DOCSLIB.ORG

Use of Isotopic Signature of Radionuclides Released from Uranium Mines and Mills to Discriminate Low Levels of Environmental Impact Against Natural Background Levels

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Use of Isotopic Signature of Radionuclides Released from Uranium Mines and Mills to Discriminate Low Levels of Environmental Impact Against Natural Background Levels XA9745957 USE OF ISOTOPIC SIGNATURE OF RADIONUCLIDES RELEASED FROM URANIUM MINES AND MILLS TO DISCRIMINATE LOW LEVELS OF ENVIRONMENTAL IMPACT AGAINST NATURAL BACKGROUND LEVELS P. ZETTWOOG, N. LEMAITRE Office de protection contre les rayonnements Ionisants, Le Vesinet S. BERNHARD, Y. VAUZELLE ALGADE, Bessines sur Gartempe France Abstract In France, uranium ores have been exploited in rural areas with a low population density. The critical population group which is identified for radiological impact studies lives close to the uranium facilities, at distances from a few hundred metres to 1 kilometre. Within this range, the radioactivity of the environment is still detectable amongst the natural background. Mining companies manage surveillance networks according to strict specifications laid down by the government authorities. For active mining operations it is the exposure to daughter products of radon 222 that forms the bulk of the total effective dose. After closure of a mine and rehabilitation of the site, products such as uranium 238 and radium 226 in the water can become the major components of the total effective dose. Surveillance networks are built to allow direct measurement of the radon daughter products critical to the alpha energy and measurements of the water activities for uranium 238 and radium 226. Annual limits for the effective individual doses are given and determined by the authorities. The industry must manage effective annual doses of the order of 1 mSv. The natural exposure which is not part of the regulation is of the same order (1 mSv) as the exposure created by the industry. The results given are therefore lacking in clarity for the public. The Office de Protection contre les Rayonnements Ionisants (OPRI) and ALGADE are developing methods which allow differentiation between natural phenomena and man-made phenomena. It has been recognised that for a region where mining activities have taken place, the isotopic signature of uranium, radium and radon can clearly be recognised from the same product of natural origin. In the case of radon, for example, the industry produces only radon 222 while natural emanations are composed of radon 220 and radon 222. 1. FRENCH REGULATIONS RELATING TO ENVIRONMENTAL PROTECTION AT URANIUM MINES 1.1. Historical background In France, the legal document specifically covering environmental protection around uranium mines, ore treatment plants, storage plants for mining waste and solid waste from treatment is Decree no 90-222 of 9 March 1990. The decree was published in the Official Journal of the French Republic of 13 March 1990, and was introduced into the general regulations governing the extractive industries brought into force by Decree no 80-331 of 7 May 1980. Arrangements for monitoring waste disposal and measuring the exposure of the general population to ionising radiation were progressively put into place by the producers from the beginning of the 1970s under their own initiative, the design of these arrangements being based on the recommendations of international organisations in force at the time. For the most part, the above document ratifies these arrangements. Among the documents used as reference material by those drafting Decree no 90-222 were AIEA SS no 43 of 1975 [1] (which laid down the objectives of surveillance networks) and ICRP Publication no 43 [2] of 1984. The latter publication confirmed that the objectives of document SS 337 no 43 were sound, clarified a few important concepts, among them that of "critical population groups" already introduced in ICRP Publication no 26 [3], and endorsed two types of monitoring strategy: those aimed at qualifying environmental impact via a determination of sources and transfers, and those aimed at direct estimates of the exposure of populations. 1.2 The key points in Decree no 90-222 Decree no 90-222 is based on the concept of "critical population groups". Its objective is to limit the fraction of their annual exposure attributable to the "industrial" discharges of mining companies and plants that depend on them. The "critical population groups" are identified during the radiological study of the site carried out prior to the establishment of the surveillance network, taking into account the sources and critical transfer routes of the radionuclides significant for radiological protection. Specific Prefectorial Orders specify the frequency and siting of the sampling points in the environment and the methods of measurement to be used. As regards the radioactivity contained in drainage water discharged from mines and in liquid effluent from industrial plants, the decree introduces the principle of optimising radiological protection. The limits for discharge are fairly severe as regards both the dilution provided by the waterway receiving it and the possible transfer routes. If there is a demand that a radium or uranium purification station is necessary, the operator must use the best available technology leading to the smallest possible discharge. 