Nuclear power, as with all power sources, has an effect on the environment through the
nuclear fuel cycle, through operation, and (in Europe) from the lingering effects of the
Chernobyl accident.
Radioactive contamination is the uncontrolled distribution of radioactive material in a
given environment. The amount of radioactive material released in an accident is called
the source term.
High level waste
Around 300 tonnes of high-level waste is produced per month per nuclear reactor.[12]
Currently most spent nuclear fuel outside the U.S. is reprocessed for the useful
components, leaving only a much smaller volume of short half-life waste to be stored.
Several methods have been suggested for final disposal of high-level waste, including
deep burial in stable geological structures, transmutation, and removal to space.
Currently, monitored retrieveable storage is the option being most prepared.
Some nuclear reactors, such as the Integral Fast Reactor, have been proposed that use a
different nuclear fuel cycle that avoids producing waste containing long-lived radioactive
isotopes or actually burns those isotopes from other plants.
Radioactive contamination is typically the result of a spill or accident during the
production or use of radionuclides (radioisotopes), an unstable nucleus which has
excessive energy. Contamination may occur from radioactive gases, liquids or particles.
For example, if a radionuclide used in nuclear medicine is accidentally spilled, the
material could be spread by people as they walk around. Radioactive contamination may
also be an inevitable result of certain processes, such as the release of radioactive xenon
in nuclear fuel reprocessing. In cases that radioactive material cannot be contained, it
may be diluted to safe concentrations. Nuclear fallout is the distribution of radioactive
contamination by a nuclear explosion.
Nuclear energy poses a threat to not only the enviornment, but to human health and life
as well from the dangers of uranium mining, the power plants themselves, transportation,
and storage of waste. Each step in nuclear power poses great risks for human beings.
Probable Health Effects resulting from Exposure to Ionising Radiation
Dose in rems Health effects
(whole body) Immediate Delayed
1,000 or more Immediate death. None
`Frying of the brain'.
600-1,000 Weakness, nausea, Death in about 10 days.
vomiting and diarrhoea Autopsy shows
followed by apparent destruction of
improvement. After hematopoietic tissues,
several days: fever, including bone marrow,
diarrhoea, blood lymph nodes and spleen;
discharge from the swelling and
bowels, haemorrhage of degeneration of
the larynx, trachea, epithelial cells of the
bronchi or lungs, intestines, genital organs
vomiting of blood and and endocrine glands.
blood in the urine.
250-600 Nausea, vomiting, Radiation-induced
diarrhoea, epilation (loss atrophy of the endocrine
of hair), weakness, glands including the
malaise, vomiting of pituitary, thyroid and
blood, bloody discharge adrenal glands.
from the bowels or From the third to fifth
kidneys, nose bleeding, week after exposure,
bleeding from gums and death is closely
genitals, subcutaneous correlated with degree
bleeding, fever, of leukocytopenia. More
inflammation of the than 50% die in this
pharynx and stomach, time period.
and menstrual Survivors experience
abnormalities. Marked keloids,
destruction of bone ophthalmological
marrow, lymph nodes disorders, blood
and spleen causes dyscrasis, malignant
decrease in blood cells tumours, and
especially granulocytes psychoneurological
and thrombocytes. disturbances.
150-250 Nausea and vomiting on Symptoms of malaise as
the first day. Diarrhoea indicated above. Persons
and probable skin burns. in poor health prior to
Apparent improvement exposure, or those who
for about two weeks develop a serious
thereafter. Foetal or infection, may not
embryonic death if survive.
pregnant. The healthy adult
recovers to somewhat
normal health in about
three months. He or she
may have permanent
health damage, may
develop cancer or
benign tumours, and will
probably have a
shortened lifespan.
Genetic and teratogenic
effects.
50-150 Acute radiation sickness Tissue damage effects
and burns are less are less severe.
severe than at the higher Reduction in
exposure dose. lymphocytes and
Spontaneous abortion or neutrophils leaves the
stillbirth. individual temporarily
very vulnerable to
infection. There may be
genetic damage to
offspring, benign or
malignant tumours,
premature ageing and
shortened lifespan.
Genetic and teratogenic
effects.
