Study of radionuclide distribution around Kudankulam nuclear power plant site (Agastheeswaram taluk of Kanyakumari district, India)

The activity concentration of primordial radionuclides 238U, 232Th and 40K have been measured in the sand samples of Agastheeswaram taluk of Kanyakumari district using gamma-ray spectrometer. The average activity of 232Th, 238U and 40K are found to be 5787.1, 1082.9 Bq kg(-1) and BDL, respectively. The total average absorbed dose rate owing to the presence of 232Th, 238U and 40K is found to be 3900.4 nGy h(-1). The annual effective dose is 4.7 mSv y(-1) and the results are discussed in this paper.     

Radioactivity concentrations and dose assessment for soil samples from Kestanbol granite area, Turkey

The concentrations and distribution of natural and anthropogenic radionuclides in soils from around the Kestanbol (Canakkale), Turkey were investigated with an aim of evaluating the environmental radioactivity and radiological health hazard. Concentrations of radionuclides in the samples were determined by gamma ray spectrometer using HPGe detector. In the soils in general, the concentration of (232)Th was found to be higher than that of the (238)U and the activities of (232)Th and (238)U in this area are higher than the world average. (137)Cs was observed in all the samples, ranging from 0.37 +/- 0.22 to 36.03 +/- 0.54 Bq kg(-1). The mean radium equivalent activity, external hazard index and terrestrial absorbed dose rate for the area under study are 498 Bq kg(-1), 1.4 and 219 nGy h(-1), respectively. The annual effective dose to the public was found to be 269 muSv. The present data were compared with data obtained from different countries.     

Radioactivity concentration in soil samples in the southern part of the West Bank, Palestine

The activity concentrations of naturally occurring radioactive materials such as (238)U, (232)Th and (40)K were measured for 38 soil samples collected from diverse zones in the southern area of West Bank, Palestine using gamma-ray spectroscopy. The measured activities of (238)U, (232)Th and (40)K were found to range from 32.9 to 104.7, 14.5 to 76.6 and 297 to 962 Bq kg(-1) with averages value of 68.7, 48.0 and 630 Bq kg(-1), respectively. The obtained values of activity concentrations are higher than the world average of 35, 30 and 500 Bq kg(-1) for (238)U, (232)Th and (40)K, respectively. The measured (137)Cs activity concentration was found to range from 1.8 to 36.1 Bq kg(-1) with an average value of 8.5 Bq kg(-1). The detected activities were attributed to the fallout of (137)Cs, which is the only man-made radionuclide. The calculated average of the total gamma-radiation dose rate of natural radionuclides, (137)Cs and cosmic radiation is 121.4 nGy h(-1). The radium equivalent activity (R(aeq)), dose rate (D(r)), external hazard index (H(ex)) and radioactivity level index (I(gamma)) in all samples are presented. Some values were found to be in the range of worldwide values, whereas others were above the worldwide values.     

Natural and artificial radioactivity distribution in soil of Fars Province, Iran

Fars province is a large populated large province located in the southwest of Iran. This work presents a study of natural and radioactivity levels in soil samples of this province. For this purpose, 126 samples were gathered from different regions of the province and analysed by gamma spectroscopy to quantify radioactivity concentrations of radionuclides using a high-purity germanium detector and spectroscopy system. The results of this investigation show the average concentrations of 271 ± 28 Bq kg(-1), 6.37 ± 0.5 Bq kg(-1), 14.9 ± 0.9 Bq kg(-1) and 26.3 ± 1.9 Bq kg(-1) for (40)K, (137)Cs, (232)Th and (238)U in soil, respectively. Finally, baseline maps were established for the concentrations of each of the radionuclides in different regions. The absorbed dose rate and the annual effective dose (AED) were also calculated for the radionuclides according to the guidelines of UNSCEAR 2000. The average AED from the radioactivity content of soil in this province was found to be 39.9 ± 1.8 μSv.     

