Actinides, such as ^238-241Pu, ²⁴¹Am and ⁹⁰Sr have been released into environment through various nuclear activities in the past decades. These α-and β-emitting radionuclides are regarded as highly hazardous pollutants due to their long half-lives, significantly radiological and biological toxicities, as well as long persistence time in the environment. the measurements of and ratios between these radionuclides are of great interest for the environmental risk assessment, radiological protection and source identification.

Currently the most available methods are only suitable for rapid analysis of small-size α-and β-emitting radionuclides sample (<5 g for soil) in response to nuclear emergency. In routine environmental monitoring and tracing studies, a large-size sample (tens of grams) is usually required to achieve adequate detection limits. Therefore, a more robust and sensitive method for a robust method for simultaneous analysis of ultra-trace levels of ^{238,239,240,241}Pu, ²⁴¹Am and ⁹⁰Sr/⁹⁰Y in environmental soils and sediments using successive co-precipitation combined with extraction chromatography and sensitive measurement technology is developed at CIRP.

Since the sample preparation (e.g. ashing, digestion, co-precipitation, etc.) needs to be performed only once, this new method has particular advantages when several actinides and 90Sr/90Y must be simultaneously determined in a limited amount of environmental sample (e.g., soil or sediment core sample). The preparation of 12 samples from the first hydroxide coprecipitation to column separation can be completed in one day, and the processing time for stacked column separation step is usually about one day when vacuum box is used. The purified 90Y was measured immediately and non-destructively by TDCR Cherenkov counting before it decayed away, and the Y recovery was conveniently measured by XRF analysis. The further purification of Am can be carried out in the third day. Due to removal of some time-consuming steps, such as evaporation for the matrix conversion, the total chemical preparation time can be reduced to four days. Meanwhile, the labor cost and the production of chemical wastes were also significantly reduced. The soil samples spiked with certified reference materials and procedural blanks were analyzed to evaluate the performance of this method. For the purpose of environmental monitoring and tracing studies, the developed method will be a promising candidate to simultaneously measure actinides and low levels in large-size solid samples.

Contact: official@cirp.org.cn