Efforts of the US Environmental Protection Agency (EPA) to address environmental degradation over the last 40 years have had some marked successes, including reductions in particulate and sulfur air pollution, reductions in industrial 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 chemicals, and water-quality declines—requires understanding the nature of the problems and their relationships to other phenomena. In particular, solving environmental 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 phenomena 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 accomplishments 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 consequences. Those disasters can arise from natural events such as storms, earthquakes, 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).
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 environmental problems EPA will face in the next 10 years or more, but it can identify some of the common drivers and common characteristics of problems. The specific topics discussed in this chapter were identified based on committee expertise 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 socioeconomic factors are directly and indirectly driving environmental 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 environment. 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.
It took until 1800 AD for mankind to reach a population of 1 billion people, but only required 123 more years to reach 2 billion, 33 more years to reach 3 billion, and about 13–14 more years for each additional billion people thereafter (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 moderation, 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);
increasing numbers of manufactured chemicals and products introduced into the environment (EPA 2011a); and increased food and water demand and concomitant 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 influence 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 development, and changes in forestry practices.
Population growth and demographic transitions have increased the requirement 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 (including 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 agriculture 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.
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 economic 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 efforts to monitor and understand land-use changes.
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 extraction or production, fuel combustion, and waste discharge or disposal. The April 2010 blowout of British Petroleum’s Macondo deepwater oil well illustrated 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 natural gas is recognized as a fuel that inherently emits less greenhouse gas (about half) than coal when combusted (Jaramillo et al. 2007). The comparative advantages 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, transportation, 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 production of corn as an ethanol feedstock has resulted in increased nutrient runoff and corresponding eutrophication of coastal waters, including the Gulf of Mexico (NRC 2008, 2011). Given current water-use efficiencies, large quantities of water are also required for irrigation and the intensification of agricultural practices can increase erosion (NRC 2008, 2011). Further research is required to develop new perennial feedstocks that would require less tillage and have high
nutrient-use efficiencies so that soils and nutrients would be held in place. Ultimately, 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 influencing one fuel type can have ripple effects across the life cycle of multiple fuels. For example, emissions requirements on power plants could reduce air pollutant 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 environmental 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 elements from the rare earth and platinum series metals; today it requires 60 elements, 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 recover the (sometimes toxic) materials used in electronic devices. EPA is challenged 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 happened 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). Understanding how new technologies will influence the application and use of existing
technologies will be important in ensuring the net benefit of EPA’s efforts. Social-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 movement 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 recreation (such as pets or game animals). Most do not become established in the locations 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 (Pimentel et al. 2005; Pejchar and Mooney 2009). Increasingly, people are introduced to new exposure pathways and vectors through other animals that are potential carriers of diseases to which humans and other animals lack immunity.
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, concentrations, 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
(Confalonieri et al. 2007). Factors contributing to deteriorating air quality include 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 bypass of raw sewage (NOAA 2012b). Factors contributing to water quality and coastal-system degradation include land use, urban sprawl, climate change, and energy systems.
• Non-point-source pollution and nutrient effects associated with agricultural runoff of nutrients and soils. Factors contributing to non-point-source pollution and nutrient effects include climate change, land use, and technologic change (NRC 2011).
• Expanding quantities of waste with a wider array of component materials (Schmitz and Graedel 2010). Factors contributing to expanding quantities of waste include population growth, energy usage, technologic change, and changing 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 accessing, 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 exposures to numerous stressors rather than high-level exposures to individual stressors, 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-
posures and reducing or preventing associated health effects can be more challenging.
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. Identifying 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, cardiovascular 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 medical care decrease human resilience and the ability to adapt; disadvantaged communities are at increased risk when faced with increased exposure. Genetic factors also influence susceptibility and underscore the importance of gene— environment interaction in determining health outcomes.
Transgenerational effects and sensitive populations are also of great concern for public health. Exposure to chemicals and other stressors during gestation 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 metabolism 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 exposures 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.
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 systems, 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 effects. 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 understanding 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 population 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 polybrominated diphenyl ethers were found in the serum of almost the entire population, as were several polyfluorinated compounds used to impart nonstick characteristics 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 coming years and allow the exploration of the progression of disease from an absorbed dose to a targeted health outcome, including the influence of genetic information on susceptibility and biomarkers.
