beinS
used at the University Of Chicago t4
detect the barest traces Of elements in
meteorites and these studies are throwt
ing new light on the structure and
history of the solar system.
The method, DR.. Smales reports
dates back to 1886. shortly after the
discovery Of artificial radioactivity
when it was used by the Danish physit
cist G. Hevesy to detect minute
amounts Of the rare earth elements
It was Of little practical Importance.
however, until the present atomic pile4
came into existence.