www.epa.gov/or
NAL REVIEW DRAFT
OT CITE OR QUOTE
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1 Review Draft EPA/600/R-07/045
2 DO NOT CITE OR QUOTE External Review Draft
3 May 2007
EPA's 2007 Report on the Environment:
Science Report
9
10 NOTICE
11 THIS DOCUMENT IS A PRELIMINARY DRAFT. It has not been formally released by the U.S.
12 Environmental Protection Agency and should not at this stage be construed to represent Agency policy. It
13 is being circulated for comment on its technical accuracy and policy implications.
14
15
16
17
18
19 Office of Research and Development
20 U.S. Environmental Protection Agency
21 Washington, DC
22
23
This document is a draft for review purposes only and does not constitute Agency policy. 1-1
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i ERA'S 2007 REPORT ON THE ENVIRONMENT:
2 SCIENCE REPORT
3 CONTENTS
4 1 Introduction 1-1
5
6 2 Air
7
8 2.1 Introduction 2-5
9 2.2 What are the trends in outdoor air quality and their effects on human health and the
10 environment? 2-9
11 2.3 What are the trends in greenhouse gas emissions and concentrations? 2-93
12 2.4 What are the trends in indoor air quality and their effects on human health? 2-108
13
14 3 Water
15
16 3.1 Introduction 3-6
17 3.2 What are the trends in extent and condition of fresh surface waters and their effects on
18 human health and the environment? 3-11
19 3.3 What are the trends in extent and condition of ground water and their effects on human
20 health and the environment? 3-41
21 3.4 What are the trends in the extent and condition of wetlands and their effects on human
22 health and the environment? 3-50
23 3.5 What are the trends in extent and condition of coastal waters and their effects on human
24 health and the environment? 3-59
25 3.6 What are the trends in the condition of drinking water and their effects
26 on human health? 3-87
27 3.7 What are the trends in the condition of recreational waters and their effects
28 on human health and the environment? 3-96
29 3.8 What are the trends in the condition of consumable fish and shellfish and their
30 effects on human health? 3-99
31
32 4 Land
33
34 4.1 Introduction 4-5
35 4.2 What are the trends in land cover and their effects on human health and
36 the environment? 4-9
37 4.3 What are the trends in land use and their effects on human health and
38 the environment? 4-22
39 4.4 What are the trends in wastes and their effects on human health and the
40 environment? 4-38
41 4.5 What are the trends in chemicals used on the land and their effects on human health
42 and the environment? 4-48
43 4.6 What are the trends in contaminated land and their effects on human health
44 and the environment? 4-67
45
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1 5 Human Health
2
3 5.1 Introduction 5-5
4 5.2 What are the trends in health status in the U.S.? 5-11
5 5.3 What are the trends in human disease and conditions for which environmental pollutants
6 may be a risk factor including across population subgroups and geographic regions? .5-25
7 5.4 What are the trends in exposure to common environmental pollutants including across
8 population subgroups and geographic regions? 5-72
9
10 6 Ecological Condition
11
12 6.1 Introduction 6-5
13 6.2 What are the trends in the extent and distribution of the nation's ecological systems? .6-11
14 6.3 What are the trends in the diversity and biological balance of the nation's ecological
15 systems? 6-29
16 6.4 What are the trends in the ecological processes that sustain the nation's ecological
17 systems? 6-43
18 6.5 What are the trends in the critical physical and chemical attributes and processes of the
19 nation's ecological systems? 6-50
20 6.6 What are the trends in biomeasures of exposure to common environmental pollutants in
21 plants and animals? 6-72
22
23 7 Afterword 7-1
24
25 Appendix A Acronyms and Glossary
26
27 Appendix B Development of EPA's 2007 ROE Science Report
28 Appendix C Comparison of Indicators Used in EPA's 2003 Draft ROE and 2007 ROE
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i 1. INTRODUCTION
2 To accomplish its mission, the U.S. Environmental Protection Agency (EPA) must pay close attention to
3 trends in the condition of the nation's air, water, and land, and related or associated trends in human
4 health and ecological systems. Compiling relevant, scientifically sound data on the status and trends of
5 the nation's environment provides valuable input for developing EPA's strategic outlook and priorities
6 and allows EPA and the public to assess whether the Agency is succeeding in its overall mission to
7 protect human health and the environment.
