Which of the following best describes the three contamination types?

• A. Fixed contamination, loose contamination, and discrete radioactive particles
• B. Surface contamination, airborne contamination, and environmental contamination
• C. External contamination, internal contamination, and surface contamination
• D. Mixed contamination, diffuse contamination, and localized contamination

Answer: (A)

The main idea being tested is how contamination is classified by its physical state and how it behaves on surfaces. Fixed contamination is contamination that is firmly bound to a surface and not easily removed by ordinary cleaning. It may require more rigorous decontamination methods or time to allow decay, and it remains attached despite light wiping. Loose contamination, on the other hand, is not firmly attached and can be wiped or brushed away with standard decontamination practices. It’s removable with routine cleaning because it isn’t bonded to the surface. Discrete radioactive particles are individual, separate particles rather than a film or residue; they can be spread or dispersed if disturbed and can pose a different risk, such as inhalation or ingestion, if not handled carefully.

This framing—fixed, loose, and discrete particles—directly describes the three physical forms contamination can take on surfaces, which is why it’s the best answer. Other options talk about where contamination is found (surface, airborne, environmental) or about exposure routes (external, internal) or use less standard terms, which don’t capture the specific ways contamination adheres or remains present on surfaces.