It has been analyzed in this article the radioactivity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and radiological hazard parameters in different types of cements commonly used in Poland and available on the Polish market. The radiological hazard parameters are, in particular, absorbed gamma dose rate, annual effective dose, radium equivalent activity, the external hazard index, and the gamma and alpha indices. The radionuclide activities of the most important radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K have been determined by gamma-ray spectrometry with the use of two kinds of spectrometers of different operational parameters. One performed also measurements on 30-day and 45-day aged samples as to verify if there is a statistically significant difference in radioactivity concentration for shorter and longer aging time. The radioactivity concentrations in the cement samples ranged from 21.7–75.7 Bq·kg⁻¹ for ²²⁶Ra, 12.3–47.3 Bq·kg⁻¹ for ²³²Th to 123–430 Bq·kg⁻¹ for ⁴⁰K. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Ra_eq = 127 Bq·kg⁻¹, mean absorbed gamma dose rate D = 115 nGy·h⁻¹, mean annual effective dose E = 570 µSv·y⁻¹, external hazard index H_ex = 0.32, internal hazard index H_in = 0.51, mean activity concentration index I_γ = 0.47 and mean alpha index I_α = 0.28. The results were compared with the reported data from other countries and the international standard values given by European Commission (EC) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR 2000). Finally, thorough statistical analysis has been performed.

The measurements of the specific activity of natural radioactive isotopes of radium (²²⁶Ra), thorium (²³²Th) and potassium (⁴⁰K) in chosen samples of imported (China, Finland, Spain, India, Sweden) and Polish (Izerski, Karkonosze, Siedlimowicki, Strzegomski, Strzelinski) granites were performed. The measurements were carried out with 2 × 2” NaI(Tl) scintillation detector. The measured specific activity on natural radioactive isotopes were within the following ranges: 5.8–312 [Bq kg⁻¹], 5.5–189 [Bq kg⁻¹] and 109–1590 [Bq kg⁻¹] for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. Obtained concentrations of radioactive isotopes allowed to perform the analysis of the exposure of the humans from the ionizing radiation emitted by the granites. The determination of the exposure consisted in the calculation of absorbed gamma dose rate (D) [nGy h⁻¹] for each sample, which fell in the range between 20 and 511 [nGy h⁻¹], annual effective dose rate (AED) [mSv year⁻¹] ranging between 0.10 and 2.50 [mSv year⁻¹], radium equivalent activity (Ra_eq) [Bq kg⁻¹] with values between 22 and 570 [Bq kg⁻¹], external and internal hazard indices (H_ex) and (H_in) falling in the ranges 0.06−1.53 and 0.08–2.41 respectively, as well as gamma (I_γ) and alpha (I_α), representative level indices with values 0.08–2.0 and 0.029–1.56, respectively. Moreover, obtained results were compared with the international standard values given by the European Commission (EC), the United Nations Scientific Committee on the Effects of Atomic Radiation given in UNSCEAR Reports, and the results of research from other laboratories.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informuj

In 1986, the Chernobyl disaster provoked the uncontrolled release of significant amounts of radioactive substances, which caused surface contamination in Poland through radioactive isotopes. The most affected areas are Opole Voivodeship and part of Lower Silesian Voivoideship. Unfavorable meteorological conditions consisting of strong winds blowing from Chernobyl and local heavy rains favored the spread of a radioactive cloud, its shifting towards Poland and the accumulation of artificial isotopes in the soils of those regions [1]. Samples of the soils surface layers (0 - 10 cm) collected in different regions of Lower Silesian Voivodeship during the period 1988 - 2014 were studied. Changes in concentrations over time were analyzed for the following natural and artificial radionuclides: cesium (¹³⁷Cs and ¹³⁴Cs), potassium (⁴⁰K), radium (²²⁶Ra) and actinium (²²⁸Ac). Since the disaster, the concentration of ¹³⁷Cs in the surface layer decreased continuously over time. The mean concentration of ¹³⁷Cs in the surface layer in Lower Silesian Voivodeship in 2014 was 1.46 kBq/m², higher than the mean concentration for the whole Poland at 1.33 kBq/m² [2]. Mean concentrations of other natural radionuclide such as ²²⁶Ra, ²²⁸Ac and ⁴⁰K in the soils of Lower Silesian Voivodeship were also found to be higher than for the whole Poland [2].