52
Pesticides, Organic Contaminants, and Pathogens in Air
Some of the major reactions of pesticides include N- and O-dealkylations,
exemplifed by trifuralin N-dealkylation; photolytic decomposition, exemplifed by methyl isothiocyanate to the more toxic and more stable methyl
isocyanate (see Chapter 8); and oxidations: mercaptans and disulfdes to SO 2 ,
thions to oxons, and merphos (S,S,S-tributyl phosphorotrithioite) to its trithioate conversion product Def (Woodrow et al., 2018). Polycyclic aromatic
hydrocarbons (PAHs) such as dibenzanthracene that are released during
plant biomass burning are activated to epoxide forms that are prominent
mutagens and carcinogens (Chapter 4). But photoreactions of pesticides
in fog and air represents an area which warrants further work in terms of
mechanisms and rates.
Reactions of pesticides in air, as well as in moisture and particulate matter
in air, are not negligible and require considerations that must be studied by
companies during pesticide registration. Understanding these reactions has
led to discontinued use of some heavily used pesticides, and it helps understand the fate of pesticides and their long-range transport. The implications
of this are discussed more in Chapter 10.
3.6 Conclusions
No environmental compartment (water, soil, air, biota) exists in isolation.
After an intentional or accidental release, a chemical contaminant will be distributed to varying degrees among the various compartments, depending on
the properties of the chemical (organic content, water solubility, vapor pressure, diffusion coeffcient, BCF) and the environmental conditions. In these
different compartments, transformations may occur for reactive chemicals.
The concepts covered in this chapter should contribute to a better understanding of the environmental fate of chemical contaminants, leading to a
more confdent answer to the question “where did that chemical go?” Clearly
more work is needed, particularly on transformation of pesticides and other
contaminants, including viruses in air.
References
Angermann, J.E., Fellers, G.M., and Matsumura, F. (2002). Polychlorinated biphenyls and toxaphene in Pacifc tree frog tadpoles (Hyla regilla) from the
California Sierra Nevada, USA. Environ. Toxicol. Chem. 21(10), 2209–2215. DOI:
10.1002/etc.5620211027.
Pesticides, Organic Contaminants, and Pathogens in Air
Some of the major reactions of pesticides include N- and O-dealkylations,
exemplifed by trifuralin N-dealkylation; photolytic decomposition, exemplifed by methyl isothiocyanate to the more toxic and more stable methyl
isocyanate (see Chapter 8); and oxidations: mercaptans and disulfdes to SO 2 ,
thions to oxons, and merphos (S,S,S-tributyl phosphorotrithioite) to its trithioate conversion product Def (Woodrow et al., 2018). Polycyclic aromatic
hydrocarbons (PAHs) such as dibenzanthracene that are released during
plant biomass burning are activated to epoxide forms that are prominent
mutagens and carcinogens (Chapter 4). But photoreactions of pesticides
in fog and air represents an area which warrants further work in terms of
mechanisms and rates.
Reactions of pesticides in air, as well as in moisture and particulate matter
in air, are not negligible and require considerations that must be studied by
companies during pesticide registration. Understanding these reactions has
led to discontinued use of some heavily used pesticides, and it helps understand the fate of pesticides and their long-range transport. The implications
of this are discussed more in Chapter 10.
3.6 Conclusions
No environmental compartment (water, soil, air, biota) exists in isolation.
After an intentional or accidental release, a chemical contaminant will be distributed to varying degrees among the various compartments, depending on
the properties of the chemical (organic content, water solubility, vapor pressure, diffusion coeffcient, BCF) and the environmental conditions. In these
different compartments, transformations may occur for reactive chemicals.
The concepts covered in this chapter should contribute to a better understanding of the environmental fate of chemical contaminants, leading to a
more confdent answer to the question “where did that chemical go?” Clearly
more work is needed, particularly on transformation of pesticides and other
contaminants, including viruses in air.
References
Angermann, J.E., Fellers, G.M., and Matsumura, F. (2002). Polychlorinated biphenyls and toxaphene in Pacifc tree frog tadpoles (Hyla regilla) from the
California Sierra Nevada, USA. Environ. Toxicol. Chem. 21(10), 2209–2215. DOI:
10.1002/etc.5620211027.