Radon levels and indoor air quality after application of thermal retrofit measures-a case study.

This study was conducted to evaluate the influence of thermal retrofit on radon levels in workrooms, and to determine whether the radon concentration in the building changes after the application of retrofit measures. In the first survey, digital Airthings Corentium Home radon detector was used for 1-month radon measurements during the heating season 2018/19. The daily averaged radon concentrations varied from 37 to 573 Bq/m3 for 10 selected workrooms, while hourly averaged radon measurements showed extreme variations from 6 to 1603 Bq/m3 due to radon fluctuations. In second survey, passive radon technique based on charcoal canister test kit was conducted in all basement workrooms in spring 2021. The averaged radon concentrations grouped according to flooring type in workrooms were 327 Bq/m3 for parquet, 227 Bq/m3 for ceramic tiles, 146 Bq/m3 for vinyl flooring and 71 Bq/m3 for laminate. Besides thermal insulation and airtight windows, noticeable differences in indoor radon concentration within the renovated building are primarily caused by different types of flooring. It includes various types of insulation from the ground/concrete slab: laminate, parquet (wood blocks), vinyl flooring, and ceramic tiles. Detailed analysis point out that laminate is more efficient way for radon protection than other types of flooring. An efficient ventilation system should be installed to avoid increasing occupational radon exposure and to provide healthy and comfortable indoor environment.

Identification of high radon dwellings, risk of exposure, and geogenic potential in the mining area of the "TREPCA" complex.

This study was performed to investigate radon levels in dwellings in the mining area near the town of Kosovska Mitrovica. The Passive radon technique based on the charcoal canister test kit conducted in summer and autumn 2019 showed unexpected results. The reference level of 300 Bq/m3 for indoor radon concentration was exceeded in 15 of 26 dwellings. Preliminary measurements of gamma dose rate in some dwellings built from local stone showed values from 0.30 to 0.45 µSv/h, while 75% of measurements in dwellings with stone foundations had radon above the reference level. The highest radon concentration (22 500 ± 220 Bq/m3 ) was measured in the cellar of one family house. The RAD7 device (Durridge Company, Inc.) was used to measure radon concentrations in water and nearby soil of some dwellings. Indoor radon concentration fluctuated significantly over two days; over a one-day time scale, radon varied from 2843 ± 217 Bq/m3 at midnight to 1449 ± 104 Bq/m3 in the morning at one site, and abruptly decreased from a maximum of 2146 ± 262 Bq/m3 in one day to a minimum of 21 Bq/m3 the next day at another site. The influence of geological substrate on radon exposure was discussed through the estimation of geogenic radon potential, which varies from low the high radon index despite to high permeability of soil.

Plant uptake and soil retention of radionuclides and metals in vineyard environments.

In most European countries, each adult citizen drinks on average more than 20 L of wine every year. Three popular wine-growing areas (Aleksandrovac, Topola, and Orahovac) in Serbia were studied in order to investigate the abundance and uptake of elements from vineyard soil to plants. The specific activities of radionuclides (226Ra, 232Th, 40K, 137Cs, and 7Be) were measured in soil, leaves, and grape berries. 226Ra and 232Th were positively correlated with silt and clay and negatively correlated with sand content in soil. Specific activities of natural radionuclides were also negatively correlated with soil pH and CaCO3. Significant correlations of 40K and 137Cs with organic matter in soil were found. Concentrations of fifteen metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, Fe, K, Na, Ca, Mg, and Hg) were also measured in soil samples as well as in grapevine leaves. Analyzed soils were rich in Ni, Cu, Co, Cr, and Cd. High concentrations of Cu were probably caused by long-term use of Cu-based fungicides. Cu was correlated with Fe and organic matter content in soil. Soil-to-plant transfer factors (TF) were calculated to estimate the uptake of radionuclides and metals. Correlations obtained via PCA enable distinction between the sites Aleksandrovac and Topola relative to Orahovac. The first principal component (PC1) accounting for 30.70% of the total variance correlated significantly with soil pH (H2O), contents of CaCO3, Na, Ca, 40K, and 226Ra in soil, as well as with 226Ra, Na, Ca in plants and TFCa. The second principal component (PC2), with total variance of 17.21%, was mainly correlated with variables pertaining to Mg, Co, and Cr in the soil and TFK.

Spa environments in central Serbia: Geothermal potential, radioactivity, heavy metals and PAHs.

