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

Authors:
  • DED.G. Easterly
    D.G. Easterly
  • BDB.J. Demott
    B.J. Demott
  • RCR.G. Cragle
    R.G. Cragle
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Abstract
Milk from two Jersey cows dosed orally with strontium ~ ~nd calcium ~ was mechanically separated into skimnfilk 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 ~ and Ca ~ in the skimmilk was removed from the second 100 ml. passed through the column ; whereas, in the tenth 100 ml., 50% of each isotope was renmved, using either of the Dowex resins. The Duolite resin was not as effective when used under these conditions. An experiment in which Sr ~ and Ca '~ 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 ~ 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.