Authors:Sultan Şahin, Fatih Külahcı, and Mahmut Doğru
In this study, 90Sr (540 keVβ −), 129I (150 keVβ −) and the gross beta radioactivity concentrations were determined for the samples of tea as the most leading consumed hot
drink in the markets (processed and packaged for sale) in our country. Furthermore, the obtained data were statistically analyzed.
For determination of 129I (150 keVβ−), 90Sr (540 keVβ−) and gross radioactivity concentrations in tea samples, a sensor system consisting of scintillation detector with BP4 probe
sensitive to beta radiation and a radiation meter (ST7) configurable for windows at desired power was used.
Authors:J. Dávila Rangel, H. López del Río, B. Rodríguez, and B. Solache-Ríos
The conditions to measure the gross alpha and gross beta radioactivity in water samples from Zacatecas and Guadalupe cities in the State of Zacatecas, Mexico were established. The gross alpha and beta radioactivity of water samples were measured using a liquid scintillation detector. The results show that the gross beta radioactivity in all cases is lower than the maximum contaminant level and the gross alpha radioactivity is higher in the samples collected from Guadalupe City and in the samples collected from the Southwest of Zacatecas City.
Authors:D. Rao, V. Sudheendran, A. Baburajan, S. Chandramouli, A. Hegde, and U. Mishra
The Environmental Survey Laboratory is responsible for the monitoring of radioactivity due to natural and artificially produced radionuclides in a variety of samples available around the nuclear facilities at Tarapur. Standard methods of radiochemical separation and counting are followed to determine -emitters in various matrices. To make the measurement simple and detect lower levels of contamination in some of the matrices, a method was developed to measure the high energy gross -activity primarily due to 90Y in borehole water and urine samples of occupational workers by Cerenkov counting in a liquid scintillation analyser. Cerenkov counting results of borehole samples were compared with the total gross -activity measured by a low background beta-counter. The combined measurements were used to evaluate 90Sr and 137Cs levels without chemical separation or gamma-spectrometry. Cerenkov counting technique was also utilised to evaluate 40K in drinking water and intercomparison water samples. The paper presents the methodology and results of a few measurements using the technique.
Authors:H. López-González, E. Quintero-Ponce, and L. Cervantes-Naranjo
The conditions to measure the gross alpha and gross beta radioactivity in water samples from the surrounding of the Nuclear
Center (Instituto Nacional Investigaciones Nucleares, (ININ), and Collection, Treatment and Storage Center for Low Level Radioactive
Waste (Maquixco) in the State of Mexico were established. The samples were collected from 1987 to 1996. The gross alpha and
gross beta radioactivity in the samples were determined by a gas-flow proportional counter. The results indicated that the
gross alpha and gross beta radioactive contamination in water samples were below the maximum contaminant level (MCL).
Gross beta (GB) activities were determined weekly for 13 years from filtered atmospheric aerosols, at 10 locations throughout New York State. Concentrations varied similarly among the sites and ranged from 0.03 to 1.5 mBq/m3. A comparison of variations with time and location were evaluated with respect to meteorological factors. Cosmogenic beryllium (7Be) concentrations were determined on 3-month composites of air filters and weekly in fallout at one site. The air filters nearly always contained observable activity (mean of 2.9 mBq/m3), while fallout activities were generally below the analytical detection limits. The seasonal variation of 7Be concentration in the atmosphere was similar at all locations and correlated with meteorological parameters. Concentrations of radioiodine (131I) were determined weekly on charcoal canisters at four sites. Only one site showed observable 131I activity (mean of 1.2 mBq/m3), due to the nearby incineration of dried municipal sludge. The source of the observed 131I was likely waste from hospital treatments.
Authors:S. Bhade, P. Reddy, A. Narayanan, K. Narayan, D. Babu, and D. Sharma
Simultaneous measurement of gross alpha and gross beta activities by liquid scintillation counting technique using LKB Wallac
Quantulus 1220 liquid scintillation counter (LSC) equipped with Pulse Shape Analyzer (PSA) is described. Three sets of pure
alpha and pure beta standards simulating the activity concentration values of real samples in terms of α/β activity ratios
were used to calibrate the LSC. Calibration methodology for the Quantulus 1220 with respect to the above measurements using
241Am and 90Sr/90Y standards of respective activity concentrations of ~25 dpm and ~104 dpm is described in detail. Also highlighted the need to calibrate the LSC using another set of 241Am and 90Sr/90Y standards of low and high activity concentrations respectively. The practicability and working performance of these calibration
plots was checked by the validation trials with test samples spiked with 241Am and 90Sr/90Y covering range of α/β activity ratios from 1:1 to 1:50.
A monitoring of radioactivity content was performed in drinking waters collected in Kahramanmaras. Gross alpha and gross beta
activities concentration were measured. The values of measured gross alpha and gross beta are compared with recommended WHO
(World Health Organisation) and ITS (Institution of Turkish Standards) guideline activity concentration. Obtained results
are in good agreement with the values recommended by WHO and ITS guideline activity concentrations for drinking water (except
for two values).
A chemical procedure for transferring deposited solid matter from a cellulose filter into the liquid scintillation cocktail has been described. The influence of chemical and color quenching on alpha and beta detection efficiency, as well as on misclassification of beta and alpha pulses was corrected by an external standard method. Under the chosen pulse shape discrimination level (PSD), the alpha and beta detection efficiencies were above 85% and spillovers of alpha and beta pulses were below 10% and 2% respectively. Determination limits for samples containing up to 200 mg of mineral matter were 0.015 mBq m–3 for alpha, 0.055 mBq.m–3 for210Pb and 0.055 mBq.m–3 for beta activity (counting time 12000 s and volume of filtered air 1000 m3). The method has been applied for routine monitoring of210Pb as well as for gross alpha and beta activities of longer-living radionuclides (T1/2.>11 hrs) in suspended air matter.
Gross-alpha and gross-beta activities of fourteen taps and wells, four lakes and three drinking water supplies in Elazi (Turkey) were determined. The results obtained indicate that although the natural radioactivity of six tap, two drinking, four lake and three well water samples does not exceed the requirements of the World Health Organisation (WHO) guidelines, however, most of them do exceed those of the Institution of Turkish Standards (ITS). Concentrations ranging from 0.02 to 0.17 Bq.l-1 and from 0.01 to 0.29 Bq.l-1 for gross-alpha and gross-beta radioactivity, respectively, were observed in all samples. For most of the samples, there were no regular correspondence between gross-alpha and gross-beta activity concentrations.
To examine inshore radioactive contamination caused by nuclear power plants, both gross -radioactivity and -spectrometry was measured. The measurements were taken with the sea mussels, Mytilus coruscus and Mytilus edulis, which had been collected from the four different sites of nuclear power plants (Kori, Ulchin, Wolsong, and Younggwang), and Cheju-do as a control site. As a result, the gross -radioactivity observed was similar to that in nature. Among radionuclides, only137Cs,20K,7Be and60Co were detected in a very small amount, and each was also close to the natural levels.