Radium and radon in the environment 5321285 215643686 2008-05-29T02:12:12Z 67.171.214.234 Fixed a typo ("beloynd all reasonable doubt" to "beyond all reasonable doubt"). {{cleanup|date = December 2007}} This is a subpage of [[Environmental radioactivity]]. {{Pollution}} == Radium == === Radium in quack medicine === See the story of [[Eben Byers]] for details of one very nasty case which involved a product called [[Radithor]] which contained 1 mCi (40 MBq) of <sup>226</sup>Ra and 1 mCi of <sup>228</sup>Ra per bottle. Radithor was taken by mouth and as radium is a [[calcium]] mimic it has a very long [[biological halflife]] in [[bone]]. === Radium in the oil/gas industry === Residues from the [[Petroleum|oil]] and [[natural gas|gas]] industry often contain [[radium]] and its daughters. The sulfate scale from an oil well can be very radium rich. It is the case that the water inside an oil field is often very rich in [[strontium]], [[barium]] and [[radium]] while seawater is very rich in [[sulfate]] so if water from an oil well is discharged into the sea or mixed with seawater the radium is likely to be brought out of solution by the barium/strontium sulfate which acts as a [[carrier]] precipitate. === Glow in the dark products (radioluminescent) === Local contamination from radium based [[Radioluminescence|radioluminescent]] paints having been improperly disposed of is not unknown. [http://www.epa.gov/region02/superfund/npl/0200772c.pdf] == Radon == The majority of the dose is caused by the decay of the [[polonium]] (<sup>218</sup>Po) and [[lead]] (<sup>214</sup>Pb) daughters from <sup>222</sup>Rn. It is the case that by controlling the daughters that the dose to the [[skin]] and [[lung]]s can be reduced by at least 90%. This can be done by wearing a dust mask, and wearing a suit to cover the entire body. Note that exposure to [[smoke]] at the same time as [[radon]] and radon daughters will increase the harmful effect of the radon. In [[uranium mining|uranium miner]]s radon has been found to be more [[carcinogenic]] in [[smokers]] than in non-smokers. === Occurrence of radon === On average, there is one atom of radon in 1 x 10<sup>21</sup> molecules of air. Radon can be found in some [[spring (water)|spring water]]s and [[hot spring]]s. The towns of [[Misasa, Tottori|Misasa]], [[Japan]], and [[Bad Kreuznach]], [[Germany]] boast radium-rich springs which emit radon. Unsurprisingly, [[Radium Springs, New Mexico]] does too. Radon exhausts naturally from the ground, particularly in certain regions, especially but not only regions with [[granite|granitic]] soils. Not all granitic regions are prone to high emissions of radon, for instance while the rock which [[Aberdeen]] is on is very radium rich the rock lacks the cracks required for the radon to migrate. In other near by areas of Scotland (to the north of Aberdeen) and in [[Cornwall]]/[[Devon]] the radon is very able to leave the rock. Radon is a decay product of [[radium]] which in turn is a decay product of uranium. It is possible to get maps of average radon levels in houses, these maps assist in the planning of radon mitigation measures for homes.[http://eetd.lbl.gov/IEP/high-radon/USgm.htm] [[Image:USradonmapforhouses.jpg|400px|Average radon levels in homes]] Note that while high uranium in the [[soil]]/[[Rock (geology)|rock]] under a house does not always lead to a high radon level in air, a positive correlation between the uranium content of the soil and the radon level in air can be seen. [[Image:Uraniumdisstribution.jpg|400px|Uranium concentration in US soils]] === Radon in air === Radon is related to [[Indoor air quality]] as it blights many homes. (See "Radon in Houses" below.) The radon (<sup>222</sup>Rn) released into the air decays to <sup>210</sup>Pb and other radioisotopes, the levels of [[lead|<sup>210</sup>Pb]] can be measured. It is important to note that the rate of deposition of this radioisotope is very dependent on the weather. Here is a graph of the deposition rate observed in [[Japan]] (M. Yamamoto ''et al.'', ''Journal of Environmental Radioactivity'', 2006, '''86''', 110-131). [[Image:Lead210inairatjapan.png|500px|center|Lead-210 deposition rate as a function of time as observed in Japan]] === Radon in water === Well water can be very radon rich, the use of this water inside a house is an additional route allowing radon to enter the house. The radon can enter the air and then be a source of exposure to the humans, or the water can be consumed by humans which is a different exposure route. === Radon in the oil/gas industry === 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 of the plant as radon has a similar boiling point as propane.[http://www.enprotec-inc.com/Presentations/NORM.pdf] === Radon in mines and caves === Because uranium minerals emit [[radon]] gas, and their harmful and highly radioactive [[decay product|daughter products]], uranium mining is considerably more dangerous than other (already dangerous) [[Underground mining (hard rock)|hard rock mining]], requiring adequate ventilation systems if the mines are not [[open-pit mining|open pit]]. During the 1950s, a significant number of American uranium miners were [[Navajo Nation|Navajo]] Indians, as many uranium deposits were discovered on Navajo [[Indian reservation|reservations]]. A statistically significant subset of these miners later developed [[small-cell lung cancer]], a type of cancer usually not associated with smoking, after exposure to uranium ore and [[radon]]-222, a natural decay product of uranium.