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.

Cell-cycle dependence on the biological effects of boron neutron capture therapy and its modification by polyvinyl alcohol.

Boron neutron capture therapy (BNCT) is a unique radiotherapy of selectively eradicating tumor cells using boron compounds (e.g., 4-borono-L-phenylalanine [BPA]) that are heterogeneously taken up at the cellular level. Such heterogenicity potentially reduces the curative efficiency. However, the effects of temporospatial heterogenicity on cell killing remain unclear. With the technical combination of radiation track detector and biophysical simulations, this study revealed the cell cycle-dependent heterogenicity of BPA uptake and subsequent biological effects of BNCT on HeLa cells expressing fluorescent ubiquitination-based cell cycle indicators, as well as the modification effects of polyvinyl alcohol (PVA). The results showed that the BPA concentration in the S/G2/M phase was higher than that in the G1/S phase and that PVA enhances the biological effects both by improving the uptake and by canceling the heterogenicity. These findings might contribute to a maximization of therapeutic efficacy when BNCT is combined with PVA and/or cell cycle-specific anticancer agents.

Assessment of radiological risk associated with thoron gas at primary schools in Al-Najaf city, Iraq.

Children spend considerable time at home and school, so school is likely to be a second source of natural radionuclide exposure after home. This study evaluates the radiological risk associated with thoron gas in the air within the building of one hundred primary schools in Al-Najaf City, Iraq, using a CR-39 detector. The results of the average value of thoron concentration detector, the annual effective dose (AED), Excessive Lifetime Cancer Risk (ELCR) × 10-3, and Lung Cancer Case (LCC) × 10-9 measured in the building of the schools were 7.47 ± 2.85 Bq/m3, 0.03 ± 0.01 mSv/y, 0.11 ± 0.04, and 0.54 ± 0.20, respectively. All the results of indoor thoron were below the global average limit. The results of the radiological survey due to thoron concentrations for studied primary schools suggest that the radionuclides and their radiological hazard indexes in all studied schools in AL Najaf city, Iraq, do not impose a health hazard.