Radiostrontium In Milk Research Articles

Role of the IAEA's ALMERA network in harmonization of analytical procedures applicable worldwide for radiological emergencies

The International Atomic Energy Agency (IAEA) coordinates and provides analytical support to the worldwide network of Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA). The goal of ALMERA is to provide timely and reliable measurement results of environmental radioactivity in routine monitoring and emergency situations. Finding and choosing the most adequate analytical procedures for environmental monitoring can be a challenge for laboratories due to a wide variety of technologies available and the rapid developments in this field. To respond to this challenge, the IAEA has included within its ALMERA activities, the development and validation of a set of procedures for the determination of natural and anthropogenic radionuclides in environmental samples, for both routine and emergency environmental monitoring. Methodological harmonization, in turn, leads to enhanced worldwide comparability of environmental radioactivity measurement results. The respective analytical procedures are developed by expert groups from ALMERA member laboratories and validated through several ALMERA laboratories worldwide according to a comprehensive methodology. In addition to sequential analytical procedures for routine environmental monitoring, rapid procedures applicable for radiological emergencies have been developed and validated for the determination of americium and plutonium radioisotopes in soil and sediment samples, radiostrontium in milk, and radium isotopes in drinking water. Currently, the development of rapid procedures for radiostrontium analysis in soil and seawater is underway, partly prompted by the interest for high throughput procedures following the analytical burden of laboratories after the Fukushima Daiichi NPP accident.

Determination of radiostrontium in milk samples by ultra-low-level liquid scintillation counting: a validated approach

Strontium-90 is a hazardous radionuclide derived from nuclear fission processes, and it decays emitting high-energy beta-particles forming yttrium-90. It may be easily absorbed in humans through several food supply chains, since it is chemically similar to some important biological elements such as potassium and calcium. In this work an analytical method for the determination of radiostrontium in milk by liquid scintillation counting was developed in order to obtain a precise quantification at low activity concentration levels. Moreover, a full validative approach was applied to confirm method reliability. Good analytical performance was obtained by developing an in-house validation model according to Regulation 882/2004/EC and Decision 657/2002/EC with a good selectivity, a decision threshold and detection limit corresponding to 0.003 and 0.006 Bq l–1 (α = β = 0.05) respectively, a repeatability value, expressed as CV%, equal to 13%, a mean recovery value equal to 102.5% and a measurement uncertainty equal to 11.5%. Strontium and yttrium chemical yields were determined by a reliable analytical method by inductively coupled mass spectrometry, assuring a suitable correction of final result. The results of the method validation, combined with a quality control assurance, performed on a reference material, demonstrated that the procedure represents a substantial improvement in the determination of 90Sr relating to accurate confirmation analyses.

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

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.

Fast method and ultra fast screening for determination of 90Sr in milk and dairy products

In emergency situation or in case of defence against nuclear hazards, the rapid analysis of radioisotopes in food products is essential. Radiostrontium is one of the most interesting isotopes in case of emergency. The determination of radiostrontium in milk and dairy products plays an important role especially for infants. The procedures described here were tested for fast determination of 90Sr. The typical chemical recovery of the proposed fast procedure for determination of strontium from milk and dairy products was 90% and the time needed for analysis was one working day. The achieved detection limit for milk is 0.8 Bq/l. An ultra fast screening method allows the determination of radiostrontium with quantitative recovery within 1 hour. The minimum detectable activity in this case is 230 Bq/l.

Validation of rapid methods for the determination of radiostrontium in milk

A rapid method of 89Sr and 90Sr comprising ion chromatography for preconcentration and Sr extraction chromatography for separation of Sr from Ca, Ba and Y was validated with spiked milk samples. An 89Sr/ 90Sr activity ratio of up to 12 showed the relative bias was within ±20%. The separation time of Sr was 7 h and the chemical recovery of Sr ranged from 80% to 95%. The detection limit for 500 mL milk and 90 min counting time was 0.1 Bq L −1.

