DOCSLIB.ORG

Determination of Americium and Curium Using Ion-Exchange in the Nitric-Acid-Methanol Medium for Environmental

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Determination of Americium and Curium Using Ion-Exchange in the Nitric-Acid-Methanol Medium for Environmental The combined eluant1 9MHC s containing americiu curiud man m are evaporated to dryness and the residue is dissolved into 20 ml 8M HNO_. The pH of the solution is then adjusted to 2.5 with ammonia and the solution is transferred to a 250 ml separatory funnel. Twenty five ml of HDEHP solution is added and Am is extracted to the organic phase by shaking vigorousl organiraine 2 Th r . yfo c phas washes ei d twic e0.075l witm 5 1 2 hMHC to remove extracted lanthanides and the aqueous phase is discarded. Americium is then back-extracted twice with 25 ml 12 M HC1 each time for 2 min. The aqueous phase combinee sar d evaporatedan concenf o l drynessm o t d-w fe A . trated HC1 are added to the residue and evaporated to dryness. This treatment is repeated several times. The Am thus separated is further purified by anion as well as cation exchange procedures from impurities, such as traces of Fe, Pu, U, Po and Th. This is done by passing the 9M HCl solution of the residue through a small column (<j» 5mm x 150 mm) containing floa Dowe f t o wml/inn5 a l rat0. x1 m f wel3 s Dowef eo . a o s la 0 l x5 m 2 The Am passes through the column while remaining traces of Fe, Pu, U and Po are sorbed on Dowex 1 and that of Th on Dowex 50. Although lanthanides in this medium eventually pass through the column, the speed of the passage is very much slower than that of Am. This difference in the speed of passage makes it possible to eliminate lanthanides from the Am fraction by limiting the volum washingf eo colume Th . washe s ni d wit columh2 n volumf eo HClM 9 . e electro-depositioTh purifiee th f no d plutoniud man americium fractions were performed by the procedure described by Talvitie . The effluent and washings from the plutonium separation were evaporated to drynes concentratef re-dissolved o san l m 6 0. n di d H-SO, americiue ;th m fractio evaporates nwa dryneso t d reconstituted san concentratef do witl m h1 d H-SO,. After heating to fumes of SO , 2 ml of H.O, 50 ml of 1M oxalic acid and 1 drop of 1 M DTPA (ammonium diethylamine-triamine penta acetic acid) is solutione addeth o t d . Several drop 0.02f so % thymol blue indicatos i r the adjustes additioy i b n H 5 p indicaton adde a *o 2. e t df s n o th a d d ran ammonium hydroxide. 4.2 Determinatio americiuf no curiud man m using ion-exchange nitric-acid-methanoe inth l mediu environmentar mfo l analysis E. Holm and R. Fukai While transplutonic element onle sar y slightly sorbe anioo t d n exchangers from hydrochloric or nitric acid media, the presence of alcohol enhances the anionic exchange of these elements, especially in nitric and 86 sulfuric solutions. Haidvogel et a.1, showed this enhancement by thin- 78 layer chromatography sorptioe th ; f transplutonino c elements increased with increasing alcohol bindine contenth d gtan wit ion-exchangee hth s rwa stronge nitrie th n cri medium tha sulfurie n th tha n i t c medium. Guseva 87,88 et al. separated americium from curium, both at relatively high levels, nitrie inth c acid-methanol mixture, observing thagreatee th t atomie th r c number, the stronger the sorption. In the present work a method has been developed for determining americium and curium in environmental samples, on the basis of the difference between the sorption characteristics to anion exchangers in the acid-methanol system of these transplutonic elements and those of plutonium, polonium and thorium. The method also permits us to perform sequential determinatio plutoniumf no , when necessary radiochemicae Th . l separatio americiuf no m from generallcuriut no s i m y required since modern 241 a-spectrometry resolve majoe sth rm (5.4 A a-pea9 f kMeVo ) from either 242 246 that of Cm (6.10 MeV) or Cm (5.80 MeV), which possibly co-exist with Am in environmental samples. The reagent separatioe s th use followss n a i d e nar : Nitric acid-methanol mixtures: 1M HNO -90% CH OH solution and 0,5M HN03-70% CH3OH solution. 