Bio concentration of pesticides means accumulation of pesticides in the living organisms like plants, men and animals.
Pesticides are poisonous chemical substances which are sprayed over crops to protect them from pests i.e. small harmful animals and diseases. These chemical pesticides mix up with the soil and water. From soil and water, these pesticides are absorbed by the growing plants along with water and other minerals.
When herbivorous animals eat plant food then these poisonous chemical pesticides go into their bodies through the food chain. Similarly when the carnivorous eat herbivores then the pesticides get transferred to their bodies. Human beings eat plant food as well as herbivores. So the pesticides present in plant food and herbivores also get transferred to the man’s body through food. In this way the pesticides enter the food chain at the producer level i.e. plant level and in the process of transfer of food through trophic levels, these harmful chemicals get concentrated at each trophic level. This is called bio concentration of pesticides.