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本文对中国７个近岸海域沉积物２２６Ｒａ的分布进行了研究，结果表明珠江口表层沉积物的２２６Ｒａ含量较高，其余６个近岸海域（黄河口、胶州湾、长江口、杭州湾、厦门湾、大亚湾）的２２６Ｒａ含量相近．２２６Ｒａ含量值显示了研究海域沉积物的“亲陆性”，但不同站位２２６Ｒａ含量受物源区域、水动力作用及其他环境理化诸因素的影响．２２６Ｒａ在况积物盐酸沥取相的放射性比度及总量均大于残渣相的相应数值，说明陆源物质在风化及向海迁移过程中绝大部分镭进入到水相中．元洪码头附近海域岩心中２２６Ｒａ的垂直分布表明，镭发生了沉积后的再迁移．所有各相的活度比（２２６Ｒａ／２３８Ｕ）ａ．ｒ、（２２６Ｒａ／２３０Ｔｈ）ａ．ｒ．均小于１．０，进一步证明中国近岸沉积物普遍存在２２６Ｒａ－２３８Ｕ、２２６Ｒａ－２３０Ｔｈ不平衡现象．
In this paper, the distribution of sediment 226Ra in seven coastal waters of China was studied. The results showed that the 226Ra content of surface sediments in the Pearl River estuary was high, while the remaining six coastal waters (Yellow River, Jiaozhou Bay, Changjiang River, Hangzhou Bay, Xiamen Bay, Daya Bay) 226Ra content similar. The value of 226 Ra shows the “delustering” of sediments in the study area, but the content of 226 Ra in different stations is affected by the source area, hydrodynamic effect and other environmental factors. 226Ra leaching in the leachate of the leachate is greater than that of the leachate phase, indicating that most of the radium of terrestrial material migrates into the water phase during weathering and migration to the sea. The vertical distribution of 226Ra in the cores near the wharf at Yuanhong indicates that redeposition of radium occurs after sedimentation. Activity ratio of all phases (226Ra / 238U) a. r, (226Ra / 230Th) a. r Are all less than 1.0, which further proves that imbalances of 226Ra-238U and 226Ra-230Th are common in the coastal sediments of China.