Novel understanding of population exposure brings new challenges for environmental 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
ecologic implications, identify sources of exposure, and trace the pathways of human exposure. In addition to the traditional single-substance approach, the recognition 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 2011–2015 strategic plan is “taking action on climate change and improving air quality” (EPA 2010a). This goal encompasses mandates under the Clean Air Act and other statutes, obligations under international treaties and agreements, and executive branch commitments. The following 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 pollutants released into or produced in the ambient atmosphere. That is accomplished 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 ). 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 effects, 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 programs 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). Exposures to certain pollutants released from building materials and consumer products 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 corresponding health effects (EPA 2005, 2011c, 2012a,b,c).
The agency’s efforts to improve air quality continue to have high priority despite decades of progress because the economic costs that air pollution imposes 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 damages. 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 0.6°C 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 temperature, 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 influenced. Many of the factors discussed earlier in this chapter will have direct and indirect influences on climate change, which will itself influence land use patterns and other drivers.
There is evidence that the climate change that has occurred in recent decades 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.
tat, and food production (IPCC 2007, 2012). The scientific and technical challenges associated with the goal of taking action on climate change and improving air quality are broad and complex. Finding efficient and effective approaches to mitigate and adapt to climate change and improve air quality requires systems thinking and research in diverse disciplines, including environmental engineering, atmospheric sciences, biology, ecology, engineering, economics, sociology, and public health. EPA has been involved in climate-change research and policy development for more than 2 decades see (Box 2-1). Beyond its statutory assignments, EPA undertakes broader efforts to address climate change and improve air quality through various approaches that include public education, consumer information, technical exchanges, grants, and voluntary certification programs.
Regulatory Drivers for Air Quality and Climate Change
EPA’s regulatory drivers in the climate-change and air-quality arena have helped to marshal resources in and outside the agency, which has yielded substantial advances in scientific understanding and technology. For example, designation of particulate matter and photochemical oxidants as criteria pollutants under the Clean Air Act has led to thousands of epidemiology and toxicology studies that have improved the understanding of associated health effects and provided the scientific basis of standard-setting and regulatory efforts. In contrast, one challenge posed by regulatory drivers is the blind spots that they create for issues deemed outside the scope of regulatory authority or issues that have lower priority because of later deadlines or milder penalties for noncompliance. For example, EPA recognizes both indoor pollution and outdoor air pollution as posing important health risks, but the agency places relatively low priority on indoor air-quality research due to lack of a regulatory mandate. The structure of the Clean Air Act has also encouraged heavier emphasis on criteria pollutants over other hazardous air pollutants, human health over ecosystem effects, and industrial sources over agricultural sources of pollutants. EPA faces a challenge in trying to balance its own research portfolio between issues that arise out of its regulatory mandate and issues that warrant attention from the perspective of human health and welfare but for which there is no legislative mandate. Approaches for how EPA can support and promote science and engineering in the face of these challenges are discussed in Chapters 4 and 5.
Continued research efforts and leadership are important for a strong understanding of the health effects and fate and transport of conventional air pollutants, including both hazardous air pollutants and criteria pollutants, and understanding the synergistic effects of air-pollutant mixtures. EPA would benefit from advancing the understanding of sources, transformations, and transport of pollutants, including improved quantification and forecasting of international contributions to US air-quality challenges (for example, mercury deposition and
ozone nonattainment). As it grapples with climate change, this type of research would give the agency better understanding of interactions between climate change and air quality with respect to both atmospheric responses and opportunities for mitigation.
