Transfer coefficients of radionuclides secreted in milk of dairy cows.

This study simulated experimentally the transfer of radionuclides to milk of dairy cows on a worst-case situation using various radionuclides known to emanate from nuclear power stations and which have been detected on particulates. Two lactating Holstein cows were administered orally one gelatin capsule containing 10 radionuclides in water-soluble form per day for 14 consecutive days. Milk samples were collected and aliquots analyzed in a germanium lithium-drifted detector coupled to a 2048-multichannel gamma-ray analyzer to measure small amounts of complex mixtures of radionuclides. The transfer coefficients of the radionuclides were calculated when their secretion in milk reached or approached a plateau of concentration. The radionuclides and their transfer coefficients to milk were: chromium51 less than .01%; manganese54 .033 +/- .005%; cobalt60 .01 +/- .002%; iron59 .0048 +/- .002%; zinc65 .31 +/- .07%; selenium75 .29 +/- .1%; antimony125 .011 +/- .003%; iodine131 .88 +/- .05%; and cesium137 .79 +/- .08%.