Biomagnification raises persistent toxin concentrations at higher trophic levels because consumers ingest many contaminated organisms and cannot rapidly eliminate pollutants.
Coverage 2012–2025 · Updated 16 Jul 2026
Biomagnification is increasing tissue concentration of a persistent pollutant in consumers at successively higher trophic levels.
DDT and mercury are retained or eliminated slowly. Predators consume many contaminated prey, so their total intake produces a higher tissue concentration than in organisms below them.
Mercury can be low in water or plankton, higher in fish and highest in fish-eating birds or mammals; DDT similarly reached damaging concentrations in top predators.
Bioaccumulation is increase within one organism over time; biomagnification is increase between trophic levels. Not every pollutant does either.
This objective is assessed through essay response, commonly using Explain / Define / State.
Explain / Define / State / Discuss / Identify / Suggest / Deduce / Outline / Justify
Build the answer around this relationship: Biomagnification requires a pollutant that persists and accumulates in organism tissues.
Describing biomagnification as any pollution effect, without explaining increasing concentration at successive trophic levels.
Representative question
Discuss the use of DDT (dichlorodiphenyltrichloroethane) in the control of the malarial parasite.
Core D4.2 is secure when students can judge whether a system is being stabilized or pushed toward change. The route is: identify the stability support or disturbance, explain the mechanism, and state the ecosystem consequence using evidence.
Core transfer questions ask students to explain why an ecosystem remains stable or why a disturbance pushes it toward change. Strong answers do not list threats; they explain mechanisms such as lost rainfall recycling, trophic cascade, overharvest, nutrient enrichment, toxin biomagnification, plastic movement, or restoration through rewilding.
