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Friday, 18-Aug-2017 10:58:47 GMT
Radiation and the biota

High levels of radiation hampered the study of the effects of radiation in the effected areas. When the tests began, no one really knew how dangerous radiation was nor how insidiously difficult it was to get rid of. So, in the early testing, aside from sunglasses, observers sat back in their easy-chairs to watch history unfold. It was assumed they were at a safe distance - and that the test ships could easily be scrubbed down and would be decontaminated that way. But after the second lest, "Baker", the levels of radiation were so high - and were remaining that way - that a hasty retreat of all personnel from Bikini was ordered, not to return for 8 years.

Baker nuclear blast on Bikini
"Baker" blast - 1946

It was 10 years later, in 1956. that noted botanist F. R. Fosberg was able to visit several of the irradiated islands. But even then he realized that "the vegetation on some of the islets visited was not normal." Yet because he realized that previous to this "no serious attention was paid to these abnormal phenomena" and felt that it was already "too late to make any systemic study."

He did observe that "kalane" (Suriana maritima) suffered greatly, being found in a dead or dying state, and "kanal" was abnormally defoliated. Even hardy grasses seem to have suffered. And although "kiden" and "kannat" appeared unaffected at that time, later studies indicated that even these harbored measurable levels of radioactivity.

In order to try better understand the aftereffects of the bombs, the Enewetak Marine Biological Laboratory was established in 1954. It was in operation there for 30 years and produced volumes of information about all aspects of the environment. Follow-up research on a less intensive scope was conducted on Bikini and other irradiated atolls.

Through these and other studies, it is now known that different components of radioactive materials have a wide range of characteristics. Different plant species absorb these elements at different rates. And radioactive material passes down through the food web. "Liit" (lichens), for example, are very tolerant of radioactivity. While used traditional, people do not depend on "liit" for food.

A major part of the research has centered on food crops and animals. Coconuts have been found to retain a significant amount of Cesium-137. Hence when coconut crabs eat coconuts, Cesium-137 builds up in their bodies. In a similar fashion, when people eat coconuts - or coconut crabs - the risks of radiation buildup and related sicknesses increase. Other plants tested show certain levels of radioactivity but are used as local medicine, and not food, so the extensive studies considered them to be safe.

While all these studies have gone on, the most irradiated atolls were declared uninhabitable by humans. This was appropriately done for the sake of safety to people. Although this has caused much heartache to the displaced people, it has allowed the land to recolonize itself. Gradually, even though the soil was still radioactive and often blasted clear of all vegetation, plants began to return following a pattern fairly similar to what has been theorized to have originally occurred throughout all of the Marshal Islands untold centuries ago.

Birds, similarly, returned in abundance, nesting safely away from human pressure. The reappearance of large nesting colonies is figured to play an important part not only in accelerating the entire recolonization process on the affected islands, but also in understanding the recovery of atoll communities. Nevertheless, richer soils retain radioactive material more than poor sandy or gravelly soils, so much of the soil has retained radioactivity.

The resettlement of plants and animals on the land has, in general, been considered to be so complete that when the option of scraping the land to remove residual radiation before human reoccupation, although favored by the islanders, some scientists have voiced concern. These prefer the use of potassium fertilizer, which they say would he absorbed by plants in preference to Cesium-137. The concern is that scraping would destroy the plants and the bird-nesting habitats.

Underwater, the aftereffects of the thermonuclear tests have also been studied, but again, often at a time later than would have yielded the best results. Fishes - shore and open ocean - especially food fishes, have been studied for their levels of several radioactive elements, especially Plutonium 239+240. Concentrations were always higher in the liver than in the bone, with ihe concentrations being even lower in the muscles. In a report on fishes collected from 1976-1978, the conclusion that the researchers V. E. Noshin. R. J. Eagle. K. M. Wong and T. A. Jokela from the Lawrence Livermore National Laboratory came to was, that still the "current understanding of factors that influence the uptake of 239+240 Pu [Plutonium by some species at an atoll are not adequate to explain the present results."

The natural process of siltation within lagoons of the atolls initially was expected to help bury much in the way of radioactive material. However, certain species of marine animals pump up fine grained sediment (which holds the highest radionuclide levels) to the surface of lagoon bottoms, potentially keeping the contaminants in the food chain. Recent reports claim that fishes from the affected atolls do not pose any risks to people, a fact that workers and preliminary visitors to Rongelap seem to be using to their benefit as they thrill at the excitement of fishing again in that atoll's lagoon.

Indeed, the atolls that were uninhabited for so long due to radiation are now being visited by more than scientists. When National Geographic magazine featured an article on Rongelap in April 1998 it was observed that "the nuclear blasts that rocked this region seem to have had no long-term impact on the marine life." James Delgado similarly observed in his book, Ghoust Fleet, that on Bikini, there was "no tangible evidence of the testing."

Unfortunately, the complete picture of nuclear testing on the Marshalls' biodiversity is not all that simple nor is it necessarily as it seems to casual observers. As R. A. Kenchington and B. Salvat stated in their discussion on all threats to the coral reefs, "Radioactive wastes may have long-term and largely unpredictable effects upon the genetic nature of the biological community." Risks from the consumption of large amounts of locally grown food are still acknowledged to exist, even though people returning to some of these atolls are again eating coconut crabs. Although almost a half century has passed, the full extent of this major effect of people on the biota - the radiation and radioactive materials that came through the nuclear testing program - are not certain.


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bulletHOME bullet NEWSbullet OVERVIEW OF LOCAL BIODIVERSITY bullet NATIONAL IMPLEMENTATION bullet NATIONAL INITIATIVES bullet PUBLICATIONS bullet THREATS TO BIODIVERSITY:[ Introduction ::: Invasive species ::: Case 1: snails... ::: Case 2: invasions of plants ::: Case 3: ants - environmental disasters ::: Changes in population and lifestyle ::: Case: albatrosses and man ::: Nuclear testing and the biota ::: you are hereCase: radiation and the biota ::: Climate change ] bullet RMI NATURAL RESOURCES DATABASE bullet MISC. DATASETS AND MAPSbullet PARTNERS AND LINKS bullet CONTACTS bullet FEEDBACK bullet COPYRIGHT bullet ACCESSIBILITY bullet DISCLAIMER bullet PRIVACY bullet
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