primarily on the geological and geographical conditions, and appear at different levels in the soil of each region in the world . Cosmogenic radionuclides are produced by the interaction of cosmic- rays with atomic nuclei in the atmosphere, w primordial ones (terrestrial background radiation) were formed by the process of nucleo-synthesis . The great interest expressed worldwide for the study of naturally occurring radiation and environmental radio activity has led to interest in extensive surveys in many countries. Natural sources still contribute almost 80% of the collective radiation exposure of the world’s population. There are many sources of radiation and radioactivity in the environment. Gamma radiation emitted from naturally occurring radionuclides, also called terrestrial background radiation, represent the main external source of irradiation of the human body [3,4]. Significant amount of man-made radionuclides 137 Cs and 90 Sr may be also present in the soil and plant as a result of testing of nuclear weapons in the atmosphere, accidents, such as Chernobyl accident, and the routine discharge of radionuclides from nuclear installations. The contribution of other nuclides to the total activity is negligible . Once present in the environment, these radionuclides, whether natural or artificial,
Abstract: The aim of the present study was to investigate the activity concentrations of natural radionuclides in different seasonal fruits of Bangladesh. In total 20 samples of 16 different kinds of fruits were collected from the local markets of Bangladesh. The radioactivity of these samples was measured by using Gamma Spectrometry System. The radioactivity of natural radionuclides in the studied seasonal fruit samples were found to be ranged from BDL to 31.13±10.63 Bqkg -1 with an average 10.95 Bqkg -1 due to 238 U, from 1.55±0.73 to 34.59±7.43 Bqkg -1 with an average 6.68 Bqkg -1 due to 232 Th and from BDL to 733.25±61.17 Bqkg -1 with an average 308 Bqkg -1 due to 40 K. Artificial radionuclide was not found in the studied fruit samples. The maximum activities of 238 U, 232 Th and 40 K were observed, respectively in coconut, jujube and papaya. However, the average concentrations of all radionuclides mentioned above in the studied samples were found to be less than the world average. The total annual internal effective dose from the consumption of radioactive fruits was found to be 8.39 µSv/y. The value the annual effective dose in all samples in this study was lower than ICRP 72; therefore, the values natural radioactivity and annual effective dose in the seasonal fruits are found to be safe and no health-hazards are createdfor the population of Bangladesh.
The concentrations of natural radionuclides, radium-226, radium-228, and potassium-40, and the artificial ra- dionuclide caesium-137, in river bottom sediments and suspended matter were monitored in the Czech Republic by the Czech Hydrometeorological Institute during the period 2000-2010 and 2001-2010 respectively. The data were used to evaluate the natural background levels of these radionuclides and the impact of human activities on the water environment. For potassium-40 in sediments, the natural background level was estimated to be 570 Bq/kg. To evaluate the background level for radium-226, the river sites affected by human activities (mining and processing uranium ore, coal) were eliminated from the assessment. The average natural background values were 47.8 Bq/kg for radium-226 and 47.2 Bq/kg for radium-228 in sediments and 86.5 Bq/kg for radium-226 and 87.9 Bq/kg for radium-228 in suspended matter. The river sediments were identified as good indicators of ra- dioactive contamination, especially radium-226, which recorded historic contamination due to former uranium mining and milling. The radium-226 contamination rate was assessed using the ratio of radium-226 to radi- um-228. This ratio was used to classify sediment according to the relative contamination from the uranium in- dustry. The residual contamination of caesium-137 due to the Chernobyl accident in 1986 was also assessed. Av- erage values of caesium-137 were 14.0 Bq/kg in sediments and 25.0 Bq/kg in suspended matter.
This paper deals with 2D distribution of 238 U, 226 Ra, 232 Th, 40 K and 137 Cs in soils located between two sources of pyrogenic carbon - coal extraction in “Maritza-iztok” mine and electricity production in “Maritza-iztok 2” Thermal Power Plant in order to trace a possible increase of radiation background and dose load of population. Smolnitsa (Pellic Vertisol) located outside industrial complexes is a control soil. Specific mass activity of natural radionuclides varied within the typical range for Bulgarian soils (Bq.kg -1 ): 238 U 27-100; 226 Ra 27-73; 232 Th 29-60; and 40 K 400-700. Activity of 137 Cs also falls in the normal range after Chernobyl accident. Soils vulnerable to pyrogenic carbon inputs show higher activity of radiocaesium (18.7 Bq.kg -1 ) compare to control soil (3.8 Bq.kg-1). Activity of 40 K is also higher (12.5-43.0%) and also safe from radioecological point of view.
