Transfer of radioactivity from soil to vegetation in Rechna Doab,Pakistan

In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of ²²⁶Ra, ²³²Th/²²⁸Ac and ⁴⁰K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of ²²⁶Ra, ²³²Th/²²⁸Ac and ⁴⁰K in soil were found to be 46.8±6.2 (36.0–57.6), 61.4±5.9 (48.2–73.2) and 644.8±73.9 (537.7–868.4) Bq kg^?1 (dry mass), respectively, and those in vegetation were 2.74±1.70 (1.00–6.39), 2.24±0.59 (1.56–2.61) and 172.72±113.37 (53.14–469.24) Bq kg^?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of ²²⁶Ra, ²²⁸Ac and ⁴⁰K were 0.06±0.03 (0.02–0.14), 0.04±0.01 (0.03–0.04) and 0.26±0.16 (0.09–0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h^?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h^?1. The total annual effective dose to the general public from the vegetation was found to be (0.02–0.16) mSv, which is below the recommended limit value of 1 mSv y^?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment.     

Radioactivity concentrations in topsoil samples from the Thrace region of Turkey and assessment of radiological hazard

The activity concentrations of gamma emitting radionuclides were measured in surface soil samples from the Thrace region. ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs activities and physico-chemical parameters of the soil samples were determined in samples collected from 73 sampling stations. Radionuclide concentrations measured were compared with those found in the samples from other locations of Turkey and from different countries. The average activity concentrations of ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were found to be 24.71 ± 8.79, 22.30 ± 7.93, 32.09±12.44, 509.00±160.05, 32.74±29.24 Bq kg^?1, respectively. The mean value of the annual effective dose equivalent from the outdoor terrestrial gamma radiation was calculated as 57.2 μ Sv.     

Radon survey and soil gamma doses in primary schools of Batman,Turkey

A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual ²²²Rn activity in the surveyed area was found to be 49 Bq m^?3 (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m^?3. The estimated annual effective doses are less than the recommended action level (3–10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values.     

Natural radionuclide concentrations in soils around Baoji coal-fired power plant,China

Radionuclides are released together with fly ash from the coal-fired power plant and thus add to the natural radiation. Fifty soil samples were collected around the Baoji coal-fired power plant from 25 locations and the natural radionuclide concentrations were determined by a gamma ray spectrometric system. The results show that the activity concentrations in soil samples range from 12.54 to 40.18 Bq kg^?1, 38.02 to 72.55 Bq kg^?1 and 498.02 to 1126.98 Bq kg^?1 for ²²⁶Ra, ²³²Th and ⁴⁰K with the mean values of 27.35, 52.66 and 764.72 Bq kg^?1, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Ra_eq), the absorbed dose rate (D) and the annual effective dose rate have been calculated and compared with the internationally approved values. The radium equivalent activity in all the soil samples is lower than the safe limit set in the Organization for Economic Cooperation and Development report (370 Bq kg^?1). The average value of the calculated dose rates is higher than the global average value 55 nGy h^?1, and the calculated annual effective dose rate is significantly lower than the average annual external effective dose rate (460 μSv y^?1) of the normal background radiation.     

Measurement of radionuclides and absorbed dose rates in soil samples of Peshawar,Pakistan, using gamma ray spectrometry

The analysis of gamma-emitting radionuclides in nature, i.e. ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, has been carried out in soil samples collected from Peshawar University Campus and surrounding areas using a high purity germanium detector coupled with a computer-based high-resolution multichannel analyser. The activity concentrations in soil ranged from 30.20±0.65 to 61.90±0.95, 50.10±0.54 to 102.80±1.04, 373.60±4.56 to 1082±11.38 and 9.50±0.11 to 46.60±0.42 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, with a mean value of 45±7.70, 67±12.50, 878±180 and 19±9.20 Bq kg^?1, respectively. The radium equivalent activity, internal and external hazard indices have mean values of 203.40±29.40 Bq kg^?1, 0.56 and 0.68, respectively. The mean values of outdoor and indoor absorbed dose rates in air and the annual effective dose equivalents were found to be 106.50 and 128 nGy h^?1 and 0.19 and 0.54 mSv y^?1, respectively. In the present study, ⁴⁰K was the major radionuclide present in soil samples. The presence of ¹³⁷Cs indicates that this area also received some fallout from the nuclear accident of the Chernobyl power plant in 1986. The activity concentrations of radionuclides found in soil samples during the current investigation were nominal. Therefore, they are not associated with any potential source of health hazard to the public.     

Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts

Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were measured by using γ-ray spectrometry. The mean activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg^?1 for ²²⁶Ra, 83±5, 71±7 and 162±23 Bq kg^?1 for ²³²Th and 513±10, 493±20 and 681±28 Bq kg^?1 for ⁴⁰K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.     

Radioactive analysis and radiological hazards in different types of Egyptian cement

Studies of the natural γ-emitting radionuclides in different types of cements manufactured by different companies in Egypt (e.g. Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan Ltd.) have been done to determine their natural levels of radioactivity using a high-purity germanium detector (HPGe). Knowledge of radioactivity present in cement materials enables one to assess any possible radiological risks to human health. The results show that the highest mean values of ²²⁶Ra and ²³²Th activity are 234.01±20.12 and 46.56±4.65 Bq kg^?1, respectively, measured in cement sample ‘Iron’ from Helwan company (HI). The corresponding value of ⁴⁰K is 333.53±26.68 Bq kg^?1 measured in cement sample ‘Karnak’ from Helwan company (HK). For ¹³⁷Cs, this value is 3.27±0.31 Bq kg^?1 measured in cement sample (HI). The average concentrations of measured radionuclides in the different cement samples are 72.21±6.39, 24.98±2.24, 134.49±10.45, and 0.58±0.08 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries. Radium equivalent (Ra_eq) activities and different hazard indices were calculated to assess the radiation hazard. Iron HI cement sample shows a higher Ra_eq activity of 311.91±31.10 Bq kg^?1. Calculations of absorbed doses in nGy h^?1 show that the Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan company have higher activities than the permissible level (80 nGy h^?1). On the basis of the external hazard index (H _ex), Ra_eq activities, and annual effective dose rates for organs (H _organ), the natural radioactivity of cement samples is not greater than the recommended values in the established standards and hence safe for use in building constructions and therefore for inhabitants.     

Natural radioactivity measurements in Pahang State,Malaysia

This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176?±?5 nGy h^?1. Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K are 110?±?3, 151?±?5 and 542?±?51 Bq kg^?1, respectively.²²⁶Ra and ²³²Th concentrations were found to be three times the world average, while that of ⁴⁰K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for ²²⁶Ra (215?±?6 Bq kg^?1), ²³²Th (384?±?12 Bq kg^?1) and ⁴⁰K (1564?±?153 Bq kg^?1). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg^?1 and the unity value, respectively.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.     

Evaluation of some pollutant levels in environmental samples collected from the area of the new campus of Taif University

The levels of radioactivity and heavy metals in soil, plant and groundwater samples collected from the area of the new campus of Taif University, Saudi Arabia, and its neighbouring areas have been determined. High-resolution gamma-ray spectroscopy was used for radioactivity measurements, and inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of heavy metals. The means of ²²⁶Ra, ²²⁸Ra and ⁴⁰K concentrations in water samples collected from four wells were found to be 0.13±0.03, 0.05±0.03 and 1.3±0.5 Bq l^?1, respectively. The means of ²³⁸U, ²²⁶Ra, ²²⁸Ra (²³²Th for soil samples) and ⁴⁰K concentrations in wild plant and soil samples were found to be 3.7±4.1, 8.8±11.6, 3.8±2.9 and 1025±685, and 8.6±3.4, 12.8±3.4, 16.6±7.1 and 618±82 Bq kg^?1 dry weight (DW), respectively. The ¹³⁷Cs of artificial origin was also detected in soil samples with a mean concentration of 3.8±2.2 Bq kg^?1 DW. Evaluating the results, it can be concluded that the concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K in soil samples fall within the world average. Furthermore, 19 trace and major elements in groundwater samples and 22 elements in soil and plant samples were determined. The sampling locations of soil can be classified into three groups (relatively high, medium and low polluted) according to their calculated metal pollution index using the contents of trace and major elements. A cluster analysis of the contents of radioactivity and trace element contents in soil samples shows the presence of two main distinct clusters of sampling locations.     

Radioactivity of sand,groundwater and wild plants in northeast Sinai,Egypt

The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km² in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among ²³⁸U, ²³⁴Th, and ²²⁶Ra isotopes and low significant correlations between the concentrations of ²³⁸U-series and ²³²Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. The range of concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in water samples collected from five wells were<0.4–0.16,<0.4–0.13, and<0.15–1.62 Bq l^?1, respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h^?1. The Ra_eq activities of the sands are lower than the recommended maximum value of 370 Bq kg^?1 criterion limit for building materials.     

