Effects of Nuclear Weapons, Part II



Radiation Effects on Humans

Certain body parts are more specifically affected by exposure to different types of radiation sources. Several factors are involved in determining the potential health effects of exposure to radiation. These include:

The size of the dose (amount of energy deposited in the body)
The ability of the radiation to harm human tissue
Which organs are affected
The most important factor is the amount of the dose – the amount of energy actually deposited in your body. The more energy absorbed by cells, the greater the biological damage. Health physicists refer to the amount of energy absorbed by the body as the radiation dose. The absorbed dose, the amount of energy absorbed per gram of body tissue, is usually measured in units called rads. Another unit of radation is the rem, or roentgen equivalent in man. To convert rads to rems, the number of rads is multiplied by a number that reflects the potential for damage caused by a type of radiation. For beta, gamma and X-ray radiation, this number is generally one. For some neutrons, protons, or alpha particles, the number is twenty.

Hair

The losing of hair quickly and in clumps occurs with radiation exposure at 200 rems or higher.

Brain

Since brain cells do not reproduce, they won’t be damaged directly unless the exposure is 5,000 rems or greater. Like the heart, radiation kills nerve cells and small blood vessels, and can cause seizures and immediate death.

Thyroid

The certain body parts are more specifically affected by exposure to different types of radiation sources. The thyroid gland is susceptible to radioactive iodine. In sufficient amounts, radioactive iodine can destroy all or part of the thyroid. By taking potassium iodide can reduce the effects of exposure.

Blood System

When a person is exposed to around 100 rems, the blood’s lymphocyte cell count will be reduced, leaving the victim more susceptible to infection. This is often refered to as mild radiation sickness. Early symptoms of radiation sickness mimic those of flu and may go unnoticed unless a blood count is done.According to data from Hiroshima and Nagaski, show that symptoms may persist for up to 10 years and may also have an increased long-term risk for leukemia and lymphoma. For more information, visit Radiation Effects Research Foundation.

Heart

Intense exposure to radioactive material at 1,000 to 5,000 rems would do immediate damage to small blood vessels and probably cause heart failure and death directly.

Gastrointestinal Tract

Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This is occurs when the victim’s exposure is 200 rems or more. The radiation will begin to destroy the cells in the body that divide rapidly. These including blood, GI tract, reproductive and hair cells, and harms their DNA and RNA of surviving cells.

Reproductive Tract

Because reproductive tract cells divide rapidly, these areas of the body can be damaged at rem levels as low as 200. Long-term, some radiation sickness victims will become sterile.

Dose-rem Effects
5-20 Possible late effects; possible chromosomal damage.
20-100 Temporary reduction in white blood cells.
100-200 Mild radiation sickness within a few hours: vomiting, diarrhea, fatigue; reduction in resistance to infection.
200-300 Serious radiation sickness effects as in 100-200 rem and hemorrhage; exposure is a Lethal Dose to 10-35% of the population after 30 days (LD 10-35/30).
300-400 Serious radiation sickness; also marrow and intestine destruction; LD 50-70/30.
400-1000 Acute illness, early death; LD 60-95/30.
1000-5000 Acute illness, early death in days; LD 100/10.


Long Term Effects on Humans

Long after the acute effects of radiation have subsided, radiation damage continues to produce a wide range of physical problems. These effects- including leukemia, cancer, and many others- appear two, three, even ten years later.

Blood Disorders

According to Japanese data, there was an increase in anemia among persons exposed to the bomb. In some cases, the decrease in white and red blood cells lasted for up to ten years after the bombing.

Cataracts

There was an increase in cataract rate of the survivors at Hiroshima and Nagasaki, who were partly shielded and suffered partial hair loss.

Malignant Tumors

All ionizing radiation is carcinogenic, but some tumor types are more readily generated than others. A prevalent type is leukemia. The cancer incidence among survivors of Hiroshima and Nagasaki is significantly larger than that of the general population, and a significant correlation between exposure level and degree of incidence has been reported for thyroid cancer, breast cancer, lung cancer, and cancer of the salivary gland. Often a decade or more passes before radiation-caused malignancies appear.

Keloids

Beginning in early 1946, scar tissue covering apparently healed burns began to swell and grow abnormally. Mounds of raised and twisted flesh, called keloids, were found in 50 to 60 percent of those burned by direct exposure to the heat rays within 1.2 miles of the hypocenter. Keloids are believed to be related to the effects of radiation.


Radioactive Fallout

Fallout is the radioactive particles that fall to earth as a result of a nuclear explosion. It consists of weapon debris, fission products, and, in the case of a ground burst, radiated soil. Fallout particles vary in size from thousandths of a millimeter to several millimeters. Much of this material falls directly back down close to ground zero within several minutes after the explosion, but some travels high into the atmosphere. This material will be dispersed over the earth during the following hours, days (and) months. Fallout is defined as one of two types: early fallout, within the first 24 hours after an explosion, or delayed fallout, which occurs days or years later.

Most of the radiation hazard from nuclear bursts comes from short-lived radionuclides external to the body; these are generally confined to the locality downwind of the weapon burst point. This radiation hazard comes from radioactive fission fragments with half-lives of seconds to a few months, and from soil and other materials in the vicinity of the burst made radioactive by the intense neutron flux.

