Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 27
2
Challenges of the 21st Century
Efforts of the US Environmental Protection Agency (EPA) to address en-
vironmental degradation over the last 40 years have had some marked successes,
including reductions in particulate and sulfur air pollution, reductions in indus-
trial discharges in waterways, and removal of lead from gasoline. Yet enormous
challenges remain. Although many of the more visible environmental problems
have been at least partly addressed, persistent problems and new problems affect
the environment's ability to provide the ecosystem services on which humans
and other living organisms depend.
Solving current environmental challenges--for example, nutrient overload
and eutrophication, climate change, increased body burdens of diverse chemi-
cals, and water-quality declines--requires understanding the nature of the prob-
lems and their relationships to other phenomena. In particular, solving environ-
mental challenges requires consideration of root causes and possible unintended
consequences of interventions in domains not normally considered. Developing
a strong understanding of how various key drivers can affect multiple phenom-
ena relies on the expansive application of systems thinking. Identifying viable
and sustainable solutions that will optimize economic, social, and environmental
benefits should have high priority. Ensuring that EPA has the scientific capacity
to promote those solutions requires a science strategy that builds on accom-
plishments but includes innovative and diverse tools.
Current and future environmental challenges also include disasters, which
require EPA to have an ability to respond quickly to address environmental con-
sequences. Those disasters can arise from natural events such as storms, earth-
quakes, and volcanic eruptions; from accidents at major industrial facilities, such
as pipelines, large bulk-storage facilities, mines and wells, and power and
chemical plants; or as the direct or indirect consequence of terrorism events.
EPA is and will continue to be responsible for monitoring and addressing the
environmental changes resulting from disasters (whether natural or human-
caused).
27
OCR for page 28
28 Science For Environmental Protection: The Road Ahead
Chapter 2 discusses major factors that lead to environmental change and
some of the persistent challenges that EPA will likely continue to face in the
coming decades. The committee cannot predict with certainty what new envi-
ronmental problems EPA will face in the next 10 years or more, but it can iden-
tify some of the common drivers and common characteristics of problems. The
specific topics discussed in this chapter were identified based on committee ex-
pertise and a review of the scientific literature. This chapter is not meant to be an
exhaustive list of all factors leading to environmental changes or of all persistent
and future environmental challenges. Instead, the chapter is meant to provide
some illustrative examples of the types of problems facing EPA today and some
of the factors that create and influence those problems.
MAJOR FACTORS LEADING TO ENVIRONMENTAL CHANGE
Major socioeconomic factors are directly and indirectly driving environ-
mental changes and are increasing the imperative for EPA to maintain and
strengthen its environmental research efforts. Those socioeconomic factors are
often reflected in population growth and migration, demographic shifts, land-use
change and habitat loss, increasing energy demand and shifting energy supplies,
new consumer technologies and consumption patterns, increasing emissions of
greenhouse gases, and movement of organisms beyond their traditional ranges,
which in turn have implications for the scientific knowledge that is required to
inform policy decisions at EPA effectively. EPA will be challenged in coming
years to adapt to rapid changes in scientific knowledge, society, and the envi-
ronment. An increased awareness of the effects of human activity on human
health and the environment has raised people's concern regarding the issues that
the agency is charged with addressing.
Population Growth
It took until 1800 AD for mankind to reach a population of 1 billion peo-
ple, but only required 123 more years to reach 2 billion, 33 more years to reach
3 billion, and about 1314 more years for each additional billion people thereaf-
ter (UN 1999). In October 2011, the worldwide population hit 7 billion (UN
2011). With the dramatic increase in population, human activities have altered
and will continue to alter an ever-increasing portion of Earth's surface (Wulder
et al. 2012). Such activities have diminished natural ecosystems and the benefits
that they provide, including water purification, flood control, climate modera-
tion, and new crop plants.
In the United States, the population continues to increase at approximately
1% per year (US Census Bureau 2012). This population growth contributes to
such environmental effects as increased emissions of greenhouse gases due to
energy use, transportation demand, and residential and commercial activities
(EPA 2011a); increased consumption of resources (Worldwatch Institute 2011);
OCR for page 29
Challenges of the 21st Century 29
increasing numbers of manufactured chemicals and products introduced into the
environment (EPA 2011a); and increased food and water demand and concomi-
tant changes in land use (NRC 2011). Those demographic, consumption, and
production changes contribute to the challenge of addressing environmental
problems and health outcomes as increasing amounts of land and resources are
demanded to meet human wants and needs.
Changes in Land Use
Land use is a major factor driving environmental quality. Land use
strongly influences water quality through runoff, water quantity through influ-
ence on the hydrologic cycle, air quality through emissions and deposition and
carbon storage in terrestrial landscapes, and biologic diversity through habitat
loss, disturbance, and resource availability. In the United States, changes in land
use result largely from expansion of urban and agricultural areas, energy devel-
opment, and changes in forestry practices.
Population growth and demographic transitions have increased the re-
quirement of land area for residential, commercial, and transportation activities
(Squires 2002). In the conterminous United States, it has been estimated that up
to 45.5 million acres (2.4%) of land is characterized by impervious surfaces (in-
cluding roads, building, sidewalks, and parking lots) (Nowak and Greenfield
2012). Impervious surfaces change the hydrology and ecology of rivers (higher
peak flows and scouring of habitat) and reduce the availability of groundwater
for agriculture and other human use. In addition, the interconnected effects of
urban sprawl are numerous and complex--greater automobile use in less-
densely populated communities can lead to increased air pollution and more
sedentary lifestyles, both of which are risk factors for heart disease. Less dense
housing also increases energy use per capita and contributes to increased air
pollution and climate change and potentially to such adverse health effects as
increased asthmatic attacks (Frumkin 2002; Younger et al. 2008; Brownstone
and Golob 2009).
Despite increased demand for food and fuel, the land area dedicated to ag-
riculture has not increased substantially over the last few decades. In the United
States, acreage devoted to corn has increased over the last 10 years, but total
agricultural acreage has been largely unchanged. Agricultural productivity has
increased as a result of major investments in research by both the public and
private sectors, but there is still uncertainty as to whether the increase can be
maintained and, if so, whether it would have associated environmental costs. For
example, without substantially increased nutrient-use efficiency, increased
amounts of fertilizers will be applied per acre of agricultural land, and therefore
increased amounts of those nutrients will be lost to the environment. If increased
productivity is not maintained, more acres will need to be devoted to agriculture,
probably at the expense of marginally productive lands and natural ecosystems.
OCR for page 30
30 Science For Environmental Protection: The Road Ahead
Increased demand for bioenergy, wind, and solar-power plants may also
place additional pressure on land resources. Beyond ethanol-based biofuels,
much of the bioenergy used in power generation is likely to come from forest
biomass through increased use of harvesting residues and (potentially) increased
harvesting. Forest ownership patterns have shifted over the last 20 years as a
result of the large-scale disaggregation of the forest-products industry. That shift
has increased land-use decisions that are based on maximizing shorter-term eco-
nomic returns rather than long-term production of forest products (USDA 2006).
When combined with more intensive use of forests to meet the demand for a
shifting basket of products (largely bioenergy), shifts in forest ownership may
have increasing effects on the environment. Thus, to pursue its environmental-
protection mission effectively in coming years, EPA will need to expand its ef-
forts to monitor and understand land-use changes.
