Strontium-90 In Milk Research Articles

Radiation and hygienic situation in Tatarstan Republik

Caesium-137 of a global origin is found in some regions of Kazan, near the Volga and near the Kama. The greatest density of distribution does not exceed the level of 18,5 kBq/m2. The collective dose of irradiation from global precipitation equals 48 persons/Sv. The content of caesium-137, strontium-90 in milk, meat, potatoes and bread is about 1000 times smaller than the prescribed allowable levels for the present. Technogenic contamination by radium-226 is found in some areas of industrial territories in Kazan, Mendeleevsk, Chistopol, Almetyevsk and Naberezhnye Chelny. Medical radiologic investigations have a pronounced effect on the collective dose of irradiation.

Membraneless dialysis of strontium in aqueous liquid-liquid milk-pectin system

Binding of added strontium by milk proteins under native conditions was investigated using pectin of various degrees of esterification. The partition of strontium, as well as cesium and europium, in aqueous two-phase milk-pectin system, is discussed in terms of “membraneless dialysis” and described by Donnan equilibria, and compared with the distribution between cation exchanger and milk, artificial milk serum, or pectin solutions. When going from pectin with a degree of esterification D.E.=93.2 to 61.4, the distribution of strontium decreases for about 40% in favor of pectin phase and this was explained by a relatively lower degree of dissociation of free carboxyle groups of pectin. The low-molecular fraction of added strontium in milk was assessed from Dowex 50×8 sorption data to be 31%, and that of cesium and europium 58% and 40%, respectively. However, distribution ratio of strontium and europium in milk/pectin system is much higher than it would correspond to the ion exchanger adsorption data.

Solvent extraction separation of strontium as 18-crown-6 complex with picrate ion

Strontium (5-250 ..mu..g mL/sup -1/) was quantitatively extracted with 0.01 M 18-crown 6 at pH 3.0-9.0 from a solution containing 0.1 M picric acid in the presence of 2 mL of ethyl alcohol. Strontium from the organic phase was stripped with 1 M nitric acid and determined flame photometrically at 460 nm. A study of nature of extracted species revealed the composition of metal to crown ether to picrate ion as 1:1:2. Chloroform was the most suitable diluent. Most mineral acids were good stripping agents. Strontium was separated from S-block elements lead, uranium, and thorium in binary mixtures. It can also be separated from alkali, alkaline earths, and common anions in tertiary mixtures. The method was extended for analysis of strontium in milk and geological samples.

Ion Exchange Determination of Strontium-89 and Strontium-90 in Milk: Collaborative Study

Abstract Eleven collaborators performed a second collaborative study of an ion exchange method for determining strontium-89 and -90. For milk containing 29.0 and 197 pCi/L of strontium- 89, the results at 2 levels were: average 31.0, 199.6; range 26-36, 164-290; standard deviation 2.9, 7.2; and per cent error 10.0, 3.4. For milk containing 32.4 and 151.2 pCi/L of strontium-90, the results were: average 32.5, 149.9; range 27.2-38.0, 125.3-170.3, standard deviation 0.32, 4.17; and per cent error 0.9, 2.8. The method has been adopted as official first action.

Ion Exchange Determination of Strontium-89 and Strontium-90 in Milk: Collaborative Study

Abstract A method for the determination of strontium-89 and strontium-90 in milk, involving ion exchange and purification with nitric acid, was evaluated by 11 collaborators. The accuracy of the method for strontium-89 ranged from 2 to 56% and the within-laboratory precision ranged from 11 to 76% for a concentration range of 68–480 pCi/L; values for strontium-90 in a concentration range of 50.2–116.2 pCi/L were 6.4 to 10 and 4 to 11%, respectively. The slight bias on the high side for strontium-90 was not considered serious. The collaborators had difficulty with strontium-89 analyses, as shown by the high precision and accuracy estimation values.

Copper, Iron, Manganese, Strontium, and Zinc Content of Market Milk

Samples of market milk collected in alternate months from February 1967 to February 1968 from cities in the United States were analyzed for copper, iron, manganese, strontium, and zinc by atomic absorption spectrophotometry. Ranges and national averages for trace elements in milk, expressed as milligrams per liter, varied as follows: Cu, .044 to .190 and .086; Fe, .20 to 1.51 and .64; Mn, .033 to .211 and .091; Sr, .040 to .480 and .171; and Zn, 2.30 to 5.10 and 3.28. Statistically, the data showed significant differences among months and locations. Trace element contents in milk from the east were significantly different from those in the west; however, means or per cent differences between areas (except for Sr) were less than 10%. Strontium in milk from the west was higher than that from the east. Strontium means were greater than .200mg per liter in Arizona, California, Colorado, Kansas, Nevada, New Mexico, South Dakota, Utah, and Wyoming. Monthly means for all trace elements showed that Zn was constant throughout the year, whereas other elements were lowest in summer and highest in winter.

