Assessment of health hazard due to natural radioactivity in Kluang District,Johor, Malaysia

The radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate and annual effective dose, which are 144 nGy h^?1, 0.891 mSv y^?1 and 178 μSv, respectively. A high-purity germanium detector was used to determine the activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K in soil samples. The results of the gamma spectrometry of the soil samples show radioactivity concentration ranges from 19±1 to 405±13 Bq kg^?1 with a mean value of 137±5 Bq kg^?1 for ²³²Th, from 21±2 to 268±9 Bq kg^?1with a mean value of 78±3 Bq kg^?1 for ²²⁶Ra and from 23±9 to 1268±58 Bq kg^?1 with a mean value of 207±13 Bq kg^?1 for ⁴⁰K. Radium equivalent activity (Ra_eq) and external hazard index (H_ex) were 290 Bq kg^?1 and 0.784, respectively, which were safe for the population. The mean lifetime dose and lifetime cancer risk for each person living in the area with average lifetime (70 y) were 12.46 mSv and 7.25×10^?4 Sv year, respectively. The results were compared with values given in United Nations Scientific Committee on the Effects of Atomic Radiation 2000.     

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.     

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.     

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 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.     

Radioactivity in Montenegro beach sands and assessment of the corresponding environmental risk

Activity concentrations of the naturally occurring radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K and anthropogenic ¹³⁷Cs in sand samples collected from 20 renowned beaches on the Coast of Montenegro have been determined using an HPGe (high purity Ge spectrometer). The average activity concentrations were found to be 7.4, 5.2, 97.3 and 0.5 Bq kg^?1, respectively. For all sand samples, the radium equivalent activity has been evaluated and found to be lower than the limit of 370 Bq kg^?1. External and internal hazard indices were less than unity. The gonadal dose equivalent was estimated to be on average 75 μSv y^?1, which is about four times lower than the global average for soil (0.3 mSv y^?1). Calculated values of absorbed dose rates showed the range from 3.1 to 28 nGy h^?1, which is below the world median of average values (57 nGy h^?1). The effective dose rate in the range from 3.8 to 34.4 μSv y^?1 was significantly below the recommended limit value for the public (1 mSv y^?1). The highest dose rate was found for the Velika Plaza locality, which also showed heavy metal contents (As, B, Cd, Hg, Cr, Cu, Mn, Ni, Pb, Zn and Ba) significantly higher than in the sand from Jaz, a locality with one of the lowest dose rates.     

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.     

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.     

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.     

Determination of 226Ra, 232Th and 40K in teeth by use of gamma spectroscopy

This study entails the measurement of the specific activity of natural radionuclides (²²⁶Ra, ⁴⁰K and ²³²Th) in 18 tooth samples obtained from the clinic of the Universiti Sains Malaysia (USM), Penang, by using an HPGe detector. The specific activity of ²²⁶Ra, ⁴⁰K and ²³²Th was measured to estimate the hazard index of the radionuclides, radium equivalent activities (Ra_eq), external, internal hazard indices (H_ex, H_in), and absorbed dose (D_out, D_in). The maximum values of concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in the tooth samples were found to be 60.82, 60.29 and 594.22?Bq kg^?1, respectively. Maximum values of Ra_eq, H_ex, H_in, D_out and D_in were found to be 192.78?Bq kg^?1, 0.520, 0.685, 89.29 and 169.81?nGy h^–1, Iγ and Iα as 0.702 and 0.304, respectively. The results were lower than the average world value (UNSCEAR). In addition, a strong correlation was found between the concentrations of ²²⁶Ra and Ra_eq, between energy and net area, as well as between radionuclides (²²⁶Ra, ⁴⁰K and ²³²Th) in tooth samples and age of volunteers. This study showed that the concentrations and hazard indices of tooth samples are below the recommended safe levels; therefore, the study area is considered safe in terms of radiological health hazards.     

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.     

