Cristina Nuccetelli

Natural radioactivity in building materials in the European Union: a database and an estimate of radiological significance

The authors set up a database of activity concentration measurements of natural radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) in building material. It contains about 10,000 samples of both bulk material (bricks, concrete, cement, natural- and phosphogypsum, sedimentary and igneous bulk stones) and superficial material (igneous and metamorphic stones) used in the construction industry in most European Union Member States. The database allowed the authors to calculate the activity concentration index I--suggested by a European technical guidance document and recently used as a basis for elaborating the draft Euratom Basic Safety Standards Directive--for bricks, concrete and phosphogypsum used in the European Union. Moreover, the percentage could be assessed of materials possibly subject to restrictions, if either of the two dose criteria proposed by the technical guidance were to be adopted.

Radioactivity in building materials: room model analysis and experimental methods.

First, models (room models) published in the international literature allowing the exposure to gamma radiation indoors due to building materials to be assessed are reviewed and discussed. For one of them, a sensitivity analysis concerning the effect of changing the parameters (e.g. dimensions of the room, thickness and density of the walls, etc.) used in calculations is performed. Second, a method is proposed for calculating the activity concentration in the walls of a room using: (a) the measured absorbed dose rate in air in the room; (b) the contributions of natural radionuclides (238U, 232Th and 40K) to the absorbed dose rate in air assessed by means of gamma spectrometry indoors; and (c) the specific dose rate (nGy h(-1) per Bq kg(-1)) of natural radionuclides, for the chosen room geometry, calculated with the room model.

A new accurate and flexible index to assess the contribution of building materials to indoor gamma exposure

The role of building materials as a source of gamma radiation has been recognized in the new EU Basic Safety Standards Directive which introduces an index I to screen building materials of radiological concern. This index was developed to account for average concrete values of thickness and density, the main structural characteristics of building materials that have an effect on gamma irradiation. Consequently, this screening procedure could be unfit in case of significantly different density and/or thickness of the building materials under examination. The paper proposes a more accurate and flexible activity concentration index, accounting for the actual density and thickness of building materials.

Natural radioactivity in building material in the European Union: robustness of the activity concentration index I and comparison with a room model

Using a wide database collected in the last 10 years, the authors have calculated the activity concentration index I for many building materials in the European Union. Suggested by a European technical guidance document, the index I has recently been adopted as a screening tool in the proposal for the new Euratom basic safety standards directive. The paper analyses the possible implications of the choice of different parameters for the computation of index I, i.e. background to be subtracted, dose criteria, etc. With the collected data an independent assessment of gamma doses was also made with an ISS room model, choosing reasonable hypotheses on the use of materials. The results of the two approaches, i.e. index I and a room model, were compared.

In situ gamma spectroscopy in environmental research and monitoring.

In situ gamma spectroscopy was introduced to determine the outdoor gamma dose rate from soil and to calculate the radionuclide concentration and the relative contribution to the dose rate. This paper reviews the most common and proven applications of in situ gamma spectroscopy-together with the most recent and innovative research outcomes obtained with this technique, particularly for its use indoors. Advantages and limitations of its utilization to assess environmental radioactivity-indoors and outdoors-are also discussed.

Radioactivity in drinking water: regulations, monitoring results and radiation protection issues

INTRODUCTION Drinking waters usually contain several natural radionuclides: tritium, radon, radium, uranium isotopes, etc. Their concentrations vary widely since they depend on the nature of the aquifer, namely, the prevailing lithology and whether there is air in it or not. AIMS In this work a broad overview of the radioactivity in drinking water is presented: national and international regulations, for limiting the presence of radioactivity in waters intended for human consumption; results of extensive campaigns for monitoring radioactivity in drinking waters, including mineral bottled waters, carried out throughout the world in recent years; a draft of guidelines for the planning of campaigns to measure radioactivity in drinking water proposed by the Environmental Protection Agency (ARPA) of Lombardia.

