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.     

Radioactivity concentrations and dose assessment in surface soil samples from east and south of Marmara region, Turkey

The activity concentrations of 137Cs, 40K, 232Th, 238U and 226Ra were measured in surface soil samples from East and South of Marmara region, Turkey. The physico-chemical parameters (organic matter, CaCO3 contents and pH-value) of the soil samples were determined in the samples collected from 100 sampling stations. The average activity concentrations of 137Cs, 40K, 232Th, 238U and 226Ra were found to be 27.46+/-21.84, 442.51+/-189.85, 26.63+/-15.90, 21.77+/-12.08 and 22.45+/-13.31 Bq kg(-1), respectively. The mean value of total annual external gamma radiation dose equivalent for the natural radionuclides was calculated to be 54.86 microSv. The current data were compared with those found in the other locations of Turkey and different countries.     

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.     

Assessment of radionuclide level in topsoil samples for partial areas of Tibet, China

By using high-purity germanium gamma spectroscopy, specific activities of naturally occurring and man-made radionuclides were determined in topsoil samples collected from Nyingch, Lhasa and Xigazê of Tibet Autonomous Region, China. The average activity concentrations of (226)Ra, (232)Th and (40)K were 25.1 ± 0.7, 67.1 ± 2.8 and 608.6 ± 12.9 Bq kg(-1), respectively. The activity concentration of (137)Cs was found to vary from <0.3 (minimum detection concentration) to 46.2 Bq kg(-1) with an average of 4.3 ± 0.5 Bq kg(-1). By using the results of (226)Ra, (232)Th and (40)K in the sampled soils, the average outdoor gamma dose rate in air was calculated as 77.5 ± 23.2 nGy h(-1). Furthermore, the average outdoor annual effective dose from terrestrial radiation was 0.10 mSv. The external hazard index in this work varied from 0.20 to 0.70 with an average of 0.40 ± 0.14. The external exposure from terrestrial radiation will not pose any significant radiological threat to the population resident in the studied areas.     

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.     

Measurements of activity concentrations of naturally occurring radionuclides in soil samples from Punjab province of Pakistan and assessment of radiological hazards

The natural level of radioactivity in soil is one of the major causes of external gamma rays exposure. It was considered imperative to measure gamma-ray activity concentrations due to naturally occurring, potentially hazardous radionuclides from 232Th, 226Ra and 40K in soil samples from Punjab, the most populated province of Pakistan. The activity concentrations were measured in soil samples collected from all 34 district headquarters of Punjab province using a P-type coaxial high purity germanium (HPGe)-based gamma-ray spectrometer having a relative efficiency of 60%. The mean activity concentrations for 232Th, 226Ra and 40K were found to be 41 +/- 8, 35 +/- 7 and 615 +/- 143 Bq kg(-1), respectively in soil samples from all 34 district headquarters of Punjab. The mean values of radium equivalent index (Ra(eq)) and total annual external gamma radiation dose were found to be 141 +/- 27 Bq kg(-1)and 0.38 mSv, respectively. Since these estimated radiological impact assessment factors are lower than the recommended values there seems to be no potential radiological health hazard associated with the soils from the district headquarters in the Punjab province of Pakistan. Geological studies show that most of the soils in Punjab have developed on the extensive fluviatile deposits of five rivers and a stable ratio of natural activity concentrations is observed in soil samples of the areas under study.     

Measurement of natural radioactivity and assessment of associated radiation hazards in soil around Baoji second coal-fired thermal power plant, China

Activity concentrations of natural radionuclides (226)Ra, (232)Th and (40)K in soil around Baoji Second coal-fired thermal power plant of China were determined using gamma ray spectrometry. The mean activity concentrations of (226)Ra, (232)Th and (40)K in soil were found to be 40.3 ± 3.5, 59.6 ± 3.1 and 751.2 ± 12.4 Bq kg(-1), respectively, which are all higher than the corresponding average values in Shaanxi, Chinese and world soil. The radium equivalent activity (Ra(eq)), the air absorbed dose rate (D), the annual effective dose (E), the external hazard index (H(ex)) and internal hazard index (H(in)) were evaluated and compared with the internationally reported or reference values. All the soil samples have Ra(eq) lower than the limit of 370 Bq kg(-1) and H(ex) and H(in) less than unity. The overall mean outdoor terrestrial gamma air absorbed dose rate is ～86.6 ± 3.4 nGy h(-1) and the corresponding outdoor annual effective dose is 0.106 ± 0.004 mSv, which is higher than the worldwide average (0.07 mSv y(-1)) for outdoor's annual effective dose.     

