著者
友寄 喜貴 棚原 朗 武村 盛久 渡口 輝 平良 初男
出版者
日本地球化学会
雑誌
地球化学 (ISSN:03864073)
巻号頁・発行日
vol.31, no.4, pp.227-233, 1997
被引用文献数
3

The activities of natural radionuclides, <sup>238</sup>U, <sup>234</sup>U, <sup>226</sup>Ra, <sup>228</sup>Ra, <sup>222</sup>Rn, <sup>210</sup>Pb and <sup>210</sup>Po in ground waters collected from Okinawa Island were measured. The <sup>234</sup>U/<sup>238</sup>U activity ratios in most samples showed more or less unity, whereas, relatively high values of 2.0-4.0 were obtained in samples from Motobu area. <sup>222</sup>Rn activities in the ground waters were much higher than the other uranium series nuclides. The <sup>222</sup>Rn/<sup>226</sup>Ra activity ratios ranged from 3000 to 29000, and those for <sup>210</sup>Po/<sup>210</sup>Pb were from 0.08 to 0.82. On the whole, activities of the nuclides in the ground waters at the studied points showed higher in the order of <sup>222</sup>Rn≫<sup>210</sup>Pb><sup>234</sup>U><sup>238</sup>U><sup>226</sup>Ra><sup>210</sup>Po. In addition to α_recoil dissolution, the selective absorption and/or desorption by some organic or inorganic substances in the aquifer may be happening.