High Natural Background Radiation Area Research Articles

Uranium Isotope Characterization in Volcanic Deposits in a High Natural Background Radiation Area, Mamuju, Indonesia

Mamuju is an area of high natural radiation in Indonesia with high natural radiation levels (average 613 nSv h−1). Mamuju is anomalous due to its high average 238U and 232Th concentrations of 22,882 and 33,549 Bq kg−1, respectively, in laterite and rock. High natural radionuclide concentrations of 238U, 232Th, and 40K have also been reported in soil samples from several locations in Mamuju, including Botteng, Northern Botteng, Takandeang, Ahu, and Taan. High radiation levels are related to radioactive mineral occurrences in the Adang volcanic complex, comprised of phonolitoid and foiditoid lithologies. According to the International Atomic Energy Agency (IAEA), uranium deposits can be classified into several types, among them a volcanic-related deposits, which include three sub-types: stratabound, structure-bound, and volcano-sedimentary deposits. This study aims to characterize volcanic rock deposit sub-types in the Mamuju area based on uranium radioisotope measurements. The uranium isotopes were measured using a tandem quadrupole inductively coupled plasma mass spectrometer combined with chemical separation by extraction chromatography using UTEVA resin. The analytical results for the 234U/238U ratios are used to determine the formation characteristics of minerals in each deposit sub-type based on mineral formation age, post-formation processes, and disturbances that affected the formation processes. Based on geochronological calculations using 234U/238U mineralization age, the deposits in the Mamuju area are 0.914–1.11 million years old and are classified as recent mineralization. These data have important implications for tracing uranium source rocks in the Mamuju area and may explain the anomalously high radiation levels in the Mamuju area.

Dosimetric Study on Natural Background Ionizing Radiation and Impact Assessment on Public Health: A systematic Review in Nigeria

Environmental natural background ionizing radiation contamination and degradation is a global concern because of its negative effect on public health. Public health risk continues to be one of the environmental and public concerns in Nigeria. The emission of natural background ionizing radiation from the outer space, crust of the earth, food, and water and construction materials contributed a lot to the public environmental exposure. The populations’ exposure to background radiation emanated from terrestrial, cosmic, and internal radiation account for 82% which are out of control. Present work was aimed to carry out an investigational study of the natural background ionizing radiation levels, identify locations with high or low BIR and assess the health effect within Nigeria’s communities based on the available data extracted from the literatures and establish a baseline data of exposure rate, absorbed dose rate, annual effective dose equivalent, and excess life cancer risk from outdoor and indoor background radiation. This dosimetric study of natural background radiation in Nigeria is important to monitor the levels of radiation to which people are exposed directly or indirectly. Recently, several studies have been done in Nigeria and different values were reported based on indoor and outdoor background radiation doses. In this paper, a review and literature survey of natural background ionizing radiation was carried out. The data extracted based on indoor and outdoor revealed that Plateau, Oyo, River, Delta and Ondo, Sokoto, Kano and Niger have the highest value of dose rate compared to the world average value. The order of magnitude of the dose rate were Plateau > Oyo > Rive > Delta > Ondo and River > Plateau > Sokoto > Kano > Oyo > Ondo > Delta > Niger for Indoor and outdoor respectively. The highest outdoor & indoor annual effective doses were observed in OYO, Sokoto, Ondo, Delta, Akwanga, Plateau, and River. The results were comparatively greater than the world acceptable limit of 1.0 mSv/y. The order of magnitude of annual effective are OYO > Sokoto > Ondo > Niger Delta and Akwanga > Plateau > Delta > River for outdoor and indoor respectively. The regions with highest excess life cancer risks in Nigeria were observed in Oyo, Akwanga, Ondo, Plateau, River, Kaduna, Anambra, Port court, Abuja, Delta, Ibadan and Kano. Radiation cancer induction values obtained were remarkably high compared to world average value of 0.29×10-3. The amount of radiation absorbed by individual organs exposed to high natural background radiation areas were observed to be highest in tests organ, the order of magnitude were Tests > Bone marrow > Whole body > Lung > Ovaries > Kidney > Liver. But all the estimated mean values of organs doses were remarkably lower than that of world average value. Since the mean absorbed dose rate and annual effective dose in several areas is higher than 0.084µSv/h and 1.0 mSv/year for general public in many locations, long term exposure of the public to these radiations may lead to radiation induced health hazard such as erythema, skin cancer, genetic mutation and sterility.

