本文件描述了测量土壤样品中90Sr与90Y和89Sr（纯β放射性核素）平衡活度的原理。介绍了不同的化学分离方法来产生锶源和钇源，其活性由比例计数器（PC）或液体闪烁计数器（LSC）测定。当达到90Sr和90Y之间的平衡或通过直接测量90Y时，可从试样中获得90Sr。测量方法的选择取决于污染物的来源、待分析土壤的特性、所需的测量精度和可用实验室的资源。 这些方法用于过去或现在、意外或常规、液体或气体排放后的土壤监测。它还包括监测全球核沉降物造成的污染。 在核事故后不久发生的放射性沉降物中，89Sr对锶放射性总量的贡献不容忽视。本标准提供了测定89Sr存在时90Sr活性的测量方法。 本文件中所述的试验方法也可用于按照适当的取样程序测量污泥、沉积物、建筑材料和产品中的放射性核素。 使用20 g的样品尺寸和1000 min的计数时间，当可以忽略89Sr的存在时，使用常规和商用比例计数器或液体闪烁计数器，90Sr的检测限可达到（0,1至0,5）Bq·kg-1。如果测试样品中存在89Sr，则使用与前一种情况相同的样品大小、计数时间和比例计数器或液体闪烁计数器，90Sr和89Sr的检测限均为（1至2）Bq·kg-1。

This document describes the principles for the measurement of the activity of 90Sr in equilibrium with 90Y and 89Sr, pure beta emitting radionuclides, in soil samples. Different chemical separation methods are presented to produce strontium and yttrium sources, the activity of which is determined using proportional counters (PC) or liquid scintillation counters (LSC). 90Sr can be obtained from the test samples when the equilibrium between 90Sr and 90Y is reached or through direct 90Y measurement. The selection of the measuring method depends on the origin of the contamination, the characteristics of the soil to be analysed, the required accuracy of measurement and the resources of the available laboratories. These methods are used for soil monitoring following discharges, whether past or present, accidental or routine, liquid or gaseous. It also covers the monitoring of contamination caused by global nuclear fallout. In case of recent fallout immediately following a nuclear accident, the contribution of 89Sr to the total amount of strontium activity will not be negligible. This standard provides the measurement method to determine the activity of 90Sr in presence of 89Sr. The test methods described in this document can also be used to measure the radionuclides in sludge, sediment, construction material and products by following proper sampling procedure. Using samples sizes of 20 g and counting times of 1 000 min, detection limits of (0,1 to 0,5) Bq·kg-1 can be achievable for 90Sr using conventional and commercially available proportional counter or liquid scintillation counter when the presence of 89Sr can be neglected. If 89Sr is present in the test sample, detection limits of (1 to 2) Bq·kg-1 can be obtained for both 90Sr and 89Sr using the same sample size, counting time and proportional counter or liquid scintillation counter as in the previous situation.