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1.
Radiological hazards of coal and ash samples collected from Xi’an coal-fired power plants of China 总被引:1,自引:0,他引:1
Xinwei Lu Loretta Y. Li Fengling Wang Lijun Wang Xu Zhang 《Environmental Earth Sciences》2012,66(7):1925-1932
The natural radiological characteristics and their respective annual effective dose (AED) rates, produced by 226Ra, 232Th and 40K in coal, fly ash and bottom ash from two large coal-fired power plants (CFPPs) of Xi’an were determined by means of γ-ray
spectrometry. The average activity concentrations of 226Ra, 232Th and 40K in all ash samples (fly ash and bottom ash samples) from the two CFPPs were 67.6, 74.3 and 225.3 Bq kg−1, respectively. The results are compared with data from other locations. To evaluate the radiological hazards of the natural
radioactivity, the radium equivalent activity (Raeq), air absorbed dose rate (D), AED and external hazard index (H
ex) are compared with internationally accepted values. Raeq and H
ex of all samples except three fly ash samples were less than the limits of 370 Bq kg−1 and unity, respectively. The average D and AED for ash samples were 86.8 nGy h−1 and 0.11 mSv y−1, respectively, which exceed the world average and Xi’an average values. 相似文献
2.
S. A. War P. Nongkynrih D. T. Khathing P. S. Iongwai L. M. Dkhar 《Environmental Earth Sciences》2012,65(6):1695-1703
Primordial radionuclides in sand sediments that are often used as constructing materials are one of the sources of radiation
hazard in dwellings. Activity concentrations of the primordial radionuclides of 40K, 226Ra and 232Th have been measured in sand sediments collected from streams and streamlets lying within and around the uranium mineralization
deposit blocks of Kylleng-Pyndensohiong, Mawthabah Areas of West Khasi Hills District, Meghalaya, India. The technique of
gamma-ray spectroscopy using a NaI(Tl) detector with a PC-based multi channel analyser was applied for determination of the
activity concentrations. The activity of the sand sediments obtained in this study ranges from 95.3 to 1,088.8 Bq kg−1 for 40K; 38.3 to 784.1 Bq kg−1 for 226Ra and 78.0 to 316.1 Bq kg−1 for 232Th. Sand sediments from two sampling locations lying within the mineralization zone show highest concentrations of these radionuclides.
The radiological hazards of the sand sediments were calculated using various models given in the literature. The radium equivalent
activity was found to be higher than the accepted standard criterion value of 370 Bq kg−1 and the values of external and internal hazard indices were also found to be higher than unity in these two sampling locations.
Besides these two sampling locations, a sampling location lying at a nearby distance from the mineralization zone also exhibits
hazard indices values greater than unity. 相似文献
3.
Measurement of natural radioactivity in sand samples collected from the Baoji Weihe Sands Park, China 总被引:1,自引:0,他引:1
The activity concentrations and the gamma-absorbed dose rates of the primordial naturally occurring radionuclides 226Ra, 232Th and 40K were determined for sand samples collected from the Baoji Weihe Sands Park, China, using γ-ray spectrometry. The natural radioactivity concentration of sand ranges from 10.2 to 38.3 Bq kg−1 for 226Ra, 27.0 to 48.8 Bq kg−1 for 232Th and 635.8 to 1,126.7 Bq kg−1 for 40K with mean values of 22.1, 39.0 and 859.1 Bq kg−1, respectively. The concentrations of these radionuclides are compared with the typical world values and the average activity of Chinese soil. The measured activity concentration of 226Ra and 232Th in sand is lower than the world average while that of 40K is higher. . To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate, and the effective dose rate have been calculated and compared with internationally approved values. The radium equivalent activity values of all sand samples are lower than the limit of 370 Bq kg−1. The values of the external hazard index are less than unity. The mean outdoor air absorbed dose rate is 69.6 nGy h−1 and the corresponding outdoor effective dose rate is 0.085 mSv y−1. 相似文献
4.
Gamma activity from the naturally occurring radionuclides namely, 226Ra, 232Th, the primordial radionuclide 40K was measured in the soil of Cuihua Mountain National Geological Park, China using γ-ray spectrometry technique. The mean
activity of 226Ra, 232Th and 40K were found to be 27.2 ± 6.5, 43.9 ± 6.2 and 653.1 ± 127.6 Bq kg−1, respectively. The concentrations of these radionuclides were compared with the typical world values and the average activities
of Chinese soil. The radium equivalent activity, the air absorbed dose rate, the annual effective dose rate, and the external
hazard index were evaluated and compared with the internationally approved values. All the soil samples have Raeq lower than the limit of 370 Bq kg−1 and H
ex less than unity. The overall mean outdoor terrestrial gamma dose rate is 66.3 nGy h−1 and the corresponding outdoor annual effective dose is 0.081 mSv. 相似文献
5.