Energy Choices
Energy choices in the United States--including bioenergy, conventional
and unconventional oil and gas production, coal, and nuclear power--all have
important implications for the environment through the effects of resource ex-
traction or production, fuel combustion, and waste discharge or disposal. The
April 2010 blowout of British Petroleum's Macondo deepwater oil well illus-
trated how devastating the unintended consequences of energy development can
be; the accident killed 11 workers and led to the largest oil spill in US history
and the closure of some fisheries in more than 80,000 square miles of the Gulf
of Mexico (NOAA 2012a). The rapid but less dramatic expansion of natural-gas
production across the United States has raised concerns about effects on local
water and air quality. There are also concerns about greenhouse-gas emissions
associated with methane leakage during production and transport, although natu-
ral gas is recognized as a fuel that inherently emits less greenhouse gas (about
half) than coal when combusted (Jaramillo et al. 2007). The comparative advan-
tages are lost at higher leak rates (that is, the rate at which methane, the primary
constituent of natural gas, is lost to the atmosphere during the production, trans-
portation, and use of natural gas) (Alvarez et al. 2012).
Another example is the production of ethanol for use as a biofuel, which
has increased rapidly in the last decade because of the desire for energy security
and renewable transportation fuels. In 2010, about 40% of US corn production
was used as feedstock for biofuel production (NRC 2011). Such agricultural and
energy choice practices can have negative environmental effects; increased pro-
duction of corn as an ethanol feedstock has resulted in increased nutrient runoff
and corresponding eutrophication of coastal waters, including the Gulf of Mex-
ico (NRC 2008, 2011). Given current water-use efficiencies, large quantities of
water are also required for irrigation and the intensification of agricultural prac-
tices can increase erosion (NRC 2008, 2011). Further research is required to
develop new perennial feedstocks that would require less tillage and have high
OCR for page 31
Challenges of the 21st Century 31
nutrient-use efficiencies so that soils and nutrients would be held in place. Ulti-
mately, competition between the demand for food and the demand for land
needed for other purposes will limit the amount of biofuels that can be produced.
The extent to which new technology can alleviate those constraints is unclear
because of limitations in photosynthetic efficiency. An improved understanding
at EPA of the potential effects of new energy options and emerging technologies
would help ensure that they are pursued in ways that protect the environment
and human health. Broadly, the domain of energy is a classic example where
systems thinking would be needed, as technologic or regulatory changes influ-
encing one fuel type can have ripple effects across the life cycle of multiple fu-
els. For example, emissions requirements on power plants could reduce air pol-
lutant emissions from coal-fired power plants and decrease impacts related to
coal mining and transport, but could lead to increased use of natural gas and
hydrofracturing as an extraction technology. Systems-level analyses that take
account of these ripple effects and determine the net implications for ecologic
and human populations are crucial.
Technologic Change and Changing Consumption
Technologic innovation creates a large challenge to acquiring the envi-
ronmental data required to inform policy in a timely way. In the last 2 decades, a
revolution in electronics has led to such devices as cellular telephones, iPods,
and tablet computers. In 1980, the computer-chip industry used only 11 ele-
ments from the rare earth and platinum series metals; today it requires 60 ele-
ments, or almost two-thirds of the natural periodic table (Schmitz and Graedel
2010; Erdmann and Graedel 2011). Such technologic change not only requires
increasing production but challenges the ability of industry to recycle and re-
cover the (sometimes toxic) materials used in electronic devices. EPA is chal-
lenged to assimilate or perform research fast enough to understand the health
and environmental risks associated with the production and disposal of those
devices, let alone how to mitigate any risks. A legacy of contaminated soils in
both terrestrial and aquatic environments is a reminder that managing these
technologic challenges is not new. Increased vigilance is necessary to ensure
that future generations are not left with a legacy of contamination as has hap-
pened in the past.
Other innovative technologies--such as new chemicals, nanomaterials,
and synthetic biology--are important for economic growth. However, they also
require focused research to understand adverse human health and environmental
effects and to understand how to avoid harmful effects through safe product
design and to ensure that wastes are reused or recycled. In the face of rapid
technologic innovation, a key challenge for EPA is acquiring the scientific data
required to fulfill its mission of protecting human health and the environment
without imposing a drag on economic development (see Chapter 4). Understand-
ing how new technologies will influence the application and use of existing
OCR for page 32
32 Science For Environmental Protection: The Road Ahead
technologies will be important in ensuring the net benefit of EPA's efforts. So-
cial-science and behavioral-science research will be critical in helping to design
and evaluate strategies for meeting that challenge.
Transport of Organisms
The geologically recent evolution of life occurred on isolated continents,
each of which evolved a distinctive biota. However, the ever-expanding move-
ment of people and goods has tended to homogenize Earth's biota and resulted
in two increasingly serious environmental problems: the spread of animal-
vectored diseases and the invasion of exotic species. Species are transported
around the world inadvertently on ships, airplanes, and automobiles. Others are
deliberately imported for agriculture, horticulture, biologic control, and recrea-
tion (such as pets or game animals). Most do not become established in the loca-
tions to which they are introduced, and few of the ones that do naturalize disrupt
the local ecologic communities seriously. However, some do become highly
invasive, dominating ecologic communities, spreading diseases, and diminishing
the ability of other species to survive. One example is the impact zebra mussels
have had in the Great Lakes region (Pejchar and Mooney 2009). Zebra mussles
compete with some fish for zooplankton prey, clog intake pipes and impair flow
at water treatment plants, contribute to the bioaccumulation of mercury and lead,
and change nutrient balances in the water resulting in increased phytoplankton
and cyanobacterial blooms. Few studies have been done to try to estimate the
total costs of nonnative invading species at a national level; however, one study
estimates that about $120 billion is spent in the United States per year due to
environmental damages and losses caused by nonnative invading species (Pi-
mentel et al. 2005; Pejchar and Mooney 2009). Increasingly, people are intro-
duced to new exposure pathways and vectors through other animals that are po-
tential carriers of diseases to which humans and other animals lack immunity.
ENVIRONMENTAL AND HUMAN HEALTH CHALLENGES
The patterns of change briefly described above have resulted in a suite of
current and emerging environmental and human health challenges for EPA, such
as
Human and environmental exposure to increasing numbers, concentra-
tions, and types of chemicals. Factors contributing to human and environmental
exposures include energy choices, technologic change, and changing energy
consumption.
Threat of deteriorating air quality through changes in weather (Jacob
and Winner 2009) and through the formation of more particles in the atmosphere
from allergens, mold spores, pollen, and reactions of primary air pollutants
OCR for page 33
Challenges of the 21st Century 33
(Confalonieri et al. 2007). Factors contributing to deteriorating air quality in-
clude population growth, energy choices, changing consumption, and climate
change.
Water quality and coastal-system degradation, including challenges to
rebuild old infrastructure and address such issues as urban stormwater and by-
pass of raw sewage (NOAA 2012b). Factors contributing to water quality and
coastal-system degradation include land use, urban sprawl, climate change, and
energy systems.
Nonpoint-source pollution and nutrient effects associated with agricul-
tural runoff of nutrients and soils. Factors contributing to nonpoint-source pol-
lution and nutrient effects include climate change, land use, and technologic
change (NRC 2011).
Expanding quantities of waste with a wider array of component materi-
als (Schmitz and Graedel 2010). Factors contributing to expanding quantities of
waste include population growth, energy usage, technologic change, and chang-
ing consumption.
Expanding ecologic disruptions (USDA 2012). Factors contributing to
ecologic disruptions include population growth, land use, climate change, and
transport of organisms.