8 EPA embarked on a bold initiative in 2001 to assemble, for the first time, the most reliable available
9 indicators of national environmental conditions and their trends over time that are important to its
10 mission. EPA initially presented this information in its Draft Report on the Environment (ROE) Technical
11 Document, released in 2003. Since then, EPA has revised, updated, and refined the ROE in response to
12 scientific developments, as well as feedback from EPA's Scientific Advisory Board (SAB) and
13 stakeholders. EPA 's 2007 Report on the Environment: Science Report presents the results of this work.
14 EPA 's 2007 ROE Science Report (SR) compiles in one place, the most reliable indicators currently
15 available that help to answer the questions that EPA believes are of critical importance to its mission and
16 to the national interest. All of the indicators were screened and peer-reviewed to meet exacting standards
17 for accuracy, representativeness, and reliability. This 2007 ROE SR presents trends wherever adequate
18 data are currently available, and it establishes some reliable national baselines where trend data are not
19 yet available. Equally important, the report identifies key limitations of these indicators and gaps where
20 reliable indicators do not yet exist. Data limitations are noted to provide the reader with information about
21 the quality or extent of the data presented that may affect the way in which they are used. Generally, such
22 limitations cause uncertainty in drawing conclusions about actual conditions in the environment. Data
23 gaps are noted to identify areas or aspects of the environment in which little or no measurement is done.
24 This report does not propose actions to reduce data limitations or fill gaps, nor does it analyze the costs
25 and benefits of doing so.
26 Written for environmental professionals, the ROE Science Report provides the scientific basis for two
27 other components of EPA's ROE project:
28 • A web-enabled version, the e-ROE, that provides access to the details of the methodology,
29 databases, references, and sources of additional information behind the indicators that form the
30 basis for the ROE Science Report
31 • EPA Report on the Environment: Highlights of National Trends 2007, which highlights the most
32 important content of the Science Report for the general public.
33 The indicators presented in this report are supported by data gathered from different federal and state
34 agencies and non-government organizations using a variety of methods. EPA is committed to releasing
35 periodic updates of the ROE so that information on environmental condition and trends can be provided
36 on a long-term basis within EPA and to external scientists and interested members of the public.
37 Organization of This Report
38 This report consists of five chapters: Air, Water, Land, Human Health, and Ecological Condition. The
39 Air, Water, and Land chapters (Chapters 2, 3, and 4) focus on trends in air, water, and land media, and
40 their effects on human health and ecological systems. The Human Health and Ecological Condition
41 chapters (Chapters 5 and 6) follow with information on overall trends in human health and ecological
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1 systems. These latter two chapters address questions that are intrinsically affected by multiple factors
2 across media, as described below.
3 For each of these five chapters, EPA identified a set of priority questions (see below) that it considers to
4 be most important and relevant to the Agency's mission to protect the environment and human health.
5 The report is organized around these questions. The response to each of the questions has three
6 components:
7 • An introduction that describes the scope of the question (see below) and provides relevant
8 background information.
9 • A set of indicators that answer (or more often partially answer) the question.
10 • A discussion of (1) the "answer" that the indicators collectively provide to the question; and
11 (2) the most critical indicator gaps, limitations, and challenges that prevent the question from
12 being fully answered.
13 The document concludes with Chapter 7, Afterword, which discusses the next steps for improving
14 indicators and summarizes the challenges to answering the questions and synthesizing and integrating
15 information across indicators. Appendix A lists acronyms and provides a glossary of terms that have
16 particular definitions within this document or whose definitions are not commonly available. Appendix B
17 describes the process used to develop the 2007 ROE Science Report. Appendix C compares indicators
18 used in the 2003 Draft ROE Technical Document with those in this 2007 version.
