Evaluation of environmental radioactivity in soils around a coal burning power plant and a coal mining area in Barapukuria, Bangladesh: Radiological risks assessment

To study the distributions and potential dispersions of naturally occurring radioactive materials (NORMs: Ra-226, Th-232, and K-40) from coal-based activities (Barapukuria, Bangladesh), we studied a suite of systematically collected surface and sub-surface soil samples by X-ray fluorescence and high purity germanium detector based gamma-spectroscopy. The average (range) radioactivities of Ra-226, Th-232, and K-40 in the studied soil samples were 80.6 (33.0-118.0), 104.4 (43.0-182.0), and 508.1 (318.3-743.4) Bq.kg(-1), respectively, which are significantly higher than the corresponding world average value. No significant fractionations of NORMs were observed between the surface and sub-surface soils, except for Th-232. Along with the anthropogenic origin, several geochemical processes (e.g., weathering, mineralogical dissolution/precipitation, alteration, leaching, differential solubility mediated geochemical mobility etc.) play significant role in NORM distributions. Major-oxide abundances, indices-based calculations, and correlation studies on the measured parameters revealed the natural processes (e. g., geochemical mobility, mineralogical distributions, water logging based differential solubility) responsible for NORM distributions. In terms of mean radium equivalent activity, internal hazard index, and total annual effective dose values, the studied area possesses trivial radiological risks, whereas the values of internal absorbed gamma dose and excess lifetime cancer risk demonstrate significant health hazards. Considering the adverse radiological risks originating from coal-based industrial activities and the long half-lives of NORMs, the present scenario will potentially be deteriorated.

Automated summary

This study investigates the distributions and potential dispersions of naturally occurring radioactive materials (NORMs: Ra-226, Th-232, and K-40) from coal-based activities in Barapukuria, Bangladesh. The results show that the radioactivities of NORMs in the studied soil samples are significantly higher than the world average value. The distribution of NORMs is influenced by both natural processes and anthropogenic activities. The radiological risks in the studied area are relatively low in terms of certain parameters, but significant health hazards are indicated by other parameters.