Determination of 226Ra in TENORM Sample Considering Radon Leakage Correction

Background: Phosphogypsum is material produced as a byproduct in fertilizer industry and is generally used for building materials. This material may contain enhanced radium-226 (226Ra) activity concentration compared to its natural concentration that may lead to indoor radon accumulation. Therefore, an accurate measurement method is proposed in this study to determine 226Ra activity concentration in phosphogypsum sample, considering the potential radon leakage from the sample container.Materials and Methods: The International Atomic Energy Agency (IAEA) phosphogypsum reference material was used as a sample in this study. High-purity germanium (HPGe) gamma spectrometry was used to measure the activity concentration of the 226Ra decay products, i.e., 214Bi and 214Pb. Marinelli beakers sealed with three different sealing methods were used as sample containers. Due to the potential leakage of radon from the Marinelli beaker (MB), correction to the activity concentration resulted in gamma spectrometry is needed. Therefore, the leaked fraction of radon escaped from the sample container was calculated and added to the gamma spectrometry measured values.Results and Discussion: Total activity concentration of 226Ra was determined by summing up the activity concentration from gamma spectrometry measurement and calculated concentration from radon leakage correction method. The results obtained from 214Bi peak were 723.4 ± 4.0 Bq· kg-1 in MB1 and 719.2 ± 3.5 Bq· kg-1 in MB2 that showed about 5% discrepancy compared to the certified activity. Besides, results obtained from 214Pb peak were 741.9 ± 3.6 Bq· kg-1 in MB1 and 740.1 ± 3.4 Bq· kg-1 in MB2 that showed about 2% difference compared to the certified activity measurement of 226Ra concentration activity.Conclusion: The results show that radon leakage correction was calculated with insignificant discrepancy to the certified values and provided improvement to the gamma spectrometry. Therefore, measuring 226Ra activity concentration in TENORM (technologically enhanced naturally occurring radioactive material) sample using radon leakage correction can be concluded as a convenient and accurate method that can be easily conducted with simple calculation.

Penilaian Dampak Bahaya Radiologis terhadap Radionuklida Natural di Pesisir Pulau Bengkalis