19 ROE Questions
20 As described above, the ROE is organized around 26 priority questions that EPA considers to be
21 important and relevant to its mission. EPA developed these questions in 2002 and refined them in 2004 in
22 a series of workshops involving specialists from across the Agency. These are questions that EPA
23 believes should be answered with confidence if it is to be adequately informed about important
24 environmental trends. They are not necessarily, however, questions that EPA can fully answer at present
25 based on available data.
26 The questions in the Air, Water, and Land chapters examine trends in the condition, quality, and/or extent
27 of environmental media (e.g., outdoor air, fresh surface waters) and trends in stressors to those media
28 (e.g., pollutant emissions, chemicals used on land). These questions also address trends in human health
29 and ecological systems that are expected to be clearly linked to the foregoing media-related trends. For
30 example, downward trends in the acidity of lakes and streams in certain geologically sensitive regions of
31 the country are expected to be clearly linked to declining acid deposition, and some types of damage to
32 leaves in forest plants can be clearly attributed to ozone exposure. Therefore, these types of effects
33 indicators are presented in these media-specific chapters of this document.
34 The questions in the chapters on Human Health and Ecological Systems, on the other hand, do not
35 explicitly ask about particular effects arising from particular media. At the national or regional scales
36 covered in this report, most trends in human health or in the condition of ecological systems cannot be
37 definitively linked to trends in particular stressors arising from particular media, such as air pollutant
38 emissions or concentrations of contaminants in food or drinking water, because many factors, some
39 having nothing to do with pollutants or particular media, affect the trends in these indicators. For
40 example, the Human Health chapter includes a question about trends in human disease and conditions for
41 which environmental pollutants may be a risk factor, and the Ecological Condition chapter includes
42 questions about trends in biological diversity and critical physical and chemical attributes of ecological
43 systems. Environmental pollutants are known to influence these types of trends, but trends in these health
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1 or ecological outcomes cannot be attributed with any confidence to particular pollutants or other causes..
2 Nevertheless, EPA believes that it is important to ask questions about such trends and to maintain
3 surveillance of related indicators in order to identify emerging issues that may need additional research or
4 investigation.
5 Each chapter is organized into sections, one for each ROE question. Each section begins by discussing the
6 range of issues related to that question that are particularly important to EPA's mission. This includes not
7 only EPA's regulatory responsibilities, but also areas where the Agency conducts or sponsors research,
8 exerts policy leadership, provides information to the public, or shares an interest in human health and the
9 environment with its federal, state, and tribal partners. It is important to note that the ROE does not cover
10 other important environmental issues, such as natural resource management, land management, or the
11 control of communicable diseases, that are more closely related to the missions of other government
12 agencies.
13 ROE Indicators
14 Environmental conditions can be represented in many ways. For particular issues or particular locations,
15 many reports conduct an integrated assessment by gathering and weighing the strengths and weaknesses
16 of all the relevant information available. This integrated approach is not feasible for the ROE because it
17 covers so many different topics across the entire nation. Instead, the ROE relies on an indicator approach.
18 To maintain a high level of scientific integrity and consistency among the indicators used in the ROE,
19 EPA established an explicit definition and six criteria that all ROE indicators must meet (see Box 1-1).
20 The criteria are based in part on EPA's Information Quality Guidelines
21 (http://www.epa.gov/quality/informationguidelines/). which cover important information that EPA
22 provides to the public. Together, the six criteria are intended to ensure that all indicators in the ROE are
23 useful to EPA and the public, and that they are objective, transparent, and based on high-quality,
24 comparable, and representative data across space and time. The ROE emphasizes indicators that can be
25 tracked over time; therefore, one-time studies are not included unless they serve as baselines for future
26 trends.
27 Indicators, whether they represent baseline conditions or trends, involve uncertainties. While statistical
28 analyses have been or could be done on some of the indicators in this report, such analyses require
29 considerably more complex indicator development and peer review. Due to time and resource limitations,
30 EPA determined that this 2007 edition of the ROE Science Report would not include statistical analysis
31 of uncertainty and trends; however, the Agency recognizes that this is an important issue and does plan to
32 quantify uncertainty in indicators in the next edition of the ROE.
