Radiological impact of surface water and sediment near uranium mining sites

The aim of this study is to assess the radiological impact of surface water and sediment around uranium mining sites 20 years after their closing. The areas under observations are 31 former classical underground uranium mining and exploratory sites in Bulgaria, named as objects. The extraction and processing of uranium ores in the Republic of Bulgaria were ended in 1992. To assess the radiological impact of radionuclides field expeditions were performed to sample water and bottom sediment. The migration of uranium through surface water was examined as one of the major pathways for contamination spread. The range of uranium concentration in water flowing from the mining sites was from 0.012 to 6.8 mgU l −1 with a geometric mean of 0.192 mgU l . The uranium concentrations in water downstream the mining sites were approximately 3 times higher than the background value (upstream). The concentrations of U nat , 226 Ra, 210 Pb, and 232 Th in the sediment of downstream river were higher than those upstream by 3.4, 2.6, 2, and 1.7 times, respectively. The distribution coefficient of uranium reflects its high mobility in most of the sites. In order to evaluate the impact on people as well as site prioritization for more detailed assessment and water management, screening dose assessments were done

Results of the national radon indoors survey in Bulgaria

Purpose: To present the results of the annual average indoor radon concentrations from National survey in Bulgarian regions. Variability of measured data between 28 regions was investigated in order to achieve the preliminary assessment the distribution of indoor radon concentration through Bulgarian territory. Argument: The National survey on average radon concentration in Bulgarian dwellings was carried out from 2015 to 2016, with the co-operation of the Regional Health Inspectorate under the National Radon Program. Data were collected through personal interviews with residents and deployment of alpha track detectors for one year through two phases. The first phase was from March 2015 to December 2015 and second from December 2015 to April 2016 approximately. For each region 100 detectors were distributed and spread to villages in regions depending on the population. The measurements were completed in 2775 dwellings. The distribution of indoor radon levels has been found to be log-normal with a geometric mean (GM) of 81.6 Bq•m−3 and a standard deviation of 2.1. The highest value of the radon concentration found was 1314 Bq•m−3 in the Sliven region. Region with high GM of 184 Bq•m−3 and a standard deviation of 1.7 is Yambol in Southeast Bulgaria. In about 6% of the houses, the radon concentration was found to be in excess of the recommended reference value of 300 Bq•m−3, suggested by the Council of the European UnionCommission in in new EU Directive 2013/59/Euratom. Conclusion: The data from National survey are the first systematic results and are received to complete the National Program, which will finish in 2017. The preliminary results clearly show that the national action plan to address long-term risks from radon exposures should be developed taking into account the results achieve in this program and in accordance with the new Directive 2013/59/Euratom

Analysis of the spatial distribution of the indoor radon concentration in school's buildings in Plovdiv province, Bulgaria

This paper presents an evaluation of the indoor radon spatial variation between and within school buildings. Radon measurements were carried out in 331 rooms of 16 school buildings in 5 municipalities of Plovdiv province, Bulgaria. They were performed with CR-39 nuclear track detectors exposed over an 8-month period from September 2018 to April 2019. The arithmetic and geometric means together with corresponding standard deviation and geometric standard deviations of the indoor radon concentration were 160 ± 175 Bq/m3 and 108 */2.35 Bq/m3, respectively. The best data fit was achieved with a Weibull 3-parameter function (Kolmogorov-Smirnov test, p = 0.2916). The effect of the school location and various building characteristics on the indoor radon concentration distribution within a province was investigated. The analyses showed that the factor “year of building construction”, which is in general related with the technical condition of the building, imposed the highest impact on the indoor radon concentration difference between schools. The vertical and horizontal components of the indoor radon spatial variability within a school were analysed as well. The results concerning the radon variation within schools could be used to optimize future radon school surveys. In this paper, quality control for indoor radon measurement procedures and radon health impact assessments was included

MEASUREMENTS OF RADON CONCENTRATION IN SOIL GAS OF URBAN AREAS, BULGARIA

These work present results of preliminary study of radon concentration in soil gas at 64 locations within 13 urban areas of Bulgaria using AlphaGuard equipment. The measuring period was from 2008 to 2012. The temperature and humidity has been measured as well, including the gamma dose rate. The radon concentration in soil gas was found to be log-normally distributed within the range from 3-97 kBq.m −3 , with arithmetic mean of 26 kBq.m −3 . The influence of the meteorological and geological factors in relation to radon measurements was examined. Correlation between radon in soil gas and gamma dose rate was also present