The first three of the challenges listed above are discussed in greater detail
below, with some examples that illustrate the need for a better approach for ac-
cessing, obtaining, developing, and using science and engineering in the pursuit
of environmental solutions. In addition, an overarching challenge relates to the
ever expanding spatial and temporal scales at which many of these challenges
operate. Although the challenges in this chapter are only illustrative of today's
challenges and although it is difficult to predict what emerging challenges will
dominate in the future and what global implications will arise from local-scale
environmental drivers, it is quite likely that future emerging challenges will
share key features of the examples below. Some of those key features include
complex feedback loops, the need to understand the effects of low-level expo-
sures to numerous stressors rather than high-level exposures to individual stress-
ors, and the need for systems thinking to devise optimal solutions.
Chemical Exposures, Human Health, and the Environment
Human health is inextricably linked with ecosystems and the quality of the
environment. Since the beginnings of the discipline of public health, it has been
recognized that most diseases are influenced by three factors: the agent (chemical,
biologic, or physical), the host (genetic or behavioral), and the environment
(physical or social). Historically, the greatest advances in controlling infectious
diseases have been based on environmental improvements, such as improvements
in water quality, sewage treatment, and food protection. Controlling chemical ex-
OCR for page 34
34 Science For Environmental Protection: The Road Ahead
posures and reducing or preventing associated health effects can be more challeng-
ing.
Although new chemicals continue to be created and enter the environment,
many of the problems they cause are not new. Cancer was among the dominant
health concerns through the early decades of EPA. Carcinogenic pollutants--
including asbestos, arsenic, benzene, hexavalent chromium, dioxin, and vinyl
chloride--were a major focus of interest in human health effects because of both
public concerns and expanded toxicologic and epidemiologic findings. Identify-
ing and controlling carcinogens was a dominant driver of EPA science, from
analytic chemistry through toxicity testing and risk assessment. While cancer
will continue to be an EPA and societal priority, other health outcomes are likely
to receive increasing attention given growing epidemiologic and toxicologic
evidence. Many of these health effects are chronic and subtle, and there is still
much to be learned. For example, hormonally active chemicals have long been
researched, but the importance of their potential health effects continues to be
elucidated. A new class of hormonally active substances receiving increased
attention are obesogens, which target lipid metabolism and may interfere with
natural hormone signaling (Kirchner et al. 2010).
Another challenge related to exposure to chemicals or other stressors is
characterizing susceptibility to adverse health effects. Susceptibility can vary
greatly in a population as a function of factors that are not often systematically
evaluated. Young children may be at greater risk for neurologic and endocrine
effects, and the elderly may be more susceptible to immune effects, cardiovascu-
lar effects, or infection. Race or socioeconomic status may increase the risk of
cumulative environmental effects that result from living disproportionally closer
to pollution sources (Bullard 2000). Poverty, stress, and lack of access to medi-
cal care decrease human resilience and the ability to adapt; disadvantaged com-
munities are at increased risk when faced with increased exposure. Genetic fac-
tors also influence susceptibility and underscore the importance of gene
environment interaction in determining health outcomes.
Transgenerational effects and sensitive populations are also of great con-
cern for public health. Exposure to chemicals and other stressors during gesta-
tion can affect the mother, the fetus, and even the germ cells of the fetus and
lead to effects on the third generation (Holloway et al. 2007). Some research
indicates that chemical exposure in the womb can trigger epigenetic changes
much later in life. Adipose-tissue development, food intake, and lipid metabo-
lism may be altered as a result of exposure to organotins, perfluorooctanoic acid,
diisobutyl phthalate, bisphenol A, and other xenobiotic chemicals found in the
environment (Grun and Blumberg 2006). The epidemic of obesity, diabetes, and
metabolic syndrome in the United States and elsewhere indicates that research is
needed to determine whether there is a causal link to the chemicals described
above at concentrations measured in the environment. If environmental expo-
sures caused even a tiny fraction of the almost 130% increase in obesity in the
United States over the last 40 years (Wang and Beydoun 2007), they constitute
an important emerging challenge for EPA science and regulation.
OCR for page 35
Challenges of the 21st Century 35
An area of increasing recognition is that of cumulative effects from the
built and social environment on health and well-being. Multiple exposures and
social factors can interact to increase risks and affect community health status.
The role of the built environment in community health is analogous to the role
of habitat change in ecologic quality. Effective environmental protection takes
into consideration all environments that are valuable to humans and natural sys-
tems, and EPA can continue to have significant impacts in this area of research.
Today and in the future, EPA will be challenged to maintain and consider
an expanding list of chemicals and potential adverse environmental health ef-
fects. Because people are being exposed to many different types of stressors that
may interact antagonistically or synergistically and because chemicals can affect
different populations in different ways, EPA will also be challenged to refine
methods to evaluate cumulative effects (EPA 2011b). New approaches to under-
standing and managing risks and to measuring health outcomes would support
more informed environmental-policy decisions.
Biomonitoring and Emerging Concerns about Exposure and Health
Biomonitoring for human exposure to chemicals in the environment has
provided a new lens for understanding population exposures to toxicants. The
Fourth National Report on Human Exposure to Environmental Chemicals
measured 212 chemicals in the US population, including 75 for the first time
(CDC 2009). The results indicated some declining loads of historical pollutants,
such as lead and polychlorinated biphenyls, but also indicated widespread popu-
lation exposure to previously unmeasured and potentially toxic chemicals. For
example, bisphenol A, which potentially has reproductive and endocrine effects,
was found in the urine of over 90% of those sampled. Bioaccumulated polybro-
minated diphenyl ethers were found in the serum of almost the entire population,
as were several polyfluorinated compounds used to impart nonstick characteris-
tics to surfaces. The report also provided improved data on pervasive exposures
to historically recognized toxicants, such as arsenic and mercury.
The "exposome" is a measure of all exposures that a person accrues in a
lifetime (see Chapter 3). It is exceedingly difficult to measure all exposures that
a person accrues in a lifetime because of the enormous variability in exposure
over space and time and to an ever-changing set of chemicals that are used by
society. Measuring such exposures in an entire population is even more difficult.
Yet the exposome is a useful concept that will be increasingly important in com-
ing years and allow the exploration of the progression of disease from an ab-
sorbed dose to a targeted health outcome, including the influence of genetic in-
formation on susceptibility and biomarkers.
Novel understanding of population exposure brings new challenges for envi-
ronmental health science. The report Biomonitoring for Environmental Chemicals
(NRC 2006) indicates the analytic methods for detecting exposures have outpaced
the science of interpreting the potential implications for human health. As the list
of biomarkers grows, EPA will face constant challenges to interpret health and
OCR for page 36
36 Science For Environmental Protection: The Road Ahead
ecologic implications, identify sources of exposure, and trace the pathways of hu-
man exposure. In addition to the traditional single-substance approach, the recog-
nition that the population is chronically exposed to low concentrations of large
numbers of pollutants will necessitate new methods for understanding cumulative
effects of multiple contaminants on health.
Air Pollution and Climate Change
EPA's first goal in its 20112015 strategic plan is "taking action on cli-
mate change and improving air quality" (EPA 2010a). This goal encompasses
mandates under the Clean Air Act and other statutes, obligations under interna-
tional treaties and agreements, and executive branch commitments. The follow-
ing sections provide examples of challenges associated with understanding and
addressing air pollution and climate change.
Improving Air Quality
The Clean Air Act is designed primarily to address effects on human
health and welfare (including visibility and ecologic effects) that are due to pol-
lutants released into or produced in the ambient atmosphere. That is accom-
plished through regulations that limit emissions from a broad array of sources--
feedlots, ship engines, petroleum refineries, power plants, vehicles, and more.
