#Radiation #maps of #ocean #sediment from the Castle Bravo #crater (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Radiation maps of ocean sediment from the Castle Bravo crater

Emlyn W. Hughes, Monica Rouco Molina, Maveric K. I. L. Abella, Ivana Nikolić-Hughes, and Malvin A. Ruderman

PNAS first published July 15, 2019 / DOI: https://doi.org/10.1073/pnas.1903478116

Contributed by Malvin A. Ruderman, May 14, 2019 (sent for review March 1, 2019; reviewed by David Kawall and Yury G. Kolomensky)

Related Articles: In situ measurement of cesium-137 contamination in fruits from the northern Marshall Islands – Jul 10, 2019; Background gamma radiation and soil activity measurements in the northern Marshall Islands – Jul 10, 2019



High-yield thermonuclear explosions cause enormous radioactive contamination to the environment. These “hydrogen bombs,” when tested on small islands in the ocean, vaporize the land and produce radionuclides that settle in the ocean sediment. Even decades later, significant contamination may remain in the sediment surface and deep into the sediment layers. Measuring the radioactive contamination of the crater sediment is a first step in assessing the overall impact of nuclear weapons testing on the ocean ecosystems. We find radiation levels orders of magnitude above background for plutonium-(239,240), americium-241, and bismuth-207 in the top 25 cm of sediment across the entire Bravo bomb crater, the location of the largest aboveground US nuclear weapons test.



On March 1, 1954, the United States conducted its largest thermonuclear weapon test in Bikini Atoll in the Marshall Islands; the detonation was code-named “Castle Bravo.” Radioactive deposits in the ocean sediment at the bomb crater are widespread and high levels of contamination remain today. One hundred thirty cores were collected from the top 25 cm of surface sediment at ocean depths approaching 60 m over a ∼2-km2 area, allowing for a presentation of radiation maps of the Bravo crater site. Radiochemical analyses were performed on the following radionuclides: plutonium-(239,240), plutonium-238, americium-241, bismuth-207, and cesium-137. Large values of plutonium-(239,240), americium-241, and bismuth-207 are found. Comparisons are made to core sample results from other areas in the northern Marshall Islands.

Bravo crater – Bikini Island – cesium-137 – ocean sediment – plutonium

Keywords: Environmental pollution; Environmental disasters; Radiations; Radionuclides; Marshall Islands.


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Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.