Polonium-210 - Litvinenko Case

  • B
  • Thread starter Jimmy87
  • Start date
In summary, the conversation discusses various aspects of radioactivity, including how assassins may have used a small liquid vial to contaminate a victim's drink, why alpha particles are dangerous and how they can be detected using specialized equipment. The conversation also touches on the concept of contamination trails and the sensitivity of radiation detectors.
  • #1
Jimmy87
686
17
Hi,

I have been asked to write a case study on this in class as one of the modules we are doing is radioactivity. There is tons of stuff online but I had a few specific questions that I would be grateful if someone could answer:

1) How would the assassins have carried the poison and how did everywhere get contaminated? They found a huge contamination trail around London and I just wondered how everywhere became contaminated - I would have guessed it was just dissolved in a liquid that they just poured in his tea so I don't get how the assassins got it all over them and it was everywhere they went e.g. on their British Airways flight seat, hotel room etc.
2) Why is alpha so dangerous? I know alpha particles are the most ionising forms of nuclear radiation but if it is stopped by your skin then even if you ingest it, is it not just as easily stopped inside your body? Or is it because the tissues are more delicate inside your body?
3) I am trying to write some stuff on radiation sickness. Would the poison have damaged DNA and created free radicals or would it have just outright killed the cells in the body?
4) In this documentary we were asked to try and watch, it says that alpha radiation triggers no alarms. I was just wondering what piece of equipment they were using in the documentary as they said they got a full scale deflection on the tea pot that Litvinenko drank from for alpha particles. How does it differ from a Geiger counter (as they said these don't really detect alpha particles) and what makes it much more sensitive for detecting alpha particles?
5) A bit of a political question but why is no-one in the British government doing anything more about this case? We were asked to watch the most recent and up to date documentary on this (http://www.channel4.com/programmes/hunting-the-kgb-killers) which says that Scotland Yard found conclusive evidence and charged Andrea Lugovoy with murder. It says that they tried to extradite him to stand trial but they were denied by Russia. Why don't the British government do anything else? Someone has murdered a British citizen on British soil and they have been charged with murder by the Crown Courts. We ask for Lugovoy, Russia say no and that's it?

Thanks for any help answering any of these questions.
 
Physics news on Phys.org
  • #2
Let’s stay away from politics here. Physics questions are fine.

Radiation detectors are really sensitive and atoms are tiny - even minuscule traces of radioactive substances can be detected. Liquids evaporate partially, gases can leak, solids can be picked up partially by touch - everything contaminates everything all the time, typically this is not an issue. With radioactive materials it means detectors can notice something was in contact with a strong radioactive source.

Alpha particles are stopped quickly even inside the body - but this stopping process means damage to the cells. For most molecules this is not an issue, but for some of them (especially DNA) it is. If there is too much damage within a cell the cell dies. If too many cells die this kills the whole human.

Alpha particles are stopped by the entrance of most radiation detectors, but there are special detectors with very thin entrance windows that can detect alpha radiation. There are also some other options, e.g. measure the ionization from the particles like a smoke detector (but here the unknown component is the radioactive source, not the smoke).
 
  • #3
mfb said:
Let’s stay away from politics here. Physics questions are fine.

Radiation detectors are really sensitive and atoms are tiny - even minuscule traces of radioactive substances can be detected. Liquids evaporate partially, gases can leak, solids can be picked up partially by touch - everything contaminates everything all the time, typically this is not an issue. With radioactive materials it means detectors can notice something was in contact with a strong radioactive source.

Alpha particles are stopped quickly even inside the body - but this stopping process means damage to the cells. For most molecules this is not an issue, but for some of them (especially DNA) it is. If there is too much damage within a cell the cell dies. If too many cells die this kills the whole human.

Alpha particles are stopped by the entrance of most radiation detectors, but there are special detectors with very thin entrance windows that can detect alpha radiation. There are also some other options, e.g. measure the ionization from the particles like a smoke detector (but here the unknown component is the radioactive source, not the smoke).

Thanks for the info. I am still not getting the contamination trail the assassins left though. I found out that the investigators think they used a small liquid vial. Surely you simply unscrew the lid, tip some in the drink and screw it back on? How can a contamination trail be left in over 40 locations!

What would the device be called they used to detect the alpha particle since it is not a Geiger counter. I have print screened the device from the documentary:

upload_2017-12-17_22-24-32.png
 

Attachments

  • upload_2017-12-17_22-24-32.png
    upload_2017-12-17_22-24-32.png
    62.8 KB · Views: 558
  • #4
Touch a coin in your wallet. Some of its metal atoms now stick to your finger. The next things you touch will get some of these atoms. Let’s say that includes a door knob. The next people touching this door knob will receive some of the atoms of your coin as well, and the following things these people touch will also get some atoms and so on. How long you can track these chains is mainly a function of the sensitivity of the detection method. The first step you can do with your nose - after handling a lot of coins the fingers smell notably. Radiation detectors that can measure individual decays (and therefore individual atoms) are much more precise.

