DOCSLIB.ORG

Periodicity in Domestic Radon Time Series

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Periodicity in Domestic Radon Time Series Periodicity in Domestic Radon Time Series - Evidence for Earth Tides C J Groves-Kirkby1, A R Denman1, R G M Crockett2, P S Phillips3 1Medical Physics Department, Northampton General Hospital, Northampton NN5 1 BD, UK E-Mail: [email protected] 2School of Technology and Design, University College Northampton, St. George's Avenue, Northampton NN2 6JD, U.K. 3SITA Centre, School of Environmental Science, University College Northampton, Northampton NN2 7AL, UK Abstract. Although long-term average radon levels in domestic properties determine the overall lung cancer risk to occupants, for a variety of reasons it is generally preferable to make radon determinations using short-term methods. However, while accurate radon determination is technically possible on a time-scale of hours, typical diurnal radon variation may span one or two orders of magnitude, hindering characterization of long-term concentration from short-term measurement. Averaging over more than one day eliminates diurnal fluctuations, but is susceptible to day-to-day variations, due to factors such as lifestyle, weather patterns etc. To explore the use of short-term exposures as measures of long-term trends, the time-dependence of radon levels in three homes was monitored over periods ranging from three to seven months, using Durridge RAD-7 monitors, providing continuous data sets for radon level at hourly intervals throughout the measurement periods. Two of the sites are situated 2 km apart on similar, but not identical, geology (Northampton Sand) and both possess cellars, providing relatively undisturbed measuring environments. Despite these similarities, radon levels at the two sites differ by an order of magnitude. Regression and cross-correlation of radon levels with environmental parameters showed weak contributions to variability from mean temperature and rainfall. Autocorrelation and Fourier transformation of the radon time-sequences identified a number of characteristically periodic features. Daily, weekly and monthly contributions, some common to more than one property, others location-specific, were identified, with differing strengths reflecting local occupation patterns. Two properties exhibited components having periodicity of 23.9 hours (the luni-solar diurnal period) and 24.0 hours (the solar day), while one gave indication of a 168 hour (one week) cycle. In addition, evidence appeared of periodicity around 661 hours (27 days, 13 hours), the Lunar Month, together with positive correlation with tidal strength, suggesting that 'Earth Tides' contribute to the periodic liberation of radon, possibly via geophysically driven variations in ground-water level. 1. Introduction Radon is a naturally occurring radioactive noble gas, having variable distribution in the geological environment as a decay product of natural uranium found, in differing degrees, in a wide range of rocks and soils, and in building materials incorporating or manufactured from these. There are three naturally occurring isotopes, 222Rn, a direct product of 226Ra in the 238U decay-series with a half-life of 3.8 days, 220Rn, a decay product of 232Th, with a half-life of 55.6 s, and 219Rn, a decay product of 235U, with a half-life of 3.6 s. Radon has high mobility, enabling it to move out of underlying rocks into caves, mines and the built environment. Of the three isotopes, 222Rn is the most significant, its relatively long half-life enabling it to migrate quite significant distances within the geological environment before decaying. Although radon dissipates rapidly once in outdoor air, it concentrates in the built environment. For UK dwellings, the mean radon level is around 20 Bq·m-3, compared to 4 Bq·m-3 in outside air [1], but levels up to 10,000 Bq·m-3 have been found in domestic housing. Ionising radiation is well known to have adverse health effects, and inhalation of radon and its progeny 218Po and 214Po adsorbed onto atmospheric particulates is currently believed [2] to provide the majority of dose to the respiratory system. This damages the sensitive inner lining of the lung, increasing the risk of cancer, and it is estimated [2] that the annual mortality from exposure to radon in buildings represents 6 % of all deaths from lung cancer in England. The total annual mortality from this type of cancer is between 30,000 and 35,000, suggesting that between 1,800 and 2,100 deaths annually are caused by exposure to radon and its progeny. There is therefore a significant motivation for the development of reliable techniques for characterising baseline domestic radon levels. Determination of domestic radon concentration based on short-term measurements is confounded by the presence of numerous periodicities affecting mechanisms driving the liberation of radon gas from the soil. Thus, a measurement extending over a few hours may be influenced by the time of day at 1 which the data is taken. Similarly, a