The act requires EPA to protect human health and welfare through provisions
that specifically address a core set of six criteria air pollutants, nearly 200 listed
hazardous air pollutants, acid deposition, and protection of the stratospheric
ozone layer (42 USC [2008]). It also directs the EPA administrator to regulate
other air pollutants on finding they may reasonably be expected to endanger
public health and welfare. The Clean Air Act and other statutory mandates give
rise to the need for improved scientific and technical information on health ef-
fects, human exposures, ecologic exposures and effects, ambient and emission
monitoring techniques, atmospheric chemistry and physics, and pollution-
prevention and emission-control methods for hundreds of pollutants.
Beyond the outdoor air-quality focus under the Clean Air Act, some pro-
grams are designed to address indoor air quality. Many Americans spend 65% to
over 90% of their time indoors (Allen et al. 2007; Wallace and Ott 2011). Expo-
sures to certain pollutants released from building materials and consumer prod-
ucts are often substantially greater indoors than outdoors (Hoskins 2011). EPA
has extensive authority over chemicals and microbial agents found or used in the
indoor environment under environmental laws including the Toxic Substances
Control Act and the Federal Insecticide, Fungicide, and Rodenticide Act. It also
sets the guideline for acceptable levels of radon in indoor air. EPA is a leader in
understanding the dynamics of vapor intrusion from soil gas into buildings and it
conducts research on human exposure in the indoor environment and corre-
sponding health effects (EPA 2005, 2011c, 2012a,b,c).
OCR for page 37
Challenges of the 21st Century 37
The agency's efforts to improve air quality continue to have high priority
despite decades of progress because the economic costs that air pollution im-
poses on society remain high. For example, Hidden Costs of Energy: Unpriced
Consequences of Energy Production and Use (NRC 2010) estimated that the
aggregate damages in the United States associated with air pollution from the
country's coal-fired power plants were at least $62 billion in 2005 and that air
pollution from motor vehicles contributed at least another $56 billion in dam-
ages. The Clean Air Act is an expensive law in terms of compliance, but it still
has a highly positive benefit-to-cost ratio (EPA 2011d). EPA recently issued a
report called The Benefits and Costs of the Clean Air Act from 1990 to 2020
(EPA 2011d). According to that study, the direct benefits from the 1990 Clean
Air Act amendments are estimated to be almost $2 trillion by the year 2020,
exceeding costs by a factor of more than 30 to 1.
Impacts of Climate Change
In the last several decades, it has become clear that human activities have
had substantial effects on global climate. The global temperature has increased
by an average of 0.6oC since 1901 (IPCC 2007) and variability has increased as
well, especially in patterns of precipitation and runoff. That pattern led Milly et
al. (2008) to conclude that "stationarity is dead" 1 in the context of water-
resource management and to suggest that a new paradigm is needed for dealing
with the fact that human society can no longer count on the conformity of mean
precipitation--or even variability in annual precipitation--to historic patterns.
Many climatologists, while concerned about the increase in mean global tem-
perature, are focused on the changes in extreme temperatures and precipitation
(such as floods and droughts) because the extremes cause greater social and eco-
logic disruption than a shift in average temperatures. Climate change may be the
most obvious example of the need for systems thinking in policy-making, given
complex interactions between regional air quality and climate change and the
numerous pathways by which the environment and human health can be influ-
enced. Many of the factors discussed earlier in this chapter will have direct and
indirect influences on climate change, which will itself influence land use pat-
terns and other drivers.
There is evidence that the climate change that has occurred in recent dec-
ades has made it harder and more expensive to address air-quality problems
(see, for example, Bloomer et al. 2009 and IWGSCC 2010). Furthermore, there
is strong scientific consensus that in coming decades climate change is likely to
increase the frequency of heat waves, exacerbate problems with water supply
and water quality, increase the severity of storms, and disrupt ecosystems, habi-
1
Stationarity is the term used when statistics (such as mean, median, variance) are
constant through time.
OCR for page 43
Challenges of the 21st Century 43
Excess nutrients reach surface-water resources in direct discharges from
point sources (for example, municipal wastewater-treatment plants) and from
diffuse nonpoint sources (for example, nutrient runoff from farmland, urban,
and suburban areas and air pollution). Because the nutrient-use efficiency of
crops is less than 100%, farmers need to apply more nutrients to their fields than
the plants need for healthy growth. The challenge for all farmers is to add fertil-
izer at the optimal time and rate and then to keep the nutrients in the field. Con-
comitant with the substantial increases in agronomic yields that have allowed
agriculture and fish production to meet the food needs of 7 billion people has
been a need for higher rates of application of fertilizers, which have exacerbated
runoff, limited the effectiveness of strategies for remediating eutrophication, and
resulted in production of nitrous oxide as a byproduct of nitrification and denitri-
fication processes. (Nutrient sources for the Chesapeake Bay and the Gulf of
Mexico are shown in Figure 2-1.) Addressing the nutrient loading will require
increased scientific understanding, including new information on pollution
sources, on emerging technologies that could be used in agriculture and in
wastewater treatment, on water quality conditions, and on the response of eco-
systems to increasing nutrient loads and shifting stochiometry. Such scientific
understanding can be gained only through integrated research.
The Chesapeake Bay, North America's largest estuary, offers a highly
instructive example of contributions made by EPA and allied researchers to a
more fundamental understanding of the physical processes that lead to the ef-
fects of nutrient pollution. Substantial reductions in nutrient discharges from
sewage-treatment plants, factories, and other point sources of pollution have
been achieved in the bay watershed since the 1970s but are insufficient to
meet water-quality goals. The challenges faced by the Chesapeake Bay eco-
system are shared by many other ecosystems, but the differences among them
make the required research and the effective tools for addressing the chal-
lenges more complex. For example, 500 km to the north of the Chesapeake
Bay lies Narragansett Bay. Although smaller than its southern cousin, it shares
many historical and ecologic characteristics; but the challenges faced today by
the Narragansett Bay (where EPA's Atlantic Ecology Division Laboratory is
located) have developed in very different ways. The region has historically
been dominated by agricultural activity, but that is no longer the case. Today,
Narragansett Bay suffers from excess nitrogen inputs, largely from upstream
wastewater-treatment facilities (Pryor et al. 2007). The upper reaches of the
bay have been closed to shellfishing and swimming for decades. In 2004,
Rhode Island mandated a minimum standard for effluent nitrogen from the
wastewater facilities within its jurisdiction, yet the science suggests that with-
out concomitant reductions in nitrogen from wastewater facilities upstream on
the Blackstone River in Massachusetts and reduction in nitrogen inputs that
result directly and indirectly from air pollution, restoring the waters of the
upper bay will be difficult (see Figure 2-2). Narragansett Bay, as a result of
the large influence of sewered effluents, should be one of the easiest places to
OCR for page 44
44 Science For Environmental Protection: The Road Ahead
address chronic water-quality deterioration, but it has proved elusive even
there.
