Natural radioactivity concentrations of 226Ra, 232Th,and 40K in commercial building materials and their lifetime cancer risk assessment in dwellers

Elevated radioactivity levels of ²²⁶Ra, ²³²Th, and ⁴⁰K in building materials were measured using gamma-ray spectrometry and their associated lifetime cancer risks were also determined. The mean activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are 45.72 ± 0.55, 65.90 ± 8.89, and 487.32 ± 15.20 Bq kg^?1, respectively. Statistically, the principal component (PC) analysis indicates that higher loadings were recorded in Principal Component One (PC1) with large contribution from ²³²Th and ⁴⁰K. The leverage studies indicate that BN Ceramics (BNC) contributes more to the loadings in PC1 followed by Golden Crown Ceramic (GCC) sample. The mean values of 0.399 mSv y^?1 do not surpass the world average value of 0.7 mSv y^?1. The mean gamma index from the measured samples is 0.644, whereas a mean value of 0.271 for alpha index is noted in the samples. The activity utilization index (AUI) from the samples satisfied the AUI <2, which corresponded with the annual effective dose of <0.3 mSv y^?1, except interlock Site 2 and Gomez Spain tiles. Significantly, the mean value of excess lifetime cancer risk of 0.0014 is slightly lower than the world average value of 0.29 × 10^?3.     

Activity concentrations of <Superscript>226</Superscript>Ra, <Superscript>228</Superscript>Th,and <Superscript>40</Superscript>K in different food crops from a high background radiation area in Bitsichi,Jos Plateau,Nigeria

One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations of ²²⁶Ra, ²²⁸Th, and ⁴⁰K were determined in the food and soil samples using γ-ray spectrometry. Additionally, in situ gamma dose rate measurements were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops ranged from below detection limit (BDL) to 684.5 Bq kg⁻¹ for ⁴⁰K, from BDL to 83.5 Bq kg⁻¹ for ²²⁶Ra, and from BDL to 89.8 Bq kg⁻¹ for ²²⁸Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg⁻¹, from 10.9 to 470.6 Bq kg⁻¹, and from 122.7 to 2,189.5 Bq kg⁻¹ for ⁴⁰K, ²²⁶Ra, and ²²⁸Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 ± 0.01 to 1.47 ± 0.04 μSv h⁻¹. Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake of these radionuclides by the food crops is low and that harmful health effects are not expected.     

Spatial distributions and dose assessment of natural radionuclides in rocks and soils of some selected sites in southwestern Nigeria

The activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in rock and soil samples collected from Ondo and Ekiti States in southwestern Nigeria were measured by using gamma-ray spectrometer with a high-purity germanium (HPGe) detector. The mean activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in the rock were 25.53, 61.12, and 554.20 Bq kg^?1 respectively, while that of the soil were 8.27, 17.37, and 151.72 Bq kg^?1 respectively. Results showed that the activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were higher in the rocks than the soils of the areas studied. To assess the radiological impact of some radionuclides on the population in the region, the annual effective dose equivalent (AEDE), annual gonadal equivalent dose (AGED), and excess lifetime cancer risk (ELCR) were calculated. The mean values of the indoor and outdoor AEDE, and AGED were 88.08 µSv y^?1, 352.34 µSv y^?1, and 508.40 mSv y^?1, respectively for the rock samples, and 25.31 µSv y^?1, 101.25 µSv y^?1, and 145.80 mSv y^?1 respectively for the soil samples. The mean values obtained for AEDE and AGED for the soil were below ICRP recommended limits of 1 and 300 mSv y^?1, respectively. AGED for the rocks was higher than the maximum permissible limit.     

