Question

Why should the spraying of DDT as an insecticide on vegetable crops be banned? Explain

Answer 1

because it increases bio magnification

Answer 2

It is because they can cause bio magnifications.  It is an increasing concentration of the substances like toxic chemicals in tissues of the tolerant organisms at higher levels present in the food chain.  

It is due to various reasons including food chain energetic, persistence, non-existent or low rate of the internal degradation.

It also refers to the task whereby some substances like heavy metals or pesticides work their path into water bodies.