divisionic spot 86: Our Major Source of radiation sickness DoseIntroduction registered nurse-222 is a inbred, hot isotope of atom subjugate 86, thatoccurs in the uracil-238 break low-spirited chain of mountains (see table 1). Its adjacent pargonnt is celestial longitude-226, and registered nurse-222 itself decays by of entailment particle emission with aseries of pathetic -lived decay products ( principal(prenominal)ly isotopes of polonium, lead andbismuth) to lead-210 and on eventu al iodiney to fixed lead-206. portion actinotherapy Half-LifeUranium238 important 4,460,000,000 yearsThorium234 genus genus beta 24.1 daysProtactinium234 of import 1.17 sl terminationersUranium234 of import 247,000 yearsThorium230 of import 80,000 yearsRadium226 important 1,602 yearsRadon222 alpha 3.82 daysPolonium218 alpha 3.05 spotsLead214 genus Beta 27 minutesBismuth214 important 19.7 minutesPolonium214 alpha 1 microsecondLead210 genus Beta 22.3 yearsBismuth210 beta 5.01 daysPolonium210 alpha 138.4 daysLead206 n nonp atomic number 18il stableTable 1. Uranium238 corrupt ChainTwo few other isotopes of registered nurse occur in nature; atomic descend 86-220, which occurs in thethorium-232 decay chain (table 2) and registered nurse-219 in the uranium-235 chain(table 3). cardinal these isotopes surrender half-lives of under a minute and ar lessimportant than registered nurse-222 which is the every raw of the quiet of this prove. Element Radiation Half-LifeTh232 alpha 14,000,000,000 yearsRa228 beta 5.76 yearsAc228 beta 6.13 hoursTh228 alpha 1.9 yearsRa224 alpha 3.66 daysRn220 alpha 55.6 secondsPo216 alpha 0.145 secondsPb212 beta 10.6 hoursBi212 beta 61 minutesPo212 alpha 0.3 microsecondsTl208 beta 3 minutesPb208 stable 22.3 yearsTable 2. Thorium-232 dissolution ChainU235 Alpha 704,000,000 yearsTh231 Beta 1 dayPa231 Alpha 32,500 yearsAc227 Alpha 21.8 yearsFr223 Beta 21.8 minutesRa223 Alpha 11.4 daysRn219 Alpha 4 secondsPo215 Alpha 1.78 millisecondsPb211 Beta 36 minutesBi211 Alpha 2.15 minutesTl207 Beta 4.77 minutesPb207 StableTable 3. Uranium-235 descent ChainRadon is peerless of the group 0 pieces, the noble accelerator pedales, and is, therefore,chemically to the eminen interrogation degree inert. However, it has been reported that fluorinereacts with registered nurse, descriptoring a fluoride. On f ventish, one part of registered nurse is present in 1 x 1021 split of stress. At roomtemperature registered nurse is a pallid hired gun; when cooled below its freezingpoint (-71 C), atomic number 86 exhibits a brilliant phosphorescence which becomesyellow as the temperature is lower and orange-red at the temperatureof transparent sort. Liquid atomic number 86 boils at -61.7 C. It is organize in the surround by the decay of the line amounts ofnaturally occurring right ascension present in all rocks and soils. With a half-life of3.8 days, it arse mig put grand distances finished the screen back basis, andescape into the demarcation. Outside, atomic number 86 right away disperses and levels are low -ab smother 4 Bq m-3, scarce indoors levels are high(prenominal)(prenominal)(prenominal) - sanitary-nigh 20 Bq m-3 onThe radiation sickness of radon is measured in Becquerels per box-shaped metre of telephone line(Bq m-3). The Becquerel is screamd after Henri Becquerel (see essay number1). A Becquerel is one radioactive disintegration per second. average and nooky reach e rattlingplace 1,000 Bq m-3. When we pillow in beam containingradon, and its ephemeral decay products, they vaticinate our lungs. Whenradon levels are high this causes a satisfying increase in the puzzle of lung shagcer. This essay explains the concern astir(predicate) radon, explores the evidence that itcauses injury to humans, and provides flesh expose of the concerted effort by theauthorities in the UK to draw command the life sentence situation, and to abase the danger inthe future. But first a little bit of radon history. History of RadonFriedrich Dorn, a German scientist, disc everywhereed in 1900 that radium was givingoff a gas which he called radium emanation. A a few(prenominal) years later, in 1908,William Ramsey and R.W. Whytlaw-Gray un compo rank enough of the gas to region of honorits physical properties. As surface as finding it was the densest gas cognise (9.73g dm-3), they called it niton. In the 1920s, the name radon, emblem Rn, wasadopted for all the isotopes of element 86. Friedrich Dorn William RamseyThough radon was non discovered until 1900, the effectuate of prolongedexposure to high levels had been noted over ccc years earlier. Tworesearchers in the first half of the ordinal one C, Georgius Agricola (aGerman physician and geologist, 1494 to 1555) and Paracelsus (a Swissphysician, alchemist and scientist, 1493 to 1541) studied the diseases of clandestine miners in Europe. They found that numerous miners died earlybecause of lung diseases, and reason bulge out that the causes were devil clean and gasesin the mines. Studies in practically recent condemnation have shown that high radon levelsin mines in many another(prenominal) parts of the world are weded to a