10-50 Most persons Transient effects in
experience little or no lymphocytes and
immediate reaction. neutrophils. Premature
Sensitive individuals ageing, genetic effects
may experience and some risk of
radiation sickness. tumours.
0-10 None Premature ageing, mild
mutations in offspring,
some risk of excess
tumours. Genetic and
teratogenic effects.
The Fissioning Process and its Consequences
In order to understand nuclear technology and its impact on human health, three atomic-
level events must be understood: fissioning, activation and ionisation. Fissioning, i.e. the
splitting of the uranium or plutonium atom, is responsible for producing radioactive
fission fragments and activation products. These in turn cause the ionisation of normal
atoms, leading to a chain of microscopic events we may eventually observe as a cancer
death or a deformed child.
The atomic structure of fission fragments is unstable. The atom will at some time release
the destabilizing particle and return to a natural, low-energy, more stable form. Every
such release of energy is an explosion on the microscopic level. With each fissioning, 2
or 3 neutrons are released which can strike a nearby U235 atom causing more fissioning
in what is usually called a chain reaction.
Within the Living Cell
The chaotic state induced within a living cell when it is exposed to ionising radiation has
been graphically described by Dr Karl Z. Morgan as a `madman loose in a library'. [4] The
result of cell exposure to these microscopic explosions with the resultant sudden influx of
random energy and ionisation may be either cell death or cell alteration. The change or
alteration can be temporary or permanent. It can leave the cell unable to reproduce (or
replace) itself.
Radiation and Heredity
In 1943, Hermann Müller received a Nobel Prize for his work on the genetic effects of
radiation and was a dominant figure in developing early radiation exposure
recommendations made by the International Commission on Radiological Protection
(ICRP).[16] He showed through his work with Drosophila, a fruit fly, that ionising
radiation affects not only the biological organism which is exposed but also the seed
within the body from which the future generations are formed.
In 1964 Hermann Müller published a paper, `Radiation and Heredity', spelling out
clearly the implications of his research for genetic effects (damage to offspring) of
ionising radiation on the human species.[17] The paper, though accepted in
medical/biological circles, appears not to have affected policy makers in the political or
military circles who normally undertake their own critiques of published research. Müller
predicted the gradual reduction of the survival ability of the human species as several
generations were damaged through exposure to ionising radiation. This problem of
genetic damage continues to be mentioned in official radiation-health documents under
the heading `mild mutations'[18] but these mutations are not `counted' as health effects
when standards are set or predictions of health effects of exposure to radiation are made.
There is a difficulty in distinguishing mutations caused artificially by radiation from
nuclear activities from those which occur naturally from earth or cosmic radiation. A
mild mutation may express itself in humans as an allergy, asthma, juvenile diabetes,
hypertension, arthritis, high blood cholesterol level, slight muscular or bone defects, or
other genetic `mistakes'. These defects in genetic make-up leave the individual slightly
less able to cope with ordinary stresses and hazards in the environment. Increasing the
number of such genetic `mistakes' in a family line, each passed on to the next generation,
while at the same time increasing the stresses and hazards in the environment, leads to
termination of the family line through eventual infertility and/or death prior to
reproductive age. On a large scale, such a process leads to selective genocide of families
or species suicide.[19]
It soon became obvious that the usual method determining a tolerance level for
human exposure to toxic substances was inappropriate for ionising radiation. The health
effects were similar to normally occurring health problems and were quite varied, ranging
from mild to severe in a number of different human organ systems, and their appearance
could be delayed for years or even generations.
A study has been done in the USA on the chemical form of uranium in soil, this was
published by Benjamin C. Bostick, Scott Fendorf, Mark O. Barnett, Phillip M. Jardine
and Scott C. Brooks in Soil Science Society of America Journal 66:99-108 (2002) [10].
It has been suggested that it is possible to form a reactive barrier by adding something to
the soil which will cause the uranium to become fixed. One method of doing this is to use
a mineral (apatite) [11] while a second method is to add a food substance such as acetate
to the soil. This will enable bacteria to reduce the uranium (VI) to uranium (IV) which is
much less soluble.