Levels of stable strontium in milk and the total diet

Levels of stable strontium in milk and the total diet

Enrichment and determination of traces of strontium in milk and other calcareous media.

Enrichment and determination of traces of strontium in milk and other calcareous media.

Transfer of Radiostrontium from Cows’ Feed to Milk

Stable strontium, strontium89, strontium90, and calcium intake and excretion into cows’ milk were measured in three herds. The transfer of radiostrontium from feed to milk was observed in strontium89 and strontium90 originating in fallout from nuclear tests and deposited naturally in the grasses and grains of the cows’ feed. One of the herds was continuously on pasture, one was in dry lot and fed stored feed, and one was transferred from dry lot to pasture, maintained on pasture for 19 days, then returned to dry lot. The stored feed was low and the pasture grass high in radiostrontium content. Change from the high- to the low-radiostrontium diet decreased radiostrontium concentration in milk with combined half-times of 0.77 and 4.6 days. The observed ratio from feed to milk for stable strontium to calcium was 0.12. For radiostrontium, a higher observed ratio occurred with a low-radiostrontium diet and a lower one with a high-radiostrontium diet. This was due to a change in specific activity between feed and milk and was attributed to the appearance in milk of strontium from the cow's body pool. Of the stable strontium in milk, approximately 40% was estimated to derive from the skeleton.

THE EVALUATION OF A RAPID SOLVENT EXTRACTION METHOD FOR THE DETERMINATION OF STRONTIUM-90 IN MILK.

THE EVALUATION OF A RAPID SOLVENT EXTRACTION METHOD FOR THE DETERMINATION OF STRONTIUM-90 IN MILK.

AN ION-EXCHANGE METHOD FOR THE ESTIMATION OF STRONTIUM-90 IN MILK.

THE classical method of Bryant et al.1 for the estimation of strontium-90 in milk is both tedious and hazardous. Davis2, Farabee3 and other workers4,5 have all reported separations of strontium from calcium using ion-exchange methods, and such techniques would appear to offer promise for the estimation of strontium-90 in milk.

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.

Improved Determination of Strontium-90 in Milk by an Ion Exchange Method.

An improved procedure is described for the determination of Sr/sup 90/ in milk by ion exchange. The procedure consists of storing the milk samples with formaldehyde preservative for the ingrowth of the Y/sup 90/ daughter of Sr/sup 90/ , adding Y carrier, and then passing the milk consecutively through cation and anion exchange resin columns. The alkaline earth ions in milk are replaced by sodium ions in the cation exchange column, after which the Y is retained as an anionic complex, sodium citrate, in the anion exchange column. The effluent milk is discarded and the Y complex on the anion exchange resin is destroyed with HCl. The Y, eluted with the acid, is precipitated as the oxalate, and the radiortrium is measured with a lowbackground beta counter. (P.C.H.)

Strontium-90 in man. V.

1) It is now possible to predict the strontium-90 concentration in the world population for specified modes of atmospheric contamination with moderate reliability. For example, the average adult bone level in the eastern United States 5 years after the detonation of a specified quantity of fission products into the lower polar stratosphere can probably be estimated to better than +/- 50 percent. 2) The concentration of strontium-90 in fetuses reached a maximum of 1.2 micromicrocuries of strontium-90 per gram of calcium in eastern North America and began to decrease significantly in 1960 and 1961. The ratio of the strontium-90 level in the fetus to the level in the average diet of the adult is about 0.08. 3) The average rate of turnover of strontium and calcium in the adult skeleton appears to be about 2.5 percent per year, although there is considerable difference among the various bones of the body. 4) The standard deviation for strontium-90 concentration in a population of urban adults appears to be about 40 percent of the mean. The distribution curve for an interval of from 60 to 0.1 percent of the population may be approximated by the log-normal function. In urban populations of Western culture the concentration for 5 percent of the population will exceed twice the mean, that for 0.1 percent will exceed four times the mean. 5) Cities in the Southern Hemisphere showed levels in bone about half those for cities of Western culture in the Northern Hemisphere in 1960, yet the fallout in the Southern Hemisphere is only one-fourth that in the Northern Hemisphere. This is attributed to differences in diet, with a higher milk component in the Northern Hemisphere. 6) A simple model for the strontium-90 concentration in the bones of young people as a function of their age appears to fit the experimental data. 7) The coefficients of the equation describing the relative contributions of the rate of fallout (direct absorption) and the cumulative deposit (soil up-take) to the strontium-90 concentration in milk have been calculated from the observed data for 1959 and 1960. They are as follows: rate factor A = 0.65 micromicrocurie of strontium-90 per gram of calcium in milk per millicurie of strontium-90 per square mile during the growing season; cumulative-deposit factor B = 0.12 micromicrocurie of strontium-90 per gram of calcium in milk per millicurie of strontium-90 per square mile at the midpoint of the growing season. The predicted levels in milk for 1958 obtained with these coefficients are in excellent agreement with the observed levels. In 1958 and 1959 about half the strontium-90 in milk was attributable to the rate factor, whereas in 1960 the contribution of the rate factor dropped to about 15 percent. 8) Future levels of strontium-90 in man are given (i) for the next decade as a result of the nuclear tests through 1961 and (ii) under the assumption that 1.0 megacurie of strontium-90 is added to the stratosphere of the Northern Hemisphere each year. 9) The radiation doses to the skeleton to be expected from world-wide fallout on the basis of a 3000-megaton (fission yield) war are also given.