This study aims to estimate geothermal potential, radioactivity levels, and environmental pollution of six most popular spas in Central Serbia (Ovcar, Gornja Trepca, Vrnjacka, Mataruska, Bogutovacka and Sokobanja), as well as to evaluate potential exposure and health risks for living and visiting population. Thermal possibilities of the studied spas showed medium and low geothermal potential with total thermal power of 0.025 MW. Gamma dose rates in air varied from 63 to 178 nSv h-1. Specific activities of natural radionuclides (226Ra, 232Th and 40K) and 137Cs in soil were measured; annual effective doses and excess lifetime cancer risk from radionuclides were calculated. Radon concentration in thermal-mineral waters from the spas ranged between 1.5 and 60.7 Bq L-1 (the highest values were measured in Sokobanja). The annual effective dose from radon due to water ingestion was calculated. The analyzed soils had a clay loam texture. The presence of As, Cr, Cu, Fe, Mn, Ni, Pb, Cd, Zn, and Hg in soil was investigated. The concentrations of As, Cr, Ni, and Hg exceeded the regulatory limits in many samples. Soil samples from Mataruska spa were generally the most contaminated with heavy metals, while the lowest heavy metal concentrations were observed in Sokobanja. Health effects of exposure to heavy metals in soil were estimated by non-carcinogenic risk and carcinogenic risk assessment. Total carcinogenic risk ranged between 6 × 10-4 and 137 × 10-4 for children and between 0.1 × 10-4 and 2.2 × 10-4 for adults. The sum of 16 PAHs analyzed in soil samples varied from 92 to 854 µg kg-1.

EFFECTIVE DOSES ESTIMATED FROM THE RESULTS OF DIRECT RADON AND THORON PROGENY SENSORS (DRPS/DTPS), EXPOSED IN SELECTED REGIONS OF BALKANS.

The main contribution to population exposure is due to radon and thoron progenies and not radon itself. The aim of this study was therefore to estimate annual effective dose using the results of Direct Radon and Thoron Progeny Sensors were exposed in 69 selected schools and 319 dwellings in several regions of Balkans: in Serbia: regions of Sokobanja and Kosovo and Metohija, Republic of Macedonia, Republic of Srpska and Slovenia. Obtained average total effective doses are in the range from 0.22 mSv a-1 (schools in Republic of Srpska) to 2.5 mSv a-1 (dwellings in Kosovo) and are below the reference level of 10 mSv a-1 recommended by International Commission on Radiological Protection.

Environmental risk assessment of radioactivity and heavy metals in soil of Toplica region, South Serbia.

Activity levels of natural and artificial radionuclides and content of ten heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and Hg) were investigated in 41 soil samples collected from Toplica region located in the south part of Serbia. Radioactivity was determined by gamma spectrometry using HPGe detector. The obtained mean activity concentrations ± standard deviations of radionuclides 226Ra, 232Th, 40K and 137Cs were 29.9 ± 9.4, 36.6 ± 11.5, 492 ± 181 and 13.4 ± 18.7 Bq kg-1, respectively. According to Shapiro-Wilk normality test, activity concentrations of 226Ra and 232Th were consistent with normal distribution. External exposure from radioactivity was estimated through dose and radiation risk assessments. Concentrations of heavy metals were measured by using ICP-OES, and their health risks were then determined. Enrichment by heavy metals and pollution level in soils were evaluated using the enrichment factor, the geoaccumulation index (Igeo), pollution index and pollution load index. Based on GIS approach, the spatial distribution maps of radionuclides and heavy metal contents were made. Spearman correlation coefficient was used for correlation analysis between radionuclide activity concentrations and heavy metal contents.

Is high indoor radon concentration correlated with specific activity of radium in nearby soil? A study in Kosovo and Metohija.

This paper presents indoor radon concentrations and specific activities of natural radionuclides measured in soils of Kosovo and Metohija. The measurements of radon concentration were performed during two consecutive 6-month periods in two rooms of 63 houses using CR-39 detectors. The annual radon concentration ranged from 30 to 810 Bq m-3 with the average value of 128 Bq m-3. Almost 15% of the houses had radon concentration higher than 200 Bq m-3. The difference between radon concentrations measured in the two 6-month periods was analyzed, showing, as expected, a slightly higher radon concentration in the "winter period" than in the "summer period". The variation between different rooms of the same houses was also analyzed, showing that 20% of the dwellings had a significantly higher radon concentration (>100 Bq m-3) in one room compared to the other (the coefficient of variation ranged up to 96%). The specific activities of natural radionuclides in the nearby soil were determined by gamma spectrometry. The estimated average value (and standard deviation) of 226Ra, 232Th, and 40K specific activities were 32 (13), 35 (16), and 582 (159) Bq kg-1, respectively. The correlation between indoor 222Rn and 226Ra content in soil was investigated. Only a weak correlation was found (Spearman's rho = 0.220) indicating that other factors might affect diffusion and accumulation of radon indoors, as confirmed also by the high variability between the rooms of the same houses.