Assessment of Threshold Dose of Thoron Inhalation and Its Biological Effects by Mimicking the Radiation Doses in Monazite Placer Deposits Corresponding to the Normal, Medium and Very High Natural Background Radiation Areas.

The dose contributed from thoron (220Rn) and its progeny has been neglected in the dose assessment because of its short half-life (t1/2 = 55.6s) and generally low concentrations. Recently, concentrations of 220Rn gas and its progeny were found to be pronounced in the traditional residential dwellings in China, on beaches of India and in other countries. Accordingly, we investigated the biological effects of thoron (220Rn) decay products in various mouse organs, succeeding inhalation of thoron gas in BALB/c mouse. We investigated the biological effects upon thoron inhalation on mouse organs with a focus on oxidative stress. These mice were divided into (4 random groups): sham inhalation, thoron inhalation for 1, 4 and 10days. Various tissues (lung, liver and kidney) were then collected after the time points and subjected to various biochemical analyses. Immediately after inhalation, mouse tissues were excised for gamma spectrometry and 72h post inhalation for biochemical assays. The gamma spectrometry counts and its subsequent calculation of the equivalent dose showed varied distribution in the lung, liver and kidney. Our results suggest that acute thoron inhalation showed a differential effect on the antioxidant function and exerted pathophysiological alterations via oxidative stress in organs at a higher dose. These findings suggested that thoron inhalation could alter the redox state in organs; however, its characteristics were dependent on the total redox system of the organs as well as the thoron concentration and inhalation time.

Path Analysis : Public Health Impacts Overview in High Natural Background Radiation Area in Botteng, West Sulawesi of Indonesia

Introduction: The effect of ionizing radiation exposure in a human being is chromosome aberrations. Botteng has the highest annual radiation exposure rate in Indonesia, which is 6,15 ± 0,81 mSv/year. The people in Botteng were exposed to the low dose radiation, continuously. The purpose of this research is to describe the pathway radiation exposured to inhabitants and the cytogenetic response in the high natural background radiation area.Methods : This is a statistical research by cross-sectional. The population is 61 residents, who were chosen randomly from 9 different exposure rate areas. Path analysis model is used to determine the linearity relationship between internal and external radiation dose to the frequency of chromosomal aberrations in lymphocyte cells.Results: The results concluded that the external radiation dose rate is 5.49 mSv / year, the internal radiation dose rate is 10.34 mSv / year, the effective dose rate of lymphocyte cells is 1.92 mSv / year, and the mean of chromosome aberrations frequency is 0.00082 of approximately 14,695 metaphase cells observed. The result of the analysis showed that there was no significant correlation between the external dose and the chromosome aberrations frequency. There is a linear relationship between the internal dose and the chromosome aberrations frequency (f count = 6,634 and p-value 0,013 <0,05). The internal and external radiation dose simultaneously affects the effective dose (R2 = 0.901, p-value = 0,000> 0.05), The Internal and external radiation doses affect the chromosome aberrations frequency of peripheral blood lymphocytes only through effective doses (R2 = 0.093, p-value = 0.017> 0.05)Conclusion: this study provide an effective recommendation for further research as an effort to improve public health in areas with high natural background radiation.

Heavy Metal Assessments of Soil Samples from a High Natural Background Radiation Area, Indonesia.