In peat like soils the uranium will tend to bind to the humic acids, this tends to fix the
uranium in the soil.[12] A report on the binding of uranium, other radioactive metals and
non radioactive metal to humic acid has been published by the INE (German nuclear
engineering research center) at FZK (Karlsruhe) has been published.[13] also see the
paper by S. Pompe, K. Schmeide, M. Bubner, G. Geipel, K.-H. Heise, G. Bernhard and
H. Nitsche in Radiochimica Acta, 2000, 88, 553-558 in which the effect of the phenol
groups in the humic acid upon the binding of the uranium are studied. A series of papers
have been written on coordination polymers or uranium(VI) with polycarboxylates, these
have been used as models for the uranyl complexes of the humic acids.
For instance see G. Micera et al., Inorganica Chimica Acta, 1985, 109, 135-139 which is
a paper about the coordination of uranium to 2,6-dihydroxybenzoate which is a
carboxylic acid which has phenolic groups close to the carboxylic acid group.
2,6-dihydroxybenzoic acid
Some other work on the binding of actinides with aromatic carboxylates has been
reported. A paper on the binding of neptunium(V) {neptunyl} with benzene-1,2,4,5-
tetracarboxylic acid has been reported by F. Nectoux et al., Journal of the Less-Common
Metals, 1984, 97, 1-10.
Benzene-1,2,4,5-tetracarboxylic acid
A PhD thesis on the interactions of uranium with Boom Clay has been published.[14]
It is interesting to note that A. Rossberg, L. Baraniak, T. Reich, C. Hennig, G. Bernhard
and H. Nitsche, Radiochimica Acta, 2000, 88, 593-597 describes an EXAFS study of the
interactions of uranium with the degradation products of wood such as protocatechuic
acid (3,4-dihydroxy-benzoic acid), catechol (2-hydroxyphenol), pyrogallol (1,2,3-
trihydroxybenzol), and vanillic acid (4-hydroxy-3-methoxybenzoic acid).
Animals
It has been reported that uranium has caused reproductive effects, and other health
problems in rodents, frogs and other animals.
Uranium was shown to have cytotoxic, genotoxic and carcinogenic effects in animal
studies (PMID 7694141, PMID 16283518). It has been shown in rodents and frogs that
water soluble forms of uranium are teratogenic (PMID 16124873, PMID 11738513,
PMID 12539863)
[edit] Bacterial biochemistry
It has been shown in some recent work at Manchester that bacteria can reduce and fix
uranium in soils.[35] These bacterium change soluble U(VI) into the highly insoluble
complex forming U(IV) ion, hence stopping chemical leaching.
Prevention
See also: Radiation protection.
The best prevention for radiation sickness is to minimize the dose suffered by the human,
or to reduce the dose rate.
[edit] Distance
Increasing distance from the radiation source reduces the dose due to the inverse-square
law for a point source. Distance can be increased by means as simple as handling a
source with forceps rather than fingers.
[edit] Time
The longer that humans are subjected to radiation the larger the dose will be. The advice
in the nuclear war manual entitled "Nuclear War Survival Skills" published by Cresson
Kearny in the U.S. was that if one needed to leave the shelter then this should be done as
rapidly as possible to minimize exposure.
In chapter 12 he states that "Quickly putting or dumping wastes outside is not hazardous
once fallout is no longer being deposited. For example, assume the shelter is in an area
of heavy fallout and the dose rate outside is 400 R/hr enough to give a potentially fatal
dose in about an hour to a person exposed in the open. If a person needs to be exposed
for only 10 seconds to dump a bucket, in this 1/360th of an hour he will receive a dose of
only about 1 R. Under war conditions, an additional 1-R dose is of little concern."
In peacetime, radiation workers are taught to work as quickly as possible when
performing a task which exposes them to irradiation. For instance, the recovery of a lost
radiography source should be done as quickly as possible.
