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After year-long measurements with CR-39 detectors, nationwide radon survey was performed in 953 homes – 0.5 % of all permanently inhabited dwellings in Montenegro. Influence of 11 factors (area, climate, type of house, year of construction, basement, foundation slab, number of stories, building materials, window frames, heating, and smoking) and 35 their 35 categories on the radon concentrations in 732 ground-floor dwellings was analyzed using descriptive, univariate and multivariate methods. Univariate analysis dropped influence of the two factors: heating and smoking. It reveals that, on average, radon concentrations in ground-floor dwellings differ at 95 % confidence level in urban and rural areas, in family houses and apartment buildings, in houses with and without basement, and in dwellings with window frames made of wood and PVC/Al. In Cf climate zone they differ from those in Cs and Df zones. Only two pairs of construction periods differ in mean radon concentrations in dwellings: 1980-1999 with 1900-1944, and with 1964-1979. Houses with one, two or three stories have almost equal average radon levels, which are higher than in buildings with more than three stories. Mean value of radon concentrations in houses made of stone are higher than in houses made of concrete, or bricks, or wood. Multivariate analysis revealed that six of the analyzed factors: area, climate, type of house, presence of basement, number of stories, and building materials simultaneously have significant relationships (p < 0.05) with radon concentrations in dwellings on ground floor in Montenegro.

A national radon survey was performed recently in all buildings of pre-university education in Montenegro. During the school year 2016/2017, radon (222Rn) was measured with passive detectors (Radosys, RSFV type) in 2855 ground-floor rooms of 468 buildings. The average 9-month radon activity concentrations above the level of 300 Bq/m3 were found in 728 rooms, which belong to 213 buildings, while in 111 rooms, belonging to 47 buildings, they were above 1000 Bq/m3. Radon concentrations in the educational buildings, averaged over all sampled ground-floor rooms in a building, range from 16 Bq/m3 to 2810 Bq/m3, with arithmetic mean (AM) = 275 Bq/m3. They follow a log-normal distribution with geometric mean (GM) = 174 Bq/m3 and geometric standard deviation (GSD) = 2.58. There are 135 buildings with average indoor radon concentrations on the ground floor above 300 Bq/m3 and 18 buildings where they are above 1000 Bq/m3. The influence of the nine factors (climate, urban/rural area, age of building, number of stories, building materials, basement, foundation slab, window frames, and heating) on radon concentrations in the buildings was analysed by univariate (UVA) and multivariate (MVA) methods. The univariate analysis revealed the significant relationship of the four factors: age of buildings, basement, building materials, and window frames with radon concentrations on the ground floor in the buildings, while multivariate analysis added to those factors urban/rural area and number of stories, but excluded building materials as a factor influencing significantly radon concentrations.

Change of radon concentrations in dwellings with floor level was studied in six multi-story buildings, in four towns of Montenegro with different climate conditions. The annual aver- age radon activity concentrations in 35 dwellings are found to be very low, mostly at a level of 20-30 Bqm–3. Absorbed gamma dose rates in these dwellings are in the range of 14-58 nGyh–1. The low radon concentrations are a consequence of a good tightness of the structures in contact with the ground and a small contribution of building materials to radon indoors. A clear general trend of changes in radon concentrations with floor level is not observed. In most of the dwellings on different floors in the multi-story building radon concentration varies very little, mostly within measurement error. A small decrease in radon concentration is noted between the two or three floors closest to the ground, but only in some of the buildings. Therefore, a decrease of indoor radon concentration with floor level cannot be considered as a general characteristic of multi-story buildings. Although the seasonal radon variations have not been in the focus of this study, it was found that the average radon activity concentrations in dwellings of the multi-story buildings are higher in warmer than in cooler half-year period, what is contrary to the general rule for homes in the world and in Montenegro as well.

Indoor radon was systematically surveyed in the town of Niksic—the second largest town in Montenegro—which has some of its settlements built above red bauxite deposits. The radon concentrations were measured in 55 homes in 2002/03, in the summer and winter period, using CR-39 etched track detectors. The average annual radon concentrations were. found to be lognormally distributed (geometric mean = 66.2 Bq m-3, geometric standard deviation = 3.0) within the range from 10 to 966 Bq m-3, with arithmetic mean of 122.7 Bq m-3 and median of 61.7 Bq m-3. Although the annual mean radon concentrations above the action level of 400 Bq m-3 are found only in four dwellings, the indoor radon levels in the town of Niksic are relatively high when compared with the average in the South European countries, as well as with indoor radon levels in other regions in Montenegro. [ABSTRACT FROM AUTHOR]

In the action of NATO A-10 airplanes in 1999, the cape Arza, Serbia and Montenegro was contaminated by depleted uranium. The clean-up operations were undertaken at the site, and 242 uranium projectiles and their 49 larger fragments were removed from the cape. That is about 85% of the total number of projectiles by which Arza was contaminated. Here are described details of the applied procedures and results of the soil radioactivity measurements after decontamination.

Recent residential radon survey in Montenegro revealed the national average annual radon activity concentrations: unweighted AM = 110 Bq m-3, GM = 58.3 Bq m-3, and population weighted (AM)w = 100.5 Bq m-3, (GM)w = 92.8 Bq m-3. Based on (AM)w and dose conversion factor of 9 nSv per Bq h m-3, average effective dose from exposure to indoor radon at homes is estimated to be 1.58 mSv y-1. 222Rn was measured with CR-39 detectors for two consecutive six-month periods. Radon concentrations are discussed with respect to their distribution, to the seasons, climate zones, urban and rural areas, house types, floor levels, basement and foundation slab. Average radon concentrations are calculated for each municipality and for cells of a 10 km × 10 km grid, and corresponding radon maps of Montenegro are then produced., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The first nationwide indoor radon survey in Montenegro started in 2002 and year-long radon measurements with CR-39 track-etch detectors, within the national grid of 5 km × 5 km and local grids in urban areas of 0.5 km × 0.5 km, were performed in homes in half of the country's territory. The survey continued in 2014 and measurements in the rest of the country were completed at the end of 2015. The 953 valid results, obtained in the national radon survey, give an average radon activity concentration in Montenegrin homes of 110 Bq/m 3 . Assuming a log-normal distribution of the experimental results, geometric mean GM = 58.3 Bq/m 3 and geometric standard deviation GSD = 2.91 are calculated. However, normality tests show that the experimental data are not log-normal, and that they become closest to a log-normal distribution after subtracting from them radon concentration in the outdoor air of 7 Bq/m 3 , which is theoretically calculated. Such a transformed distribution has GM tr  = 46.7 Bq/m 3 and GSD tr  = 3.54. The estimations derived from positing a priory that the experimental results conform to a log-normal distribution underestimate the percentage of homes with radon concentrations at the thresholds of 300 Bq/m 3 and above, which is better estimated by using GM tr and GSD tr . Based on the results of radon survey, a new national radon reference level of 300 Bq/m 3 and an "urgent action level" of 1000 Bq/m 3 are suggested, with estimated fractions of the national dwelling stock above these levels of 7.4% and 0.8% respectively. Fractions of homes with radon concentrations above the suggested levels are also estimated for each of the 23 municipalities in Montenegro, using appropriate GM tr and GSD tr . The six municipalities which have more than 10% of homes with radon concentration above 300 Bq/m 3 are recommended as radon priority areas., (Copyright © 2018 Elsevier Ltd. All rights reserved.)