Which term describes the buildup of chemicals in living organisms over time?

• A. Degradation
• B. Excretion
• C. Dilution
• D. Bioaccumulation

Answer: (D)

Buildup of chemicals in living organisms over time is bioaccumulation. It happens when a substance is taken in faster than it can be eliminated, so it gradually accumulates in tissues—especially if the chemical is persistent and fat-soluble. The organism’s internal concentration can rise even as environmental levels stay the same or decrease, creating a body burden that can heighten toxic risk. This differs from degradation (the chemical breaking down), excretion (the body removing substances), or dilution (the chemical becoming less concentrated in the environment). In occupational hygiene, bioaccumulation helps explain why long-term exposure to certain substances can lead to higher internal doses than short-term measurements might suggest, guiding monitoring and control decisions.