本文件描述了测量土壤样品中90Sr与90Y和89Sr（纯β发射放射性核素）平衡时的活度的原理。提出了不同的化学分离方法来生产锶和钇源，使用比例计数器（PC）或液体闪烁计数器（LSC）测定其活性。当90Sr和90Y之间达到平衡时，或通过直接90Y测量，可以从测试样品中获得90Sr。测量方法的选择取决于污染的来源、待分析土壤的特性、所需的测量精度和可用实验室的资源。 这些方法用于监测排放后的土壤，无论是过去的还是现在的、意外的还是常规的、液体的还是气体的。它还包括监测全球核沉降物造成的污染。 在核事故后立即发生沉降的情况下，89Sr对锶活性总量的贡献将不可忽略。本标准提供了在89Sr存在下测定90Sr活性的测量方法。 通过遵循适当的取样程序，本文件中描述的测试方法也可用于测量污泥、沉积物、建筑材料和产品中的放射性核素。 使用20 g的样品大小和1 000 min的计数时间，当89Sr的存在可以忽略时，使用常规和市售的比例计数器或液体闪烁计数器可以实现90Sr的（0.1至0.5）Bq·kg-1的检测限。如果测试样品中存在89Sr，检测限为（1至2）Bq·kg-使用与先前情况相同的样本量、计数时间和比例计数器或液体闪烁计数器，90Sr和89Sr都可以获得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.