以国家标准为基础,对环境水体中90Sr和137Cs的监测方法进行了技术改进:增大采样量(50~100 L),选择高效沉淀剂和低水平探测器.采用改进后的方法测定了50~100 L水中90Sr和137Cs,结果显示:90Sr和137Cs的浓集效率分别为(91.3±2.8)%和(97.2±1.4)%;90Sr的全程回收率为81.5%±2.8%;90Sr和137Cs的探测下限分别为8.6×10-4 Bq/L和9.8×10-4 Bq/L.50 L水中90Sr的比对结果显示,4家实验室测定值与标称值的相对偏差均小于11%.以上结果表明,该方法适用于环境水中微量90Sr和137Cs的监测,可满足环境本底调查和环境监测的要求.
Based on the national standard,the monitoring method of 90Sr and 137Cs in the environmental water was improved,such as increasing the sampling(50-100 L),selecting effective precipitant and low level detector.90Sr and 137Cs in the water(50-100 L) were measured using the improved method.Results show that the concentration efficiency of 90Sr and 137Csare (91.3+2.8)% and (97.2+1.4)%.The full recovery of 90Sr are 81.5%±2.8%.The minimum detectable limit of 90Sr and 137Cs are 8.6 × 10-4 Bq/L and 9.8 × 10-4 Bq/L respectively.The comparison results about 90Sr in the water(50 L) show that the relative deviation of measured value of four units and the nominal value is less than 11%.The results show that this method is applicable to monitoring trace of the radioactive in the environment water and can meet the requirements of environmental background survey and environmental monitoring.