1.3. Annual dose limits introduced in the circulaire d 'application (memorandum of application) A circulaire d 'application lays down the limits to be complied with as regards the effective dose equivalent added by industry to that of natural origin for the same radionuclides and the same exposure routes. Except for special cases, the effective dose is determined by taking into account the exposure to gamma radiation, the inhalation of short-lived daughter products of radon isotopes and of long-lived alpha emitters in radioactive dust, the consumption of water at the site and the local food produced. At present (May 1996), the annual limit for the effective dose equivalent for people belonging to the critical population group is 5 mSv. It is assumed in the calculation that 5 mSv corresponds to the inhalation of a potential alpha energy (PAE) of 2 mJ due to the daughter products of radon 222, 6 mJ due to those of radon 220, 170 Bq due to ore dust, and to the ingestion of 7000 Bq of radium 226 and 2 g of natural uranium. In the near future, the circulaire a"application will in all probability have to legalise a limit on the effective dose equivalent of 1 mSv per year averaged over 5 years, a limit that the EU is preparing to introduce officially into its directives. The value of 1 mSv will correspond in particular to the ingestion of a PAE of 0.73 mJ from radon 222 daughter products. This quantity is inhaled by a person exposed for a year to an equilibrium radon 222 concentration of 18 Bq m'3, the concentration expressed as a PAE being about 100 nJ m3. 338 2. PROBLEMS ENCOUNTERED BY THE OPERATORS IN APPLYING DECREE NO 90-222 2.1. Current situation After discussion, operators have accepted and implemented the arrangements included in the Prefectorial Orders for the monitoring of discharges and the surveillance networks. It turns out that the value of the effective dose equivalent corresponding to the combination of "industrial" and "natural" exposures is in general less than the annual limit of 5 mSv. Everything is thus fine, and there are no problems still to be solved. In order to recover the contribution of "industrial" origin, the operator subtracts a fixed value for the "natural background" from the total. Since even the total dose falls within the legal limit, the operator is not very particular about the way in which this natural background is determined. To ease matters, he adopts values measured relatively distant from the industrial sources, which are more representative of the regional background than of the local background at the mine workings being monitored and thus possibly too low. This could lead to an overestimate of the industrial component. 2.2. The current annual limit of 1 mSv The total exposure at mines leads in general to an effective dose for populations of more than 1 mSv per year. With the present arrangements for monitoring discharges and the release of solid waste by containment facilities, it might be impossible at some sites to comply with a limit on the industry-related annual effective dose equivalent of 1 mSv (with the above-mentioned corresponding value for radon 222) for all critical groups. The operator should clearly improve his containment facilities, and he is in fact quite prepared to do this provided, however, he is convinced that in his case the limit is not complied with. The operator sees that the natural background is of the same order as the statutory limit and is often greater than the legal industrial contribution. He will have to produce sound arguments for the natural background values that, at the moment, he will have calculated at most just before subtracting them from the total values. The introduction of a stricter limit reveals a problem which has not existed so far: that of discriminating between contributions from natural sources and those from industrial sources in the total effective doses. In the case of mines, using the regional background is not in general adequate. This is because the radioactive atmospheric load of radon 222 due to its exhalation from local soils varies considerably on a local scale, depending as it does on the ventilation capacity and the weather conditions. High values obtained at a station do not necessarily indicate that it is marked by radon of industrial origin. It could simply be a case of a station installed in a poorly ventilated location. Similarly, the radioactive load of natural origin in underground and surface waters, observed in the catchment area of the mine, corresponds to a geological formation which contained an anomalously high uranium concentration. Such a radioactive load of natural origin may be very different from that observed in another catchment area nearby having the same geology but never having contained a uranium deposit. It is therefore essential to find a method of discriminating between the two contributions which is based on measurements made on the scale of the site being monitored and not on any measurements made elsewhere.
