RADIOLOGICAL HAZARD INDICES OF GRANITIC ROCKS USED FOR THE CONSTRUCTION OF BUILDINGS FROM NUBA MOUNTAINS SUDAN

Assessment of the radiological health hazards around mine sites in Jos Area, Nigeria

Mining activities contribute to the accumulation of radionuclides, necessitating an assessment of the level of radioactivity around mine sites and the potential radiological hazards they pose to human health and the environment. This study assesses the radiological impacts of mining activities on the residents of selected mining areas at Rayfield, Gero, Sabongida Kanar, Kuru Jantar, Bisichi and Barkin Ladi in Jos Area, Nigeria. The activity concentration of 40K, 226Ra and 232Th in 24 mine wastes and 36 soil samples collected from farmlands adjoining the selected mine sites were determined by using a gamma-ray spectrometer fully equipped with an MPC 2000 radiation counter. This was done in accordance with the provisions of International Atomic Energy Agency (IAEA). Subsequently, the radiological hazard indices due to the radionuclides were evaluated following standard procedures. The mean activity concentrations of 40K, 226Ra and 232Th in both the mine waste and soil samples of the study area were found to exceed the global average terrestrial concentrations of 400, 35 and 40Bq/kg for 40K, 226Ra and 232Threspectively. The mean outdoor annual effective dose (OAED) for mine waste (7.6 ± 0.2 mS/yr) and soil samples (1.9 ± 0.04 mS/yr) was higher than the mean value of the control (1.46 ± 0.37) as well as the acceptable limits of 1 mS/yr for non-radiation workers, the world and Nigerian averages. Excess lifetime cancer risk (ELCR) values significantly exceed the global average of 0.52 × 10-3. The values of the hazard parameters like the radium equivalent activity (Raeq), OAED as well the ELCR were significantly higher than the recommended values and therefore pose considerable radiological hazard either on direct contact or being used as construction materials. The different hazard indices show a potential source of high radiological exposure. The findings indicate serious radiological health and environmental risks, requiring strict policy interventions, safer mining practices, remediation plans, and restrictions on the utilization of these mine wastes in construction and farming.

Natural Radioactivity of Granitic Rocks and Their Health Risk around Ingesana Mountains, Sudan

ABSTRACT

This work was carried out mainly to analyze radioactive elements 40 K, 232 Th, and 226 Ra and non-radioactive elements in some granitic rocks and study their health risk for humans and non-humans. Radioisotope activity was evaluated using a high-purity germanium (HPGe) detector, and various radiological hazard indices were calculated. We also measured some non-radioactive elements using x-ray fluorescence analysis and performed Pearson correlation analysis to examine the relationships between the radionuclides and the non-radioactive elements. Furthermore, we used the ERICA software to estimate the total dose rate per organism for some non-human biota. The means of 226 Ra, 232 Th, and 40 K are 25.13 ± 5.22 Bq kg -1 , 29.01 ± 6.95 Bq kg -1 , and 323.07 ± 97.83 Bq kg -1 , respectively. Hence, 226 Ra, 232 Th, and 40 K radioactivities were lower than the worldwide average limits. The 226 Ra, 232 Th, and 40 K levels were under the global average values. The hazardous radiometric variables were computed, and the findings observed that the mean absorbed dosage was 23.48 ± 7.36 nGy h -1 , the yearly effective dose rate was 29.82 ± 10.46 μSv y -1 , and the radium equivalent activity was 88.88 ± 18.64 Bq kg -1 . The average dose and yearly effective dose rates were lower than the global average absorbed dose rate of 60 nGy h -1 and the ICRP standard of 1.0 mSv y -1 . The results of Ra-equivalent activity were lower than the recommended maximum criterion for building materials limit of Ra-equivalent activity (370 Bq kg -1 ) proposed by UNSCEAR. Tests of Pearson correlation coefficients indicate a substantial positive relationship between 226 Ra and 232 Th and a modest correlation between 226 Ra and 40 K. Meanwhile, no association between 226 Ra and 40 K and non-radioactive components has been identified. Thorium-232 exhibits a moderately favorable connection with Ti, Fe, and Ni. The estimated total dose rate per organism for the studied non-human is less than the ambient dose rate. However, the total dose rate for small burrowing mammals and reptiles exceeds the background exposure rate. In accordance with the findings, granite rocks may be safe to use as construction materials and pose no threat to human health.