33 The ROE indicator definition intentionally excludes some categories of indicators. For example, ROE
34 indicators include measures of pollutant emissions, but not measures of corresponding causal factors such
35 as energy generation or agricultural production. Also excluded are economic indicators such as the value
36 of land or natural resources and the cost of health care or pollution control, or efficiency factors such as
37 pollutant emissions per vehicle mile traveled. Because ROE indicators focus on actual physical
38 measurements, administrative indicators such as permits issued, regulations promulgated, and
39 enforcement actions also are excluded. Indicators based on results predicted by environmental fate and
40 transport models or risks to people or ecological systems also are excluded, because they are not based on
41 actual measurements. Indicators based on emissions factor are necessary exceptions, because most
42 emissions cannot be measured directly.
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Box 1-1. Indicator Definition and Criteria.
Indicator Definition: For EPA 's Report on the Environment, an indicator is a numerical value derived
from actual measurements of a pressure, state or ambient condition, exposure, or human health or
ecological condition over a specified geographic domain, whose trends over time represent or draw
attention to underlying trends in the condition of the environment.
Indicator Criteria:
• The indicator is useful. It answers (or makes an important contribution to answering) a question
in the ROE.
• The indicator is objective. It is developed and presented in an accurate, clear, complete, and
unbiased manner.
• The indicator is transparent and reproducible. The specific data used and the specific
assumptions, analytic methods, and statistical procedures employed are clearly stated.
• The underlying data are characterized by sound collection methodologies, data management
systems to protect its integrity, and quality assurance procedures.
• Data are available to describe changes or trends and the latest available data are timely.
• The data are comparable across time and space, and representative of the target population.
Trends depicted in this indicator accurately represent the underlying trends in the target
population.
2 Selection of the indicators for this 2007 ROE Science Report was conducted internally at EPA, based on
3 indicators suggested by EPA's Program and Regional Offices, and by other federal agencies, state
4 agencies, and non-governmental organizations. As the first step, EPA developed a list of 93 proposed
5 indicators. This included indicators from the 2003 Draft ROE that EPA judged to be relevant and
6 consistent with the ROE 2007 indicator definition and criteria as well as many new indicators (see
7 Appendix C for a list). All proposed indicators were evaluated via an independent public peer review
8 process (see hrt]3://cfi)u^ for detailed information
9 on the peer review). Of the proposed indicators, 86 were ultimately selected for inclusion in the ROE.
10 Appendix B provides more information on the indicator development process.
11 Each indicator consists of graphics or tables and explanatory text. All indicators present the most recent
12 relevant, quality-assured data available when this report went to press. EPA intends to update these
13 indicators in the e-ROE as new data become available. The baselines and reference levels for most
14 indicators follow the underlying sources. Thorough documentation of the indicator data sources can be
15 found at http://cfpub.epa.gov/eroe. For ease of use in both the print and e-versions, each indicator was
16 developed to stand alone, with sufficient information for the reader to understand its scope, origin, and
17 data sources. As a result, some redundancies of text exist in the hardcopy version of the document.
18 Some indicators are used to answer more than one ROE question. In all but one case, these indicators are
19 presented where they are first used to answer a question and referenced when they are used to answer a
20 subsequent question. For example, the Blood Cotinine indicator is first used to answer a question in the
21 Air chapter and then another question in the Health chapter. This indicator is presented in the Air chapter;
22 the Health chapter refers the reader to the Air chapter for details. Tables listing indicators and their page
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1 numbers are provided as navigation aids at the end of this Introduction (Table 1-1), in the introduction to
2 each chapter, and in the introduction to each question.
3
4 More than half the indicators and supporting data derive from sources other than EPA, including other
5 federal agencies, state agencies, and non-government organizations. These external sources also maintain
6 many environmental datasets that are valuable for other purposes and offer potential for development of
7 future ROE indicators (see Box 1-2).
