Why are PFAS called 'forever chemicals'?

• A. They do not easily break down in the environment and can remain in the body for years due to their long carbon chains.
• B. They degrade quickly.
• C. They are essential in water treatment.
• D. They evaporate quickly.

Answer: (A)

The defining idea is persistence: PFAS are extremely stable because of strong carbon–fluorine bonds, which resist breakdown in the environment and in the body. This makes them hard to degrade through natural processes like sunlight, heat, or microbial action, so they remain for years after release. They can also bioaccumulate, leading to long biological half-lives in humans and wildlife. That combination of environmental and biological persistence is why they’re called “forever chemicals.” The other statements don’t fit because PFAS are not known for rapid degradation, they aren’t universally essential for water treatment, and they do not evaporate quickly.