Radioactivity in chemical fertilizers used in Bangladesh

The radioactivity concentrations of Ra-226, Th-228 and K-40 in different chemical Fertilizers, triple superphosphate (TSP), single superphosphate (SSP), diammonium phosphate (DAP), phosphogypsum, muriate of potash (MOP), urea, zinc sulfate and zinc oxysulfate used in the agricultural soil of Bangladesh have been analyzed by gamma spectrometry using a high purity germanium (HPGe) detector: In the fertilizer samples, Ra-236 ranged from 4.8 +/- 0.8 to 323.8 +/- 24.4 Bq kg(-1), Th-228 ranged from 3.4 +/- 1.7 to 22.0 +/- 2.8 Bq kg(-1), and K-40 ranged from 7.9 +/- 2.4 to 12628.5 +/- 169.0 Bq kg(-1). The ratio of radium to thorium was determined, the Ra-226/Th-228 ratio ranged from 0.237 to 18.69. This study could be useful as baseline data for radiation exposure to fertilizers, and their impact on human health. (C) 1997 Elsevier Science Ltd.