The determination of concentrations of radioisotopes in some granite samples in Turkey and their radiation hazards

The primordial radionuclides activity concentrations (²²⁶Ra, ⁴⁰K and ²³²Th) are measured in some granite samples in this study. The collected granite materials are analyzed with NaI(Tl) gamma-ray spectrometry. The specific activity of ²²⁶Ra, ²³²Th and ⁴⁰K values are in range 2.60?±?0.10 to 178.9?±?0.6?Bq?kg^?1, 1.46?±?0.10 to 162.50?±?0.75?Bq?kg^?1 and 19.8?±?0.3 to 579.7?±?2.8?Bq?kg^?1 respectively. The radium’s equivalent activity, annual effective dose, absorbed dose rate, hazard index, radioactivity level index, activity utilization’s index and exposure rate are calculated for determination of radiological risk. The concentration of ²²⁶Ra (in the 71.4% of samples), ²³²Th (in the 71.4% of samples) and ⁴⁰K (in the 14.3% of samples) in the granite samples are higher than average radioactivity concentrations of this radio-isotopes defined by ICRP (35.0, 30.0 and 400.0?Bq?kg^?1, respectively).     

Assessment of natural radionuclides and their radiological hazards in commercial granite produced in Xinjiang,China

ABSTRACT

The specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K of 26 samples of granite produced in Xinjiang of China were measured by a high-purity germanium detector, and their radiological hazards of radium equivalent, external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index were evaluated. The results indicate that the overall average specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K obtained in the investigated samples are below the world’s average granite values. The average radium equivalent is within the recommended limit of 370?Bq?kg^?1. The results obtained further show that the mean values of external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index are 0.65, 0.77, 111.7?nGy?h^?1, 0.55 mSv?y^?1, 0.89 and 0.23, respectively. These mean values established that radiological hazards are also found to be below the international recommended values. The results are compared with granite samples from other countries or China-Taiwan province. It can be noticed that the specific activity values of granite samples produced in China are lower or similar to that of other countries or China-Taiwan province, however there are higher specific activity values for ²²⁶Ra and ²³²Th in individual samples, which need to provide proper radiation monitoring before use considering the long term health effect.     

Appraisal of radioactivity and associated radiation hazards in sand samples of four rivers of Punjab province,Pakistan

Natural and anthropogenic radioactivity of sand and water samples collected from the four big rivers of Punjab province, Pakistan, was measured using a high-purity germanium detector coupled with a high resolution multichannel analyser. The average concentration of the naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in all the sand samples from the rivers Jhelum, Chenab, Ravi and Indus was found to be 22±0.6, 36±1 and 287±10 Bq?kg ^?1, respectively, while the concentration of the anthropogenic radionuclide ¹³⁷Cs was found to be below the minimum detectable activity, i.e. ～ 1.2 Bq?kg ^?1. All the sand samples have Ra_eq concentrations lower than the limit of 370 Bq?kg ^?1. Indoor (H _in) and outdoor (H _out) radiation hazard indices were calculated for the samples to assess the radiation hazards arising due to the use of this sand in construction, and were found to be less than unity in the study area. Calculated values of the absorbed dose rate were less than the typical world average value of 59 nGy?h ^?1, and the annual effective dose rate was also less than the typical world value of 70 μSv, except in the Indus river, in which it is slightly higher then the world average. Results show that the measured values are comparable with other global radioactivity measurements. None of the studied riverbeds was considered a radiological hazard, and their sand can be safely used in construction.     

Natural radioactivity and radiation hazards assessment of soil samples from the area of Tuzla and Lukavac,Bosnia and Herzegovina

The results of activity concentration measurements of natural occurring radioactive nuclides ²³⁸U, ²³⁵U, ²³²Th, ²²⁶Ra, and ⁴⁰K in surface soil samples collected in the area of cities Tuzla and Lukavac, northeast region of Bosnia and Herzegovina were presented. Soil sampling was conducted at the localities that are situated in the vicinity of industrial zones of these cities. The measured activity was in the range from (8?±?4) to (95?±?28) Bq kg^–1 for ²³⁸U, from (0.41?±?0.06) to (4.6?±?0.7) Bq kg^–1 for ²³⁵U, from (7?±?1) to (66?±?7) Bq kg^–1 for ²³²Th, from (6?±?1) to (55?±?6) Bq kg^–1 for ²²⁶Ra, and from (83?±?12) to (546?±?55) Bq kg^–1 for ⁴⁰K. In order to evaluate the radiological hazard of the natural radioactivity for people living near industrial zones, the absorbed dose rate, the annual effective dose and the radium equivalent activity have been calculated and compared with the internationally approved values.     

