Radionuclides determination by alpha (210Po, 228,230,232Th) and gamma (226,228Ra, 137Cs, 40K) spectrometry in children's food in Croatia with assessment of cumulative ingestion dose for infants

This work presents comprehensive results of alpha (Po-210, Th-228,Th-230,Th-232) and gamma (K-40, Ra-226,Ra-228, Cs-137) radioactivity measurements in selected food typically consumed by infants (< 1 year) in Croatia. The samples of readily available infant's food on Croatian market were categorized according to the growth of an infant, from their first nourishment: adapted powdered milk, to their first solid food. The aim was to estimate ingestion doses and the potential radiological risks for infants. In addition to anthropogenic radionuclides, the study focused on naturally occurring radionuclides often underrepresented in similar researches. K-40 prevails in activity concentrations in all types of samples. Po-210 was determined in all sample types reaching up to 502 mBq/kg. Maximum values of activity concentrations for Ra-228, Ra-226 and Th isotopes were 230 mBq/kg, 1.29 Bq/kg and 52 mBq/kg, respectively. The most important contributors to the annual effective dose were K-40, Ra-226, Po-210 and Ra-228 contributing with 29 % 28 %, 24 % and 17 %, respectively. Th isotopes contributed with less than 2 %, while the contribution of anthropogenic radionuclides Cs-137 and Sr-90 were negligible (less than 1 %). Cumulative effective ingestion dose for infants was calculated to be 0.69 mSv/y, which is below the recommended limiting dose of 1 mSv/y. Largest proportion comes from the intake of fruit (33 %), followed by the intake of vegetables 19 %) and cereals 19 %). Although national radioactivity monitoring programs usually focus on anthropogenic radionuclides, this study highlights that naturally occurring radionuclides are dominant contributors to the cumulative effective ingestion dose in infants. Overall, the estimated cumulative effective ingestion dose for infants from consuming food available in Croatia is below recommended dose limits and therefore does not present a radiological concern.