You can use a Geiger counter for alpha emitters if you make it with a very thin window or if you can take a sample and physically put it in.
 
  • #5
mfb said:
Touch a coin in your wallet. Some of its metal atoms now stick to your finger. The next things you touch will get some of these atoms. Let’s say that includes a door knob. The next people touching this door knob will receive some of the atoms of your coin as well, and the following things these people touch will also get some atoms and so on. How long you can track these chains is mainly a function of the sensitivity of the detection method. The first step you can do with your nose - after handling a lot of coins the fingers smell notably. Radiation detectors that can measure individual decays (and therefore individual atoms) are much more precise.

You can use a Geiger counter for alpha emitters if you make it with a very thin window or if you can take a sample and physically put it in.

Thanks. No I get all that but if its in a vial then how will it get on your fingers? In your analogy it's like saying the coin is inside the vial so how would you ever get atoms of the coin on your finger?
 
  • #6
Someone made the vial, filled in stuff, closed the vial. Someone opened the vial, extracted something from it, closed the vial. All these people kept touching things.
Someone touched the cup and drank the now radioactive tea, and then continued touching things.
 
  • #7
Sometimes it can be difficult for people to comprehend just how small an atom is. Consider that the average human body is made of about 100 trillion cells. And one single cell is made of about 100 trillion atoms.

Mass of po-210 is 210 g per mole. 1 gram ÷ 210 gram per mole * 6.022E23 atoms per mole so 1 gram of Po-210 is about 3,000,000,000,000,000,000,000 atoms which would likely be carried as a silvery powder in a vial to mix in his tea. To keep that many atoms contained it'd have to be hermetically sealed and cleaned prior to shipping. An assassin likely did not take those precautions. Russeling around in a suitcase or pocket some likely leaked out. From there it easily spread through contact with his hands to other surfaces.

Alpha radiation is a helium nucleus with a charge of +2. So it strips two electrons from other atoms. Because it's big (compared to beta or gamma radiation) and heavily charged it is easily stopped but causes a lot of chaos in the process. Human skin is covered in a layer of dead cells. Even if you shower frequently they're still there. These dead cells absorb the damage from alpha radiation which has no effect because they're already dead, leaving healthy tissue underneath untouched. Inside the body it's all healthy tissue which causes huge problems when damaged.

Radiation causes atoms to ionize effectively stripping them of electrons making them charged. This causes molecular bonds to break and molecules basically just fall apart. It is essentially free radical creation but on a much larger scale. The majority of molecules in the body can handle this abuse. Theres always more to take its place. But the limiting factor is dna. When dna is damaged it can be difficult to fix. There are enzymes designed to fix DNA damage but this is primarily for damage incurred during the replication process, so it can't keep up with an assault from radiation.

The irony about killing someone with po-210 is that po-210 is chemically similar to selenium. Therefore if ingested it is likely to fill the role of selenium in where it is used in the body. Selenium is primarily used in antioxidant enzymes which work to absorb free radicals to prevent cell damage. So now you're sticking in po-210 and instead of preventing damage the enzyme is working to cause damage.

When dna is damaged this is primarily an issue during replication. An analogy I like to use is imagine DNA as instructions to build a tv. When you're using the tv it doesn't really matter if a few pages get ripped out of those instructions because you're not using them. Then when it comes time to build another tv you check the instructions and realize you can't do it. In that instance the cell kills itself, unless the kill itself instructions are damaged then it just does whatever it wants, i.e. cancer.

DNA is primarily damaged in a process call hydrolysis. A free electron breaks apart a water molecule causing a positive charged hydrogen atom and/or a negative charged hydroxide molecule. Those then pull an OH or H off the DNA to make a new water molecule causing the DNA strand to break.

Alphas are very difficult to detect for three reasons. First, they have a very small range. Alpha particles will only travel about 2.5 cm in air. So a lethal amount of alpha could be on a table and you could stand a meter away without protection without a problem. Second, they have an even shorter range through solid materials. Most alphas are stopped by a sheet of paper. Detectors for alphas need to have a very thin Mylar screen only a few microns thick. Otherwise alphas would never get through to be detected. Third, alphas tend to have long half lives. Po210 is very short at 138 days but am241, used in smoke alarms, has a half life of 432 years, and U238 has a half life of 4.5 billion years. Long half lives mean atoms don't decay that frequently, so more difficult to detect.

Alphas are typically measured with a Geiger Mueller detector with an alpha probe which is the one in the image with a long wide screen.
 
