K=1 Project, Center for Nuclear Studies, Columbia University, New York, NY 10027.
Department of Chemistry, Columbia University, New York, NY 10027.
Proc Natl Acad Sci U S A. 2019 Jul 30;116(31):15425-15434. doi: 10.1073/pnas.1903421116. Epub 2019 Jul 15.
We report on measurements of external gamma radiation on 9 islands in 4 atolls in the northern Marshall Islands, all of which were affected by the US nuclear testing program from 1946 to 1958 (Enjebi, Ikuren, and Japtan in Enewetak Atoll; Bikini and Enyu in Bikini Atoll; Naen in Rongelap Atoll; and Aon, Elluk, and Utirik in Utirik Atoll). We also report americium-241, cesium-137, plutonium-238, and plutonium-239,240 activity concentrations in the soil samples for 11 islands in 4 northern atolls (Enewetak, Japtan, Medren, and Runit in Enewetak Atoll; Bikini and Enyu in Bikini Atoll; Naen and Rongelap in Rongelap Atoll; and Aon, Elluk, and Utirik in Utirik Atoll) and from Majuro Island, Majuro Atoll in the southern Marshall Islands. Our results show low external gamma radiation levels on some islands in the Enewetak Atoll and Utirik Atoll, and elevated levels on Enjebi Island in the Enewetak Atoll, on Bikini Atoll, and on Naen Island in the Rongelap Atoll. We perform ordinary kriging on external gamma radiation measurements to provide interpolated maps. We find that radionuclides are absent from all Majuro soil samples, and that they are present at highest activity concentrations in samples from Runit and Enjebi islands (Enewetak Atoll), Bikini Island (Bikini Atoll), and Naen Island (Rongelap Atoll). We contextualize all results by making comparisons between islands and to various standards, as well as to regions of the world affected by nuclear accidents. We also discuss implications for informed decision-making by the Marshallese and local atoll governments and their people on issues pertaining to island resettlement.
我们报告了对马绍尔群岛北部 4 个环礁中的 9 个岛屿的外部伽马辐射测量结果，这些岛屿都受到了美国从 1946 年到 1958 年的核试验计划的影响（埃尼威托克环礁中的恩杰比、伊库伦和雅普坦；比基尼环礁中的比基尼和埃尼乌；朗格拉普环礁中的纳恩；以及乌特里克环礁中的阿翁、埃勒克和乌提里克）。我们还报告了在 4 个北部环礁的 11 个岛屿（埃尼威托克环礁中的埃梅雷克、雅普坦、梅德伦和鲁尼特；比基尼环礁中的比基尼和埃尼乌；朗格拉普环礁中的纳恩和朗格拉普；以及乌特里克环礁中的阿翁、埃勒克和乌提里克）以及马绍尔群岛南部的马久罗岛的土壤样本中钚-238、钚-239、240 和铯-137、镅-241 的活度浓度。我们的结果表明，在埃尼威托克环礁和乌特里克环礁的一些岛屿上，外部伽马辐射水平较低，而在埃尼威托克环礁的恩杰比岛、比基尼环礁和朗格拉普环礁的纳恩岛上，外部伽马辐射水平较高。我们对外部伽马辐射测量结果进行普通克里金插值，以提供插值图。我们发现，马久罗的所有土壤样本中都没有放射性核素，而在鲁尼特和恩杰比岛（埃尼威托克环礁）、比基尼岛（比基尼环礁）和纳恩岛（朗格拉普环礁）的样本中，放射性核素的活度浓度最高。我们通过岛屿之间的比较以及与世界上受核事故影响的地区的比较，对所有结果进行了背景分析。我们还讨论了这些结果对马绍尔群岛和当地环礁政府及其人民在岛屿重新安置问题上做出明智决策的影响。
