Radiological characterization of beach sediments along the Alexandria–Rosetta coasts of Egypt

A comparative study of the elevated radioactivity in beach placer deposits of Bangladesh

Beach sediments are mineral deposits formed through weathering and erosion of either igneous or metamorphic rocks. Among the rock constituent minerals are some natural radionuclides that contribute to ionizing radiation exposure on Earth. Kolatoli and Kuakata are the two major beaches with heavy mineral deposits and important tourist sites in Bangladesh. Natural radioactivity in Kolatoli and Kuakata beach sand deposits along the southern coast of Bangladesh was assessed and compared to identify the sources, causes, and possible environmental impact. Result shows most of the radionuclides have higher activity concentrations than the background level, and the activity varies with the sample locations. The dominant radionuclides were found to be the radionuclides of thorium series i.e. Th-232 and Ra-228 followed by uranium series and K-40. The radioactivity in Kolatoli beach sands was observed to be much higher than Kuakata beach due to the presence of a higher content of heavy minerals i.e. illmenite, rutile, zircon, garnet and monazite. Furthermore, monazite and zircon are the two radioactive minerals that are considered to be the main contributors to the radioactivity in Kolatoli beach sand. These minerals are dominated by the activity of thorium series radionuclides i.e. Th-232 and Ra-228 surpass the activity of all other radionuclides such as U-238, U-234, Th-230, Ra-226, Po-210, and K-40. However, major contribution of radioactivity in Kuakata beach sand comes from uranium series radionuclides such as U-238, U-234, Ra-226, and Po-210. Beach morphology, sedimentological, and geochemical evolution of those minerals might be important areas of further study for the radioactivity monitoring activity in those areas.

Assessment of radiological indices and physiochemical characterization of sediments in Chashma Lake, Pakistan

Twenty surface sediment samples were gathered from Chasma Lake, deciding the radionuclides 137Cs, 226Ra, 228Ra, 232Th, and 40K and their associated hazard indices. The deliberate radionuclide activities of present research have been contrasted with earlier research, and acquired outcomes in the present study are found below the results in the world. The radiation hazard indices following the presence of natural radionuclides in sediment samples were estimated, and the results assigned the values of all the determined radiological indices found inside the worldwide suggested limits. It was concluded from the current review that the sediment of Chashma Lake is safe for construction and agriculture and does not make radiation dangerous to the nearby local area of the lake.

Radiological assessment in beach sediment of coastline, Ghana

The natural and artificial radioactivity in beach sediment sampled from the coastline of Ghana were analyzed using High Purity Germanium gamma ray detector. The overall average activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs were estimated to be 43 ± 6, 22 ± 1, 393 ± 74 and 8.4 ± 0.5 Bqkg^-1, respectively. Apart from ²²⁶Ra the mean activity concentrations of the measured radionuclides were below the world averages of 32, 45, 412 and 18.2 Bqkg^-1 respectively. High ¹³⁷Cs mean concentration of 109.8 Bqkg^-1 was observed for one of the locations, which might be due to the occurrence of a nuclear incidence or other factors. The evaluated radiological parameters also had values below world averages, except for some coastal areas which recorded Annual Gonadal Dose Equivalent (AGDE) values higher than the reference level of 300 μSvy^-1. There was no significant risk associated with the radionuclide activities evaluated along the coast of Ghana. The correlation between the radionuclides and the radiological parameters were analyzed with the Pearson correlation matrix, cluster and PCA analysis, and they all showed similar outcomes. Spatial distribution maps were also created using ArcGIS software for a pictorial view of the distribution of radionuclides along the study area.

RADIOACTIVITY ASSESSMENT OF SURFACE SOIL IN THE VICINITY OF A URANIUM MINE IN MALAWI

The activity concentrations of 238U, 232Th and 40K in the soil of areas surrounding the Kayelekera uranium mine were assessed. This study aims to provide a comprehensive profile of soil radioactivity distribution in the area surrounding the uranium mine to determine radiological hazards associated with mining and processing activities. Soil samples were analysed using gamma-ray spectrometry with a high-purity germanium detector. Mean specific activities of 238U, 232Th and 40K were 58.3 ± 3.7, 40.3 ± 0.3 and 590.9 ± 63.9 Bq kg-1, respectively. Results from this study have indicated changes in radioactivity levels of naturally occurring radioactive materials in the area surrounding the understudied mine, with certain areas close to the mine site showing elevated levels of 238U, highlighting the need for systematic and periodic monitoring.