The Global Change Research Act of 1990 established a framework for federal research that continues today as the US Global Change Research Program. EPA is one of 13 agencies and departments participating in the program and has special responsibility for research to assess consequences of global change for air and water quality, aquatic ecosystems, and human health. EPA is responsible for the greenhouse-gas inventory that the United States submits to the secretariat of the United Nations Framework Convention on Climate Change, which the United States ratified in 1992. In 2007, the US Supreme Court held that EPA is responsible for regulating greenhouse gas emissions as air pollutants under the Clean Air Act if the administrator finds that the act’s endangerment condition is satisfied. EPA Administrator Lisa Jackson made that finding in December 2009. Accordingly, the agency has set greenhouse-gas emission standards for motor vehicles and is moving forward with greenhouse-gas emission regulations for stationary sources. The Consolidated Appropriations Act of 2008 required EPA to promulgate requirements for large sources of greenhouse-gas emissions to track and report these emissions.
During the 1970s, key legislation that focused on developing sound policies for protection of surface water and groundwater was passed, including the Clean Water Act and the Safe Drinking Water Act. Both concentrated on water quality and public health, but the presence of different goals, approaches, and targets led to fragmented water science and research agendas (Table 2-1). It has long been argued that a harmonization of the two acts is needed, and some view a national water quality policy as a threat to or a necessity for achieving secure and safe water supplies and addressing key challenges in the future.
Drivers of Water-Quality Policy
The major drivers for developing national research and science agendas are focused on looming water problems. Since 1970, although understanding of hydrologic systems has advanced, water problems have been overshadowed by the challenges and rapid changes in land use and economic systems (Langpap et
al. 2008). Provision of a safe and sustainable supply of water for humanity is widely expected to be one of the central issues of global politics and economics during this century. Water is also closely tied to many other leading sustainability issues such as energy, climate, and food security. Given increasing demands on freshwater supplies, particularly in the more arid regions of the western United States, the challenges of providing clean water are prominent today and will likely continue to be a concern in the future. Demands include domestic uses (potable and landscaping), agricultural uses, and support of ecosystems and biodiversity, and global change will exacerbate the tension among those demands.
The climate—water nexus presents new challenges and will require substantial investment in scientific research for managing this stressed resource in regions where water is scarce and in regions where water is plentiful. Regions experiencing water stress are projected to double by 2050 as a result of climate change (Bates et al. 2008). There is evidence that global climate change will increase the threat to human health, ecosystems, and socioeconomic conditions (IPCC 2007). As previously discussed, there will probably be direct effects on human health due to weather and climate extremes (for example, extremes in temperature and precipitation) and disasters caused by these extreme weather events (such as heat waves, floods, and hurricanes) (IOM 2009). Water is at the heart of understanding climate-change threats, and a new strategy for interdisciplinary research programs is imperative if the threat is to be handled without large adverse effects.
|ISSUE||Clean Water Act of 1972||Safe Drinking Water Act of 1976|
|Goals||• Swinnnable, fishable water
• Ecologic quality addressing ambient waters and discharges
• Standards developed at the state level
|• “Safe” drinking water as defined by maximum contaminant levels for final drinking-water or performance standards
• Nationally consistent standards
|Technology||• Little advancement in routine wastewater treatment or monitoring
• Technologic advances associated with state efforts in wastewater reclamation
|• New monitoring tools
• New treatment technology to address new contaminants
• Sensor technology associated with distribution systems and water security
|Science||• Impaired waters and development of hydrologic models
• Predictive modeling
• Source tracking methods using molecular tools
|• Advancement of risk-assessment frameworks and methods
• Groundwater models
• National databases
|Policies||• Beaches Environmental Assessment and Coastal Health Act
• Nutrient criteria
|• Contaminant Candidate List|
The ability to meet the global need for an adequate water supply will come from new scientific insights that span traditional disciplines and from innovative policy based on that science. Global water-research agendas have begun to address needs in the various elements of science, engineering, technology, and policy—drought and flood initiatives associated with climate variability, mitigation of water-related disasters, enhancement of water quality, emerging contaminants, interactions between water and food security, water and human settlements, groundwater sustainability, advanced water-treatment technologies, and ecohydrology. Related cross-cutting issues include the building of research and technology capacity, education, governance, and international relationships associated with water.
In addition to being driven by evolving water-quality problems, water-policy change is likely required to respond to tightened public budgets and increased concerns about efficiency in water-quality regulation (Stoner 2011). For example, water-pollution control in agriculture, a leading cause of non—point-source pollution problems in the United States, has been pursued largely through voluntary compliance strategies supplemented by public assistance through the adoption of pollution control practices. Reduced federal and state budgets may require significant policy innovations if water-quality goals are to be achieved with reduced financial support (Shortle et al. 2011).
