Analysis of radionuclides and radiation hazards in soil, sediment, water, and rock in Sylhet, Bangladesh.

This article focuses on measuring natural radioactivity levels in soil, sediment, water, and rock samples from the Bisnakandi, Bholagonj, and Jaflong regions in Sylhet District, northeastern Bangladesh, using gamma spectrometry with a high-purity germanium detector. The study quantified activity concentrations of naturally occurring radionuclides Thorium-232 (^232Th), Radium-226 (^226Ra), and Potassium-40 (^40K), finding all radiological hazard parameters—including radium equivalent activity, absorbed dose rate, annual effective dose, external hazard index, and excess lifetime cancer risk—within internationally accepted safety limits. No significant presence of artificial radionuclide Cesium-137 (^137Cs) was detected, indicating minimal anthropogenic contamination. The results suggest low-level radiation exposure for local inhabitants and provide baseline data useful for future environmental monitoring, especially in light of Bangladesh's upcoming nuclear power developments.