Pesticides are important pollutants of soil. They include insecticides, fungicides, algicides, rodenticides and weedicides.
Pesticides are generally broad spectrum and function as biocides killing plants and microorganisms.
Organochlorines and chlorinated hydrocarbons are an important class of pesticides. The important ones are dichloro diphenyl trichloro ethane (DDT), Benzene hexachloride (BHC), aldrin, dieldrin and endrin. They are persistent, fat soluble, and show biomagnification and hence, are harmful to higher trophic level of organisms.