Radionuclides distribution and radiation hazards assessment of black sand separation plant's minerals: a case study

This study assessed the radioactivity levels and associated risks in the black sand-separated products obtained from the black sand separation plant in Delta, Egypt. A total of sixteen samples were taken from hot spots during and after the separation process. These include water samples and other samples that represent monazite, rutile, zircon, granite, ilmenite, and silica products. The hot spots included the area where the ore was stored. The activity concentrations of232 T h ,226 R a , and40 K were determined in these samples using a p-type HPGe detector. Based on gamma spectrometric analysis, samples of rutile, zircon, and monazite had the highest amounts of radioactivity because they contained the highest NORM's activity concentrations. In addition, it indicated that the radiological hazard indices of the collected samples were higher than the average world limits for sand texture. These findings suggest that the black sand separation process reveals potential risks to human health and the environment, and therefore, appropriate measures need to be taken to mitigate these risks, especially for the safety of the workers on-site. Reducing the risk associated with those sites should be controlled by implementing the recommendations declared for the series of International Basic Safety Standards of the International Atomic Energy Agency (GSR) Part 3, as affirmed in Document No. 103 of 2007 by the International Commission on Radiological Protection (ICRP) as will be presented in the paper body.

Environmental assessment of radionuclides levels and some heavy metals pollution along Gulf of Suez, Egypt

This work aims to evaluate radioactivity levels of 238U (²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K and the associated radiological hazard indices, as well as to assess the current status and concentrations of heavy metals along the coastline of the Gulf of Suez, in order to identify potential sources of contamination and to construct radioactivity baseline for this area. Measurements of the activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K in Bq kg^-1 of the collected samples were carried out using high-purity germanium (HPGe) detector. Heavy metals in seawater, shore sediment, and algae samples were determined using ICP-OES. The average activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K were found to be 13.79 ± 0.75, 14.57 ± 1.15, and 128.9 ± 4.15 Bq kg^-1, respectively. The radiological hazard indices of absorbed dose rate in nGy h^-1 (D), annual effective dose rate in mSv y^-1, AED, radium equivalent activity in Bq (Ra_eq), external and internal hazard indices (H_ex, H_in), and cancer risk factor were calculated and compared with the worldwide averages. The distribution patterns of annual effective dose (AED) at the Suez Gulf showed that the south east of the Gulf is characterized by higher AED. Water quality parameters (water temperature, salinity, pH, DO, and Eh) reveal that Suez Gulf was undoubtedly affected by the rate of the human activities. Heavy metal concentrations in shore sediments showed some variation within the study area and followed the following order: Fe > Mn > Zn > Al > B > Co > Ni > Pb > V > Cr > Mo > Cu > Cd. Furthermore, heavy metal concentrations indicated that northern part of the Gulf contains the highest levels of these metals compared to the southern one.

Assessment of natural radioactivity in coals and coal combustion residues from a coal-based thermoelectric plant in Bangladesh: implications for radiological health hazards

To study the level of radioactivity concentrations from a coal-based power plant (Barapukuria, Bangladesh) and to estimate the associated radiological hazards, coal and associated combustion residuals from the power plant were analyzed by gamma-ray spectrometry with high-purity germanium (HPGe) detector. The results reveal that the mean radioactivity (Bq kg^-1) concentrations in feed coal samples are 66.5 ± 24.2, 41.7 ± 18.2, 62.5 ± 26.3, and 232.4 ± 227.2 for U-238, Ra-226, Th-232, and K-40, respectively, while in coal combustion residuals (CCRs), they are 206.3 ± 72.4, 140.5 ± 28.4, 201.7 ± 44.7, and 232.5 ± 43.8, respectively. With the exception of K-40, all the determined natural radionuclides are considerably higher in the investigated feed coal and associated combustion residues as compared with the world soil and world coal mean activities. On the average, CCRs contains 3.10-3.37 times more natural radionuclides than the feed coal, except for K-40. The radioactivity of fly ash and bottom ash is fractionated, and ratio ranges from 1.40 to 1.57. The mean values of the radiological hazard indices in the coal and their associated residuals are 153.1 and 446.8 Bq kg^-1 for radium equivalent activity, 0.41 and 1.21 for the external hazard index, 70 and 200.1 nGy h^-1 for the absorbed gamma dose rate, 0.09 and 0.25 mSv year^-1 for the annual effective dose rate, and 3.0 × 10^-4 and 8.6 × 10^-4 Sv^-1 for the excess lifetime cancer risk, respectively, most of which exceed the UNSCEAR-recommended respective threshold limits. The outcome of this study suggests a potential radiological threat to the environment as well as to the health of occupational workers and nearby inhabitants from the examined samples.