measurement lasting a day or a few days may depend on which days in the week are involved. On the longer time-scale, this problem has been recognized by the application of seasonal correction factors [3] to one-month and three-month measurements. Although techniques exist for accurate determination of radon levels over intervals of the order of hours or less, typical diurnal variation in radon level may be two to three orders of magnitude, militating against reliable short-period characterization of domestic premises. By averaging over periods of more than one day, diurnal fluctuations can be effectively eliminated, providing a more meaningful assessment of true radon concentration, but simultaneously introducing potential confusion from day-to-day variations, due to factors such as lifestyle, weather patterns etc. Our recent and ongoing studies on domestic radon levels have addressed radon baseline concentration characterization through relatively short exposures [4]. To explore the viability of utilising short-term, e.g. 3-day or 7-day, exposures as measures of long-term trends, the time-dependence of radon levels in three homes was monitored over extended periods. This approach provided continuous data sets for radon level and ambient temperature at hourly intervals. We present here some observations and conclusions arising from analysis of the periodicities occurring in these data sets. 2. Methodology 2.1. Instrumentation For quasi-continuous time-series monitoring of domestic radon concentrations, two sets of Durridge RAD-7 radon detection equipment 1 were available. The RAD-7 is a portable instrument, operating by electrostatic collection of α-emitters with associated spectral analysis, capable of measuring the ambient radioactivity concentration in a matter of minutes and operating in unattended continuous mode for several weeks. Air from the sampling point is drawn by a pump through a length of flexible tube, passing through a drying column and two filters before entering the 0.7 litre sample cell. The immediate product of any radon decay occurring in the cell is a positively charged 218Po ion, which moves under the influence of the internally applied electric field and is deposited onto the solid-state detector. Subsequent decays produce further α-particles, which have a 50 % probability of entering the detector and which are counted in two main energy channels, Channel A for 218Po and Channel C for the subsequent progeny 214Po. The results, up to 999 in any continuous automatic cycle, are stored as a data table and can be printed as a time-series at the end of each measurement cycle, when the mean radon concentration during the cycle is calculated. The RAD-7 is calibrated by the manufacturer against a master instrument, which, in turn, is calibrated against a standard maintained by the National Radiological Protection Board (NRPB). The overall calibration accuracy is estimated to be about ±5 %. In most circumstances, the precision of individual RAD-7 measurements of radon concentration is limited by counting statistics. Some examples of normal mode counting precision are given in Table I. Table I. RAD-7 Normal mode counting errors – counting time = 1 hour Radon Concentration[Bq·m-3] 20 400 1000 Number of counts (N) 15 300 750 Error: ± 2σ = ±2√N ±52 % ±12 % ±7 % 2.2. Instrumentation Placement Sets of RAD-7 equipment were initially installed in infrequently-used cellars in two domestic properties, A and B, situated around 2 km apart on similar geology, Northamptonshire Sand, in the town of Northampton, England. Despite these similarities, the two sites exhibit radon levels differing by an order of magnitude or more, reflecting differing values of radon potential [5] at the two sites. 1 Durridge RAD-7 Professional Radon Detector. Durridge Company, 7 Railroad Avenue, Suite D, Bedford, MA 01730, USA. 2 Following a period of approximately six months when both Property A and Property B were monitored simultaneously, Property B and Property C, also on Northamptonshire Sand but without a cellar, were compared for a further three months. Both sets of equipment were then operated in close proximity in an infrequently-used ground-floor room in Property C for a period of around six weeks, following which they were operated for three months (July – September 2003) in a relatively undisturbed room in Property D, a workplace location known [6] to have relatively high radon levels. The relevant operation dates, measurement periods and locations are summarized in Table II. Table II. Operating Locations and Schedule for RAD-7 Equipment Sets Equipment Identifier Property Start Date Finish Date Duration [d] 'a' TS1a B 27th June 2002 19th December 2002 175 B 19th December 2002 9th January 2003 21 TS2a B 9th January 2003 27th March 2003 77 TS3a C 4th April 2003 17th May 2003 43 TS4a D 6th June 2003 10th September 2003 96 'b' TS1b A 27th June 2002 19th December 2002 175 TS2b C 9th January 2003 27th March 2003 77 TS3b C 4th April 2003 17th May 2003 43 TS4b D 6th June 2003 10th September 2003 96 2.3.