Latar belakang : Radionuklida natural ditemukan hampir di semua media lingkungan, dan di lingkungan laut terdeteksi cukup tinggi karena adanya proses erosi, pelapukan dan daur ulang mineralyang mengalami perpindahan melalui badan air. Radionuklida natural tersebutdapat berpindah ke berbagai media, termasuk ke manusia melalui rantai makanan.Penelitian ini dilakukan untuk memberikan informasi dasar mengenai tingkat radioaktivitas di lingkungan perairan laut di Pesisir Pulau Bengkalis dan melakukan penilaian dampak bahaya radiologis melalui aktivitas ekuivalen radium (Raeq) dan indeks bahaya eksternal (Hex)serta laju dosis eksternal dari radionuklida natural.Metode: Metode deskriptif digunakan dalam penelitian ini dan metode pengambilan sample sedimen menggunakan metode purposive sampling. Sampelsedimen dikumpulkan dari 6 titik pengambilan sampel di pesisir Pulau Bengkalis, menggunakan sediment grab. Sampel kemudian dikeringkan dan dihomogenkan kemudian ditimbang sebanyak 1 kg. Pengukuran aktivitas radionuklida dilakukan menggunakan spektrometri gama dengan waktu cacah selama 3 hari. Aktivitas 226Ra ditentukan berdasarkan emisi sinar gamma 214Pb dan 214Bi. Aktivtias 232Th ditentukan berdasarkan emisi 212Pb dan 228Ac dan 40K ditentukan dari emisi pada 1461,8 keV. Hasil analisis akan digunakan untuk menghitung dampak radiologis di lingkungan mengunakan ekuivalen aktivitas radium dan indeks bahaya eksternal.Hasil: Aktivitas rata-rata berturut turut 56,45 ; 31,34 ; 26,04 ; 33,19 ; 30,00 dan 185,49 Bq/kg untuk radio nuklida226Ra, 212Pb, 214Pb, 214Bi, 228Ac dan 40K. Aktivitas terukur mempunyai kisaran nilai yang berdekatan dengan pengukuran di beberapa negara.Penghitungan nilai aktivitas ekuivalen radium (Raeq) berkisar dari 82,61 - 138 Bq/kg dan tidak melebihi nilai yang ditetapkan oleh ICRP (1990) dan OECD (179) yaitu sebesar 370 Bq/kg. Nilai indeks bahaya eksternal (Hex) masih dibawah 1, dengan nilai rata rata sebesar 0,31, dan laju dosis dari radionuklida natural sebesar 37,175 nGy/h.Simpulan:Aktivitas radionuklida natural di pesisirPulauBengkalismempunyai kisaran nilai yang berdekatan dengan pengukuran di beberapa Negara. Nilai aktivitas ekuivalen radium (Raeq) Yang terukur tidak melebihi nilai yang ditetapkan oleh ICRP (1990) dan OECD (179). Nilai indeks bahaya eksternal (Hex) masih dibawah 1, dan laju dosis yang diserap lingkungan dari radionuklida natural masih dibawah nilai rata rata dunia. Dengan demikian, dapat disimpulkan bahwa parameter radiologis radionuklida natural dalam sedimen di pesisir Pulau Bengkalis berada dalam batas yang dapat diterima. AbstractTitle : --Background: Natural radionuclides are found in almost all environmental media, and in the marine compartment have been detected relative high due to the process of erosion, weathering and recycling of minerals that come trough the water bodies. Radionuclides can move to various media, including to the humans through the food chain. This research was conducted to provide baseline information about the activity of radioactivity in the marine environment of the Bengkalis Island Coast and conduct radiological hazard impact assessments through equivalent radium (Raeq) and external hazard index (Hex) and external dose rates of natural radionuclides.Method: Descriptive methods were used in this study and the sediment sampling method used a purposive sampling method. Sediment samples were collected from 6 sampling points on the coast of Bengkalis Island, using sediment grab. The samples were then dried, homogenized and weighed 1 kg. Measurement of radionuclide activity was carried out using gamma spectrometry with counting time for 3 days. The 226Ra activity is determined based on 214Pb and 214Bi gamma ray emissions. The 232Th activity was determined based on 212Pb and 228Ac and 40K emissions determined from emissions at 1461.8 keV. The results of the analysis will be used to calculate the radiological impact in the environment using equivalent radium activity and external hazard index.Results: The average activity are 56.45; 31.34; 26.04; 33.19; 30.00 and 185.49 Bq/kg for radionuclides 226Ra, 212Pb, 214Pb, 214Bi, 228Ac and 40K respectively. The value of this activity comparable withthe activities in several countries.The calculation of radium equivalent activity (Raeq) values ranges from 82.61 - 138 Bq / kg and does not exceed the value 370 Bq / kg by ICRP (1990) and OECD (179). The external hazard index value (Hex) is still below 1, with an average value of 0.31, and the dose rate of natural radionuclides is 37,175 nGy / h.Conclusion: Natural radionuclide activity on the coast of Bengkalis Island has a range of values adjacent to measurements in several countries. The measured value of radium (Raeq) activity does not exceed the value set by ICRP (1990) and OECD (179). The external hazard index value (Hex) is still below 1, and the absorbed dose rate of natural radionuclides is still below the world average value. Thus, it can be concluded that the radiological parameters of natural radionuclides in sediments on the coast of Bengkalis Island are within acceptable limits.

RANKING OF THE TERRITORY OF THE CITY OF MOSCOW FOR POTENTIAL RADON DANGER

Purpose. The identification and hygienic assessment of main sources of natural exposure of the population of the city of Moscow. Ranking areas of the territory of the city according to the potential radon hazard. The elaboration of criteria for the radon hazard of the territory. Material and Methods. There are provided data of the radiation control of the territory of the city (g-spectrometry, the determination of the activity of natural radioactive substances, including samples of the soil and in lithological layers, the density of radon flux (DRF) from the soil), surveys of residential and public buildings for different purposes according to the content of the equivalent equilibrium volumetric activity of radon (EEVAR). Results. There is presented the analysis of materials concerning the evaluation of results of radiation control (the of 226Ra activity in different types of soils, the levels of the DRF from the soil, the concentration of radon in newly constructed and operated buildings, various premises) in administrative districts of Moscow. There was executed the comparison of the spatial distribution of the fields of DRF and EEVAR values in basements and premises of buildings exceeding 200 Bq/m3. There was performed the analysis of criteria of radon-dangerous of areas. Conclusion. There were substantiated criteria and zones of the aggravated radon danger within the city according to following indices: 226Ra content in soils, DRF on soil surfaces, EEVAR in premises, annual dose of the radiation. Performed long-term studies allowed to rank the territory of Moscow into various zones of the radon danger and allocate most dangerous areas (South-Eastern Administrative District, South Administrative District, South-Western Administrative District). There was obtained a map of the interrelationship of the spatial distribution of anomalous DRFs from the soil surface and elevated EEVA values in premises. Ranging of areas for the radon danger permits to significantly optimize the system of radiation control and measures for radiation protection of the population.