Load more

Recommended publications
  • Progress and Challenges in Using Stable Isotopes to Trace Plant Carbon and Water Relations Across Scales
    Biogeosciences, 9, 3083–3111, 2012 www.biogeosciences.net/9/3083/2012/ Biogeosciences doi:10.5194/bg-9-3083-2012 © Author(s) 2012. CC Attribution 3.0 License. Progress and challenges in using stable isotopes to trace plant carbon and water relations across scales C. Werner1,19, H. Schnyder2, M. Cuntz3, C. Keitel4, M. J. Zeeman5, T. E. Dawson6, F.-W. Badeck7, E. Brugnoli8, J. Ghashghaie9, T. E. E. Grams10, Z. E. Kayler11, M. Lakatos12, X. Lee13, C. Maguas´ 14, J. Ogee´ 15, K. G. Rascher1, R. T. W. Siegwolf16, S. Unger1, J. Welker17, L. Wingate18, and A. Gessler11 1Experimental and Systems Ecology, University Bielefeld, 33615 Bielefeld, Germany 2Lehrstuhl fur¨ Grunlandlehre,¨ Technische Universitat¨ Munchen,¨ 85350 Freising-Weihenstephan, Germany 3UFZ – Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany 4University of Sydney, Faculty of Agriculture, Food and Natural Resources, 1 Central Avenue, Eveleigh, NSW 2015, Australia 5College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Admin Bldg, Corvallis (OR), USA 6Center for Isotope Biogeochemistry, Department of Integrative Biology, University of California, Berkeley, CA 94720, USA 7Potsdam Institute for Climate Impact Research (PIK) PF 60 12 03, 14412 Potsdam, Germany 8CNR – National Research Council of Italy – Institute of Agro-environmental and Forest Biology, via Marconi 2, 05010 Porano (TR), Italy 9Laboratoire d’Ecologie, Systematique´ et Evolution (ESE), CNRS AgroParisTech – UMR8079, Batimentˆ 362, Universite´ de Paris-Sud (XI), 91405 Orsay Cedex, France 10Ecophysiology of Plants, Department of Ecology and Ecosystem Management, Technische Universitat¨ Munchen,¨ Von-Carlowitz-Platz 2, 85354 Freising, Germany 11Institute for Landscape Biogeochemistry Leibniz-Zentrum fur¨ Agrarlandschaftsforschung (ZALF) e.V., Eberswalderstr.
    [Show full text]
  • Oxygen Isotopic Signature of CO2 from Combustion Processes
    Atmos. Chem. Phys., 11, 1473–1490, 2011 www.atmos-chem-phys.net/11/1473/2011/ Atmospheric doi:10.5194/acp-11-1473-2011 Chemistry © Author(s) 2011. CC Attribution 3.0 License. and Physics Oxygen isotopic signature of CO2 from combustion processes M. Schumacher1,2,3, R. A. Werner3, H. A. J. Meijer1, H. G. Jansen1, W. A. Brand2, H. Geilmann2, and R. E. M. Neubert1 1Centre for Isotope Research, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands 2Max-Planck-Institute for Biogeochemistry, Hans-Knoell-Straße 10, 07745, Jena, Germany 3Institute of Plant Sciences, Swiss Federal Institute of Technology Zurich,¨ Universitatsstraße¨ 2, 8092 Zurich,¨ Switzerland Received: 21 July 2008 – Published in Atmos. Chem. Phys. Discuss.: 5 November 2008 Revised: 2 February 2011 – Accepted: 5 February 2011 – Published: 16 February 2011 Abstract. For a comprehensive understanding of the global (diffusive) transport of oxygen to the reaction zone as the carbon cycle precise knowledge of all processes is neces- cause of the isotope fractionation. The original total 18O sig- sary. Stable isotope (13C and 18O) abundances provide in- nature of the material appeared to have little influence, how- formation for the qualification and the quantification of the ever, a contribution of specific bio-chemical compounds to diverse source and sink processes. This study focuses on the individual combustion products released from the involved 18 δ O signature of CO2 from combustion processes, which material became obvious. are widely present both naturally (wild fires), and human in- duced (fossil fuel combustion, biomass burning) in the car- bon cycle. All these combustion processes use atmospheric 1 Introduction oxygen, of which the isotopic signature is assumed to be con- stant with time throughout the whole atmosphere.
