A Method for the Determination of Radionuclides in Milk Ash

Abstract

Summary A modified method suitable for routine monitoring for the determination of four radionuclides (total radiostrontium, strontium 90 (yttrium 90 ), barium 140 , and cesium 137 ) in the ash from one liter of milk, is described. With this method, based on radiometric analyses and employing β - or γ -counting as applicable, recoveries are as follows: strontium, 82±2%; yttrium 90 (strontium 90 ), 77%±4%; barium 140 , 85%±4%; and cesium 137 , 96%±3%. The over-all recovery of strontium 90 (yttrium 90 ), taking into account the recovery of strontium, is 64%±5%. These values indicate sufficient precision for most purposes. The major reason for loss of strontium and barium activity in the nitric acid treatment step is the low acid concentration (64–65%) employed. The interference of strontium on barium and barium on strontium is less than 1%, whereas the presence of cesium has no effect on the determination of strontium and barium activity. The results obtained on milk samples using this method are presented elsewhere (6).