Most of the samples that have passed across Hasegawa's desk have proved to be within the legal consumption limit of the radioactive isotopes cesium 134 and 137 and iodine 131.

摆放在长谷川桌子上的大部分检测样品，都被证明所含的放射性元素铯- 134，铯- 137和碘- 131均在可安全范围内。

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But cesium-134, which has a half-life of only two years, clearly came from the meltdowns, the researchers say.

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It uses two ion exchange processes to remove the radioactive elements Cesium-134 (Cs-134), Cesium-137 (Cs-137) and Strontium-90 (Sr-90) from the seawater.

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Two types of trace radiation have been found, iodine-131, and cesium-134.

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