Natural and anthropogenic radionuclides in the granitic region of Kapidag peninsula, Western Anatolia, Turkey

Naturally occurring radionuclides of terrestrial origin (also called primordial radionuclides) are present in various degrees in all media in the environment. This study represents the reports on the natural and anthropogenic radionuclides in the Kapidag granitic region. For this purpose, activities of radionuclides in soil, beach sands and rocks of the region have been investigated to assess the radiological hazard of the natural radioactivity. The radium equivalent activities, the absorbed dose rates and the external hazard indexes have been calculated, and also in situ gamma dose rates have been measured in the region. The mean activities of (238)U, (232)Th and (40)K with the ranges were determined as 31.1±15.7 (12.1-71.9), 42.5±15.9 (19.7-94.9), 590.3±192.2 (184.7-892.5), in the soil, as 16.5±9.5 (4.9-40.8), 67.1±106.9 (18.5-433.0), 569.2±212.6 (162.0-821.1) in the sand and as 25.4±12.8 (4.8-50.7), 37.8±21.5 (4.5-96.7), and 592.4±285.5 (62.4-1121.6) Bq kg(-1) in the rocks, respectively. It was also observed that the average activities of (137)Cs were ranged 0-27.8 Bq kg(-1) in the soil and 0.6-3.8 Bq kg(-1) in the beach sands. The mean Ra(eq) activities of the rocks, sands and soil were found to be 125.1±59.5, 156.3±157.2 and 137.3±48.8 Bq kg(-1), respectively, lower than the recommended maximum value of 370 Bq kg(-1) with some exceptions. The maximum contributors to the total absorbed gamma dose rates in air were determined as (238)U (45%) for the beach sands, (238)U (40%) for the soil and (40)K (41%) for rocks. The average outdoor gamma dose rates for the soil due to terrestrial and cosmic radiations were found to be 64.6±22.7 and 47.1±9.6 nGy h(-1), respectively, with the total of 111.7±29.5 nGy h(-1) outdoor gamma exposure rate and the annual average effective outdoor gamma dose was calculated as 137±36.2 μSv for the region. The results of the study were discussed with similar studies in close regions and the worldwide averages.     

Radionuclide concentrations in soils of Northern Namibia, Southern Africa

Activity concentrations of the naturally occurring radionuclides like (238)U, (232)Th and (40)K in 400 soil samples collected from four major towns across the northern region of Namibia have been determined using gamma-ray spectrometry with the objective of providing baseline data on the radiation level in the region. The average concentrations of radionuclides in the towns vary from 7.5 +/- 2.3 to 14.2 +/- 3.3 Bq kg(-1) for (238)U, 5.8 +/- 2.6 to 24.9 +/- 6.1 Bq kg(-1) for (232)Th and 52.1 +/- 28.7 to 380.1 +/- 112.9 Bq kg(-1) for (40)K. These concentrations were used to calculate the mean absorbed dose rate and the mean annual effective dose in the region. The low value of 21 +/- 16 microSv obtained for the mean annual effective dose indicates that the region has normal background radiation.     

Natural radioactivity and external gamma radiation exposure at the coastal Red Sea in Egypt

Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. In this work, superficial samples of beach sand were collected from the Red Sea coastline (Ras Gharib, Hurghada, Safaga, Qusier and Marsa Alam areas) and at 20 km on Qena-Safaga road. The distribution of natural radionuclides in sand beach samples was studied by gamma spectrometry. The activity concentrations of primordial and artificial radionuclides in samples that are collected from the coastal environment of the Red Sea were 19.2 +/- 3 Bq kg(-1) for (210)Pb, 21.1 +/- 1 Bq kg(-1) for (226)Ra, 22.7 +/- 2 Bq kg(-1) for (238)U, 1.0 +/- 0.1 Bq kg(-1) for (235)U, 11.6 +/- 1 Bq kg(-1) for (228)Ra, 13.0 +/- 1 Bq kg(-1) for (228)Th, 12.4 +/- 1 Bq kg(-1) for (232)Th, 930 +/- 32 Bq kg(-1) for (40)K and 1.2 +/- 0.3 Bq kg(-1) for (137)Cs. The mean external gamma-dose rate was 62.5 +/- 3.2 nSv h(-1), 54.4 +/- 2.8 nGy h(-1) Ra equivalent activity (Ra(eq)) was 107 +/- 5.8 Bq kg(-1), 0.86 +/- 0.04 Bq kg(-1) for representative level index (I(gamma)) and effective dose rate was 0.067 +/- 0.003 mSv y(-1) in beach sand red sea, in air due to naturally occurring radionuclides.     

