Polonium-210
The radioactive element from the Litvinenko murder. Also in tobacco.
At a glance
- Also known as
- Po-210 · ²¹⁰Po
- CAS number
- 13981-52-7
- Toxicity
Very high
- Carcinogenic
- Yes — IARC Group 1
- In cigarette smoke
- 0.04-0.30 pCi per cigarette (1.5-11 mBq, NIH/EPA)
What is Polonium-210?
Polonium-210 is a radioactively decaying isotope of the element polonium. It decays by emitting alpha radiation — high-energy helium nuclei that severely damage tissue in a confined area. Po-210 enters the tobacco plant from soil via the roots and accumulates in the leaves, especially where phosphate-rich fertiliser has been used.
Why is Polonium-210 in cigarettes?
Phosphate-rich fertilisers contain natural traces of radium-226, which through radioactive decay becomes polonium-210. Tobacco leaves bind these traces via sticky trichomes (tiny hairs on the leaf surface). When burned, polonium isn't destroyed — it partly enters the smoke, partly the ash. US National Cancer Institute studies estimate a pack-a-day smoker receives a dose over 20 years equivalent to several hundred chest X-rays.
What Polonium-210 does to your body — short term
The radioactive load per cigarette is measurable but so small it causes no noticeable acute symptoms. The damage is purely stochastic: alpha radiation strikes DNA regions in bronchial cells and triggers mutations. A single cigarette may statistically have no effect — but the sum over tens of thousands of cigarettes over years measurably alters cancer risk.
What Polonium-210 does long term
Polonium-210 is classified by IARC as a Group 1 carcinogen (alpha-emitting radionuclides). Alpha radiation acts preferentially at the site of deposition — that is, in the bronchial bifurcations where tar particles also accumulate. Lung cancer in precisely these regions is statistically typical of smokers' lungs. Some studies (Radford & Hunt, NEJM 1964) attribute a measurable share of smokers' lung cancer risk directly to polonium-related radiation exposure.
Where else do you know Polonium-210 from?
Polonium-210 became globally known in 2006 as the substance used to poison former Russian intelligence agent Alexander Litvinenko in London — he died within three weeks. Industrially, Po-210 is used in anti-static brushes for sensitive electronics and was a component of the trigger device in early atomic bombs. In consumer products it's restricted or banned in most countries.
How it compares
For polonium-210 there's no classical workplace concentration limit — radioactive substances are regulated via annual dose limits (Radiation Protection Ordinance). The radioactive load from tobacco smoke is estimated by EPA to be in the range of several hundred chest X-ray equivalents over a lifetime of smoking.
Workplace exposure limit: keine Konzentrationsgrenze — Jahresdosisgrenze gilt (StrlSchV)
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