Box 1-2. The Role of Other Important Environmental Datasets
Many important environmental datasets are not included in this report because the data do not yet meet
the ROE indicator criteria. For example, since 1971, the Centers for Disease Control (CDC), EPA, and
the Council of State and Territorial Epidemiologists have maintained a surveillance system for collecting
and periodically reporting data on occurrences and causes of waterborne-disease outbreaks (WBDOs).
State, territorial, and local public health agencies have the primary responsibility for detecting and
investigating WBDOs, and these agencies voluntarily report WBDOs to the CDC and EPA. These
surveillance activities are useful in characterizing the epidemiology of WBDOs, identifying changing
trends in the etiologic agents that caused WBDOs, and determining why the outbreaks occurred. The data
are also useful for identifying major deficiencies in providing safe drinking water. The number and
etiology of WBDOs are reported annually. Results to date range from a high of 53 outbreaks in 1980 to a
low of 8 outbreaks in 2002, with 207 WBDOs and 433,947 illnesses reported in the most recent 12-year
period. Because of the differences in investigating outbreaks, differences in reporting patterns from state
to state, and underreporting, the actual number of WBDOs nationwide is unknown. In addition, outbreaks
represent only a portion of waterborne illness associated with drinking water exposure. Due to these
limitations, the data from this passive surveillance system do not currently meet the indicator criteria for
the ROE. EPA continues to work with CDC and other federal, state, and private organizations on
important programs such as this one, so that they may meet the indicator criteria and be used in future
editions of EPA 's Report on the Environment.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30 The topics of air, water, land, human health, and ecological condition under which the indicators are
31 presented are all interconnected. For example, changes in one medium affect other media, human health
32 depends on environmental condition, and environmental condition is affected by human factors. At the
33 indicator level, the interconnections are complex and multi-factorial. In reality, humans and ecological
34 systems are exposed to multiple pollutants from multiple sources; large spatial and temporal variations in
35 environmental exposures exist; and numerous non-environmental factors may also contribute to an
36 outcome. The ROE recognizes these complexities, and will continue to work in future versions of the
37 ROE and the e-ROE to look for ways to better link and integrate indicators across questions and chapters.
38
39 Regional Indicators
40 The ROE focuses on trends within the United States, even though the indicators may be impacted by
41 sources outside U.S. borders. National-level indicators (indicators for which nationally consistent data are
42 available) are the focus of this report. However, highly aggregated national data may mask important
43 variations that take place at finer scales. Therefore, the ROE takes two preliminary steps to demonstrate
44 how relevant indicators might be identified, developed, and presented at finer geographic scales.
45 • National data are broken out by EPA Regions for 23 indicators where the data are sufficiently
46 representative at that geographic scale. EPA Regions follow state borders, and do not reflect
47 natural boundaries based on physiography, climate, or biota. Rather than adopt
48 regionalization schemes based on natural boundaries that would be unique to each individual
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1
2
3
4
5
6
7
10
11
12
13
14
15
indicator, EPA chose to adopt a consistent approach for all 23 indicators based on EPA
Regions. To aid readers who are unfamiliar with EPA Regional boundaries, the ten EPA
Regions are delineated in Exhibit 1-1, and also depicted in icons on each indicator graphic
that displays regional data.
Ten Regional Indicators (indicators that cover an EPA Region or substantial parts of one or
more EPA Regions) were selected to demonstrate how such indicators can answer part of an
ROE question that is unique to a particular region, or could eventually be expanded to answer
an ROE question at the national level. All Regional Indicators were required to satisfy the
ROE indicator definition and criteria. EPA hopes that these Regional Indicators will serve as
useful models, and that lessons learned from them will help the Agency identify and present a
more robust set of indicators that answer ROE questions at multiple scales in the future.
However, it is important to note that these Regional Indicators are presented as examples
only— they do not represent an exclusive set of indicators needed to answer the ROE
questions at a regional scale, and they may or may not scale up to National Indicators. EPA
may or may not include these indicators in future versions of the ROE.
