Natural radioactivity and its radiological implications from soils and rocks in Jaintiapur area, North-east Bangladesh

Determination of natural radioactivity levels in soil samples from irrigated vegetable farming land in and around Addis Ababa, Ethiopia

Soil samples were collected from vegetable agricultural areas in and around Addis Ababa, and their levels of radioactivity were measured. Gamma spectrometry with high-purity germanium detector was used to quantify radioactivity level. The average concentration of 226Ra, 232Th, and 40K were 32.8 ± 2.1, 62.4 ± 4.4, and 544.3 ± 23.3 Bq kg-1 respectively. The mean values of 232Th and 40K are higher, whereas the value of 226Ra is comparable with world average values. Radiological hazard indices, including radium equivalent activity (Raeq), absorbed dose rate (Dr), outdoor annual effective dose equivalent (Deff), external hazard index (Hex), internal hazard index (Hin), and gamma radiation representative level index (Iγ), were calculated based on the activity concentration of 226Ra, 232Th and 40K. The mean values were 163.9 Bq kg-1, 78.7 nGy h-1, 0.10 mSv y-1, 0.44, 0.53, and 0.60 respectively. All indices are lower than global recommended limit values. These results revealed that radiation hazard due to radionuclides in the soil of the study area is insignificant.

Evaluation of the potentially toxic elements and radionuclides in the soil sample of Novaya Zemlya in the Arctic Circle

The study presented here elucidate the concentrations of radionuclides and potentially toxic elements in the soil samples around the Novaya Zemlya in the Russian Arctic zone, determined using HPGe gamma spectrometry, inductively coupled plasma optical emission spectrometry and direct mercury analyzer. The average detected concentrations for 226Ra, 232Th, 40K, 235U and 137Cs were 36.40, 46.06, 768, 2.06 and 4.71 Bq/kg, respectively. At many sampling sites, the concentrations of potentially toxic elements (Zn, Cu, Pb, Cd, Ni, and Cr) were higher than the natural levels. Positive Matrix Factorization analysis revealed the contribution of oil dumps (32%), natural sources (16%), bird colonies (32%) and atmospheric deposition (20%) for elevated elements content. In the case of radionuclides, the natural occurring contamination (38%) was primary source followed by dumped material (32%) and bird colonies (30%). The radiological risk from radionuclides was relatively high, yet still under permissible levels. For potentially toxic elements, Fe was predominant non-carcinogenic pollutant and Ni emerged as major carcinogenic contaminant. Keeping in view the high content of some elements, future studies are required to keep the human and ecological risk low, and to establish scientific grounds for the contribution of settled bird species. The findings of the study advance the present knowledge about the contamination of the study area and lays the path for further effort.

A review of the occurrence of naturally occurring radioactive materials and radiological risk assessment in South African soils

According to reports, exposure to high concentrations of naturally occurring radioactive substances like Uranium-238, Thorium-232, and Potassium-40 poses serious health concerns. This review study aims to report the concentrations of radionuclides in various South African soil and their equivalent risk assessments, which have been sparingly reported. For South Africa, most radionuclide concentrations above the permissible limits of 33, 45, and 420 Bq.kg-1 for 238U, 232Th, and 40K, respectively, have been found in some soil samples taken near industrialization activities, including mining and oil exploration and production. Thus, the amount of radionuclides is a good indicator of the kind of soil, the local geology, and the mineral make-up of the parent rocks. The increases in radiation exposure to people and the environment have been reported to cause various radiological health hazards. Thus, this review study can be used as a data source to track probable radioactive contamination from soils found in South Africa.

Statistical assessment of natural radioactivity, radon activity, and associated radiological exposure due to artisanal mining in Atiwa West district of the Eastern region, Ghana

The activity concentration of natural radionuclides, radon activity concentration, mass and area exhalation rates have been studied in soils from gold mining communities in Atiwa West district. The natural radionuclides were determined by gamma ray spectrometry method while radon concentrations were measured using CR-39 detectors. The mean activity concentrations were found to be 26.9 ± 1.7 Bq/kg, 57.5 ± 3.6 Bq/kg, 237.5 ± 17.6 Bq/kg and 560.0 ± 54 Bq/m3 for Ra-226, Th-232, K-40 and Rn-222 respectively. The evaluated mass exhalation rates ranged from 2.8 ± 0.3 to 6.5 ± 0.7 × 10-5 Bq/kg/h while the area exhalation rates were from 0.8 ± 0.09 to 2.0 ± 0.21 × 10-3 Bq/m2/h. Some mining and farming areas recorded high exhalation rates indicating that the use of soils as building materials from such areas could pose a level of radiation hazard to the population. The evaluated radiological risks were below reference levels. A good linear correlation was observed between Ra-226 and Rn-222 activity concentrations and in the investigated soils. The Pearson correlation coefficient, cluster analysis and principal component analysis were used to study the relationship between the determined parameters of the study.

