Degradation of Pesticides in the Environment
85
degradation pathways of individual compounds. Rather, the classes of reactions
and similar interactions were grouped together for the sake of clarity. Naturally
many of the reactions may occur on one compound, and as a result could yield
complicated interacting reaction patterns. Furthermore, in the environment other
factors-such as redox potential, nutritional state of soil, availability of catalytic
material, pH, physical adsorption and absorption, and physiochemical changes
(e.g., emulsification and liposolubilization}-would greatly affect the eventual
outcome of the expression of the degradative activities. What one has to remember, however, is the simple fact that certain chemical properties make the
compounds susceptible to these degradative forces. For instance, the N-chlorine
atoms of triazine herbicides are labile, and so are the carboxyl esters of malathion.
Thus, the advantage of studying basic reaction mechanisms is that the patterns
of degradation of chemicals in the environment become explainable and even
predictable as such knowledge accumulates. Well-informed scientists in this field
should be capable of examining the molecular structure of a new compound,
identifying its labile moieties, and coming up with a reasonable prediction of
the pattern and mechanisms of its degradation.
REFERENCES
Ahmed, M. K., and Focht, D. D., 1972, Degradation of polychlorinated biphenyls by two species
of Achromobacter, Can. J. Microbiol. 19:47.
Benezet, H., and Matsumura, F., 1973, Isomerization of 'Y-BHC to a-BHC in the environment,
Nature (London) 243:480.
Castro, C. E., 1964, The rapid oxidation of iron (II) porphyrines by alkyl halides. A possible mode
of intoxication of organisms by alkyl halides, J. Am. Chem. Soc. 86:2310.
Cook, J. W., 1957, In vitro destruction of some organophosphate pesticides by bovine rumen fluid,
J. Agric. Food Chem. 5:859.
Crosby, D. G., and Leitis, E., 1969, Photolysis of chlorophenylacetic acids, J. Agric. Food Chem.
17:1036.
Csetjesi, A. J., and Johnson, E. L., 1972, Methylation of pentachlorophenol by Trichoderma
virgatum. Can. J. Microbiol. 18:45.
DeBaun, J. R., and Menn, J. J., 1976, Sulfoxide reduction in relation to organosphosphorus insecticide detoxication, Science 191: 187.
Esaac, E. G., and Matsumura, F., 1978, A novel reduction system involving flavoprotein in the rat
intestine, Bull. Environ. Contam. Toxicol. 19:15.
Esaac, E. G., and Matsumura, F., 1979, Mechanisms of reductive dechlorination of DDT by rat
liver microsomes, Peslie. Biochem. Physiol. 13:81.
Esaac, E. G., and Matsumura, F., 1980, Metabolism of insecticides by reductive systems, Pharmacol. Ther. 9:1.
Focht, D. D., and Alexander, M., 1970a, DDT metabolites and analogs: Ring fission by Hydrogenomonas. Science 170:91.
Focht, D. D., and Alexander, M., 1970b, Aerobic cometabolism of DDT analogues by Hydrogenomonas sp., J. Agric. Food Chem. 19:20.
85
degradation pathways of individual compounds. Rather, the classes of reactions
and similar interactions were grouped together for the sake of clarity. Naturally
many of the reactions may occur on one compound, and as a result could yield
complicated interacting reaction patterns. Furthermore, in the environment other
factors-such as redox potential, nutritional state of soil, availability of catalytic
material, pH, physical adsorption and absorption, and physiochemical changes
(e.g., emulsification and liposolubilization}-would greatly affect the eventual
outcome of the expression of the degradative activities. What one has to remember, however, is the simple fact that certain chemical properties make the
compounds susceptible to these degradative forces. For instance, the N-chlorine
atoms of triazine herbicides are labile, and so are the carboxyl esters of malathion.
Thus, the advantage of studying basic reaction mechanisms is that the patterns
of degradation of chemicals in the environment become explainable and even
predictable as such knowledge accumulates. Well-informed scientists in this field
should be capable of examining the molecular structure of a new compound,
identifying its labile moieties, and coming up with a reasonable prediction of
the pattern and mechanisms of its degradation.
REFERENCES
Ahmed, M. K., and Focht, D. D., 1972, Degradation of polychlorinated biphenyls by two species
of Achromobacter, Can. J. Microbiol. 19:47.
Benezet, H., and Matsumura, F., 1973, Isomerization of 'Y-BHC to a-BHC in the environment,
Nature (London) 243:480.
Castro, C. E., 1964, The rapid oxidation of iron (II) porphyrines by alkyl halides. A possible mode
of intoxication of organisms by alkyl halides, J. Am. Chem. Soc. 86:2310.
Cook, J. W., 1957, In vitro destruction of some organophosphate pesticides by bovine rumen fluid,
J. Agric. Food Chem. 5:859.
Crosby, D. G., and Leitis, E., 1969, Photolysis of chlorophenylacetic acids, J. Agric. Food Chem.
17:1036.
Csetjesi, A. J., and Johnson, E. L., 1972, Methylation of pentachlorophenol by Trichoderma
virgatum. Can. J. Microbiol. 18:45.
DeBaun, J. R., and Menn, J. J., 1976, Sulfoxide reduction in relation to organosphosphorus insecticide detoxication, Science 191: 187.
Esaac, E. G., and Matsumura, F., 1978, A novel reduction system involving flavoprotein in the rat
intestine, Bull. Environ. Contam. Toxicol. 19:15.
Esaac, E. G., and Matsumura, F., 1979, Mechanisms of reductive dechlorination of DDT by rat
liver microsomes, Peslie. Biochem. Physiol. 13:81.
Esaac, E. G., and Matsumura, F., 1980, Metabolism of insecticides by reductive systems, Pharmacol. Ther. 9:1.
Focht, D. D., and Alexander, M., 1970a, DDT metabolites and analogs: Ring fission by Hydrogenomonas. Science 170:91.
Focht, D. D., and Alexander, M., 1970b, Aerobic cometabolism of DDT analogues by Hydrogenomonas sp., J. Agric. Food Chem. 19:20.