1st anion exchange resin column: Dowe (X8x1 , 100-200 mesh) <f> 1cm, volum. ml 0 e1 2nd anion exchange resin column: Dowex 1 (X2, 50-100 mesh) <f> 1cm, volum. ml 0 e2 Cation exchange resin column: Dowex 50 (X8, 200-400 mesh) <j> 1cm, volume 5 ml. 241 Americium-243 solution: chemical yieldm A monito r rfo (5 dpm/m )O 1.n MHN li Plutonium-23 plutonium-24r 6o 2 solution: Chemical yield monitor 21J 8 91JyQ 9&u0 for °Pu and ^ '^ pu (5 dpn/ml in 1M HN03), Biologica sedimenr lo t sample driee sar 105-110°Ct a d , weighed and place porcelaia n i d n crucibl whico et yiele hth d determinantsw fe ,a f\ t n ty t\ £ /j r /) normalle ar , Pu y added r o u ,P Afte d ran dryindpm A m eacg f ho again samplee ,th ashee sar 500°t a d C overnight h obtaineas e leaches Th i d. d wit mixturha a mixturconcentratef eo e of wit1 additiow concente dHC fe th h HNO d a an _f rno milliliters of H (30%). 3+ Water samples are acidified, to which iron carrier (50mg Fe ) is added. The actinides are co-precipitated with Fe hydroxide by adding ammonia precipitate Th . centrifuges ei dissolved an d 9-1n i d 2 M HC1. After 79 the addition of a few drops of H~0 (30%), the solution is heated and kept at 80°C for 20 min. The acidity of the solution is finally adjusted to 9M HC1. After cooling, the solution is passed through the first colum theDowed f no an n x 1 throug Dowee hth column0 x5 , whic directls hi y connected with the first column, at a flow rate of 2ml per min. Iron (III) is sorbed to the Dowex 1 column with plutonium (IV) as well as uranium and polonium. Thoriu Dowee sorbes mi th column 0 x5 o t d . Trivalent actinides, americium and curium, on the other hand, pass through both columns. The column washee sar d with 50ml 9M HC1 effluene th , washingd tan combinee sar d and evaporate drynesso t d residue Th . thes ei n dissolve 1n Mi d HNO,-90% solutioCH HO n (50-100 ml). In order to obtain further purification of americium and curium, the solutio passes ni d throug secone th h d Dowe columx1 floa t wna rate minr pe .l oAmericiu2m f d curiu man colume e sorbeth mar n no d with other impurities, suc remainins ha g plutonium, poloniu d thoriumman colume Th .n is washed with HN0 M 1 60mCH.OH % f -l90 trivaleno e Th . t actinidee sar 0 *— J j then eluted with 0.5M HNO.-70% CH-OH (70 ml). When the plutonium determination is required, plutonium can be eluted from the first Dowex 1 column with 1.2M HC1 after washing with ~ 85 7.2M HNO, and analyzed by the procedure described by Talvitie . The elute which contains americium and curium is evaporated to dryness and the residue is dissolved with 0.8 ml concentrated HLSO,. The solution is diluted with distilled water and partially neutralized with finaa ammonid lan volum2 givo electrodepositioe t aH Th ep e. abouml 0 1 t n of americiu curiud man m from this solution ont stainlesoa s steel diss i c performe electrin a t a d c curren 1.2f hour1 to r Ausiny ,fo b disposablga e polyethylene electrolysi n viaa s la s cell similaA . r procedure th r efo 71 electrodepositio plutoniuf no alreads mha y been described presene th n I t work a-spectrometre ,th americiur yfo d an m curium was carried out using a silicon surface barrier detector having a 2 sensitive areresolutioe 300mf Th ao a-spectr e . mth f no 35-4s awa V 0ke 241 peam A k (5.4e th 9r MeV fo fule termn th i )l f widtso halt ha f maximum. The minimum detectable activity was 0.01 pCi for a 1000-min counting time. The key to precise determinations of americium in environmental samples is to obtain good decontamination from naturally-occurring 8 22 a-emitters, such as 21DP o (a-energy, 5.30 MeV) and Th (5.42 MeV) as 238 well as from the artificial fallout radionuclides such as Pu (5.49 MeV). 241 Their a-energies would interfere with the a-spectrometry of Am (5.49 MeV) 243 or of the yield-determinant Am (5.28 MeV). For curium determinations 80 O OC « , O Q£ separation from , Pu (5.76 MeV) is essential when Pu has been used as the yield monitors for plutonium, as its a-peak overlaps with that of 744 Cm (5.80 MeV). The decontamination of polonium with the present procedure verifies wa analyziny b d g samples which were know contaio nt n relatively 210 hig withou, hPo levelt f addinso y yielgan d monitor decontaminatioe Th . n factor for Po is estimated to be in the order of 10 . 210 However, since it was also observed that Pb is strongly sorbed on the anion exchange resin from the nitric acid-methanol medium, it 210 is possible that a small fraction of the Pb may be carried over to the 243 americium fraction and interfere with the a-spectrometry of Am, when 210 the content of Pb in samples in question is exceptionally high.
