A large number of pesticides and chemical are used to protect our crops from pest and ****. Some of these chemicals are washed down into the soil, while some enter in the water bodies. From the soil, they are absorbed by plants along with water and minerals and from water bodies, they are taken up by aquatic plants and animals. As these chemicals cannot decompose, they accumulate progressively at each trophic level. As the food chain proceeds, the concentration of pesticides also increases. This increase in the concentration of harmful chemical with each step of the food chain is called biomagnification. That is why food grains, vegetables, fruits and meat contain pesticide residue.
