RAPID: Anthropogenic radionuclides in the Atlantic Ocean 4 decades after GEOSECS

RAPID：GEOSECS 4 年后大西洋中的人为放射性核素

• 批准号: 1012154
• 负责人: Timothy Kenna
• 金额: $ 12.49万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1012154&HistoricalAwards=false
• 关键词: RAPID; Anthropogenic; radionuclides; Atlantic; Ocean

In this project, researchers at the Lamont-Dougherty Earth Observatory of Columbia University will obtain the total concentrations of the anthropogenic radionuclides 239Pu, 240Pu, 237Np, and 137Cs in selected full-depth profiles from the various Atlantic GEOTRACES cruises occurring in 2010 (US, Netherlands, and Germany). This will allow the broad brush characterization of these anthropogenic radionuclides some 37 years after GEOSECS. The isotopes of interest, in addition to being transient tracers, exhibit a range of Kd values (sediment water distribution coefficients, Pu Np ,Cs), and geochemical behaviors as well as provide a means to resolve different sources of radioactive contamination. This will allow the team to address processes such as advection (new water mass tracers), sources and sinks (characteristic isotopic signatures), as well as processes related scavenging and particle dynamics across a range of contrasting regions. The planned US, German, and Dutch GEOTRACES cruises transect regions that represent a full suite of physical and biogeochemical processes that affect TEIs. By comparing radionuclide distributions, isotopic composition, inventories, and inventory ratios of particle reactive (Pu) to conservative (Cs and Np), we will learn first order information about rates of scavenging and transport of these nuclides that is complimentary to that gained through study of other TEIs by GEOTRACES.Since GEOSECS, -- the first and only study to produce a view of the global oceanic distributions of plutonium and 137Cs -- methods have improved requiring less volume and providing not only better sensitivity but additional information (i.e., mass spectrometric techniques are capable of measuring the 240Pu/239Pu atom ratio; traditional alpha spectrometry is not). Where possible, the team will compare distributions measured in 2010 to those measured in 1972-1973 providing a ca. 40-year perspective on processes that control the fate and transport of these contaminants. In addition to providing updated baselines for Pu and 137Cs concentrations in the Atlantic, they will also provide information on 237Np as well as the 240Pu/239Pu isotopic composition, which have not been measured at this scale. Broader Impacts: This project will be an international collaboration and will yield valuable environmental radionuclide data from a number of locations throughout the Atlantic that would not be obtained otherwise. An important problem related to both anthropogenic climate change and sustainability is societal heavy reliance on fossil fuels as the main source of energy. Although the solution will certainly be complex, an increase in the proportion of energy derived from nuclear power is likely. The information gained from this proposal will be useful in assessing the fate of nuclides that might be released as a result of increased reliance on nuclear power in the future.

在该项目中，哥伦比亚大学拉蒙特-道格拉斯地球观测站的研究人员将获得2010年（美国、荷兰和德国）进行的各种大西洋GEOTRACES考察中选定的全深度剖面中人为放射性核素239 Pu、240 Pu、237 Np和137 Cs的总浓度。 这将使人们能够在GEOSECS之后大约37年对这些人为放射性核素进行粗略的定性。感兴趣的同位素除了是瞬时示踪剂之外，还表现出一系列Kd值（沉积物水分配系数、Pu Np、Cs）和地球化学行为，并提供了解决不同放射性污染源的方法。这将使团队能够解决诸如平流（新的水团示踪剂），源和汇（特征同位素签名），以及在一系列对比区域中与清除和粒子动力学相关的过程等过程。 计划中的美国、德国和荷兰GEOTRACES考察代表影响TEI的一整套物理和地球化学过程的样带区域。通过比较放射性核素分布，同位素组成，库存，和粒子反应（钚）的库存比，（Cs和Np），我们将了解这些核素的清除率和迁移率的一阶信息，这与通过GEOTRACES研究其他TEI获得的信息是互补的。这是第一项也是唯一一项了解钚和137 Cs全球海洋分布的研究，方法得到了改进，需要更少的体积，不仅提供了更好的灵敏度，而且提供了更多的信息（即，质谱技术能够测量240 Pu/239 Pu原子比;传统的α光谱法不能）。在可能的情况下，该团队将比较2010年测量的分布与1972-1973年测量的分布，以提供一个ca。40-对控制这些污染物的归宿和迁移过程的年展望。除了提供大西洋钚和137铯浓度的最新基线外，他们还将提供关于237 Np以及240 Pu/239 Pu同位素组成的信息，这些信息尚未在此范围内测量。更广泛的影响：这一项目将是一项国际合作，将从整个大西洋的一些地点获得否则无法获得的宝贵的环境放射性核素数据。 与人为气候变化和可持续性有关的一个重要问题是社会严重依赖化石燃料作为主要能源。虽然解决办法肯定是复杂的，但增加核能发电的比例是可能的。从这一建议中获得的信息将有助于评估今后由于对核能的依赖增加而可能释放的核素的去向。