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1.
Soil samples were collected from different localities of districts Jhelum, Chakwal, Rawalpindi and Attock, Punjab Province, Pakistan with an aim to measure naturally occurring radionuclides, namely 226Ra, 232Th, 40K and fallout 137Cs radionuclide using a P-type coaxial high purity germanium (HPGe) γ-ray spectrometer. Measured specific activities of 226Ra, 232Th and 40K in these soil samples ranged from 26.02 ± 7.11 to 93.54 ± 8.13 Bq kg−1, 29.34 ± 2.58 to 114.41 ± 2.80 Bq kg−1 and 348.15 ± 3.20 to 752.98 ± 4.20 Bq kg−1, respectively. Activity due to 137Cs was observed in some locations which ranged from 0.4 ± 0.2 to 7.8 ± 0.3 Bq kg−1. From the measured activity concentrations, radium equivalent activity concentrations were determined followed by calculations of mean absorbed dose rate and mean annual effective dose for the inhabitants of the studied area. The mean radium equivalent activity, internal and external hazard indices values came out to be 179.26 ± 11.93 Bq kg−1, 0.64 ± 0.05 and 0.48 ± 0.03, respectively. Indoors and outdoor average annual effective dose values were found to be 0.42 ± 0.03 and 0.10 ± 0.01 mSv, respectively. Present data have been compared with the published data for other parts of the world and found to be safe for public and environment.  相似文献   

2.
Radioactivity levels in soil samples, collected from mid Rechna interfluvial region, Pakistan have been estimated by using gamma ray spectrometric technique. 226Ra, 232Th, the primordial radionuclide 40K and the artificial radionuclide 137Cs have been measured in the soil of the study area. The mean radioactivity levels of 226Ra, 232Th, 40K and 137Cs were found to be 49.0 ± 1.6, 62.4 ± 3.2, 670.6 ± 33.9 and 3.5 ± 0.4 Bq kg−1 respectively. The mean radium equivalent activity (Raeq), outdoor radiation hazard index (H out), indoor radiation hazard index (H in) and terrestrial absorbed dose rate for the area under study were determined as 189.9 ± 8.8 Bq kg−1, 0.51, 0.65 and 70.1 nGy h−1 respectively. The annual effective dose to the public was estimated to be 0.43 mSv. The measured values are comparable with other global radioactivity measurements and are found to be safe for public and environment.  相似文献   

3.
We determined 137Cs concentrations in deep water samples of the subtropical gyre in the South Pacific collected during the BEAGLE2003 cruise. This was done at an underground facility to achieve extremely low background γ-spectrometry, and we, therefore, obtained reliable values of 137Cs activity in the deeper layers. 137Cs activity in the layers between 2000 and 4500 m ranged from 7 ± 4 mBq m−3 to 25 ± 11 mBq m−3. The inventory of 137Cs in the water column from 2000 m to the sea bottom was estimated to be 20 ± 8 Bq m−2 to 94 ± 41 Bq m−2 in this region.  相似文献   

4.
Gracilaria edulis, an edible red marine macro algae from three high background radiation areas (Arockiapuram, Kadiapattinam and Kurumpanai) on the southwest coast of Tamil Nadu, and one low background radiation area (Mandapam) on the southeast coast of Tamil Nadu, in India, were studied for variations in average gross alpha and beta radiation activities. Significant variations in average gross beta activities were observed while alpha activities showed only marginal variation. The average gross alpha activity was recorded high (61.51 Bq kg 1) during the post southwest monsoon season, while it recorded lowest (25.48 Bq kg 1) during the post northeast monsoon season. Average gross beta activity varied between seasons with the lowest level (211.55 Bq Kg−1) during post southwest monsoon season and the highest (413.33 Bq kg 1) during post northeast monsoon season. Among the four locations, the gross alpha activity was high (70.95 ± 26.74 Bq Kg−1) in Arockiapuram and low (18.74 ± 6.32 Bq Kg−1) in Mandapam, while the gross beta activity was high (442.25 ± 168.53 Bq Kg−1) in Kurumpanai and low (158.63 ± 34.37 Bq Kg−1) in Mandapam. Average gross alpha activity in G. edulis was found significantly varying in terms of locations, while average gross beta activity for the same species recorded significant seasonal variation.  相似文献   

