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Environmental issues

Biology Index

Radioactive pollution

It is degradation of environment due to the release of radioactivity. Radioactivity is measured in units called roentgens or ‘r’.

  1. Background radiation It is radiation level found naturally in biosphere due to cosmic rays reaching earth and radio-nuclides found in earth’s crust. The naturally occurring radioactive elements are Uranium-232, Uranium-235, Thorium-232, Radium-224, Radon-222, Potassium-40 and Carbon-14.
  2. Man-made radiation They are due to mining and refining of radioactive elements like plutonium, uranium,and Thorium, nuclear power plants and fuels, preparation of radioactive isotopes, production and explosion of nuclear weapons.

Nuclear weapons

They use Uranium-235, Plutonium-239 for fission and hydrogen or lithium as fusion material.
A nuclear explosion produces:
  1. Uncontrolled chain reaction.
  2. Tremendous heat.
  3. Neutron flux that changes another element to radioactive state.
  4. Unused explosive and activation products.
  5. A lot of radioactive and other gases forming mushroom type cloud.

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Radioactive elements and its effects.

Atomic reactors

They employ controlled radioactive fission, fusion for the liberation of energy.
  1. The coolant water causes thermal pollutions.
  2. A small amount of radioactivity enters coolant water which undergoes magnification to some 75,000 times in birds.
  3. They release halogen and inert gases.
  4. A mishap can be dangerous as an atomic explosion.
  5. Radioactive waste is highly pollutant and its dumping requires several precautions – first cooling in small ponds for 50 -100 years and then packing in special containers, which are buried some 500 meters deep in rocks or at the bottom of the ocean.

Harmful effects of radioactive radiations

They were first recorded in 1909 in uranium miners as skin burns and cancer. Young and recently divided cells become easily damaged. Short range effects are a loss of nails and hair, bleeding, the changed proportion of blood cells changed metabolism. Long range effects are tumours, cancer, mutations, genetic deformities.

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