  • Like
Likes Jimmy87 and DrClaude
  • #8
For a complete scientific analysis of the dose Mr. Litvinenko received see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226196/

Just to elaborate on @Bigjoemonger's post. The lethal amount of Polonium is said to be about 1 ugm. To give you a prospective a grain of salt weights about 60 ugms. Taken orally Po-210 is mostly excreted (90%) in the feces. That which is absorbed is excreted in the urine, saliva, and perspiration with a 40 day half -time. The activity of 1 ugm of Po-210 is 166 106 dps. One ugm has about 3x10^1515 atoms. with a excretion half time of 40 days that means at the beginning every second about 600 million radioactive atoms are being excreted resulting in a decay rate of 37 dps continually to build for days prior to death.

At the time of administration large quantities would be left on the cup (if used), spoon, napkin as well as the victims mouth and hands. The victim not knowing he was contaminated would have left a trail of contamination for day's possibly weeks if he did not succumb by then. When medical patients are administered radioisotopes (which are usually short lived like I-131 which is one of the most problematic) for therapy they are given instructions to wash hands often wash clothes separately sometimes instructed to discard underclothes holding them for decay before reuse or disposal, use separate eating utensils, flush toilets twice avoid contact with children among other precautions to minimize exposure or contamination of others.


Handling highly concentrated sources if precautions are not strictly observed can result in significant contamination of the exterior of the primary container and anything with which it comes in contact . So the perpetrator (perhaps dispensable) and maybe unbeknownst to him be highly contaminated although not to a immediately lethal level. He might of received it clandestinely (no warning labels) by commercial carrier and being exclusively an alpha emitter the radioactivity would not be detected without at least opening the shipping container.

Contamination of just a few disintegrations per second are relatively easily detected . The contamination is typically difficult to remove even if you try often needing special processes. Most often, known contaminated articles are discarded and held in a secure place for decay to safe levels.
 
  • Like
Likes Jimmy87
  • #9
Because damaged dna is primarily an issue during replication, quickly dividing cells are most vulnerable. The cells that line your digestive system are exposed to a harsh chemical environment and divide and are replaced very rapidly. Thus the symptoms of Radiation Sickness caused by the damage to these cells. Nausea, diarrhea, and death. Blood marrow, sperm cells, and fetuses are also especially vulnerable. Brain cells are pretty radiation resistant as they are slow dividing. Young people are more vulnerable, and us old guys get more Rad-Hard each year. Send us old fellows into work at Fukashima.
 
  • Like
Likes Jimmy87
  • #10
mfb said:
Someone made the vial, filled in stuff, closed the vial. Someone opened the vial, extracted something from it, closed the vial. All these people kept touching things.
Someone touched the cup and drank the now radioactive tea, and then continued touching things.

I was just reading over this thread again and was wondering if someone could answer a question. The tea pot with polonium 210 was washed daily for 2 weeks before forensics analysed it. How can it give a full scale reading after being washed so many times? Also, if a minuscule amount is needed to kill someone then why didn’t multiple people die who drank from that pot within those first two weeks?

Thanks
 

1. What is Polonium-210 and how is it related to the Litvinenko case?

Polonium-210 is a radioactive isotope of the element polonium, with a half-life of 138 days. It was used to poison Russian ex-spy Alexander Litvinenko in 2006, leading to his death.

2. How was Polonium-210 used to poison Alexander Litvinenko?

It is believed that Litvinenko ingested the Polonium-210 through a cup of tea that was laced with the radioactive substance. The Polonium-210 was likely dissolved in the tea, making it easier to ingest.

3. What are the symptoms of Polonium-210 poisoning?

The symptoms of Polonium-210 poisoning include nausea, vomiting, diarrhea, hair loss, and damage to the central nervous system. In severe cases, it can lead to death.

4. How is Polonium-210 detected in the body?

Polonium-210 can be detected through a urine test, which can show elevated levels of the substance in the body. It can also be detected through a tissue sample or a post-mortem examination.

5. Who was responsible for the poisoning of Alexander Litvinenko with Polonium-210?

The British government has accused Russian agents of being responsible for the poisoning of Litvinenko with Polonium-210. However, Russia has denied any involvement in the case. The full truth behind the poisoning remains unknown.

Similar threads

  • High Energy, Nuclear, Particle Physics
Replies
6
Views
1K
  • Nuclear Engineering
Replies
4
Views
1K
  • Differential Geometry
Replies
29
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
18
Views
4K
Replies
16
Views
1K
Replies
3
Views
818
  • Other Physics Topics
Replies
5
Views
2K
  • Nuclear Engineering
Replies
22
Views
2K
  • Art, Music, History, and Linguistics
Replies
1
Views
1K
  • Quantum Interpretations and Foundations
2
Replies
48
Views
6K
Back
Top