MODELLING OF 226Ra ACTIVITY CONCENTRATIONS ALONG OGUN RIVER, SOUTH WESTERN NIGERIA

This work was aimed at generating a model using least square approximation technique to predict values of activity concentrations of 226Ra in any location along Ogun river in Nigeria using experimental data. Sediment samples were collected in thirty two locations along the river of about 400 km in length. NaI(Tl) gamma-ray spectrometer system was used to obtain activity concentrations of 226Ra.The aver-age value of activity concentration of 226Ra in the sediment samples from the upper region through the middle to the lower region of the river was found to be 12.65 ± 3.48 Bq/kg, having values ranging from 5.57 ± 2.36 Bq/kg (at Ekerin) to 20.40 ± 4.52 Bq/kg (at Sokori). From this work, it was observed that the generated model and experimental data could be used to predict values of activity concentrations of 226Ra in any location along the river once the latitude and longitude (position) are known. Statistical tests on the model also showed that there were no significant differences between the experimental and predicted data of 226Ra and that 98.70% of the experimental data were predicted by the model.

Distribution of natural radionuclides and radon concentration in the riverine environs of Cauvery, South India

Systematic studies were carried out to understand the distribution of natural radionuclides in sediments and radon in water in the riverine environs of Cauvery, one of the major rivers of South India. The activity of radionuclides in the sediment was measured by gamma ray spectrometry. The radon emanation from the sediment was measured by the sealed ‘can technique’ and the radon in the water was measured using the RAD-7 instrument. The mean values of 40 K, 226Ra, and 232Th in the sediment samples were found to be 297.3 ± 4.16 Bq kg−1, 75.1 ± 2.64 Bq kg−1, and 85.5 ± 2.62 Bq kg−1, respectively. The mean activity of radon, radon exhalation rate, and radium content were found to be 135.68 Bq m−3, 327.1 mBq m−1 h−1, and 133.03 mBq kg−1, respectively. The radon in the water ranged from 0.19 kBq m−3 to 1.40 kBq m−3. The hyper pure germanium gamma spectroscopy measured via 226Ra activity and the radon activity measured by the passive can technique showed good correlation. The mean value of radon in the water was within the internationally recommended level. The sediment was considered safe for the purpose of construction, except for some extreme values, and the water was deemed safe for drinking.

Pilot study of 222Rn and 226Ra activity concentrations in groundwaters of Roztocze region, Poland

Authors selected 5 intakes of groundwaters outflowing from carbonate rocks in Roztocze region in Poland and measured activity concentrations of 222Rn and 222Ra. The average values of 222Rn and 226Ra activity concentrations were: 5.3 (min. 2.0, max. 8.3 Bq/dm3) and 0.06 Bq/dm3 (from <0.06 to 0.07 Bq/dm3) respectively. To make a comparison authors made also investigations in groundwaters from other regions built of carbonate rocks in Poland (Sudetes, Kraków-Częstochowa Upland, Lublin Upland, Tatra Mountains). In groundwaters from these regions, 222Rn activity concentration was from 2.2 to 47.8 Bq/dm3, while mean value was 16.0 Bq/dm3. All of 226Ra activity concentration values measured in these regions were below LLD (< 0.05 Bq/dm3). Results from Roztocze and other regions are comparable. All of investigated waters according to new polish regulations about limits of 222Rn and 226Ra activity concentrations could be used as drinking waters (the limits of 222Rn and 226Ra activity concentrations are 100 Bq/dm3 and 0.5 Bq/dm3 respectively).