大洋表层水中~(226)Ra的分布

采用碳酸盐富集－EDTA纯化－Ba（Ra）SO4制源－α计数法，测定了我国第13,14 次南极科学考察期间，从西太平洋、南大西洋和东印度洋采集的 16个表层水样中的226 Ra比活度。测定结果表明，表层水中溶解态226Ra的比活度范围：西太平洋为 0．46──0．95Bq·m－3，平均值为 0．66Bq·m-3；东印度洋为0．5 6──1．2 7 Bq·m-3，平均值为0．81 Bq·m-3；南大西洋为1．17──1．63Bq·m－3，平均值为 1．45 Bq·m－3。还测定了上述海域 5个表层水样中颗粒态226Ra比活度为0.006──0．030Bq·m－3，颗粒态226Ra很低，只占溶解态的1．0％──2．6％，说明226Ra主要以溶解态形式存在于上述洋区。测定结果还表明，52°S以南离南极较近的测站226Ra比活度较高，特别是 60°Ｓ以南的南大洋海域，226Ra比活度更高，与其他作者的测定结果一致。

DISTRIBUTION OF 226Ra IN THE SURFACE WATEROF THE OCEANS

Distributions of 226Ra have been reported in 16 surface water samples from thewestern Pacific, the south Atlantic and the eastern Indian Ocean during the l3th, l4thAntarctic surveys. 226Ra activities are measured by carbonate concentrating,EDTA puri-fication,Ba(Ra) SO4 making source and a counting. The dissolved 226Ra activities rangefrom 0. 46--0. 95 Bq. m--3 with an average of 0. 66 Bq. m -3 for the west Pacific, froml. 1 7 -- 1. 6 3 Bq. m--3 with an average of l. 4 5 Bq. m-3 for the south Atlanticand from0. 56--1. 27 Bq. m-3 with an average of 0. 81 Bq. m-3 for the eastern lndian Ocean.Particulate 226 Ra activities in 5 surface water samples of studied areas range from0. 0060--0. 030 Bq. m-3 with (particulate/ dissolved)A.R. 0. 010--0. 026. Shows thatprimary existing form of 226Ra is dissolved in above mentioned areas. The higher activi-ties of 226Ra were found near the Antarctic. This result is agreement with other investi-gations.