Exposure Due to Indoor Radon in Bulgarian Schools

Indoor radon exposure is the largest contributor to population dose from natural sources. Radon as a natural radioactive gas could accumulate to harmful levels in buildings, such as homes and buildings with public access. In order to assess the exposure due to radon in school the results of indoor radon measurements in 55 state school buildings in 7 municipalities located in one district in southern Bulgaria are considered in this paper. The survey was carried out with passive CR-39 etched track detectors. Radon concentrations ranged from 17 to 868 Bq m–3 , with a geometric mean of 117 Bq m–3 and a geometric standard deviation of 1.78. The findings revealed that in 30% of the measured buildings the radon concentration was higher than the national reference level of 300 Bq m–3 . The statistically significant difference in indoor radon concentrations between municipalities (KW, р < 0.001) was obtained. The research was also focused on parameters affecting radon concentration levels such as type of room and floor location. The estimated annual effective dose of 0.39 to 1.07 mSv y–1 , applying the ICRP and UNSCEAR methodology, was calculated for students. The results of the measurements were provided to the administrative authorities and measures were proposed to improve the air in school buildings with high radon levels

Analysis of exposure to radon in Bulgarian rehabilitation hospitals

Mineral springs are used in spa resorts throughout the world. Radon is a natural radioactive source, which can dissolve, accumulate, and be transported by water. This study investigates the radon concentration in air and water in 12 Bulgarian rehabilitation hospitals and presents the assessment of the exposure to radon in them. The measurements were performed at 401 premises within 21 buildings, using two types of passive detectors for a dry and wet environment that were exposed from February, 2019 to June, 2019. The radon concentration varied from 19 to 2550 Bq/m3 with an arithmetic mean and a standard deviation of 102 Bq/m3 and 191 Bq/m3, respectively. The hypothesis that in hospitals the source of radon, besides soil under the buildings, is also the mineral water that is used for treatment was tested. Thermal water samples were procured sequentially from a spring and baths to analyse the

Continuous measurements of radon and radon progeny in various public places

The exposure to radon in buildings open to the public and at workplaces depends on many factors, for example, forms of utilization, construction conditions, time of exposure, heating, and ventilation conditions, etc. To evaluate the radon exposure in different working environments, continuous simultaneous measurements of radon (CRn), equilibrium equivalent (EEC), and potential alpha energy (PAEC) concentrations for 24 hours were performed using AlphaE for CRn and DOSEman PRO from SARAD GmbH for EEC and PAEC measurements. The study considered measurements at three locations in the radon-rich spa of Narechen, Asenovgrad, and at an old mine turned museum in the town of Pernik. A comparison was made between the average values of the concentrations relating to all-day and only working hours when the measurements were completed. The CRn increases during the working hours in the museum as well as in the bath of the spa, while it decreases in the spa’s treatment room. On the other hand, the EEC and PAEC are increasing at all locations. The concentrations increasing due to working hours, which are integrated into long-term measurements can cause underestimated radon exposures in radon reach working environment

Prediction of Long-Term Indoor Radon Concentration Based on Short-Term Measurements

We present a method for the estimation of annual radon concentration based on short-term (three months) measurements. The study involves results from two independent sets of indoor radon concentration measurements performed in 16 cities of the Republic of Macedonia. The first data set contains winter and annual radon concentration obtained during the National survey in 2010 and the second, contains only the radon concentration measured during the winter of 2013. Both data sets pertain to radon concentration from the same cities and have been measured applying the same methodology in ground floor dwellings. The results appeared to be consistent and the dispersion of radon concentration was low. Linear regression analysis of the radon concentration measured in winter of 2010 and of the 2010 annual radon concentration revealed a high coefficient of determination R-2 = 0.92, with a relative uncertainty of 3%. Furthermore, this model was used to estimate the annual radon concentration solely from winter-term measurements performed in 2013. The geometrical mean of the estimated annual radon concentration of the 2013: radon concentration (A-2013) =98 Bqm(-3) was almost equal to the geometrical mean of the annual radon concentration from the 2010, radon concentration (A-2010) = 99 Bqm(-3). Analysis of the influence of building characteristics, such as presence/absence of a basement in the building, or the dominant building material on the estimated annual radon concentration is also reported. Our results show that a low number of relatively short-term radon measurements may produce a reasonable insight into a gross average obtained in a larger survey

