Radon, a great health risk

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Introduction
01 Cancer
02 Ozone
03 Urban air
04 Air pollutants
05 Blue-green algae
06 Water mutagens
07 Contamination
08 Chernobyl
09 Radon
10 Medical geology
11 Renal hazards
12 Organohalogens
13 Estrogens
14 Food hazards
15 Mycotoxins
16 Poisoning
17 Genetics
18 Risk

Ordering

(Excerpt from Chapter 9)

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Radon

Radon is alleged to be the second most important risk factor for lung cancer after smoking. There is radon nearly everywhere, even in our homes. From atomic bomb survivors we know that radioactive exposures increase the risk of other cancers, for example leukemia. What do we know about domestic radon exposure?

Ionizing radiation

Radioactive elements decay with different time constants or half-lives. During decay they may emit radioactivity. There are several kinds of ionizing radiation. In this context, we can limit ourselves to alpha-, beta- and gamma-radiation. The two first are so called particle radiation. alpha-radiation represents a considerable mass corresponding to the Helium nucleus with two protons and two neutrons, while beta or electron-radiation is about 10,000 times smaller in mass. gamma-radiation, on the other hand, represent electromagnetic energy of a certain wavelength and energy. These different kinds of radiation can all give rise to ions. They have different qualities and carry different health risks. alpha-radiation cannot penetrate very far, typically 0.05 mm in biological tissue or 5 cm in air, due to the large mass, but ionizes densely. It cannot penetrate a paper and most of it is stopped by the cornified (the dead cells) layer of the skin. beta-radiation penetrates longer, typically 5 mm in biological tissue, and can give rise to burn injuries of the skin. gamma-radiation penetration is highly dependent on energy, i.e. wavelength. It is used for X-ray examinations and can penetrate the human body. Any damage depends on the interaction between radiation and living cells.

Natural sources of radioactivity

The general population is exposed to radiation from natural radioactive nuclides. The most important are potassium-40, nuclides of the uranium and thorium series. The annual effective dose per person from potassium in the body is 0.2 mSv (millisievert), cosmic radiation 0.3 mSv, nuclides of the uranium and thorium series 0.5 mSv on average as external gamma-radiation in Finland and Sweden. Domestic radon accounts for an annual effective dose of 2 mSv from inhalation at 100 Bq/m³ (average in Sweden and Finland). Radon contributes up to two-thirds of the dose from natural sources.

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Magnus Svartengren, MD 1983, Ph.D., Environmental Hygiene 1986, Qualified specialist in Occupational & Environmental Medicine. He works at department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden. Research interests are gene environmental interaction, allergy & airways disease.