Study on radionuclides in granite quarries of Bangalore rural district, Karnataka, India

Studies on natural radiation levels and radionuclides were carried out extensively in the environment of granite quarries of Kanakapura, Ramanagara Taluks and Bidadi Hobli in Bangalore rural District and Bangalore city. The indoor and outdoor gamma exposure rate in air was measured using an environmental dosemeter, and it is converted into absorbed dose using suitable conversion factor. The activity concentrations of natural radionuclides in rock samples and also in soil samples were measured using an HPGe gamma-ray spectrometer. The results reveal that the activity concentrations of (226)Ra, (232)Th and (40)K in rocks are found to be vary from 32.2 to 163.6, 128.3 to 548.6 and 757.4 to 1418.4 Bq kg(-1), respectively, with corresponding arithmetic mean values of 93.2, 306.2 and 1074.4 Bq kg(-1). Activity concentrations of (226)Ra, (232)Th and (40)K in soil samples were found to vary from 32.4 to 55.2, 39.9 to 214.3 and 485.4 to 1150.2 Bq kg(-1), respectively, with corresponding arithmetic mean values of 40.7, 93.1 and 750.4 Bq kg(-1). The average activity levels of all these radionuclides are above the global average. This is consistent with the geological and geo-chemical significance of the rocks of the area under investigation. The results of these systematic investigations are discussed in detail and compared with the literature values represented for other environments.     

Measurement of natural radioactivity and dose rate assessment of terrestrial gamma radiation in the soil of southern Punjab, Pakistan

Activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in soil samples collected from the most populous area of southern Punjab of Pakistan have been measured by gamma-ray spectrometry. The measured activity concentrations for these radionuclides are compared with the reported data from different other countries and it is found that measured activity concentrations are comparable with the worldwide measured average values reported by the UNSCEAR. Subsequently assessed radiological effects show that the mean radium equivalent activity (Ra(eq)) is 96.7 +/- 15.2 Bq kg(-1) and air absorbed dose rate (D) is 46.1 +/- 7.3 nGy h(-1). The values of internal and external radiation hazard indices are found to be less than unity. The annual effective radiation dose is calculated to be 0.28 +/- 0.05 mSv, which is well below the limit of 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection, for the general public.     

Natural radionuclides content and associated dose rates in fine-grained sediments from Patras-Rion sub-basins, Greece

The activity concentrations of the natural radionuclides (238)U, (226)Ra, (232)Th and (40)K were measured in soil samples collected from the Patras-Rion sub-basins (Southern Greece) and were found to be 28, 27, 30 and 483 Bq kg(-1), respectively. These values compare well with the average Greek and worldwide values for crustal soil and sedimentary rocks. The mean (226)Ra/(238)U activity ratio was close to 1, implying secular radioactive equilibrium in the uranium series. All soil samples have Ra(eq) values lower than the limit of 370 Bq kg(-1), indicating their safe use in brick production. The average annual terrestrial absorbed dose rate in air was 51±14 nGy h(-1), and the average annual effective dose 0.06±0.02 mSv y(-1), which is consistent with the average worldwide exposure to external terrestrial radiation outdoors (0.07 mSv y(-1)). Non-significant differences between soils with different age and depositional environments were found, which could be attributed to a common source of sediments.     

Measurement of natural radioactivity in beach sands from Rizhao bathing beach, China

The natural radioactivity of (226)Ra, (232)Th and (40)K was determined for beach sand samples collected from Rizhao bathing beach, China, using gamma ray spectrometry. The measured activity in beach sand ranges from 7.6 to 17.2, 7.8 to 25.1 and 883.4 to 1313.6 Bq kg(-1) for (226)Ra, (232)Th and (40)K with mean values of 12.0, 15.2 and 1079.2 Bq kg(-1), respectively. The activity concentrations of (226)Ra and (232)Th in beach sands are lower, while (40)K is higher than the world average. The radium equivalent activity in all beach sand samples is lower than the safe limit set in the OECD report (370 Bq kg(-1)). The values of the external hazard index are less than unity. The mean outdoor air absorbed dose rate is 59.8 nGy h(-1) and the corresponding outdoor effective dose rate is 0.073 mSv y(-1).     

Activity concentrations and mean annual effective dose of foodstuffs on the island of Tenerife, Spain

A total of 26 different food types and 12 elaborated diets were analysed by low-level gamma spectrometry to measure their content of 238U(234Th), 228Ra(228Ac), 226Ra(214Pb), 210Pb, 137Cs and 40K. The concentrations of these radionuclides measured in some imported foodstuffs were compared with those measured in some locally produced ones. Moreover, the concentrations found in the analysed foodstuffs and composite diets were compared with the data available in literature from other locations, such as Egypt, Brazil, Poland and Hong Kong. 40K contributed highest to the daily dose produced by the intake of comestibles. The largest 40K concentrations were measured in the chickpeas and beans with 380 +/- 30 and 380 +/- 20 Bq kg(-1) fresh weights, respectively. The artificial radionuclide 137Cs was measured only above detection limits in the potatoes and sweet potatoes. A mean annual effective dose of 362 microSv with a standard deviation of 110 microSv was calculated from the composite diets.     

