The presence of primordial radionuclides in powdered milk and estimation of the concomitant ingestion dose

Milk and milk-based foodstuffs are considered as a primary source of nutrition to human health. Therefore, monitoring of hazardous material in powdered milk is important for the safety of public health. This study determines the concentrations of primordial radionuclides in powdered milk samples collected from the local markets of Dhaka city in Bangladesh using HPGe gamma-ray spectrometry. The mean activity concentrations of Ra-226, Th-232 and K-40 for infant (9.6 +/- 2.10, 9.0 +/- 1.5 and 164.5 +/- 3.7 Bq kg(-1), respectively) were found comparable to the people of all other ages (7.2 +/- 3.7, 7.4 +/- 1.5 and 143.2 +/- 3.9 Bq kg(-1), respectively). Based on the typical consumption characteristics of powdered milk, the mean annual effective doses were found below the FAO/WHO (1995) and ICRP (2007) recommended limit of 1 mSv y(-1) for public exposure, in all investigated age groups (2 y - 17 y). On the other hand, the doses for infant show close to the UNSCEAR (2000) reference ingestion dose constraints of 290 mu Sv y(-1), which may indicate a non-negligible concern for the infants' health. The carcinogenic risks due to the ingestion of radionuclide show to be 6.4 x 10(-4) (0-72 years) and 5.4 x 10(-4) (>2 years) are significantly less than the ICRP (2006) suggested cancer risk factor of 2.5 x 10(-3) based on the annual dose limit of 1 mSv for general public, thus discarded the radiation hazards via the consumption of local or imported powdered milk in Bangladesh. Overall, the measured data may help to establish national rules and regulations on powdered milk relating to radiological protection for the general people of Bangladesh.