Methodology for determination of radiostrontium in milk: a review

This paper presents a review on all available analytical methods for 90Sr and 89Sr determination in milk. Special attention was focused on the parameter of the performing time in order to assess the rapid measurement of milk contamination, especially in the case of emergency situations such as a nuclear plant accident. Preliminarily, a short description of the milk matrix and radiostrontium transfer from soil to milk and its derivatives is given. Then analytical procedures are examined step by step. 90Sr and 89Sr can be separately determined in less than 2 days by a rapid

Rapid method for the determination of radiostrontium in milk

A radiochemical procedure comprising ion chromatography for preconcentration, oxalate precipitation for alkali/alkaline earth separation, strontium specific extraction chromatography with a crown ether for calcium/strontium separation, carbonate precipitation for counting on a low background proportional counter, provides a simple, rapid (48 h) and effective method for radiostrontium determination in emergency situation in milk. The separation scheme gives a strontium recovery rate of 62% and an empiric relative standard deviation of 11%. The detection limit for 500 ml milk and 3600-second counting time is 0.090 Bq.l-1.

Rapid trace determination of radiostrontium in milk and drinking water

A rapid method for determining traces of radiostrontium in milk and drinking water is described. The technique involves a batch treatment of the milk sample with a cation exchanger (DOWEX 50W X8) followed by a solvent extraction with a crown ether (DC18C6) and a precipitation of SrCO3. In the case of water, the strontium is extracted directly with the crown ether. The average separation yield is 74% for milk and 91% for water. The overall separation procedure takes about 8 hours. Activities as low as 0.03 Bq/1 can be determined with a low background GM-counter.

TRANSFER OF RADIO STRONTIUM FROM MILK TO CHEESE AND WHEY.

ALTHOUGH much information is available on the amount of radio strontium in milk, only a few results have been published on the transfer of these isotopes to products manufactured from radioactive milk. The ratio of radio strontium to calcium in cheese is often assumed to be similar to that in the milk from which it is produced1. From experiments with strontium-89 and calcium-45 dosed to the milk, Demott and Craggle2 concluded that Cheddar cheese made from this milk showed a slightly larger ratio of 89Sr/45Ca than did the original milk. The ratio (89Sr/45Ca in cheese)/(89Sr/45Ca in milk) appeared to be 1.23 ± 0.28. If, however, the cheese was made from milk of cows to which oral doses of these isotopes were given, this ratio was found to be 1.06 ± 0.12. The latter value agrees reasonably with that found by Lengemann3 for Cheddar cheese from milk of cows to which strontium-85 was dosed orally. In whey the 89Sr/45Ca ratio compared with that in milk was 0.85 ± 0.10 and 0.62 ± 0.07 for dosed milk and dosed cows respectively2. From these results it might be concluded that the way in which the strontium-tracer is introduced into the milk influences the transfer of the isotope from milk to cheese. So for the study of the movement of fission products through the food-chain to man, it is better to measure the fall-out strontium-activity in milk and its products.

The determination of radiostrontium in milk and herbage

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Separation of Calcium and Strontium by Liquid Ion Exchange. Determination of Total Radiostrontium in Milk.

A rapid liquid ion exchange method is described for separating quantities of calcium from strontium in dilute acid solution. Separate extractions were made with di-2ethylhexyl phosphoric acid (HDEHP) dissolved in toluene after stepwise pH adjustments of the aqueous solution. Calcium, strontium, and other cations in 250 ml of milk were first concentrated in 60 ml of dilute HCl solution by a batch ion exchange resin technique. After separation of calcium and radiostrontium by the liquid ion exchange method, Sr/sup 89/ and Sr/sup 90/ were stripped from the final organic phase with 3N HNV/sub 3/ and precipitated from fuming nitric acid. The counting planchet contained only 2% of the calcium and 85 plus or minus 51% of the strontium in the original milk sample. Decontamination factors for Y/sup 90/, Cs/sup 137/, K/sup 40/, La/sup 14 and I/sup 131/ were greater than 10/sup 3/. Ballo, if present, can be removed by homogeneous precipitation of barium chromate. (auth)

Secretion of Radio-Strontium in Milk of Two Cows Following Intravenous Administration.

Summary7.88% and 11% of a dose of radio-strontium were secreted in the milk of two Holstein cows during 4 1/4 days following its intravenous administration.