Persistent organic pollutants, heavy metals and radioactivity in the urban soil of Pristina City, Kosovo and Metohija.

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), heavy metals content and radioactivity levels were measured in 27 soil samples collected from Pristina, the capital of Kosovo and Metohija. The sixteen PAHs, twelve OCPs and six PCBs congeners were determined by gas chromatography system with mass spectrometry detection. Although the use of PCBs and OCPs was prohibited decades ago residues of those compounds still existed in measurable concentrations in soils of Pristina. PAHs were also present in analyzed samples but their mean concentration was significantly lower than mean concentrations of PAHs previously reported in urban areas in the world. The concentrations of heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) were determined by the EDTA extraction protocols, along with their extractable concentrations. The activity concentrations of natural radionuclides (226Ra, 232Th and 40K) were determined by gamma spectrometry method. The Shapiro-Wilk normality test found that activity concentrations of natural radionuclides were normally distributed. Radiological risk was estimated through the annual effective dose, gonadal dose equivalent, excess lifetime cancer risk, radium equivalent activity, external and internal hazard indexes. Spearman correlation coefficient was used for analysis of correlations between physicochemical properties, heavy metal contents and radionuclide activity concentrations. Strong positive correlation between 226Ra and 232Th was found, as well as among pairs of As-Cd and Co-Mn. Very strong positive correlation (0.838) at the 0.01 significance level was noted for Pb-Zn pair. Strong correlations indicate common occurrence of these elements in the nature, as well as geogenic association.

Indoor radon and thoron concentrations in some towns of central and South Serbia.

This study presents the results of indoor radon and thoron activity concentrations of some municipalities in central and south part of Serbia: Krusevac, Brus, Blace and Kursumlija. Measurements were carried out in 60 dwellings during the winter season. Passive discriminative radon-thoron detectors known as UFO detectors were used. The mean values of indoor radon and thoron concentrations were 82 Bq m-3 and 42 Bq m-3, respectively. Population-weighted mean values were 76 Bq m-3 and 40 Bq m-3, respectively. 26.7% of dwellings had radon concentration higher than 100 Bq m-3 (one location had even more than 300 Bq m-3). There are no statistically significant correlations of indoor radon and thoron concentrations neither with the period of house construction, nor with the existence of a basement. The results of this study represent the first step of investigating radon and thoron levels in these parts of Serbia and therefore could be the basis for creating a radon map.

First step of indoor thoron mapping of Kosovo and Metohija.

The survey of natural radioactivity in Kosovo and Metohija involves 180 indoor (220)Rn measurements. They were performed either in living rooms or in bedrooms of 127 individual, rural type houses, using a passive method with application of CR-39 solid-state nuclear track detectors. Detectors were deployed at a distance of >10 cm from the walls. Values of all 180 measurements for 127 houses give an arithmetic mean (AM) of 132 Bq m(-3). The data for indoor thoron mapping arranged within 10 km × 10 km grid cells give an AM of 118 Bq m(-3) over AM grid cells. The distribution over individual data and the grid cells can be described as normal. About 19 % of the area of Kosovo and Metohija was covered by mapping. This study includes statistical analysis and discussion of factors, such as geogenic and seasonal, which possibly affect thoron concentration, as well as comparison with simultaneous radon measurements.

Correlation between radioactivity levels and heavy metal content in the soils of the North Kosovska Mitrovica environment.

This paper reports the results of radioactivity concentrations and heavy metal content in soil samples collected from non-agricultural areas in the municipality and vicinity of North Kosovska Mitrovica, formerly the most important mining area in Europe. The estimated average activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs are 40.6 ± 19, 48 ± 25.4, 743.2 ± 200.5 and 81 ± 119 Bq kg(-1), respectively. The estimated average absorbed dose rate in the air and the annual effective dose are 78.7 nGy h(-1) and 96.6 µSv, respectively. The radium equivalent activity and external hazard index were also calculated. High contents of Pb, Zn, Cu, Cd, As and Ni were found in the analyzed soil samples, thus indicating pollution of the environment. Most metals have a wide range of values spanning 2 to 3 orders of magnitude, which is particularly evident for Pb and Zn. Correlations between the activity concentrations of the radionuclides, the heavy metal content in soil and the basic soil properties were determined by means of the Pearson linear coefficient. Strong positive correlations between the naturally occurring radionuclides, and also among Pb, Zn, Cu and Cd were found.