— Radioactive traces have now been found on two British Airways passenger planes currently grounded at Londons Heathrow Airport, the UK Home Office announced on Wednesday. Three other planes, also suspected of contamination, are now being examined, on Thursday.
The web of intrigue surrounding the apparent assassination of former Soviet spy Alexander Litvinenko, on 23 November, appears larger and more complex than ever on Thursday, as the inquest into his death opens in London.
UK authorities are currently tracing many thousands of people who may unwittingly be at risk, after coming into contact with the radioactive material suspected of poisoning Litvinenko. This now includes the 33,000 passengers and 3000 aircrew that flew on any of the 221 flights that the five planes made between 25 October and 29 November. The risk to these people, however, is thought to be very low.
Adding to the international drama, former Russian prime minister Yegor Gaidar is currently in a Moscow hospital recovering from a suspected poisoning thought to be connected to the death of Litvinenko, Russian newspapers reported on Thursday.
Gaidar's daughter Maria said he was in a "satisfactory" condition late on Wednesday but "there was a serious threat to his life" after he fell ill on 24 November in Ireland, where he had been attending a conference. The doctors will make their final diagnosis on Friday, but "a poison unknown to civilian medicine" is deemed the most likely cause of his illness, a hospital spokesman said.
Meanwhile, possibly the most delicate autopsy ever performed in London is due to take place on Friday, when radiation-suited pathologists gingerly prise apart the highly toxic body of Litvinenko. What they find might suggests where the radioactive element polonium-210 suspected of poisoning him came from.
Litvinenko, aged 43, claimed to have been poisoned at a London sushi bar on 1 November, and died 23 days later, following symptoms of radiation sickness. Polonium-210 was found in his blood, and at several London locations including his home and the sushi bar (see Radioactive element found in blood of Russian ex-spy).
It looks like a typical 30-day radiation death, says Dudley Goodhead, former director of the British Medical Research Councils Radiation and Genome Stability Unit at Harwell in Oxfordshire.
A person dies of the highest doses of radiation immediately. If the dose was high enough to destroy the intestinal wall, death takes five days, Goodhead explains. At lower doses, enough to destroy the bone marrow, a particular syndrome sets in with death typically at around 30 days, with some variation. Both Litvinenkos symptoms and time to death are consistent with that, he says.
That means he probably received only microgram amounts of polonium, Goodhead suggests. But only half would have been cleared from his body before he died. There will be plenty left for the autopsy team to worry about, as the polonium would be distributed widely throughout the body.
Since the radioactive element decays fast, with a half-life of only 138 days, the alpha particles it emits possess very high energy, making even tiny amounts toxic. As an unexplained death, by law Litvinenko must receive an autopsy. But just the small droplets released, for example, as the autopsy team opens his chest, could be dangerous.
New Scientist understands, from sources close to the case, that the examiners will be wearing the space suits used to fully protect scientists from toxic exposure.
But those high-energy alpha particles also make polonium easy to identify. The team should take samples from the liver, spleen, kidney, lung and other tissues, reduce them to ash, and test them with an alpha spectrometer, says Goodhead. That should reveal what dose of polonium Litvinenko received, and whether it was in particles or soluble.
Combined with tests for beta and gamma emissions, the samples will also reveal what other radioactive elements are present, if any, and that could point to the poloniums source. If it was diverted from the eight grams Russia sells to the US each year, for use in anti-static devices, the mix of elements should match (see Ex-spy's polonium poisoning suggests sophistication).
If it was produced by bombarding bismuth with neutrons in a research reactor, some of the bismuth, and its daughter product, thallium, could remain. And if it was isolated from the rogues gallery of radiochemicals in nuclear reactor waste it could be accompanied by ruthenium, and even plutonium.
Passengers concerned that they may be at risk from the radioactive material are advised to call the BA helpline, on 0845 6040171 from the UK, or on 0044 191 211 3690 for international calls.
More Science News from New Scientist
Ex-spy's polonium poisoning suggests sophistication
Radioactive element found in blood of Russian ex-spy
Cold war, hot secret