The correct answer is Biomagnification.
Biomagnification can be defined as the gradual increase in the concentration of the toxic chemicals at each trophic level. Lowest at the producers and highest at the higher trophic level.
The toxic chemicals such as industrial waste, radioactive waste that enters in the food chain and starts effecting the health of the plants and animals and its concentration increases at each trophic level.
The toxic chemicals gets transferred from the producers to consumers (predators except the primary consumers) and during this transfer the concentration increases.