Radionuclides content in grape molasses soil samples from Central Black Sea region of Turkey

The activity concentrations of radionuclides in grape molasses soil samples collected from Zile (Tokat) plain in the Central Black Sea region of Turkey were measured by using gamma spectrometer with a NaI(Tl) detector. Also, the concentrations of ²²²Rn in soil samples and air were estimated essentially taking the activity concentrations of ²²⁶Ra measured in soil samples. Grape molasses soil samples with calcium carbonate content are used for sedimentation for making molasses in this region. The average activity concentrations of ²³²Th, ²²⁶Ra, ⁴⁰K, and ¹³⁷Cs were found as 62 ± 2, 68 ± 3, 479 ± 35, and 8.0 ± 0.3 Bq kg^?1, respectively. The average concentrations of ²²²Rn in soil samples and air were estimated to be 50 kBq m^?3 and 144 Bq m^?3. From the activity concentrations, absorbed gamma dose rate in outdoor air (D), annual effective dose from external exposure (E_E), annual effective dose from inhalation of radon (E_I), and excess lifetime cancer risk (ELCR) were estimated in order to assess radiological risks. The average values of D, E_E, E_I, and ELCR were found to be 90 nGy h^?1, 110 μSv y^?1, 1360 μSv y^?1, and 4 × 10^?4, respectively.     

Radium-226 levels in the Cauvery river ecosystem, India

We studied the natural radioactivity distribution of an α-emitting radionuclide,²²⁶Ra in water, sediment and biota (plankton, weed, snail, bivalve, prawn and fish) of Cauvery river ecosystem extending a stretch of 95 km. The dissolved²²⁶Ra concentration in river water ranged from 0.82mBq.I^-1 to l 06mBq.l^-1 (mean: 0.93mBq.l^-1) and the activity in river sediments from 4.7Bq.kg^-1 to 6.9Bq.Kg^-1 (mean: 5.6Bq.kgg^-1 dry wt.). The²²⁶Ra activity levels in the biota were within a narrow range from below detection limit to 3.80 Bq.kg^-1 (wet wt). Generally higher²²⁶Ra concentrations are observed in the shells and bones of aquatic organisms than in their tissues and muscles. The concentration factors (CFs) of²²⁶Ra for the biotic components ranged from ∼10¹ to ∼10³. The significance of²²⁶Ra activity in the abiotic and biotic components of Cauvery river are discussed.     

Assessments of 226Ra and 222Rn concentration in well and tap water from Sik,Malaysia, and consequent dose estimates

Abstract

The ingestion of ²²⁶Ra, inhalation, and ingestion of ²²²Rn in water is considered the primary health risk for lungs and stomach. This study presents the concentrations of ²²⁶Ra and ²²²Rn in well and tap water collected from Sik, Malaysia, using HPGe and RAD7 detectors. Maximum average concentrations of ²²⁶Ra and ²²²Rn were found 47.6?±?3.6 mBq/l and 9.3?±?1.4?Bq/l in well water, respectively, and minimum were found 17.1?±?3.6 mBq/l and 1.6?±?1.0?Bq/l in tap water, respectively. A positive correlation (R=.88) was found between ²²⁶Ra and ²²²Rn determined by HPGe and RAD7 detectors, respectively. Infants in the age group of 0–1 y appeared to be at risk with respect to the annual effective doses from ²²⁶Ra and ²²²Rn as compared to the other age groups. However, annual effective doses for all three age groups from intake of ²²⁶Ra and ²²²Rn in well and tap drinking water were found below the World Health Organization (WHO) recommended level of .1 mSv/y_.     

Risk assessment of natural radioactivity in surface water and sediments from a waterfall site in Osun State,Nigeria

Activity concentration of natural radionuclides in surface water and sediment from a waterfall site, Erin-Oke, Osun, Nigeria, has been determined by gamma spectrometry. The mean activity concentration of ⁴⁰K, ²²⁶Ra, and ²³²Th were estimated to be 61.015 ± 15.50, 8.165 ± 2.05 and 5.24 ± 1.57 Bq/l, respectively in water samples and 172.023 ± 35.433, 19.282 ± 4.95, and 17.089 ± 4.37 Bq/kg respectively in sediment samples. Total annual effective dose ingested by an individual ranges from 10.73 ± 3.36 to 15.18 ± 4.44 mSv/y, 2.50 ± 0.80 to 3.58 ± 0.96 mSv/y, and 2.30 ± 0.72 to 3.23 ± 0.93 mSv/y, with mean values of 13.25 ± 3.89, 3.10 ± 0.90, and 2.83 ± 0.83 mSv/y for infants, children, and adults, respectively. These values are greater than International Commission on Radiological Protection (ICRP) and the World Health Organization's recommended limit of 1.0 and 0.1 msv/y, respectively. Mean activity concentrations in sediment are 172.023 ± 35.433, 19.823 ± 4.95, and 17.089 ± 4.37 Bq/kg for ⁴⁰K, ²²⁶Ra, and ²³²Th, respectively, with mean absorbed dose of 26.91 nGyh^?1. This value is lesser than UNSCEAR world average value of 55 nGyh^?1. Health hazard index and radium equivalent for sediments showed lower values than absorbable limits.     