Mamuju, Indonesia, is an area with high natural background radiation. This study assesses heavy metal content in soil samples from this area to determine the level of public and environmental hazard it presents. This study analyzes natural radionuclide elements using high purity germanium (HPGe) gamma spectrometry and performs heavy metals analysis using a flame atomic absorption spectrometry (FAAS). Moreover, pollution indices and descriptive analyses were used to assess heavy metal contamination in the environment and the correlation between heavy metals and radionuclides. The results demonstrate that soil samples in several areas of Mamuju contain a high concentration of the natural radionuclides 226Ra and 232Th, and that heavy metal concentrations in the soil decrease in the sequence Zn > Pb > Cr > Cu > Ni > Cd. This study revealed that soil samples from Mamuju are moderately contaminated. There was a strong positive relationship between 226Ra, 232Th, ambient dose equivalent rate, and Pb. Ecological risk index (RI) and cumulative pollution index (IPI) values in Mamuju are 2.05 and 125, respectively, which are possible hazards to human health as a result. Pb concentration in the Mamuju soil samples ranged from 109 to 744 mg kg−1, exceeding the worldwide average of 27 mg kg−1.

A unique high natural background radiation area in Indonesia: a brief review from the viewpoint of dose assessments

A unique high natural background radiation area in Indonesia: a brief review from the viewpoint of dose assessments

Comprehensive exposure assessments from the viewpoint of health in a unique high natural background radiation area, Mamuju, Indonesia

Mamuju is one of the regions in Indonesia which retains natural conditions but has relatively high exposure to natural radiation. The goals of the present study were to characterize exposure of the entire Mamuju region as a high natural background radiation area (HNBRA) and to assess the existing exposure as a means for radiation protection of the public and the environment. A cross-sectional study method was used with cluster sampling areas by measuring all parameters that contribute to external and internal radiation exposures. It was determined that Mamuju was a unique HNBRA with the annual effective dose between 17 and 115 mSv, with an average of 32 mSv. The lifetime cumulative dose calculation suggested that Mamuju residents could receive as much as 2.2 Sv on average which is much higher than the average dose of atomic bomb survivors for which risks of cancer and non-cancer diseases are demonstrated. The study results are new scientific data allowing better understanding of health effects related to chronic low-dose-rate radiation exposure and they can be used as the main input in a future epidemiology study.

Assessment of a naturally occurring high background radiation area with elevated levels of thorium along coastal Odisha, India using radiometric methods

The present study evaluates the enrichment and distribution of radioelements along the eastern coast of India. India possesses the second largest reserve of thorium bearing monazite in the world, in terms of heavy minerals present primarily along its long coastline. Radioelement estimation of about 30 km long beach area along the eastern coast of India is reported and implications discussed. A total number of 822 data points were studied using a portable Geiger Muller counter, to estimate the variation of dose rates, due to the ambient radionuclides along two different trends. One was parallel (northeast-southwest) and the second one perpendicular to the coastline. Pre-selected samples from in-situ radiometric surveys on the heavy mineral placers were studied further, for quantitative estimation of the abundance of radioactive elements primarily uranium and thorium, using a High Purity Germanium detector. Radioelement concentration assessment of core samples (depth ~2 m), were studied from two different beaches. Radiological parameters like radium equivalent, annual effective doserate and absorbed dose rate has been calculated based on the 238U, 232Th and 40K concentrations. Heavy mineral placers along the shoreline indicate a very high thorium (avg - 2990.22 Bq kg−1) which is due to the extensive distribution indicative of monazite. The coastal area also exhibits relatively low uranium (avg - 319.1 Bq kg−1). Based on its high thorium concentration, the area can be considered as a high natural background radiation area. Based on the concentrations of uranium and thorium, the weathering conditions and depositional environment prevalent along the beach areas have been discussed.

К вопросу о формировании адаптивного ответа под действием природного и профессионального факторов хронического облучения. Обзор литературы

The paper summarizes results of medical examination of two groups of patients, the public members resided in high natural background radiation areas and occupationally irradiated nu-clear and health workers. Adaptive response to chronic exposure to radiation was found to last much time and, thus, its impact on the development of late health effects, including cancer, may be great. In vitro studies demonstrate that induction of adaptive response is the multistep process including the excision reparation of nucleotides, nonhomologous DNA ends joining, antioxidative system and cell cycle control factors. The review presents data on effects of low doses radiation of high or low relative radiation effectiveness(RBE). Some damaged peripheral blood lympho-cytes demonstrated increased radioresistance to high radiation doses, results of examinations of both the public members and professionals.

Lens opacity prevalence among the residents in high natural background radiation area in Yangjiang, China.