    [Show full text]
  • Uranium Fact Sheet
    Fact Sheet Adopted: December 2018 Health Physics Society Specialists in Radiation Safety 1 Uranium What is uranium? Uranium is a naturally occurring metallic element that has been present in the Earth’s crust since formation of the planet. Like many other minerals, uranium was deposited on land by volcanic action, dissolved by rainfall, and in some places, carried into underground formations. In some cases, geochemical conditions resulted in its concentration into “ore bodies.” Uranium is a common element in Earth’s crust (soil, rock) and in seawater and groundwater. Uranium has 92 protons in its nucleus. The isotope2 238U has 146 neutrons, for a total atomic weight of approximately 238, making it the highest atomic weight of any naturally occurring element. It is not the most dense of elements, but its density is almost twice that of lead. Uranium is radioactive and in nature has three primary isotopes with different numbers of neutrons. Natural uranium, 238U, constitutes over 99% of the total mass or weight, with 0.72% 235U, and a very small amount of 234U. An unstable nucleus that emits some form of radiation is defined as radioactive. The emitted radiation is called radioactivity, which in this case is ionizing radiation—meaning it can interact with other atoms to create charged atoms known as ions. Uranium emits alpha particles, which are ejected from the nucleus of the unstable uranium atom. When an atom emits radiation such as alpha or beta particles or photons such as x rays or gamma rays, the material is said to be undergoing radioactive decay (also called radioactive transformation).
    [Show full text]
  • Investigations of Nuclear Forensic Signatures in Uranium Bearing Materials a Dissertation Submitted to the Graduate School of the University of Cincinnati
    Investigations of Nuclear Forensic Signatures in Uranium Bearing Materials A dissertation submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Ph.D) In the Department of Chemistry Of the McMicken College of Arts and Sciences By Lisa Ann Meyers B.S. Ohio Northern University 2009 August 2013 Committee Chairs: Thomas Beck, Ph.D. Apryll Stalcup, Ph.D. i Abstract Nuclear forensics is a multidisciplinary science that uses a variety of analytical methods and tools to investigate the physical, chemical, elemental, and isotopic characteristics of nuclear and radiological material. A collection of these characteristics is called signatures that aids in determining how, where and when the material was manufactured. Radiological chronometry (i.e., age dating) is an important tool in nuclear forensics that uses several methods to determine the length of time that has elapsed since a material was last purified. For example, the “age” of a uranium-bearing material is determined by measuring the ingrowth of 230Th from its parent, 234U. A piece of scrap uranium metal bar buried in the dirt floor of an old, abandoned metal rolling mill was analyzed using multi-collector inductively coupled plasma mass spectroscopy (MC-ICP- MS). The mill rolled uranium rods in the 1940s and 1950s. The age of the metal bar was determined to be 61 years at the time of analysis using the 230Th/234U chronometer, which corresponds to a purification date of July 1950 ± 1.5 years. Radiochronometry was determined for three different types of uranium metal samples.
