MU Science Blog

Taking a Radioactive Drag: Polonium 210 and Cigarettes March 3, 2011

Radioactive Smoke: A Dangerous Isotope Lurks in Cigarettes

The Unknown and Known Dangers of Smoking

Many of us know the dangers of smoking. We see many friends and loved ones diagnosed with cancer and know of many who die from it each year. We have seen the warning labels on cigarette packages, but what is actually in that smoke? Research says, it’s polonium-210, a radioactive isotope found in fertilizers. The problem is, tobacco companies knew about this, a while ago. According to a 2011 article in Scientific American, “The tobacco industry has known about polonium in cigarettes for nearly 50 years.” Facts like these are disconcerting on many levels.

A Tobacco Plant

Ways We Are Exposed to Polonium 210

How exactly this isotope gets into the tobacco leaf is not entirely known, but it is thought to be a “daughter isotope” of uranium 238 found in fertilizers. When the fertilizer is spread on the soil, it begins to decay into either an airborne isotope, such as radon 222, or into lead 210 in the soil. Both of these products enter through the roots or into the leaves and eventually decay into polonium 210. The leaves are then processed normally and eventually end up in cigarettes.

The History of Polonium 210 Detection

Now, then, there seems to be a problem. See, polonium 210 was detected first in the 1960s. This should be a BIG problem, because we are now considering its dangers even though it has been known about  for 50+ years! Through a series of papers published during the 1960s, namely a paper published in 1964 by Radford and Hunt, scientists demonstrated how polonium 210 can enter the soil.  Subsequently in a paper published in 1974, by John B. Little and William O’Toole, proved that smokers can develop “hot-spots” on their lungs where polonium 210 accumulates. The hot spots can cause mutations due to alpha decay . The problem is, tobacco farmers and cigarette manufacturers are not removing this isotope. The good news is… they may start doing so soon.

How much polonium do we get when we smoke?

Here is an excerpt from a New York Times article:

A fraction of a trillionth of a curie (a unit of radiation named for polonium’s discoverers, Marie and Pierre Curie) may not sound like much, but remember that we’re talking about a powerful radionuclide disgorging alpha particles — the most dangerous kind when it comes to lung cancer — at a much higher rate even than the plutonium used in the bomb dropped on Nagasaki. Polonium 210 has a half life of about 138 days, making it thousands of times more radioactive than the nuclear fuels used in early atomic bombs.

We should also recall that people smoke a lot of cigarettes — about 5.7 trillion worldwide every year, enough to make a continuous chain from the earth to the sun and back, with enough left over for a few side-trips to Mars. If .04 picocuries of polonium are inhaled with every cigarette, about a quarter of a curie of one of the world’s most radioactive poisons is inhaled along with the tar, nicotine and cyanide of all the world’s cigarettes smoked each year. Pack-and-a-half smokers are dosed to the tune of about 300 chest X-rays.

Is there any relief?

Maybe we should stop smoking, it’s likely the best approach. If you can’t quite kick the habit, the FDA may help. Recently the FDA has taken over the regulation of cigarettes in the wake of the Family Smoking and Tobacco Control Act passed in 2009. With the FDA’s help, the exact content of polonium 210 in cigarettes may soon be published. On a side note, one quick fix may come in tobacco leaf preparation. Simply washing the leaves after harvest may eliminate a large portion of the polonium 210 found in the air.

The Largest Preventable Cause of Death in the World.

It seems like a radioactive isotope found in smoke is just one of many carcinogens that continue to contribute to tobacco being the largest preventable cause of death in the world. According to Scientific American:

The World Heath Organization has made clear that smoking is the most avoidable cause of death. It estimates that 1.3 million people die of lung cancer worldwide every year, 90 percent because of smoking. If polonium has been reduced through methods known to the industry, many thousands of those deaths could have been avoided. The industry, many thousands of those deaths could have been avoided. The industry’s lawyers made the conscious choice not to act on the results of their own scientists’ investigations. But it is the customers who have had to live with-and die from- that decision.

So, cigarettes are bad, but how bad they may be for us is still up in the air. Perhaps we can make them a little less dangerous in the future by removing these dangerous isotopes. Hopefully, with the FDA regulating cigarettes, this dangerous vice will soon be put to rest.