Spatial variations of 226Ra, 228Ra, 137Cs, and 228Th activities in the southwestern Okhotsk Sea
Spatial variations of 226Ra, 228Ra, 137Cs, and 228Th activities in the southwestern Okhotsk Sea
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DOI：
10.1016/j.jenvrad.2011.09.007
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发表时间：
2012-02-01
影响因子：
2.3
通讯作者：
Yamamoto, Masayoshi
中科院分区：
文献类型：
--
作者：
Inoue, Mutsuo;Yoshida, Keisuke;Yamamoto, Masayoshi
我们采集了鄂霍次克海西南部的14个海水样品和日本北方北海道北方附近的7个表层样品，采用低本底γ能谱法和简便的最小放化处理方法测定了Ra-226的活度（半衰期t（1/2）= 1600 y）、Ra-228（5.75 y）、Cs-137（30.2 y）和Th-228（1.91 y）。Ra-226的活性（类似于2.3 mBq/L），Ra-228（类似于0.7 mBq/L）和Cs-137鄂霍次克海一侧的表层沃茨中的放射性活度（类似于1 mBq/L）与日本海一侧的有显著差异（大豆暖流水; SWCW）（类似于1.5 mBq/L; 1.5-2 mBq/L; 1.4-1.6 mBq/L），表明它们的不同起源和横向混合模式。所有这些核素都表现出独特的垂直分布;可溶性Ra-226、Ra-228、Cs-137和活性Th-228的放射性在50至500米深度之间表现出微小的变化（Ra-226，2.2 mBq/L; Ra-228，0.4 mBq/L; Cs-137，类似于1 mBq/L; Th-228，类似于0.13 mBq/L）。这些配置文件可以解释的对流混合的地表水，如东萨哈林海流水（ESCW）到这一层。(C)2011爱思唯尔有限公司保留所有权利。
We collected 14 water column seawater samples in the southwestern Okhotsk Sea and 7 surface samples around the northern area of Hokkaido Island, Northern Japan, and employed low-background gamma-spectrometry with convenient minimal radiochemical processing to determine the activities of Ra-226 (half-life t(1/2) = 1600 y), Ra-228 (5.75 y), Cs-137 (30.2 y), and Th-228 (1.91 y) in the samples. Activities of Ra-226 (similar to 2.3 mBq/L), Ra-228 (similar to 0.7 mBq/L), and Cs-137 (similar to 1 mBq/L) of surface waters on the Okhotsk Sea side show notable differences from those on the Japan Sea side (Soya Warm Current Water; SWCW) (similar to 1.5 mBq/L; 1.5-2 mBq/L; 1.4-1.6 mBq/L), indicating their different origins and lateral mixing patterns. All of these nuclides exhibit unique vertical profiles; activities of soluble Ra-226, Ra-228, Cs-137, and reactive Th-228 exhibit small variations from 50 to 500 m depth (Ra-226, 2.2 mBq/L; Ra-228, 0.4 mBq/L: Cs-137, similar to 1 mBq/L; Th-228, similar to 0.13 mBq/L). These profiles can be explained by the convective mixing of surface water such as the East Sakhalin Current Water (ESCW) to this layer. (C) 2011 Elsevier Ltd. All rights reserved.