    [Show full text]
  • 12 Natural Isotopes of Elements Other Than H, C, O
    12 NATURAL ISOTOPES OF ELEMENTS OTHER THAN H, C, O In this chapter we are dealing with the less common applications of natural isotopes. Our discussions will be restricted to their origin and isotopic abundances and the main characteristics. Only brief indications are given about possible applications. More details are presented in the other volumes of this series. A few isotopes are mentioned only briefly, as they are of little relevance to water studies. Based on their half-life, the isotopes concerned can be subdivided: 1) stable isotopes of some elements (He, Li, B, N, S, Cl), of which the abundance variations point to certain geochemical and hydrogeological processes, and which can be applied as tracers in the hydrological systems, 2) radioactive isotopes with half-lives exceeding the age of the universe (232Th, 235U, 238U), 3) radioactive isotopes with shorter half-lives, mainly daughter nuclides of the previous catagory of isotopes, 4) radioactive isotopes with shorter half-lives that are of cosmogenic origin, i.e. that are being produced in the atmosphere by interactions of cosmic radiation particles with atmospheric molecules (7Be, 10Be, 26Al, 32Si, 36Cl, 36Ar, 39Ar, 81Kr, 85Kr, 129I) (Lal and Peters, 1967). The isotopes can also be distinguished by their chemical characteristics: 1) the isotopes of noble gases (He, Ar, Kr) play an important role, because of their solubility in water and because of their chemically inert and thus conservative character. Table 12.1 gives the solubility values in water (data from Benson and Krause, 1976); the table also contains the atmospheric concentrations (Andrews, 1992: error in his Eq.4, where Ti/(T1) should read (Ti/T)1); 2) another category consists of the isotopes of elements that are only slightly soluble and have very low concentrations in water under moderate conditions (Be, Al).
    [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]
  • Can Algal Photosynthetic Inorganic Carbon Isotope Fractionation Be Predicted in Lakes Using Existing Models?
    Aquat. Sci. 68 (2006) 142–153 1015-1621/06/020142-12 DOI 10.1007/s00027-006-0818-5 Aquatic Sciences © Eawag, Dübendorf, 2006 Research Article Can algal photosynthetic inorganic carbon isotope fractionation be predicted in lakes using existing models? Darren L. Bade1,3,*, Michael L. Pace2, Jonathan J. Cole2 and Stephen R. Carpenter1 1 Center for Limnology, University of Wisconsin-Madison, USA 2 Institute of Ecosystem Studies, Millbrook, NY, USA 3 Present address: Institute of Ecosystem Studies, PO Box AB (65 Sharon Turnpike), Millbrook, NY 12545, USA Received: 30 June 2005; revised manuscript accepted: 7 December 2005 Abstract. Differential fractionation of inorganic carbon stable isotopes for studies ranging from food webs to stable isotopes during photosynthesis is an important paleolimnology. In our largest comparative study, values cause of variability in algal carbon isotope signatures. of δ13C-POC ranged from –35.1 ‰ to –21.3 ‰. Using Several physiological models have been proposed to ex- several methods to obtain an algal isotopic signature, we ε plain algal photosynthetic fractionation factors ( p). These found high variability in fractionation among lakes. There ε models generally consider CO2 concentration, growth was no relationship between p and one of the most im- rate, or cell morphometry and have been supported by portant predictors in existing models, pCO2. A whole-lake empirical evidence from laboratory cultures. Here, we inorganic 13C addition was used to create distinct algal ε explore the applicability of these models to a broad range isotope signatures to aid in examining p. Measurements of lakes with mixed phytoplankton communities. Under- and a statistical model from the isotope addition revealed standing this fractionation is necessary for using carbon that algal fractionation was often low (0 – 15 ‰).
