Biomagnification meaning – UGC NET Question

Biomagnification occurs when chemicals that are persistent and fat-soluble accumulate in organisms and become more concentrated at higher trophic levels. Predators eat many prey items, each containing stored pollutants, leading to a build-up in their bodies over time. Substances such as DDT and methylmercury are well-known examples that biomagnify. The definition referring to progressive increase in concentration at successive trophic levels therefore correctly describes this process.

Option A:
Option A is incorrect because biomagnification is about pollutant concentration, not species richness. The number of species in a food chain is a separate ecological attribute.

Option B:
Option B is incorrect even though energy does diminish at higher trophic levels due to inefficiencies. That phenomenon relates to ecological pyramids and energy flow, not to the accumulation of contaminants.

Option C:
Option C is correct as it highlights both the persistence of certain chemicals and their tendency to move up the food chain. This explains why top predators, including humans, can face health risks even when environmental concentrations appear low.

Option D:
Option D is incorrect; microbial multiplication in sewage plants is part of biological treatment and waste breakdown. It does not involve the stepwise concentration of pollutants at different trophic levels.