A RAPID METHOD FOR DETERMINING SR-90 IN CONTAMINATED SAMPLES OF SOIL AND PLANT

A rapid method for determining Sr-90 has been applied to a large numbe r of soil and plant samples contaminated for experimental purposes or following a nuclear accident. The method provides results in 48 h. A s table strontium carrier marked with Sr-85 is introduced into a sample immediately before its treatment by HNO3, HF and H2O2. The strontium i s extracted from the acid solution by an organic phase composed of cro wn-6 dicyclohexyl-18, then re-extracted with distilled water and count ed using a multi-marked liquid scintillation technique. For a 25 g sam ple, the strontium extraction yield is 70-85%, and the detection limit using a low background counter is 20 Bq kg(-1). The method has been t ested on reference materials.