Assessment of radioactive pollution around a fertilizer factory complex in the North-Eastern part of Bangladesh

The activity concentrations of soil, water and fertilizer samples 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 activity concentrations of 226Ra ranged from 3.16 ± 0.32 to 10.28 ± 0.55 Bq.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 ± 0.25 to 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 ± 0.05 to 3051.71 ± 19.53 Bq.kg-1 for these samples, respectively. The radium equivalent activity, the hazard indices, the gamma activity concentration index, the indoor absorbed dose rate and the corresponding annual effective dose were estimated for the potential radiological hazard of the collected samples. The calculated values of the representative level index values (Iγr) for all samples of the study area are lower than unity except the MOP sample. The activity ratios were also measured. These values are compared with reported values for other countries of the world. The results of the comparison studies show that the radioactivity concentrations and other radioactive indices of the samples of the study area are below the internationally accepted maximum permissible values. Therefore, this region is safe from any radiation hazard and no significant radiological threat was observed to the population of the study area. (authors)