Water Technology and Infrastructure Research
Monitoring technology is a vital component of water science. Emerging concerns about contaminants have appeared dramatically (for example, the outbreak of Cryptosporidium in Milwaukee, Wisconsin; Mac Kenzie et al. 1994) and resulted in the need for tools to be developed quickly or have arisen via advances in analytic capabilities (for example, identification of pharmaceuticals in the water supply). (See Chapter 3 for a discussion of these tools.) Although the health effects of some contaminants are clear, in most cases there are a host of reasons why the Clean Water Act and the Safe Drinking Water Act have resulted in a limited record of accomplishments. Some of those reasons include, low concentrations found in water, specific limitations of the methods for pathogen recovery and viability assessment, failure to understand whether ingestion or inhalation pathways are important, and inability to reconcile ecologic risks and human health risks. The inadequate investment in scientific inquiry associated with sources, transport, and fate of contaminants has led to much uncertainty about the most effective risk-reduction management approaches.
Advances in other fields have had important impacts on water science. Nanomaterials, discussed further in Chapters 3 and 4, are a case in point. Although nanomaterials have the opportunity to support novel water-treatment approaches and more efficient disinfection, there is heightened concern about nanoparticles as a contaminant and about the inability to measure and monitor their fate. Nonetheless, nanomaterials may play a role in “tunable” reactive
membranes for desalination, water reuse, and disinfection in the future (Savage and Diallo 2005; Wiesner and Bottero 2007). Various nanostructured catalytic membranes could be used to selectively kill pathogens in drinking water, remove ultratrace contaminants from wastewater for water reuse, or provide bio-active degradation of pharmaceuticals or hormonally active substances from drinking water.
A very basic problem in the near future is how to replace existing, aging infrastructure in the face of a growing population and declining resources. Much of US water and wastewater infrastructure is nearly 100 years old and in dire need of modernization and replacement. The American Society of Civil Engineers grades the US water and wastewater infrastructure as “D-”. It estimates the 5-year investment needed for America’s infrastructure is over $2.2 trillion dollars (ASCE 2009). In some cases, the best designs for replacing current infrastructure may be radically different from the past (decentralized vs. centralized; large built structures vs. small green infrastructure; and low impact development, water reuse, or desalinization). Science and engineering research, coupled with systems-thinking approaches that take account of the numerous implications of water infrastructure, will determine the most cost-effective processes and infrastructure.
Nitrogen and phosphorus are essential nutrients that control the growth of plants and animals. However, problems occur when excess inputs cause large increases in aquatic plant and algal growth and in turn changes in plant and algal species (Bushaw-Newton and Sellner 1999). Decaying algal blooms consume dissolved oxygen, and this leads to hypoxic conditions that are harmful or deadly for many aquatic organisms. Nutrient pollution can cause important economic losses through damage to commercial and recreational fisheries, restrictions on contact-based water recreation, and disamenities (EPA 2012d). Nitrates also pose a human health risk when present at high concentrations in drinking water.
Water-quality conditions reported by states under the Clean Water Act indicate that at least 100,000 miles of rivers and streams; nearly 2.5 million acres of lakes, reservoirs, and ponds; and over 800 square miles of bays and estuaries across the United States are listed as impaired and not meeting state water-quality goals as a result of nitrogen and phosphorus enrichment (EPA 2012a). Only a small fraction of the nation’s total water resources are currently assessed, so those values are underestimates of the spatial extent of nutrient-impaired waters (EPA 2006, 2010a). Diaz and Rosenberg (2008) found that dead zones in the coastal oceans of the world have increased exponentially since the 1960s, and many of them are located along the US Atlantic and Gulf of Mexico coasts. Harmful algal blooms have been reported in virtually all US coastal waters (Bushaw-Newton and Sellner 1999), and symptoms of eutrophication have been found in 78% of the assessed continental US coastal area (Selman et al. 2008).
