Among the variety of different types of cancer, one of the most common is lung cancer; the environment in which people live in the 21st century greatly contributes to the development of this type of cancer.
Concentration units[ edit ] Pb is formed from the decay of Rn. Here is a typical deposition rate of Pb as observed in Japan as a function of time, due to variations in radon concentration. One WLM is equivalent to 3. The levels of Pb can be measured. The rate of deposition of this radioisotope is dependent on the weather.
Ventilation regulations try to Thesis statement for lung cancer concentrations in uranium mines under the "working level", and under 3 WL pCi Rn per liter of air; Not all granitic regions are prone to high emissions of radon. Being a rare gas, it usually migrates freely through faults and fragmented soils, and may accumulate in caves or water.
Due to its very small half-life four days for Rnits concentration decreases very quickly when the distance from the production area increases. Its atmospheric concentration varies greatly depending on the season and conditions. For instance, it has been shown to accumulate in the air if there is a meteorological inversion and little wind.
Hence, ground water generally has higher concentrations of Rn than surface waterbecause the radon is continuously produced by radioactive decay of Ra present in rocks.
Likewise, the saturated zone of a soil frequently has a higher radon content than the unsaturated zone because of diffusional losses to the atmosphere. Because radon has a similar pressure and temperature curve as propane, and oil refineries separate petrochemicals based on their boiling points, the piping carrying freshly separated propane in oil refineries can become partially radioactive due to radon decay particles.
Residues from the oil and gas industry often contain radium and its daughters. The sulfate scale from an oil well can be radium rich, while the water, oil, and gas from a well often contains radon.
The radon decays to form solid radioisotopes which form coatings on the inside of pipework. In an oil processing plant, the area of the plant where propane is processed is often one of the more contaminated areas, because radon has a similar boiling point as propane.
Indoor radon concentration is usually assumed to follow a lognormal distribution on a given territory. The so-called Watras incident named after the American construction engineer Stanley Watrasin which an employee at a U.
Iowa has the highest average radon concentrations in the United States due to significant glaciation that ground the granitic rocks from the Canadian Shield and deposited it as soils making up the rich Iowa farmland.
In a few locations, uranium tailings have been used for landfills and were subsequently built on, resulting in possible increased exposure to radon. Though at the time radon itself was not understood to be the cause—indeed, neither it nor radiation had even been discovered—mineralogist Georg Agricola recommended ventilation of mines to avoid this mountain sickness Bergsucht.
Beyond mining in general, radon is a particular problem in the mining of uranium ; significant excess lung cancer deaths have been identified in epidemiological studies of uranium miners and other hard-rock miners employed in the s and s.
Radon resulting from the high radium content in uncovered dumps and tailing ponds can be easily released into the atmosphere. Because radon is a product of the radioactive decay of uranium, underground uranium mines may have high concentrations of radon.
Many uranium miners in the Four Corners region contracted lung cancer and other pathologies as a result of high levels of exposure to radon in the mids. The increased incidence of lung cancer was particularly pronounced among Native American and Mormon miners, because those groups normally have low rates of lung cancer.
The cases reported in these miners cannot be attributed solely to radon or radon daughters but may be due to exposure to silica, to other mine pollutants, to smoking, or to other causes.
Because radon and cigarette smoke both cause lung-cancer, and since the effect of smoking is far above that of radon, it is complicated to disentangle the effects of the two kinds of exposure; misinterpreting the smoking habit by a few percent can blur out the radon effect.
In recent years, the average annual exposure of uranium miners has fallen to levels similar to the concentrations inhaled in some homes. This has reduced the risk of occupationally induced cancer from radon, although it still remains an issue both for those who are currently employed in affected mines and for those who have been employed in the past.The Online Writing Lab (OWL) at Purdue University houses writing resources and instructional material, and we provide these as a free service of the Writing Lab at Purdue.
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