渤、黄、东、南海沉积物中^(226)Ra的含量比较

A COMPARISON OF CONTENTS OF ^(226)Ra IN SEDIMENTS IN THE WATERS OF THE BOHAI, HUANGHAI, EAST CHINA AND SOUTH CHINA SEAS

我们测定了渤海、黄海、东海和南海沉积物中^(226)Ra的含量,从所测结果表明:四大海区的所有近岸河口区,^(226)Ra的含量都小于0.017Bq/g,而南海中部的深海区,^(226)Ra的含量基本上都大于0.017Bq/g。另一方面,在近岸河口区,^(226)Ra的含量也有差别,其中珠江口最低,为0.006Bq/g;九龙江口最高,为0.014Bq/g;长江口、黄海和渤海三个海区,^(226)Ra的含量基本相等,即在0.012～0.013Bq/g之间。这些现象说明,在近岸河口区^(226)Ra主要来源于陆源物质;在深海区^(226)Ra主要来源于海底沉积物中^(230)Th的衰变产物,这种规律和世界其他海区基本一致。

The authors have determined contents of ^(226)Ra in, sediments in the waters of the Bohai, Huanghai, East China and South China Seas. The results show that the content of ^(226)Ra is less than 0.07/Bq/g in offshore and estuarine waters, but more than 0.017Bq/g in the South China Sea. Some difference of the content of ^(226)Ra in offshore and estuarine waters, in which the content (0.006 Bq/g) in the Zhujiang River Estuary, the highest content (0.014 Bq/g) in the Jiulong River Estuary, but that in the Changjing River Estuary is basically equal to that in the Huanghai and Bohai Seas, i. e. (0.012～0.013 Bq/g). It is shown that, the ^(226)Ra in offshore and estuarine waters comes mainly from terrigenous material, but ^(226)Ra in the deepsea comes from the decay products of ^(230)Th. This regular pattern is basically in agreement with that in other sea areas of the world.