POISONS ‘The Sheffield Scientist’ Forensics Corner with Dr. Miranda Trojanowska

by Dr. Miranda Trojanowska

Forensic toxicology deals with the investigation of toxic substances, environmental chemicals or poisonous products. The most common samples examined by forensic toxicologists are blood, urine, and hair, as these can be easily collected and provide a great deal of information regarding both the historical and present influence of various substances. Post-mortem sample collection also includes an examination of the contents of the gastrointestinal tract, which is likely to contain evidence of consumed drugs or toxins that are yet to be digested. The liver, spleen, fluid of the eye, and brain may also hold valuable information regarding the cause of death.

The founder of the science of toxicology was Mathieu Orfila (1787 –1853), a Spanish toxicologist and chemist. In Orfila’s time, the primary type of poison in use was arsenic, but there were no reliable ways of testing for its presence. Orfila created new techniques and refined existing techniques to develop a reliable method. In 1840, Marie Lafarge was tried for the murder of her husband using arsenic. Her case became notable because it was one of the first trials to be followed by the public through daily newspaper reports. Orfila was able to prove that indeed she had poisoned her husband using arsenic and she was found guilty. Lafarge was the first person convicted largely on direct forensic toxicological evidence. Ricin is one of the most dangerous poisons in the world, found in the seeds of the castor oil plant. Once in the body, ricin attacks the central nervous system and vital organs, and death by multiple organ failure

Mathieu Orfila (1787 –1853)

or cardiovascular shock will occur within a few days. Ricin became famous in the Georgi Markov murder case. Georgi Markov was a Bulgarian dissident writer in London in 1978. A communist agent fired a tiny bullet laced with ricin, from a specially adapted umbrella, into Markov’s leg and he died three days later. It was alleged that the ruling party in Bulgaria ordered the assassination of the writer because Markov criticised the communist regime in power at the time.

In 2006, Polonium 210, a radioactive element found in uranium ore, was used to poison a former Russian agent, Alexander Litvinenko in London. He drank tea laced with the Polonium 210 and died from radiation poisoning three weeks later. It was thought he was silenced after speaking critically about what he saw as corruption within the Russian government. Fugu is a pufferfish traditionally used in Japanese cuisine that can be lethally poisonous. The poison is 1,000 times more deadly than cyanide, with no antidote. Only highly qualified chefs are allowed to prepare the dish as the toxic parts (the liver, mostly) need to be removed to avoid contaminating the fish to be used in the dish. The poison affects the nervous system, paralyzing victims and preventing them from breathing and they eventually die if the toxic parts are not removed properly. Fugu is well-known for being a dish that stands a good chance of killing the person it’s served to, but people still eat it, maybe because they like living life on the edge when there is just enough of the toxin left to cause your mouth to go numb after eating it.