Load more

Recommended publications
  • Distribution Coefficients of Polonium Between 0.75 M HDEHP in Cyclo- Hexane and Aqueous Hydrochloric and Nitric Acids Guogang Jia* and Giancarlo Torri
    18 The Open Inorganic Chemistry Journal, 2008, 2, 18-21 Distribution Coefficients of Polonium Between 0.75 M HDEHP in Cyclo- hexane and Aqueous Hydrochloric and Nitric Acids Guogang Jia* and Giancarlo Torri Agency for Environmental Protection and for Technical Services, Via V. Brancati 48, 00144 Roma, Italy Abstract: The distribution coefficients (D) of polonium between 0.75 M di(2-ethyhexyl)phosphoric acid (HDEHP) in cy- clohexane and aqueous hydrochloric and nitric acids have been studied. Results indicate that: (1) D values are ranged from 32.7 to 0.00048 when the HCl acidities vary from 0.10 to 10.0 M, showing that polonium can well be extracted by 0.75 M HDEHP in cyclohexane if the aqueous HCl acidities are 0.050 M and it will not be extracted if 0.10 M HCl; (2) D values are ranged from 47.1 to 0.0117 when the HNO3 acidities vary from 0.10 to 10.0 M, showing that polonium can be extractable by 0.75 M HDEHP in cyclohexane and in a wide range acidity of 4 M HNO3. The different extraction behaviours of polonium in 0.75 M HDEHP in cyclohexane and different acidities of HCl and HNO3 were found. The find- ings will be very helpful to improve the methods involving polonium decontamination for determination and separation of americium, curium as well as other radioelements in environmental soil, water and biological samples. Keywords: Polonium, HDEHP, distribution coefficients. 1. INTRODUCTION on its oxidation state. Therefore, question is raised: which oxidation state is responsible for major polonium volatility, The element polonium (210Po) was discovered by Marie valences of +2, +4, and probably +6? Curie as the first element separated from pitchblende, and named after her home country, Poland [1, 2].
    [Show full text]
  • Factsheets & Faqs Polonium-210
    Factsheets & FAQs Polonium-210 Basic Facts Polonium-210 (Po-210) is a radioactive element that occurs naturally and is present in the environment at extremely low concentrations. Polonium was discovered by Marie Sklodowska-Curie and Pierre Curie in 1898 and was named after Marie's native land of Poland (Latin: Polonia). This element was the first one discovered by them while they were investigating the cause of pitchblende radioactivity. It is a fairly volatile (50% is vaporized in air in 45 hours at 55°C) silvery-grey soft metal. Po-210 has a half-life of 138 days. This is the time it takes for the activity to decrease by half due to a process of radioactive decay. Po-210 decays to stable lead-206 by emitting alpha particles, accompanied by very low intensity gamma rays. The majority of the time Po-210 decays by emission of alpha particles only, not by emission of an alpha particle and a gamma ray. Only about one in a 100,000 decays results in the emission of a gamma ray. Alpha spectroscopy is the best method of measuring this isotope. Origin Being produced during the decay of naturally occurring uranium-238, polonium-210 is widely distributed in small amounts in the earth's crust. Although it can be produced by the chemical processing of uranium ores or minerals, uranium ores contain less than 0.1 mg Po-210 per ton. Because Po-210 is produced from the decay of radon-222 gas, it can be found in the atmosphere from which it is deposited on the earth's surface.
