Which option correctly defines biomagnification?

• A. The increase in chemical concentration in animal tissues as the chemical moves up the food chain
• B. The decrease in chemical concentration up the food chain
• C. The spread of pollutants through water
• D. The accumulation of pollutants within a single organism

Answer: (A)

Biomagnification is the increase in chemical concentration in animal tissues as the chemical moves up the food chain. When a persistent pollutant is eaten by prey, it accumulates in that prey’s tissues. The predator then consumes many contaminated prey, and because the chemical is not easily excreted or metabolized, its concentration builds up in the predator’s body. With each step up the chain, higher trophic levels end up with greater levels of the chemical, sometimes reaching harmful amounts in top predators and even in humans who eat those animals.

This concept is different from a decrease in concentration up the food chain, which would be the opposite pattern. It’s not just about pollutants spreading through water, which describes dispersion rather than trophic transfer. It’s also not limited to accumulation within a single organism (bioaccumulation) unless that accumulation is observed across multiple trophic levels; biomagnification specifically describes the rising concentration across predators at higher levels.