Final answer:
Biomagnification is the term used to describe the increase in concentration of a contaminant at each level of the food chain. An example of this is the accumulation of the pesticide DDT in birds via the food chain, which led to significant reductions in their population.
Step-by-step explanation:
The term for the incremental increase in the concentration of a contaminant at each level of the food chain is known as biomagnification. This is the process by which a type of toxin increases its concentration as it passes up the chain.
For instance, a small amount of toxic substance ingested by plants might not be harmful for them, but as herbivores eat these plants and carnivores eat herbivores, the toxin becomes more concentrated and harmful.
An iconic example of biomagnification, explained in the 1960s bestseller Silent Spring by Rachel Carson, is the impact of the pesticide dichlorodiphenyltrichloroethane (DDT). DDT was widely used before its devastating effects were recognized.
In aquatic ecosystems, DDT was ingested by small organisms which were then eaten by bigger ones and eventually reached birds. As a result, birds accumulated enough DDT to cause their eggshells to become fragile and break, leading to a reduction in their population.
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