Load more

Recommended publications
  • What Is Radon?
    Biology Unit Radon Alert INVESTIGATION 3 WHAT IS RADON? INTRODUCTION Radon is a naturally occurring radioactive gas. It is formed by the radioactive breakdown of radium, and is found in soils just about everywhere. You cannot see it, taste it, or smell it. It is continuously formed in rocks and soils and escapes into the atmosphere. In some cases, it makes its way into homes, builds up to high concentrations in indoor air, and can become a health hazard. Although there are several different isotopes of radon, the one that is of greatest concern as a potential Radioactivity - the spontaneous human health threat is called radon-222. Radon-222 is emission of energy by certain (radio- formed naturally during a chain of radioactive disintegra- active) atoms, resulting in a change tion reactions (decay series). The decay series begins from one element to another or one when uranium-238 decays. Uranium is widely distrib- isotope to another. The energy can uted in rocks and soils throughout the earth’s crust. It has be in the form of alpha or beta par- a half-life of 4.5 billion years, which means a very slow ticles and gamma rays. breakdown. The decay series is shown schematically in Figure 1. There are eight different elements and 15 different isotopes in the series, beginning with uranium- 238 and ending with lead-206. New elements formed by radioactive disintegration reactions are called decay products. Thus, radium-226 is one of the decay products of uranium-238. Polonium-218 and lead-214 are decay products of radon-222.
    [Show full text]
  • Of the Periodic Table
    of the Periodic Table teacher notes Give your students a visual introduction to the families of the periodic table! This product includes eight mini- posters, one for each of the element families on the main group of the periodic table: Alkali Metals, Alkaline Earth Metals, Boron/Aluminum Group (Icosagens), Carbon Group (Crystallogens), Nitrogen Group (Pnictogens), Oxygen Group (Chalcogens), Halogens, and Noble Gases. The mini-posters give overview information about the family as well as a visual of where on the periodic table the family is located and a diagram of an atom of that family highlighting the number of valence electrons. Also included is the student packet, which is broken into the eight families and asks for specific information that students will find on the mini-posters. The students are also directed to color each family with a specific color on the blank graphic organizer at the end of their packet and they go to the fantastic interactive table at www.periodictable.com to learn even more about the elements in each family. Furthermore, there is a section for students to conduct their own research on the element of hydrogen, which does not belong to a family. When I use this activity, I print two of each mini-poster in color (pages 8 through 15 of this file), laminate them, and lay them on a big table. I have students work in partners to read about each family, one at a time, and complete that section of the student packet (pages 16 through 21 of this file). When they finish, they bring the mini-poster back to the table for another group to use.
    [Show full text]
  • Keeping Your Home Safe from RADON
    Keeping Your Home Safe From RADON 800-662-9278 | Michigan.gov/radon 08/2019 What is Radon? Radon is a colorless and odorless gas that comes from the soil. The gas can accumulate in our home and in the air we breathe. Radon gas decays into fine particles that are radioactive. When inhaled, these fine particles can damage the lung. Exposure to radon over a long period of time can lead to lung cancer. It is estimated that 21,000 people die each year in the United States from lung cancer due to radon exposure. A radon test is the only way to know how much radon is in your home. Radon can be reduced with a mitigation system. The Michigan Department of Environment, Great Lakes, and Energy (EGLE) has created this guide to explain: • How radon accumulates in homes • The health risks of radon exposure • How to test your home for radon • What to do if your home has high radon • Radon policies C Keeping Your Home Safe From Radon Table of Contents Where Does Radon Come From? ............................................. 1 Radon in Michigan ....................................................................... 1 Percentage of Elevated Radon Test Results by County ......... 2 Is There a Safe Level of Radon? ............................................... 3 Radon Health Risks ..................................................................... 4 How Radon Enters the Home ..................................................... 6 Radon Pathways ........................................................................... 7 Radon Testing ............................................................................
