The activity concentrations of soil, water and fertilizersamples were determined by using high-resolution gamma spectrometry(HPGe detector: 40% relative efficiency) with a PC-based MCA system.The samples were collected from the area of a urea fertilizer factory,lagoon and Shitalakhya river in Narsingdi, Bangladesh. The activityconcentrations of 226Ra ranged from 3.16 ± 0.32 to 10.28 ± 0.55Bq.kg-1, 1.22 ± 0.41 to 7.36 ± 0.42 Bq.L-1 and 3.55 ± 0.33 to 90.65± 3.17 Bq.kg-1 for soil, water and fertilizer samples, respectively.The 232Th activity concentrations ranged from 4.89 ± 0.45 to 15.82± 0.45 Bq.kg-1, 1.21 ± 0.06 to 8.59 ± 0.37 Bq. L-1 and 4.76 ± 0.25to 26.38 ± 1.40 Bq.kg-1 for soil, water and fertilizer samples, respectively.The 40K activity concentrations ranged from 24.96 ± 0.23 to 60.49± 0.56 Bq.kg-1, 7.48 ± 0.53 to 35.48 ± 0.24 Bq.L-1 and 3.55 ± 0.05to 3051.71 ± 19.53 Bq.kg-1 for these samples, respectively. Theradium equivalent activity, the hazard indices, the gamma activityconcentration index, the indoor absorbed dose rate and the correspondingannual effective dose were estimated for the potential radiological hazardof the collected samples. The calculated values of the representativelevel index values (Igr) for all samples of the study area are lowerthan unity except the MOP sample. The activity ratios were alsomeasured. These values are compared with reported values for othercountries of the world. The results of the comparison studies showthat the radioactivity concentrations and other radioactive indicesof the samples of the study area are below the internationally acceptedmaximum permissible values. Therefore, this region is safe fromany radiation hazard and no significant radiological threat was observedto the population of the study area.

The natural γ-radiation in samples of a variety of marblesimported into Bangladesh for use in building construction was measured,employing γ-ray spectrometry with a HPGe detector. From the measuredγ-ray spectra, activity concentrations were determined for 226Ra(29.31 ± 2.06 to 46.99 ± 2.97 Bq.kg–1), 232Th (42.91± 2.53 to 62.92 ± 3.37 Bq.kg–1) and 40K (824.42± 15.42 to 1071.58 ± 20.14 Bq.kg–1). The measured activityconcentrations for these natural radionuclides were compared withthe reported data of other countries and with the world averageactivity of soil. The radium equivalent activity (Raeq),the hazard indices, the gamma activity concentration index, theindoor absorbed dose rate and the corresponding annual effectivedose were estimated for the potential radiological hazard of themarble. The Raeq values of all marble samples are lowerthan the limit of 370 Bq.kg–1, equivalent to a dose of1.5 mSv.y–1. The average values of the external and internalhazard indices are less than unity. The average indoor absorbeddose rate (121.25 nGy.h–1) is higher than the population-weightedaverage of 84 nGy.h–1, whereas the corresponding annualdose limit falls within an average value of 0.60 mSv, which is anorder of magnitude below the limit specified for building materialsin the literature. The present results indicate that using marblein building construction in Bangladesh does not pose any significant radiologicalhazard.