5.
In this study the concentration of natural radionuclides has been investigated in soil and water of Karun river by using a high resolution (HPGe detector, n-type) γ-spectrometry. The concentrations range in water sample was 47.6 ± 5.6–130.8 ± 6.3, 0.0–23.4 ± 0.5 and 0–6.4 ± 2.0 Bq L−1 for 40K, 232Th and 226Ra respectively. For soil samples the concentration range of 275.7 ± 8.6–458.6 ± 6.8, 19.2 ± 5.35–41.1 ± 3.95 and 29.9 ± 1.53–50 ± 1.54 Bq kg−1 was obtained respectively for 40K, 232Th and 238U. 137Cs was also detected in some part of the region in soil samples. The mean concentration of 137Cs was 5.5 ± 0.6 Bq kg−1. The origin of this activity is unknown. The average absorbed dose rate in outdoor air at a height of 1 m above the ground was found to be 54.3 ± 3.7 nGy h−1. The results of this study indicate that the area has standard background radiation level.  相似文献   

6.
This work presents the results of 137Cs, 40K, 232Th and 238U concentration (Bq kg−1) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit of 0.9 Bq kg−1 for 137Cs and the highest only being 1.4 Bq kg−1. While, the concentration (Bq kg−1) ranges for the primordial radionuclides, 40K, 232Th and 238U were as follows: 12.2–211.7, <1.5–9.8 and <4.4–20.7, respectively. These concentration ranges for the primordial radionuclides can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated by nature. Finally, the concentration range of 137Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear weapons in the past.  相似文献   

7.
This paper presents the results of measurement of natural and fallout radioactivity in soil samples of Chamba and Dharamshala areas in Himachal Pradesh, India. Spatial distribution of 238U, 226Ra, 232Th, 40K, 137Cs was determined using High resolution gamma-ray spectrometry. The mean activity concentration in Chamba region due to 238U, 232Th, 40K and 137Cs was 32.3, 58.4, 588.3, and 10.9 Bq kg−1, respectively, whereas in Dharamshala it was 35.7, 61.3, 594.9, 10.0 Bq kg−1, respectively. Absorbed gamma dose rate (D) in air was calculated using appropriate dose conversion factors, which was varying from 45 to 103 nGy h−1. To control the radiation exposure due to natural radioactivity in soil, if it is used as building materials, radium equivalent activity (Raeq) and activity index were also evaluated. Radium equivalent activity calculated for the soil ranged from 95.5 to 234.2 Bq kg−1 with average of 171.0 Bq kg−1.The calculated Activity concentration index was ranged from 0.34 to 0.85 with an average value of 0.64. The natural and fallout radioactivity in soil of this region is comparable with Indian average and other parts of the world. The percentage contribution of 238U, 232Th and 40K and 137Cs to the average external gamma dose rate was 22, 46, 32, 2%, respectively. This shows that the dose contribution due to fallout radioactivity is negligible as compared to the natural radioactivity.  相似文献   

8.
The activity concentration of beryllium-7 (7Be), a naturally occurring cosmogenic radionuclide produced in the upper atmosphere, was measured in plants on the Loess plateau of China during the growing season of 2005. The 7Be mass activity concentration on July 27 ranged from 34.8 to 147.1 Bq kg−1 in herbaceous plants, from 47.6 to 116.1 Bq kg−1 in subshrubs, and from 15.7 to 56.8 Bq kg−1 in crop plants. The 7Be mass and areal activity concentrations of a mixture of herbaceous plants increased from 66.8 to 288.7 Bq kg−1 and from 0.7 to 46.5 Bq m−2, respectively, during the growing season. On an areal basis, the fraction of 7Be in plants in the soil–plant system increased from 0.4 to 8.4% during the growing season. Positive linear correlations were found between the increases of 7Be mass and areal activity concentrations in the inter-sampling intervals and the amount of precipitation.  相似文献   

9.
The naturally occurring radioisotopes such as 238U, 232Th and 40K in the silt samples collected from Moticher lake, Gujarat were evaluated. The activity of 238U, 232Th and 40K was found to be 4.4-9.7 Bq kg−1 with a mean 6.4 ± 1.3 Bq kg−1, 10.5–21.2 Bq kg−1 with a mean 15.6 ± 2.5 Bq kg−1 and 102–231 Bq kg−1 with a mean 160 ± 40 Bq kg−1, respectively. The depth profile study could not reveal any significant vertical correlation on radioactivity levels of 238U, 232Th and 40K. Radium equivalent activity (Raeq), external hazard index (H ex) and internal hazard index (H int) were calculated by using the activity of 238U or 226Ra, 232Th and 40K in silt samples. Annual Effective Dose Equivalent (AEDE) level in Moticher silt was found to be 24.8 ± 5.0 μSv year−1, which is much lower than the worldwide average value. The relative contribution to dose due to 238U and 232Th series were found to be 14% and 53%, followed by the contribution of 33% due to 40K.  相似文献   