    [Show full text]
  • Radionuclides (Including Radon, Radium and Uranium)
    Radionuclides (including Radon, Radium and Uranium) Hazard Summary Uranium, radium, and radon are naturally occurring radionuclides found in the environment. No information is available on the acute (short-term) noncancer effects of the radionuclides in humans. Animal studies have reported inflammatory reactions in the nasal passages and kidney damage from acute inhalation exposure to uranium. Chronic (long-term) inhalation exposure to uranium and radon in humans has been linked to respiratory effects, such as chronic lung disease, while radium exposure has resulted in acute leukopenia, anemia, necrosis of the jaw, and other effects. Cancer is the major effect of concern from the radionuclides. Radium, via oral exposure, is known to cause bone, head, and nasal passage tumors in humans, and radon, via inhalation exposure, causes lung cancer in humans. Uranium may cause lung cancer and tumors of the lymphatic and hematopoietic tissues. EPA has not classified uranium, radon or radium for carcinogenicity. Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS) (5), which contains information on oral chronic toxicity and the RfD for uranium, and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profiles for Uranium, Radium, and Radon. (1) Uses Uranium is used in nuclear power plants and nuclear weapons. Very small amounts are used in photography for toning, in the leather and wood industries for stains and dyes, and in the silk and wood industries. (2) Radium is used as a radiation source for treating neoplastic diseases, as a radon source, in radiography of metals, and as a neutron source for research.
    [Show full text]
  • Recalling Radon's Recognition
    in your element Recalling radon’s recognition Brett F. Thornton and Shawn C. Burdette look back at the discovery — and the many different names — of element 86. n 1899, Pierre and Marie Curie noted an Thoron, unlike radon, requires no such “induced radioactivity” — left behind by clarification, and 220Rn is routinely called Iradium, distinct from its own radioactivity. thoron today. Thoron is far easier to say Ernest Rutherford and Robert B. Owens also than ‘radon-two-twenty’, perhaps explaining reported that year on a radioactive substance why the annual count of scientific papers 220 ( Rn, t1/2 = 55.6 s) emitted by thorium, which mentioning thoron has increased over twenty- they called emanation. In 1900, Friedrich fold since thoron was ‘disallowed’ in 1957. Dorn realized that the Curies had observed a Distinguishing between 222Rn (the 222 220 unique substance ( Rn, t1/2 = 3.8 d), similar isotope called ‘radon’) and Rn (thoron) is to emanation. In 1904, André-Louis Debierne not of idle linguistic and historic interest. 222 found a third radioactive particle; this one © SUPERSTOCK/ALAMY Rn can persist indoors, whereas the short- 219 produced from actinium ( Rn, t1/2 = 4 s). lived thoron cannot. Not all home radon These were at first regarded as elements and actinon (An) for the three isotopes; detectors (pictured) are sensitive to thoron, and became colloquially known as thorium names suggested by Elliott Q. Adams. and thoron-sensitive detectors must be emanation, radium emanation and actinium An official statement on a name for all placed with care because thoron does not emanation, but today we recognize them three isotopes — that is, a name for the travel far from its source.
    [Show full text]
  • The Noble Gases
    INTERCHAPTER K The Noble Gases When an electric discharge is passed through a noble gas, light is emitted as electronically excited noble-gas atoms decay to lower energy levels. The tubes contain helium, neon, argon, krypton, and xenon. University Science Books, ©2011. All rights reserved. www.uscibooks.com Title General Chemistry - 4th ed Author McQuarrie/Gallogy Artist George Kelvin Figure # fig. K2 (965) Date 09/02/09 Check if revision Approved K. THE NOBLE GASES K1 2 0 Nitrogen and He Air P Mg(ClO ) NaOH 4 4 2 noble gases 4.002602 1s2 O removal H O removal CO removal 10 0 2 2 2 Ne Figure K.1 A schematic illustration of the removal of O2(g), H2O(g), and CO2(g) from air. First the oxygen is removed by allowing the air to pass over phosphorus, P (s) + 5 O (g) → P O (s). 20.1797 4 2 4 10 2s22p6 The residual air is passed through anhydrous magnesium perchlorate to remove the water vapor, Mg(ClO ) (s) + 6 H O(g) → Mg(ClO ) ∙6 H O(s), and then through sodium hydroxide to remove 18 0 4 2 2 4 2 2 the carbon dioxide, NaOH(s) + CO2(g) → NaHCO3(s). The gas that remains is primarily nitrogen Ar with about 1% noble gases. 39.948 3s23p6 36 0 The Group 18 elements—helium, K-1. The Noble Gases Were Kr neon, argon, krypton, xenon, and Not Discovered until 1893 83.798 radon—are called the noble gases 2 6 4s 4p and are noteworthy for their rela- In 1893, the English physicist Lord Rayleigh noticed 54 0 tive lack of chemical reactivity.