The average absorbed dose rate in Lake Bosomtwe was found to be 15.452.00 nGy/h and 10.444.10 nGy/h for Bui Dam, both being lower than the acceptable international value of 59.00 nGy/h in sediments (UNSCEAR, 2000). The absorbed dose rate and annual effective dose, calculated, were also lower than those reported earlier for Lake Bosomtwe in Ghana (Darko et al., 2011) and the one reported in Egypt (Fahmi et al., 2010). The percentage contribution of the radionuclides to the absorbed dose rate were 46%, 30%, and 24% for 40 K, 232 Th and 238 U, respectively. In Bui Dam, however, 232 Th was the highest contributor (47%) followed by 238 U (33%) and 40 K (20%). The differences between the 2 reservoirs may be due to the different mineralogical and geochemical compositions of the soils and rocks that outcrop in both study areas.
17 Read more
in plants used for medicinal purpose since plants are the primary pathway of natural radionuclides entering into the human body through the food chain. Radionuclides and their decay products from 238 U and 232 Th series to- gether with 40 K are terrestrial primordial radionuclides, which originated from the earth’s crust and are the sources of natural radioactivity in the environment .
6. Muhammad, Musa Auwal; Idris, Isa Funtua; Simon, Peter Malam and Arabi, Suleiman Abdullahi, “Distribution of Gamma-Emitting Radionuclides in Soils around the Centre for Energy Research and Training (CERT) Ahmadu Bello University, Zaria, Zaria-Nigeria.” Journal of American Science, 6(12) (2010).
The artificial machines with natural intelligence of the future will be, pre- sumably, much more powerful and capable of much more complex thoughts than the ones a human mind could have. Consequently, a second of thinking of one of these machines would probably contain more information than an entire encyclopedia. Their senses would have a greater detail of resolution and as a consequence a wider bandwidth and since thoughts are built based on the senses they are constructed upon, their thoughts would be much more complex and capable of a wider bandwidth than a human being could have.
In order to assess any radiological hazard, the exposure to radiation arising from radionuclides present in soil and effluents was determined in terms of many parameters. Different known radiation health hazard indices analysis is being used in radiation studies to arrive at a reliable conclusion on the health status of an irradiated person and environment in recent studies (Diab et al.2008; Agbalagba and Onoja, 2011). To assess the radiation hazards associated with the collected soil and effluents samples, eight quantities have been defined (Zarie and Al Mugren, 2010).
The Radioactivity is a spontaneous emission of particles or electromagnetic radiation, or both from an unstable nucleus. There are three kinds of radiation which is alpha particle, beta particle and gamma rays with consisting of high energy of photon energy. The natural radioactivity element is commonly can be found in the nature such as air, soil and water. Their characteristic is typically long lived, with half-lives often on the order of hundreds of millions of years.
(J. eﬀusus, C. palustris, M. arundinacea) from the contaminated site. But this does not represent any risk to the environment due to low activity con- centration of the measured radionuclides in the plants. The obtained results show the highest values of for 226 Ra and the lowest ones for 230 Th in all three plant species. The activity concentration was diﬀerent for each plant species. An inﬂuence of the calcium content on the radium activity concen- tration in plants was only observed in Caltha palustris. Further investigation is required to clarify this phenomenon.
14 Read more
Previous attempts to control cellular behavior were mainly based on genetic engineering. While useful, such an approach suffers from several complications. Living cells grow and evolve which could lead to modifications of the engineered circuits, causing not only the loss of their functions but also an altering of the environment. However, other methods are possible. All living cells can naturally sense and respond to their environment and to each other. Thus, artificial, non- living cells can be engineered to activate already existing natural cellular pathways. In this way, the genetic engineering component moves from the natural to completely artificial, laboratory-made cells. Moreover, synthetic systems operating in living organisms also depend on elements with unknown function, leaving many gaps in the understanding of how living cells work. Building life- like systems with non-living components could help reveal unrecognized but necessary cellular mechanisms. However, the design of functional, genetically encoded cell-free systems is difficult, because biological parts have been evolved to function optimally inside of living cells. In vitro conditions are different.
186 Read more
be attributed to the nature of the phosphate rock, the depth of sampling  and differences in the industrial process applied to obtain phosphoric acid. Natural ra- dioactivity in the different phases of the production system has recently been analysed by Bolivar et al.  showing that Pb, Ra and to a certain extent Th isotopes are exclusively supplied by the phosphate rock and remain associated to the PG particles, while uranium decreases according to the number of washings of the PG.
