2. is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable.

3.  nuclear bomb  improper storage of radioactive materials  leakage of nuclear installations  emissions of radioactive gases as a result of the explosion at the nuclear power plant

4. Duration of radioactive contamination ranging from several hours to several weeks or even months and years. This time depends on the persistence of radioactive elements

5.  chemical method  photographic method  luminescent method  ionization method

6. Contaminated food is not suitable for eating, because in this way hazardous substances can be associated with the cells of the body, resulting in a greater and longer exposure to ionizing radiation than the superficial irradiation. It is also impossible to purify the contaminated water or food in the home conditions.

7. On the contaminated area we don’t have the resources to live. All grain and crops are dying or absorb radioactive substances themselves become a source of radiation exposure. People and livestock from contaminated areas subjected to less deactivation and transported outside the area contaminated.