    [Show full text]
  • Radon in the Helium-Bearing Natural Gas of the Texas Panhandle
    ej f Radon in the Helium-Bearing Natural Gas of the Texas Panhandle Trace Elements Memorandum Report 239 IN REPLY REFER TO: UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY WASHINGTON 25, D. C. AEC-4-98/1 Dr0 Phillip L 0 Merritt, Assistant Manager Raw Materials Operations U0 So Atomic Energy Commission Po 00 Box 30? Ansonia Station New York 23, New York Dear Phils Transmitted herewith for your information and distribution are 8 copies of Trace Elements Memorandum Report 239 9 "Radon in the helium=>bearing natural gas of the Texas Panhandle," by H0 Faul, Go Eo Mangerj and A0 Y0 Sakakura 0 Our measurements of the radon content of natural gas samples from 84 producing wells in the Texas Panhandle gas field show signifi- cant differences5 furthermore 9 the wells with the highest radon content occur in clusters suggesting a marked variation in the distribution of the parent elements of radon, namely radium and uranium., within or near the gas reservoir., Analysis of the radon data in relation to possible source distribution suggests that rocks containing average concentrations of uranium could not supply the amount of radon observed in most of the gas wellso Further research on the emanating power of granite and dolo­ mite is required to determine whether the radon observed is attributable to radioactive elements in the reservoir rock or to radioactive elements outside the reservoir volume proper0 The Oak Ridge National Laboratory k©s already initiated preliminary studies of the emanating power of the selected dolomite samples 0 Additional radon measurements, are needed to establish the limits of the abnormal radon concentration and further delineate the possible distribution of the parent !.element 0 Sincerely yours., '^SvwA^ W0 H Bradley I Chief Geologist fITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY RADON IN THE HELIUM-BEARING NATURAL GAS OF THE TEXAS PANHANDLE H.
    [Show full text]
  • Radon Signals in XENON1T
    P.A. (Sander) Breur Nikhef, Netherlands Radon signals in XENON1T XeSAT 2017 XENON1T Our goal: Our setup: 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 2 XENON1T is taking science data 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 3 XENON1T is taking science data 10/2016 03/2017 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 4 Radon expectations 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 5 MC background expectation Physics reach of the XENON1T dark matter experiment, http://arxiv.org/abs/1512.07501 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 6 Reducing radon • Surface cleaning/coating • Emanation measurements • Expectation: 10 μBq/kg for XENON1T More info: “Radon depletion in xenon boil-off gas” (arXiv:1611.03737) and “Online 222Rn removal by cryogenic distillation in the Radon emanation paper in preparation XENON100 experiment” (arXiv: 1702.06942) 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 7 The 'radon' spectrum 5.6 MeV Low energy Low 7.8 MeV 5.4 MeV 6.1 MeV Isotope Energy [MeV] Half-life 210Po 5.4 138 d 222Rn 5.6 3.8 d 218Po 6.1 3.1 m Physics reach of the XENON1T dark matter experiment, http://arxiv.org/abs/1512.07501 214Po 7.8 162.3 us 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 8 Radon signals in XENON1T 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 9 The four alpha lines of Radon 05/04/2017 Xesat 2017 - P.A. Breur (Nikhef) - XENON 10 The four alpha lines of Radon • 214Po has a half life of 164μs • 214Bi and 214Po are always recorded in the same event window S1alpha S2beta S1beta S2alpha 05/04/2017 Xesat 2017 - P.A.
