Illustration by Etienne Cipriani
After the atomic explosion over Hiroshima
many survivors feared that nothing would grow on the decimated earth. When the spring of 1946 arrived, the people of Hiroshima were surprised to find the landscape dotted with the blooming red petals of the oleander. The oleander flower, called kyochikuto in Japanese, allayed fears that the destroyed city had lost all of its fertility and raised hopes among the population that Hiroshima would soon recover from the tragic bombing raids.
Today the oleander is the official flower of Hiroshima and is a beautiful symbol for the whole city; While some feared the city and its people would be irreparably destroyed - permanently cut off from normalcy by the effects of radiation - many would be surprised to learn of the limited long-term health effects of the nuclear attacks on Hiroshima and Nagasaki in August 1945.
In the first few months after the bombing, between 90,000 and 166,000 people died in Hiroshima, and another 60,000 to 80,000 in Nagasaki.
According to estimates by the Radiation Effects Research Foundation (a cooperative Japanese-American organization), between 90,000 and 166,000 people died in Hiroshima and another 60,000 to 80,000 in Nagasaki in the first few months after the bombing. These deaths include those who died from the force and excruciating heat of the explosions and deaths from acute radiation exposure.
While these numbers are inaccurate estimates - due to the fact that it is not known how many slave laborers and military personnel were in the city and that in many cases entire families were killed and no one was able to report the deaths - they are long-term impact statistics were even more difficult to determine.
Although radiation exposure can have an acute, almost immediate effect, killing cells and directly damaging tissues, radiation can also have longer-term effects, such as: B. Cancer by causing mutations in the DNA of living cells. Mutations can occur spontaneously, but mutagenic radiation increases the likelihood that a mutation will occur. In theory, ionizing radiation can deposit energy to break molecular bonds that can damage DNA and thus alter genes. In response, a cell either repairs the gene, dies, or maintains the mutation. In order for a mutation to cause cancer, a number of mutations must likely accumulate in a particular cell and its offspring. For this reason, it can take many years after exposure for an increase in cancer incidence rate to be seen from radiation.
Damage map in Hiroshima
Of the long-term effects that atomic bomb survivors suffered, leukemia was the deadliest. An increase in leukemia occurred about two years after the seizures and peaked about four to six years later. Children are the most affected population. The attributable risk - the percentage difference in the incidence rate of a disease between an exposed and a comparable non-exposed population - shows how strongly radiation influences the incidence of leukemia. The Radiation Effects Research Foundation estimates the attributable risk of leukemia for bomb victims to be 46%.
For all other cancers, the incidence did not increase until about ten years after the seizures. The increase was first noted in 1956, and tumor registries were opened soon after in both Hiroshima and Nagasaki to collect data on the increased cancer risks caused by radiation exposure. The most thorough study of the incidence of solid cancer (i.e., cancer that is not leukemia) was conducted by a team led by Dale L. Preston of Hirosoft International Corporation and published in 2003 was significantly lower than leukemia - 10.7%. Sea RERF , the data confirms the general rule that even if someone is exposed to a barely survivable dose of whole-body radiation, the solid risk of cancer is no more than five times greater than the risk of an unexposed person.
Almost seventy years after the bombings, most of the generation who lived during the attack have died. Much more attention is now being paid to the children of the survivors. In people who were exposed to radiation before birth ( in utero ), Studies such as one by E. Nakashima in 1994 , showed that exposure resulted in an increase in the small head size and intellectual disability, as well as impaired physical growth. Exposed people in utero The cancer rate was also found to be lower than survivors who were children at the time of the attack.
One of the most pressing concerns about the future of Hiroshima and Nagasaki after the attacks was the health impact of radiation on the children of survivors conceived after the bombings. So far , no radiation-related disease excess was found in the children of survivors, although more time is needed to know for sure. In general, however, the health of the new generations in Hiroshima and Nagasaki gives confidence that cities like the oleander flower will continue to rise from their past destruction.
The pilot of the Enola Gay, Paul Tibbets, took this picture of the aftermath.
Perhaps most comforting is the view of the cityscapes themselves. Among some, there is an unfounded fear that Hiroshima and Nagasaki are still radioactive; in reality this is not true. There are two forms of residual radioactivity after a nuclear explosion. The first is the fallout of the nuclear material and the fission products. Most of it was scattered in the atmosphere or blown in the wind. Although some fell on the city as black rain, the radioactivity is today so low that it can hardly be distinguished from the trace amounts available worldwide as a result of atmospheric tests in the 1950s and 1960s. The other form of radiation is neutron activation. Neutrons can cause non-radioactive materials to become radioactive when captured by atomic nuclei. However, because the bombs were detonated so far above the ground, there was very little contamination - especially in contrast to nuclear test sites like those in Nevada. In fact, almost all of the induced radioactivity decayed within a few days of the explosions.
Today, the vibrancy of the cities of Hiroshima and Nagasaki is a reminder not only of human regeneration, but also of the extent to which fear and misinformation can lead to false expectations. After the Hiroshima and Nagasaki bombings, many believed that any city hit by a nuclear weapon would become a nuclear wasteland. While the immediate aftermath of the atomic bombing was horrific, nightmarish, and left untold, the peoples of Hiroshima and Nagasaki did not allow their cities to become what some thought was inevitable. This experience can serve as a Lesson in the present If much of the public and even some governments reacted radically to the accident in Fukushima - amid tragedy, hope remains for the future.
- The Radiation Effects Research Foundation website outlines the results of numerous studies on the survivors of Hiroshima and Nagasaki .
- The Hiroshima Peace Memorial Museum website discussesoshi the reconstruction efforts of Hiroshima City after the atomic bombing .
- A study by Hirosoft International analyzed the incidence of solid cancer in atomic bomb survivors .
- in the The Children of Atomic Bomb Survivors: A Genetic Study the author overview a series of studies on children of parents who have been exposed to atomic bombs .
D. L. Preston, E. Ron, S. Tokuoka, S. Funamoto, N. Nishi, M. Soda, K. Mabuchi und K. Kodama (2007) Solid cancer incidence in atomic bomb survivors: 1958-1998 . Radiation Research 168: 1, 1-64
E. J. Grant, K. Ozasa, D. L. Preston, A. Suyama, Y. Shimizu, R. Sakata, H. Sugiyama, T-M. Pham, J. Cologne, M. Yamada, A.J. De Roos, K.J. Kopecky, M.P. Porter, N. Seixas und S. Davis. (2012) Effects of radiation and lifestyle factors on urothelial cancer risk in the life-span study of atomic bomb survivors . Radiation research 178: 1, 86-98
'Effects of Radiation on Health'. - Foundation for radiation effects research . Foundation for Radiation Effects Research, 2007. Web. July 29, 2012.
W. F. Heidenreich, H. M. Cullings, S. Funamoto und H. G. Paretzke. (2007) Promote radiation effect in carcinogenesis data of atomic bomb survivors? . Radiation research 168: 6, 750-756Tags Hiroshima Nagasaki