In relation to radiation, what does "contamination" mean?

Contamination refers to the presence of radioactive materials on surfaces, in the air, or within living organisms. When radioactive atoms from a source are dispersed and adhere to objects, this is identified as contamination. It is crucial in the context of radiation safety, as contamination can pose significant health risks by allowing radiation to interact with people or the environment.

The first choice describes radiation being present in non-radioactive areas, which could imply an area is exposed to radiation but does not directly address the physical presence of radioactive materials. The third choice discusses shielding material deteriorating, which relates to safety measures against radiation rather than contamination itself. The last choice refers to the variability of radiation levels, which is more about monitoring radiation exposure rather than the physical presence of radioactive substances. Thus, identifying contamination specifically as the spread of radioactive atoms clarifies why this option is correct, emphasizing the importance of understanding and managing contamination in radiological safety practices.