CBSE Class 10 Answered

This happens because creatures high up in the food chain, such as predators, feed on creatures that are lower in the food chain and absorb the substances from the organisms they consume in addition to the substances they directly absorb from the environment. In some cases, the process of biological magnification can be harmful to the organisms high up in a food chain because they absorb harmful substances from all of the organisms they consume.

For example – There is frequent washing down of several pesticides and other chemicals used in crop fields down into the soil or into the water bodies. From the soil, these are absorbed by the plants, and from the water bodies these are taken up by aquatic plants and animals. This is one of the ways in which they enter the food chain. As these chemicals are not degradable, these get accumulated progressively at each trophic level. As human beings occupy the top level in any food chain, the maximum concentration of these chemicals gets accumulated in our bodies.