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Angewandte Chemie International Edition ,
May 4, 2010
Death by Arsenic
Hair analysis proves it: Legendary racehorse Phar Lap died of arsenic poisoning in 1932
Contact: Ivan M. Kempson, Academia Sinica, Taipei (Taiwan)
Registered journalists may download the original article here:
Synchrotron Radiation Reveals Arsenic Poisoning and Metabolism in Hair: The Case of Phar Lap
Lap was a legendary racehorse that won many notable races.
After its triumph in the famous Agua Caliente Handicap in 1932 in
Mexico, the animal died in agony under mysterious circumstances while on
tour in the USA. One of the suggestions at the time was that Phar Lap
had been poisoned. Ivan M. Kempson (Academia Sinica, Taiwan) and Dermot
A. Henry (Museum Victoria, Australia) have now subjected the horse’s
hairs to a very thorough examination. As the researchers report in the
the animal does indeed seem to have died of arsenic poisoning.
of many substances that enter the body eventually also wind up in the
hair, where they accumulate. Hair analysis has often been used to detect
drug use or to posthumously uncover poisoning as the cause of death.
After his death, Phar Lap was prepared and stuffed and displayed in
Museum Victoria in Melbourne. “We were able to obtain small pieces of
the hide and mane with the roots intact,” reports Kempson. They only
examined hairs that were unquestionably still growing at the time of
death. These were individually analyzed along their entire length with
synchrotron X-ray fluorescence spectroscopy at the Advanced Photon
Source in Chicago. This method
detects even trace amounts of chemical elements because each element
emits very characteristic radiation.
scientists looked at the arsenic content of the hairs. “They found a
small amount of arsenic that was relatively evenly distributed over all
of the hairs. This is in agreement with the arsenic content of the
chemicals used to preserve the hide,” says Kempson. “In addition, we
found a considerably elevated arsenic content at the same distance from
the root in each of the hairs we examined.”At the time of the horse’s
death, this part of the hair was under the surface of the skin.
you take into account the rate of growth for horse hair and the
metabolic rate, the location at which the elevated arsenic concentration
was found indicates that the horse must have eaten and metabolized the
arsenic,” explains Kempson. In addition, the scientists used an X-ray
technique that can distinguish the chemical environment of the arsenic.
Says Kempson: “ The arsenic species identified also suggest that Phar
Lap died of arsenic poisoning.”
it is impossible to know how the horse ingested the arsenic. Was it
deliberate poisoning by competitors or enviers? Was it an accident—perhaps an overdose of the arsenic-containing tonics popular at the
time? Was the feed contaminated? “That will always remain a mystery,”