NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

The program of studies and surveys of natural radiation and radioactivity in Spain organized by our research group at the end of the 1980s included a 4-y national survey to determine the concentrations of natural radionuclides in soil. Results obtained from measurements of soil samples collected nationwide at > 900 sampling sites are reported and discussed in this paper. Correlations between absorbed dose rates in air calculated from natural radionuclide concentrations in soil and terrestrial gamma dose rates measured experimentally outdoors are shown for the different autonomous regions of Spain. Assessment is also made of the dose to the Spanish population from outdoor exposure to terrestrial gamma rays.

Natural radioactivity in Spanish soils

Temporal changes of 7Be and 210Pb concentrations in surface air at temperate latitudes (40°N)

In this study, the authors considered the effect of soil moisture in the emanation process of radon and thoron gases. Weathered granite soil was selected as the test soil and it was packed in a polypropylene container (275 × 210mm2 and 100mm in height), up to 50mm in depth from the bottom. The container was covered with the exhalation rate measuring instrument adopting the accumulation method and γ-particles were counted at 30 s intervals for 30 min to estimate the exhalation rates. A sporadic increase in the radon and thoron exhalation rates was caused by the increase in the moisture content up to 8%. However, the exhalation rates showed a decreasing tendency with the increase in moisture content over 8%. Although the measured radon exhalation rate was about 25% of the calculated one, both measured and calculated radon exhalation rates had similar trends with an increase in the moisture content in the soil. The measured thoron exhalation rate agreed well with the calculated one. When the moisture content...

https://www.tandfonline.com/doi/pdf/10.1080/18811248.2007.9711855

Effect of Soil Moisture Content on Radon and Thoron Exhalation

Seasonal and spatial variation of atmospheric 210Pb and 7Be deposition: features of the Japan Sea side of Japan.

We found that increasing sunspot number caused a significant negative effect on monthly and yearly average air concentration and yearly deposition of 7Be. For more than 15 years monthly average surface air concentration and monthly deposition of 7Be was measured in Osaka, Japan. The maximum monthly average surface air concentration of 7Be was 1.6 times higher than the minimum concentration through the fifteen year measurement span. Increase of several percent in the monthly averaged surface air concentration and monthly deposition of 7Be were observed in the monthly mean for February-March-April 1987 period following the 23 February supernova explosion in the Large Magellanic Cloud. The seasonal variation pattern which includes the lowest surface air concentration of 7Be in summer is due to the transport of air masses from low latitudes carrying low 7Be concentrations into the middle latitude region.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999GL010801

Factors, especially sunspot number, causing variations in surface air concentrations and depositions of 7Be in Osaka, Japan

10年以上にわたって, 7Beの月間平均大気中濃度を堺で観測し, また, 大阪地区の2地点で7Be月間降下量を観測して, その結果を太陽黒点数の変化と比較した。7Beの月間大気中濃度は1.8-9.6mBq/m3の範囲であった。一方, 7Beの月間降下量は6.8-360Bq/m2の範囲を示した。1979年より'92年に至る大気中濃度の観測で, '87年に7Be年間濃度の上昇が認あられた。'87年の7Be最高濃度と'91年の最低濃度を比較したところ, 1.6倍に達していた。その結果, 平均的には全大気中濃度の36%は銀河宇宙線によるものとわかった。また, 2地点で観測した月間降下量の結果を用いて, 銀河宇宙線に起因したとみられる年間降下量を見積もった。南大阪における'87年の7Be降下量を約500Bq/m2と推測した。

Variation of 7Be Concentrations in Surface Air and in Deposition with the Solar Activity.

ダイオキシン対策を考え, その効果を把握し, ダイオキシン類の環境動態を検討するためには過去からのダイオキシン類の蓄積状態や発生源の変遷を知ることは重要である。本研究では, 琵琶湖および大阪湾で採取した底質コアを用いてダイオキシン類の歴史トレンド解析を行った。その結果, 琵琶底質では19世紀半ばの底質層にダイオキシン類の存在が認められ, その後, 20世紀後半に濃度が大きく増加している。そして, 1980年前後に観察されたピークから現在は若干の減少あるいは横這いの傾向が続いていることが示された。異性体や同族体の変化や主成分分析から底質ダイオキシン類の主要な汚染源は燃焼由来のPCDDs/DFsに加え, 除草剤CNPやPCP中に含まれていたPCDDs/DFsの影響があると考えられた。

Time Trends of PCDDs/DFs in Lake Biwa and Osaka Bay

Soil samples of surface layer were collected in Wakasa Bay area which is composed of various geologic properties. Concentrations of background radionuclides in soil samples were determined by γ-ray spectrometry with a coaxial type and a planer type of Ge(Li) detectors. The spectra of soil samples obtained by X-ray diffraction analysis show the characteristic composition of minerals based on the geologic properties of their mother's rocks. The concentrations of 238U, 226Ra, 228Ra and 40K in soil roughly correspond to the geologic properties. The highest concentrations of these four nuclides are the soil collected from granitic zone and next comes the soil from paleozoic zone. For homologous soil from granite and paleozoic the 40K contents decrease with increasing surface area, respectively. A good correlation between the 137Cs contents and the unsupported 210Pb contents was found in the soil samples of surface layer.

Background Radioactivity of Soil in Wakasa Bay Area (Southern Fukui Prefecture)

Each soil sample of more than 10kg (dry weight) was collected on three sites in southern part of Seta in Shiga prefecture and was separated into seven particle sizes. Each sieved soil sample was analyzed for the mineral compositions by means of X-ray diffraction and the concentrations of 238U, 226Ra, 228Ra and 40K by means of γ-ray spectrometry with Ge (Li) detectors. There were trends for the contents of anorthite (calcium-rich feldspar) decrease rapidly and those of albite (sodium-rich feldspar) and quartz to decrease slowly as particle size decreased. It is found that the concentrations of 238U, 226Ra, 210Pb and 228Ra increase with decreasing particle size and that of 40K decreases with decreasing particle size. It is concluded that for the soil weathered from a mother's rock the concentrations of 238U, 226Ra, 210Pb and 228Ra decrease with increasing the concentrations of 40K.

https://www.jstage.jst.go.jp/article/jhps1966/21/3/21_3_155/_pdf

Kazuko Megumi

Papers

Factors, especially sunspot number, causing variations in surface air concentrations and depositions of 7Be in Osaka, Japan

Variation of 7Be Concentrations in Surface Air and in Deposition with the Solar Activity.

Time Trends of PCDDs/DFs in Lake Biwa and Osaka Bay

Background Radioactivity of Soil in Wakasa Bay Area (Southern Fukui Prefecture)

Concentration of Natural Radioactive Nuclides and Mineral Compositions in Soil in Relation to Their Sizes