A comprehensive study of natural gamma radioactivity levels and associated dose rates from surface soils in cyprus

A survey was carried out to determine activity concentration levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K, in the various geological formations of Cyprus, by means of high-resolution gamma ray spectrometry. A total of 115 representative soil samples were collected from all over the bedrock surface of the island, based on the different lithological units of the study area, sieved through a fine mesh, sealed in 1000 ml plastic Marinelli beakers and measured in the laboratory with respect to gamma radioactivity for a counting time of 18-h each. From the measured spectra, activity concentrations were determined for 232Th (range from 1.0 x 10(-2) to 39.8 Bq kg(-1)), 238U (from 1.0 x 10(-2) to 39.3 Bq kg(-1)) and (40)K (from 4.0 x 10(-2) to 565.8 Bq kg(-1)). Gamma absorbed dose rates in air outdoors were calculated to be in the range from 1.1 x 10(-2) to 51.3 nGy h(-1), depending on the geological features, with an overall mean value of 8.7 nGy h(-1) and a standard deviation of 8.4 nGy h(-1). This value is by a factor of about seven below the corresponding population-weighted world-averaged value of 60 nGy h(-1) and one of the lowest that has been reported from similar investigations worldwide. Assuming a 20% occupancy factor, the corresponding effective dose rates outdoors equivalent to the population were calculated to be between 1.3 x 10(-2) and 62.9 microSv y(-1), with an arithmetic mean value of 10.7 microSv y(-1) and a standard deviation of 10.3 microSv y(-1).     

Radiological significance of beach sand used for climatotherapy from Safaga, Egypt

As a part of national survey to evaluate natural radioactivity in the environment, concentration levels of radioactivity were analysed for sand samples from Safaga, Egypt, which is an ideal area for climatotherapy of psoriasis. Gamma dose rates of three beaches in Safaga were measured. The values ranged from 195.1 to 210.7 nGy h(-1). The activity concentrations (Bq kg(-1)) of radionuclides 238U series, 232Th series and 40K in three different sand profiles (0-5, 5-10, 10-15, 15-25 and 25 - 40 cm) were measured using gamma-ray spectrometry. The annual effective doses were 259 microSv y(-1) for Minveila, 255 microSv y(-1) for Ganet Safaga and 239 microSv y(-1) for Masab El-Ghazel beaches. The dose rates, radium equivalent activities and external hazard indices were evaluated and compared with the international data. These results may contribute to the determination of absorbed dose rate reference levels in Red Sea Coast at Safaga city.     

A study of environmental radioactivity measurements for Cankiri, Turkey

This study is the first to assess the level of background radiation for the Cankiri province of Turkey. Indoor air radon concentrations were determined using Columbia Resin-39 nuclear track detectors and the average (222)Rn activity was found to be 44 Bq m(-3) (equivalent to an annual effective dose of 1.1 mSv). Measurements of gamma doses in outdoor air were performed using a portable plastic scintillation detector and the average gamma absorbed dose rate was found to be 8 μR h(-1) (corresponding to an annual effective dose of 87.7 μSv). Radionuclide activity concentrations in soil samples were measured through gamma-ray spectrometry and the average activities were determined as 17.7, 22.3, 357 and 4.1 Bq kg(-1) for the radionuclides (238)U, (232)Th, (40)K and (137)Cs, respectively. The average annual effective dose from the natural radioactivity sources ((238)U series, (232)Th series and (40)K) was calculated to be 44.4 μSv. Radioactivity levels of drinking water samples were carried out using a low-background proportional counter and the average gross alpha and beta activities were obtained as 0.25 and 0.26 Bq l(-1), respectively (equivalent to an annual effective dose of 184 μSv). The average radon concentrations in indoor air and the average radionuclide activities in soil were found to be lower than most Turkish cities while higher levels of outdoor gamma dose rate and water radioactivity were observed. The results of this study showed that the region's background radioactivity level differs considerably from the reported data for Turkish cities.     