Nutrient (nitrogen and phosphorus) pollution is one of the more persistent
and pervasive environmental problems in the United States, and it is worsening in
many locations (Howarth 2008). The volume of nutrients reaching surface water
and groundwater has increased substantially since the middle of the 20th century
as a result of a complex of factors, including population growth, changes in land
cover, increased fossil fuel combustion, and changes in the structure of agricultural
production (Selman et al. 2008). Providing the scientific foundations for the de-
velopment of policies that can reduce nutrient-pollution problems will require in-
novative economic, social-science, and natural-science research. The challenges
are particularly difficult because the hydrologic, ecologic, economic, and social
processes affecting the magnitude and scope of nutrient pollution and its conse-
quences are complex, multi-scaled, and spatially variable. To deal effectively with
this complex problem, a framework for incorporating human and environmental
interactions, such as the Millennium Ecosystem Assessment framework (see
Chapter 1) would prove useful. Nutrient pollution should be approached from a
broad perspective that uses systems thinking (see Chapter 4) and there are exam-
ples in which EPA is already taking steps in this direction with the Chesapeake
Bay Program and the New YorkNew Jersey Harbor Estuary Program. The prob-
lem may not be getting progressively worse, but there are still many challenges to
attaining further improvements. The prospects are that eutrophication will con-
tinue to be a challenge until policies to control nutrients are made more effective
(Cary and Migliaccio 2009; Spiertz 2009).
FIGURE 2-1 Sources of phosphorus and nitrogen in the Gulf of Mexico and Chesapeake
Bay. Source: EPA 2010b.
OCR for page 45
Challenges of the 21st Century 45
FIGURE 2-2 Narragansett Bay nitrogen loading from 1850 to 2015 under several
different scenarios. Scenario 0 (S0), current conditions and no improvements in
wastewater treatment; scenario 1 (S1), current conditions and implementation of all
mandated reductions in nutrient from wastewater-treatment plants; scenario 2 (S2), all
wastewater treatment plants have a maximum effluent nitrogen of 8 mg/L in summer,
25% reduction in nitrogen air-pollution concentrations, and 25% reduction in fertilizer
use in the watershed; scenario 3 (S3), all wastewater-treatment plants have a maximum
effluent nitrogen concentration of 3mg/L in summer, 50% reduction in nitrogen air-
pollution concetrations, and 50% reduction in fertilizer use in the watershed. Source:
Vadeboncouer et al. 2010. Reprinted with permission; copyright 2010, Estuaries and
Coasts.
Shifting Spatial and Temporal Scales
In the early days of environmental remediation and pollution control, the
problems were more obvious. One could see, indeed often even smell or taste,
the pollutants, and local causes could be easily identified. As progress has been
made in cleaning up the local problems and as more has been learned about the
health and environmental consequences of chronic low-dose exposures to di-
verse chemicals, much of the focus has moved to wider geographic areas. The
spatial scales required to understand emerging environmental issues vary widely
and are increasing as more is learned about the systems underlying the observed
phenomena.
Acid rain and photochemical air pollution are regional problems, and
monitoring, modeling, and control activities have shifted accordingly. EPA's
long-standing involvement in regional-scale air quality monitoring and modeling
research includes the multi-agency National Acid Precipitation Assessment Pro-
gram (NAPAP 1991), which was authorized by Congress in 1980 and informed
OCR for page 46
46 Science For Environmental Protection: The Road Ahead
the acid rain provisions of the 1990 Clean Air Act amendments. EPA continues
to work with other federal and state agencies to improve understanding of the
nature and consequences of air pollutant deposition to terrestrial and aquatic
ecosystems on regional scales. More recently, EPA has conducted and supported
research linking global climate projections to regional-scale air quality (EPA
2009), which has demonstrated the potential for global climate change to exac-
erbate the challenge of meeting health-based air quality standards. Regional
long-term approaches for assessment and problem-solving have also been im-
plemented in the water quality arena, including for the Chesapeake Bay, the
Florida Everglades, and the Great Lakes Basin (Table 2-2). In the future, EPA
will need to develop a better understanding of the sources, transport, and fate of
global-scale pollutants to avoid the possibility that little improvement in envi-
ronmental quality occurs even when local investment is large. For example, al-
though lead from local sources, such as coal-fired power plants, is important,
these local emissions are superimposed on a global background of lead, some of
which is transported on intercontinental scales from both natural and anthropo-
genic sources (UNEP 2006). Mercury transport at the regional and global scale
is another example. It is not feasible for EPA to undertake all the global-scale
monitoring and modeling that are needed, but it can work proactively with other
US federal agencies (such as the National Oceanic and Atmospheric Administra-
tion, the National Aeronautics and Space Administration, and the National Sci-
ence Foundation) and with international organizations to ensure that the issues
that it most needs to understand remain high on research agendas. (See Chapter
4 for a discussion on collaboration.) Current environmental challenges are ex-
panding not only in space but also in time. Some responses to perturbations are
rapid (such as algal blooms), others are slow (such as vegetation response to
climate change). To understand how and why these effects unfold, long-term
data are needed to characterize the changes, the causes, and the potential impli-
cations of different policy options. (The needs for such data are discussed fur-
ther in Chapters 3 and 4.) Without the perspective provided by long-term data, it
is easy to assume wrongly that short-term variations in environmental character-
istics reflect substantive changes in the environment, and it is easy to miss im-
portant but subtle or slow changes in the environment.
SUMMARY
This chapter discusses some of the major factors driving changes in the
environment and gives illustrative examples of the complex and multi-
disciplinary challenges that EPA faces now and will probably face in the future.
To address those challenges, EPA will need to continue to develop and support
scientific methods, tools, and technologies that apply a systems-thinking ap-
proach to understand environmental changes and their effects on human health
(see Chapter 4).
OCR for page 47
TABLE 2-2 Large Regional Water Programs in the US Environmental Protection Agency
Watershed or Water System Key Stressors and Issues EPA Leadership Science and Engineering Focus
Chesapeake Bay, North America's · Eutrophication caused by nutrient · EPA, Region 3 Mid-Atlantic · Developed a number of innovative
largest estuary (EPA 2012e) enrichment · Chesapeake Bay: A Framework tools
· Nitrogen for Action (EPA 1983a,b) provided a · Nitrogen-removal technology at
· Stressed by pressures of growing framework for additional research wastewater-treatment plants
populations, industrial pollution, and policy initiatives based on the · Computer model built to simulate
atmospheric deposition of air pollutants, Chesapeake Bay Program, which was how the massive 64,000-mi2 watershed
and conversion of forests to farms and established in 1983 as a partnership of processes nutrient and sediment
urban areas the EPA, Maryland, and Virginia allocations
Everglades, a sub-tropical wetlands · Altered hydrology · EPA, Region 4 · Aquifer storage and recovery
watershed Florida, which houses the · Mercury · The Comprehensive Everglades · Ecosystem restoration
Everglades National Park (EPA 2007) · Phosphorus Restoration Plan is an ambitious, · One of the strongest aspects of
· Soil erosion multi-billion-dollar and multi-decadal the Comprehensive Everglades
· One of the most threatened restoration program involving federal Restoration Plan science program is
subtropical preserves in the United and state governments its monitoring and assessment program
States · EPA developed the Everglades (see, for example, NRC 2003)
Ecosystem Assessment Program, which · Developed scientific tests,
contributes to the joint federalstate experiments, and physical models
Comprehensive Everglades Restoration
Plan
Great Lakes Basin, the largest · Climate change associated with · EPA, Region 5 · The largest investment in the
transboundary freshwater system in the lowering lake level · Great Lakes Restoration Initiative Great Lakes in two decades
world (Lakes Erie, Huron, Michigan, · Invasive species action plan · Priority "focus areas" were
Ontario, and Superior and five major · Nutrients · A Great Lakes inter-agency task "1) cleaning up toxics and toxic hot spot
connecting rivers: Detroit, Niagara, · Pathogens force was formed to coordinate federal areas of concern; 2) combating invasive
St. Clair, St. Lawrence, and St. Mary's) · Mercury loading (alone and with and bi-national restoration efforts species; 3) promoting near-shore health
(EPA 2011e). contaminated sediments) by protecting watersheds from polluted
· Effects on community health, run-off; 4) restoring wetlands and other
tourism, fisheries, power industry, and habitats; and 5) tracking progress,
grids; human health and ecosystems are education, and working with strategic
seen as being at risk partners" (MI DNR 2011)
47
OCR for page 48
48 Science For Environmental Protection: The Road Ahead
The drivers outlined in this chapter are often overlapping and their nature
is changing over time. For example, in the United States, chemical exposures
from industrial facilities are decreasing significantly; dispersed, non-point, and
less controllable exposures from chemicals used in products may represent a
larger percentage of the current chemical burden to ecosystems and humans. As
illustrated by the degradation of the Chesapeake Bay, multiple overlapping fac-
tors, such as land use and changing land-use patterns, population growth, the
agricultural use of fertilizers and pesticides, and direct and non-point chemical
exposures may result in human and environmental effects. The complexity of
these interacting factors in environmental degradation creates great challenges
for environmental science and decision-making.
