摘要目的:建立高灵敏度的海水中 137Cs快速测量方法，并利用该方法开展我国沿海8个省份近岸海水中 137Cs测量的初步应用。 方法:用亚铁氰化镍钾聚丙烯腈(KNiFC-PAN)离子交换树脂材料，通过蠕动泵以60 ml/min过滤吸附海水中的 137Cs。采用海水中加稳定铯的方法，应用电感耦合等离子体质谱仪(ICP-MS)方法测量海水吸附前后铯离子浓度获得吸附效率。制备3个KNiFC-PAN基质成分的 137Cs标准样品对井型高纯锗γ谱仪进行效率刻度，获得其探测效率。以此建立海水中 137Cs的快速测量方法，并将该方法应用于我国沿海海水中 137Cs的测量。 结果:建立的测量方法可在6～8 h内完成20 L海水中 137Cs的过滤吸附，与GB/T 16145－2022标准中用磷钼酸铵-二氧化锰共沉淀方法分离海水中 137Cs所需时间至少要12 h相比，本研究方法在预处理海水的效率上可提升1倍，且铯回收率高达98.02%。制备的3个标准样品效率刻度值的相对标准偏差为1.30%，计算得到本方法 137Cs的探测下限为0.26 Bq/m 3。检测到我国沿海8个省份近海岸海水中 137Cs的活度浓度范围为0.38～1.24 Bq/m 3。与2019年报道我国东部海域海水中 137Cs活度浓度巡测结果(0.03～1.92 Bq/m 3)和太平洋海水中 137Cs活度浓度(1～2 Bq/m 3)相比，我国沿海海水中 137Cs处于本底水平。 结论:本方法具有较高的探测灵敏度，且可快速获得海水中放射性 137Cs的活度浓度，为我国开展海水中放射性 137Cs的应急监测提供了一种快速可行的方法。

abstractsObjective:To establish a highly-sensitive method for the rapid measurement of 137Cs in seawater with an view to its preliminary application in eight coastal provinces of China. Methods:The method employed nickel potassium polyacrylonitrile (KNiFC-PAN), an organic polymer-based ion exchanged resin material, to filter and adsorb 137Cs from seawater at a rate of 60 ml/min via a peristaltic pump. The adsorption efficiency of KNiFC-PAN was determined by measuring the cesium ion concentration before and after adsorption in seawater, with the addition of stable cesium, using inductively coupled plasma mass spectrometry (ICP-MS). Three KNiFC-PAN matrix components of 137Cs standard samples were prepared for the efficiency calibration of well type high purity germanium gamma spectrometer to obtain its detection efficiency. Results:The established measuring method can complete the filtration and adsorption of 137Cs from 20 L seawater within 6-8 h, which was twice as fast as the co-precipitation method with phosphomolybdic acid-ammonium molybdate taking more than 12 h, as stipulated in the GB/T 16145-2022 standard. The cesium recovery rate was as high as 98.02%. The relative standard deviation of the efficiency calibration result for the three prepared standard samples was 1.30%, and the detection limit for 137Cs was 0.26 Bq/m 3. The activity concentrations of 137Cs in offcoast seawater in eight coastal provinces of China were detected ranging from 0.38 to 1.24 Bq/m 3. The activity concentration of 137Cs in coastal seawater of China was at the background level, while as reported in 2019 was 0.03-1.92 Bq/m 3 in the eastern Chinese seas and 1-2 Bq/m 3 in the Pacific Ocean. Conclusions:This method has high detection sensitivity and can quickly obtain the values of activity concentration of 137Cs in seawater, thus providing a rapid and feasible method for emergency monitoring of 137Cs in China.