Availability to man of strontium in cow's milk.

SummaryA double tracer method has been used to measure the availability-of strontium in cow's milk. Thus, strontium-87m as a dilute aqueous solution of strontium chloride was added to milk from a cow which had Received strontium-85 intravenously. Urines were collected from 6 adult volunteers after ingestion of this milk mixture. It is shown that the availability of strontium in the milk is equal to that of strontium as chloride in dilute aqueous solution. The consequences of the result upon the specific activity of strontium-90 from fallout in certain body pools are discussed.

Determination of Strontium-90 in Milk by an Ion Exchange Method

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of Strontium-90 in Milk by an Ion Exchange MethodCharles. Porter, Daniel. Cahill, Roger. Schneider, Phillip. Robbins, Wilford. Perry, and Bernd. KahnCite this: Anal. Chem. 1961, 33, 10, 1306–1308Publication Date (Print):September 1, 1961Publication History Published online1 May 2002Published inissue 1 September 1961https://doi.org/10.1021/ac60178a005RIGHTS & PERMISSIONSArticle Views98Altmetric-Citations20LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (393 KB) Get e-Alerts Get e-Alerts

Strontium-90 in Milk, 1960

Strontium-90 in Milk, 1960

Strontium in Milk. III. Distribution in Cream, Skimmilk, Cheddar Cheese, and Whey

Summary Cream of approximately 40% fat from milk containing Sr 89 and Ca 45 has been found to have concentrations of these nuclides equal to about one-half those found in the milk. The skimmilk has slightly higher concentrations than the milk. No difference is apparent in the Sr 89 /Ca 45 ratio between the skimmilk and cream after the first milking following dosing of the cow. Cream containing Sr 89 was washed by reseparation, resulting in a product essentially free of the nuclide. Cheddar Cheese made from milk containing Sr 89 and Ca 45 showed a slightly larger ratio of Sr 89 /Ca 45 than did the milk from which it was made. Fourteen vats of cheese made from dosed milk had a S r 89 / C a 45 cheese S r 89 / C a 45 milk ratio of 1.23±0.28. Four vats of cheese made from milk of dosed cows showed a ratio of 1.06±0.12. The Sr 89 /Ca 45 ratio in whey was less than in the milk.

Strontium in Milk. II. Removal by Batch Ion Exchange Methods

Summary Skimmilk containing Sr 89 and Ca 45 was left in contact with Dowex 50W-X12 in the calcium form for periods of 1, 10, 60, and 120min. Apparent equilibrium was reached between the 1- and 10-min. periods. A dosed milk-resin ratio study showed that as the ratio increased, the percentage of removal of Sr 89 and Ca 45 decreased. The percentage removal ranged from a high of 94 and 93 for Sr 89 and Ca 45 , respectively, at a milk-resin ratio of 2, to a low of 21% Sr 89 and 16% Ca 45 at a milk-resin ratio of 200. At a milk-resin ratio of 2, 4.27% of the resin capacity was utilized and at a ratio of 200, 73.6% was utilized for exchange of Sr and Ca.

Strontium in Milk. I. Removal by Means of Reverse-Flow Ion Exchange Columns

Summary Milk from two Jersey cows dosed orally with strontium 89 and calcium 45 was mechanically separated into skimmilk and cream. These radioactive isotopes were removed from the skimmilk by use of an upward-flow ion exchange resin column. Dowex 50W-X12, Dowex 50W-X4, and Duolite C-20 were used. The calcium form of ecah resin was more effective in removal of the isotopes than was the sodium form. Between 70 and 80% of the Sr 89 and Ca 45 in the skimmilk was removed from the second 100ml. passed through the column; whereas, in the tenth 100ml., 50% of each isotope was removed, using either of the Dowex resins. The Duolite resin was not as effective when used under these conditions. An experiment in which Sr 89 and Ca 45 were put directly into skimmilk and allowed to stand for 16 hr. resulted in removals which followed very closely those of the experiment with skimmilk from dosed cows. However, a higher percentage of Sr 89 was removed than from the skimmilk of dosed cows. Treated milk contained more calcium, had a lower pH, greater titratable acidity, and shorter rennet coagulation time than untreated milk. Resin preference of strontium over calcium was shown.