The pesticides and herbicides which are widely used in agriculture have no doubt increased agricultural output. Chemically these are chlorinated hydrocarbons and organophosphates. The former include DDT (Dichloro- diphenyl trichloroethane), dieldrin, aldrin, etc. These compounds are highly toxic, and water soluble. Some amounts of these compounds can be expected to be preset in fruits, vegetables, and water.
Some quantity of these compounds reaches the human body along with food and water. Human body does not have the enzymes to metabolise such compounds into harmless ones. These are a tendency for these compounds to be accumulated in the liver and in fatty tissue. The presence of such compounds causes harm to the central nervous system (brain and spinal cord). The organophosphates are parathion, Malathion, diazinon, and phosdrin, etc. These compounds can also affect the central nervous system and may cause death.