    [Show full text]
  • 1 Introduction
    1 Introduction WHO commissions reviews and undertakes health risk assessments associated with exposure to potentially hazardous physical, chemical and biological agents in the home, work place and environment. This monograph on the chemical and radiological hazards associated with exposure to depleted uranium is one such assessment. The purpose of this monograph is to provide generic information on any risks to health from depleted uranium from all avenues of exposure to the body and from any activity where human exposure could likely occur. Such activities include those involved with fabrication and use of DU products in industrial, commercial and military settings. While this monograph is primarily on DU, reference is also made to the health effects and behaviour of uranium, since uranium acts on body organs and tissues in the same way as DU and the results and conclusions from uranium studies are considered to be broadly applicable to DU. However, in the case of effects due to ionizing radiation, DU is less radioactive than uranium. This review is structured as broadly indicated in Figure 1.1, with individual chapters focussing on the identification of environmental and man-made sources of uranium and DU, exposure pathways and scenarios, likely chemical and radiological hazards and where data is available commenting on exposure-response relationships. HAZARD IDENTIFICATION PROPERTIES PHYSICAL CHEMICAL BIOLOGICAL DOSE RESPONSE RISK EVALUATION CHARACTERISATION BACKGROUND EXPOSURE LEVELS EXPOSURE ASSESSMENT Figure 1.1 Schematic diagram, depicting areas covered by this monograph. It is expected that the monograph could be used as a reference for health risk assessments in any application where DU is used and human exposure or contact could result.
    [Show full text]
  • Sources of Variation in the Stable Isotopic Composition of Plants*
    CHAPTER 2 Sources of variation in the stable isotopic composition of plants* JOHN D. MARSHALL, J. RENÉE BROOKS, AND KATE LAJTHA Introduction The use of stable isotopes of carbon, nitrogen, oxygen, and hydrogen to study physiological processes has increased exponentially in the past three decades. When Harmon Craig (1953, 1954), a geochemist and early pioneer of natural abundance stable isotopes, fi rst measured isotopic values of plant materials, he found that plants tended to have a fairly narrow δ13C range of −25 to −35‰. In these initial surveys, he was unable to fi nd large taxonomic or environmental effects on these values. Since that time ecologists have identi- fi ed clear isotopic signatures based not only on different photosynthetic pathways, but also on ecophysiological differences, such as photosynthetic water-use effi ciency (WUE) and sources of water and nitrogen used. As large empirical databases have accumulated and our theoretical understanding of isotopic composition has improved, scientists have continued to discover mismatches between theoretical and observed values, as well as confounding effects from sources and factors not previously considered. In the best tradi- tion of science, these discoveries have led to important new insights into physiological or ecological processes, as well as new uses of stable isotopes in plant ecophysiology. This chapter reviews the most common applications of stable isotope analysis in plant ecophysiology. Carbon isotopes Photosynthetic pathways 13 Plants contain less C than the atmospheric CO2 on which they rely for photosynthesis. They are therefore “depleted” of 13C relative to the atmo- sphere. This depletion is caused by enzymatic and physical processes that discriminate against 13C in favor of 12C.
    [Show full text]
  • Lead Isotope Determinations by Inductively-Coupled Plasma Mass Spectrometry (ICP-MS): Potential of Sector Field Instruments
    NGU-BULL 436, 2000 - PAGE 203 Lead isotope determinations by inductively-coupled plasma mass spectrometry (ICP-MS): potential of sector field instruments BELINDA FLEM, ANDREAS GRIMSTVEDT & NIGEL COOK Flem, B., Grimstvedt, A. & Cook, N.J. 2000: Lead isotope determinations by inductively-coupled plasma mass spectrometry (ICP-MS): potential of sector field instruments. Norges geologiske undersøkelse Bulletin 436, 203-207. Lead isotope measurements have been carried out using a high-resolution inductively-coupled plasma mass spectrometer (Finnigan MAT ELEMENT, configured with CD-1 option). The method can be applied to all types of geological samples brought into solution form. Three common lead standards are used for documentation of the method. Detection limits for 204Pb, 206Pb, 207Pb and 208Pb lie between 0.124 and 2.86 pg ml-1. Optimisation of scanning conditions at a count rate of approximately 200,000 cps for 206Pb and 207Pb, led to a relative standard deviation of 0.05% for the mean 207Pb/206Pb isotope ratio, based on 15 consecutive measurements. The method can be routinely applied to gain geochronological and petrological data for genetic studies of mineral deposits, including deposits of industrial minerals. Because of space charge effects in the skimmer cone region and mass-dependent sensitivity of the mass spectrometer, the measured intensity ratio of samples must generally be calibrated using external or internal standards of known isotope ratios to correct for mass biases and mass fractionation. Belinda Flem, Andreas Grimstvedt & Nigel Cook, Geological Survey of Norway, N-7491 Trondheim, Norway. which the Pb isotope systematics have been reset. The appli- Introduction cation of Pb isotopes for geochronology has declined in pop- Geochronological, isotopic and petrological data are impor- ularity in recent years.
