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Abstract Yellow ochre is the basic material used in the manufacture of yellow oxide (a commercial product). Yellow ochre samples were taken from three different formations in southwestern Sinai: Abu Hamata, Um Bogma, and Abu Zarab. Yellow ochre occasionally exists in Abu Hamata Formation particularly in El Ferah area, associated with Fe–Mn ore in Wadi El Sahu (Um Bogma Formation) and in Himayer area (Abu Zarab Formation). The XRD analysis of the raw material reveals that they are mainly composed of goethite, which is associated with quartz and kaolinite in El Ferah area, hematite, kaolinite and quartz in Himayer area, and kaolinite, gypsum and quartz in Wadi El Sahu. The commercial product is mainly composed of goethite, quartz, and calcite. The heavy mineral investigation shows that some yellow ochre samples contain zircon and rare earth sulfate which may be responsible for the radioactivity of ochre due to their thorium and uranium content. The average values of specific radio-activities of most radionuclides in the samples of Himayer area I and II, and El Sahu I are higher than the respective world averages, while their activities are lower in El Ferah and El Sahu II. Th/U and Ra/U ratios exhibit vigorous changes in physico-chemical conditions during uranium leaching and deposition. Most of the radiological parameters in the ferruginous sediment and commercial product samples from El Ferah, El Sahu II, and Himayer II are lower than the recommended international values but higher than those from Himayer I and El Sahu I samples. The plotted hierarchical cluster analysis (HCA) exhibits that the main contributors for the hazards of these sediments and their commercial product are 238U, 232Th and 226Ra in Himayer I &II, commercial products, and El Ferah area, 232Th and 226Ra in El Sahu II , 232Th, 40K and 226Ra in El Sahu I.

Yellow ochre is the basic material used in the manufacture of yellow oxide (a commercial product). Yellow ochre samples were taken from three different formations in southwestern Sinai: Abu Hamata, Um Bogma, and Abu Zarab. Yellow ochre occasionally exists in Abu Hamata Formation particularly in El Ferah area, associated with Fe–Mn ore in Wadi El Sahu (Um Bogma Formation) and in Himayer area (Abu Zarab Formation). The XRD analysis of the raw material reveals that they are mainly composed of goethite, which is associated with quartz and kaolinite in El Ferah area, hematite, kaolinite and quartz in Himayer area, and kaolinite, gypsum and quartz in Wadi El Sahu. The commercial product is mainly composed of goethite, quartz, and calcite. The heavy mineral investigation shows that some yellow ochre samples contain zircon and rare earth sulfate which may be responsible for the radioactivity of ochre due to their thorium and uranium content. The average values of specific radio-activities of most radionuclides in the samples of Himayer area I and II, and El Sahu I are higher than the respective world averages, while their activities are lower in El Ferah and El Sahu II. Th/U and Ra/U ratios exhibit vigorous changes in physico-chemical conditions during uranium leaching and deposition. Most of the radiological parameters in the ferruginous sediment and commercial product samples from El Ferah, El Sahu II, and Himayer II are lower than the recommended international values but higher than those from Himayer I and El Sahu I samples. The plotted hierarchical cluster analysis (HCA) exhibits that the main contributors for the hazards of these sediments and their commercial product are 238U, 232Th and 226Ra in Himayer I &II, commercial products, and El Ferah area, 232Th and 226Ra in El Sahu II , 232Th, 40K and 226Ra in El Sahu I. [ABSTRACT FROM AUTHOR]

ObjectivesModel prediction of radioactivity levels around nuclear facilities is a useful tool for assessing human health risks and environmental impacts. We aim to develop a model for forecasting radioactivity levels in the environment and food around the world’s first AP 1000 nuclear power unit.MethodsIn this work, we report a pilot study using time-series radioactivity monitoring data to establish Autoregressive Integrated Moving Average (ARIMA) models for predicting radioactivity levels. The models were screened by Bayesian Information Criterion (BIC), and the model accuracy was evaluated by mean absolute percentage error (MAPE).ResultsThe optimal models, ARIMA (0, 0, 0) × (0, 1, 1)4, and ARIMA (4, 0, 1) were used to predict activity concentrations of 90Sr in food and cumulative ambient dose (CAD), respectively. From the first quarter (Q1) to the fourth quarter (Q4) of 2023, the predicted values of 90Sr in food and CAD were 0.067–0.77 Bq/kg, and 0.055–0.133 mSv, respectively. The model prediction results were in good agreement with the observation values, with MAPEs of 21.4 and 22.4%, respectively. From Q1 to Q4 of 2024, the predicted values of 90Sr in food and CAD were 0.067–0.77 Bq/kg and 0.067–0.129 mSv, respectively, which were comparable to values reported elsewhere.ConclusionThe ARIMA models developed in this study showed good short-term predictability, and can be used for dynamic analysis and prediction of radioactivity levels in environment and food around Sanmen Nuclear Power Plant.