Study on external exposure doses from terrestrial radioactivity in Southern Vietnam

This paper presents the radioactivity concentrations of 226Ra, 232Th and 40K for 106 samples of surface soil collected in Southern Vietnam. The mean values of mass activity of radionuclides 226Ra, 232Th and 40K for Southern Vietnam are 28.6, 50.7 and 292.6 Bq kg(-1), respectively, which lead to the population-weighted absorbed dose rate of 54.5 nGy h(-1). The average annual effective doses outdoors, indoors and in total of Southern Vietnam are estimated to be 0.067, 0.374 and 0.441 mSv, respectively. The radium equivalent activity and the external hazard index of soil in Southern Vietnam are in the range 23.2-254.1 Bq kg(-1) and 0.06-0.69, respectively.     

Natural radioactivity contents in tobacco and radiation dose induced from smoking

One of the causative factors for cancer-inducing mechanisms in humans is radioactive elements present in tobacco leaves used in the manufacture of cigarettes. Smoking of tobacco and its products increases the internal intake and radiation dose due to naturally occurring radionuclides that are considered to be one of the most significant causes of lung cancer. In this work, different commercial types of cigarettes, cigar and moassel were collected from market. Naturally occurring radionuclides (226)Ra and (214)Bi ((238)U series), (228)Ac and (228)Ra ((232)Th series), (40)K and man-made (137)Cs were measured in tobacco using gamma-ray spectrometer. Results show that the average concentrations of (238)U, (232)Th and (40)K were 4.564, 3.940 and 1289.53 Bq kg(-1), respectively. This reflects their origin from the soil by root uptake and fertilisers used in the cultivation of tobacco plants. Concentration of (137)Cs was 0.348 Bq kg(-1) due to root uptake or deposition onto the leaf foliage. For smokers, the annual effective dose due to inhalation of (238)U varied from 49.35 to 139.40 μSv(-1) (average 104.27 μSv y(-1)), while of (232)Th from 23.86 to 111.06 μSv y(-1) (average 65.52 μSv y(-1)). The annual effective dose resulting from (137)Cs was varied from 10.96 to 24.01 nSv y(-1) (average 19.41 nSv y(-1)).     

Investigations on the activity concentrations of 238U, 226RA, 228RA, 210PB and 40K in Jordan phosphogypsum and fertilizers

The activity concentrations of naturally occurring radionuclides ((238)U, (226)Ra, (228)Ra, (210)Pb and (40)K) in Jordanian phosphate ore, fertilizer material and phosphogypsum piles were investigated. The results show the partitioning of radionuclides in fertilizer products and phosphogypsum piles. The outcome of this study will enrich the Jordanian radiological map database, and will be useful for an estimation of the radiological impact of this industrial complex on the immediate environment. The activity concentration of (210)Pb was found to vary from 95 +/- 8 to 129 +/- 8 Bq kg(-1) with a mean value of 111 +/- 14 Bq kg(-1) in fertilizer samples, and from 364 +/- 8 to 428 +/- 10 Bq kg(-1) with a mean value of 391 +/- 30 Bq kg(-1) in phosphogypsum samples; while in phosphate wet rock samples, it was found to vary between 621 +/- 9 and 637 +/- 10 Bq kg(-1), with a mean value of 628 +/- 7 Bq kg(-1). The activity concentration of (226)Ra in fertilizer samples (between 31 +/- 4 and 42 +/- 5 Bq kg(-1) with a mean value of 37 +/- 6 Bq kg(-1)) was found to be much smaller than the activity concentration of (226)Ra in phosphogypsum samples (between 302 +/- 8 and 442 +/- 8 Bq kg(-1) with a mean value of 376 +/- 62 Bq kg(-1)). In contrast, the activity concentration of (238)U in fertilizer samples (between 1011 +/- 13 and 1061 +/- 14 Bq kg(-1) with a mean value of 1033 +/- 22 Bq kg(-1)) was found to be much higher than the activity concentration of (238)U in phosphogypsum samples (between 14 +/- 5 and 37 +/- 7 Bq kg(-1) with a mean value of 22 +/- 11 Bq kg(-1)). This indicates that (210)Pb and (226)Ra show similar behaviour, and are concentrated in phosphogypsum piles. In addition, both isotopes enhanced the activity concentration in phosphogypsum piles, while (238)U enhanced the activity concentration in the fertilizer. Due to the radioactivity released from the phosphate rock processing plants into the environment, the highest collective dose commitment for the lungs was found to be 1.02 person nGy t(-1). Lung tissue also shows the highest effect due the presence of (226)Ra in the radioactive cloud (0.087 person nGy t(-1)).     