    [Show full text]
  • Lead Isotopes, Metal Sources, Smelters, Precipitation, Toxic Release Inventory
    Coupling Meteorology, Metal Concentrations, and Pb Isotopes for Source Attribution in Archived Precipitation Samples Joseph R. Graneya*, Matthew S. Landisb aGeological Sciences and Environmental Studies, Binghamton University, Binghamton, NY USA 13902 bU.S. EPA Office of Research and Development, Research Triangle Park, NC USA 27709 *Corresponding author: Telephone: 607 777 6347 Fax: 607 777 2288 Postal Address: Department of Geological Sciences and Environmental Studies P.O. Box 6000 Binghamton University Binghamton, NY 13902-6000 E-mail address: [email protected] 1 Abstract A technique that couples lead (Pb) isotopes and multi-element concentrations with meteorological analysis was used to assess source contributions to precipitation samples at the Bondville, Illinois USA National Trends Network (NTN) site. Precipitation samples collected over a 16 month period (July 1994 - October 1995) at Bondville were parsed into six unique meteorological flow regimes using a minimum variance clustering technique on back trajectory endpoints. Pb isotope ratios and multi-element concentrations were measured using high resolution inductively coupled plasma – sector field mass spectrometry (ICP-SFMS) on the archived precipitation samples. Bondville is located in central Illinois, ~ 250 km downwind from Pb smelters in southeast Missouri. The Mississippi Valley Type ore deposits in Missouri provided a unique multi-element and Pb isotope fingerprint for smelter emissions which could be contrasted to industrial emissions from the Chicago and Indianapolis urban areas (~ 125 km north and east, of Bondville respectively); and regional emissions from electric utility facilities. Significant differences in Pb isotopes and element concentrations in precipitation varied according to the meteorological clusters. Industrial sources from urban areas, and thorogenic Pb from coal use, could be differentiated from smelter emissions from Missouri by coupling Pb isotope ratios with multi-element concentrations in precipitation.
    [Show full text]
  • Highly Enriched Uranium: Striking a Balance
    OFFICIAL USE ONLY - DRAFT GLOSSARY OF TERMS APPENDIX F GLOSSARY OF TERMS Accountability: That part of the safeguards and security program that encompasses the measurement and inventory verification systems, records, and reports to account for nuclear materials. Assay: Measurement that establishes the total quantity of the isotope of an element and the total quantity of that element. Atom: The basic component of all matter. Atoms are the smallest part of an element that have all of the chemical properties of that element. Atoms consist of a nucleus of protons and neutrons surrounded by electrons. Atomic energy: All forms of energy released in the course of nuclear fission or nuclear transformation. Atomic weapon: Any device utilizing atomic energy, exclusive of the means for transportation or propelling the device (where such means is a separable and divisible part of the device), the principal purpose of which is for use as, or for development of, a weapon, a weapon prototype, or a weapon test device. Blending: The intentional mixing of two different assays of the same material in order to achieve a desired third assay. Book inventory: The quantity of nuclear material present at a given time as reflected by accounting records. Burnup: A measure of consumption of fissionable material in reactor fuel. Burnup can be expressed as (a) the percentage of fissionable atoms that have undergone fission or capture, or (b) the amount of energy produced per unit weight of fuel in the reactor. Chain reaction: A self-sustaining series of nuclear fission reactions. Neutrons produced by fission cause more fission. Chain reactions are essential to the functioning of nuclear reactors and weapons.
    [Show full text]