Exhibit 1-1. The EPA Regions
21
22
23
24
Guam
Trust Territories
American Samoa
Northern Mariana
Islands
16 Changes from 2003 Draft ROE
17 As mentioned earlier, EPA released the first edition of ROE as a draft report in 2003 (see
18 http://www.epa.gov/indicators/roe/html/tsd/index.htm). A number of changes, designed to increase the
19 clarity, consistency, and usefulness of the report, have been incorporated into this 2007 edition in
20 response to comments on the 2003 draft. The major changes comprise:
Indicators - As a result of revisions to the indicator definition and criteria, there have been
several changes to the 2003 indicators, including combining some indicators and deleting others.
Additionally, as mentioned earlier, some new indicators have been added that were not available
for the 2003 version of the report. See Appendix C for details.
777/5 document is a draft for review purposes only and does not constitute Agency policy.
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1 • Spatial Scale - National-level indicators were the focus of the 2003 Draft ROE and continue to
2 be the focus in this 2007 ROE. However, as discussed above under "Regional Indicators," this
3 2007 ROE demonstrates how relevant indicators might be identified, developed, and presented at
4 finer geographic scales in two ways:
5 • Questions and Indicator Placement - The questions in the 2007 report have been revised to
6 present a more consistent format and depth across chapters. In addition, wherever a health or
7 environmental effect is linked predominantly to a single medium (air, water, land), that indicator
8 has been moved from the Human Health or Ecological Condition chapter to the relevant "media"
9 chapter.
10 Conclusion
11 To be effective, policies and programs addressing environmental concerns must be founded in firm
12 scientific understanding of the issues, and adjusted based on monitoring of health and environmental
13 conditions. The Report on the Environment represents a commitment by EPA to continually improve the
14 quality and quantity of information available to understand the condition of human health and the
15 environment and how they are changing over time. Within EPA, this commitment provides ongoing
16 opportunities to use the ROE to inform strategic planning and related activities. The ROE also creates
17 opportunities to establish and strengthen partnerships among federal, state, and non-government
18 organizations for monitoring, data sharing, and data needs planning to support indicator development and
19 improvement.
20 Table 1-1. Chapter Questions and Supporting Indicators.1
Air Chapter
Outdoor Air Quality
What are the trends in outdoor air quality and their effects on human health and the environment?
Carbon Monoxide Emissions
Ambient Concentrations of Carbon Monoxide
Lead Emissions
Ambient Concentrations of Lead
Nitrogen Oxides Emissions
Ambient Concentrations of Nitrogen Dioxide
Volatile Organic Compounds Emissions
Ambient Concentrations of Ozone
Ozone Injury to Forest Plants
Particulate Matter Emissions
Ambient Concentrations of Particulate Matter
Regional Haze
Sulfur Dioxide Emissions
Acid Deposition
Lake and Stream Acidity
Percent of Days with Air Quality Index Values Greater Than 100
Mercury Emissions
Air Toxics Emissions
Ambient Concentrations of Benzene
Concentrations of Ozone-Depleting Substances
Ozone Levels over North America
Ozone and Particulate Matter Concentrations for U.S. Counties in the U.S. /Mexico Border Region
Ambient Concentrations of Manganese Compounds in EPA Region 5
Section
2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
Page
2-9
2-13
2-16
2-19
2-21
2-23
2-26
2-29
2-32
2-37
2-40
2-44
2-50
2-53
2-56
2-62
2-65
2-68
2-70
2-74
2-76
2-79
2-82
2-86
1 As mentioned earlier, some indicators are used to answer more than one question. These indicators are presented
where they are first used to answer a question and referenced under subsequent questions.
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Greenhouse Gases
What are the trends in greenhouse gas emissions and concentrations?
U.S. Greenhouse Gas Emissions
Atmospheric Concentrations of Greenhouse Gases
Indoor Air Quality
What are the trends in indoor air quality and their effects on human health?
U.S. Homes Above EPA's Radon Action Level
Blood Cotinine Level
Water Chapter
Water and Watersheds
What are the trends in extent and condition of fresh surface waters and their effects on human health and the
environment?