Natural radioactivity in tap waters of Eastern Black Sea region of Turkey

In this study, the activity concentrations of some radionuclides in tap water samples of the Eastern Black Sea region of Turkey were measured. The activity concentrations of radionuclides (214)Pb, (214)Bi, (40)K, (226)Ra and (137)Cs were determined using high resolution gamma ray spectrometry. Furthermore, (222)Rn activity concentrations in tap water samples were measured using Liquid Scintillation Counting. The mean specific activities of (214)Pb, (214)Bi, (226)Ra, (40)K, (137)Cs and (222)Rn in tap water samples were 6.73, 6, 19.16, 168.57, 5.45 mBq l(-1) and 10.82 Bq l(-1), respectively. These values are comparable with concentrations reported for other countries. The effective doses were determined due to intake of these radionuclides as a consequence of direct consumption of tap water samples. The estimated effective doses were 6.878 x 10(-4) microSv y(-1) for (214)Pb, 4.800 x 10(-4) microSv y(-1) for (214)Bi, 3.916 microSv y(-1) for (226)Ra, 0.763 microSv y(-1) for (40)K, 0.052 microSv y(-1) for (137)Cs and 5.848 microSv y(-1) for (222)Rn.     

Radiological significance of cement used in building construction in Turkey

The activity concentration of (226)Ra, (232)Th and (40)K in seven cement types from different factories and grinding plants were measured using a gamma ray spectrometry with HPGe detector. The average activity concentrations observed in the studied cement samples (all from 141 samples) were 40.0 +/- 27.1, 28.0 +/- 20.9 and 248.3 +/- 95.0 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The radium equivalent activity (Ra(eq)), the representative level index, the indoor absorbed dose rate and the corresponding annual effective dose were estimated for the potential radiological hazard of the cement. The Ra(eq) values were compared with the corresponding values for cement of different countries. The mean indoor absorbed dose rate (87.4 +/- 48.5 nGy h(-1)) is slightly higher than the population-weighted average of 84 nGy h(-1), whereas the corresponding effective dose rate (0.4 +/- 0.2 mSv y(-1)) is lower than the dose criterion of 1 mSv y(-1). The obtained results indicate no significant radiological hazards arise from using Turkish cement in building construction.     

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.     

Vertical distributions of 137Cs, 40K, 232Th and 226Ra in soil samples from Istanbul and its environs, Turkey

Determining the distribution of natural and artificial radionuclides in soil profiles as well as the surface layer of the soil is necessary due to the fact that radionuclides can enter the food chain from deeper soil layers and also contaminate ground water. In the current study, the activity-depth profiles of (137)Cs were determined in soil samples from 20 sites in and around the city of Istanbul. Naturally occurring radionuclides were determined at 12 of the locations. Uncultivated soil samples were taken in six horizontal layers at each location. Activity concentrations were measured with a gamma spectrometer. The impacts of texture, organic matter and pH of the soil on the vertical distribution of the radionuclides were also studied. The average and standard deviations of (137)Cs and (40)K activity concentrations in soil at a depth of 5 cm were found to be 16.46±14.71 and 450.2±239.1 Bq kg(-1), respectively. The activity concentrations of (40)K, (232)Th and (226)Ra were distributed uniformly with regard to soil depth. The depth distribution of (137)Cs generally fitted a linear function. The study revealed that >20 y after the Chernobyl disaster of 1986, 55 % of (137)Cs still remains in the upper 10 cm of soil in the Istanbul environment.     

Radioactivity level in Chinese building ceramic tile

The activity concentrations of (226)Ra, (232)Th and (40)K have been determined by gamma ray spectrometry. The concentrations of (226)Ra, (232)Th and (40)K range from 158.3 to 1087.6, 91.7 to 1218.4, and 473.8 to 1031.3 Bq kg(-1) for glaze, and from 63.5 to 131.4, 55.4 to 106.5, and 386.7 to 866.8 Bq kg(-1) for ceramic tile, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and with the typical world values. The radium equivalent activities (Ra(eq)), external hazard index (H(ex)) and internal hazard index (H(in)) associated with the radionuclides were calculated. The Ra(eq) values of all ceramic tiles are lower than the limit of 370 Bq kg(-1). The values of H(ex) and H(in) calculated according to the Chinese criterion for ceramic tiles are less than unity. The Ra(eq) value for the glaze of glazed tile collected from some areas are >370 Bq kg(-1).