The Radioactive Polonium In Tobacco Leaves
For fifty years the tobacco industry have known that cigarettes contain a dangerous isotope called Polonium 210. Knowing this fact the industry could have easily removed it but they did nothing and allow it to remain in the cigarettes exposing millions of smokers to this deadly radioactive material. The Food and Drug Administration (FDA) now has the authority to force these companies to remove or reduce the level of this component in tobacco leaves thanks to a bill signed into law by President Obama in 2009.
Where Does Polonium 210 Comes From?
Polonium 210 comes from the fertilizer used to grow tobacco and other plants on farms. It is also absorbed by the leaves from the air around the plants at ground level. Polonium 210 is one of the many decay products of uranium 238, which occurs naturally in the soil but is found in a much higher concentration in phosphate rocks used to make fertilizers. Uranium 238 decays to lead 210 in the soil and is absorbed into the tobacco leaves through the roots and is later converted into polonium 210. As I mentioned before, the other way polonium 210 gets into the leaves is from the air from radon 222. It is another decay product of uranium 238 and it exists as a gas. The gaseous radon 222 then converted to lead 210, which eventually settles on the leaves and is later converted to polonium 210.
When the smoke from the leaves is inhaled it settles in “hotspots” in the lungs and can cause lung cancer. However, polonium 210 is not the main carcinogen or cancer causing agent in smoke. There are hundreds of other carcinogens present in cigarette smoke that causes thousand of deaths every year from smoking.
Polonium 210 As A Murder Weapon
The public first heard about polonium 210 as a murder weapon when it was mentioned in a news report broadcasted in 2006. The broadcast stated Litvinenko a former KGB operative has died in a London hospital due to acute radiation syndrome. It was later determined he was murdered with the deadly radioactive isotope called polonium 210. Investigators at the time never determined how Litvinenko was exposed to the polonium 210 isotope and as a result there were many theories circulating at the time how it happened including the one that the Russian government killed him. Nonetheless, polonium 210 must be ingested or it had to come in direct contact with Litvinenko to kill him since polonium is an alpha particle emitter. I will explain what an alpha particle emitter is in more detail later.
Unfortunately, this deadly element is found in small amounts in the tobacco leaves harvested for the manufacturing of cigarettes. People worldwide smoke more than six trillion cigarettes a year and each cigarette delivers a small amount of this substance into the lungs of smokers. If a typical smoker puffs one and a half packs of cigarettes a day the amount of polonium 210 deposited in his lungs will give off the amount of radiation equivalent to 300 chest x-rays a year.
The Accidental Discovery of Polonium 210 in Cigarettes
It was discovered by accident that polonium 210 was accumulating in the lungs of smokers. In the 1960s radiation and radioactive fallout was the hottest topic in the scientific community. Radioactivity was a major theme in many sci-fi movies at the time so obviously there was a lot of research going on about it. A radiochemist Vilma E. Hunt at the Harvard School of Public Health develop a technique for measuring low levels of radium and polonium, and around 1964 she decided to try her measuring device on cigarette ashes. She was surprised that there was no detection of polonium in the ashes since small amount of polonium 210 is found in background radiation and in all organic material, specifically plants. All animals have low levels of polonium 210 since we are all part of the large food chain including the plant-eating (herbivores) animal. The question was where did the polonium go? She then realized that the polonium in the tobacco went up in smoke. Vilwa confirmed her conclusion by measuring the level of polonium in the smoke. The results were conclusive.
As a result, other scientist at the school began studying polonium both in the cigarettes and in the lungs of deceased smokers. It was determined from the studies that polonium accumulated in specific spots in the lungs at the points of bifurication or branching. These spots are called “Hot Spots” of radioactivity where polonium 210 emitted alpha particles. Alpha particles are the weakest form of radioactivity. A sheet of paper can easily stop these particles and they cannot penetrate the skin surface. This is why radioactive polonium and even plutonium (mainly an alpha emitter) do not do any harm to you until it is ingested, especially by inhalation, into your body. This is why the Japanese authorities had to evacuate an area of more than 50 miles from the plants because they were concerned that the gaseous plutonium will travel that far from the site. As a matter of fact, you can hold these radioactive materials in your hands with gloves on them without any serious harmful effects. On the other hand beta and gamma particles are more penetrating and will do harm to biological tissues.
The President Steps In To Change Things
Since the tobacco industry knew about the presence of polonium 210 in tobacco leaves these are the steps they could have taken to reduce it presence in the leaves. For starters, chemicals could have been added to cigarettes to prevent the polonium 210 from vaporizing so the smokers will not inhale it. The tobacco growers could have switch to low-uranium fertilizer. The leaves could have been washed before harvesting the tobacco. An ion-exchange filter could have been put on the cigarettes to block the polonium and finally, they could have genetically engineer the tobacco plant to have “hairless” leaves so that that the leaves will not capture the polonium converted from the captured lead particles.
Unfortunately, the tobacco industry did not perform these steps because they did not have to since the government did not regulate it. Some of these steps were quite simple to do and obviously we can see why they did not perform them. Thousands of people have lost their lives because the industry wanted to keep this process of reducing the polonium level a secret.
The situation is now changing for cigarette smokers since President Obama signed the "Family Smoking Prevention and Tobacco Control Act" into law in 2009. This law places the tobacco industry under the control of the FDA allowing the agency to regulate the cigarette manufacturing process. The law also forces the tobacco companies to remove the polonium from the cigarettes thus reducing the number of deaths from cigarette
In the 1990s historic lawsuits brought against the tobacco companies by 46 states force them to admit that smoking is dangerous and additive, and resulted in the release of millions of internal documents. These documents showed that the tobacco companies knowingly held all the research results and facts about polonium in tobacco leaves. The companies knew if this information have gotten out there would have been a very serious monetary damage to them despite the fact that Vilma Hunt and other scientists outside the tobacco circle had published their research in 1964. Unfortunately, the general public did not see these documents published in the scientific journals until the damage has already been done years later.
© 2011 Melvin Porter