10.
In the present study, mussel (Mytilus galloprovincialis, Lamarck, 1819) and sediment samples were collected from the Bosphorus strait and the Golden Horn estuary in 2008 and 2009. Activity concentrations of 137Cs, 40K, 232Th and 238U were measured using a gamma spectrometer equipped with HPGe detector. Sediment samples were separated into <63 μm and >63 μm particle fractions. Analysis of radionuclides was carried out on these two fractions of sediment as well as the soft and shell tissues of mussels. Ranges of radioactivity concentrations in the soft parts of mussels were as follows: 137Cs, 0.86–2.43; 40K: 261.1–496.7; 232Th: 0.49–3.58; and 238U: BDL (below detection limit)-1.38 Bq kg−1 in dry weight. Ranges of radioactivity concentrations in the <63 and >63 sediment fractions were as follows: 137Cs, 8.58–67.92 and 1.12–26.40, 40K, 341.4–683.0 and 281.9–662.2; 232Th, 10.97–20.16 and 7.18–19.18 and 238U, 13.97–27.25 and 6.41–18 Bq kg−1 in dry weight, respectively. The effect of some physical–chemical parameters on the radionuclide accumulation was also examined in the sediment samples. All data in the current study were compared with data in the literature.  相似文献   

11.
226Ra activity concentration in the mullet (Mugilidae) species Mugil cephalus whole individuals, and some organs (gills, gastrointestinal system, fins, muscle and bones), was measured by the γ-coincidence spectrometer PRIPYAT-2M. 226Ra transfer parameters [concentration factors (CFs)] from seawater, sediment and mud with detritus to fish tissues, and annual intake by humans consuming this fish species, have been estimated. Minimum detected radium activity concentration in whole M. cephalus individuals was found to be 0.89 ± 0.42 to 3.09 ± 0.41 Bq kg−1, with arithmetic mean of 1.65 ± 0.39 Bq kg−1. An average concentration in muscles is found to be 2.28 ± 0.84 Bq kg−1, in gills—5.02 ± 1.85 Bq kg−1, in gastrointestinal system—12.88 ± 1.71 Bq kg−1, and in bones—14.72 ± 3.75 Bq kg−1. No one fins showed radium activity above minimum detectable one. Annual intake of 226Ra by human consumers of this fish species is estimated to provide an effective dose of 0.006 mSv year−1. CFs for 226Ra indicating transfer from seawater to whole individuals ranged from 8.9 to 30.9, and those indicating transfer from the sediment and mud with detritus—from 0.11 to 0.39 and from 0.08 to 0.3, respectively. The seawater to bones CFs varied from 97.9 to 197.3, to gastrointestinal system—from 59 to 178.8, to gills—from 22.5 to 68.3, to muscles—from 17 to 30.8.  相似文献   

12.
The present work investigated the activity concentrations of natural radionuclides 226Ra, 232Th and 40K in beach sand samples along coastal Kerala including high background radiation area. The activity of 232Th ranges from below detectable level to 23029.9 Bq kg−1 with a mean value of 2660.2 Bq kg−1 for 0–10 cm depth interval. For 10–20 cm depth, the 232Th activity ranged from below detectable to 4452.2 Bq kg−1 with a mean value of 815.5 Bq kg−1. The variation of 226Ra activity with depth is parallel with the 232Th activity distribution in beach sand. Its activity varied from below detectable to 5169.5 Bq kg−1 with a mean value 487.6 Bq kg−1 at 0–10 cm depth. For 10–20 cm depth interval, the 226Ra activity ranges from below detectable to 1823.6 Bq kg−1 with a mean value 296.0 Bq kg−1. Similarly the activity varies from below detectable to 1826.6 Bq kg−1 with a mean value of 211.0 Bq kg−1 for a depth interval of 20–30 cm. The activity of 40K at different depth is also discussed. Statistical analysis of radioactivity was also carried out. The results of these investigations are presented in this paper.  相似文献   

13.
The paper presents systematic studies on the vertical profiles of 210Po, an important decay product of 238U, in soils along coastal Kerala. Soil samples collected from different depth intervals 0–10, 10–20, 20–30 cm were analyzed for 210Po activity concentration by radiochemical methods. The activity 210Po in soil samples were counted using a ZnS(Ag) alpha scintillation counting system. The mean values of activity concentrations of 210Po in soil of various depths were found to be 8.66, 5.63 and 4.95 Bq kg−1 for depth intervals of 0–10, 10–20 and 20–30 cm, respectively. The overall activity concentration of 210Po in soil was found to vary from 2.26 ± 0.19 to 14.02 ± 0.12 Bq kg−1 with a mean value of 6.43 Bq kg−1. Maximum activity concentration was found in soil samples of Kollam region with the mean value of 10.08 ± 0.92 Bq kg−1. The activity of 210Po was found to be comparatively high in surface soil. The variation of 210Po activity concentration with organic matter contents was studied. 210Polonium activity concentration was found to increase with increasing organic matter content.  相似文献   

14.