The siloed, disciplinary approaches that have often been taken to monitor
for and characterize singular types of effects and to develop control measures
will not be sufficient to understand and prevent environmental changes and their
health effects. There is a need for greater attention to understand the complex
systems in which human activities are causing effects and how those effects
interact. Ultimately, prevention of these complex effects will require greater
systematic efforts to understand the way in which products, consumptive sys-
tems (such as energy), communities, and other human activities are designed
and carried out.
REFERENCES
Allen, J.G., M.D. McClean, H.M. Stapleton, J.W. Nelson, and T.F. Webster. 2007. Per-
sonal exposure to polybrominated diphenyl ethers (PBDEs) in residential indoor
air. Environ. Sci. Technol. 41(13):4574-4579.
Alvarez, R.A., S.W. Pacala, J.J. Winebrake, W.K. Chameides, and S.P. Hamburg. 2012.
Greater focus needed on methane leakage from natural gas infrastructure. Proc.
Natl. Acad. Sci. USA 109(17):6435-6440.
ASCE (American Society of Civil Engineers). 2009. Report Card 2009 Grades [online].
Available: https://apps.asce.org/reportcard/2009/grades.cfm [accessed April 29, 2012].
Bates, B.C., Z.W. Kundzewicz, S.Wu, and J.P. Palutikof, eds. 2008. Climate Change and
Water. IPCC Technical Paper VI. Geneva: Intergovernmental Panel on Climate
Change [online]. Available: http://www.ipcc.ch/pdf/technical-papers/climate-change-
water-en.pdf [accessed Mar. 28, 2012].
Bloomer, B.J., J.W. Stehr, C.A. Piety, R.J. Salawitch, and R.R. Dickerson. 2009.
Observed relationship of ozone air pollution with temperature and emissions.
Geophys. Res. Lett. 36:L09803.
Brownstone, D. and T.F. Golob. 2009. The impact of residential density on vehicle usage
and energy consumption. Journal of Urban Economics. 65:91-98.
Bullard, R.D. 2000. Dumping in Dixie: Race, Class, and Environmental Quality, 3rd Ed.
Boulder, CO: Westview Press.
Bushaw-Newton, K.L., and K.G. Sellner. 1999. Harmful Algal Blooms. In NOAA's State
of the Coast Report. Silver Spring, MD: National Oceanic and Atmospheric Admin-
istration [online]. Available: http://oceanservice.noaa.gov/websites/retiredsites/sotc_
pdf/hab.pdf [accessed Mar. 27, 2012].
OCR for page 49
Challenges of the 21st Century 49
Cary, R.O., and K.W. Migliaccio. 2009. Contribution of wastewater treatment plant ef-
fluents to nutrient dynamics in aquatic systems: A review. Environ. Manage. 44(2):
205-217.
CDC (Centers for Disease Control and Prevention). 2009. Fourth National Report on
Human Exposure to Environmental Chemicals. Department of Health and Human
Services, Centers for Disease Control and Prevention [online]. Available: http://
www.cdc.gov/exposurereport/pdf/FourthReport.pdf [accessed Mar. 27, 2012].
Confalonieri, U., B. Menne, R. Akhatar, K.L. Ebi, M. Haugengue, R.S. Kovats, B.
Revich, and A. Woodward. 2007. Human health. Pp. 391-431 in Climate Change
20007: Impacts, Adaptation and Vlunterability. Contribution of Working Group II
to the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden, and C.E.
Hanson, eds. Cambridge: Cambridge University Press [online]. Available: http://
www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-chapter8.pdf [accessed Apr.
9, 2012].
Diaz, R.J., and R. Rosenberg. 2008. Spreading dead zones and consequences for marine
ecosystems. Science 321(5891):926-929.
EPA (US Environmental Protection Agency). 1983a. Chesapeake Bay: A Framework for
Action. US Environmental Protection Agency, Region 3, Philadelphia, PA
[online]. Available: http://www.chesapeakebay.net/content/publications/cbp_12405.
pdf [accessed Mar. 29, 2012].
EPA (US Environmental Protection Agency). 1983b. Chesapeake Bay: A Framework for
Action-Appendices. US Environmental Protection Agency, Region 3, Philadelphia,
PA [online]. Available: http://www.chesapeakebay.net/content/publications/cbp_132
62.pdf [accessed Mar. 29, 2012].
EPA (US Environmental Protection Agency). 2005. Program Needs for Indoor Environ-
ments Research (PNIER). EPA 402-B-05-001. US Environmental Protection Agency,
March 2005 [online]. Available: http://www.epa.gov/iaq/pdfs/pnier.pdf [accessed
July 20, 2012].
EPA (US Environmental Protection Agency). 2006. Wadeable Streams Assessment: A
Collaborative Survey of the Nation's Streams. EPA 841-B-06-002. Office of
Water, US Environmental Protection Agency, Washington, DC [online]. Avail-
able: http://www.cpcb.ku.edu/datalibrary/assets/library/projectreports/WSAEPArepo
rt.pdf [accessed Mar. 28, 2012].
EPA (US Environmental Protection Agency). 2007. Everglades Ecosystem Assessment:
Water Management and Quality, Eutrophication, Mercury Contamination, Soils
and Habitat-Monitoring for Adaptive Management. EPA 904-R-07-001. US Envi-
ronmental Protection Agency, Region 4, Athens, GA [online]. Available: http://
www.epa.gov/region4/sesd/reports/epa904r07001.html [accessed Mar. 29, 2012].
EPA (US Environmental Protection Agency). 2009. Assessment of the Impacts of Global
Change on Regional US Air Quality: A Synthesis of Climate Change Impacts on
Ground-Level Ozone, An Interim Report of the US EPA Global Change Research
Program. EPA/600/R-07/094F. National Center for Environmental Assessment,
Office of Research and Development, US Environmental Protection Agency,
Washington, DC [online]. Available: http://www.mwcog.org/uploads/committee-
documents/bV5cWVxb20090417102640.pdf [assessed July 31, 2012].
EPA (US Environmental Protection Agency). 2010a. FY 2011-2015 EPA Strategic Plan:
Achiving Our Vision. US Environmental Protection Agency, September 30, 2010
[online]. Available: http://www.epa.gov/planandbudget/strategicplan.html [accessed
Jan. 17, 2012].
OCR for page 50
50 Science For Environmental Protection: The Road Ahead
EPA (US Environmental Protection Agency). 2010b. Discussion Document: Coming
Together for Clean Water, Background Information on Proposed Discussion
Topics. US Environmental Protection Agency Forum, April 15, 2010 [online].
