General Effects of the Atomic Bombs: Radiation disease

General Effects of the Atomic Bombs brought about Radiation disease on the populace. The radiation effects upon survivors resulted from the gamma rays liberated by the fission process rather than from induced radio-activity or the lingering radio-activity of deposits of primary fission products. Both at Nagasaki and at Hiroshima, pockets of radio-activity have been detected where fission products were directly deposited, but the degree of activity in these areas was insufficient to produce casualties. Similarly, induced radio-activity from the interaction of neutrons with matter caused no authenticated fatalities. But the effects of gamma rays—here used in a general sense to include all penetrating high-frequency radiations and neutrons that caused injury—are well established, even though the Allies had no observers in the affected areas for several weeks after the explosions.

Our understanding of radiation casualties is not complete. In part the deficiency is in our basic knowledge of how radiation affects animal tissue. In the words of Dr. Robert Stone of the Manhattan Project, ‘The fundamental mechanism of the action of radiation on living tissues has not been understood.…”

According to the Japanese, those individuals very near the center of the explosion but not affected by flash burns or secondary injuries became ill within 2 or 3 days. Bloody diarrhea followed, and the victims expired, some within 2 to 3 days after the onset and the majority within a week. Autopsies showed remarkable changes in the blood picture—almost complete absence of white blood cells, and deterioration of bone marrow. Mucous membranes of the throat, lungs, stomach, and the intestines showed acute inflammation.

The majority of the radiation cases, who were at greater distances, did not show severe symptoms until 1 to 4 weeks after the explosion, though many felt weak and listless on the following day. After a day or two of mild nausea and vomiting, the appetite improved and the person felt quite well until symptoms reappeared at a later date.… Within 12 to 48 hours, fever became evident. In many instances it reached only 100° Fahrenheit and remained for only a few days. In other cases, the temperature went as high as 104° or 106° Fahrenheit. The degree of fever apparently had a direct relation to the degree of exposure to radiation. Once developed, the fever was usually well sustained, and in those cases terminating fatally it continued high until the end. If the fever subsided, the patient usually showed a rapid disappearance of other symptoms and soon regained his feeling of good health. The other symptoms commonly seen were shortage of white corpuscles, loss of hair, inflammation and gangrene of the gums, inflammation of the mouth and pharynx, ulceration of the lower gastro-intestinal tract, small livid spots (petechiae) resulting from escape of blood into the tissues of the skin or mucous membrane, and larger hemorrhages of gums, nose and skin.…

A decrease in the number of white blood corpuscles in the circulating blood appears to have been a constant accompaniment of radiation disease, even existing in some milder cases without other radiation effects. The degree of leukopenia was probably the most accurate index of the amount of radiation a person received. The normal white blood count averages 5,000 to 7,000: leukopenia is indicated by a count of 4,000 or less. The white blood count in the more severe cases ranged from 1,500 to 0, with almost entire disappearance of the bone marrow. The moderately severe cases showed evidence of degeneration of bone marrow and total white blood counts of 1,500 to 3,000. The milder cases showed white blood counts of 3,000 to 4,000 with more minor degeneration changes in the bone marrow. The changes in the system for forming red blood corpuscles developed later, but were equally severe.

Radiation clearly affected reproduction, though the extent has not been determined. Sterility has been a common finding throughout Japan, especially under the conditions of the last 2 years, but there are signs of an increase in the Hiroshima and Nagasaki areas to be attributed to the radiation. Sperm counts done in Hiroshima under American supervision revealed low sperm counts or complete aspermia for as long as 3 months afterward in males who were within 5,000 feet of the center of the explosion. Cases dying of radiation disease showed clear effects on spermatogenesis. Study of sections of ovaries from autopsied radiation victims has not yet been completed. The effects of the bomb on pregnant women are marked, however. Of women in various stages of pregnancy who were within 3,000 feet of ground zero, all known cases have had miscarriages. Even up to 6,500 feet they have had miscarriages or premature infants who died shortly after birth. In the group between 6,500 and 10,000 feet, about one-third have given birth to apparently normal children. Two months after the explosion, the city’s total incidence of miscarriages, abortions, and premature births was 27 percent as compared with a normal rate of 6 percent. Since other factors than radiation contributed to this increased rate, a period of years will be required to learn the ultimate effects of mass radiation upon reproduction.…

Unfortunately, no exact definition of the killing power of radiation can yet be given, nor a satisfactory account of the sort and thickness of concrete or earth that will shield people.… In the meanwhile the awesome lethal effects of the atomic bomb and the insidious additional peril of the gamma rays speak for themselves.

There is reason to believe that if the effects of blast and fire had been entirely absent from the bombing, the number of deaths among people within a radius of one-half mile from ground zero would have been almost as great as the actual figures and the deaths among those within 1 mile would have been only slightly less. The principal difference would have been in the time of the deaths. Instead of being killed outright as were most of these victims, they would have survived for a few days or even 3 or 4 weeks, only to die eventually of radiation disease.…

The General Effects of the Atomic Bombs impacted negatively on the environment as Radiation disease spread across the country.

Source: Articles from Bibliobase edited by Michael A. Bellesiles. Copyright © 1998 by Houghton Mifflin Company.

Absorption of Electromagnetic Radiation

The absorption of electromagnetic radiation can be explained by considering transverse waves. Electromagnetic radiation is the transfer of energy by waves travelling at the speed of light (300,000km/s) in a vacuum. These waves are transverse waves and have both and electric and a magnetic component to them. There is a spectrum of electromagnetic radiation from high energy waves (short wave lengths) such as gamma rays and x-rays, through ultraviolet, visible light and infra-red radiation to lower energy waves such as microwaves and radio waves (long wavelengths).

Radiation may be absorbed by many types of materials. It turns out that all objects are able to emit radiation at all wavelengths and similarly absorb all types of radiation. In fact good emitters are also good absorbers of radiation. However, the intensity of the radiation emitted or absorbed will vary enormously with different wavelengths of radiation.

Dark colored objects tend to absorb the thermal energy from radiation more efficiently than light colored or white objects. Light colored materials are more likely to reflect the radiation away from them. The rate of absorption of radiation depends strongly on the temperature difference between the absorbing material and the emitter of the radiation. In fact it varies with the fourth power of T, where T is the temperature difference (T4). The rate of absorption is also dependent on the amount of exposed surface area – the larger the area, the greater the absorption.

As radiation is absorbed, its energy is transferred to the materials constituent atoms and molecules. This energy transfer depends on the wavelength or energy of the incoming radiation. Microwave radiation, for example, will be absorbed in such a way that the bonds between molecules in the material will vibrate and the temperature of the body will rise. Some of the energy, however, may be re-emitted. For example when a poker is placed in a fire, it absorbs infrared radiation and stores part of it as heat and re-emits part as light as it glows. In conclusion, the absorption of electromagnetic radiation would depend on the type of material used and its intensity on the wavelength of radiation.