Statistical analysis of natural radioactivity data of clay samples in Tiruvannamalai,Tamilnadu, India

The activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K were determined in clay samples collected from Tiruvannamalai district, Tamilnadu using gamma ray spectrometry. The determined activity concentration ranges from BDL to 16 Bq Kg⁻¹, 18 to 192 Bq Kg⁻¹, 288 to 901 Bq Kg⁻¹ for ²²⁶Ra, ²³²Th and ⁴⁰K respectively. The concentration of these radionuclides is compared with world average values. Radiological risk evaluation was done by calculating radium equivalent activity (Ra_eq), absorbed gamma dose rate (D_R), annual effective dose rate (H_R), annual gonadal dose equivalent (AGDE), criteria formula (CF), representative level index (RLI), activity utilization index (AUI), gamma index (Iγ), alpha index ((Iα), the external hazard (Hex) and internal hazard (Hin) due to internal exposure to radionuclides distributed in clay samples. Multivariate statistical techniques were used to study the relation between activity concentration and radiation hazards of clay samples.     

Estimation of dose rate for indoor radon from building materials

The internal dose rate due to indoor radon (Rn) emissions from building materials is estimated. It is observed that the contribution from building materials to the dose rate is very small. The average indoor radon concentration in 75 different rooms is found to be 55 ± 12 Bq. m^–3. Assuming an occupancy factor of 0.8, the annual average effective dose equivalent is 1.7 mSv. It seems that soil gas is mainly responsible for the internal exposure from indoor Rn.     

Natural radioactivity concentrations and dose assessment in coastal sediments along the East Coast of Tamilnadu,India with statistical approach

The present study was conducted to determine the activity concentration of ²³⁸U, ²³²Th and ⁴⁰K in coastal sediments samples from Poombuhar to Karaikal along East coast of Tamilnadu, India using gamma ray spectrometry. The average activity concentration for ²³⁸U, ²³²Th and ⁴⁰K were obtained as 36.82 (Bq kg⁻¹), 50.11(Bq kg⁻¹) and 320.38 (Bq kg⁻¹), respectively. These obtained results were used to calculate the radiological hazard parameters like radium equivalent activity (Ra_eq), absorbed gamma dose rate (D_R), the annual effective dose equivalent (AEDE), Annual gonadal dose equivalent (AGDE), Activity utilization index (AUI), External hazard index (H_ex), Internal hazard index (H_in), Gamma representative level index (RLI) and Excess lifetime cancer risk (ELCR). The computed radiological parameters values are compared with the internationally approved recommended values. The multivariate statistical method is used to simplify and organize large data sets to indicate natural associations between samples and variables.     

Measurement of activity concentrations of <Superscript>40</Superscript>K, <Superscript>226</Superscript>Ra and <Superscript>232</Superscript>Th for assessment of radiation hazards from soils of the southwestern region of Nigeria

Activity concentrations of the selected radionuclides ⁴⁰K, ²²⁶Ra and ²³²Th were measured in surface soil samples collected from 38 cities in the southwest region of Nigeria by means of gamma spectroscopy with a high-purity germanium detector. Measured activity concentration values of ⁴⁰K varied from 34.9 ± 4.4 to 1,358.6 ± 28.5 Bq kg⁻¹ (given on a dry mass (DM) basis) with a mean value of 286.5 ± 308.5 Bq kg⁻¹; that of ²²⁶Ra varied from 9.3 ± 3.7 to 198.1 ± 13.8 Bq kg⁻¹ with a mean value of 54.5 Bq kg⁻¹ and a standard deviation of 38.7 Bq kg⁻¹, while that of ²³²Th varied from 5.4 ± 1.1 to 502.0 ± 16.5 Bq kg⁻¹ with a mean value of 91.1 Bq kg⁻¹ and standard deviation of 100.9 Bq kg⁻¹. The mean activity concentration values obtained for ²²⁶Ra and ²³²Th are greater than the world average values reported by the United Nations Scientific Committee on Effects of Atomic Radiation for areas of normal background radiation. Radiological indices were estimated for the radiation/health hazards of the natural radioactivity of all soil samples. Estimated absorbed dose rates in air varied from 12.42 ± 2.25 to 451.33 ± 19.06 nGy h⁻¹, annual outdoor effective dose rates from 0.015 ± 0.003 to 0.554 ± 0.023 mSv year⁻¹, internal hazard index from 0.10 ± 0.03 to 3.02 ± 0.16, external hazard index from 0.07 ± 0.01 to 2.60 ± 0.11, representative level index from 0.19 ± 0.03 to 6.84 ± 0.29, activity index from 0.09 ± 0.02 to 3.42 ± 0.15, and radium equivalent activity from 26.95 ± 5.04 to 963.15 ± 41.87 Bq kg⁻¹. Only the mean value of the representative level index exceeds the limit for areas of normal background radiation. All other indices show mean values that are lower than the recommended limits.     

