Spatial distribution of radionuclides in agricultural soil in the vicinity of a coal-fired brick kiln

The spatial distributions of naturally occurring radionuclides (Ra-226, Th-232, and K-40) in agricultural soils collected in the proximity of a coal-fired brick kiln located at Chittagong district were studied using HPGe -ray spectrometry. The obtained mean activity concentrations for Ra-226, Th-232, and K-40 were slightly higher than the world average values, which indicate the contribution of radionuclides via the fly ash deposition from the kiln. The maximum activity concentrations of Ra-226, Th-232, and K-40 in soil samples collected at a distance of 120m from the kiln were found to be 54.3 +/- 11.3Bqkg(-1), 62.1 +/- 18.2Bqkg(-1), and 572 +/- 123Bqkg(-1), respectively; the levels show further decreasing trend in all directions (towards and away from the kiln). Associated radiological hazard indices were calculated in order to assess the radiation effects to human health and compared with the world-recommended values. Basic multivariate statistical analysis was performed to describe the statistical characteristics of the radionuclides. Lower values of radiological indices indicate that there is no probability of immediate health effect on workers and public living around the kiln due to the presence of natural radioactivity in the agricultural soils.