Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia

The risk of dangerous radon emissions in Estonia is high, being among the highest in Europe. In almost 33 per cent of Estonian land area, the content of radon in soil-contained air exceeds the safe limit for unrestricted construction (50 kBq/m 3 ). In such high radon-risk areas the concentration of radon in soil-contained air ranges from 50 to 400 kBq/m 3 , in a few cases reaching up to 2,100 kBq/m 3 exceeding the permitted level for residential areas. The situation is particu -larly serious in the northernmost part of the country, where uranium-rich graptolite argillite (Dictyonema shale) and the Obolus phosphorite are close to ground surface and their particles are constituent parts of Quaternary deposits. Radon emissions from bedrock have been investigated in detail, but to date Quaternary strata as a source of radon emissions are poorly studied. According to our measurements the highest concentrations of radon are related to tills containing clasts and fines of graptolite argillite and phosphorite. Glacial deposits include also granitoidal material, containing U, Th and K, which have been transported by glaciers from the outcrop areas of crystalline basement rocks in Finland and the Gulf of Finland. Due to weathering, outwash and repeated redeposition other genetic types are poorer in radioac -tive elements and they are weaker sources of radon

Современные методы определения радиоактивности почвы и риск воздействия природного излучения на население

Agenția Națională pentru Sănătate Publică, Chișinău, Agenția Internațională pentru Energie Atomică, Viena, Austria, Institutul de Geologie, Tallinn, EstoniaÎn lucrare sunt prezentate analizările cercetării radioactivității naturale în diverse tipuri de sol din trei regiuni din Estonia. Rezultatele denotă că concentrația din sol a radionuclizilor naturali studiați, în special a radonului, uraniului, toronului și potasiului, a variat în funcție de tipul și structura acestuia. Valori sporite ale radionuclizilor menționați au fost detectate în solurile din zona de nord a țării, bogate în roci și în sol argilos cu o cantitate de umiditate sporită, în comparație cu solurile de tip nisipos și calcaros, unde acești indici aveau valori mult mai joase.The paper presents the analysis of natural radioactivity research in various soil types in three regions of Estonia. The results indicate that the soil concentration of the studied radionuclides, especially radon, uranium, thoron and potassium, varied, depending on its type and structure. Increased levels of radionuclides mentioned above have been detected in soil in the North of the country, rich in rocks and in clayey soil with increased moisture content, compared to sandy and limestone soils, where these indices have been substantially diminished.В статье представлен анализ исследований естественной радиоактивности в различных типах почв трех регионах Эстонии. Результаты свидетельствуют о том, что концентрация в почве изучаемых радионуклидов, особенно радона, урана, торона и калия, варьировала в зависимости от ее типа и структуры. Повышенные уровни упомянутых радионуклидов были обнаружены в почве на севере страны, богатой камнями, и в глинистой почве с повышенным содержанием влаги, по сравнению с песчаными и известняковыми почвами, где эти показатели были существенно снижены

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose. This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations. This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity; • be informed about the levels of natural radioactivity caused by different sources; • have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor; • and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.JRC.G.10-Knowledge for Nuclear Security and Safet

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose.This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations.This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity;• be informed about the levels of natural radioactivity caused by different sources;• have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor;• and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.Additional information at: https://remon.jrc.ec.europa.eu/About/Atlas-of-Natural-Radiatio

Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia

The risk of dangerous radon emissions in Estonia is high, being among the highest in Europe. In almost 33 per cent of Estonian land area, the content of radon in soil-contained air exceeds the safe limit for unrestricted construction (50 kBq/m3). In such high radon-risk areas the concentration of radon in soil-contained air ranges from 50 to 400 kBq/m3, in a few cases reaching up to 2,100 kBq/m3 exceeding the permitted level for residential areas. The situation is particularly serious in the northernmost part of the country, where uranium-rich graptolite argillite (Dictyonema shale) and the Obolus phosphorite are close to ground surface and their particles are constituent parts of Quaternary deposits. Radon emissions from bedrock have been investigated in detail, but to date Quaternary strata as a source of radon emissions are poorly studied. According to our measurements the highest concentrations of radon are related to tills containing clasts and fines of graptolite argillite and phosphorite. Glacial deposits include also granitoidal material, containing U, Th and K, which have been transported by glaciers from the outcrop areas of crystalline basement rocks in Finland and the Gulf of Finland. Due to weathering, outwash and repeated redeposition other genetic types are poorer in radioactive elements and they are weaker sources of radon

Chapter 5: Radon

Natural ionising radiation is considered the largest contributor to the collective effective dose received by the world’s population. Man is continuously exposed to ionising radiation from several sources that can be grouped into two categories: first, high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and, second, radioactive nuclides generated when the Earth was formed and still present in its crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium (U) and thorium (Th) radioactive families together with potassium (40K), a long-lived radioactive isotope of the elemental potassium. In most cases, radon (222Rn), a noble gas produced by radioactive decay of the 238U progeny, is the major contributor to the total dose. This European Atlas of Natural Radiation has been conceived and developed as a tool for the public to become familiar with natural radioactivity; be informed about the levels of such radioactivity caused by different sources; and have a more balanced view of the annual dose received by the world’s population, to which natural radioactivity is the largest contributor. At the same time, it provides reference material and generates harmonised data, both for the scientific community and national competent authorities. Intended as an encyclopaedia of natural radioactivity, the Atlas describes the different sources of such radioactivity, cosmic and terrestrial, and represents the state-of-the art of this topic. In parallel, it contains a collection of maps of Europe showing the levels of natural sources of radiation. This work unfolds as a sequence of chapters: the rationale behind; some necessary background information; terrestrial radionuclides; radon; radionuclides in water and river sediments; radionuclides in food; cosmic radiation and cosmogenic radionuclides. The final chapter delivers the overall goal of the Atlas: a population-weighted average of the annual effective dose due to natural sources of radon, estimated for each European country as well as for all of them together, giving, therefore, an overall European estimate. As a complement, this introductory chapter offers an overview of the legal basis and requirements on protecting the public from exposure to natural radiation sources. In Europe, radiation has a long tradition. Based on the Euratom Treaty, the European Atomic Energy Community early established a set of legislation for protecting the public against dangers arising from artificial ('man-made') ionising radiation, but this scope has since been extended to include natural radiation. Indeed, the recently modernised and consolidated Basic Safety Standards Directive from 2013 contains detailed provisions on the protection from all natural radiation sources, including radon, cosmic rays, natural radionuclides in building material, and naturally occurring radioactive material