Radionuclide concentrations in the diet of residents in a high level natural radiation area in Iran

Concentrations of ¹³⁷Cs and ²²⁶Ra in the diet (foodstuffs and drinking water) of adult inhabitants in the high-level natural radiation area (HLNRA) of Ramsar, Iran have been determined. The annual intake of foodstuffs was estimated on the basis of their average annual consumption. Food samples collected from local markets were analyzed by means of a gamma spectrometer. The estimated annual dietary intakes of ¹³⁷Cs and ²²⁶Ra were 130Bq and 245Bq, respectively. The concentrations of natural radionuclides in food and drinking water of the residents are higher than the world average, and are correlated with the high concentration of these radionuclides in soil and water. Calculations were also made to determine the potential dose to an individual consuming such diets.     

JM-1232(−) and propofol,a new combination of hypnotics with short-acting and non-cumulative preferable properties

Drug interactions are significant in anesthesiology because drug combinations can potentially possess novel properties. The pharmacological advantages of a new combination of the benzodiazepine receptor agonist JM-1232(−) and propofol were investigated in mice. Male adult mice were administered JM-1232(−) or propofol or combinations of the two drugs intravenously. Loss of the righting reflex was evaluated as achieving hypnosis, and the time until recovery of the reflex was measured as hypnosis time. After determining the ED₅₀, doses double and triple the ED₅₀ of propofol were injected with JM-1232(−) to compare hypnosis time. The injections were repeated four times, and the hypnosis times were compared. Flumazenil was administered separately immediately after the last dose was injected. The ED₅₀ values ([95% confidence interval]) for hypnosis were 3.76 [3.36–4.10] for JM-1232(−) and 9.88 [8.03–11.58] mg kg⁻¹ for propofol. Co-administration of 0.5 and 1 mg kg⁻¹ JM-1232(−) reduced the ED₅₀ values of propofol to 1.76 [1.21–2.51] and 1.00 [0.46–1.86] mg kg⁻¹, respectively. The drug combination for hypnosis produced a supra-additive interaction. Hypnosis time was significantly shorter in the groups given the mixtures compared to each hypnotic administered alone. After repeated injections, hypnosis time with the mixtures showed smaller prolongation than that with the hypnotic alone. Flumazenil completely restored the recovery time after anesthesia. The combination of JM-1232(−) and propofol showed a supra-additive interaction, and the reduced hypnotic dose contributed to a faster recovery even after multiple injections.     

Determination of 17 Organophosphate Pesticide Residues in Mango by Modified QuEChERS Extraction Method Using GC-NPD/GC-MS and Hazard Index Estimation in Lucknow,India