Assessment of the natural radioactivity in the soils of Windhoek city, Namibia, Southern Africa

The radioactivity concentrations of (238)U, (232)Th and (40)K in 160 soil samples collected from 16 geographical areas across Windhoek city, Namibia, have been determined using an HPGe detector and found to vary from 15.0 +/- 1.3 to 37.8 +/- 2.1 Bq kg(-1) for (238)U, 17.5 +/- 2.7 to 62.1 +/- 3.3 Bq kg(-1) for (232)Th and 168.9 +/- 15.0 to 784.9 +/- 30.1 Bq kg(-1) for (40)K. These concentrations were used to calculate the mean absorbed dose rate and the mean annual effective dose for the city. The value of 0.07 +/- 0.01 mSv y(-1) obtained for the mean effective dose is less than the maximum permissible dose of 1 mSv y(-1) recommended for the public by the International Commission on Radiological Protection.     

Assessment of natural radioactivity concentrations and gamma dose rate levels in Kayseri, Turkey

This study assesses the level of background radiation for Kayseri province of Turkey. Natural radionuclide activity concentrations in soil samples were determined using high-resolution gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using a portable gamma scintillation detector. The obtained results of uranium and thorium series as well as potassium ((40)K) are discussed. The present data were compared with the data obtained from different areas in Turkey. From the measured gamma-ray spectra, the average activity concentrations were determined for (238)U (range from 3.91 to 794.25 Bq kg(-1)), (232)Th (range from 0.68 to 245.55 Bq kg(-1)) and (40)K (range from 23.68 to 2718.71 Bq kg(-1)). The average activity concentrations of (238)U, (232)Th and (40)K were found to be 35.51, 37.27 and 429.66 Bq kg(-1), respectively, and 11.53 Bq kg(-1) for the fission product (137)Cs. The highest values of (238)U, (232)Th and (40)K concentrations (794.25 Bq kg(-1), 245.55 Bq kg(-1), 2718.71 Bq kg(-1), respectively) were observed in abnormal samples at Hayriye village. The average outdoor gamma dose rate in air at 1 m above the ground was determined as 114.43 nGy h(-1). Using the data obtained in this study, the average annual effective dose for a person living in Kayseri was found to be about 140.34 μSv.     

Measurement of radioactivity in the soil of Bahawalpur division, Pakistan

Bahawalpur is the largest division of the Punjab province in Pakistan. It is larger than many countries of the world. Gamma activity from the naturally occurring radionuclides namely 226Ra, 232Th, the primordial radionuclide 40K and the artificial radionuclide 137Cs was measured in the soil of the Bahawalpur division using gamma spectrometry technique. The mean activity of 226Ra, 232Th, 40K and 137Cs were found to be 32.9 +/- 0.9, 53.6 +/- 1.4, 647.4 +/- 14.1 and 1.5 +/- 0.2 Bq kg(-1), respectively. The mean radium equivalent activity Raeq, external hazard index, internal hazard index and terrestrial absorbed dose rate for the area under study are 158.5 +/- 4.1 Bq kg(-1), 0.4, 0.5 and 77.32 nGy h(-1), respectively. The annual effective dose equivalent to the public was found to be 0.5 mSv.     

Exposure of workers in Tusnica coal mine

The aim of this paper is to identify potential exposure of the workers in the coal mine Tusnica. The results of the investigation showed increased activity of brown coal up to 1060 ± 88 Bq kg(-1) for (238)U, 976 ± 30 Bq kg(-1) for (226)Ra and 118 ± 31 Bq kg(-1) for (232)Th. Dose rate measurements ranged from 0.07 to 0.25 μSv h(-1). The annual effective dose, taking into account external exposure to ambient gamma radiation and internal exposure due to inhalation of the resuspended dust, would be 1.6 mSv a(-1). The results presented lead to the conclusion that Tusnica coal mine contains brown coal with significant radioactivity, indicating that the working hours in the area should be regulated and the use of respiratory protective equipment is obligatory.     

Radioactivity risk associated with the handling of compact fluorescent lamps

The objective of this work is focused in measuring the level of naturally occurring radionuclides in compact fluorescent lamps commonly used in Egypt. The activity concentration of radionuclides in the (238)U and (232)Th decay chains and from (40)K were determined through gamma-ray spectrometry measurements using high-purity germanium in a low-background configuration. It was found that the activity concentrations ranged from 45 to 198 Bq kg(-1) for (238)U, from 30 to 191 Bqkg(-1) for (232)Th and from 419 to 935 Bq kg(-1) for (40)K.     

