Survey on the presence of⁹⁰Sr in milk samples by a validated ultra low level liquid scintillation counting (LSC) method

Abstract

Abstract.90 Sr is one of the most biologically hazardous radionuclides produced in nuclear fission processes and decays emitting high-energy beta particles turning 90 Y. 90 Sr is transferred from soil-plant to cow's milk and then to humans if it is introduced into the environment. Radiostrontium is chemically similar to calcium entering the human body through several food chains and depositing in bone and blood-forming tissue (bone marrow). Among main foodstuffs assumed in human diet, milk is considered of special interest for radiostrontium determination, especially in emergency situations, because the consumption of contaminated milk is the main source of internal radiation exposure, particularly for infants. In this work an analytical method for the determination of radiostrontium in milk was developed and validated in order to determine low activity levels by liquid scintillation counting (LSC) after achieving 90 Y secular equilibrium condition. The analytical procedure was applied both in surveillance and routine programmes to detect radiocontamination in cow's, goat and sheep milk samples.

Beta emitter radionuclides (90Sr) contamination in animal feed: validation and application of a radiochemical method by ultra low level liquid scintillation counting

“…Caratteristica molto importante dal punto di vista analitico è la capacità di 90 Sr e 90 Y di raggiungere il cosiddetto equilibrio secolare ovvero lo stato in cui le concentrazioni di attività dei due isotopi sono equivalenti. Essendo l’energia massima di emissione dell’ 90 Y circa 5 volte maggiore rispetto a quella dello 90 Sr, risulta favorevole la sua determinazione, in luogo di quella del radioisotopo progenitore, con evidente guadagno in sensibilità analitica (dell’Oro et al ., 2013 ).…”

Fast and Sensitive Radiochemical Method for Sr-90 Determination in Food and Feed by Chromatographic Extraction and Liquid Scintillation Counting

“…After approximately 2 weeks, Y-90 is in secular equilibrium with its parent nuclide; this property is exploited for the indirect determination of Sr-90 activity (dell'Oro et al 2013). Therefore, the determination of Sr-90 can be performed in two ways: direct or indirect.…”