A total of 162 samples of different varieties of mango: Deshehari, Langra, Safeda in three growing stages (Pre-mature, Unripe and Ripe) were collected from Lucknow, India, and analyzed for the presence of seventeen organophosphate pesticide residues. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method of extraction coupled with gas chromatography was validated for pesticides and qualitatively confirmed by gas chromatography- mass spectrometry. The method was validated with different concentrations of mixture of seventeen organophosphate pesticides (0.05, 0.10, 0.50 mg kg⁻¹) in mango. The average recovery varied from 70.20% to 95.25% with less than 10% relative standard deviation. The limit of quantification of different pesticides ranged from 0.007 to 0.033 mg kg⁻¹. Out of seventeen organophosphate pesticides only malathion and chlorpyriphos were detected. Approximately 20% of the mango samples have shown the presence of these two pesticides. The malathion residues ranged from ND-1.407 mg kg⁻¹ and chlorpyriphos ND-0.313 mg kg⁻¹ which is well below the maximum residues limit (PFA-1954). In three varieties of mango at different stages from unpeeled to peeled sample reduction of malathion and chlorpyriphos ranged from 35.48%–100% and 46.66%–100% respectively. The estimated daily intake of malathion ranged from 0.032 to 0.121 µg kg⁻¹ and chlorpyriphos ranged from zero to 0.022 µg kg⁻¹ body weight from three different stages of mango. The hazard indices ranged from 0.0015 to 0.0060 for malathion and zero to 0.0022 for chlorpyriphos. It is therefore indicated that seasonal consumption of these three varieties of mango may not pose any health hazards for the population of Lucknow, city, India because the hazard indices for malathion and chlorpyriphos residues were below to one.     

Radiocesium decay in populations of brown trout and Arctic char in the alpine Atna area, south-eastern Norway

Some of the highest recordings of radioactive fallout from the Chernobyl accident in Norway were found in the south-eastern Oppland and Hedmark counties. Cesium content and decay rates were followed in populations of brown trout and Arctic char in Lake Atnsjøen over the years 1986–1995. These results were compared with samples for adjacent lakes to test for between-lake variabilities within the same region. The data on brown trout was compared with samples from a wider region, where more than 1800 individual samples of brown trout were collected from nearly 100 localities. Back-calculated initial activity per 1 January 1987 showed a strong regional and within-lake variability for these localities, ranging from 437 to 18000 Bq kg^–1 (average: 2416 Bq kg^–1), while trout and char from Atnsjøen had initial activities of 1259 and 1122 Bq kg^–1, respectively. Most of the other populations from the Atna region also had initial activities below the average (around 2000 Bq kg^–1). Ecological half-life for both brown trout and Artic char in lake Atnsjøen was close to 1.7 years (corresponding to a decay rate of 0.4 year), which was consistently lower than the 2.5 years average for the entire lake data set. Decay constants from linear regressions of total decay over time ranged from 0.15 to 0.28. For trout populations, a positive correlation was found between initial load and decay constants. Although trout and char clearly differ in their diet, no consistent differences were recorded in initial activities or decay rates for these two species in the Atna area.     

Evaluation of the mutagenicity and antimutagenicity of Ziziphus joazeiro Mart. bark in the micronucleus assay

The aim of this study was to evaluate the mutagenicity (clastogenicity/aneugenicity) of a glycolic extract of Ziziphus joazeiro bark (GEZJ) by the micronucleus assay in mice bone marrow. Antimutagenic activity was also assessed using treatments associated with GEZJ and doxorubicin (DXR). Mice were evaluated 24–48 h after exposure to positive (N-nitroso-N-ethylurea, NEU - 50 mg.kg⁻¹ and DXR - 5 mg.kg⁻¹) and negative (150 mM NaCl) controls, as well as treatment with GEZJ (0.5–2 g.kg⁻¹), GEZJ (2 g.kg⁻¹) + NEU and GEZJ (2 g.kg⁻¹) + DXR. There were no significant differences in the frequencies of micronucleated polychromatic erythrocytes in mice treated with GEJZ and GEJZ + DXR compared to the negative controls, indicating that GEZJ was not mutagenic. Analysis of the polychromatic:normochromatic erythrocyte ratio revealed significant differences in the responses to doses of 0.5 g.kg⁻¹ and 1–2 g.kg⁻¹ and the positive control (NEU). These results indicated no systemic toxicity and moderate toxicity at lower and higher doses of GEZJ. The lack of mutagenicity and systemic toxicity in the antimutagenic assays, especially for treatment with GEZJ + DXR, suggested that phytochemical compounds in Z. joazeiro bark attenuated DXR-induced mutagenicity and the moderate systemic toxicity of a high dose of Z. joazeiro bark (2 g.kg⁻¹). Further studies on the genotoxicity of Z. joazeiro extracts are necessary to establish the possible health risk in humans and to determine the potential as a chemopreventive agent for therapeutic use.     