Radioactivity in sediments and gross alpha–beta activities in surface water of Fırtına River, Turkey
B. Kücükömeroglu A. Kurnaz R. Keser F. Korkmaz N. T. Okumusoglu G. Karahan C. Sen U. Cevik 《Environmental Geology》2008,55(7):1483-1491
The concentrations and distribution of natural and artificial radionuclides in sediment and water samples collected from Fırtına
River in the Eastern Black Sea region of Turkey were investigated with an aim of evaluating the environmental radioactivity
and radiation hazard. Natural gross α and gross β activities were determined for 21 different water samples, and the activity
concentrations were obtained for 226Ra, 214Pb, 214Bi, 228Ac, 208Tl, 40K and 137Cs in 20 different sediment samples. The obtained results showed that natural gross α and gross β activity concentrations
in water samples range from 12.4 ± 3.4 to 66.2 ± 9.2 mBq l−1 and from 27.9 ± 3.3 to 133.3 ± 4.1 mBq l−1, respectively. The mean activity concentrations were 32.6 ± 3.8 mBq l−1 for gross α and 69.9 ± 4.4 mBq l−1 for gross β. Generally, the gross β activities were higher than the corresponding gross α activities. The average concentrations
of 238U and 232Th daughter products vary from 11 to 167 Bq kg−1 and from 16 to 107 Bq kg−1, respectively. The concentrations of 40K and 137Cs vary from 51 to 1,605 Bq kg−1 and from 0.8 to 42 Bq kg−1, respectively. Sediment characterization was also investigated using grain size, thin section and XRD analysis. 相似文献
6.
I. Yigitoglu E. Eser B. Cetin S. Kilicaslan F. Oner I. Akkurt G. Gursoy S. Yamcicier H. Koç 《Arabian Journal of Geosciences》2018,11(6):128
In this study, the environmental radioactivity measurements for Tokat and Sivas provinces in the northeast of Turkey were performed. Using gamma ray spectrometry, the activity concentrations of natural radionuclides in soil and travertine samples (232Th, 226Ra, and 40K) were determined. The annual effective dose equivalent, the absorbed doses rate in air, the radium equivalent, and the external hazard index were obtained from these activities. The activity concentrations vary from 9.09 to 17.04 Bq kg?1 for 232Th, from 36.53 to 76.95 Bq kg?1 for 226Ra, and from 216.56 to 576.59 Bq kg?1 for 40K in soil samples. The activity concentrations in travertines vary from 15.99 to 21.01 Bq kg?1 for 232Th, from 19.89 to 67.71 Bq kg?1 for 226Ra, and from 179.89 to 314.43 Bq kg?1 for 40K. The average dose rate in air for soil and travertine samples was 43.41 and 41.05 nGy h?1 respectively. The obtained results are presented and compared with other studies, and the results of this study are lower than the international recommended value (55 nGy h?1) given by UNSCEAR ( 2000). The results show that the region has a background radiation level within the natural limits. 相似文献
7.
Natural radioactivity in sediment of Wei River,China 总被引:1,自引:0,他引:1
The concentrations of natural radionuclides in sediment of Wei River of China were measured using γ-ray spectrometry with
the aim of estimating the radiation hazard as establishing a database for radioactivity levels of river sediment of China.
The activity concentrations of 226Ra, 232Th and 40K in sediment samples ranged from 10.4 to 39.9 Bq kg−1, 15.3 to 54.8 Bq kg−1 and 514.8 to 1,175.5 Bq kg−1, respectively. The concentrations of these radionuclides were compared with the typical world values and the average activities
of Chinese soil and Shaanxi soil. Radium equivalent activity (Raeq), external hazard index (H
ex) and representative level index (I
γr) were calculated for the samples to assess the radiation hazards arising due to the use of these sediment samples in the
construction of dwellings. All the sediment samples have Raeq lower than the limit of 370 Bq kg−1, H
ex less than unity and I
γr close to 1 Bq kg−1. The overall mean outdoor terrestrial gamma dose rate is 64.8 nGy h−1 and the corresponding outdoor annual effective dose is 0.079 mSv. None of the studied location is considered a radiological
risk and sediment can be safely used in construction. 相似文献
8.
