The United States detonated 67 nuclear weapons in the Marshall Islands from 1946 to 1958. While there has been significant study of the aftereffects of these explosions over the decades that followed, few values of strontium-90 (Sr) contamination have been reported. Sediment cores from the Bravo test crater in Bikini Atoll and Lacrosse crater near Runit Island (Enewetak Atoll) were assessed for Sr and cesium-137 (Cs) concentrations, which were found to be measurable in all cores. Sr values were found to be roughly consistent across the tested cores. Ratios of Sr/Cs are elevated compared to values measured previously at other sites of weapons testing and nuclear accidents. These findings suggest the need to further investigate Sr concentrations in the northern Marshall Islands to assess the safety of current residents in light of the potential for Sr conveyance and to provide input regarding resettlement of currently unoccupied islands and atolls.

中文翻译：

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马绍尔群岛北部海洋沉积物中锶 90 的初始浓度

1946 年至 1958 年间，美国在马绍尔群岛引爆了 67 枚核武器。尽管在接下来的几十年里对这些爆炸的后果进行了大量研究，但关于锶 90 (Sr) 污染的报道却很少。对比基尼环礁布拉沃测试陨石坑和鲁尼特岛（埃尼韦塔克环礁）附近的长曲棍球陨石坑的沉积物岩心进行了 Sr 和铯 137 (Cs) 浓度评估，结果发现所有岩心均可测量到这些沉积物。发现所有测试核心的 Sr 值大致一致。与之前在其他武器试验和核事故现场测得的值相比，Sr/Cs 比率有所提高。这些发现表明需要进一步调查马绍尔群岛北部的锶浓度，以根据锶输送的潜力评估当前居民的安全，并为目前无人居住的岛屿和环礁的重新安置提供意见。