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

Abstract

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.