[http://www.chestjournal.org/cgi/content/abstract/81/4/449] The radon, which is produced by the uranium, and not the uranium itself has been shown to be the cancer causing agent. [http://www.rand.org/pubs/monograph_reports/MR1018.7/mr1018.7.chap2.html] Some survivors and their descendants received compensation under the [[Radiation Exposure Compensation Act]] in 1990. Currently the level of radon in the air of mines is normally controlled by [[law]]. In a working mine, the radon level can be controlled by [[Ventilation (architecture)|ventilation]], sealing off old workings and controlling the water in the mine. The level in a mine can go up when a mine is abandoned, it can reach a level which is able to cause the [[skin]] to become [[red]] (a mild [[radiation burn]]). The radon levels in some of the mines can reach 400 to 700 kBq m<sup>-3</sup>. A common unit of exposure of lung tissue to [[alpha]] emitters is the [[Working level month]] ('''WLM'''), this is where the human [[lung]]s have been exposed for 170 hours (a typical month worth of work for a miner) to air which has 3.7 kBq of <sup>222</sup>Rn (in equilibrium with its decay products). This is air which has the alpha dose rate of 1 working level ('''WL'''). It is estimated that the average person (''[[general public]]'') is subject to 0.2 WLM per year, which works out at about 15 to 20 WLM in a lifetime. According to the NRC 1 WLM is a 5 to 10 mSv lung dose (0.5 to 1.0 [[Röntgen equivalent man|rem]]), while the [[OECD]] consider that 1 WLM is equal to a lung dose of 5.5 mSv, the [[ICRP]] consider 1 WLM to be a 5 mSv lung dose for professional workers (and 4 mSv lung dose for the general public). Lastly the [[UN]] ([[UNSCEAR]]) consider that the exposure of the lungs to 1 Bq of <sup>222</sup>Rn (in equilibrium with its decay products) for one year will cause a dose of 61 μSv. This overview of the working level month is based upon the book by Jiří Hála and James D. Navratil (ISBN 80-7302-053-X). In humans a relationship between [[lung cancer]] and radon has been shown at exist (beyond all reasonable doubt) for exposures of 100 WLM and above. By using the data from several studies it has been possible to show that an increased risk can be caused by a dose as low as 15 to 20 WLM. Sadly these studies have been difficult as the random errors in the data are very large. It is likely that the miners are also subject to other effects which can harm their lungs while at work (for example dust and [[diesel]] fumes). Radon References A.R. Denman, J.P. Eatough, G. Gillmore and P.S. Phillips, Assessment of Health Risks To Skin and Lung Of Elevated Radon Level in Abandoned Mines, ''Health Physics'', 2003, '''85''', 733. G.K. Gillmore, P. Phillips, A. Denman, M Sperrin and G. Pearse, ''Ecotoxicology and Environmental Safety'', 2001, '''49''', 281. Radioactivity, ionizing radiation and Nuclear Energy, Jiří Hála and James D. Navratil, Chapter 8 (Radioactivity and ionizing radiation in the environment), ISBN 80-7302-053-X. J.H. Lubin and J.D. Boice, ''Journal Natl. Cancer Inst.'', 1997, '''89''', 49. (Risks of indoor radon) N.M. Hurley and J.H. Hurley, ''Environment International'', 1986, '''12''', 39. (Lung cancer in uranium miners as a function of radon exposure). === Radon in houses === The danger of radon exposure in [[dwellings]] was discovered in [[1984]] by Stanley Watras, an employee at the [[Limerick nuclear power plant]] in [[Pennsylvania]]. Mr. Watras set off the [[radiation]] alarms (see [[Geiger counter]]) on his way ''into'' work for two weeks straight while authorities searched for the source of the [[contamination]]. They were shocked to find that the source was astonishingly high levels of Radon in his [[basement]] and it was not related to the nuclear plant. The risks associated with living in his house were estimated to be equivalent to [[Tobacco smoking|smoking]] 135 packs of [[cigarette]]s every day.[http://www.bradford.ac.uk/acad/envsci/radon_hotline/radonstory.htm] Depending on how houses are built and ventilated, radon may accumulate in basements and dwellings. The [[European Union]] recommends that action should be taken starting from concentrations of 400&nbsp;[[Becquerel|Bq]]/m<sup>3</sup> for old houses, and 200&nbsp;Bq/m<sup>3</sup> for new ones. The [[National Council on Radiation Protection and Measurement]] ([[NCRP]]) recommends action for any house with a concentration higher than 8&nbsp;[[Curie|pCi]]/L (300 Bq/m³). The [[United States]] [[United States Environmental Protection Agency|Environmental Protection Agency]] recommends action for any house with a concentration higher than 148&nbsp;Bq/m<sup>3</sup> (given as 4&nbsp;[[Curie|pCi]]/L). Nearly one in 15 homes in the U.S. has a high level of indoor radon according to their statistics. The U.S. Surgeon General and EPA recommend all homes be tested for radon. Since 1985, millions of homes have been tested for radon in the U.S. By adding a crawl space under the ground floor, which is subject to forced ventilation the radon level in the house can be lowered.[http://www.p2pays.org/ref/07/06295.pdf] == Further reading == * Hala, J. and Navratil J.D., ''Radioactivity, Ionizing Radiation and Nuclear Energy'', Konvoj, 2003. ISBN 80-7302-053-X {{environmental science}} [[Category:Nuclear technology]] [[Category:Nuclear chemistry]] [[Category:Nuclear physics]] [[Category:Radiobiology]] [[Category:Radioactivity]] [[Category:Soil contamination]]