Measurement of <Superscript>131</Superscript>I activity in thyroid of nuclear medical staff and internal dose assessment in a Polish nuclear medical hospital

This paper presents results of ¹³¹I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined ¹³¹I activity was found to be above the detection limit (DL = 5 Bq of ¹³¹I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.     

Distribution of 226Ra body burden of workers in an underground uranium mine in India

Uranium mine workers are exposed to ore dust containing uranium and its daughter products during different mining operations. These radionuclides may pose inhalation hazards to workers during the course of their occupation. The most significant among these radionuclides is ²²⁶Ra. The measurement of radium body burden of uranium mine workers is important to assess their internal exposure. For this purpose, the radon-in-breath measurement technique has been used in the present paper. Workers at the Jaduguda mine, India, associated with different categories of mining operations were monitored between 2001 and 2007. The measurement results indicate that workers—depending on mining operation category—show ²²⁶Ra body burdens ranging from 0.15 to 2.85 kBq. The maximum body burden was found for workers associated with timbering operations, with an average ²²⁶Ra body burden of 0.85 ± 0.54 kBq. Overall, the average value observed for 800 workers was 0.76 ± 0.51 kBq, which gives rise to an average effective dose of 1.67 mSv per year for inhalation and 0.21 mSv per year for ingestion.     

Preliminary dose estimation from indoor radon for the medical staff of Radiation Oncology and Nuclear Medicine

The aim of this preliminary study was to measure the indoor radon activity concentration in the houses and offices of Radiation Oncology and Nuclear Medicine staff at Dokuz Eylül University and to assess the results from a radiological perspective. LR-115 type II solid-state nuclear track detectors were installed in the homes and hospital and were exposed for 2 months. LR-115 type II detectors were etched for 90 min in 10% (2.5 M) NaOH solution at 60°C and radon activity concentration was determined from observed microscopic track densities. It was observed that measured indoor radon concentration ranged between 18 and 624 Bq/m³ with a geometric mean of 95 Bq/m³ in hospital, and between 22 and 560 Bq/m³ with a geometric mean of 129 Bq/m³ in homes. Estimates of the annual effective dose received by medical staff who participated in the study ranged between 0.76 and 8.79 mSv. On average, the hospital building contributed 41% to the annual effective dose. The reported values for radon concentrations and the corresponding estimated annual effective equivalent doses were within the limits recommended by the International Commission on Radiological Protection as well as the Turkish Atomic Energy Commission recommended limits for workplaces and houses.     

Measurements of radioactivity in environmental samples from the Southern Urals

A region between Chelyabinsk and Ekaterinburg in the Southern Urals has been heavily contaminated due to operational and accidental releases from the first Soviet plutonium production facility Mayak. In 1992 and 1993, the German Federal Office for Radiation Protection organized a measuring campaign involving two Russian institutes to assist with the validation of former Soviet measurement data. The results of this measuring campaign are reported here. Environmental samples were collected from areas affected by significant radioactive releases into the Techa river, which started in 1948, and by fallout from the explosion of a fission product storage tank in 1957. Soil, sediment, water, milk and food samples were independently analysed for ⁹⁰Sr, ¹³⁷Cs and plutonium by the three institutes involved. This paper presents data on the present levels of environmental radioactivity. The highest contamination of areas accessible to the local population was found in the vicinity of the Techa river around Muslumovo. Activity concentration of floodplain samples reached up to 37 000 Bq ⋅ kg^{–1 137}Cs, 5 600 Bq ⋅ kg^{–1 90}Sr and 9.9 Bq ⋅ kg^–1 Pu. Milk and potatoes from private farms in Muslumovo showed low activity in the range from 0.7 Bq ⋅ kg^–1 to 25 Bq ⋅ kg^{–1 90}Sr. The results of the three independent measurement teams showed sufficient agreement. One Russian laboratory obtained plutonium activities that exceeded the results of the other laboratories by about 20%. Contrary to the International Chernobyl Project, there was no overestimation of ⁹⁰Sr activities in the Russian analyses. Therefore, the validity of earlier data sets acquired with same methodology and quality control can be considered a valuable basis for further assessments and for dose reconstruction in epidemiological projects. Received: 18 July 1997 / Accepted in revised form: 19 December 1997