[edit] Shielding
By placing a layer of a material which will absorb the radiation between the source and
the human, the dose and dose rate can be reduced. For instance, in the event of a nuclear
war, it would be a good idea to shelter within a building with thick stone walls (Fallout
shelter). During the height of the cold war, fallout shelters were identified in many urban
areas. It is interesting to note that, under some conditions, shielding can increase the dose
rate. For instance, if the electrons from a high energy beta source (such as 32P) strike a
lead surface, X-ray photons will be generated (radiation produced in this way is known as
bremsstrahlung). It is best for this reason to cover any high Z materials (such as lead or
tungsten) with a low Z material such as aluminium, wood, plastic. This effect can be
significant if a person wearing lead-containing gloves picks up a strong beta source. Also,
gamma photons can induce the emission of electrons from very dense materials by the
photoelectric effect; again, by covering the high Z material with a low Z material, this
potential additional source of exposure to humans can be avoided. Furthermore, gamma
rays can scatter off a dense object; this enables gamma rays to "go around corners" to a
small degree. Hence, to obtain a very high protection factor, the path in/out of the
shielded enclosure should have several 90 degree turns rather than just one.
[edit] Reduction of incorporation into the human body
Potassium iodide (KI), administered orally immediately after exposure, may be used to
protect the thyroid from ingested radioactive iodine in the event of an accident or terrorist
attack at a nuclear power plant, or the detonation of a nuclear explosive. KI would not be
effective against a dirty bomb unless the bomb happened to contain radioactive iodine,
and even then it would only help to prevent thyroid cancer.
[edit] Fractionation of dose
While Devair Alves Ferreira received a large dose during the Goiânia accident of 7.0 Gy,
he lived while his wife received a dose of 5.7 Gy and died. The most likely explanation is
that his dose was fractionated into many smaller doses which were absorbed over a length
of time, while his wife stayed in the house more and was subjected to continuous
irradiation without a break, giving her body less time to repair some of the damage done
by the radiation. In the same way, some of the people who worked in the basement of the
wrecked Chernobyl plant received doses of 10 Gy, but in small fractions, so the acute
effects were avoided.
It has been found in radiation biology experiments that if a group of cells are irradiated,
then as the dose increases, the number of cells which survive decreases. It has also been
found that if a population of cells is given a dose before being set aside (without being
irradiated) for a length of time before being irradiated again, then the radiation causes
less cell death. The human body contains many types of cells and the human can be killed
by the loss of a single type of cells in a vital organ. For many short term radiation deaths
(3 days to 30 days), the loss of cells forming blood cells (bone marrow) and the cells in
the digestive system (microvilli which form part of the wall of the intestines are
constantly being regenerated in a healthy human) causes death.
In the graph below, dose/survival curves for a hypothetical group of cells have been
drawn, with and without a rest time for the cells to recover. Other than the recovery time
partway through the irradiation, the cells would have been treated identic
Treatment
Treatment reversing the effects of irradiation is currently not possible. Anaesthetics and
antiemetics are administered to counter the symptoms of exposure, as well as antibiotics
for countering secondary infections due to the resulting immune system deficiency.
There are also a number of substances used to mitigate the prolonged effects of radiation
poisoning, by eliminating the remaining radioactive materials, post exposure.
PROTECTING LIVESTOCK
How will fallout affect unprotected livestock, that is, animals in
fields, postures, and other open areas?
Fallout may be dangerous to cattle, sheep, horses, pigs, and
other livestock as well as to human beings. Radioactive
materials in fresh fallout can contaminate the immediate
environment and give off rays that can penetrate deep into the
body. This is the major source of danger for livestock. Animals
can also suffer skin burns if fallout settles in the coat. Skin
burns could produce considerable discomfort, but would not
endanger the lives of the animals.
Animals are about as sensitive to radiation damage as human
beings; to survive, animals need the same protection as human
beings.
When livestock must graze on fallout-contaminated pasture,
supplemental feeding from non-contaminated forage can
materially reduce the daily dose of radioactive material the
animals will eat. Stored or stacked hay, ensilage from either
silo or trench, and stored grain are safe supplemental feeds
when they are protected from fallout contamination. When no
shelter is available and when the level of radiation is only
moderate, or food resources are scant, growers should, if
possible, supply supplemental feeding and limit the grazing
time.
When meat and dairy animals eat contaminated feed, some
radioactive elements are absorbed into their bodies. Thus,
man's food supply of animal products can become
contaminated with radioactivity.
How will fallout affect sheltered livestock?
