ABSTRACT
Extensive use of pesticides has facilitated an increase in agricultural productivity, despite a decrease in the total acreage of land under actual cultivation. This chapter attempts to focus attention on the various means through which pesticide residues reach the aquatic environment and the hazards to the aquatic organisms resulting from the excessive use of pesticides. Pesticides that are transported to the aquatic environment are primarily of agricultural origin; they may also arise as effluents from manufacturing and formulating plants. The atmospheric transport of residues to the aquatic ecosystem has been dealt with. Two sources of contamination of the aquatic ecosystem are recognized: point and nonpoint. Aquatic organisms are affected by pesticides, although often the aquatic environment is not the primary site of application of pesticides. Two factors ultimately contribute to the concentration of the pesticides in the aquatic ecosystem: persistence of pesticides in the soils and long-range transport of the pesticides in the atmosphere.
