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1.
In preparation for verification of the Comprehensive Nuclear-Test-Ban-Treaty, automated radioxenon monitoring is performed in two distinctive environments: Ottawa and Tahiti. These sites are monitored with SPALAX (Systeme de Prelevement d'air Automatique en Ligne avec l'Analyse des radioXenons) technology, which automatically extracts radioxenon from the atmosphere and measures the activity concentrations of (131m,133m,133,135)Xe. The resulting isotopic concentrations can be useful to discern nuclear explosions from nuclear industry xenon emissions. Ambient radon background, which may adversely impact analyser sensitivity, is discussed. Upper concentration limits are reported for the apparently radioxenon free Tahiti environment. Ottawa has a complex radioxenon background due to proximity to nuclear reactors and medical isotope facilities. Meteorological models suggest that, depending on the wind direction, the radioxenon detected in Ottawa can be characteristic of the normal radioxenon background in the Eastern United States, Europe, and Japan or distinctive due to medical isotope production.  相似文献   

2.
An international conference on polonium (Po) and radioactive isotopes was held in Seville Spain, 26-28 October 2009 at the Centro Nacional de Aceleradores. It was attended by 138 participants from 38 different countries. The sessions covered all aspects on Po and lead (Pb) such as radiochemistry, terrestrial and marine radioecology, kinetics, sedimentation rates, atmospheric tracers, NORM industries and dose assessment  相似文献   

3.
The Royal Decree of 20th July has entrusted the Federal Agency for Nuclear Control (FANC) with the task of controlling the territorial radioactivity and the doses received by the population. Within this agenda, a monitoring programme has been developed over many years, in order to follow the main potential exposure pathways of the population. In practice, several potential vectors of contamination are controlled: air (and rain), surface water (including sediments and biota), soils around nuclear installations, food chain, drinking water etc. To carry out such work, the FANC has collaborated with public or private reputable organisations: The Centre of Nuclear Energy Studies of Mol, The National Institute of Radionuclides of Fleurus, and The Louis Pasteur Public Health Institute of Brussels. A synthesis of this monitoring programme will be presented and the most important deductions will be pointed out. For many years, the tendency has been for tighter control of artificial and natural radioactivity in the environment. This has been achieved by increasingly stringent regulations, regarding environmental monitoring efforts, from international organisations (EC, OSPAR, IAEA). In this context, the FANC in Belgium, is involved in a process that will lead to the adaptation of the Belgian monitoring programme. Different aspects of these adaptations and of their consequences will be presented for illustrative purposes.  相似文献   

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Environment, Development and Sustainability - The necessity of making smart devices, intelligent processing and informative communication has taken the Internet of things (IoT) to a new level....  相似文献   

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During the Fifth Framework Programme (FP5) of the European Commission--according to an institutional programme in support to the policy of the European Commission for the implementation of Art. 35 and 36 of the Euratom Treaty as well as in the framework of the OSPAR Convention for the protection of marine environment of the north-east Atlantic--at the Institute for Transuranium Elements (ITU--General Directorate Joint Research Centre--European Commission), a reference laboratory for the measurement of radioactivity in the environment (MaRE laboratory) has been set up. In this paper, the principles and philosophy in order to improve the quality and reliability of analytical data for the measurement and monitoring of radioactivity in the environment under a quality assurance (QA) programme are presented. Examples of how a QA programme at the MaRE laboratory is developed and applied are given. Internal and external quality control (QC) programmes are also discussed.  相似文献   

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Prawn aquaculture industry is one of the developing economic activities in the Philippines. Generally, a wide range of microalgae typically grow and proliferate in many aquaculture ponds. However, certain species of microalgae have the ability to form harmful algal blooms (HABs) which often bring damaging consequences to the aquaculture industry, food safety, and the environment. The study aims to identify and characterize the composition of microalgae (particularly Cyanophyta) that are capable of forming HABs in selected freshwater prawn culture ponds in Central Luzon, Philippines, using morphological, ultrastructural, and molecular characterizations. From water samples collected in ten selected ponds across Central Luzon (Bulacan, Nueva Ecija, Pampanga, Tarlac, and Zambales), potential HAB formers such as Oscillatoria agardhii, O. princeps, Microcystis aeruginosa, and M. wesenbergii were observed to have occurred mostly, while Anabaena circinalis was only observed in one site. Both morphological and ultrastructural methods brought upon some challenges and limitations while molecular methods using 16S rRNA gene and phylogenetic analysis which were optimized in this study offered better and more efficient ways of identification and were helpful in resolving genus-level and species-level relationships. The influence of physicochemical properties of pond water, especially nutrient levels (nitrate, nitrite, and orthophosphate) on the occurrence of these cyanobacteria was also analyzed. As a pioneering study on freshwater HABs in aquaculture ponds in the country, results of the study can provide information to improve the knowledge in bloom occurrence and prediction, and to develop freshwater HAB prevention and control methods.  相似文献   

10.
Transparency and reproducibility remain challenges for sustainability assessment, particularly in developing world contexts where formal scientific information is often limited. We posit that even in such contexts, sustainability assessment can be productive and informative if the underlying assumptions about sustainability are made transparent. Thus, the process of assessment can be as instructive as the results, if not more so. In this article, we describe and discuss how we combined multicriteria decision analysis and system analysis as a unified approach to sustainability assessment. This approach is transparent, practical, flexible, and reproducible; it also facilitates the development of recommendations for enhancing sustainability. We illustrate the approach with examples from a recent environmental sustainability assessment of irrigated commercial maize production in Sinaloa, Mexico.  相似文献   

