This study assesses the spatial distribution of naturally occurring radionuclides in soils surrounding the Siddirganj Combined Cycle Power Plant, Narayanganj, Bangladesh. Thirty soil samples were collected at radial distances of 100, 250, 500, 1000, and 1500 m from the facility and analyzed using high-purity germanium (HPGe) gamma-ray spectrometry to determine the activity concentrations of 226Ra,232Th, and 40K. The mean activity concentrations were 17 +/- 1, 31 +/- 3, and 329 +/- 27 Bq/kg, with observed ranges of 14-20, 21-41, and 260-400 Bq/kg, respectively. In general, the measured activities were below the worldwide average values of 30, 35, and 400 Bq/kg reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. Some spatial variability was observed among sampling distances; however, no systematic increase in radionuclide concentration was detected with proximity to the power plant, indicating that the distribution is primarily controlled by natural soil characteristics. Correspondingly, the calculated radiological hazard parameters, including absorbed dose rate and annual effective dose, remained within internationally accepted reference levels. These results suggest that the soils in the study area do not pose significant radiological risk under current environmental conditions and are suitable for typical land-use activities such as agriculture and construction. Nevertheless, periodic monitoring is recommended to support long-term environmental assessment.
The dipole hyperpolarizability ( gamma ) along with the dipole polarizability ( alpha ) of the spherically confined hydrogen atom under quantum plasmas are calculated quite accurately within the framework of the variation-perturbation method. The collective effect in a quantum plasma has been modeled by a pseudopotential in the form of exponential cosine screened Coulomb potential. Specifically, gamma and alpha are extracted from the variational expression of two definitive functionals which respectively correspond to the second order and fourth order corrections to the ground state energy of the confined hydrogen atom subject to the perturbation induced by the dipole moment operator. The stationary values of these variational functionals are evaluated with respect to a non-linear variational parameter by using two basis sets. Convergence of the results are corroborated by increasing the number of terms in the basis sets. An inclusive study is carried out to explore the changes emerging in gamma and alpha due to the variation of the spherical box as well as the quantum wave number.
Throughout the four seasons, 100 sediment samples (25 each season) were collected from Darbandikhan Lake. The specific activity of the artificial radioisotope Cs-137 was measured using a HPGe detector. The seasonally measured average activity concentration of Cs-137 radionuclide in sediment samples were (1.656 +/- 0.055, 1.634 +/- 0.055, 2.321 +/- 0.061 and 1.66 +/- 0.056) Bq kg(-1) in spring, summer, autumn and winter, respectively. These values are significantly lower than the recommended threshold of 10 Bq kg(-1) stated by UNCEAR (2000). Small variations in specific activity of this anthropogenic radionuclide were seen, ranging from below the minimum detection activity to a certain value during each season, except autumn in which some fluctuations have been observed in compare to other seasons. The ANOVA test shows a low F-statistic (0.69) and a high p-value (0.56), revealing a non-significant variation in Cs-137 sediment activity between seasons. The radiological parameters, including: absorbed dose, annual effective dose, and cancer risk associated with the activity of Cs-137, were evaluated for the studied sediment samples and all values are significantly below the recommended limits. The statistical analysis revealed that Cs-137 shows a strong positive correlation with Fe, Mn, and Ti. Conversely, Ca, P, Mg and Si display a weak negative correlation with Cs-137. The results show that the sediments of Darbandikhan Lake are safe from radiological contamination linked to Cs-137 pollution. These findings establish baseline data for tracking any future changes in Cs-137 levels.
