South China Morning Post — 27 March 2011
There has been public concern that the contamination of the environment by the Fukushima nuclear power plants may extend to eastern and southern China, including Hong Kong.
While the radiation hazard created by the earthquake damage in Japan is an emergency, it is important we take a consistent and comprehensive approach to the prevention of cancer due to radiation.
It has been reported since the 1960s that tobacco smoke contains the radioactive element polonium-210 ({+2}{+1}{+0}Po), and this isotope emits high-energy alpha radiation which causes cancer.
It has been documented that the tobacco industry has unsuccessfully tried to remove {+2}{+1}{+0}Po from tobacco products over more than 40 years.
A detailed review of the scientific literature on {+2}{+1}{+0}Po in tobacco was published in the American Journal of Public Health in 2008, titled “Waking a Sleeping Giant: The Tobacco Industry’s Response to the Polonium-210 Issue”.
This review points out that smokers of 1.5 packs of cigarettes a day are exposed to as much radiation as they would receive from 300 chest X-rays a year.
The presence of {+2}{+1}{+0}Po in tobacco plants is the result of farmers enhancing the tobacco flavour by repeatedly applying phosphate-rich fertiliser produced from phosphate rock.
The rock contains natural radium isotopes which decay to {+2}{+1}{+0}Po.
This polonium isotope is known to be completely volatile at the temperature of a burning cigarette.
Alpha particle radiation is emitted from {+2}{+1}{+0}Po and carried by fine particles in tobacco smoke. While there are many cancer causing chemicals in tobacco smoke, the accumulation of this radioactive material in the lungs of smokers is also capable of damaging the tissues in the respiratory system in a way which leads to lung cancer.
It is vitally important that all avoidable exposure to radioactive and other agents responsible for cancer is prevented. We can begin by ensuring that:
- Smokers are helped to quit by providing effectively funded, staffed and distributed smoking cessation services;
- Children are not enticed to smoke by tobacco companies; and
- Everyone is protected from breathing second-hand tobacco smoke.
Lai Hak-kan, honorary assistant professor, school of public health, University of Hong Kong