    [Show full text]
  • Periodic Table of the Elements Notes
    Periodic Table of the Elements Notes Arrangement of the known elements based on atomic number and chemical and physical properties. Divided into three basic categories: Metals (left side of the table) Nonmetals (right side of the table) Metalloids (touching the zig zag line) Basic Organization by: Atomic structure Atomic number Chemical and Physical Properties Uses of the Periodic Table Useful in predicting: chemical behavior of the elements trends properties of the elements Atomic Structure Review: Atoms are made of protons, electrons, and neutrons. Elements are atoms of only one type. Elements are identified by the atomic number (# of protons in nucleus). Energy Levels Review: Electrons are arranged in a region around the nucleus called an electron cloud. Energy levels are located within the cloud. At least 1 energy level and as many as 7 energy levels exist in atoms Energy Levels & Valence Electrons Energy levels hold a specific amount of electrons: 1st level = up to 2 2nd level = up to 8 3rd level = up to 8 (first 18 elements only) The electrons in the outermost level are called valence electrons. Determine reactivity - how elements will react with others to form compounds Outermost level does not usually fill completely with electrons Using the Table to Identify Valence Electrons Elements are grouped into vertical columns because they have similar properties. These are called groups or families. Groups are numbered 1-18. Group numbers can help you determine the number of valence electrons: Group 1 has 1 valence electron. Group 2 has 2 valence electrons. Groups 3–12 are transition metals and have 1 or 2 valence electrons.
    [Show full text]
  • Polonium Human-Injection Experiments Injection and Lived Another 8 Years Be- Fore Dying, in 1953, of Heart Failure
    The Human Plutonium Injection Experiments any effect on the normal course of his life.” HP-12 was 53 at the time of the Polonium Human-Injection Experiments injection and lived another 8 years be- fore dying, in 1953, of heart failure. In 1944, in response to concerns for the risk associated with occupational Late radiation effects, such as cancer, exposures to polonium, the Army Medical Corps authorized Rochester to un- were not expected to develop for ten to dertake a study of the biological behavior of that element. The program was fifteen years, if at all. For example, the started in August 1944 with animals, and by November, studies with humans induction period in humans for radium- had begun. Eventually, tracer amounts of radioactive polonium-210 were in- induced cancer, especially malignancy jected into four hospitalized humans and ingested by a fifth. of the bones, was about 10 to 30 years after exposure. Despite Langham’s Polonium, the first element isolated by Marie and Pierre Curie from pitch- statement, we cannot, of course, dis- blende in 1898, is an alpha emitter. When alpha particles from polonium- count the fact that HP-12 might have 210 collide with beryllium atoms, neutrons are ejected, and polonium-berylli- lived 20 or more years; although in um combinations had already served physicists as a convenient source of 1945, fifty years of age was considered neutrons. During the Manhattan Project, it was decided to use that neutron to be fairly advanced. On the other source as an initiator of the chain reaction in the atomic bombs, thus making hand, the GIs at Los Alamos who were polonium (and beryllium) an occupational health hazard for the people who heavily exposed to plutonium in 1945 needed to develop and build the initiators.
    [Show full text]
  • Genius of the Periodic Table
    GENIUS OF THE PERIODIC TABLE "Isn't it the work of a genius'. " exclaimed Academician V.I. Spitsyn, USSR, a member of the Scientific Advisory Committee when talking to an Agency audience in January. His listeners shared his enthusiasm. Academician Spitsyn was referring to the to the first formulation a hundred years ago by Professor Dmitry I. Mendeleyev of the Periodic Law of Elements. In conditions of enormous difficulty, considering the lack of data on atomic weights of elements, Mendeleyev created in less than two years work at St. Petersburg University, a system of chemical elements that is, in general, still being used. His law became a powerful instrument for further development of chemistry and physics. He was able immediately to correct the atomic weight numbers of some elements, including uranium, whose atomic weight he found to be double that given at the time. Two years later Mendeleyev went so far as to give a detailed description of physical or chemical properties of some elements which were as yet undiscovered. Time gave striking proof of his predictions and his periodic law. Mendeleyev published his conclusions in the first place by sending, early in March 186 9, a leaflet to many Russian and foreign scientists. It gave his system of elements based on their atomic weights and chemical resemblance. On the 18th March that year his paper on the subject was read at the meeting of the Russian Chemical Society, and two months later the Society's Journal published his article entitled "The correlation between properties of elements and their atomic weight".