Terra rossa and eutric cambisol soils were surveyed in Slovenia. At both sites, 6–13 boreholes were drilled in a regular 24 m × 24 m
square grid. Soil samples from various depths were taken for gamma spectrometric analysis, and radon in soil gas was measured
at a depth of 80 cm using an AlphaGuard instrument. The following ranges of activity concentration (Bq kg−1) were obtained for 238U, 226Ra, 228Ra, 40K and 137Cs: in terra rossa, 64–74, 70–84, 45–49, 293–345, 20–30 and, in eutric cambisol, 55–80, 132–147, 50–57, 473–529, 106–272.
Radon activity concentrations in both soils ranged from about 100 kBq m−3 to 370 kBq m−3. 相似文献
9.
Oil mineral leases (30, 58 and 61) in Delta and River States are the major oil blocks in the oil and gas rich Niger Delta region of Nigeria that is characterized by environmental degradation from oil and gas activities. This research work presents an analytical approach on natural radioactivity assessment in soil and sediment in 15 oil fields of these OMLs. Concentrations of natural radionuclides (226Ra, 232Th and 40K) were determined using gamma spectroscopy. The mean activity concentration of 226Ra, 232Th and 40K for OML30 is 40.2 ± 5.1, 29.9 ± 4.2 and 361.5 ± 20.0 Bq kg?1, respectively; the corresponding values obtained for OML58 is 20.9 ± 2.8, 19.4 ± 2.5 and 260.0 ± 14.1 Bq kg?1, respectively. While the mean activity concentration of 226Ra, 232Th and 40K for OML61 is 29.3 ± 3.5, 21.6 ± 2.6 and 262.1 ± 14.6 Bq kg?1, respectively. These values obtained show enhanced NORMs, but are well within the world range and values reported in some regions and countries of the world, and are slightly above control values, values obtained in Southwestern region of Nigeria and some countries reported average values. The study also examined some radiation hazard indices, the mean values obtained are 86.6 ± 9.3 Bq kg?1, 0.6 Bq kg?1, 40.8 ηGy h?1, 0.05 μSv y?1, 0.2 and 0.3 for radium equivalent activity (Raeq), representative level index (Iγ), absorbed dose rates (D), annual effective dose rates (E ff dose), external hazard index (H ex) and internal hazard index (H in), respectively. These calculated hazard indices to estimate the potential radiological health risk in soil and sediment are well below their permissible limits. The soil and sediments from the study area provide no excessive exposures for the inhabitants and can be used as construction materials without posing any radiological threat or harm to the public users. However, oil-field workers and host community residents are cautioned against excess exposure to avoid future accumulative dose of these radiations from sludge and sediment of this area. 相似文献
10.
An initial on-going survey of the activity concentrations of 226Ra, 232Th and 40K for sand samples collected within the coastal strip of 290 Ramsar site evaluated the external hazard index, the outdoor annual effective dose equivalent and the radium equivalent activity, to elucidate potential risks for the resident inhabitants. The range of mean activity concentrations in the whole area for 226Ra, 232Th and 40K were between 4.12?±?0.26 and 48.3?±?1.4, 5.47?±?0.55 and 194?±?13, 77.7?±?4.2 and 445?±?18 Bq kg?1, respectively. The Barra de Valizas–Aguas Dulces region had the highest activity concentrations of 226Ra and 232Th. The annual effective dose equivalent for this region was higher than the mean worldwide value, whereas it is lower than the recommended values for public exposure. 相似文献
11.
E. B. Faweya M. J. Ayeni G. O. Olowomofe H. T. Akande 《International Journal of Environmental Science and Technology》2018,15(9):1967-1982
In this study, activity concentrations of 40K, 226Ra and 232Th in fertilized soil samples and different organic and inorganic fertilizers used in agricultural soil were analysed using gamma-ray spectrometry NaI (Tl) detector in order to access the implications of extended use of fertilizers in 2–3 years. The concentrations of radionuclides in some granular fertilizer brands were discovered to be higher for 40K, 226Ra and 232Th than those obtained in leafy fertilizer, animal fertilizer and fertilized soil samples. From the results, the highest overall mean concentrations of the specific activities of 40K, 226Ra and 232Th were 2301.8 (granular fertilizer), 42.5 (leafy fertilizer) and 327.1 (animal fertilizer) in Bq kg?1, while the lowest values observed in the specific activities of the same radionuclides were 357.7 (leafy fertilizer), 28.1 (animal fertilizer) and 36.5 (animal fertilizer). The radiological hazards of the radium equivalent (Raeq), normative value (NRN), outdoor radium equivalent (Raeq-out), external hazard index (H ext), internal hazard index (H in), dose rate, annual effective dose rate, activity utilization index and concentration accumulation index (CAI) and RaFZ due to the presence of these radionuclides in the investigated samples were calculated. Nevertheless, some of the fertilizer brands have higher concentration values than the recommended limit, and the values of hazard indices of fertilizer brands used in the selected teaching and research farms were within acceptable limit. Therefore, the fertilized soil samples in the studied farms are safe. 相似文献
12.
