Water pollution, toxicity and biomagnification
≈ 48 minWater pollution, toxicity and biomagnification
Pollutants enter water through sewage, industry, agriculture, mining, litter and runoff. Some nutrients cause eutrophication: algal growth increases, decomposition uses dissolved oxygen and aquatic animals may suffocate. Persistent toxins can accumulate in organisms and become more concentrated at higher trophic levels through biomagnification. The route, dose, duration and organism determine risk; not every pollutant behaves in the same way.
Work it through
Fertiliser runoff enriches a dam. Algae multiply, then die. Bacteria decompose the dead algae and use oxygen. Fish may die because dissolved oxygen falls, not because algae 'eat' the fish.
Mastery target
Trace a pollutant from source to ecosystem effect and distinguish accumulation within one organism from biomagnification across a food web.
What directly causes fish deaths late in an eutrophication event?
Name the key biological term from Water pollution, toxicity and biomagnification: enter the term that best fits the explanation and visual model.
Where would a persistent toxin often reach the highest concentration in a food web?
Which statement corrects a common misunderstanding in Water pollution, toxicity and biomagnification?