Pesticides, Organic Contaminants, and Pathogens in Air

Chemodynamics, Health Effects, Sampling, and Analysis

James N. Seiber, Thomas M. Cahill, Thomas A. Cahill

• Publisher: CRC Press
• Year: 2021
• Print ISBN:
  9780367485672
• Edition: 1
• eBook ISBN:
  9781000461725
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

The air is an important but largely unrecognized source of contaminant fate in the environment, including transport of pesticides and contaminants to nontarget areas and exposures for people and wildlife. This book summarizes and places in perspective the potential transport, transformation, and health implications of pesticides and contaminants in air, including the air we breathe. It delves into the hypothesis that the atmosphere is the most significant environmental compartment affecting the overall transport and fate of many classes of environmental contaminants.

The authors draw parallels between sampling, analysis, and impact of airborne toxics and particulate matter with the COVID-19 pandemic. Airborne viruses and fine particulate matter, which are of similar size, have remarkable parallels in how they are transmitted and accumulated in the respiratory tract.

FEATURES

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• Assesses exposures of people and wildlife to airborne chemicals

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• Includes case study applications, with relevant data summarized for pesticides and contaminants in air

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• Discusses approaches to modeling pesticides' and contaminants' dispersion and fate in air

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• Includes an assessment of the physicochemical properties of pesticides and contaminants that influence sampling and atmospheric mobility and fate

The authors are global experts in air contaminant research, and this book is well organized and helpful for people interested in regulatory, health, and other topics related to pesticides and contaminants in air.

James N. Seiber is a Professor Emeritus at the University of California, Davis.

Thomas M. Cahill is an Associate Professor in the School of Mathematical and Natural Sciences at Arizona State University.

1

Introduction: A Summary with New Perspectives

DOI: 10.1201/9781003217602-1

1.1 Introduction

Contaminants in air are responsible for more premature deaths worldwide than those in any other environmental media. The topic of air has never been more important in my (JNS) lifetime than it is now. In 2020, the world came to a virtual halt due to the novel coronavirus (COVID-19), an airborne virus that caused a pandemic. As of June 2021, 170 million people worldwide had been infected, and 3.5 million people died (600,000 people in the United States alone). As with other airborne contaminants, steps can be taken to lessen the effects. The first measure in many places was to stay home. And in the beginning as people shuttered up in their homes, animals took over abandoned cities and swimming pools became duck ponds. One potential upside of people staying home during the pandemic has been a sharp decrease in greenhouse gases (Plumer, 2021).

But much of the world has tried to return to daily life (whether or not it is premature is a contentious subject). To slow the spread, many strategies have been used in combination: masks that can filter virus-laden air, social distancing, vaccines, and virus-sniffing dogs. Although the vaccines were released with unprecedented speed and some are nearly 100% effective, the vaccination programs have been overwhelmed with logistical problems due to the challenge of vaccinating the entire population, vaccine shortages in some regions of the world, and vaccine hesitancy in some populations.

Also in 2020, weather and natural disaster events (due to global climate change) increased in duration and magnitude. California and the West Coast have experienced the worst wildfires in U.S. history, with more than 4 million acres of urban, farmland and forests being destroyed. Among the worst wildfires in California history, five were in 2020, and four of those were in August alone (CAL FIRE, 2021). Wildfires release particulate matter, CO₂, and incomplete combustion products that are known carcinogens (e.g., polycyclic aromatic hydrocarbons (PAHs)). And when pesticides and other applied chemicals are present, they are released to air.

It is urgent in this landscape to think and progress in a different way. Encouragingly, the new U.S. administration, sworn in January of 2021, is reinstating the United Sates into the Paris Agreement (an international effort to curb the generation of greenhouse gases) and banning new oil pipelines in Federal lands, signaling a renewed interest to improve the quality of air.

The implementation of FEW (food, energy, water) Nexus sustainability guidelines has progressed worldwide. The premise of the FEW Nexus is to consider the effects a technology developed for one sector will have on the other sectors. For example, a new farming technique that promises to feed more people must also consider the impacts it will have on water and energy usage. In line with FEW Nexus principles, biopesticides and more robust crops (both genetically engineered and traditionally bred) show promise for future reductions in the environmental impact of agriculture. Most of the new pesticides registered in the United States are biopesticides, and China has set policies to encourage development and adoption of biopesticides and sustainable practices in its vast farming activities (Figure 1.1). However, in order to feed the world’s growing population, especially those in economically developing nations like China, it is projected that use of synthetic pesticides will increase substantially before biopesticides and complementary farming practices that reduce the use of synthetic pesticides become the norm.

FIGURE 1.1
Agricultural regions of China. (Image credit: U.S. Central Intelligence Agency.)