Radioactivity level evaluation in granite building raw material production area in Cenxi, China

This study was conducted to evaluate the radioactivity level in the granite building raw material production area in Cenxi, China. Natural radionuclide concentrations, γ absorbed dose rates (ADRs) and radon exhalation rates were measured in the area. The spatial distribution of natural radionuclides, γ ADR and radon exhalation rate were mapped with GPS information. The radioactivity levels in the study area were analysed based on the descriptive statistics and frequency distribution of measurement data. According to the Chinese standard, the granite raw materials used for building and decoration in this region were classified based on their radiological hazards. In addition, radiation protection measures were proposed for the mining of local granite building materials products as well as environmental protection around the work area and resident safety.

Health Hazards Assessment and Geochemistry of ElSibai-Abu ElTiyur Granites, Central Eastern Desert, Egypt

In this paper, a thorough radio- and chem-ecological evaluation of ElSibai-Abu ElTiyur granites located within Egypt’s crystalline basement rocks was conducted for risk and dose assessments. Twenty granitic samples from the study area’s various lithological units were analyzed using high-resolution γ-ray spectrometry to determine the natural radioisotopes (U-238, Th-232, and K-40) concentrations. The average concentrations of U-238, Th-232, and K-40 were 38.72, 38.23, and 860.71 Bq/kg, respectively, exceeding the GAV (global average value) documented by UNSCEAR (Scientific Committee on the Effects of Atomic Radiation, Vienna, Austria). The radiological parameters and indices judging the usage of ElSibai-Abu ElTiyur granites in homes were computed. The obtained results showed that ElSibai-Abu ElTiyur granites are safe to be used by inhabitants as superficial building materials, as per the globally accepted values and the recommended safety limits approved by UNSEAR, WHO (World Health Organization, Geneva, Switzerland), ICRP (International Commission on Radiological Protection, Ottawa, ON, Canada), and EC (European Commission, Luxembourg). Further, the samples were subjected to ICP-MS (inductively coupled plasma mass spectrometry) analysis for quantifying radionuclide variations with chemical composition. Geochemically based on the ICP-MS results, the studied granites proved to be highly evolved A-type granites. They span the metaluminous to peralkaline fields. The REE patterns are characterized by the enrichment of the light rare earths (LREE) over the heavy ones (HREE) where (La/Yb)n = 5.2, (Gd/Yb)n = 1.63 with pronounced negative Eu-anomalies (Eu/Eu*)n = 0.49. The albite granite exhibits the highest concentrations of Ga, Nb, Ta, U, and Y, and REE (Gd, Dy, Ho, Yb) than the Na-metasomatic granites. Finally, the obtained data serve as a valuable future database for finding out the compatibility of the geochemical data with the natural radioactivity levels of granites.

MONITORING AND CHARACTERISATION OF NEW EVIDENCE OF NATURAL RADIONUCLIDES IN ROCK OUTCROPS IN PARAÍBA-BRAZIL

The radiometric monitoring carried out in the present study allowed the discovery of anomalous granite outcrops in natural radionuclides in the rural area of São Mamede in the state of Paraíba, Brazil. The characterisation study made it possible to determine maximum specific concentrations of approximately 199 kBq kg-1 of 238U, 85 kBq kg-1 of 226Ra, 26 kBq kg-1 of 232Th and 24 kBq kg-1 of 40K. Models for environmental dosimetry were applied, which resulted in obtaining the following quantities: radium equivalent (Raeq), indices of external (Hex), internal (Hin) and representative (Iyr) damage, and the effective outdoor dose (HE). The maximum results presented were approximately 123 kBq kg-1, 332, 562, 832, and 68 mSv y-1, respectively. Consequently, it was possible to define the region as of high radioactive background due to isolated rocky outcrops located in the rural area of the mentioned municipality.

RADIOACTIVITY MEASUREMENT AND RADIOLOGICAL HAZARD ASSESSMENT OF THE COMMONLY USED GRANITE AND MARBLE IN JORDAN

Natural radioactivity of common commercial marble and granite types used in Jordanian dwellings are measured using high-resolution gamma spectrometry. The activity concentrations of 226Ra, 232Th and 40K ranged from 8.57 ± 1.55 to 152.07 ± 3.26 Bq kg-1, 6.83 ± 1.25 to 365.43 ± 4.84 Bq kg-1 and 121.25 ± 9.10 to 1604.90 ± 31.28 Bq kg-1 in granite and from 0.53 ± 0.12 to 18.61 ± 1.60 Bq kg-1, 0.51 ± 0.19 to 4.87 ± 2.13 Bq kg-1 and 3.21 ± 0.96 to 58.09 ± 6.40 Bq kg-1 in marble, respectively. Various radiological hazard indices like gamma index, internal and external hazard indices and annual effective dose equivalent were calculated and compared with the international limits. Our results show that some granite types may pose a radiation hazard.