Radiation doses and cancer risks in the Marshall Islands associated with exposure to radioactive fallout from Bikini and Enewetak nuclear weapons tests: summary.
Radiation doses and cancer risks in the Marshall Islands associated with exposure to radioactive fallout from Bikini and Enewetak nuclear weapons tests: summary.
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DOI：
10.1097/hp.0b013e3181dc523c
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发表时间：
2010-08
期刊：
影响因子：
2.2
通讯作者：
Beck HL
中科院分区：
文献类型：
--
作者：
Simon SL;Bouville A;Land CE;Beck HL
1946年至1958年期间在比基尼和埃尼威托克环礁进行的核武器试验使今天的马歇尔群岛共和国的居民受到放射性沉降物的照射。本文总结了一个彻底的和系统的重建辐射剂量的人口，按年，暴露的年龄，居住的环礁，以及相关的癌症风险的结果。详细的方法和结果在本卷的一系列配套文件中介绍。根据我们的分析，我们得出的结论是，在马歇尔群岛境内或附近进行的66次核试验中，有20次在马歇尔群岛的一个或多个有人居住的环礁上造成了可测量的沉降物沉积。在这项工作中，我们估计了马歇尔群岛32个环礁和独立礁岛上所有重要剂量贡献放射性核素的沉积密度（kBq m−2）。对每个环礁每次试验产生的63种放射性核素进行了定量沉积估计。这些估计值沿着报告的沉降物后不同时间的照射率测量值被用来估计环礁居民的红骨髓、甲状腺、胃壁和结肠壁从外部和内部照射中吸收的辐射剂量。估计了从新生儿到成人的六个年龄组的年剂量。我们发现，137 Cs的总沉积，外部剂量，内部器官剂量和癌症风险遵循相同的地理模式，南部环礁的大量人口接受最低剂量。在试验期开始时，南部环礁岛成年常住居民所受的外照射剂量平均为5至12 mGy;中纬度环礁岛成年人所受的外照射剂量平均为22至59 mGy，而北方环礁岛居民所受的外照射剂量为数百至1 000 mGy以上。内照射剂量因受照年龄、地点和器官而有显著差异。除了甲状腺的内部剂量外，外部照射通常是器官剂量的主要贡献者，特别是红骨髓和胃壁。胃壁和红骨髓的内部剂量大小相似，南部和中纬度环礁永久居民的剂量约为1 mGy至7 mGy。然而，北方环礁的一部分Utrik和Rongelap岛的成年居民受到的体内剂量要高得多，因为他们摄入了短寿命放射性核素，导致红骨髓和胃壁受到的剂量从20 mGy到500 mGy以上。一般而言，结肠壁的内照射剂量是红骨髓的4至10倍，甲状腺的内照射剂量是红骨髓的20至30倍。Utrik社区和Rongelap岛社区的成人甲状腺内部剂量分别约为760 mGy和7，600 mGy。在1954年3月1日进行Castle Bravo试验时，朗格拉普岛上幼儿甲状腺受到的剂量最高，约为成人的三倍。与长寿命放射性核素在环境中的残留活性有关的长期摄入的体内剂量，一般来说，与沉降物沉积后立即或不久摄入放射性核素造成的急性照射相比，是较低的。每年的剂量和每个环礁岛的人口规模被用来估计在试验期间居住的所有环礁岛的永久居民以及在试验之前或试验开始之后迁移的马绍尔群岛人口群体的癌症风险。预计在25 000多名马绍尔人中将出现大约170个额外的癌症（与辐射有关的病例），其中一半是1948年以前出生的。据估计，除了大约65种癌症之外，所有这些癌症都已经表达。在同一批马绍尔人中，170个多余的癌症与大约10 600个自发产生的癌症相比，这些癌症与放射性沉降物无关。
Nuclear weapons testing conducted at Bikini and Enewetak Atolls during 1946–1958 resulted in exposures of the resident population of the present-day Republic of the Marshall Islands to radioactive fallout. This paper summarizes the results of a thorough and systematic reconstruction of radiation doses to that population, by year, age at exposure, and atoll of residence, and the related cancer risks. Detailed methods and results are presented in a series of companion papers in this volume. From our analysis, we concluded that 20 of the 66 nuclear tests conducted in or near the Marshall Islands resulted in measurable fallout deposition on one or more of the inhabited atolls of the Marshall Islands. In this work, we estimated deposition densities (kBq m−2) of all important dose-contributing radionuclides at each of the 32 atolls and separate reef islands of the Marshall Islands. Quantitative deposition estimates were made for 63 radionuclides from each test at each atoll. Those estimates along with reported measurements of exposure rates at various times after fallout were used to estimate radiation absorbed doses to the red bone marrow, thyroid gland, stomach wall, and colon wall of atoll residents from both external and internal exposure. Annual doses were estimated for six age groups ranging from newborns to adults. We found that the total deposition of 137Cs, external dose, internal organ doses, and cancer risks followed the same geographic pattern with the large population of the southern atolls receiving the lowest doses. Permanent residents of the southern atolls who were of adult age at the beginning of the testing period received external doses ranging from 5 to 12 mGy on average; the external doses to adults at the mid-latitude atolls ranged from 22 to 59 mGy on average, while the residents of the northern atolls received external doses in the hundreds to over 1,000 mGy. Internal doses varied significantly by age at exposure, location, and organ. Except for internal doses to the thyroid gland, external exposure was generally the major contributor to organ doses, particularly for red bone marrow and stomach wall. Internal doses to the stomach wall and red bone marrow were similar in magnitude, about 1 mGy to 7 mGy for permanent residents of the southern and mid-latitude atolls. However, adult residents of Utrik and Rongelap Island, which are part of the northern atolls, received much higher internal doses because of intakes of short-lived radionuclides leading to doses from 20 mGy to more than 500 mGy to red bone marrow and stomach wall. In general, internal doses to the colon wall were four to ten times greater than those to the red bone marrow and internal doses to the thyroid gland were 20 to 30 times greater than to the red bone marrow. Adult internal thyroid doses for the Utrik community and for the Rongelap Island community were about 760 mGy and 7,600 mGy, respectively. The highest doses were to the thyroid glands of young children exposed on Rongelap at the time of the Castle Bravo test of 1 March 1954 and were about three times higher than for adults. Internal doses from chronic intakes, related to residual activities of long-lived radionuclides in the environment, were, in general, low in comparison with acute exposure resulting from the intakes of radionuclides immediately or soon after the deposition of fallout. The annual doses and the population sizes at each atoll in each year were used to develop estimates of cancer risks for the permanent residents of all atolls that were inhabited during the testing period as well as for the Marshallese population groups that were relocated prior to the testing or after it had begun. About 170 excess cancers (radiation-related cases) are projected to occur among more than 25,000 Marshallese, half of whom were born before 1948. All but about 65 of those cancers are estimated to have already been expressed. The 170 excess cancers are in comparison to about 10,600 cancers that would spontaneously arise, unrelated to radioactive fallout, among the same cohort of Marshallese people.