Livestock housed in barns and other farm buildings during
fallout have a better chance of surviving effects of radiation
than those that are not sheltered. A reasonably well-built
shelter reduces intensity of external radiation and prevents
fallout from settling on the animals' bodies. It also prevents
animals from eating contaminated feed.
What Is the best way to protect livestock from fallout?
Move them indoors as soon as possible. If you do not have
adequate facilities to house all animals, put some of them near
farm buildings or in a small dry lot. Under these conditions the
amount of space per animal in a barn should be reduced to the
point of overcrowding. The limiting factor is ventilation and not
space. The advantage is that the animals tend to shield each
other enough that more will survive under crowded conditions
than under normal housing. Large, protected self-feeders and
automatic live- stock waterers can supply uncontaminated feed
and water.
Areas within movable fences, and other small fenced areas that
have covered feeders or self-feeders, can provide emergency
confinement for farm animals after early external radiation
intensity has decreased through decay.
Empty trench silos can be converted to livestock shelters by
constructing a roof over the trench and covering it with earth.
Once fallout occurs, you should not attempt to protect livestock
unless local civil defense authorities tell you that you will he
safe when doing so.
Get your dairy cattle under cover first
What water can I give livestock after fallout?
Water from a covered well, tank, or cistern, or from a freely
running spring, is best. River water or pond water is less safe,
but if necessary, it could be used after fallout has occurred. In
a few days it would be safe. If, however, it should rain during
this time, livestock should not be permitted access to pond
water for an additional few days.
Usually, fallout particles would settle promptly and soluble
radioactive materials would diffuse in the water, reducing the
contamination at the surface. If the water was constantly
replenished from an uncontaminated source, radioactivity
would be diluted rapidly.
To prevent contamination from fallout, do not add water to
covered tanks unless the water is from a protected well or
spring; first use the water originally present in the tanks.
Could I use water in an exposed pond?
Water in an exposed pond would be contaminated, but usually
the level of contamination would decrease rapidly. Such water
could be used for surface irrigation. It could also he used to
wash off farm buildings and unsheltered livestock. Obtain
drinking water for livestock from another source if possible.
What feed can I give livestock after fallout?
To protect feed adequately, cover it. Fallout is like dust or dirt;
a cover will prevent it from coming in contact or mixing with
the feed.
Grain stored in a permanent bin, hay in a barn, and ensilage in
a covered silo are adequately protected. They can be used as
soon as it is safe to get to them following fallout.
A haystack in an open field can be protected with a tarpaulin or
similar covering.
If possible, give your livestock feed that does not contain
fallout material. Fallout particles that settle on hay, silage, or a
stack of feedbags will contaminate only the outer parts. You
can remove the outer layers or bags, and use the inside feed
that is unaffected.
You will be notified if local civil defense and agricultural
authorities who measure concentrations of fallout consider the
forage growing in your area is harmful. However, this advice
might come too late in heavily contaminated areas. As a
precautionary measure, house the livestock and do not let them
graze.
You may have to give cows contaminated feed if no other feed
is available. The milk from these cows should not be used by
children, but when the cows are back on clean feed, the
amount of radioactive material in their milk will progressively
diminish.
What can I do with contaminated feed?
How long feed should be stored depends on the type and
concentration of the radioactive materials. If you have an
alternate supply, do not use contaminated feed until told by
authorities that it is safe to do so; then be sure to follow the
precautions they may recommend.
Should dairy cows receive special treatment?
Yes. Because radioactive materials can be transferred to milk,
which will be a critical product during an emergency, make a
special effort to protect cows from fallout. Remove milking
cows from pasture and feed them stored rations during the
period of fresh fallout and for several weeks after. In this way,
you will prevent iodine 131 from occurring in the milk, or
reduce it to insignificant levels.
Give cows preferred shelter and clean feed and water. If you
can, milk them before fallout occurs; you may not be able to do
so for several days afterward. If you have calves on the farm
turn them in with the cows. This will help prevent mastitis and
conserve all the feed for the cows. Reduce amounts of water
and concentrated feed to maintenance levels.
Construction plans are available through State extension
agricultural engineers for a combination dairy barn and family
fallout shelter. Although construction of this type is costly,
such a facility might be considered for the protection of highly
valued breeding stock.