Uspostavljanje popisa morskih invazivnih vrsta u ESENIAS području: sadašnja situacija i buduća očekivanja

In this study we present a list of invasive/potential invasive alien species in the East and South European Network for Invasive Alien Species (ESENIAS) countries with marine borders. The species were classified according to the existing literature and experts’ judgment, as established, casual, invasive and expected. Finally, factsheets were compiled for ten species of high importance based on their expanding/invading character. Of the 160 species comprising the list, 149 were already present in the ESENIAS countries, while eleven were invasive species either present in the Mediterranean or in other European Seas, likely to be recorded in the ESENIAS countries. The majority of the species were of Red Sea/IndoPacific origin (97 species; 60.6%). Italy, Turkey and Greece were the countries with the highest representation of species (159, 152 and 139 species respectively), due to their extended coastline and the number of scholars working on marine invasive species. The highest number of established species was recorded in Turkey (116 species), whereas in Italy and Greece the most numerous species were the “expected” ones (85 and 48 species, respectively). The eastern Adriatic Sea countries (i.e. Albania, Croatia, Montenegro and Slovenia) had generally low numbers of species in this list, many of which are still “expected” to arrive from the neighbouring countries of Greece and Italy. Finally, the most frequently potential pathway was transfer stowaways (ship ballast water: 41 cases; ship hull fouling: 55), whereas unaided spread of Lessepsian immigrants followed (95 cases). This list is intended to serve as an early warning system that through horizon scanning process would assist ESENIAS countries to prioritise invasive alien species, their pathways and the areas of higher likelihood to appear, in order to take management measures.U ovom radu predstavljamo popis invazivnih i potencijalno invazivnih vrsta na istoku i jugu Europske mreže za invazivne vrste (ESENIAS) u zemljama s morskim granicama. Vrste su klasificirane prema postojećoj literaturi i procjeni stručnjaka, pa su tako utvrđene grupe povremenih, invazivnih i očekivanih vrsta. Podaci su dati za deset vrsta čija se važnost temelji na njihovom širenju i invazivnom karakteru. Od 160 vrsta koje sadrži popis, 148 je već bilo prisutno u ESENIAS zemljama, dok je 9 invazivnih vrsta bilo prisutno u Sredozemnom ili u drugim europskim morima, a vjerojatno je da će se zabilježiti i u zemljama udruženim u ESENIAS. Većina vrsta je bile iz Crvenog mora / indopacifičkog podrijetla (97 vrsta, 60,6%). Italija, Turska i Grčka su zemlje s najvišom zastupljenošću vrsta (159, 152 i 139), zbog njihove proširene obale i broja znanstvenika koji rade na morskim invazivnim vrstama. Najveći broj utvrđenih vrsta zabilježen je u Turskoj (116 vrsta), dok su u Italiji i Grčkoj najbrojnije vrste bile “očekivane” (85 i 48 vrsta, respektivno). Istočne zemlje Jadranskog mora (npr. Albanija, Hrvatska, Crna Gora i Slovenija) imale su općenito nizak broj vrsta na ovom popisu, od kojih mnoge još “očekujemo” da pristignu iz susjednih zemalja: Grčke i Italije. Konačno, najčešće su potencijalni putovi bili „transferni putnici“ (balastna voda broda: 41 slučaj, obraštaj brodskog trupa: 55), dok je slijedilo i širenje lesepsijskih migranata (95 slučajeva). Ovaj popis je namijenjen da služi kao sustav ranog upozorenja koji bi kroz proces skeniranja pomogao državama ESENIAS da daju prioritet invazivnim stranim vrstama, njihovim putovima i područjima veće vjerojatnosti pojavljivanja, kako bi se poduzele potrebne mjere upravljanja

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