Biomagnification refers to toxins increasing in concentration higher up the food chain.

• A. True
• B. False
• C. Only for metals
• D. Only for pesticides

Answer: (A)

Biomagnification occurs when a toxin becomes more concentrated in organisms higher up a food chain because the substance is persistent, fat-loving, and not easily eliminated. An animal at a lower trophic level may accumulate a certain amount of toxin from its diet. When a predator eats many of these contaminated prey, it accumulates the toxin from each meal, and because it retains much of what it ingests, the toxin concentration in the predator’s tissues rises. With continued feeding on contaminated prey, top predators end up with the highest levels. This pattern is well documented for substances like methylmercury and certain persistent organic pollutants (for example, PCBs and historically, DDT). It’s not limited to metals or pesticides; any toxin that is persistent and not readily excreted can show biomagnification, whereas non-persistent substances or those quickly metabolized tend not to.