Radiological risk assessment in sediment of Namal Lake, Mianwali, Pakistan

This study is concentrated on the radiological risk assessment of sixteen surface sediment samples recovered from Namal Lake, District Mianwali, Punjab, Pakistan. The activity of ¹³⁷Cs, ⁴⁰ K, ²²⁶Ra, ²²⁸Ra, and ²³²Th was carried out with the help of a high purity germanium detector (HPGe) in the sediment, varied in the ranges of > 0.02-3.73 ± 1.31, 98.32 ± 21.45-341.02 ± 58.67, 18.34 ± 2.16-34.23 ± 4.34, 1.62 ± .30-2.34 ± .52, and 0.14 ± 0.10-2.34 ± 0.59 Bq kg^-1 with average values 0.74 ± 0.29, 237.26 ± 37.97, 25.06 ± 4.74, 1.97 ± 0.39, and 1.73 ± 0.33 Bq kg^-1, respectively. The measured concentrations in the current study have been compared with other earlier studies in the world. The data was also used for determining the other useful parameters like radium equivalent activity, absorbed dose rate, annual effective dose rate, and external and internal hazards index to assess the radiological risk assessment for the environment around the study area. The ERICA Tool software was also applied for radiological risk assessment for lake fish due to the radioactivity present in the lake sediments. It was concluded from the results of ERICA tool that the risk quotient in this study is less than one indicating that no toxic effects of radioactivity for Namal Lake fish.

Assessment of radioactivity concentration in intertidal sediments from coastal provinces in Oman and estimation of hazard and radiation indices

The natural radioactivity of intertidal sediment samples collected from the beaches of Oman was investigated. Using gamma ray spectrometry, the activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the sediment samples were measured to have average values of 20.49 ± 3.50, 2.26 ± 0.60 and 44.83 ± 4.60 Bq kg^-1 respectively. The activity levels reported are considerably lower than the worldwide average. The annual effective dose rate was estimated to be 0.015 mSv yr^-1 on average. Additionally, the mean radium equivalent, external and internal indices were 26.89, 0.07 and 0.13 Bq kg^-1 respectively which were well below the risk limits. Gamma and alpha radiation indices were computed to be less than unity and show no exceedance beyond the recommended level. Our results provide baseline data for radioactivity in intertidal sediment samples of Oman and show that intertidal beach sand does not pose significant radiological risk to human health.

A seasonal 222Rn mass-balance of Lake Burullus, Egypt: Indications for higher pore water exchange rates during the dry season

Radon mass balances in lakes can be used to trace transport processes along the sediment-water interface, such as groundwater discharge or pore water exchange. Understanding these transport processes is important, as they can affect the lake water budget, or biogeochemical cycles in lakes due to nutrient inputs. We present here a seasonal ²²²Rn mass balance of Lake Burullus (Northern Egypt), the second largest lake of Egypt. The Lake receives ²²²Rn from drainage water and the decay of ²²⁶Ra, and loses ²²²Rn via decay of ²²²Rn, atmospheric evasion and water discharge into the Mediterranean Sea. However, the mass balance reveals a significant surplus of ²²²Rn, which cannot be explained by the previously mentioned processes. The ²²²Rn surplus is especially high during the dry season, and might be explained by groundwater discharge and pore water exchange which transports ²²²Rn into the lake. Higher ²²²Rn fluxes into the lake during dry season might be explained by higher bioirrigation rates due to warmer temperatures, or higher groundwater discharge rates due to a higher hydraulic head on land caused by excessive irrigation in adjacent fields. Groundwater discharge and pore water exchange should be investigated in further detail in order to understand if they have effects on water budgets and biogeochemical cycles of Lake Burullus.