Can science solve mystery surrounding Arafat's death?

http://www.bbc.co.uk/news/world-middle-east-20512753

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By Nina Lamparski BBC News

Almost a decade after Yasser Arafat's death, three teams of scientists are carrying out tests on his remains to determine whether he may have been poisoned by polonium-210.

It is the same rare and highly radioactive element which killed Russian ex-spy Alexander Litvinenko in 2006.

While Arafat's tomb was resealed shortly after the exhumation, test results are expected to take at least several months.

The investigation raises important questions about how much evidence experts can expect to find at this stage, and whether they will be able to draw definite conclusions.

In March, first findings of polonium-210 in samples taken from Arafat's urine, blood and clothes were deemed inconclusive. The evidence could have been contaminated after his fatal stroke, experts say.

But even if the new probe confirms the presence of polonium-210, scientists will face another hurdle - determining whether the levels were elevated enough to have killed the Palestinian leader.

For Bertrand Ludes, the director of Strasbourg's Forensic Medicine Institute, the time lapse is less relevant with regards to the scientific outcome.

"If there has been polonium poisoning, it will have deeply penetrated into the body's tissues and still be detectable today," he told the BBC.

The real issues surrounding Arafat's death will arise once scientists have completed their work, according to Mr Ludes.

"Given that polonium is neither naturally present in the body nor in the land, one can assume Mr Arafat would have been exposed to it in other ways," he said.

"That's why it's important to distinguish between what science can or cannot answer. Science can assess the quality and quantity of polonium but it is unable to shed light on how it got there in the first place. That is a matter for criminal investigation."

Lack of context

However, forensic pathologist Dr Stuart Hamilton says eight years is a very a long time to wait to undertake an examination.

Getting answers could prove "very troublesome", according to the British expert who has experience in exhuming graves.

"The longer the interval between someone's death and the examination, the more difficult it is to get the info you need, and the more difficult it's going to be to interpret it," Dr Hamilton told the BBC's Newsday programme.

Interpreting information is an essential part of forensic pathology as physical evidence is often not enough to obtain answers, he added.

Scientists need context to gain proper insight into how someone has died. The more time has passed, the harder it is to understand the circumstances surrounding the death.

"In the simplest sense, if they do identify polonium or radioactive material, it doesn't necessarily answer why he's dead if you don't have the alternative hypothesis that was put forward initially," Dr Hamilton said.

"The initial [thought] was that he had a stroke. The brain is very likely to have decomposed by this point so it's going to be very difficult to even see if that may have been the case."

If polonium-210 is indeed found in Arafat's body, it will nevertheless be difficult to calculate the exact amount present at the time of his death.

The radioactive element has a so-called half-life of 138 days, which means levels decay by half every 138 days. Around 21 half-lives had already passed when scientists first discovered traces of the material in March.

"Trying to interpret back what levels of radiation there would have been eight years ago and whether [they were] sufficient to be fatal, is going to be very, very difficult," Dr Hamilton said.

"It's going to take a lot of these scientists a lot of time and a lot expertise to tease out the facts and then interpret them in the context of the body."

Given the uncertainties involved in the forensic analysis, the test results are also likely to be contestable in court, he added.

"If you can't say other things haven't happened - for example the stroke that was initially put forward as the cause of Mr Arafat's death - if you can't refute that scientifically, it's going to be difficult to prove that beyond reasonable doubt in a court of law."