    [Show full text]
  • The Environmental Behaviour of Polonium
    technical reportS series no. 484 Technical Reports SeriEs No. 484 The Environmental Behaviour of Polonium F. Carvalho, S. Fernandes, S. Fesenko, E. Holm, B. Howard, The Environmental Behaviour of Polonium P. Martin, M. Phaneuf, D. Porcelli, G. Pröhl, J. Twining @ THE ENVIRONMENTAL BEHAVIOUR OF POLONIUM The following States are Members of the International Atomic Energy Agency: AFGHANISTAN GEORGIA OMAN ALBANIA GERMANY PAKISTAN ALGERIA GHANA PALAU ANGOLA GREECE PANAMA ANTIGUA AND BARBUDA GUATEMALA PAPUA NEW GUINEA ARGENTINA GUYANA PARAGUAY ARMENIA HAITI PERU AUSTRALIA HOLY SEE PHILIPPINES AUSTRIA HONDURAS POLAND AZERBAIJAN HUNGARY PORTUGAL BAHAMAS ICELAND QATAR BAHRAIN INDIA REPUBLIC OF MOLDOVA BANGLADESH INDONESIA ROMANIA BARBADOS IRAN, ISLAMIC REPUBLIC OF RUSSIAN FEDERATION BELARUS IRAQ RWANDA BELGIUM IRELAND SAN MARINO BELIZE ISRAEL SAUDI ARABIA BENIN ITALY SENEGAL BOLIVIA, PLURINATIONAL JAMAICA SERBIA STATE OF JAPAN SEYCHELLES BOSNIA AND HERZEGOVINA JORDAN SIERRA LEONE BOTSWANA KAZAKHSTAN SINGAPORE BRAZIL KENYA SLOVAKIA BRUNEI DARUSSALAM KOREA, REPUBLIC OF SLOVENIA BULGARIA KUWAIT SOUTH AFRICA BURKINA FASO KYRGYZSTAN SPAIN BURUNDI LAO PEOPLE’S DEMOCRATIC SRI LANKA CAMBODIA REPUBLIC SUDAN CAMEROON LATVIA SWAZILAND CANADA LEBANON SWEDEN CENTRAL AFRICAN LESOTHO SWITZERLAND REPUBLIC LIBERIA SYRIAN ARAB REPUBLIC CHAD LIBYA TAJIKISTAN CHILE LIECHTENSTEIN THAILAND CHINA LITHUANIA THE FORMER YUGOSLAV COLOMBIA LUXEMBOURG REPUBLIC OF MACEDONIA CONGO MADAGASCAR TOGO COSTA RICA MALAWI TRINIDAD AND TOBAGO CÔTE D’IVOIRE MALAYSIA TUNISIA CROATIA MALI
    [Show full text]
  • Periodic Table Facts
    Periodic Table Facts Compact Periodic Table Table Layout The periodic table is normally presented in a compressed form with Transition Metals the Lanthanides (elements 57-71) and Actinides (elements 89-103) in separate rows below the rest of the table. This is A. Earth Metals Metals Earth A. done to make the table more Lanthanides compact. In the extended table, Actinides shown below, these elements are inserted in their proper position between the Alkaline Earth Metals and the Transition Metals. Extended Periodic Table Transition Metals Lanthanides A. Earth Metals Metals Earth A. Actinides increasing mass How Small Are Atoms? Atoms are very, very small. To similar understand how small atoms are, start properties by looking at a meter stick. A meter can be divided into 1000 smaller lengths called millimeters. Now think of that millimeter and divide it into 1000 smaller lengths called micrometers. Now think of that micrometer and Periodic Trends divide it into 1000 even smaller lengths Dmitri Mendeleëv organized elements called nanometers. One nanometer is in the Periodic Table according to large enough for about 5 carbon their mass and reactive properties. He atoms. recognized that some elements had It would take 7,000,000 (7 million) similar properties, so he placed them carbon atoms stacked on top of each in the same column. He placed the other to be the thickness of a dime. elements from left to right in order of increasing mass. Mendeleëv left It would take 120,000,000 (120 million) spaces in his original table for carbon atoms to cross the face of elements that hadn’t yet been a dime.