The aim of the study was to evaluate the risk and threshold doses of lens opacity among residents exposed to low-dose radiation. Residents aged ≥45 years were recruited from a high natural background radiation (HNBR) area in Yangjiang City and a control area selected from nearby Enping City. Lens opacities (LOPs) were classified according to the Lens Opacities Classification System (LOCS) III system. Face-to-face interviews were conducted to collect information on lifestyles, migration and medical history. Life-time cumulative doses were estimated using gender, age, occupancy factors and environmental radiation doses received indoors and outdoors. Logistic regression analyses were conducted to estimate the dose response and determine thresholds. In the HNBR area, among 479 study participants, 101 (21.1%), 245(51.1%) and 23 cases (4.8%), respectively, of cortical, nuclear and posterior subcapsular (PSC) LOPs were found. In the control area, those types of LOPs were identified among 58 cases (12.6%), 206 cases (51.2%) and 6 cases (1.3%) of 462 examinees, respectively. Cumulative eye lens dose was estimated to be 189.5 ± 36.5 mGy in the HNBR area. Logistic analyses gave odds ratios at 100 mGy of 1.26 [95% confidence interval (CI) 1.00–1.60], 0.81 (95% CI 0.64–1.01) and 1.73 (95% CI 1.05–2.85) for cortical, nuclear and PSC LOPs, respectively. For cortical LOPs, a logistic analysis with a threshold dose gave a threshold estimate of 140 mGy (90% CI 110–160 mGy). The results indicated that population exposed to life-time, low-dose-rate environmental radiation was at an elevated risk of cortical and PSC LOPs. A statistically significant threshold dose was obtained for cortical LOPs and no threshold dose for PSC LOPs.

A unique high natural background radiation area – Dose assessment and perspectives

The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h−1 and 1109 nGy h−1. Indoor radon concentrations ranged from 124 Bq m−3 to 1015 Bq m−3. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m−3 recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.

Radiological impacts in the high-level natural radiation exposure area residents in the Ramsar, Iran

Radiological impacts due to external and internal exposure to high natural background radiation areas caused by the $${}^{226}\hbox {Ra}$$, $${}^{232} \hbox {Th}$$, and $${}^{40}\hbox {K}$$ in the soil of Ramsar, Iran, were carried out. Residual Radioactive Material Guidelines code was applied to the calculation of excess cancer risk of residence. This evaluation shows that the excess cancer risk value is the highest in 20 years’ and the lowest value in 120 years’ during the time. The results obtained from this research will be useful for risk assessment and decision making for public health protection against high-level radiation.

Radon Risks Assessment with the Covid-19 Lockdown Effects

This work draws attention to the effects of the second cause of lung cancer which is also the largest source of exposure to ionizing radiation, radon, during the lockdown recommended by the World Health Organization (WHO) due to the Covid-19 pandemic. The basic assumption is that the exposure times have been assimilated to the 03-month lockdown time and the 02-week maximum incubation period of the disease. Doses during these periods and Relative Risk of Lung Cancer (RRLC), Lung Cancer Cases per year per million people (LCC) and Excess Lifetime Risk of Cancer (ELRC), were evaluated based on the concentrations obtained in high natural background radiation area in Cameroon. The existing exposure situation due to radon is then reevaluated and ranged from 0.76% to 17.55%. These results show that the reconsidered exposure time would be equivalent to the exposure time of a worker over one year, with their respective doses values becoming equivalent. The risks of developing lung cancer were also evaluated and it has been found that due to this pandemic it unfortunately increased.

Ambient dose measurement from high natural background radiation (HNBR) in Botteng Utara Village, Mamuju-Indonesia

The terrestrial environment is one of the contributors to natural background radiation. Mamuju Regency, located in the Province of West Sulawesi Indonesia is known as the high natural background radiation (HNBR) area due to its high terrestrial exposure. Botteng Utara Village is one of the areas with dose rates up to 5 mSv/y in Mamuju district. For this reason, measurements were taken to determine the ambient dose received by society. In situ measurements were carried out in Botteng Utara Village using 70 OSL (Type EX-OSLD Environment) installed in 70 houses. The selection of houses is made with various types of building materials, randomly selected from 10 hamlets with each of 7 houses per sub-village. Measurements were done for ± two months from February 20, 2019 to April 12, 2019. The range of ambient dose achieved by measurement was from 51 up to 176 mRem/h. Further investigation using a larger sample number and longer time should be performed to validate this study’s results. This result will serve as a baseline for further research regarding the possibility of radiation effects on the society in Botteng Utara Village in Mamuju district.