Sermin Çam Kaynar Muslim Murat Saç F. Serap Ereeş 《Environmental Earth Sciences》2014,71(4):1581-1592
In this study, radioactivity measurements in the environment of Akhisar, Gölmarmara, Gördes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of 40K, 238U and 232Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of 40K, 238U and 232Th in soils ranged 2.80–2,347.77, 9.90–256.19 and 9.66–106.53 Bq kg?1, respectively. The activity of 226Ra in the water samples ranged from 0.03 Bq L?1 (0.89pCi/L) to 0.80 Bq L?1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h?1), annual effective dose rate (mSv year?1) and radium equivalent activity (Bq kg?1) were calculated and compared with international standard values. 相似文献
13.
Osman Günay 《Arabian Journal of Geosciences》2018,11(24):782
The activity concentrations of 226Ra, 232Th, and 40K are measured in soil samples from various locations in the Kadikoy and Uskudar district of Istanbul (Turkey). The 226Ra activity concentrations range from 19.97 Bqkg?1 to 50.80 Bqkg?1 and average 226Ra concentration value 31.40 Bqkg?1 was calculated. The 232Th activity concentrations range from 21.38 Bqkg?1 to 52.61 Bqkg?1 and average 232Th concentration value 34.44 Bqkg?1 was calculated. The 40K activity concentrations range from 464.06 Bqkg?1 to 711.27 Bqkg?1 and average 40K concentration value 619.59 Bqkg?1 was calculated. In addition, radium equivalent (Raeq), absorbed gamma dose rate (D), annual effective dose equivalent, (AEDE), excess lifetime cancer risk (ELCR) were calculated in this study. All of the calculations have been compared with both national and international standards and similar studies. As a result of this comparison, levels of natural radioactivity and radiological effects were slightly higher than the World average and Turkey. 相似文献
14.
K. M. Yeager P. H. Santschi K. J. Schindler M. J. Andres E. A. Weaver 《Estuaries and Coasts》2006,29(3):443-454
Determining sources of sediment to coastal systems is an important and complex problem that figures prominently in a myriad
of geological, geomorphological, geochemical, and biological processes. Lithogenic (226Ra,228Ra,228Th,230Th,232Th) and fallout (137Cs,210Pb) isotopes were employed in conjunction with sedimentological methods to determine rates of sedimentation in the Nueces
Delta and Nueces-Corpus Christi Estuary and to assess the relative importance of marine versus terrestrial sediment sources
to the estuary. Similarity of lithogenic isotope ratios in surface sediments throughout the system precluded a numeric approach
to discerning the importance of each of the two large scale sediment sources (terrestrial and marine). A stepwise, graphical
examination of discrete lithogenic isotope activity concentrations shows more promise. Terrestrial, marine, and bay sediment
means for226Ra versus232Th,226Ra versus230Th, and228Ra versus232Th show that terrestrial and marine sediment sources have different signatures, despite having similar grain size distributions
(sands), and that sediment deposited in Nueces and Corpus Christi Bays are indistinguishable from the terrestrial component.
Supporting evidence is provided by thorium isotopes,230Th versus232Th,228Th versus232Th, and228Th versus230Th. Nueces Delta sedimentation (0.09–0.53 g cm−2 yr−1) shows a subtle gradient, with rates generally lower in the west and progressively higher moving east, likely reflecting
contrasts in land use and topography. Nueces Bay cores differ from those in Corpus Christi Bay in that sands comprise a larger
percentage of their composition, and they are mixed over greater depth, most likely due to geographic and physiographic effects.
Sediment accumulation rates consistently decrease over the first 20 km from the Nueces River and become constant after that,
implying that the river is the most significant source of sediment to the estuary. The interpretation of sediment supply to
this estuary as dominated by terrestrial inputs is based on three complimentary sets of data: sediment grain size distributions,
discrete lithogenic isotope data (Ra versus Th and Th versus Th), and sediment accumulation rates for both Nueces and Corpus
Christi Bays. 相似文献
15.