    [Show full text]
  • Polonium-210
    Health Physics Society Fact Sheet Adopted: May 2010 Revised: June 2020 Health Physics Society Specialists in Radiation Safety Polonium-210 General In 1898, Marie and Pierre Curie discovered their first radioactive* element. It was later named polonium in honor of Marie Sklodowska Curie’s native Poland. Polonium, a naturally occurring element that can be found throughout our environment, results from the radioactive decay of radon-222 gas—a part of the uranium-238 decay chain. There are over 30 known isotopes of polonium, and all are radioactive, but the one occurring most in nature—and the one most widely used—is polonium-210 (210Po). With a half-life of 138 days, it decays to stable lead-206 by the emission of an alpha particle (an alpha particle has two protons and two neutrons). Radioactive materials are quantified by activity, or the number of disintegrations that occur over a period of time. A terabecquerel (TBq), for instance, is equal to 1 x 1012 disintegrations per second. Polonium-210 has a very high specific activity—activity per unit mass—of about 166 TBq per gram (4,490 curies, Ci, per gram). In other words, it doesn’t take a large physical amount to be very radioactive. Because of the high specific activity and the large associated thermal cross section, according to a human health fact sheet for 210Po produced by Argonne National Laboratory, a capsule containing about 0.5 grams (83 TBq) of 210Po can reach temperatures exceeding 500o C (ANL 2005). When it is purified, polonium melts at a low temperature and can be quite volatile.
    [Show full text]
  • The Elements.Pdf
    A Periodic Table of the Elements at Los Alamos National Laboratory Los Alamos National Laboratory's Chemistry Division Presents Periodic Table of the Elements A Resource for Elementary, Middle School, and High School Students Click an element for more information: Group** Period 1 18 IA VIIIA 1A 8A 1 2 13 14 15 16 17 2 1 H IIA IIIA IVA VA VIAVIIA He 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 Na Mg IIIB IVB VB VIB VIIB ------- VIII IB IIB Al Si P S Cl Ar 22.99 24.31 3B 4B 5B 6B 7B ------- 1B 2B 26.98 28.09 30.97 32.07 35.45 39.95 ------- 8 ------- 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.47 58.69 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr NbMo Tc Ru Rh PdAgCd In Sn Sb Te I Xe 85.47 87.62 88.91 91.22 92.91 95.94 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La* Hf Ta W Re Os Ir Pt AuHg Tl Pb Bi Po At Rn 132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222) 87 88 89 104 105 106 107 108 109 110 111 112 114 116 118 7 Fr Ra Ac~RfDb Sg Bh Hs Mt --- --- --- --- --- --- (223) (226) (227) (257) (260) (263) (262) (265) (266) () () () () () () http://pearl1.lanl.gov/periodic/ (1 of 3) [5/17/2001 4:06:20 PM] A Periodic Table of the Elements at Los Alamos National Laboratory 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanide Series* Ce Pr NdPmSm Eu Gd TbDyHo Er TmYbLu 140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Actinide Series~ Th Pa U Np Pu AmCmBk Cf Es FmMdNo Lr 232.0 (231) (238) (237) (242) (243) (247) (247) (249) (254) (253) (256) (254) (257) ** Groups are noted by 3 notation conventions.