The feature of living organisms to collect quantitative information on the physico-chemical characteristics of the biosphere makes them a good indicator of changes in the ecological status of certain site or area. Basic characteristics of such organisms, bioindicators, are the ability to accumulate several or selected elements with low sensitivity, wide distribution and presence in large amounts in various environments, no seasonal differences in availability and applicability, and the existence of correlation between accumulation and input to the ecosystem (1-3). The most common representatives of bioindicators are mosses. Mosses adopt nutrients from the atmosphere by dry and moist desorption through weakly or no developed cuticles, which makes them good bioindicators of environmental pollution with heavy metals, pesticides, and radionuclides (4-7). Having no real roots, leaves, and stem with large surface area in relation to their weight, mosses grow slowly with minimal morphological changes during the lifespan. They are widespread, long-lived, and easy accessible, which makes them suitable for applications as pollution indicators (8-12).
Soil-plant-man is recognized as a major pathway for the transfer of radionuclides to human beings [(Safety Series, No. 57 (IAEA 1982)]. The radioactivity of environmental samples from sites and products suspected of contamination must be investigated before free access to them is given to the public (Owono 2010). Radionuclides in soils are frequently transferred to different plant tissues by direct transfer via the root system, or by fallout of radionuclides and resuspension of contaminated soil followed by deposition on plant leaves (Noordijk et al. 1992). The uptake of radionuclides from soil to plant is characterized by the transfer
14 Read more
Plume rise is calculated by using the momentum plume model since ash emission velocity at the chimney exit is known. An average lid for the assessment area is provided as part of the input data. The agricultural data like beef cattle density, milk cattle density and land frac- tion cultivated for vegetable crop and others for the re- gion are inputted to the code in order to estimate of emitted radionuclides into the food chain.
The presence of natural radionuclides as 238U- and 232Th series and 40K “in water causes health hazards owing to the human internal exposure from the absorbed into the body through ingestion. Thus, measurement of natural radioactivity in drinking water is necessary for public health studies, which allows the evaluation of population exposure to radiation by the consumption of water” (Fatima et al., 2007). “The radioactivity in drinking water may be man-made, resulting from waste discharges and atomic bomb fallout, or produced naturally by the dissolution of gasses and rock minerals”(Todorović et al., 2012). Also, Heavy metals such as Cd, Cu, Mn, Ni, Pb and Zn are essential at very low level of intake and are potentially harmful to live organisms at some level of exposure and absorption (Kalay and CANLI 2000). The daily consumption of water is indubitable and cannot be deferred by humans. As a consequence, monitoring the quality of drinking water is essential to secure the public health. Natural radionuclides and heavy elements in drinking water have been widely studied to estimate the safety of drinking water on its radionuclide and metal’s content. "e.g., (Davutluoglu et al. 2011; Almayahi, Tajuddin, and Jaafar 2012; Abdul et al. 2012; El-Gamal et al. 2013; Aytas et al.
Investigations were conducted to determine the radionuclide concentration levels in the major rivers in Pahang state, Malaysia. Since the rivers are the main sources for water supply in the state, it is important to measure natural radionuclide concentrations in the rivers. Seventeen water samples were collected from major rivers in Pahang state. The concentration of uranium, thorium and potassium were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The samples were found to contain permissible levels of radionuclides with a mean activity concentrations of uranium, thorium and potassium found to be 8.49 ± 0.34 mBq L -1 , 1.74 ± 0.27 mBq L -1 and 77.85 ± 0.96 mBq L -1 respectively. The ratio between thorium and uranium concentration is found to be 3:4 due to the higher solubility of uranium than thorium in water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured around the area. A good relation was observed between uranium and thorium concentrations with gamma dose rate obtained around the area while no relation was found between the potassium concentrations with gamma dose rate. Significance of the results obtained is discussed.
11 Read more
According to the results of table (4), the average concentration of uranium for sedimentary rocks is high in content and low in content of thorium and percentage potassium comparable with U. All of these rocks are classified to middle –member of Um Bogma Formation as pervious illustrated. Th/U (ppm) ratio indicates depletion or enrichment of radioisotopes, which it ranges from 0.01 to 0.21 except one sample (H-8) is 0.0027. These results are very low from natural value which indicates relative U enrichment as U was migrated from its source and
The study of the activity ratios between radionuclides belonging to the uranium series provides information about the relative mobility of these ra- dionuclides. In this sense we observed the greatest mobility to correspond to the uranium isotopes, with the thorium isotope being the least mobile. At the point most inﬂuenced by the installation, there was a high activity con- centration of 230 Th in the surface layer. This activity concentration rapidly fell oﬀ to the values of uninﬂuenced points, indicating the low mobility in depth of this radionuclide. In contrast, at this same point the uranium iso- topes reached a depth of at least 40 cm. In general, the natural radionuclides presented little migration in depth, with the maximum depth achieved be- ing by uranium isotopes, such as was seen in the case of 238 U at 40 cm at the point most inﬂuenced by the installation, which had a greater activity concentration than the same depth for soils not inﬂuenced by the mine.