This book is a compendium of over 30 years of research addressing contaminants in the air. Our work initiated and paved the way for being able to examine the quality of ambient air by identifying and quantifying its contaminants, leading to comprehensive understanding of transport, fate, and exposure of pesticides and toxics in air. It is a product of over three decades of research, teaching, and outreach by our group and our cohorts at the University of California, Davis; the University of Nevada, Reno; the United States Department of Agriculture–Agricultural Research Service (USDA-ARS); and Arizona State University dating roughly from 1970 to 2010. Most of the original research was in collaboration with scientists and agency personnel and has subsequently been published in peer-reviewed papers, reviews, book chapters, dissertations, reports, and forums such as American Chemical Society (ACS) symposia and other national and international venues.

1.2 Distribution and Fate of Pesticides in Air

It all started with a simple question: where do all the chemicals released into the environment go? Some argued for water drainage to streams, ponds, lakes, and oceans. Others for soil breakdown. Yet no one knew for certain. We postulated air and transformation to be the missing elements. Chemicals emitted directly to air, or those that volatilize slowly into air, break down and become diluted in the huge volume of air and “disappear.” Simple, right? Not hardly. The complexity is evident when one views all the possibilities (Figure 1.2).

FIGURE 1.2
Pesticide cycling in the environment. (Reproduced from Author Unknown (1974) Scientists probe pesticide dynamics. Chem. Eng. News Archive 52, 32–33. Copyright (1974) American Chemical Society).

Among the pollution caused by the industrial revolution, air pollution was most striking. Shift from coal and regulations put into place in the developed world have drastically improved air quality in developed countries. As discussed in Chapter 4, regulations by the U.S. Environmental Protection Agency (EPA) and various state and local municipalities have improved the quality of air in the United States (similar measures were successful in other developed regions as well) (Landrigan et al., 2018). While conditions in developed regions are improving, rapidly industrializing nations today are experiencing decreasing air quality (Landrigan et al., 2018). Initiatives to shift biomass burning to biofuel production in developing nations, especially in Asia, may change this in the coming years. In 2016, of the 9 million premature deaths caused by pollution, 6.5 million are estimated to be from airborne pollution.

Pesticides have been intentionally released to the environment for economic reasons at higher rates than any other class of chemicals (Woodrow et al., 2018). There is much we do not know about the biological consequences of low levels of pesticides and other toxics in ambient air. Our research, plus the research of others, over the past 30 years has made it clear that the atmosphere is not an “infinite reservoir” and that pesticides and other toxics released to air do not simply go away (Woodrow et al., 2018). As described in depth in Chapter 10, long-range transport, as measured by transect studies, occurs with pesticides. While stable and nonpolar pesticides might be found in low levels in air and water in remote locations, they have a tendency to bioaccumulate to high levels, especially in higher trophic level organisms. Until about that time (30 years ago), the fate of pesticides released to the environment was not considered for their impact on human and ecosystem health. The tipping point was the public awareness brought about by Rachel Carson’s book, Silent Spring in 1962 (Carson, 1962). Eventually, it led to the ban of DDT and other pesticides and the creation of the U.S. EPA in 1970.

We all experience air in different ways—as a means to sustain and refresh ourselves, to catch our breath, and to sense aromas and odors in our surroundings. Air is also the medium through which we see our surroundings. We inhale and exhale on average a liter per minute which can expose us to air’s contents. There is more to air besides oxygen, nitrogen, and carbon dioxide. Think of fresh air compared to polluted air, containing odors from perfumes, freshly baked bread, refineries, chemical complexes, auto exhaust, skunks, and cattle feedlots. This bouquet of odors is due to a complex chemical mixture. New chemists in industry are told the odor from manufacturing was the smell of money! Over time they realized it was pollution and potentially harmful.

Odor is not, however, the only indicator of chemicals in air. Think also about insect pheromones that are emitted in femtogram quantities to attract male moths to females and the spray from a crop duster that kills pests or the lethal Great Smog events during early industrialization.

Air is also a transport and exposure route for actual and potential exposures to people, e.g., within the current pandemic of COVID-19, valley...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Acknowledgments
• Authors
• List of Abbreviations
• Glossary of Agencies
• Glossary of Terms
• 1. Introduction: A Summary with New Perspectives
• 2. Historical and Current Uses of Pesticides
• 3. Physical and Chemical Properties of Pesticides and Other Contaminants: Volatilization, Adsorption, Environmental Distribution, and Reactivity
• 4. Pesticide Exposure and Impact on Humans and Ecosystems
• 5. Environmental Fate Models, with Emphasis on Those Applicable to Air
• 6. Sampling and Analysis
• 7. Pesticides in Fog
• 8. Fumigants
• 9. Trifluoroacetic Acid from CFC Replacements: An Atmospheric Toxicant Becomes a Terrestrial Problem
• 10. Drift
• 11. Viruses, Pathogens, and Other Contaminants
• 12. Biopesticides and the Toolbox Approach to Pest Management
• 13. Conclusions
• Index