Radioactivity measurements were performed, at the east (Georgia) and west (Romania) part of the Black Sea, for natural radionuclides and 137Cs in collected water and sediment samples using lab-based and in situ gamma-ray spectrometry. The activity concentrations of 137Cs at Georgian area in the sediment and seawater ranged between 20 to 50 Bq kg−1 and 8 to 25 Bq m−3, respectively while at the Romanian area the activity concentration ranged from 10 to 30 Bq kg−1 and 3 to 15 Bq m−3, respectively. The activity concentration values of 7Be at the Georgian area reached values up to (30 ± 4) Bq kg−1. The induced dose rates to marine organisms in both areas estimated by the ERICA assessment tool were much lower than the screening value of 10 μGy h−1.

  相似文献   

15.
The activity of 137Cs was determined in soils, mosses, lichens and other vegetation along the Caruay River and near the town of Kavanayen. The range of values for the soils was from <1.2 Bq·kg−1 of 137Cs (our detection limit) to 14.1 Bq·kg−1. The range of 137Cs activities in the mosses ranged from 9.9 to 17.9 Bq·kg−1 with a mean value of 13.4±4 Bq·kg−1; all the moss samples were found along the river. While the 137Cs activities in the lichens ranged from 9.1 to 29.8 Bq·kg−1; the two values along the river were about three factors higher than the one near Kavanayen. It was concluded that the 137Cs activities in the soils, mosses and lichens are much higher along the river in respect to the nearby town of Kavanayen.  相似文献   

16.
This study presents the high purity germanium (HPGe) gamma spectrometric measurement of natural radioactivity mainly due to 226Ra, 232Th and 40K in soil samples collected in Ferozepur and Faridkot district of Punjab, India. 226Ra activity varied from 28.6 to 51.1 Bq kg−1 with the mean of 39.7 Bq kg−1. The range and mean activity of 232Th were 42.9–73.2 and 58.2 Bq kg−1, respectively. 40K activity was in the range of 470.9–754.9 Bq kg−1 with the mean of 595.2 Bq kg−1. The air kerma rate (AKR) at 1 m height from the ground was also measured using gamma survey meter in all the sampling locations, which was ranging from 92.1 to 122.8 nGy h−1 with the mean of 110.6 nGy h−1. The radiological parameters such as Raeq and activity index of the soil samples were also evaluated, which are the tools to assess the external radiation hazard due to building materials. The mean and range of the Raeq values were 168.7 and 132.9–210.4 Bq kg−1, respectively, whereas the activity index varied from 0.5 to 0.8 with the mean value of 0.62. These indices show that the indoor external dose due to natural radioactivity in the soil used for the construction will not exceed the dose criteria. The AKR was also evaluated from soil activity concentration and altitude correction of cosmic radiation contribution. The statistical tests such as Pearson correlation, spearman rank correlation, box and whisker plot, the Wilcoxon/Mann–Whitney test and chi-square test, were used to compare the measured AKR with evaluated AKR, which indicates good correlation.  相似文献   

17.
The238Pu,239,240Pu and137Cs concentrations in sediments and shore deposition samples of the Vltava river were determined.239,240Pu and137Cs concentrations in sediment samples (five locations) ranged from 19.6 to 124.8 mBq·kg−1 and from 1.8 to 28.2 Bq·kg−1, respectively. The238Pu,239,240Pu and137Cs concentrations in shore deposition samples (four locations) ranged from 2 to 16.8, from 26.8 to 477.2 mBq·kg−1, and from 1.6 to 86.3 Bq·kg−1, respectively. The superficial activity of studied radionuclides in shore deposition areas was determined and radionuclide origin at studied locations was discussed.  相似文献   