N. Krishnamoorthy S. Mullainathan R. Mehra Marcos A. E. Chaparro Mauro A. E. Chaparro 《Environmental Earth Sciences》2014,71(8):3593-3604
The natural radioactivity levels and magnetic measurements in sediment samples of Bharathapuzha river for the first time have been determined. Bottom sediments from 33 locations were collected to determine 226Ra, 232Th and 40K using a HPGe detector based on the high-resolution gamma spectrometry system, and magnetic susceptibility by using Bartington MS2 magnetic susceptibility meter. The calculated activity concentrations of 226Ra, 232Th and 40K have been found to vary from 21.21 to 66.03 Bq kg?1, 33.49 to 93.10 Bq kg?1 and 232.25 to 899.66 Bq kg?1, respectively. The results have been compared with worldwide recommended values and also with radioactivity measurements in river sediments of India and other parts of the world. The air-absorbed dose rate, indoor and outdoor annual effective dose rates and radium equivalent activity are calculated with an aim to access the radiation hazards arising due to the use of these materials in the construction of buildings and their mean values obtained are 74.83 nGy h?1, 367.08 μSv y?1, 91.77 μSv y?1 and 157.09 Bq kg?1, respectively. The mass-specific magnetic susceptibility values ranged widely from 35.4 to 2,160.5 × 10?8 m3 kg?1 and compared with other rivers in South India. Multivariate statistical analyses were performed to describe the magnetic and radioactivity relevance of the different groups of samples. The data obtained in the present study may be useful for radiological and magnetic mapping of the study area in the future. 相似文献
16.
R. E. Masto L. C. Ram P. R. Shandilya S. Sinha J. George V. A. Selvi 《Environmental Earth Sciences》2011,64(4):1107-1115
Coal handling, crushing, washing, and other processes of coal beneficiation liberate coal particulate matter, which would
ultimately contaminate the nearby soils. In this study, an attempt was made to determine the status of soil bio-indicators
in the surroundings of a coal beneficiation plant, (in relation to a control site). The coal beneficiation plant is located
at Sudamudih, and the control site is 5 km away from the contaminated site, which is located in the colony of Central Institute
of Mining and Fuel Research Institute, Digwadih, Dhanbad. In order to estimate the impact of coal deposition on soil biochemical
characteristics and to identify the most sensitive indicator, soil samples were taken from the contaminated and the control
sites, and analyzed for soil organic carbon (SOC), soil N, soil basal respiration (BSR), substrate-induced respiration (SIR),
and soil enzymes like dehydrogenase (DHA), catalase (CAT), phenol oxidase (PHE), and peroxidase (PER). Coal deposition on
soils improved the SOC from 10.65 to 50.17 g kg−1, CAT from 418.1 to 804.11 μg H2O2 g−1 h−1, BSR from 8.5 to 36.15 mg CO2–C kg−1 day−1, and SIR from 24.3 to 117.14 mg CO2–C kg−1 day−1. Soils receiving coal particles exhibited significant decrease in DHA (36.6 to 4.22 μg TPF g−1 h−1), PHE (0.031 to 0.017 μM g−1 h−1), PER (0.153 to 0.006 μM g−1 h−1), and soil N (55.82 to 26.18 kg ha−1). Coal depositions significantly (P < 0.01) decreased the DHA to 8.8 times, PHE to 1.8 times, and PER to 25.5 times, but increased the SOC to 4.71 times, CAT
to 1.9 times, SIR to 4.82 times, and BSR to 4.22 times. Based on principal component analysis and sensitivity test, soil peroxidase
(an enzyme that plays a vital role in the degradation of the aromatic organic compounds) is found to be the most important
indicator that could be considered as biomarkers for coal-contaminated soils. 相似文献
17.
