With reference to the sources of water pollutants answer the following questions:

What are the sources of radioactive pollution? Describe each of them.

The two main sources of radioactive pollution are-

1. Natural sources — These sources are cosmic rays with energetic radiations reaching the earth from outer space. Though they are a major hazard in space, they are not dangerous for organisms on earth.
2. Man made sources — The following sources cause radioactive pollution-
   1. X-rays waste — The use of X-rays is common for detecting skeletal disorders. Cancer patients undergo radium and other isotope radiations. The X-rays pass through genetic cells and affect the chromosomes, resulting in mutations.
   2. Radioactive fallout from nuclear plants — In a nuclear power establishment, both fuel elements and coolants are sources of radiation pollution. Radioactive wastes from atomic reactors are hazardous to living organisms. Even if radioactive wastes are buried underground they may escape into the surroundings. Inert gases escape as vapours and pollute the environment.
   3. Nuclear weapons — Testing of nuclear weapons involves using radioactive substances like Uranium 235 and Plutonium 239 for fission. The radioactive waste emitted during these tests makes the surrounding materials radioactive.
      Radioactive particles are carried away to distant places by wind. They are brought down by rain. Raindrops containing these radioactive particles fall on earth and affect the soil causing pollution. From the soil, the radioactive materials reach water sources, where the aquatic organisms absorb and accumulate them through the food chains and pass them on to human beings.
   4. Radioactive isotopes — Radioactive isotopes are used in research laboratories. When the waste water from these laboratories reaches the rivers, streams, lakes etc., through the sewers they cause water pollution.