18.
The uptake of 238U and 232Th in different parts of some selected plants used in traditional treatment of hypertension and diabetes in south-eastern Morocco (Errachidia area) has been studied using two different types of solid state nuclear track detectors (SSNTDs) LR-115 type II and CR-39. Plant uptake of radionuclides is one of many vectors for introduction of contaminants into the human food chain. Thus, it is critical to understand soil–plant relationships that control nuclide bioavailability. Soil concentrations of uranium ranged from 6.10 to 11.62 ppm, with a mean of 7.90 ppm. Soil concentrations of thorium ranged from 2.70 to 4.80 ppm, with a mean of 3.41 ppm. Mean uranium specific activities were 8.38 Bq kg−1 in root tissue, 5 Bq kg−1 in stem tissue and 6.02 Bq kg−1 in leaf tissue. Mean thorium specific activities were 2.53 Bq kg−1 in root tissue, 1.64 Bq kg−1 in stem tissue and 1.96 Bq kg−1 in leaf tissue. The transfer factors of 238U and 232Th from soil to different parts (root, stem, leaf, seed and fruit) of studied plant samples have been investigated. The transfer factors obtained for root plants were markedly higher than those for leaf, stem, fruit and seed plants. Soil-to-plant transfer factor (TF) is one of the most important parameters to be used in transfer models for predicting the concentration of radionuclides in agricultural crops and for estimating dose impacts to man. This study of uranium and thorium uptake in plants used in traditional medicine is also significant as far as the health hazard effects of uranium and thorium in human being are concerned.  相似文献   

19.
As a result of routine soil sampling to determine the 137Cs background activities country-wide in Venezuela, it was decided to further investigate El Mirador (Lookout) area at the base of the Sierra de Lema mountain range. In April 2003 (A), soil samples were collected at eight sites on and around the edge of the diabase outcrop to confirm that this area had anomalously high 137Cs activities. In July 2003 (B), not only soil samples were collected again, but also black mat, palm tree leaves and trunks, fruit bushes leaves and its fruit and fern leaves. The 137Cs content was measured by high resolution gamma-ray spectroscopy by a comparative method with reference materials. The 137Cs activity values range from 16.3 to 30.8 Bq·kg-1 in the soil samples collected in July 2003, 20.7–32.1 Bq·kg−1 for the black mat, 26.3–38.4 Bq·kg−1 for the palm leaves, 16.8–31.2 Bq·kg−1 for the palm trunks and 17.6–27.3 Bq·kg−1 for the fruit bush leaves, while, the 137Cs activity values for the whole fruit were between 23.4 and 30.7 Bq·kg−1; but, the value of the 137Cs activity in the center of the fruit (the edible part) was 51.6 Bq·kg−1, and the value of the 137Cs activity for the fern leaves was 51.8 Bq·kg−1. Thus, most of the 137Cs activity values determined in the soil, black mat and vegetation samples from El Mirador (Lookout) were considered anomalously high with respect to those found near the equator and in other areas of Venezuela. Only the center of the fruit from the Clusia grandiflora bushes and the fern leaves had high activity ratios, about a factor of three and could be considered as biomonitors that concentrate and retain the 137Cs. Finally, these anomalously high 137Cs activities have been attributed not only to the rich organic soils, as sinks, but also due to the affect of the cloud forests.  相似文献   

20.
232Th activities in the South Adriatic Sea-water, surface sediment, mud with detritus, seagrass (Posidonia oceanica) samples, and the mullet (Mugilidae) species Mugil cephalus, as well as soil and sand from the Montenegrin Coast, were measured using the six-crystal spectrometer PRIPYAT-2M, which has relatively high detection efficiency and a good sensitivity, and allows a short acquisition time, and measuring samples of any shape, without preliminary preparation and calibration measurements for different sample geometries. An average 232Th activity concentration in surface soil layer is found to be 40.33 Bq kg−1, while in sand—4.7 Bq kg−1. The absorbed dose rate in air due to 232Th gamma radiation from surface soil layer ranged from 11.76 to 63.39 nGy h−1, with a mean of 24.06 nGy h−1. Corresponding average annual effective dose rate has been found to be 0.03 mSv y−1. The absorbed dose rates due to the thorium gamma radiation in air at 1 m above sand surface on the Montenegrin beaches have been found to be from 0.41 to 9.08 nGy h−1, while annual effective dose rates ranged from 0.0005 to 0.011 mSv y−1. 232Th activity concentration in seawater ranged from 0.06 to 0.22 Bq L−1, as in the mullet (Mugil cephalus) whole individuals from 0.63 to 1.67 Bq kg−1. Annual intake of 232Th by human consumers of this fish species has been estimated to provide an effective dose of about 0.003 mSv y−1.  相似文献   

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