13
Conclusions
13.1 Conclusions
Pesticides are omni present in the environment and the major source is agricultural activities. Half or more of the chemicals released during pesticide
application enter the air. Application and all other steps—plowing/tilling,
irrigation, planting, harvesting, and agricultural residue combustion (a waning agricultural practice, banned in some places) —release vapors, dust,
smoke, and particulate matter that contain pesticides and other by-products
of combustion (e.g., PAHs, dioxins, and others). These forms of release, as
well as those due to manufacturing of pesticides and waste disposal, are relatively predictable and manageable and thus give us a start on accounting for
pesticides in the environment.
However, unexpected accidental spills and natural disasters often result in
environmental and health catastrophes. For example, following the industrial
accidental release of methyl isocyanate at Bhopal, India, killed an estimated
20,000 people and exposed another 200,000, and a railroad derailment near
Mount Shasta dumped methyl isothiocyanate into the Sacramento River, killing trout, salmon, and other fsh. Wildfres, another source of pesticides and
combustion products in the environment, have become more prevalent due
to global climate change. In 2020, the worst wildfres in U.S. history burned
vast expanses of urban, agricultural, and forest land in California and along
the west coast.
Multiple factors cause pesticides to reach unintended sources. The environmental mobility of pesticides, including their presence in air, is largely
dictated by the physicochemical properties of the pesticide active ingredients
and its formulation ingredients—vapor pressure (most important), solubility,
adsorption, and reactivity. Initial deposits, or residues from application, can
become mobilized by tillage, irrigation, and a myriad of human activities
in the immediate area of use and remote areas (depending on climatic and
topographical features). Mass transport (via wind and erosion) and atmospheric deposition (rain, fog, and dry deposition) also determine how much
pesticide is in the air. The manmade problem of global climate change that
increases the temperature and severity of weather events further magnifes
DOI: 10.1201/9781003217602-13
215
Conclusions
13.1 Conclusions
Pesticides are omni present in the environment and the major source is agricultural activities. Half or more of the chemicals released during pesticide
application enter the air. Application and all other steps—plowing/tilling,
irrigation, planting, harvesting, and agricultural residue combustion (a waning agricultural practice, banned in some places) —release vapors, dust,
smoke, and particulate matter that contain pesticides and other by-products
of combustion (e.g., PAHs, dioxins, and others). These forms of release, as
well as those due to manufacturing of pesticides and waste disposal, are relatively predictable and manageable and thus give us a start on accounting for
pesticides in the environment.
However, unexpected accidental spills and natural disasters often result in
environmental and health catastrophes. For example, following the industrial
accidental release of methyl isocyanate at Bhopal, India, killed an estimated
20,000 people and exposed another 200,000, and a railroad derailment near
Mount Shasta dumped methyl isothiocyanate into the Sacramento River, killing trout, salmon, and other fsh. Wildfres, another source of pesticides and
combustion products in the environment, have become more prevalent due
to global climate change. In 2020, the worst wildfres in U.S. history burned
vast expanses of urban, agricultural, and forest land in California and along
the west coast.
Multiple factors cause pesticides to reach unintended sources. The environmental mobility of pesticides, including their presence in air, is largely
dictated by the physicochemical properties of the pesticide active ingredients
and its formulation ingredients—vapor pressure (most important), solubility,
adsorption, and reactivity. Initial deposits, or residues from application, can
become mobilized by tillage, irrigation, and a myriad of human activities
in the immediate area of use and remote areas (depending on climatic and
topographical features). Mass transport (via wind and erosion) and atmospheric deposition (rain, fog, and dry deposition) also determine how much
pesticide is in the air. The manmade problem of global climate change that
increases the temperature and severity of weather events further magnifes
DOI: 10.1201/9781003217602-13
215