Excess nutrients reach surface-water resources in direct discharges from point sources (for example, municipal wastewater-treatment plants) and from diffuse non—point 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 fertilizer at the optimal time and rate and then to keep the nutrients in the field. Concomitant 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 denitrification 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 ecosystems 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 effects 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 ecosystem are shared by many other ecosystems, but the differences among them make the required research and the effective tools for addressing the challenges 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 without 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
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 development of policies that can reduce nutrient-pollution problems will require innovative 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 consequences 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 examples in which EPA is already taking steps in this direction with the Chesapeake Bay Program and the New York—New Jersey Harbor Estuary Program. The problem may not be getting progressively worse, but there are still many challenges to attaining further improvements. The prospects are that eutrophication will continue to be a challenge until policies to control nutrients are made more effective (Cary and Migliaccio 2009; Spiertz 2009).
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 diverse 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 Program (NAPAP 1991), which was authorized by Congress in 1980 and informed
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 exacerbate the challenge of meeting health-based air quality standards. Regional long-term approaches for assessment and problem-solving have also been implemented 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 environmental quality occurs even when local investment is large. For example, although 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 anthropogenic 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 Administration, the National Aeronautics and Space Administration, and the National Science 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 expanding 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 implications of different policy options. (The needs for such data are discussed further 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 characteristics reflect substantive changes in the environment, and it is easy to miss important but subtle or slow changes in the environment.
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 approach to understand environmental changes and their effects on human health (see Chapter 4).
|Watershed or Water System||Key Stressors and Issues||EPA Leadership||Science and Engineering Focus|
|Chesapeake Bay, North America's largest estuary (EPA 2012e)||• Eutrophication caused by nutrient Enrichment
• Stressed by pressures of growing
populations, industrial pollution, atmospheric deposition of air pollutants, and conversion of forests to farms and urban areas
|• EPA, Region 3 Mid-Atlantic
• Chesapeake Bay: A Framework
for Action (EPA 1983a,b) provided a framework for additional research and policy initiatives based on the Chesapeake Bay Program, which was established in 1983 as a partnership of the EPA, Maryland, and Virginia
|• Developed a number of innovative tools
• Nitrogen-removal technology at wastewater-treatment plants
• Computer model built to simulate how the massive 64,000-mi2 watershed processes nutrient and sediment allocations
|Everglades, a sub-tropical wetlands watershed Florida, which houses the Everglades National Park (EPA 2007)||• Altered hydrology
• Soil erosion
• One of the most threatened
subtropical preserves in the United States
|• EPA, Region 4
• The Comprehensive Everglades
Restoration Plan is an ambitious, multi-billion-dollar and multi-decadal restoration program involving federal and state governments
• EPA developed the Everglades Ecosystem Assessment Program, which contributes to the joint federal-state Comprehensive Everglades Restoration Plan
|• Aquifer storage and recovery
• Ecosystem restoration
• One of the strongest aspects of the Comprehensive Everglades Restoration Plan science program is its monitoring and assessment program (see, for example, NRC 2003)
• Developed scientific tests, experiments, and physical models
|Great Lakes Basin, the largest transboundary freshwater system in the world (Lakes Erie, Huron, Michigan, Ontario, and Superior and five major connecting rivers: Detroit, Niagara, St. Clair, St. Lawrence, and St. Mary's) (EPA 2011e).||• Climate change associated with lowering lake level
• Invasive species
• Mercury loading (alone and with contaminated sediments)
• Effects on community health, tourism, fisheries, power industry, and grids; human health and ecosystems are seen as being at risk
|• EPA, Region 5
• Great Lakes Restoration Initiative action plan
• A Great Lakes inter-agency task force was formed to coordinate federal and bi-national restoration efforts
|• The largest investment in the Great Lakes in two decades
• Priority “focus areas” were
“1) cleaning up toxics and toxic hot spot areas of concern; 2) combating invasive species; 3) promoting near-shore health by protecting watersheds from polluted run-off; 4) restoring wetlands and other habitats; and 5) tracking progress, education, and working with strategic partners” (MI DNR 2011)
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 factors, 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 systems (such as energy), communities, and other human activities are designed and carried out.
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