Natural and artificial radionuclide measurements and radioactivity assessment of soil samples in eastern Sichuan province (China)

The activity concentrations of natural and artificial radionuclides were measured in the eastern region of Sichuan province (China). One hundred and ninety-three soil samples from this region were collected and analysed by high-purity germanium gamma spectrometry. The measured results show that the average radioactivity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in the soil samples are 26, 49, 440 and 6 Bq kg(-1), respectively. The calculated average radium equivalent activity is 130 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1). The absorbed dose rate and annual effective dose are 60 nGy h(-1) and 74 μSv, respectively. This is the first time the absorbed dose rate in the east region of Sichuan has been mapped. Overall, the environmental radiation background is greater in the southern part of the area studied than in the northern.     

Gis predictive mapping of terrestrial gamma radiation in the Northern state, Sudan

This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from (238)U and (232)Th series, (40)K and (137)Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of (238)U, (232)Th , (40)K and (137)Cs in soil samples collected from different locations have been measured using high-resolution gamma spectrometry. On average, activity concentrations were 19±4 ((238)U), 47±11 ((232)Th), 317±65 ((40)K) and 2.26 Bq kg(-1) for (137)Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h(-1), indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 μSv y(-1). Using GIS, prediction maps for concentrations of (238)U, (232)Th, (40)K and (137)Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State.     

Assessment of background radioactivity level for Gaziantep region of southeastern Turkey

This study presents the measurement results of environmental radioactivity levels for Gaziantep, an industrial and trade centre in the southeastern part of Turkey. The outdoor gamma absorbed dose was measured as 50.1 nGy h(-1), corresponding to a total gamma radiation level (of terrestrial and cosmic origin) of 61.5 microSv y(-1). The activity concentrations in the surface soil samples collected from the study area were determined as 25.2, 23.7 and 289.2 Bq kg(-1) for the natural radionuclides (238)U, (232)Th and (40)K, respectively, and 8.02 Bq kg(-1) for the fission product (137)Cs. These natural radioactivity sources result in a terrestrial gamma level of 46.9 microSv y(-1). The drinking water samples collected from the region carry an average of 0.0493 Bq l(-1) of gross alpha and 0.1284 Bq l(-1) of gross beta activities, which together cause an annual effective dose of 1.83 microSv. The measurement results obtained in this study indicate that the region has a background radiation level that is within the natural limits and shows no significant departure from the other parts of the country.     

Radiation dose in the high background radiation area in Kerala, India

A systematic radiological survey has been carried out in the region of high-background radiation area in Kollam district of Kerala to define the natural gamma-radiation levels. One hundred and forty seven soil samples from high-background radiation areas and five samples from normal background region were collected as per standard sampling procedures and were analysed for (238)U, (232)Th and (40)K by gamma-ray spectroscopy. External gamma dose rates at all sampling locations were also measured using a survey meter. The activities of (238)U, (232)Th and (40)K was found to vary from 17 to 3081 Bq kg(-1), 54 to 11976 Bq kg(-1) and BDL (67.4 Bq kg(-1)) to 216 Bq kg(-1), respectively, in the study area. Such heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of beach sand soil in the region. Radium equivalent activities were found high in several locations. External gamma dose rates estimated from the levels of radionuclides in soil had a range from 49 to 9244 nGy h(-1). The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples.     

Natural radioactivity measurements in beach-rock samples of south-east coast of Tamilnadu, India

The concentration of primordial radionuclides in beach-rock samples of the south-east coast of Tamilnadu, India has been measured using gamma ray spectrum of rock. The mean activities of 232Th, 238U and 40K are 144.18, 29.25 and 267.48 Bq kg(-1) respectively. In situ measurements were also carried out using environmental radiation dosemeter. The linear correlation coefficient was obtained. The average activity of concentration of 232Th in the present study is 2.5 times higher than the world median value while the activity of 238U and 40K were found to be lower. This may be due to the heavy minerals present in the study area. In the present study, the calculated activity ratio (Th/U) is higher than the crustal rocks. This may be due to changes in the crustal composition through time (mafic to felsic) that are reflected by a change in the Th and U abundances in sedimentary rocks, and also increase in carbon content with time resulted in the decrease in U content and increase in Th/U ratio.