Radiometric analysis and radiological hazards of Chinese commercial marble

The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in commercial marble materials have been determined using a NaI(Tl) γ-ray spectrometer with a matrix-inversion-based spectral stripping technique. Knowledge of radioactivity present in marble materials enables one to assess any possible radiological risks to human health. The concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in Chinese commercial marble range from 8.4 to 157.4, 5.6 to 165.5 and 44.1 to 1352.7 Bq kg^?1, respectively. The natural radionuclide concentration varied with color and production site of commercial marble. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in white, gray, black, green and yellow marble samples are comparatively smaller than those in brown and red marble samples. The radium equivalent activity (Ra_eq), the external hazard index (H _ex), the internal hazard index (H _in) and the annual gonadal dose equivalent were also calculated and compared with the internationally recommended values. One type of brown commercial marble (TSB) of China does not satisfy the universal standards.     

The potential health hazard due to elevated radioactivity in old uranium mines in Dolina Białego,Tatra Mountains,Poland

Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jo?ef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bia?ego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m^?3. Also, very high gamma dose rates were observed (up to 5600 nSv h^?1). The maximum concentrations of natural radioactive elements (potassium ⁴⁰K, radium ²²⁶Ra, thorium ²³²Th) in rock samples amounted to 535, 2137, and 18 Bq kg^?1, respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h^?1 (for the lowest concentration) and 0.121 mSv h^?1 (for the highest concentration).     

Activity concentrations of 226Ra, 232Th, 40K and 137Cs radionuclides in Turkish medicinal herbs,their ingestion doses and cancer risks

Twenty-two medicinal herb samples, each representing a distinct species, were collected from Turkish markets and measured by the gamma spectrometric method. The activity concentration of ²²⁶Ra in medicinal herbs was found in the range of minimum detectable activity (MDA) and 15.1?±?2.2?Bqkg^?1. The activity concentration of ²³²Th ranged from MDA values to 3.5?±?0.8?Bqkg^?1. The activity concentration of ⁴⁰K varied between 50.0?±?16.8 and 1311.5?±?57.3?Bqkg^?1. All ¹³⁷Cs activity concentrations of medicinal herbs were found to have lower than MDA values. The bone surface dose, lower large intestine and colon doses were found to be 182.9, 18.8 and 18.7?µSvy^?1, respectively. The highest committed effective dose originated from the annual ingestion of 1?kg medicinal herb was calculated notably low as 9.0?µSv. The cancer risk of ingestion of medicinal herbs was found to be small enough to be neglected. The selected Turkish medicinal herbs are considered safe for human consumption.     

Radiological impacts of natural radioactivity from phosphogypsum piles in Huelva (Spain)

The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been measured by gamma spectroscopy in samples of soil collected from the different zones of around Huelva (Spain). The average activity concentrations of ²²⁶Ra (Bq kg^?1) in the active phosphogypsum (PG) stacks, unrestored and restored zones were 647, 573 and 83 respectively. The corresponding values for ²³²Th and ⁴⁰K (Bq kg^?1) were 8, 10 and 25 and 33, 47 and 225 respectively. As a measure of radiation hazard to the occupational workers and public, the Ra equivalent activities, representative level index and dose rates due to natural radionuclides at 1 m above the ground surface were estimated. The average of absorbed dose rates due to ²²⁶Ra, ²³²Th and ⁴⁰K (nGy/h) from active PG stacks, unrestored and restored zones are 284, 255 and 55.The calculated external γ-radiation average dose (mSv/y) received by the workers of the phosphogypsum piles are estimated to be 0.293, 0.262 and 0.057 which is far below the international agreed dose limit of 20 mSv/y (ICRP-60, 1990) for workers. Also, the radiation dose to a member of the public resulting from the use of PG is negligible compared to the average annual effective dose from natural sources (2.4 mSv/y).