The plans are designed in accordance with milk production
ordinances. They provide for (1) a year-round production Unit
that requires minimum change for emergency use, (2) a built-
in family fallout protection area that allows the operator to
care for animals during a fallout emergency, (3) all stored feed
that is manually accessible to be inside the barn, (4) stored hay
and straw for use as shielding, (5) temporary housing, feed,
and water for other livestock, (6) an auxiliary generator for
assuring electric power, and (7) a water supply inside the barn.
What measures should be taken to protect poultry?
Measures for protecting poultry are the same as those
recommended for other farm animals.
Poultry are somewhat more resistant to radiation than other
farm animals. Since most poultry are raised under shelter and
given feed that has been protected or stored, and since poultry
can be grown rapidly, they are one of the more dependable
sources of fresh foods of animal origin that may be available
following a nuclear attack.
Hens that eat contaminated feed will produce eggs that contain
some radioactive elements. Radioactivity in eggs decreases
shortly after the hens are removed from the contaminated
environment and given uncontaminated feed and water.
What animal food products are safe to market after fallout?
You will receive specific instructions from local civil defense
authorities based on the amount of fallout received. Do not
destroy any animal food products unless spoilage has made
them inedible. Milk should be safe to use if it is from cows that
are adequately sheltered and protected and are fed rations of
stored and protected feed and water. Milk from a fallout area
where cows are not adequately protected or fed stored feed
should not be given to children until civil defense authorities
approve. Milk contaminated with iodine 131 can be processed
into butter, cheese, and powdered or canned milk, and stored
for a period of time to allow the radioactivity to decay.
Food animals whose bodies have been exposed to external
radiation can be used for food if they are slaughtered before
the onset of signs of radiation sickness. Also, they can be used
after they have recovered from the ensuing illness. The same
rules that govern the slaughter of animals sick from any cause
should be followed. Care must be taken to prevent edible parts
of the carcass from being contaminated by radioactive
materials contained on the hide and in the digestive system.
What do I do if animals die from fallout radiation?
Some of your animals may be affected so severely by radiation
from fresh fallout that they will die in a few days or weeks after
being exposed. Do not slaughter any of your livestock unless
you are told to do so by local civil defense authorities or USDA
county defense boards. Bury animals that die. These carcasses
usually are not dangerous to surviving people or animals by the
time it is safe to work outside.
Is it possible to decontaminate livestock and farm buildings
that have been exposed to fallout?
If there is fallout on the animals’ skins, the radioactive material
can be washed off with water. It is not necessary to use clean
water sources for this purpose. Take care to avoid
contamination runoff.
Civil defense authorities or USDA county defense boards may
advise you on decontamination procedures for your farm
buildings. In handling animals, wear coveralls, gloves, and
boots to prevent contaminating yourself. Cleaning or
disinfecting buildings will not destroy radioactivity. However,
cleaning can be useful in moving radioactive materials to a
place where radiation will be less harmful. In cleaning, be
careful to avoid contaminating yourelf.
PROTECTING LAND AND CROPS
What are the main consequences of heavy concentration of
fallout on crop and pasture lands?
! Farm workers may not be able to manage and cultivate land
safely for some time, because of radiation hazard.
! It may not be advisable to permit animals to graze, because
of the danger of radiation.
! Fresh fallout would provide surface contamination on all
plants, resulting in potential hazard to human beings and
animals consuming them.
! Radiation from fallout deposited on the leaves or the ground
may damage the crop.
How long would fallout affect cultivated and non-cultivated
lands?
It would depend on the abundance and type of radioactive
materials in a given area. In the event of nuclear attack,
radioactive iodine would be the most critical single factor in the
contamination of milk during the first few weeks. After the first
60 days, the principal hazard would arise from strontium 89
and strontium 90. Strontium 89, however, will have virtually
disappeared 17 months after its formation.
Like other radioactive isotopes of fallout, strontium 90 falls on
the surface of plants and can be consumed with foods and
forage. Some of it is deposited directly on the soil or washed
into it, remaining indefinitely, for all practical purposes, in the
top several inches of uncultivated land. Because it is chemically
similar to calcium, radioactive strontium would be absorbed by
all plants. Plants growing in soils deficient in calcium would
absorb more radioactive strontium than those growing in soils
abundant in calcium, other conditions being equal.