    [Show full text]
  • Radon Measurement Service Provider
    ~ 1 ~ HOW TO PERFORM RADON INSPECTIONS: RADON MEASUREMENT SERVICE PROVIDER Radon measurement is a specialized type of service that goes beyond the scope of a general home inspection. The purpose of this publication is to provide accurate and useful information for performing radon consultations and tests for residential buildings. The material in this book covers the science, properties and causes of radon, as well as the potential hazards it presents to occupants’ health. Inspectors will learn how to test for radon both before and after mitigation and to make appropriate recommendations. Also presented here are radon testing protocols based on the requirements for the U.S. EPA's former Radon Proficiency Program. This book is designed to augment the student’s knowledge in preparation for InterNACHI’s online Radon Measurement Service Provider Course and Final Exam (www.nachi.org), and includes practice quizzes for select sections. This publication, and the online course on which this book is based, prepare participants for the NEHA-NRPP Measurement Exam, which has been approved by the International Association of Certified Home Inspectors (InterNACHI). Contact your state to determine the requirements for becoming certified as either a radon mitigator or a radon measurement service provider, which may include taking the National Radon Proficiency Measurement Exam (NEHA-NRPP). Taking the online course is also a requirement for Radon Certification by the International Association of Certified Indoor Air Consultants (IAC2.org). This manual
    [Show full text]
  • Reducing the Risks from Radon: Information and Interventions a Guide for Health Care Providers
    Reducing the Risks From Radon: Information and Interventions A Guide for Health Care Providers Indoor Air Quality (IAQ) What Is Radon? Radon-222 (radon) is a radioactive gas with a half-life of 3.8 days that is released during the decay of uranium-238 and subsequently radium-226, which are naturally occurring elements found in varying amounts in rock, soil and groundwater. Odorless, invisible and without taste, radon cannot be detected with the human senses. Radon is naturally occurring outside, but often is substantially concentrated indoors because homes are not normally built to be radon resistant. The potential for radon exposure varies by geographic areas; however, even buildings con- structed in areas considered to have low radon potential can exhibit greatly elevated radon concentrations. EPA Map of Radon Zones Highest Risk Higher Risk Medium Risk Guam: Preliminary Zone Designation Reducing the Risk From Radon | A Guide for Healthcare Providers 1 How Does Radon Enter the Home? Outdoors, where it is diluted to low concentrations in the air, radon poses significantly less risk than indoors. In the indoor air environment, however, radon can accumulate to high concentrations. The magnitude of radon concentration indoors depends primarily on a building’s construction and the amount of radon in the underlying soil. The soil composition under and around a house affects radon levels and the ease with which radon migrates toward a house. Normal pressure differences between the house and the soil often create a slight vacuum in the home that can draw radon gas from the soil into the building. Radon gas can enter a home from the soil through cracks in concrete floors and walls, floor drains, sump pumps, construction joints, and tiny cracks or pores in hollow-block walls.
    [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]
  • Assessment of Potential Radiological Population Health Effects from Radon in Liquefied Petroleum Gs
    EPA 520/1-75-002 XA04N2871 ASSESSMENT OF POTENTIAL RADIOLOGICAL POPULATION HEALTH EFFECTS FROM RADON IN LIQUEFIED PETROLEUM GS FNIS-XA-N--254 .X .N "ED r4), uj 7,0 t PROI U.S.ENVIRONMENTAL PROTECTION AGFNC I CD Office of Radiation Programs ASSESSMENT OF POTENTIAL RADIOLOGICAL POPULATION HEALTH EFFECTS FROM RADON IN LIQUEFIED PETROLEUM GAS 'I+-tells 'q ml Thomas F. Gesell Raymond H. Johnson, Jr. David E. Bernhardt FEBRUARY 1977 U.S. ENVIRONMENTAL PROTECTION AGENCY Office of Radiation Programs Washington, D.C. 20460 FOREWORD The Office of Radiation Programs carries out a national program designed to evaluate the exposure of man to ionizing and nonionizing radiation, and to promote development of controls necessary to pro- tect the public health and safety and assure environmental quality. Within the Office of Radiation Programs, the Environmental Assessment Division conducts programs relating to sources and levels of environmental radioactivity and the resulting population radiation dose. Results of these findings are published in appropriate scientific journals and Division technical reports. The technical reports of the Environmental Analysis Division allow comprehensive and rapid publishing of the results of intramural and contract projects. These reports are distributed to State and local radiological health programs, universities, libraries, information ser- vices, industry, hospitals, laboratories, technical and advisory committees to the Office of Radiation Programs, the press, and other interested groups and individuals. These reports are also included in the collections of the Library of Congress and the National Technical Information Service. Readers of these reports are encouraged to inform the Office of Radiation Programs of any omissions or errors.
    [Show full text]