A rapid method for determining strontium-90 in contaminated samples of soil and plant

A rapid method for determining 90Sr has been applied to a large number of soil and plant samples contaminated for experimental purposes or following a nuclear accident. The method provides results in 48 h. A stable strontium carrier marked with 85Sr is introduced into a sample immediately before its treatment by HNO3, HF and H2O2. The strontium is extracted from the acid solution by an organic phase composed of crown-6 dicyclohexyl-18, then re-extracted with distilled water and counted using a multi-marked liquid scintillation technique. For a 25 g sample, 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 tested on reference materials.