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1.
J Environ Radioact ; 178-179: 411-418, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28689881

RESUMO

The National Health and Medical Research Council and Natural Resource Management Ministerial Council of Australia developed the current Australian Drinking Water Guidelines which recommend an annual radiation dose value of 1 mSv year-1. One of the potential major contributors to the radiation dose from drinking water is radium-228, a naturally occurring radionuclide arising from the thorium decay series. Various methods of analysing for radium-228 in water have been established and adapted by analytical radiochemistry laboratories. Seven laboratories in Australia participated in analysing radium-228 spiked water samples with activity concentrations ranging from 6 mBq L-1 to 20 Bq L-1. The aim of the exercise was to compare and evaluate radium-228 results reported by the participating laboratories, the methods used and the detection limits. This paper presents the outcome of the exercise.


Assuntos
Laboratórios/estatística & dados numéricos , Monitoramento de Radiação , Rádio (Elemento)/análise , Poluentes Radioativos da Água/análise , Austrália
2.
J Environ Radioact ; 178-179: 419-425, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28711160

RESUMO

A large stainless-steel collection tray (with a surface area of one square metre) was purpose built and mounted on the roof of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) building at Yallambie, Victoria, Australia. Using this system two years' worth of wet/dry deposition samples have been collected and analysed. Smaller portable units were also developed for deployment in an emergency and/or for environmental monitoring. The cosmogenic radionuclide 7Be and the naturally occurring terrestrial radionuclide 210Pb have been used to validate the systems. The data from the smaller units was successfully compared to the larger permanent collection unit for validation, thus finding the portable units fit for purpose. Monitoring of wet and dry fallout deposition is an important response to radiological emergencies. It can provide useful information in verifying predictive models of radionuclide atmospheric transport and dispersion, in addition to providing local deposition data.


Assuntos
Poluentes Radioativos do Ar/análise , Berílio/análise , Radioisótopos de Chumbo/análise , Monitoramento de Radiação/instrumentação , Austrália
3.
J Environ Radioact ; 178-179: 426-429, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28602172

RESUMO

Following on from the successful development and validation of a prototype automated unit for the extraction of radiocaesium from seawater, the unit was redesigned to be smaller, easier to transport and better suited for field work. An extension of the validation process was undertaken to include robustness testing. Robustness testing evaluates the behaviour of a procedure when deliberate small changes are made. This requires the identification and testing of experimental factors which could have an impact on the results. The Plackett-Burman approach was adopted to minimise the number of experiments needed for testing. The study showed that the analytical method was not sensitive to any of the factors tested, indicating that the method is robust.


Assuntos
Radioisótopos de Césio/análise , Monitoramento de Radiação/instrumentação , Água do Mar , Poluentes Químicos da Água
4.
J Environ Radioact ; 153: 214-221, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26803402

RESUMO

A rapid method has been developed for the direct determination of radiostrontium ((89)Sr and (90)Sr) released in seawater in the early phase of an accident. The method employs a fast and effective pre-concentration of radiostrontium by Sr-Ca co-precipitation followed by separation of radiostrontium using extraction chromatography technique. Radiostrontium is effectively separated in the presence of excessive dominant salts of seawater. Cerenkov and liquid scintillation assay (LSA) techniques are used to determine (89)Sr and (90)Sr. Sample preparation time is approximately 4 h for a set of 10 samples. The method was validated using spiked seawater samples at various activity ratios of (89)Sr:(90)Sr ranging from 1:10 to 9:1. The mean chemical recovery of Sr was 85 ± 3%. (90)Sr showed variable relative bias which enhanced with increasing ratio of (89)Sr:(90)Sr and was in the range ± 21%. The highest biases of (90)Sr determination were due to lower activity concentrations of (90)Sr and are regarded as acceptable in emergency situations with elevated levels of radiostrontium in the sample. The minimum detectable concentration (MDC) of (90)Sr and (89)Sr varied at different (89)Sr:(90)Sr ratios. For 0.1 L seawater and 15 min counting time on a low background Hidex liquid scintillation counter (LSC), the MDC of (90)Sr was in the range of 1.7-3.5 Bq L(-1) and MDC of (89)Sr was in the range 0.5-2.4 Bq L(-1).


Assuntos
Monitoramento de Radiação/métodos , Água do Mar/química , Radioisótopos de Estrôncio/análise , Poluentes Radioativos da Água/análise , Liberação Nociva de Radioativos , Contagem de Cintilação
5.
J Environ Radioact ; 151 Pt 3: 530-6, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26330020

RESUMO

An automated unit was developed for the in-situ extraction of radiocaesium ((137)Cs and (134)Cs) from large volumes of seawater to achieve very low detection limits. The unit was designed for monitoring of Australian ocean and coastal waters, including at ports visited by nuclear-powered warships. The unit is housed within a robust case, and is easily transported and operated. It contains four filter cartridges connected in series. The first two cartridges are used to remove any suspended material that may be present in the seawater, while the last two cartridges are coated with potassium copper hexacyanoferrate for caesium extraction. Once the extraction is completed the coated cartridges are ashed. The ash is transferred to a small petri dish for counting of (137)Cs and (134)Cs by high resolution gamma spectrometry for a minimum of 24 h. The extraction method was validated for the following criteria: selectivity, trueness, precision, linearity, limit of detection and traceability. The validation showed the unit to be fit for purpose with the method capable of achieving low detection limits required for environmental samples. The results for the environmental measurements in Australian seawater correlate well with those reported in the Worldwide Marine Radioactivity Study (WOMARS). The cost of preparation and running the system is low and waste generation is minimal.


Assuntos
Radioisótopos de Césio/análise , Monitoramento de Radiação/métodos , Água do Mar/análise , Poluentes Radioativos da Água/análise , Austrália , Monitoramento de Radiação/instrumentação
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