Nuclear hazards
It is defined as the risk or danger to human health or the environment posed by radiation emanating from the atomic nuclei of a given substance or the possibility of an uncontrolled explosion originating from a fusion or fission reaction of atomic nuclear.
Sources of nuclear hazards:
The sources of radioactivity are both natural and manmade.
The natural sources include:
1) Cosmic rays from outer space:
The quantity depends on altitude and latitude. It is more at higher latitudes and high altitudes.
2) Emissions from radioactive materials from the Earth’s crust:
People have been exposed to low levels of radiation from these natural sources for several. But it is the manmade sources which are posing a threat to mankind. The man-made sources of radioactivity are nuclear wastes produced at the time of:
1) Uses of radioactive material in nuclear power plants.
2) Mining and processing of radioactive ores.
3) Uses of radioactive materials in nuclear weapons.
4) Uses of radioactive isotopes in medical, industrial and research applications.
The greatest exposure to human beings comes from the diagnostic use of the X-rays, radioactive isotopes used as the tracers and the treatment of cancer and other ailments.
Effects of nuclear hazards:
Effects of radioactive pollutants depend upon halflife, energy releasing capacity, rate of diffusion and rate of deposition of the contaminant. Various atmospheric conditions and climatic conditions such as temperature, wind and rainfall also determine their effect. All organisms are affected from radiation pollution and the effects are extremely dangerous. The effects may be somatic or genetic damage. The effects are cancer, shortening of life span and genetic effects or mutations. Some of the possible effects are listed as below.
1) Exposure at low doses of radiations (100-250 rads), men do not die but begin to suffer from fatigue, nausea, vomiting and loss of hair. But recovery can be possible.
2) Radiations may break the chemical bonds such as DNA in cells. This affects the genetic makeup and control mechanisms. The effects can be instantaneous, prolonged or delayed types. Even it could be carried to future generations.
3) Higher irradiation doses (10,000rads) kills the organisms by damaging the tissues of heart, brain, etc.
4) Exposure at higher doses (400-500 rads), blood cells are reduced, bone marrow is affected, blood fails to clot and the irradiated person soon dies of infection and bleeding.
5) Through food chain also, radioactivity effects are experienced by man. But the most significant effect of radioactivity causes long range effects, natural resistance and fighting capacity against germs is reduced, affecting the future of man and hence the future of our civilization.
6) Workers handling the radioactive wastes get slow but continuous irradiation and in course of time develop cancer of different types.
Control of nuclear hazards:
The peaceful uses of radioactive materials are so wide and effective that modern civilization cannot go without them on the other hand, there is no cure for radiation damage. Hence, the only option against nuclear hazards is to check and prevent radioactive pollution.
1) Safety measures are enforced strictly.
2) Leakages from nuclear reactors, careless handling, transport and use of radioactive fuels, fission products and radioactive isotopes have to be totally stopped.
3) There should be regular monitoring and quantitative analysis through frequent sampling in the risk areas.
4) Waste disposal is careful, efficient and effective.
5) Appropriate steps should be taken against occupational exposure.
6) Preventive measures should be followed so that background radiation levels do not exceed the permissible limits.
7) Safety measures should be strengthened against the nuclear accidents.
Disposal of nuclear wastes:
Since nuclear waste can be extremely dangerous and therefore, the way in which they are to be disposed of is strictly controlled by international agreement. Since 1983, by international agreement, the disposal in the Atlantic Ocean and into the atmosphere has been banned. After processing, to recover usable material and reducing the radioactivity of the waste, disposal is made in solid form where possible. The nuclear wastes are classified into three categories such as:
1) High Level Wastes (HLW):
High level wastes have a very high radioactivity per unit volume. For example, spent nuclear fuel. have to be cooled and are, therefore, stored for several decades by its producer before disposal. Since these wastes are too dangerous to be released anywhere in the biosphere, they must be contained either by converting them into inert solids and then buried deep into earth or are stored in deep salt mines.
2) Medium level wastes (MLW):
Medium level wastes are solidified and are mixed with concrete in steel drums before being buried in deep mines or below the sea bed in concrete chambers.
3) Low liquid wastes (LLW):
Low liquid wastes are disposed of in steel drums in concrete lined trenches in designated sites.
4.2 Role of an individual in prevention of pollution
Environmental pollution cannot be prevented and removed. The proper implementation and especially the individual participation are the important aspects which should be given due importance.
The individual participation is useful in law making processes and restraining the pollution activities and thereby the public participation plays a major role in the effective environmental management. A small effect is made by each individual at his own place will have pronounced effect at the global level. It is suitably said ‘Think globally act locally.’
Each individual should change his or her life style in a such a way as to reduce environmental pollution.
Individual Participation:
1) Help more in pollution prevention than pollution control.
2) Plant more trees.
3) Purchase recyclable, recycled and environmentally safe products.
4) Use water, energy and other resources efficiently.
5) Use natural gas than coal.
6) Use CFC free refrigerators.
7) Increase use of renewable resources.
8) Reduce deforestation.
9) Use office machines in well ventilated areas.
10) Remove Nox from motor vehicular exhaust.