Sophie Rihs Damien Lemarchand Marie-Claire Pierret François Chabaux 《Geochimica et cosmochimica acta》2011,75(23):7707-7724
The recent chemical dynamics of a podzolic forest soil section (from the Strengbach watershed, France) was investigated using U- and Th-series nuclides. Analyses of (238U), (230Th), (226Ra), (232Th), (228Ra) and (228Th) activities in the soil particles, the seepage waters, and the mature leaves of the beech trees growing on this soil were performed by TIMS or gamma spectrometry. The simultaneous analysis of the different soil (sl) compartments allows to demonstrate that a preferential Th leaching over Ra must be assumed to explain the (226Ra/230Th), (228Ra/232Th) and (228Th/228Ra) disequilibria recorded in the soil particles. The overall Ra- and Th- transfer schemes are entirely consistent with the prevailing acido-complexolysis weathering mechanism in podzols. Using a continuous open-system leaching model, the (226Ra/230Th) and (228Ra/232Th) disequilibria measured in the different soil layers enable dating of the contemporary processes occurring in this soil. In this way, we have determined that a preferential Th-leaching from the shallow Ah horizon, due to a strong complexation with organic colloids, began fairly recently (18 years ago at most). The continual increase in pH recorded in precipitations over the last 20 years is assumed to be the cause of this enhanced organic complexation. A lower soil horizon (50-60 cm) is also affected by preferential Th leaching, though lasting over several centuries at least, with a much smaller leaching rate. The migration of Th isotopes through this soil section might hence be used as a tracer for the organic colloids migration and the induced radioactive disequilibria demonstrate to be useful for assessing the colloidal migration kinetics in a forested soil.Ra and Th isotopic ratios also appear to be valuable tracers of some mineral-water-plant interactions occurring in soil. The (228Ra/226Ra) ratio enables discrimination of the Ra flux originating from leaf degradation from that originating from mineral weathering in shallow −10 cm seepage soil waters. It appears that, at least in some cases, the Ra-isotopic ratio measured in forest-soil seepage waters may not be representative of the Ra-isotopic ratio released from mineral weathering, indicating that the different origins of the dissolved 226Ra and 228Ra must be taken into account. 相似文献
18.
Celalettin Simsek 《Environmental Geology》2008,55(8):1637-1646
Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene
aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated
with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity
levels of 226Ra, 232Th and 40K were compared with world averages. The average activity levels of 226 Ra, 232Th and 40K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13
and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have
high 226Ra and 40K levels according to world average level. As these sediments are used as construction materials and in agricultural activities
within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium
equivalent activity (Raeq) and radiation hazard index (Iyr). All the samples have Raeq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and Iyr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important
contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as
agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep
groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high 226Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi
uranium site and the environment. 相似文献
19.
Jelena Petrović Milan Đorđević Ranko Dragović Boško Gajić Snežana Dragović 《Environmental Earth Sciences》2018,77(7):290
The main focus of this study was to assess radiation exposure to human and non-human biota due to natural radionuclides in soil of the Serbian capital. For the first time, ERICA tool was employed for calculation of gamma dose rates to non-human biota in this area. In analyzed soils, the mean values of 226Ra, 232Th and 40K specific activities were found to be 35, 43 and 490 Bq kg?1, respectively. The distribution of analyzed natural radionuclides in soils was discussed in respect to its statistically significant correlations with sand, silt, clay, carbonates, cation exchange capacity and pH value. The annual outdoor effective dose rates to the population varied from 48 to 98 μSv, and the total dose rates to terrestrial biota, calculated by ERICA tool, varied from 9.84?×?10?2 μGy h?1 (for tree) to 5.54?×?10+0 μGy h?1 (for lichen and bryophytes). The results obtained could serve as a baseline data for the assessment of possible anthropogenic enhancement of the total dose rate to human and non-human biota of the study area. 相似文献
20.
Kanchan Wakadikar Avik Sil Niranjan Kolekar Shalini Tandon Rakesh Kumar 《Environmental Earth Sciences》2011,64(1):25-28
Drilling fluids are used for drilling natural gas, oil and water wells. These spill over into the surrounding soil at the
point of drilling, which may impair soil health. A laboratory investigation was carried out to determine the effect of non
aqueous drilling fluid (NADF) and synthetic base oil used with it on soil health as indicated by the dehydrogenase activity.
A non-sterile sandy loam soil was treated with different amounts of NADF and base oil at a rate of 800, 8,000 and 16,000 mg kg−1. Initially, reduction in dehydrogenase activity was observed, but it increased with the incubation time. On the 60th day
of incubation dehydrogenase activity in untreated control was 1.04 mg TPF g−1 h−1 whereas in the soil samples treated with NADF and the base oil (16,000 mg kg−1), the activity was 1.53 mg TPF h−1 and 1.90 mg TPF h−1, respectively, which was 72 and 82% more than in untreated control. Base oil-treated soil showed more dehydrogenase activity
than that observed with NADF. Both NADF and base oil stimulated the soil dehydrogenase activity. 相似文献