Available: http://blog.epa.gov/waterforum/discussion-document/ [accessed Mar. 29,
2012].
EPA (US Environmental Protection Agency). 2011a. Inventory of US Greenhouse Gas
Emissions and Sinks: 1990-2009. EPA 430-R-11-005. US Environmental Protection
Agency, Washington, DC. April 15, 2011[online]. Available: http://www.epa.gov/
climatechange/emissions/downloads11/US-GHG-Inventory-2011-Complete_Report.
pdf [accessed Mar. 28, 2012].
EPA (US Environmental Protection Agency). 2011b. Human Disease and Condition.
Report on the Environment [online]. Available: http://cfpub.epa.gov/eroe/index.
cfm?fuseaction=list.listBySubTopic&ch=49&s=381 [accessed Mar. 6, 2012].
EPA (US Environmental Protection Agency). 2011c. Exposure Model for Individuals
(EMI). Human Exposure and Atmospheric Science Program, US Environmental
Protection Agency [online ]. Available: http://www.epa.gov/heasd/products/emi/
emi.html [accessed July 20, 2012].
EPA (US Environmental Protection Agency). 2011d. The Benefits and Costs of the Clean
Air Act from 1990 to 2020. Office of Air and Radiation, US Environmental Pro-
tection Agency, March 2011 [online]. Available: http://www.epa.gov/oar/sect812/
feb11/fullreport.pdf [accessed July 22, 2012].
EPA (US Environmental Protection Agency). 2011e. Great Lakes. US Environmental
Protection Agency [online]. Available: http://epa.gov/greatlakes/ [accessed Mar.
29, 2012].
EPA (US Environmental Protection Agency). 2012a. An Introduction to Indoor Air
Quality (IAQ). [online]. Available: http://www.epa.gov/iaq/ia-intro.html#content
[accessed July 20, 2012].
EPA (US Environmental Protection Agency). 2012b. Gas and Vapor Intrusion. Ground
Water and Ecosystems Restoration Reseach, US Environmental Protection Agency
[online]. Available: http://www.epa.gov/ada/gw/vapor.html [accessed July 20, 2012].
EPA (US Environmental Protection Agency). 2012c. Soil Gas Sample Collection and
Sample Analysis Methods. Underground Storage Tanks, Office of Solid Waste and
Emergency Response, US Environmental Protection Agency [online]. Available:
http://www.epa.gov/oust/cat/pvi/soil_gas.htm [accessed July 20, 2012].
EPA (US Environmental Protection Agency). 2012d. Nutrient Pollution [online].
Available: http://epa.gov/nutrientpollution/index.html [accessed Mar. 28, 2012].
EPA (US Environmental Protection Agency). 2012e. Chesapeake Bay Program Office.
US Environmental Protection Agency Region 3: The Mid-Atlantic States [online].
Available: http://www.epa.gov/region3/chesapeake/ [accessed Mar. 29, 2012].
Erdmann, L., and T.E. Graedel. 2011. Criticality of non-fuel minerals: A review of major
approaches and analyses. Environ. Sci. Technol. 45(18):7620-7630.
Frumkin, H. 2002. Urban sprawl and public health. Public Health Rep. 117(3):201-217.
Grun, F., and B. Blumberg. 2006. Environmental obesogens: Organotins and endocrine
disruption via nuclear receptor signalling. Endocrinology 147(6 suppl.): S50-S55.
Holloway, A.C., D.Q. Cuu, K.M. Morrison, H.C. Gerstein, and M.A. Tarnopolsky. 2007.
Transgenerational effects of fetal and neonatal exposure to nicotine. Endocrine
31(3):254-259.
OCR for page 51
Challenges of the 21st Century 51
Hoskins, J.A. 2011. Health effects due to indoor air pollution. Pp. 665-676 in Survival and
Sustainability: Environmental Concerns in the 21st Century, H. Gökçekus, U.
Türker, and J.W. LaMoreaux, eds. Environmental Earth Sciences 5. Berlin: Springer.
Howarth, R.W. 2008. Coastal nitrogen pollution: A review of sources and trends globally
and regionally. Harmful Algae 8(1):14-20.
IOM (Institute of Medicine). 2009. Global Issues in Water, Sanitation, and Health:
Workshop Summary. Washington, DC: National Academies Press.
IPCC (Intergovernmental Panel on Climate Change). 2007. Summary for policy makers.
Pp. 1-19 in Climate Change 2007: The Physical Science Basis, S. Solomon, M.
Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller, eds.
Cambridge, UK: Cambridge University Press.
IPCC(Intergovernmental Panel on Climate Change). 2012. The summary for
policymakers. Pp. 1-19 in Managing the Risks of Extreme Events and Disasters to
Advance Climate Change Adaptation, C.B. Field, V. Barros, T.F. Stocker, D. Qin,
D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.K. Plattner, S.K. Allen,
M. Tignor, and P.M. Midgley, eds. A Special Report of Working Groups I and II
of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge
University Press [online]. Available: http://ipcc-wg2.gov/SREX/images/uploads/
SREX-SPM_FINAL.pdf [accessed Mar. 28, 2012].
IWGSCC( Interagency Working Group on Social Cost of Carbon). 2010. Social Cost of
Carbon for Regulatory Impact Analysis Under Executive Order 12866. Technical
Support Document. Interagency Working Group on Social Cost of Carbon, US
Government [online]. Available: http://www.epa.gov/oms/climate/regulations/scc-
tsd.pdf [accessed July 21, 2012].
Jacob, D.J., and D.A. Winner. 2009. Effect of climate change on air quality. Atmospheric
Environment. 43:51-63.
Jaramillo, P., W.M. Griffin, and S. Matthews. 2007. Comparative life-cycle air emissions
of coal, domestic natural gas, LNG, and SNG for electricity generation. Environ.
Sci. Technol. 41(17):6290-6296.
Kirchner, S., T. Kieu, C. Chow, S. Casey, and B. Blumberg. 2010. Prenatal exposure to
the environmental obesogen tributyltin predisposes multipotent stem cells to be-
come adipocydes. Mol. Endocrinol. 24(3):526-539.
Langpap, C. I. Hascic, and J. Wu. 2008. Protecting watershed ecosystems through tar-
geted local land use policies. Am. J. Agr. Econ. 90(3):684-700.
Mac Kenzie, W.R., N.J. Hoxie, M.E. Proctor, M.S. Gradus, K.A. Blair, D.E. Peterson,
J.J. Kazmierczak, D.G. Addiss, K.R. Fox, J.B. Rose, and J.P. Davis. 1994. A
massive outbreak in Milwaukee of Cryptosporidium infection transmitted through
the public water supply. N. Engl. J. Med. 331(3):161-167.
MI DNR (Michigan Department of Natural Resources). 2011. Michigan Benefits from
Great Lakes Restoration Initiative Grants: Over $1.5 Million in Grants Awarded to
Local Communities and Organizations [online]. Available: http://www.michigan.
gov/dnr/0,4570,7-153--265166--RSS,00.html [accessed Mar. 29, 2012].
Milly, P.C.D., J Betancourt, M. Falkenmark , R.M. Hirsch, Z.W. Kundzewicz, D.P. Let-
tenmaier, and R.J. Stouffer. 2008. Stationarity is dead: Whither water management.
Science 319(5863):573-574.
NAPAP (US National Acid Precipitation Assessment Program). 1991. 1990 Integrated
Assessment Report. Washington DC: NAPAP Office of the Director. November
1991.
