Polonium-210 as a Poison
21 March 2007
The Health Protection Agency's radiation protection experts, together with colleagues from research laboratories in the USA, have published a paper in the Journal of Radiological Protection 1 on how polonium-210 acts as a poison in the body.
Although the unfortunate death of Mr. Litvinenko in London last year stimulated this work, the paper does not examine the particular circumstances of his death. Instead the authors review published scientific evidence accumulated over decades about the biological behaviour of polonium-210 and its deleterious effects at high doses, and estimate how much would have to be consumed to give a lethal dose.
The authors conclude that polonium-210 ingestion of 1GBq to 3GBq or more is likely to lead to death within a few weeks, assuming 10% absorption to blood (0.1GBq to 0.3GBq). On reaching the bloodstream, it would be rapidly deposited in major organs and tissues including the liver, kidneys and bone marrow. The intense alpha radiation within these tissues would result in massive destruction of living cells, leading to a rapid decline in health.
Anyone receiving such doses would show symptoms of acute radiation sickness syndrome, and death would eventually result from multiple organ failure. Remedial medical treatment strategies are unlikely to be successful once significant amounts of polonium-210 have entered the blood stream and deposited in tissues, within a few hours of ingestion.
This conclusion arises primarily from an expert assessment of available experimental data, supported by human data on the biological behaviour of polonium-210 and on effects of external radiation. There is only limited information on effects of polonium-210 in humans: the data from the Litvinenko case is not currently available because it is part of a criminal investigation.
Dr. Roger Cox, director of the agency's centre for radiation, chemical and environmental hazards said, "The tragic death of Mr. Litvinenko in London brought the attention of the world to polonium-210. Although it is widespread in the environment in minute quantities and is familiar to most radiation scientists, the use of polonium-210 as a poison is unprecedented in our experience. This paper is an expert review of the available scientific data on polonium-210 and estimates what is a lethal quantity."
