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Contents
Chapter 2
Pesticide Metabolism in Plants: Reactions and Mechanisms
Richard H. Shimabukuro, Gerald L. Lamoureux, and
D. Stuart Frear
2.1.
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21
2.2.
Pesticide Metabolism in Plants. . . . . . . . . . . . . . . . . . . . . . . . . . .. 22
2.2.1. Absorption.................................... 22
2.2.2. Translocation and Distribution .................... 22
2.2.3. Metabolism.................................... 23
2.3.
Degradation Reactions of Pesticides in Plants. . . . . . . . . . . . . . .. 23
2.3.1. Oxidation..................................... 24
2.3.2. Reduction..................................... 36
2.3.3. Hydrolysis..................................... 37
2.3.4. Conjugation................................... 42
2.3.5. Bound or Insoluble Residues. . . . . . . . . . . . . . . . . . . . .. 56
2.4.
Conclusion ............................................ 57
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58
Chapter 3
Degradation of Pesticides in the Environment by Microorganisms
and Sunlight
Fumio Matsumura
3.1.
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
3.2.
Characteristics of Microbial Metabolism .................... 68
3.2.1. Enzymatic Degradation .......................... 69
3.2.2. Criteria for Distinguishing One Type of Metabolism
from Another . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 70
3.3.
Commonly Occurring Metabolic Processes in Microorganisms.. 73
3.3.1. Hydrolytic Processes ............................ 73
3.3.2. Reductive Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 75
3.3.3. Oxidative Reactions. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 77
3.4.
Other Metabolic Reactions Related to Pesticide Degradation. . .. 79
3.4.1. Dehydrochlorination............................. 79
3.4.2. Isomerization.................................. 79
3.4.3. Synthetic Metabolism. . . . . . . . . . . . . . . . . . . . . . . . . . .. 80
3.4.4. Polymerization................................. 80
3.5.
Degradation by Sunlight and Other Physical Factors. . . . . . . . . .. 81
3.5.1. Hydrolysis: Nucleophilic Reaction. . . . . . . . . . . . . . . .. 82
3.5.2. Dehalogenation................................. 83