Search Results
Abstract
All commercially available mineral waters of Austrian origin were investigated with regard to the natural radionuclides 228Ra, 226Ra, 210Pb, 210Po, 238U and 234U. From 1 to 1.5 L of sample the nuclides were extracted and measured sequentially: the radium isotopes as well as 210Pb were measured by liquid scintillation counting after separation on a membrane loaded with element-selective particles (Empore Radium Disks), 210Po was determined by α-particle spectroscopy after spontaneous deposition onto a copper planchette and uranium was determined also by α-particle spectroscopy after anion separation and microprecipitation with NdF3. The calculated committed effective doses for adults, teens and babies were compared to the total indicative dose of 0.1 mSv/year given in the EC Drinking Water Directive. The dominant portion of the committed effective dose was due to 228Ra. Highly mineralised waters showed also higher 226Ra and 228Ra levels.
Abstract
During the International Scientific Cruise to Adriatic and Ionian Seas organised by the International Atomic Energy Agency, sediment and rock samples were collected. Sediments were sampled with grab corer at six locations in the Southeast Adriatic Sea. Rocks were collected on three islets in the Adriatic Sea. In the samples, natural radionuclides 238U, 234U, 232Th, 230Th, 226Ra and 210Pb were determined. After sampling and sample preparation, radiochemical separation procedures were applied. Then the samples were measured by alpha spectrometry system equipped with passivated implanted planar silicon detectors or by low background gas-flow proportional counter. Activity concentrations of natural radionuclides in samples were from 6.2 to 27.0 Bq/kg for 238U, from 7.9 to 28.1 Bq/kg for 234U, from 1.6 to 31.9 Bq/kg for 232Th, from 9.7 to 42.0 Bq/kg for 230Th, from 8.3 to 45.7 Bq/kg for 226Ra and from 3.0 to 113.4 for 210Pb. The obtained values are discussed in detail and compared with results of similar investigations carried out elsewhere.
Abstract
The present work investigated the activity concentrations of natural radionuclides 226Ra, 232Th and 40K in beach sand samples along coastal Kerala including high background radiation area. The activity of 232Th ranges from below detectable level to 23029.9 Bq kg−1 with a mean value of 2660.2 Bq kg−1 for 0–10 cm depth interval. For 10–20 cm depth, the 232Th activity ranged from below detectable to 4452.2 Bq kg−1 with a mean value of 815.5 Bq kg−1. The variation of 226Ra activity with depth is parallel with the 232Th activity distribution in beach sand. Its activity varied from below detectable to 5169.5 Bq kg−1 with a mean value 487.6 Bq kg−1 at 0–10 cm depth. For 10–20 cm depth interval, the 226Ra activity ranges from below detectable to 1823.6 Bq kg−1 with a mean value 296.0 Bq kg−1. Similarly the activity varies from below detectable to 1826.6 Bq kg−1 with a mean value of 211.0 Bq kg−1 for a depth interval of 20–30 cm. The activity of 40K at different depth is also discussed. Statistical analysis of radioactivity was also carried out. The results of these investigations are presented in this paper.
Abstract
High-uranium phosphate rock from Itataia, Brazil, was milled for wet-process phosphoric acid production using the dihydrate method. Uranium contained in the phosphoric acid was recovered by solvent extraction. The distribution of long-lived natural radionuclides of the 238U and 232Th decay series involved in these operations was evaluated. 226Ra, 228Ra and 210Pb were found to predominate in the phosphogypsum, while 228Th, 230Th and 232Th in the uranium-free phosphoric acid. Thorium is removed from the phosphoric acid by solvent extraction to produce a NORM-free phosphoric acid.
Abstract
In this study the concentration of natural radionuclides has been investigated in soil and water of Karun river by using a high resolution (HPGe detector, n-type) γ-spectrometry. The concentrations range in water sample was 47.6 ± 5.6–130.8 ± 6.3, 0.0–23.4 ± 0.5 and 0–6.4 ± 2.0 Bq L−1 for 40K, 232Th and 226Ra respectively. For soil samples the concentration range of 275.7 ± 8.6–458.6 ± 6.8, 19.2 ± 5.35–41.1 ± 3.95 and 29.9 ± 1.53–50 ± 1.54 Bq kg−1 was obtained respectively for 40K, 232Th and 238U. 137Cs was also detected in some part of the region in soil samples. The mean concentration of 137Cs was 5.5 ± 0.6 Bq kg−1. The origin of this activity is unknown. The average absorbed dose rate in outdoor air at a height of 1 m above the ground was found to be 54.3 ± 3.7 nGy h−1. The results of this study indicate that the area has standard background radiation level.
Abstract
The distribution of natural radionuclides,40K,226Ra, and232Th, in freshwater sediments and in coal-fired power-plant ash repositories has been tested for lognormality. Thereafter, lognormality for natural radionuclide concentration frequency distribution was accepted with a high probability. The lognormal natural radionuclide distribution in sediments and coal-ash indicated single population groups. The anthropogenic modifications of the natural radionuclide concentrations in the environment are indicated. The adsorbed dose rates, in mGy y–1, in air from gamma field of the natural radionuclides were calculated.
Abstract
The building materials and products whose content of natural radionuclides are contributors to the radiation exposure of the population. In this study several types of building materials used for construction of living buildings in Slovakia were examined. The concentrations of natural radionuclides (226Ra,232Th and40K) were determined by 
-ray spectrometry with an HPGe detector. In the second part of the work, sixty samples of building products (panel), used for dwelling construction in several towns in Slovakia, were analysed. The concentration of natural radionuclides and the radium equivalent activity content in the inner-and outerside of the wall were estimated. The results were used for the calculation of the annual mean effective photon dose rates, by the model and calculation procedure of KRISIUK and KARPOV.
Abstract
A method for the absolute calibrations of 
-rays spectrometers for voluminous samples using natural radionuclides is suggested. The method is based on relative calibration with a solution of 232Th salts and absolute calibration with K2CO3 or KCl.
Abstract
Sediments collected from tidal saltmarsh areas in South Australia have been analysed for natural radionuclides from the uranium and thorium decay series. The concentrations observed indicate a significant enhancement of some nuclides in comparison to inland soils, consistent with the recent incorporation of uranium, thorium and actinium into the sediments. The probable source of the nuclides is sea-water. It has been experimentally established that the organic residues from the decay of vegetable matter play a major role in this process.
Abstract
A highly salt tolerant shrub, samphire (Halosarcia halocnemoides), found growing in the soild alkaline residues in an evaporation pond at a former uranium and monoazite treatment plant, has been analysed for natural radionuclides and rate earths. The data obtained have been copared with that for plants from the local natural environment. Vegetation-to-soil concentration ratios have been determined. The radionuclide concentration ratios for samples from the contaminated site are similar to those from the natural environment. Significant differences have been noted in the case of the rare earth elements with an apparent preferential incorporation of the light rare earth elements into the plant growing in the chemical residues.