    [Show full text]
  • Frequently Asked Questions About Polonium 210
    Frequently Asked Questions about Polonium 210 What is Polonium 210 (Po-210)? Po-210 is a radioactive material that occurs in nature at very low levels. Po-210 results from the natural radioactive decay of uranium, which is commonly found in Sierra Nevada granites. Po-210 emits alpha particles, which makes it decay to form a stable isotope of lead. The alpha particles carry high amounts of energy which can damage or destroy genetic material in cells inside the body. Po- 210 is considered to be one of the most hazardous radioactive materials known, but it must be breathed in or eaten to exert its toxic effects. Your skin or a piece of paper is enough to stop the radiation emitted by Po-210. What are common uses of Polonium 210? Po-210 is used in some devices to eliminate static electricity in processes such as rolling paper, manufacturing sheet plastics, and spinning synthetic fibers. How is Po-210 measured? The concentration of Po-210 in water is measured in pCi/L. A picocurie is a unit of measure for radioactivity in air and water. This represents the amount of radiation that is emitted from a radioactive substance such as Po-210. A picocurie is one million millionth, or a trillionth, of a curie. Polonium in Water What is considered a safe concentration of Po-210 in water? It is very unusual for ground water to have concentrations of Po-210 greater than 1 picocurie per liter. The US Environmental Protection Agency has not established drinking water standards specifically for Po-210.
    [Show full text]
  • What Is the Relationship Between Radioactivity and Radon?
    General Academic Unit Radon Alert INVESTIGATION 4 WHAT IS THE RELATIONSHIP BETWEEN RADIOACTIVITY AND RADON? INTRODUCTION Radon is a naturally-occurring radioactive gas. It is formed by the radioactive breakdow of radium, and is found in soils just about everywhere. You cannot see it, taste it, or smell it. is continuously formed in rocks and soils and escapes into the atmosphere. In some cases, makes its way into homes, builds up to high concentrations in indoor air, and can become a healt hazard. Although there are several Radioactivity - the spontaneous emission of energy different isotopes of radon, the one from the nucleus of certain (radioactive) atoms, resulting that is of greatest concern as a potential in a change from one element to another. The energy human health threat is called radon- can be in the form of alpha or beta particles and gamma 222. Radon-222 is formed naturally rays. during a chain of radioactive Shells or Energy Levels disintegration reactions (decay series). Which Electrons Occupy The decay series begins when Around the Nucleus uranium-238 decays. Uranium is widely distributed in rocks and soils Nucleus Protons throughout the earth’s crust. It has a half-life of 4.5 billion years, which Neutrons means a very slow breakdown. The decay series is shown in Figure 1 and in Table 1. There are eight different elements and 15 different isotopes in Electron the series, beginning with uranium- A model of an atom. 238 and ending with lead-206. New elements formed by radioactive disintegration are called decay products. Thus, radium-226 is one of the decay products o uranium-238.
    [Show full text]
  • The Human Plutonium Injection Experiments William Moss and Roger Eckhardt
    The Human Plutonium Injection Experiments William Moss and Roger Eckhardt he human plutonium injection experiments carried out during and after the Manhattan Project have received tremendous noto- Triety in the past year or so owing to the Pulitzer-prize winning journalism of Eileen Welsome in the Albuquerque Tribune in 1993. The purpose of those experiments was to develop a diagnostic tool that could determine the uptake of plutonium in the body from the amount excreted in the urine and feces. This tool was essential for the protec- tion of workers who would produce and fashion plutonium metal for use in the early atomic bombs. The idea was to remove a worker from the job if and when it was determined that the he had received an inter- nal dose that was close to or over the limit considered safe. Although some of the results of the studies were declassified and re- ported in the scientific literature in the early fifties (and further reports appeared in the seventies), the names of the subjects were not dis- closed. Investigative reporting by Welsome uncovered the identities of five of the eighteen subjects and gave details about the circumstances and lives of three of them. The secret nature of the studies and the fact that the subjects may not have been informed about what was being done to them has generated outrage and distrust in the general pubic regarding the practices of the national laboratories. Why were such experiments done? Who allowed them to happen? The Secre- tary of Energy, Hazel O’Leary, equally disturbed, pledged an era of openness in the Department, promising to make available to the public all information that could be located that was pertinent to those and Louis Hempelmann 177 The Human Plutonium Injection Experiments similar radiation experi- in the gaseous-diffusion method, ments with humans.
    [Show full text]