A poisonous potted history

What killer compounds have emerged from the history books?
09 January 2018

Interview with 

Dr John Emsley, chemist and author




How have poisons been used throughout history? Katie Haylor caught up with chemist and science writer John Emsley, author of Molecules of Murder and More Molecules of Murder, to find out...

Katie - As the old saying goes - “an apple a day keeps the doctor away.” But, eat enough apples in their entirety and you could, in theory, risk cyanide poisoning from all those pips. But now we know the ingredients of a good poison: low fatal quantities, being hard to detect, do we have any good, or should I say bad candidates?

The history books may be a good place to start looking. Chemist and author John Emsley knows his primitive poisons. He explains how the Victorians poison of choice was one readily available in the pharmacy, which meant some rules had to be put in place…

John - To purchase poisons from a pharmacist, you had to sign the poisons register and the pharmacists had to recognise who you were. You couldn’t just walk into any shop and buy it. That was done because there were too many murders mainly with something like arsenic, as it’s oxide was known as white arsenic and this was widely used as vermin poison and things like this. Colouring agents could be made from it so it was available. Because it was available it was being used to dispose of unwanted relatives and things like that.

Katie - Okay. Are there any particularly famous cases of this?

John - There’s some very famous cases in history. But going back even earlier to the 17th century the Marquise de Brinvilliers in France murdered her relatives to secure the family income. She was only detected because the man who was supplying it, her lover, suddenly died and they discovered her letters. The thing about that was this was one of the first cases in which someone was asked to prove that the powder they detected was the deadly poison. That was in 1676, and a pharmacist in Paris devised a set of test to prove that what they’d found was actually arsenic and it worked, and she was found guilty and executed.

Katie - What is it fundamentally about arsenic that makes it such an effective poison?

John - The think is it’s in the same group of the periodic table as phosphorus. Phosphates, of course, are essential in lots of parts of the human body from DNA upwards and, of course, if you put arsenic there the body can recognise arsenic and thinks it’s getting phosphates. It will introduce arsenic at all sorts of points and then, of course, these things won’t behave as they should behave and very quickly you’re made very ill. The body recognises arsenic as something it doesn’t want very quickly but not before it’s absorbed quite a lot of it. Then, of course, it screws up various parts of your body and, with a big enough dose, you die within a day or so.

It will attach itself to something called ATP (Adenosine Triphosphate) and, if does that, then it really interferes because ATP is needed in every cell of the body. Then things begin to break down because you need ATP to generate energy in your heart, for example. If you can’t generate enough energy then you’re going to be in real trouble.

Katie - The chemical element arsenic’s availability and toxicity made it the perfect poison of the day, but it could be detected. So could a poisoner try to mask their ill intentions by using a substance that is already found naturally in the body?

John - Adrenaline is one that has been used in murders. The chemical name for it is epinephrine, and this the body produces and it produces a lot of this if you’re under sudden stress.

Katie - This the ‘fight and flight’ response, isn’t it?

John - Yes. If you’re having a heart attack they may give you this to stimulate the heart and keep it going. It’s not something you would normally think of as being a poison but it has been used by nurses. Nurses, of course, have access to it and those are the ones who generally murder with adrenaline because they know if you give too much adrenaline it’s going to over-stimulate the heart and the heart will pack up.

The serial killer nurse called Kristen Gilbert probably killed about 50 of her patients with adrenaline. She worked at the Veterans Hospital in Northampton, Massachusetts and she did it for a variety of reasons. If the person began to annoy her, then she would give them an overdose. Often these people were very ill and so it was just put down to the person had died of natural causes. But, eventually, she got rather careless in that if it was someone in intensive care, and she wanted to go out with her boyfriend and the person in intensive care couldn’t be left, she would give them an overdose of adrenaline and pass them onto the next world. It’s not known exactly how many people she dealt with, but it was probably around 50 before she was finally caught.

The thing about that was it became so common this occurrence of people she was supposed to be looking after suddenly dying that they began to investigate. Other nurses said there’s something odd about this - I think they called her The Angel of Death, or something like that. They began then to analyse the body and, of course, were able to detect there was far more adrenaline in the body of the dead person than the body itself could actually have produced. They were able to go back and analyse samples from bodies that had been dead two or three years and there was still excess adrenaline.

Katie - Despite being a chemical that pre-exists in the body even adrenaline can’t stay hidden for long when given in lethal doses. So how about something so deadly, something which is needed in such a small quantity to cause harm, but it’s virtually undetectable?

John - The thing about polonium chloride is that it’s radioactive but it gives off only alpha particles. Alpha particles are relatively harmless; a sheet of paper will stop an alpha particle. It doesn’t give off gamma rays. Gamma rays are the things that you can use a geiger counter to detect. With polonium it was possible, the Russian Secret Police found, to pass through the parts of airports where you go through a thing and it will detect if there’s anything radioactive on you. They could pass through that so they were using this to dispose of people. The amount of polonium you need to kill someone is so tiny it’s difficult to see - it’s as small as a mote of dust. It is that deadly.

Katie - Polonium is radioactive. Once inside the body the alpha particles emitted by polonium can make their way into cells, damage DNA, and cause cell death.

John - We know our cells have got  a wonderful repair mechanism that’s being used all the time because cells are needing repair. Of course, it can be repaired but not when you’re giving off something like a 100 million of these particles a second, then there’s not way the body is going to be able to cope with that.

The most famous poisoning of this was someone called Alexander Litvinenko and he came to Britain. He was a KGB agent and after the end of the Soviet Union a lot of people from Russia could then come and live in Britain. He came to Britain and he was granted asylum because he said he was ex KGB and he was able to tell the British secret people a lot about it, so we took him in and he was given another name. He was called Edwin Redwalt Carter, and he was given a house with him and his family in Muswell Hill in London and he began to lead quite an anonymous life.
The trouble was, when he was visited by his wife’s mother, she went back to Russia and the police there knew who she was. They searched her luggage and they found out details of  who he was and where he lived, so they then sent another agent to London to dispose of him and that agent came with polonium chloride. He was an old “friend” of Litvinenko and he invited Litvinenko to the Millenium hotel where he was staying London, and there he had green tea with polonium chloride in it.

Of course, the following day he began to feel ill. The doctor diagnosed gastroenteritis, the usual reaction to something you’d eaten. Put him in hospital; he got no better; sent down to University College Hospital because he obviously was seriously ill. His hair began to fall out, which is sometime a sign of thallium poisoning, and thallium’s a deadly metal. But they detested for thallium and no it wasn’t thallium and so they knew his hair was falling out because of radiation damage. The chemists, the scientists, detected polonium and, suddenly, it was obvious what was killing Alexander Litvinenko, and he died after about three weeks in hospital.

Katie - Death by radiation. No taste, no smell, and given in miniscule quantities. It’s polonium’s volatility that led to its detection. Once identified, scientists were able to detect the traces it left behind on various surfaces, even including the seat in Arsenal Football Stadium where the killer had sat to watch a match.

John - We are only talking now of a few atoms and yet, there it is and there it can be detected. Even that supposedly undetectable poison that the Russians were using is now no longer in that category of undetectable.

Music: Daniel Birch & Ben Pegley


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