Are there soil treatments for reducing the fallout hazard on
land?
Yes, but soil treatments should be given only after responsible
authorities have carefully evaluated the situation and declared
a state of emergency. The most effective treatment could be
costly, and suitable only for intensively used land.
Other methods involve changes in generally accepted farm
practices. Some measures could be simply an improvement
over local conditions and procedures. For example, liming of
acid soils could reduce the uptake of radioactive strontium in
crops grown on those soils.
USDA soil scientists in the USDA county defense boards will
provide guidance to farmers in determining best utilization of
their land following nuclear attack.
Any use of the land must wait until external radiation levels are
low enough for persons to work safely outdoors.
Would fallout permanently affect pasture grass and forage
crops?
If fallout is extremely light, the pasture would be usable
immediately. It is difficult to set an exact external dose rate at
which it would be safe to return the animals to pasture, but if
the dose for the first week of stay did not exceed 25 roentgens
all animals would survive and could be handled with safety.
If fallout is heavy, external radiation would prohibit use of the
pasture. A heavy deposit of fallout would spread short-lived
and long-lived radioactive particles on the pasture and forage
crops. Radiation might cause visible injury to plants. Some
plants might die.
Existing growths of alfalfa and other forage crops might not be
usable because of radiation hazard. If a radiation survey should
indicate that contamination level is high, existing growth
should be removed as close to the ground as possible and
discarded; succeeding growths should be used only after
examination for radioactivity. If the soil is acid, a top-dressing
of lime would help reduce uptake of radioactive strontium in
succeeding growths.
Livestock could be allowed to graze on lightly contaminated
pasture after a waiting period that varies from one to a few
weeks, the length of time depending on the degree of
contamination.
Once it is safe to work the land, a periodic check on pasture
and produce in affected areas would provide the best safety
guide to their use.
Would fallout affect my system of farming?
It could. Seriously contaminated land may need to lie fallow for
as long as a season. After this, fallout may require a change to
non-food crops or to food crops that do not absorb large
amounts of radioactive materials from the soil. Alfalfa, clover,
soybeans, and leafy vegetables have a greater tendency to
absorb long-lived radioactive strontium than cereal grains,
grasses, corn, potatoes, and fruits. Guidance on suggested
crops to plant will come from USDA county defense boards.
Would fallout reduce economic productivity of crop and pasture
lands?
Fallout might reduce such productivity in several ways: (1)
Crop and soil management could be impeded because of danger
from external radiation; (2) some crops might be killed by
contamination; (3) other crops might become contaminated to
a degree where they would be unmarketable; and (4) economic
value of food grown on contaminated land might be less than
that of other competitive crops.
What are the effects of fallout on growing vegetables?
Growing vegetables that are exposed to heavy fallout may
become highly contaminated. Leaves, pods, and fruits that
retain fallout material should be cleaned before being eaten.
Washing is probably the most effective measure, just as it is
the best way to clean garden foods that get dirty from any
other cause. Radiation from heavy fallout may affect plant
growth. Roots and tubers absorb little contamination from
fallout before it is mixed with the soil. The normal cleaning or
peeling of underground vegetables such as potatoes or carrots
would be adequate for removing fallout.
What are the effects of fallout on fruits?
If fallout is heavy, ripe fruits may be lost because of the
personal hazard involved in harvesting them. Fruits that do not
have to be picked immediately can be saved. They should be
washed before they are eaten.
Would fallout limit use of plants for human food?
It depends on the extent of radioactivity. Leafy vegetables,
such as lettuce, should not be eaten unless they are thoroughly
washed, or are known to be free of hazardous amounts of
radioactive materials.
What special precautions should be taken for workers in the
fields?
You should remain indoors until danger from fallout has
diminished and you have learned from local officials that it is
all right to work outdoors.
http://www.ratical.org/radiation/NRBE/index.html
http://en.wikipedia.org/wiki/Environmental_effects_of_nuclear_power
http://www.colby.edu/personal/c/clresseg/STS_files/envir.html
http://www.radshelters4u.com/index3.htm
