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EN
Anthropogenic activities, such as high-altitude flights and living in buildings, have enhanced the public exposure to natural radiation. In particular, 40K and radionuclides belonging to 232Th and 238U decay chains are present even in building materials, and they may be considered as partially responsible for the effective dose coming from natural radioactivity. Scientists and governments have devoted great attention to the evaluation of the effects produced on the public by naturally occurring radionuclides. In this context, to evaluate the building materials acceptability, accurate and reliable methods for the measurement of the specific activity of natural radioactive isotopes in building materials have been developed. This paper aims to provide a clear and exhaustive review on natural radionuclide measurement procedures. Several standard national normatives (Dutch NEN 5697, Italian UNI 10797, Polish ITB 455), based on gamma spectrometry, have been considered and some critical issues were identified regarding the preparation and the radiometric measuring of the samples. Therefore, the direct measurement of 238U and 232Th by ICP-MS spectrometry as well as the extrapolation of the specific activities without waiting for secular equilibrium have been considered as two promising alternative approaches.
EN
Naturally occurring radioactive material (NORM) still remains a problem in oil and gas exploration. Radioactive wastes from oil and gas drilling take the form of produced water, drilling mud, sludge, slimes, or evaporation ponds and pits. In many parts of the USA the soil contains radioactivity that is then concentrated in mineral scales on the pipes, storage tanks and other extraction equipment. The radionuclides 226Ra and its one of daughter products 210Pb and 228Ra from 232Th are the primary radionuclides of concern in the waste. We have investigated the concentrations of heavy metals in NORM using neutron activation analysis (NAA) as well as using passive radioactivity counting using Compton suppressed gamma-ray spectrometry. With a low-energy germanium counter and the Compton suppression system low detection limits were achieved to measure 226Ra, 228Ra and 210Pb. Results have shown very elevated amounts for these radionuclides as well as the heavy metals of barium and strontium.
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