Cs-134, Cs-137, and I-129 dissolved in seawater im MR20-05C

(1) Radiocesium (Cs-134 and Cs-137)Seawater samples for radiocesium were collected using 12-liter PVC bottles. Surface seawater was collected from continuous pumped-up water at about 4-m depth. The sample volumes is 40 L (two 20-L plastic containers).The seawater sample for radiocesium measurement was not filtered and was acidified by adding nitric acid. Radiocesium in the seawater sample is concentrated using ammonium phosphomolybdate (AMP) that forms an insoluble compound with cesium. The radiocesium in the compound is measured using Ge gamma-ray spectrometers. We collected 34 seawaters for the radiocesium measurements in the Arctic Ocean, Bering Sea, and northern North Pacific Ocean during this cruise.(2) I-129Seawater samples for 129I were collected using 12-liter PVC bottles. Surface seawater was collected from continuous pumped-up water at about 4-m depth. The seawater sample was collected into a 1-L plastic bottle after two-time rinsing. Iodine in the seawater samples is extracted by the solvent extraction technique. Extracted iodine is then precipitated as silver iodide by the addition of the silver nitrate. Iodine isotopic ratios (I-129/I-127) of the silver iodide are measured by the Accelerator Mass Spectrometry (AMS). To evaluate the I-129 concentration in the seawater samples, iodine concentration (I-127) will be measured by the inductively coupled plasma mass spectrometry (ICP-MS) and/or the voltammetry. We collected 80 seawater samples for I-129 measurements in the Arctic Ocean, Bering Sea, and northern North Pacific Ocean during this cruise.(1) 放射性铯（Radiocesium，Cs-134与Cs-137）相关海水样品：采用12升聚氯乙烯（PVC）瓶采集海水放射性铯样品。表层海水采集自约4米深度的连续抽汲水体。样品总体积为40升（分装为两个20升塑料容器）。用于放射性铯检测的海水样品未经过滤，通过添加硝酸完成酸化处理。海水中的放射性铯可通过磷钼酸铵（ammonium phosphomolybdate，AMP）实现富集，该试剂可与铯结合形成不溶性化合物。随后采用锗伽马射线能谱仪（Ge gamma-ray spectrometers）对该化合物中的放射性铯进行定量检测。本次航次期间，我们在北冰洋、白令海及北太平洋北部海域共采集了34份用于放射性铯检测的海水样品。(2) 碘-129（I-129）相关海水样品：采用12升聚氯乙烯（PVC）瓶采集海水129碘样品。表层海水采集自约4米深度的连续抽汲水体。将海水经两次润洗后收集至1升塑料瓶中。采用溶剂萃取技术提取海水中的碘。萃取得到的碘随后通过添加硝酸银沉淀为碘化银。通过加速器质谱（Accelerator Mass Spectrometry，AMS）测定碘化银的碘同位素比值（I-129/I-127）。为评估海水样品中的129碘浓度，将通过电感耦合等离子体质谱（inductively coupled plasma mass spectrometry，ICP-MS）及/或伏安法测定碘浓度（I-127）。本次航次期间，我们在北冰洋、白令海及北太平洋北部海域共采集了80份用于129碘检测的海水样品。