Most of the particles decay rapidly. Even so, beyond the blast radius of the exploding weapons there would be areas (hot spots) the survivors could not enter because of radioactive contamination from long-lived radioactive isotopes like strontium 90 or cesium 137. For the survivors of a nuclear war, this lingering radiation hazard could represent a grave threat for as long as 1 to 5 years after the attack.

Predictions of the amount and levels of the radioactive fallout are difficult because of several factors. These include; the yield and design of the weapon, the height of the explosion, the nature of the surface beneath the point of burst, and the meteorological conditions, such as wind direction and speed.

An air burst can produce minimal fallout if the fireball does not touch the ground. On the other hand, a nuclear explosion occurring at or near the earth’s surface can result in severe contamination by the radioactive fallout.


Fallout Particles

Many fallout particles are especially hazardous biologically. Some of the principal radioactive elements are as follows:

Strontium 90 is very long-lived with a half-life of 28 years. It is chemically similar to calcium, causing it to accumulate in growing bones. This radiation can cause tumors, leukemia, and other blood abnormalities.

Iodine 131 has a half-life of 8.1 days. Ingestion of it concentrates in the thyroid gland. The radiation can destroy all or part of the thyroid. Taking potassium iodide can reduce the effects.

The amount of tritium released varies by bomb design. It has a half-life of 12.3 years and can be easily ingested, since it can replace a hydrogen in water. The beta radiation can cause lung cancer.

Cesium 137 has a half-life of 30 years. It does not present as large a biological threat as Strontium 90. It behaves similar to potassium, and will distribute fairly uniformly thoughout the body. This can contribute to gonadal irradiation and genetic damage.

When a plutonium weapon is exploded, not all of the plutonium is fissioned. Plutonium 239 has a half-life of 24,400 years. Ingestion of as little as 1 microgram of plutonium, a barely visible speck, is a serious health hazard causing the formation of bone and lung tumors.

The details of the actual fallout pattern depend on wind speed and direction and on the terrain. The fallout will contain about 60 percent of the total radioactivity. The largest particles will fall within a short distance of ground zero. Smaller particles will require many hours to return to earth and may be carried hundreds of miles. This means that a surface burst can produce serious contamination far from the point of detonation.


This map shows the total dose contours from early fallout from a surface burst of a 1-megaton fission yield.



From the 15-megaton thermonuclear device tested at Bikini Atoll on March 1, 1954 – the BRAVO shot of Operation CASTLE – the fallout caused substantial contamination over an area of more than 7,000 square miles. The contaminated region was roughly cigar-shaped and extended more than 20 miles upwind and over 350 miles downwind.


Ozone Depletion

When a nuclear weapon explodes in the air, the surrounding air is subjected to great heat, followed by relatively rapid cooling. These conditions are ideal for the production of tremendous amounts of nitric oxides. These oxides are carried into the upper atmosphere, where they reduce the concentration of protective ozone. Ozone is necessary to block harmful ultraviolet radiation from reaching the Earth’s surface.


Oxides of nitrogen form a catalytic cycle to reduce the protective ozone layer.



The nitric oxides produced by the weapons could reduce the ozone levels in the Northern Hemisphere by as much as 30 to 70 percent. Such a depletion might produce changes in the Earth’s climate, and would allow more ultraviolet radiation from the sun through the atmosphere to the surface of the Earth, where it could produce dangerous burns and a variety of potentially dangerous ecological effects.

It has been estimated that as much as 5,000 tons of nitric oxide is produced for each megaton of nuclear explosive power.


Nuclear Winter

In 1983, R.P. Turco, O.B. Toon, T.P. Ackerman, J.B. Pollack, and Carl Sagan (referred to as TTAPS) published a paper entitled “Global Atmospheric Consequences of Nuclear War” which is the foundation on which the nuclear winter theory is based on.

Theory states that nuclear explosions will set off firestorms over many cities and forests within range. Great plumes of smoke, soot, and dust would be sent aloft from these fires, lifted by their own heating to high altitudes where they could drift for weeks before dropping back or being washed out of the atmosphere onto the ground. Several hundred million tons of this smoke and soot would be shepherded by strong west-to-east winds until they would form a uniform belt of particles encircling the Northern Hemisphere.

These thick black clouds could block out all but a fraction of the sun’s light for a period as long as several weeks. The conditions of semidarkness, killing frosts, and subfreezing temperatures, combined with high doses of radiation from nuclear fallout, would interrupt plant photosynthesis and could thus destroy much of the Earth’s vegetation and animal life. The extreme cold, high radiation levels, and the widespread destruction of industrial, medical, and transportation infrastructures along with food supplies and crops would trigger a massive death toll from starvation, exposure, and disease.

It is not certain that a nuclear war would produce a nuclear winter effect. However, it remains a possibility and the TTAPS study concluded: “…the possibility of the extinction of Homo Sapiens cannot be excluded.”


Source: http://www.atomicarchive.com/Effects/effects15.shtml

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One Response to “Effects of Nuclear Weapons, Part II”

  1. the extinction of Homo Sapiens is assured but unlikely from a nuclear war since the “winter effect” of all known nuclear weapons combined can not match the debris cloud of mother nature through fires, storms, and vulcanic eruptions in any given week.

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