Al Jazeera reports:
Swiss scientists who conducted tests on samples taken from Yasser Arafat’s body have found at least 18 times the normal levels of radioactive polonium in his remains. The scientists said that they were confident up to an 83 percent level that the late Palestinian leader was poisoned with it, which they said “moderately supports” polonium as the cause of his death.
A 108-page report (PDF) by the University Centre of Legal Medicine in Lausanne, which was obtained exclusively by Al Jazeera, found unnaturally high levels of polonium in Arafat’s ribs and pelvis, and in soil stained with his decaying organs.
The Swiss scientists, along with French and Russian teams, obtained the samples last November after his body was exhumed from a mausoleum in Ramallah in the occupied West Bank.
Dave Barclay, a renowned U.K. forensic scientist and retired detective, told Al Jazeera that with these results he was wholly convinced that Arafat was murdered.
“Yasser Arafat died of polonium poisoning,” he said. “We found the smoking gun that caused his death. What we don’t know is who’s holding the gun at the time.”
“The level of polonium in Yasser Arafat’s rib…is about 900 milibecquerels,” Barclay said. “That is either 18 or 36 times the average, depending on the literature.”
UPDATE: I just glanced at the Swiss report. It is not the slam dunk that Al Jazeera pretends, although the conclusion is that "the results moderately support the proposition that the death was the consequence of poisoning with polonium-210."
Arguments against it include the fact that polonium was itself not found on Arafat's remains, but lead-210 was, which is assumed to be masking the polonium. (I don't understand this because other charts show Po210 on the remains.) The existence of the lead-210 could not be adequately explained by other factors (like smoking or the high levels of radon in the grave.) The report also points out that the lead concentrations were not uniform on his body, and they assume that if it had a different source it would be.
The report is relying on both the toxicology reports and the previous report of polonium on his underwear and other personal effects. If those were tainted, the conclusions might be different.
There is very little forensics literature about the effects of ingesting polonium so anything that the report says about the month delay between Arafat's meal that got him sick and his death is pure guesswork.
While there are valid issues brought up in the report, it is not definitive.
UPDATE 2: Also relevant:
Framework of our investigations
In examining the toxicological and radio-toxicological investigations, four particular critical problems must be pointed out:
• There was a lack of adequate biological specimens, thus limiting the possibility to perform further analyses. This was partly due to the fact that the blood, urine, fecal and cerebrospinal fluid samples taken during the patient's hospitalization at Percy were subsequently destroyed. In addition, there were no samples taken at an early stage when the initial symptoms developed.
• As a result, our initial investigations were performed on very small specimens, such as a single hair shaft, or on atypical specimens, such as the sweat in the patient's clothing or traces of blood and urine found on his personal effects in the travel bag. The same investigations were performed on biological specimens (hair, bone, scalp) and on non-biological specimens (soil, shroud fragments) collected after exhumation of the deceased in Ramallah. In any event, all of these specimens proved problematic in terms of their analysis, as well as for the interpretation of the results. We have limited experience working with such specimens and very little has been published in the scientific literature.
• In addition, the fact that eight years passed between the death of the patient and the implementation of toxicological and radio-toxicological investigations contributes to the uncertainty of the analytical results and their interpretation. After such a long delay, especially under less than optimal conservation conditions (ambient temperature of the travel bag, burial), one cannot exclude the possibility of chemical degradation or redistribution with the surrounding environment. When considering radio-toxicological elements, one must keep in mind that they have a very short half-life (138 days for 210Po), rendering their detection eight years after a possible administration very difficult and subject to large uncertainties. Furthermore, the elapsed 8 years prevented us from directly measuring the soft tissues (i.e. liver or kidneys) that would have been more suited to confirm the presence or absence of artificial polonium, as was found in the clothing of President Arafat.
• Finally, the "chain of custody" of the specimens contained in the bag cannot be documented between the death in November 2004 and their reception in Lausanne in February 2012. This was not the case for the specimens collected during the exhumation.
UPDATE 3: Under the "Security Measures" section, the report says "The access to the grave was highly restricted and controlled by the Palestinian Authority." Not exactly a "chain of custody."