Radium equivalent and annual effective dose from geological samples from Pedra – Pernambuco – Brazil

The natural radioactivity of an uranium-anomalous area utilized for agricultural activities in Pedra, Brazil, was monitored. For this, samples from the granite and calcium-silicate amphibole rocks underlying this area and also from samples of the soil derived from these rocks were collected and analyzed by high-resolution gamma spectrometry. The equivalent radium (Ra_eq) was used as a reference for estimating the rate of the effective equivalent dose. The average, minimum and maximum values for the samples were of 319.2 Bq kg^?1 (91.1–758.5 Bq kg^?1) for soil; 327.5 Bq kg^?1 (36.3–1624.0 Bq kg^?1) for granitic rocks and 70,124.5 Bq kg^?1 (16,979.6–147,159.0 Bq kg^?1) for the calcium-silicate amphibole rocks. An estimation of the external exposition was carried out based on the calculation of the parameters obtained.     

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).     

Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)

Concentration of ²²²Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measurements were performed by an AlphaGUARD radon gas analyser. The average radon concentrations were found to vary from 0.39±0.02 to 12.73±0.39 Bq l^?1 for natural springs and from 0.36±0.04 to 9.29±0.45 Bq l^?1 for tap water in spring, from 0.50±0.09 to 19.21±1.00 Bq l^?1 for natural springs and from 0.31±0.03 to 13.14±0.38 Bq l^?1 for tap water in summer. Furthermore, the results are compared with international recommendations and concentrations reported for other countries. Doses resulting from the consumption of these waters were calculated. The effective dose equivalents due to the intake of the ²²²Rn present in these waters are expected to range from 0.93 to 32.54 μSv y^?1 in summer and from 0.80 to 49.09 μSv y^?1 in spring.     

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).     

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.     

137Cs and 40K activity concentration measurements and elemental analysis in lichen samples collected from the Giresun province of northeastern Turkey

About 21 years after the Chernobyl accident, ¹³⁷Cs and ⁴⁰K activity concentration measurements using gamma-ray spectroscopy and elemental analysis using energy dispersive X-ray spectroscopy were performed in five different lichen species collected from the Giresun province of northeastern Turkey. Being a symbiosis of algae and fungi, lichens are mostly used for environmental measurements since the fungal partner is responsible for the uptake of necessary nutrients or harmful substances, such as heavy metals of radionuclides. The gamma activity results showed that ¹³⁷Cs, an artificial radionuclide released from the Chernobyl power plant accident, is still eminent in the environment of the province. The mean activity concentrations of ¹³⁷Cs and ⁴⁰K ranged from 24 to 254 with the mean value of 102 Bq kg^?1 and from 345 to 2103 with the mean value of 1143 Bq kg^?1 in dry weight. The results of the elemental analyses showed potassium, calcium, titanium, iron, tin, and barium in different concentrations.     

Assessment of natural radioactivity in rice and their associated population dose estimation

ABSTRACT

The concentration of natural radioactivity in rice is an important parameter for the determination of population exposure by the ingestion of natural radionuclides during habitual consumption of food. All types of food including rice contain a detectable amount of natural radioactivity which successively relocate into the human body via the ingestion pathway. Rice is the main cultivated crop in Bangladesh and most of the Bangladeshi people consume rice as their staple food. Hence, studies on the evaluation of natural radioactivity in rice have been performed by gamma-ray spectrometry using High Purity Germanium (HPGe) detector in order to estimate various radiation hazards due to rice consumption. The average activity levels of natural radionuclides ²²⁶Ra, ²²⁸Ra and ⁴⁰K in the rice samples were 1.09?±?0.31, 0.17?±?0.21 and 4.70?±?1.59?Bq?kg^?1, respectively. The estimated effective doses for the respective radionuclides caused by the rice consumption were 43.69, 16.39 and 4.15?µSv?y^?1, respectively which was below the UNSCEAR compiled value. The calculated excess lifetime cancer risk (ELCR) values via rice consumption were found below the acceptable limit of 0.29?×?10^?3 for radiological risk.