ABSTRACT
Pesticides are grouped into four major classes-insecticides, herbicides, fungicides, and rodenticides. The usage of pesticides worldwide has increased dramatically over the past two decades, with changes in farming practices and progressively demanding agricultural requirements. Pesticides are known to control hundreds of weed species, more than a million harmful insects, and approximately 1500 plant diseases (Ware and Whitacre 2008). It has been projected that approximately one-third of the crop production is lost if pesticides are not applied (Tadeo 2008). The use of plant protection compounds brings about progress in the food availability by reducing losses on the eld and during storage. In both the developed and developing countries, the crop losses due to various pests are estimated between 10% and 75% depending upon the climate, environmental factors, and crop practices (WHO 1990). This makes the application of different insecticides, herbicides, fungicides inevitable for achieving better crop protection and storage. It is estimated that countries of the European Union (EU) consume more than 300,000 tons of pesticides annually on crop protection (Stocka et al. 2011). The world’s pesticide expenditure at user end was found to be a total of 39.443 million dollars in 2007 with United States representing the largest part spending 12.454 million dollars (Grube et al. 2011). In the list of pesticide consumption, herbicides
25.1 Introduction .................................................................................................................................. 697 25.1.1 Herbicides ........................................................................................................................ 698 25.1.2 Fungicides ........................................................................................................................ 699 25.1.3 Regulation ........................................................................................................................ 703
25.2 General Strategies for the Analysis of Herbicide and Fungicide Residues in Water ................... 703 25.2.1 Sampling .......................................................................................................................... 703 25.2.2 Extraction/Preconcentration of Samples ......................................................................... 704
25.2.2.1 Direct Aqueous Injection ................................................................................. 729 25.2.2.2 Solvent Less Techniques .................................................................................. 729 25.2.2.3 Solvent-Based Techniques ................................................................................731
