Because energy transformations are only ~10% efficient, higher trophic levels must consume more prey to meet energy needs

If a pollutant is ingested by living organisms, it will become concentrated at higher trophic levels as they eat more exposed prey

  • The increase of a substance (such as a pollutant) in a particular organisms is called bioaccumulation
  • The increase in the concentration of a substance at a particular trophic level is called biomagnification

Bioaccumulation refers to how pollutants enter a food chain, whereas biomagnification refers to the tendency of pollutants to concentrate as they move from one trophic level to the next

Because pollutants become concentrated by biomagnification, higher trophic levels are more susceptible to their toxic effects

  • The pesticide DDT caused egg-shell thinning and population declines in species of birds that fed on exposed insects 
  • Heavy metals (like mercury) released into waterways via industrial processes may become concentrated in fish

Principle of Biomagnification

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  Click on the diagram to show representation of chemical concentration and relative toxic effects