Assessment of radioactivity level and associated radiological hazard in riverbed samples within industrial areas

Terrestrial gamma radiation is one of the major outdoor radiation exposures to the general public that varies substantially based on the type and geological properties of the soil. The objective of this study is to evaluate the naturally occurring radioactive materials (NORMs) distribution and assess the hazard parameters in the riverbank soil within various industrial zones in the densely populated Dhaka and Chattogram cities of Bangladesh. The mean activities of 226Ra (37 ± 3), 232Th (58 ± 4), and 40K (1129 ± 18) Bqkg-1 in the assessed soil samples were found to be slightly higher than the world average values 32, 35, and 420 Bqkg-1, respectively. The mean radium equivalent activity (207.49 Bqkg-1) and the external and internal hazard indices were within the recommended limits of 370 Bqkg-1 and <1, respectively. The mean absorbed dose rate (99.47 nGyhr-1), annual effective dose (0.12 mSva-1), ELCR (4.27 × 10-4), and gamma level index (1.58) exceeded the world average values 59 nGyhr-1, 0.07 mSva-1, 2.9 × 10-4, and 1 respectively. However, the studied areas are safe from a radiological viewpoint with no radiation health hazard to the people. The results of this study can be utilized to produce factual baseline data for future studies.

Toxicity risks associated with heavy metals to fish species in the Transboundary River - Linked Ramsar Conservation Site of Tanguar Haor, Bangladesh

The presence of trace metals in aquatic ecosystems can have detrimental effects on fish survival. The Tanguar haor, a Ramsar conservation wetland, receives sediment and water from multiple transboundary rivers. However, there have been limited studies on the metal concentrations in fish species in this sediment-rich wetland. This study aimed to analyze the concentrations of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in water, sediment, and fish tissues. Higher concentrations of Cd and Pb were found in the water and sediment. All these metals were detected in eight fish species, including benthic and pelagic species. Among them, Systomus sarana, a pelagic fish that also consumes benthic organisms, exhibited a higher metal pollution index than other fish, particularly benthic species. The release of higher metal concentrations from sediment into the water has the potential to impact the accumulation of metals in fish. SYNOPSIS: This study on metal concentrations in fish species will aid policymaking on ecotoxicology research for transboundary river-connected wetlands.

Assessment of natural radioactivity, radon gas and soil characteristics along the Volta Lake in the Kpando municipality of Volta region, Ghana

Assessment of radionuclides, indoor radon (222RnI), radon exhalation (222Rnex), and soil characteristics in the coastal part of Kpando has been studied using HPGe, CR-39 and sieving techniques. Statistical analysis between radionuclides, radon levels and soil characteristics was done using Pearson's correlation. The mean radionuclide concentration, radon levels and soil characteristics were obtained as 226Ra (23.1 ± 1.4 Bq per kg), 232Th (34.6 ± 2.9 Bq per kg), 40K (187.1 ± 13.7 Bq per kg), 222RnI (64.70 ± 2.7 Bq per m3), 222Rnex (7.9 ± 0.5 μBq per m2h), sandy (45.9 ± 3.9%), silt (40.7 ± 3.1%), clay (13.5 ± 0.8%), porosity (0.6 ± 0.1) and moisture (7.6 ± 0.8%). Radiological effects estimated were within recommended limits. The maximum positive and negative coefficients exist between 222Ra/222Rnex (1.0) and 222Rnex/MC (-0.9), respectively. Radon exhalation correlates better with soil characteristics. The statistical analysis indicated that soil characteristics have significant effects on radionuclides and radon levels in soils and dwellings.

Natural radioactivity in soil samples taken from Kahramanmaraş provincial center

The levels of ²³⁸U, ²³²Th, and ⁴⁰K with gross alpha and beta values in soils collected from the Kahramanmaraş city center were measured in this study, and the annual effective dose equivalent (AEDE), excessive lifetime cancer risk (ELCR), and terrestrial absorbed gamma dose rates were calculated for gamma radiation from ²³⁸U, ²³²Th, and ⁴⁰K radionuclides. The samples' gross alpha and beta radioactivity concentrations, respectively, range from 0.06 ± 0.01 Bq/kg to 0.45 ± 0.04 Bq/kg and 0.14 ± 0.02 Bq/kg to 0.95 ± 0.09 Bq/kg. The Kahramanmaraş province's soil samples have mean gross alpha and beta radiation values of 0.25 ± 0.03 Bq/kg and 0.52 ± 0.05 Bq/kg, respectively. ²³⁸U, ²³²Th, and ⁴⁰K activity concentrations in soil samples range from 2.32 ± 0.2 Bq/kg to 40.10 ± 1.4 Bq/kg, 0.60 ± 0.03 Bq/kg to 10.47 ± 1.01 Bq/kg, and 11.60 ± 1.01 Bq/kg to 160.84 ± 4.6 Bq/kg, respectively. ²³⁸U, ²³²Th, and ⁴⁰K each had average activity concentrations of 11.50 ± 1.1, 4.50 ± 0.4, and 62.20 ± 1.6 Bq/kg in soil, respectively. The annual effective dose equivalent (AEDE), excessive lifetime cancer risk (ELCR), and terrestrial absorbed gamma dose rate range from 0.01 ± 0.01 μSv y^-1 to 0.03 ± 0.02 μSv y^-1, and 0.01 ± 0.01 × 10^-3 to 0.12 ± 0.03 × 10^-3, 1.72 ± 0.01 nGy h^-1 to 25.05 ± 0.21 nGy h^-1, respectively. Additionally, the average annual effective dose equivalent (AEDE), average excessive lifetime cancer risk (ELCR), and average terrestrial absorbed gamma dose rates are 0.01 ± 0.01 μSv y^-1, and 0.05 ± 0.02 × 10^-3, 9.81 ± 0.09 nGy h^-1, respectively. The acquired data were compared to both domestic and international standards.