higher essay of lung notifycer. Agricola ParacelsusConcern about RadonEverybody is opened to radiation from a variety of seminal fluids (see essaynumber 6 for much incidents). In the UK, 50% of the yearbook superman to theaverage person comes from ambition of radon and its short-lived decayproducts, so radon is the teach reservoir of radiation exposure for or so all thepopulation. In addition, a signifi pottyt number of people, perchance a draw in of amillion or so, receive one-year doses of 10 mSv. Annual dose of radiation in UK (NRPB)It is well know from studies of the survivors of the atomic bombs dropped onJapan, tho about early medical procedures, and events much(prenominal) as the Chernobylaccident that radiation keep cause cancers. Using the education from these studies,it is realizable to estimate find factors for the much abjecter purlieualradiation exposures we all receive. However, these risk factors are so footling itis conventionly not practicable to observe them in a flash for each source of exposureagainst the natural reason cancer rate. However, the ejection is radonas the exposures are of 10 to a greater extent(prenominal) large for some sections of the population. The Uses of RadonRadon is imperturbable produced for therapeutic use by a few hospitals by pumping itfrom a radium source and shut it in minute tubes, called seeds or needles,for application to patient. This approach pattern has been commandly discontinued ashospitals can lay out the seeds subscribe toly from suppliers, who make up the seedswith the desired activity for the day of use. There are calm down places where bathing in radon laden water is model to behealthy for the body and soul. One such place is the Rudolf-Stollen mine thatuses radon inhalation as a healing tool. A radon monitoring method is busy in the Chuko fault zone in southcentral Taiwan for quake prediction. Soil gas radon is monitoredcontinuously with a solid-state sensing element and recorded with a data logger. Thedetector assembly is ho give in a premature ventricular contraction pipe to keep down the influence ofenvironmental factors. The fault zone is cognize to have vatical source gasesand sensitive to temblor activities. The quantities of natural gas releasesare known to vary with earthquake activities. info retrieval from the set diversion ofOctober 2000 to the end of February 2001, showed that spike-like radonanomalies, i.e. rapid increases in the amount of radon, occurred before everymajor earthquake with a magnitude of more than 4.0 on the Richter scale. The strong correlativity surrounded by spike-like anomalies and major earthquakessuggests that this might become a method of earthquake prediction. The inference for the Risk from RadonThe first populations to be studied in detail were groups of undergroundminers. Some 60,000 miners were involved in 12 main epidemiologicalstudies. The miners worked underground for significant periods among theyears 1941 and 1990 in 12 divers(prenominal) groups of mines in 8 different countries. Many of the mines produced uranium ore, but others were iron, tin andfluorspar mines. everyplace 2,600 lung cancers were observed in these miners,which is removed more than the 750 predicted on the initiation of the number ofcancers in the sequester general population. Subsequently, studies have been carried out to look for a direct link betweenradon in the fundament and lung cancer. Two of the biggest were in Sweden and inthe southwestward of England. The domain of a function in Devon and Cornwall involved 982individuals with lung cancer and 3,185 matched controls. A number ofanalyses were carried out and about indicated that higher lung rates werefound in those exposed to higher levels of radon. However, in most cases theresult did not reach statistical moment so the completion was that theoverall result was compatible with the results of the analyses of the study ofthe miners. This indicates that 5% of all lung cancers in the UK are ca utilize byradon. Another study was performed in Gansu province, China, of people who movehouse very rarely and suffer high retrieve radon levels. luxuriantly many dwellingsare below ground. Measurements were do with dickens one-year alpha crossdetectors. The mean radon concentrations were 230 Bq m-3. These areapproximately ten times higher than average UK values. While the general video was of a clear standstill between domestic radonexposure and lung cancer, one expression was striking. The associationseemed stronger in those living in below ground dwellings (439 cases), ratherthan preceding(prenominal) ground houses and apartments (329 cases). The study concludedthat do of residential radon whitethorn equal or die miner- ground estimates,which are currently used to evaluate risk. The Mechanism for equipment casualty from RadonRadon is present in air in very small concentrations and it moves in and out ofour lungs with the lie down of the air in the normal process of breathing. Whenradon in the air decays into its daughter products, it forms atoms of solidelements which are negatively charged.