Updated database on natural radioactivity in building materials in Europe

The paper presents the latest collection of activity concentration data of natural radionuclides (226Ra, 232Th and 4 K) in building materials. This database contains about 24200 samples of both bulk materials and their constituents (bricks, concrete, cement, aggregates) and superficial materials used in most European Union Member States and some European countries. This collection also includes radiological information about some NORM residues and by-products (by-product gypsum, metallurgical slags, fly and bottom ashes and red mud) which can be of radiological concern if recycled in building materials as secondary raw materials. Moreover, radon emanation and radon exhalation rate data are reported for bricks and concrete.

A tentative method to evaluate the building material contribution to indoor gamma dose rate

Publisher Summary Building materials are an important source of indoor gamma dose rate, particularly in multistory buildings. In many cases in that, it is difficult to enter the dwellings to measure the indoor gamma dose rate, such as for epidemiological studies and surveys, it is actually interesting to estimate the indoor gamma dose rate. In this chapter a new method to estimate the indoor gamma dose rate attributable to the building materials are presented in this chapter, based on the outdoor measurements performed close to an external wall of a dwelling and a room model elaboration. The method was compared using data collected within the framework of the Italian Epidemiological study SETIL on the aetiology of childhood leukaemia, lymphoma and neuroblastoma. In this chapter preliminary result of a new approach to estimate indoor gamma dose rate due to the building materials is reported. Both analyzed methods give good results on average, but, due to a very simple but more accurate analysis of the indoor situation, the combined method based on experimental data plus room model elaboration seems to describe the indoor gamma exposure much better than the simple outdoor measurement.

From raw materials to NORM by-products

Abstract Naturally occurring radionuclides are present in the Earth crust; however, their distribution is not homogeneous. When primary or secondary raw materials containing relatively low concentrations of naturally occurring radionuclides are introduced in an industrial process then the radionuclides can become more concentrated in the produced (by-)products. For example, during the production of purified metals, throughout the purification process, also other elements, such as naturally occurring radionuclides, become concentrated in the by-products. In order to assure radiation protection of the population, it is important to map the potential exposure for workers and the general public. There is an extensive literature available regarding the presence of naturally occurring radionuclides in various by-products; however, it can be hard to review and even to interpret for the regulators and members of the industry in order to assure the safe use of by-products for example in construction. To solve this problem data mining and text processing have been applied to the ever-increasing numbers of publications (More than 39,000 filtered publications have been processed up to the Jan. 6, 2017), and the NORM4Building database has been compiled based on the analysis of the collected data. Based on this database using text analysis methods the most NORM prone raw materials and industries have been identified. This chapter gives a concise overview on the parameters to be considered during the selection of NORM by-products as feedstock for the construction industry, specifically for the production of cement, concrete, and ceramics. In the frame of this chapter the technical and radiological properties of the most representative industrial processes (such as coal mining and combustion; iron and steel production; the alumina, the zirconia, and the phosphate industry; etc.) and their by-products are discussed, especially considering the needs of the construction industry and the new European Basic Safety Standards.

Estonian waterworks treatment plants: clearance of residues, discharge of effluents and efficiency of removal of radium from drinking water.

Considerable levels of radium were detected in a certain fraction of the Estonian drinking water supply network. Some of these waterworks have treatment systems for the removal of (mainly) iron and manganese from drinking water. Three of these waterworks and another one equipped with a radium removal pilot plant were examined, and a specific study was conducted in order to assess the environmental compatibility of effluents and residues produced in the plants. (226)Ra and (228)Ra activity concentrations were analysed in both liquid (backwash water) and solid (sand filter and sediment) materials to evaluate their compliance, from the radiological point of view, with current Estonian legislation and international technical documents that propose reference levels for radium in effluents and residues. Also with regard to water treatment by-products, a preliminary analysis was done of possible consequences of the transposition of the European Basic Safety Standards Draft into Estonian law. Radium removal efficiency was also tested in the same plants. Iron and manganese treatment plants turned out to be scarcely effective, whilst the radium mitigation pilot plant showed a promising performance.