High and Low Stream Flows
Streambed Stability in Wadeable Streams
Lake and Stream Acidity
Nitrogen and Phosphorus in Wadeable Streams
Nitrogen and Phosphorus in Streams in Agricultural Watersheds
Nitrogen and Phosphorus Discharge from Large Rivers
Pesticides in Streams in Agricultural Watersheds
Benthic Macroinvertebrates in Wadeable Streams
What are the trends in extent and condition of ground water and their effects on human health and the
environment?
Nitrate and Pesticides in Shallow Ground Water in Agricultural Watersheds
What are the trends in the extent and condition of wetlands and their effects on human health and the
environment?
Wetland Extent, Change, and Sources of Change
What are the trends in extent and condition of coastal waters and their effects on human health and the
environment?
Wetland Extent, Change, and Sources of Change
Trophic State of Coastal Waters
Coastal Sediment Quality
Coastal Benthic Communities
Coastal Fish Tissue Contaminants
Submerged Aquatic Vegetation in the Chesapeake Bay
Hypoxia in the Gulf of Mexico and Long Island Sound
Harmful Algal Bloom Outbreaks Along the Western Florida Coastline
Drinking Water
What are the trends in the condition of drinking water and their effects on human health?
Population Served by Community Water Systems with No Reported Violations of Health-Based Standards
Recreation in and on the Water
What are the trends in the condition of recreational waters and their effects on human health and the
environment?
Consumption of Fish and Shellfish
What are the trends in the condition of consumable fish and shellfish and their effects on human health?
Coastal Fish Tissue Contaminants
Contaminants in Lake Fish Tissue
Land Chapter
Land Cover
What are the trends in land cover and their effects on human health and the environment?
Land Cover
Forest Extent and Type
Land Cover in the Puget Sound/Georgia Basin
2.3
2.3.2
2.3.2
2.4
2.4.2
2.4.2
Section
3.2
3.2.2
3.2.2
2.2.2
3.2.2
3.2.2
3.2.2
3.2.2
3.2.2
3.3
3.3.2
3.4
3.4.2
3.5
3.4.2
3.5.2
3.5.2
3.5.2
3.8.2
3.5.2
3.5.2
3.5.2
3.6
3.6.2
3.7
3.8
3.8.2
3.8.2
Section
4.2
4.2.2
6.2.2
4.2.2
2-93
2-96
2-100
2-108
2-111
2-114
Page
3-11
3-14
3-19
2-62
3-22
3-25
3-28
3-32
3-35
3-41
3-44
3-50
3-53
3-59
3-53
3-62
3-67
3-71
3-103
3-74
3-77
3-81
3-87
3-90
3-96
3-99
3-103
3-107
Page
4-9
4-11
6-14
4-17
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Land Use
What are the trends in land use and their effects on human health and the environment?
Land Use
Urbanization and Population Change
Waste
What are the trends in wastes and their effects on human health and the environment?
Quantity of Municipal Solid Waste Generated and Managed
Quantity of RCRA Hazardous Waste Generated and Managed
Chemicals
What are the trends in chemicals used on the land and their effects on human health and the environment?
Fertilizer Applied for Agricultural Purposes
Toxic Chemicals in Production-Related Wastes Released, Treated, Recycled, or Recovered for Energy Use
Pesticide Residues in Food
Reported Pesticide Incidents
Contaminated Lands
What are the trends in contaminated land and their effects on human health and the environment?
High-Priority Cleanup Sites with No Human Contact to Contamination in Excess of Health- Based Standards
High-Priority Cleanup Sites Where Contaminated Ground Water Is Not Continuing to Spread Above Levels of
Concern
Human Health Chapter
Health Status
What are the trends in health status in the U.S.?
General Mortality
Life Expectancy at Birth
Infant Mortality
Disease and Conditions
What are the trends in human disease and conditions for which environmental pollutants may be a risk factor
including across population subgroups and geographic regions?