11.
Geostatistics is a field of statistics which development to solve estimation problems in the mining industry. Geostatistical techniques, however, can also be useful in the environmental sciences. For example, one geostatistical technique, called kriging, can be used to obtain unbiased, minimum variance estimates of the spatial distribution of a pollutant. In this discussion, an introduction to kriging is presented. In addition, a brief review of some of the applications of kriging in the fields of hydrology and geohydrology, soil science, agronomy, and contaminant monitoring is presented.  相似文献   

12.
The aim of this work was to determine the concentration of 234U and 238U and calculate the values of the 234U/238U activity ratio in waters and sediments from the various regions of the southern Baltic Sea: Gdańsk Deep, S?upsk Narrow and Bornholm Deep. The concentration of uranium in analysed sediments from southern Baltic increase with core depth to what probably is connected with diffusion from sediments to water through interstitial water, where uranium concentration is much higher than in bottom water. The highest concentrations of uranium were observed in sediments of S?upsk Narrow (0.66-7.11 mg kg(-1) d.w.) and S?upsk Bank (0.61-6.93 mg kg(-1) d.w.), the lowest in sediments from Bornholm Deep (0.54-3.77 mg kg(-1) d.w.). The 234U/238U activity ratio results indicated that the sedimentation of terrigenic material and Vistula River transport are the general sources of uranium in the southern Baltic sediments. The value of 234U/238U activity ratio in sediments from reduction areas from southern Baltic (Gdańsk Deep and Bornholm Deep) indicated that reduction process of U(VI) to U(IV) and removing of anthropogenic uranium from seawater to sediments constitutes a small part only in Gdańsk Deep.  相似文献   

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In post-closure radiological safety assessments of repositories for solid radioactive wastes, transfers of radionuclides to animal products are typically characterised using Transfer Factors (TFs), defined as the ratio of the concentration of the radionuclide in the animal product of interest to the rate of intake in diet. Such transfer factors can be measured directly in experimental studies, but they can also be estimated by use of biokinetic models for uptake and retention of radionuclides in animals. Based on a review of the literature, biokinetic models have been developed for the uptake and retention of iodine, technetium, selenium and uranium. These biokinetic models allow TF values to be estimated for different types of animals and for different animal lifetimes.For each radionuclide considered, reference values and ranges of TF values are estimated. These are summarised in Table 1.  相似文献   

15.
The concentrations and activity ratios of thorium isotopes in maritime airborne particles, collected over the western North Pacific along 137° E during cruises in January 1982 and 1983 and in March 1983, are reported here. The 232Th concentration in air is high at mid-latitude, near the Japanese islands and decreases southwards further from land. The 232Th concentration ranges from 0·036 to 0·22 μBq m−3. The 230Th/232Th activity ratio in the maritime air is almost unity, reflecting the U/Th activity ratio coupled with the crustal abundance. The 228Th/232Th activity ratio ranges from 3 to 69·5 and is, in general, higher than that in air over land. The results indicate the importance of the aeolian flux of the thorium isotopes, especially for 232Th and 228Th, in the geochemical cycle of thorium in the marine environment.  相似文献   

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Following the recognition of their usefulness by the authorities and the scientific community, automatic water monitoring networks were developed again to be able to measure seawater. For that purpose, they had to be fully autonomous, with low power consumption (solar panel power supply), wireless communicating (satellite, GSM, radio) and very sensitive (a few Bq/m3).  相似文献   

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A comprehensive analysis of samples from a frozen peat deposit in the upper reaches of the Khadytayakha River by palynological, carpological, entomological, and radiocarbon methods has been performed to reconstruct changes in the regional and local vegetation and climatic conditions during the Holocene. The results show that this peat deposit was formed from 8000 to 5000 years BP. During that period, the climate in the southern Yamal Peninsula was considerably warmer, and the present-day subarctic shrub tundra zone was occupied by plant communities of spruce, birch, and larch forests.  相似文献   

19.
Groundwater samples obtained from the Okchun Belt in Korea were separated into particulate and filtered fraction using a 0.45 microm membrane filter and concentrations and activity ratios of uranium isotopes in the fractions were determined by chemical separation and alpha-spectrometric measurements. Most of the uranium isotopes in the groundwater were found in the filtered water. Only less than 1% of the total uranium was detected in the particulate fraction. The concentrations and activity ratios of uranium isotopes in the groundwater measured in this study were variable, depending upon sampling site. Owing to a rapid material exchange between the subterranean hot waters and the rock strata, the concentrations of 238U in the groundwater in the hot spring area were found to be about four times higher than those elsewhere. Because of the alpha-particle recoil effect, the activity ratios of 234U/238U in the groundwater taken at "cold" spring sites were variable within the range 1.20 to 3.58, depending on the residence time of the groundwater. In the hot spring area, the activity ratios of 234U/238U were close to the equilibrium value (1.10 +/- 0.07) due to rapid erosion of the rock strata by the hot spring water.  相似文献   

20.
A variety of methods have been proposed, developed, and evaluated for detecting viruses, especially human enteric viruses, in water, wastewater, and other environmental samples, and continued developments and improvements have led to simpler and more reliable methodology. However, the use of currently available methods is still limited primarily to special circumstances, such as investigation of waterborne disease outbreaks, research studies on virus reductions by water and wastewater treatment processes and systems, especially reuse systems, and research monitoring and surveying of natural and treated waters. Widespread and routine virus monitoring is still not possible due to technical limitations and deficiencies of present detection methods and their relatively high cost. Although continued development of new methods and further improvement of existing methods is desirable, it is perhaps more important that current methods be systematically evaluated in carefully designed collaborative (round-robin) studies and quality assurance tests. Until virus detection methods are further improved and systematically evaluated, the establishment of virus standards for such materials as water and edible shellfish requiring routine monitoring appears to be unjustified.  相似文献   

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