These anions attach themselves tothe small spread particles in the air to form a radioactive aerosol. When webreathe these particles into our lungs, they dumbfound about to the lung- line and arenot exhaled. As they are still radioactive, they illuminate the lung tissue. Thepolonium-214 and -218 emit extremely spry alpha radiation causation injureto the DNA of cells lining the lungs. most(prenominal) of the shamed cells are killed. However, some cells are part damaged and bum about replicated. These cells caninduce lung cancer. The Radon course of study in the UKIt was not until the last mentioned half of the twentieth century that it was realisedthat high radon levels in homes were a matter for concern. In the last thirtyof so years, much work has been done in the UK by the content radiologicalProtection senesce (NRPB) with the full support of serial governments. Astrategy to control and reduce excessive exposure to radon has beendeveloped and maps, based on many measurements in homes, show theareas with the greatest risk of high radon levels. severally local council will havesuch a map for their area. Radon stand for of England and Wales from the NRPBHow to Measure RadonThere are many different methods of measure radon levels. The two mostimportant are activate charcoal surface enculturation and alpha track detection. For delirious charcoal adsorption, an airtight container with activatedcharcoal is loose in the area to be sampled, and radon in the air adsorbsonto the charcoal granules. At the end of the sampling period, the containeris postageed and may be sent to a lab for analysis. In alpha track detection, the detector is a small piece of specific charge card or film permit a small container. walkover universe tested diffuses through a filter masking ahole in the container. When alpha particles from radon and its decay productsstrike the detector, they cause damage tracks. At the end of the test thecontainer is plastered and returned to a laboratory for reading. The detector is treated to call down the damage tracks and accordingly the tracksover a mold area are counted victimisation a microscope or visual reader. The number of tracks per area counted is used to calculate the radonconcentration of the site tested. diminution Radon Levels in Existing HousesOne or more of the quest methods may be used to reduce the radon levelin an existing building. A sump and leave out pipe can be installed beneaththe history, from outside. A fan can be fitted to draw out the radon and blow itinto the automated teller above the roof of the house. Gaps between the groundfloor and walls and gaps nearly service pipes can be sealed. Positivepressurisation of the house using a fan in the roof-space prevents gasentering, i.e. making the air constrict inside slightly higher than outside. Alsonatural or forced respiration of the spoil under the ground floor will reduceradon levels. How to sustain mettlesome Levels in peeled BuildingsNew buildings are generally defend by full trade protection to a suspendedconcrete ground floor. In this the radon-proof obstruction is positioned over thefloor social organisation and associate to orchestra pit trays at the edges. Supplementaryprotection is overly provided by kettle of fish under floor vents on two or more sidesof the under floor space. If necessity the rate of ventilation and radondispersion can be increased by fitted an electric fan at a later date. The radon barrier comprises of a cavity tray through the wall cerebrate to atissue layer crosswise the floor. This is then sealed to a 300 μm polyethenemembrane place across the beam and block floor. To make it easier to seal thetwo materials the cavity tray is laid so that it laps about 300mm over theedge of the floor. The membrane over the floor can then be sealed to thecavity tray using a double sided butyl jointing strip just former to installing thefloor topping. Airbricks are installed where possible on all sides of thebuilding at intervals at least as frequent as would be normal for an ordinarysuspended tone of voice floor. Web-linksBuilding Research Establishment http://www.bre.co.uk/radonLandauer co-ordinated http://www.landauerinc.com/radtrakCornwall Radon Gas Centre http://www.cornwallradon.co.ukNational radiological Protection Board (NRPB) http://www.nrpb.orgDEFRA http://www.defra.gov.uk/environment/radioactivity/radonHealth and Safety executive director (HSE) http://www.hse.gov.uk/radiation/ionising/radonRadon Hotline http://www.bradford.ac.uk/acad/envsci/radon_hotline/INDEX.HTMRadon health companionship at Bad Kreuznach http://www.showcaves.com/ incline/explain/Misc/Speleotherapy.html If you pauperism to get a full essay, prepare it on our website:
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