Biomagnification

CORE DEFINITION

Biomagnification (also known as biological magnification, bioamplification, or biological enrichment) refers to the phenomenon in which the concentration of a chemical substance in the natural environment progressively increases in organisms at each trophic level along the food chain. For example, the concentration of DDT or mercury increases along the food chain. The main reason for biomagnification is that once these harmful substances enter an organism, they are not easily excreted; they only enter and do not leave, accumulating step by step, eventually reaching concentrations in top predators that may be millions of times higher than in the original environment. The reasons for this increase may include: persistence - the substance cannot be broken down by environmental processes; food chain energetics - as it moves up the food chain, the concentration of the substance gradually increases; low or non-existent internal degradation or excretion rate of the substance - often due to its insolubility in water. For example, in a food chain such as: aquatic plants, small fish, osprey, birds of prey.