Annual committed effective dosage from natural radionuclides by ingestion of local food growing in mineral mining area, Sri Lanka.

Sri Lanka's largest mineral sand deposit occurs in Pulmoddai, and the surrounding area of the mineral sand deposit has been identified as a high natural background radiation area. The food crops grown in the area are used for human consumption. However, the long-term consumption of high radioactive foodstuff may cause health defects. The objective of the present study was to assess the radiological impact on individuals due to ingestion of foodstuffs grown in Pulmoddai area. Seasonal food crops growing in the area, including cereals, vegetables, nuts, fruits and yams were collected and used to prepare common meal plans consumed by the residents. Samples were analyzed with high-purity germanium gamma spectrometer for activity concentrations. Activity concentration of 40K was observed in higher amounts in every food sample. Trace amounts of 137Cs 232Th and 7Be were also identified. The total committed effective dosage to an adult from gamma-emitting radionuclides from cooked meals was 0.1482mSvyear-1, and raw foodstuff was 0.0667mSvyear-1, which are far below than the harmful levels declared by International Atomic Energy Agency. Results concluded that foodstuff and cooked meals consumed by the people who live in Pulmoddai, Sri Lanka, are radiologically safe.

GAMMA DOSE RATES IN THE HIGH BACKGROUND RADIATION AREA OF MANGALORE REGION, INDIA.

Elevated levels of natural background radiation due to scattered patches of monazite sand around the beaches of Mangalore, India, have been reported earlier. A comparative study of gamma dose rates was performed in both normal background and high natural background radiation areas around Mangalore using different types of portable gamma dosimeters. In addition to this, gamma-ray energy spectra were acquired, in situ, using a NaI(Tl) based portable gamma spectrometer. Soil and sand samples were collected for laboratory analysis with HPGe detectors. Measurements were carried out during the years 2016-18 revealed that in majority of the locations the gamma dose rates were similar to the normal background regions, whereas, in certain locations the dose rates were higher with values up to 530 nSv/h.

Lymphocyte Proliferation Kinetics in Inhabitant of Takandeang Village, Mamuju: A High Background Radiation Areas in Indonesia

BACKGROUND: Mamuju area in West Sulawesi considered as the high natural background radiation area in Indonesia. Our previous study showed that the mean mitotic index (MI) and nuclear division index (NDI) in lymphocytes of Botteng Village, Mamuju inhabitants was lower compared to control samples. To validate our previous study results, here in this study the evaluation of cell proliferation markers which were MI and NDI in peripheral blood lymphocytes (PBL) of Takandeang Village inhabitants was conducted.METHODS: A total 60 people were enrolled in this study, consisted of 35 samples from Takandeang Sub-Village and 25 from normal background radiation area. MI was calculated manually and automatically using Metafer 3.11.2 imaging system. The NDI defined as proportion of mononucleated, binucleated, trinucleated and tetranucleated cells were conducted using cytokinesis block micronucleus (CBMN) assay.RESULTS: The results of this study showed that the mean manual MI in Takandeang Sub-Village inhabitants was lower compared to control group (4.96±2.25 vs. 5.93±2.14). In contrast, the mean automatic MI (20.37±10.49 vs. 18.87±7.49) and NDI (1.555±0.174 vs. 1.523±0.112) in Takandeang Sub-Village inhabitants was higher compared to the control group. Statistical analysis revealed that the difference of mean manual MI, automatic MI and NDI in Takandeang Sub-Village inhabitants was not significantly different compared to the control group(p>0.05).CONCLUSION: It can be concluded that based on this study the chronic low radiation dose exposure in Takandeang Sub-Village, Mamuju has no significant effect on the lymphocytes proliferation.KEYWORDS: lymphocytes, mitotic index, nuclear division index, high background radiation