OCR for page 52
52 Science For Environmental Protection: The Road Ahead
NOAA (National Oceanic and Atmospheric Administration). 2012a. Keeping Seafood Safe.
National Oceanic and Atmospheric Administration [online]. Available: http://www.
noaa.gov/100days/Keeping_Seafood_Safe.html [accessed Feb. 27, 2012].
NOAA (National Oceanic and Atmospheric Administration). 2012b. State of the Coast.
National Oceanic and Atmospheric Administration [online]. Available: http://state
ofthecoast.noaa.gov/ [accessed Mar. 28, 2012].
Nowak, D.J., and E.J. Greenfield. 2012. Tree and impervious cover in the United States.
LandscapeUrban Plan. 107(1):21-30.
NRC (National Research Council). 2003. Adaptive Monitoring and Assessment for the
Comprehensive Everglades Restoration Plan. Washington, DC: National Academies
Press.
NRC (National Research Council). 2006. Human Biomonitoring for Environmental
Chemicals. Washington, DC: National Academies Press.
NRC (National Research Council). 2008. Water Implications of Increased Biofuel
Production in the US Washington DC: National Academies Press.
NRC (National Research Council). 2010. Hidden Costs of Energy: Unpriced Consequences
of Energy Production and Use. Washington, DC: National Academies Press.
NRC (National Research Council). 2011. Renewable Fuel Standard: Potential Economic
and Environmental Effects of US Biofuel Policy. Washington DC: National
Academies Press.
Pejchar, L., and H.A. Mooney. 2009. Invasive species, ecosystem services and human
well-being. Trends Ecol. Evol. 24(9):497-504.
Pimentel, D., R. Zuniga, and D. Morrison. 2005. Update on the environmental and
economic costs associated with alein-invasive species in the United States.
Ecological Economics. 52(3):273-288.
Pryor, D., E. Saarman, D. Murray, and W. Prell. 2007. Nitrogen Loading from Wastewater
Treatment Plants to Upper Narragansett Bay. Narragansett Bay Collection Paper 2.
University of Rhode Island [online]. Available: http://digitalcommons.uri.edu/cgi/
viewcontent.cgi?article=1002&context=nbcollection [accessed Mar. 28, 2012].
Savage. N.. and M.S. Diallo. 2005. Nanomaterials and water purification: Opportunities
and challenges. J. Nanopart. Res. 7(4-5):331-342.
Schmitz, O.J., and T.E. Graedel. 2010. The Consumption Conundrum: Driving the
Destruction Abroad. Environment 360, April 26, 2010 [online]. Available: http://
e360.yale.edu/feature/the_consumption_conundrum_driving_the_destruction_abro
ad/2266 [accessed Mar. 28, 2012].
Selman, M.S., S. Greenhalgh, R. Diaz, and Z. Sugg. 2008. Eutrophication and Hypoxia in
Coastal Areas: A Global Assessment of the State of Knowledge. WRI Policy Note
No. 1. World Resources Institute [online]. Available: http://pdf.wri.org/eutrophi
cation_and_hypoxia_in_coastal_areas.pdf [accessed Mar. 28, 2012].
Shortle, J.S., M. Ribaudo, R.D. Horan, and D. Blanford. 2011. Reforming agricultural
nonpoint pollution policy in an increasingly budget-constrained environment.
Environ. Sci. Technol. 46(3):1316-1325.
Spiertz, J.H.J. 2009. Nitrogen, sustainable agriculture and food security: A review. Pp.
635-651 in Sustainable Agriculture, E. Lichtfouse, M. Navarrete, P. Debaeke, V.
Souchere, and C. Alberola, eds. Dordrecht: Springer.
Squires, G.D. 2002. Urban Sprawl: Causes, Consequences and Policy Responses.
Washington, DC: The Urban Institute.
Stoner, N.K. 2011. Testimony of Nancy K. Stoner, Acting Assistant Administrator for
Water, US Environmental Protection Agency Before the Subcommittee on Water
Resources and Environment Committee on Transportation and Infrastructure US
OCR for page 53
Challenges of the 21st Century 53
House of Representatives, June 24, 2011 [online]. Available: http://republicans.
transportation.house.gov/Media/file/TestimonyWater/2011-12-14-Stoner.pdf
[accessed Mar. 28, 2012].
UN (United Nations). 1999. The World at Six Billion. ESA/P/WP.154. Population
Division, Department of Economic and Social Affairs, UN Secretariat [online].
Available: http://www.un.org/esa/population/publications/sixbillion/sixbillion.htm
[accessed July 31, 2012].
UN (United Nations). 2011. World Population to Reach 7 Billion on 31 October. United
Nations Population Fund Press Release: May 3, 2011 [online]. Available: http://
www.unfpa.org/public/home/news/pid/7597 [accessed Mar. 27, 2012].
UNEP (United Nations Environmental Programme). 2006. Report of the First Meeting of
the Lead and Cadmium Working Group, September 18-22, 2006, Geneva,
Switzerland. United Nations Environmental Programme [online]. Available: http://
www.unep.org/hazardoussubstances/Portals/9/Lead_Cadmium/docs/Interim_reviews
/K0653416%20-%20Lead%20Cadmium%20Report.pdf [accessed Mar. 28, 2012].
US Census Bureau. 2012. World POPClock Projection [online]. Available: http://www.
census.gov/population/popclockworld.html [accessed Mar. 28, 2012].
USDA (US Department of Agriculture). 2006. The human influenced forest. Pp. 19-28 in
The State of Chesapeake Forests, E. Sprague, D. Burke, S. Claggett, and A. Todd,
eds. Arlington, VA: Conservation Fund [online]. Available: http://www.na.fs.fed.
us/watershed/pdf/socf/Full%20Report.pdf [accessed July 6, 2012].
USDA (US Department of Agriculture). 2012. Gateway to Invasive Species Information
Covering Federal, State, Local, and International Sources. US Department of
Agriculture, National Invasive Species Information Center (NISIC) [online].
Available: http://www.invasivespeciesinfo.gov [accessed Mar. 28, 2012].
Vadeboncouer, M.A., S.P. Hamburg, and D. Pryor. 2010. Modeled nitrogen loading to
Narragansett Bay: 1850 to 2015. Estuar. Coast. 33(5):1113-1137.
Wallace, L., and W. Ott. 2011. Personal exposure to ultrafine particles. J. Expo. Sci. En-
viron. Epidemiol. 21(1):20-30.
Wang, Y., and M.A. Beydoun. 2007. The obesity epidemic in the United States--gender,
age, socioeconomic, racial/ethnic, and geographic characteristics: A systematic
review and meta-regression analysis. Epidemiol. Rev. 29(1):6-28.
Wiesner M.R., and J-Y. Bottero. 2007. Environmental Nanotechnology: Applications and
Impacts of Nanomaterials. New York: McGraw Hill. 540 pp.
Worldwatch Institute. 2011. The State of Consumption Today. Worldwatch Institute
[online]. Available: http://www.worldwatch.org/node/810#1 [accessed Feb. 27, 2012].
Wulder, M.A., J.G. Masek, W.B. Cohen, T.R. Loveland, and C.E. Woodcock. 2012.
Opening the archive: How free data has enabled the science and monitoring
promise of Landsat. Remote Sens. Environ. 122:2-10.
Younger, M., H.R. Morrow-Almeida, S.M. Vindigni, and A.L. Dannenberg. 2008. The
built environment, climate change, and health opportunities for co-benefits. Am. J.
Prev. Med. 35(5):517-526.
