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Pesicide transformation products
1,. Somasundaram and Joel R. Coats, eds., Pesiicidr Trms~ormarion Produm, ACS Symp. Ser. 459,
ACS, Washington DC, 1991, $64.95.
For those who think the use and application of pesticides from a chemical view point is a simple or an tutresearched field, this book will be a real eye-opener. The book is divided into three sections entitled “Overviews”, “Fate” and “Significance.” There arc 20 chapters, all of which give a very liberal number of references. Overall more than SO0references are cited. The area of pesticide transformation products is comparatively new. As is stated in chapter 20, written by the editors: Although research on synthetic pesticides has been conducted for the past 50 years, most rfforts have focused on the parent compounds. Little attention has been paid to the fate and signiticance of the products formed from pesticide transformation. This has been due to: ( I ) the low concentrations at which such products are formed in the environment; (2) the assumption that pesticides are generally mineralized to insiguiticant products; (3) lackofsuitable analytic techniques. While no controlled release techniques are discussed in the book, and neither microencapsulation nor controlled release tonics are listed in the index, the material covered here should be of great interest to anyone who would attempt to modify the qualities of a pesticide introduced into the environment. The successful formulation of controlled release pcsticides requires a knowledge of the mode of failure that formu!ation would attempt to modify. Without that understanding, the process becomes one of serendipity rather than science. This might be called a source book of problems awaiting the application of Controlled Release Technologies. The transformation products of some pesticides are of great signiWcance in the environment. Generally n cleavage of a molecute results in products that are more hydrophilic than the parents and thus more of a threat to result in ground water contamination than tests on the parent molecule would have indicated. Another problem is that environmental degradation pathways vary tremendously with the different application site parameters such as application method, soil type, microbes, temperature, moisture. Molecular species formed in the environ.
ment from a single pesticide can vary widely. The determination of the safety of use of a particular material in the past has been a factor of the hazard associated with the material itself and the amount present. It is however, becoming more and more apparent that hazard may also be due to the environmenta! transformation products. Furthermore, the formation of primary degradation products is not necessarily the end of the process. Secondary or tertiary degradation products may have signiticance. In the case of many pesticides these products may not be known or analytic methods for tbeir detection may not be in place. Thus potential problems are not apparent. Some applied materials are precursors to the active pesticide, such as methyl parathion which is oxidized to methyl panoxon, carbosulfan hydrolyzed to carbofuran, o: benomyl which fimctions as carbendazim in the environment, etc. In some of these situations the toxicity of the bans formation product can be higher than the ap plied pesticide. Perhaps the most important aspect of pesticide transformation products concerns the effects of state and federal regulations on future pesticide use. Chapter I8 by BeIluck et al. gives us an in depth look at the risk assessment, po!icy and legal implications of ground water contamination by atrazine and its metabolites. Atrazme which is a possible human carcinogco is detected in ground water 10 to 20 times more frequently than any other pesticide. Atrazinc’s metabolites which are of unknown toxicity are assumed to be of the same order of toxicity as atrazine itself. Therefore the amount of atrazine detected is defined for regulatory purposes as the sum ofatraziae plus its metabolites. This numbc: can exceed the legal limits set for atrazine in ground water even in cases where no atrazioe hut only the metabolites are found. Anally, ignorance of the pesticide transformation products, results in nondetection which results in nonregulation. Nonregulation along with inadequate groundwater monitoring programs can seriously mislead us as to the safety of our drinking water. R.C. KOESTLER
aro&,n NorrhArncvirn
ACS, Washington DC, 1991, $64.95.
For those who think the use and application of pesticides from a chemical view point is a simple or an tutresearched field, this book will be a real eye-opener. The book is divided into three sections entitled “Overviews”, “Fate” and “Significance.” There arc 20 chapters, all of which give a very liberal number of references. Overall more than SO0references are cited. The area of pesticide transformation products is comparatively new. As is stated in chapter 20, written by the editors: Although research on synthetic pesticides has been conducted for the past 50 years, most rfforts have focused on the parent compounds. Little attention has been paid to the fate and signiticance of the products formed from pesticide transformation. This has been due to: ( I ) the low concentrations at which such products are formed in the environment; (2) the assumption that pesticides are generally mineralized to insiguiticant products; (3) lackofsuitable analytic techniques. While no controlled release techniques are discussed in the book, and neither microencapsulation nor controlled release tonics are listed in the index, the material covered here should be of great interest to anyone who would attempt to modify the qualities of a pesticide introduced into the environment. The successful formulation of controlled release pcsticides requires a knowledge of the mode of failure that formu!ation would attempt to modify. Without that understanding, the process becomes one of serendipity rather than science. This might be called a source book of problems awaiting the application of Controlled Release Technologies. The transformation products of some pesticides are of great signiWcance in the environment. Generally n cleavage of a molecute results in products that are more hydrophilic than the parents and thus more of a threat to result in ground water contamination than tests on the parent molecule would have indicated. Another problem is that environmental degradation pathways vary tremendously with the different application site parameters such as application method, soil type, microbes, temperature, moisture. Molecular species formed in the environ.
ment from a single pesticide can vary widely. The determination of the safety of use of a particular material in the past has been a factor of the hazard associated with the material itself and the amount present. It is however, becoming more and more apparent that hazard may also be due to the environmenta! transformation products. Furthermore, the formation of primary degradation products is not necessarily the end of the process. Secondary or tertiary degradation products may have signiticance. In the case of many pesticides these products may not be known or analytic methods for tbeir detection may not be in place. Thus potential problems are not apparent. Some applied materials are precursors to the active pesticide, such as methyl parathion which is oxidized to methyl panoxon, carbosulfan hydrolyzed to carbofuran, o: benomyl which fimctions as carbendazim in the environment, etc. In some of these situations the toxicity of the bans formation product can be higher than the ap plied pesticide. Perhaps the most important aspect of pesticide transformation products concerns the effects of state and federal regulations on future pesticide use. Chapter I8 by BeIluck et al. gives us an in depth look at the risk assessment, po!icy and legal implications of ground water contamination by atrazine and its metabolites. Atrazme which is a possible human carcinogco is detected in ground water 10 to 20 times more frequently than any other pesticide. Atrazinc’s metabolites which are of unknown toxicity are assumed to be of the same order of toxicity as atrazine itself. Therefore the amount of atrazine detected is defined for regulatory purposes as the sum ofatraziae plus its metabolites. This numbc: can exceed the legal limits set for atrazine in ground water even in cases where no atrazioe hut only the metabolites are found. Anally, ignorance of the pesticide transformation products, results in nondetection which results in nonregulation. Nonregulation along with inadequate groundwater monitoring programs can seriously mislead us as to the safety of our drinking water. R.C. KOESTLER
aro&,n NorrhArncvirn