ObjectivesRadioactivity monitoring around nuclear facilities is crucial to provide important baseline data for effective detection of radioactive leakage to the environment. We aim to establish a baseline study for monitoring radioactive levels of 90Sr and 137Cs around Sammen Nuclear Power Plant (SNPP) and to assess their associated health impact on surrounding residents.MethodsIn this study, we collected water and food samples around the SNPP from 2011 to 2020 and determined for 90Sr and 137Cs activity concentrations. We statistically analyzed the temporal trends of 90Sr and 137Cs and evaluated their radiation exposure to the local residents.ResultsDuring this period, the activity concentrations of 90Sr and 137Cs varied within 1.2–9.9 mBq/L and 0.10–7.6 mBq/L in water, and 0.037–1.3 Bq/kg and 0.011–0.45 Bq/kg in food, respectively, with no significant seasonal variation trend.ConclusionsAll reported activity concentrations of 90Sr and 137Cs were significantly lower than the recommended value of WHO and Chinese national standards. There is no indication of notable radioactive release into the study area due to the operation of SNPP during 2018–2020. The annual effective doses (AEDs) from the ingestion of 90Sr and 137Cs in water and food were well below the international permissible limits, indicating the radiation exposure around SNPP during 2011–2020 was kept at a safe level.

Groundwater may contain radioactive substances which can be dangerous to human health. Concentrations of natural radionuclides polonium (Po), thorium (Th), uranium (U), and radium (Ra) isotopes were measured in groundwater samples collected from different locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, New Mexico. The average values of gross activity concentrations of 210Po, 228Th, 238U, 234U, 226Ra and 228 Ra isotopes were determined to be 1.62 Bq L-1 in shallow groundwater and 5.88 Bq L-1 in deep groundwater, respectively. The total radioactivity in deep groundwater was higher than that in shallow groundwater, and most of the radioactivity in the water is from 226Ra. Furthermore, the effective doses for ingestion of natural radionuclides were about 0.333 mSv y−1 for shallow groundwater and about 1.338 mSv y−1 for deep groundwater samples, which are higher than the World Health Organization (WHO, 2017) guideline level (0.1 mSv y−1) for drinking water. Ra dominated the total ingestion dose, contributing 93.06 % and 75.40 % of the total effective doses to the deep and shallow groundwater, respectively. The ingrowth and decay of natural radionuclides suggested that 228Ra/226Ra ratio can be a useful indicator of the source of radioactive contamination. The radioactivity data obtained from the investigated groundwater samples can be used to establish a baseline for radioactivity levels in groundwater around the WIPP site.

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration (Ac), minimum detectable activity, absorbed gamma dose rate, external hazard index (Hex), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index (Hex and Hin, respectively) were estimated based on the measured radionuclide concentration of the 238U(226Ra) and 232Th decay chains and 40K. The activity concentrations of the 238U, 232Th decay series and 40K of these samples varied from 45.11 ± 3.1 Bq/kg to 252.38 ± 34.3 Bq/kg, from 64.65 ± 6.1 Bq/kg to 579.84 ± 53.1 Bq/kg, and from 403.36 ± 20.8 Bq/kg to 527.47 ± 23.1 Bq/kg, respectively. The activity concentration of 232Th in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from 99.86 μSv/y to 612.31 μSv/y, which are higher than the world average values of 59 nGy/h and 70 μSv/y, respectively. The Hex values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of Hex for Sample 1 is significantly higher than the international acceptable limit of

Groundwater may contain radioactive substances which can be dangerous to human health. Concentrations of natural radionuclides polonium (Po), thorium (Th), uranium (U), and radium (Ra) isotopes were measured in groundwater samples collected from different locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, New Mexico. The average values of gross activity concentrations of 210Po, 228Th, 238U, 234U, 226Ra and 228 Ra isotopes were determined to be 1.62 Bq L-1 in shallow groundwater and 5.88 Bq L-1 in deep groundwater, respectively. The total radioactivity in deep groundwater was higher than that in shallow groundwater, and most of the radioactivity in the water is from 226Ra. Furthermore, the effective doses for ingestion of natural radionuclides were about 0.333 mSv y−1 for shallow groundwater and about 1.338 mSv y−1 for deep groundwater samples, which are higher than the World Health Organization (WHO, 2017) guideline level (0.1 mSv y−1) for drinking water. Ra dominated the total ingestion dose, contributing 93.06 % and 75.40 % of the total effective doses to the deep and shallow groundwater, respectively. The ingrowth and decay of natural radionuclides suggested that 228Ra/226Ra ratio can be a useful indicator of the source of radioactive contamination. The radioactivity data obtained from the investigated groundwater samples can be used to establish a baseline for radioactivity levels in groundwater around the WIPP site. • Deep groundwater has higher radium radioactivity and salinity than shallow groundwater. • The radioactivity in groundwater is most likely from natural resources. • Monitoring of trends of groundwater radioactivity levels at the Waste Isolation Pilot Plant is needed. • Radium is the major contributor to the total effective doses for groundwater. • Total effective doses for groundwater exceed the WHO limit level for drinking water. [ABSTRACT FROM AUTHOR]