Investigation of geological and soil influence on natural gamma radiation exposure and assessment of radiation hazards in Western Region, Peninsular Malaysia

This study was conducted to investigate the influence of geological and soil formation on natural gamma (γ) radiation exposure. The aim of this study also to obtain a baseline data of γ radiation exposure and radioactivity associated with soil in the granitic territory at Western Region of Peninsular Malaysia. From 3727 in situ measurements of γ radiation dose rates, the mean value of dose rate obtained in this study is 204 nGy h−1 with the range of between 17 and 1039 nGy h−1. The mean value obtained in this study is three times higher than the world average value of 57 nGy h−1. Based on in situ measurements, the range of annual effective dose received by the population living in the study area is 0.02–1.28 mSv y−1. The study found that the levels of γ radiation exposures are strongly influenced by the geological and soil types. From the gamma spectrometry analysis, the mean radioactivity levels of 226Ra, 232Th and 40K in soil in western region Peninsular Malaysia are slightly higher and comparable with the places of “High Natural Background Radiation Areas” (HNBRAs) in the world as reported by UNSCEAR (2000). The mean value of 226Ra was 120 Bq kg−1 and ranged from 7 to 554 Bq kg−1, whilst for 232Th was 276 Bq kg−1 with a range of 23–1806 Bq kg−1. These values indicate 3 and 9 times, respectively, higher than the world average values. However, the radium equivalent activity (Raeq) obtained in this study (277 Bq kg−1) is lower than permissible values of 370 Bq kg−1. The radiological indices of radiation hazards in this study show that the index values are higher than the permissible limit values of 1. The mean value for gamma activity index (I γ ,) external hazard index (H ex), internal hazard index (H in) was 1.89, 1.46 and 1.78, respectively. As well as γ radiation levels, radioactivity levels of 226Ra, 232Th and 40K also were strongly influenced by the geological and soil types.

A high natural radiation area in Khao-Than hot spring, Southern Thailand.

Natural radioactivity in Khao-Than hot spring area, Surat Thani Province, Thailand was investigated. Gamma dose survey indicated a possible high radiation risk for this area. Rock, soil and hot spring mud samples were collected and analysed by a low background gamma spectrometer. The activity concentrations of (226)Ra, (232)Th and (40)K in samples were 151-139 092 (mean = 13 794), 12-596 (127), 24-616 (215) Bq kg(-1), respectively. X-ray diffraction and Fourier transform infrared spectroscopy indicated that quartz and calcite (CaCO3) are the main constituents in mud samples with varying contents. In conclusion, this study area was reasonably classified as a high natural background radiation area. The source of radium in this area is supposed to be related to the fault fluids enriched in radium that precipitated with calcium in the carbonate terrain and partly absorbed by high cation exchange capacity clays.

Distribution of uranium, thorium and some stable trace and toxic elements in human hair and nails in Niška Banja Town, a high natural background radiation area of Serbia (Balkan Region, South-East Europe)

Human hair and nails can be considered as bio-indicators of the public exposure to certain natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their levels in other tissues of body. Niška Banja, a spa town located in southern Serbia, with locally high natural background radiation was selected for the study. To assess public exposure to the trace elements, hair and nail samples were collected and analyzed. The concentrations of uranium, thorium and some trace and toxic elements (Mn, Ni, Cu, Sr, Cd, and Cs) were determined using inductively coupled plasma mass spectrometry (ICP-MS). U and Th concentrations in hair varied from 0.0002 to 0.0771 μg/g and from 0.0002 to 0.0276 μg/g, respectively. The concentrations in nails varied from 0.0025 to 0.0447 μg/g and from 0.0023 to 0.0564 μg/g for U and Th, respectively. We found significant correlations between some elements in hair and nails. Also indications of spatial clustering of high values could be found. However, this phenomenon as well as the large variations in concentrations of heavy metals in hair and nail could not be explained. As hypotheses, we propose possible exposure pathways which may explain the findings, but the current data does not allow testing them.