Cancer Incidence
Childhood Cancer Incidence
Cardiovascular Disease Prevalence and Mortality
Chronic Obstructive Pulmonary Disease Prevalence and Mortality
Asthma Prevalence
Infectious Diseases Associated with Environmental Exposures or Conditions
Birth Defects Rates and Mortality
Low Birthweight
Preterm Delivery
Human Exposure to Pollutants
What are the trends in exposure to common environmental pollutants including across population subgroups and
geographic regions?
Blood Lead Level
Blood Mercury Level
Blood Cadmium Level
Blood Persistent Organic Pollutants Level
Blood Cotinine Level
Urinary Pesticide Level
Urinary Phthalate Level
Ecological Condition Chapter
Extent and Distribution of Ecological Systems
What are the trends in the extent and distribution of the Nation's ecological systems?
Land Cover
Forest Extent and Type
Forest Fragmentation
Wetland Extent, Change, and Sources of Change
Land Use
4.3
4.3.2
4.3.2
4.4
4.4.2
4.4.2
4.5
4.5.2
4.5.2
4.5.2
4.5.2
4.6
4.6.2
4.6.2
Section
5.2
5.2.2
5.2.2
5.2.2
5.3
5.3.2
5.3.2
5.3.2
5.3.2
5.3.2
5.3.2
5.3.2
5.3.2
5.3.2
5.4
5.4.2
5.4.2
5.4.2
5.4.2
2.4.2
5.4.2
5.4.2
Section
6.2
4.2.2
6.2.2
6.2.2
3.4.2
4.3.2
4-22
4-24
4-31
4-38
4-40
4-43
4-48
4-50
4-54
4-58
4-61
4-67
4-70
4-73
Page
5-11
5-13
5-17
5-19
5-25
5-31
5-35
5-37
5-43
5-48
5-53
5-58
5-62
5-65
5-72
5-76
5-79
5-82
5-85
2-118
5-94
5-100
Page
6-11
4-11
6-14
6-17
3-53
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Urbanization and Population Change
Land Cover in the Puget Sound/Georgia Basin
Ecological Connectivity in EPA Region 4
Relative Ecological Condition of Undeveloped Land in EPA Region 5
Diversity and Biological Balance
What are the trends in the diversity and biological balance of the Nation's ecological systems?
Coastal Benthic Communities
Benthic Macroinvertebrates in Wadeable Streams
Bird Populations
Fish Faunal Intactness
Submerged Aquatic Vegetation in the Chesapeake Bay
Harmful Algal Bloom Outbreaks Along the Western Florida Coastline
Non-Indigenous Species in the Estuaries of the Pacific Northwest
Ecological Processes
What are the trends in the ecological processes that sustain the Nation's ecological systems?
Carbon Storage in Forests
Critical Physical and Chemical Attributes
What are the trends in the critical physical and chemical attributes and processes of the Nation's ecological
systems?
U.S. and Global Mean Temperature and Precipitation
Sea Surface Temperature
High and Low Stream Flows
Streambed Stability in Wadeable Streams
Sea Level
Nitrogen and Phosphorus Discharge from Large Rivers
Nitrogen and Phosphorus in Wadeable Streams
Nitrogen and Phosphorus in Streams in Agricultural Watersheds
Lake and Stream Acidity
Hypoxia in the Gulf of Mexico and Long Island Sound
Exposure to Pollutants
What are the trends in biomarkers of exposure to common environmental pollutants in plants and animals?
Coastal Fish Tissue Contaminants
Ozone Injury to Forest Plants
Contaminants in Lake Fish Tissue
4.3.2
4.2.2
6.2.2
6.2.2
6.3
3.5.2
3.2.2
6.2.2
6.2.2
3.5.2
3.5.2
6.2.2
6.4
6.4.2
6.5
6.5.2
6.5.2
3.2.2
3.2.2
6.5.2
3.2.2
3.2.2
3.2.2
2.2.2
3.5.2
6.6
3.8.2
2.2.2
3.8.2
4-31
4-17
6-20
6-22
6-29
3-71
3-35
6-32
6-34
3-74
3-81
6-37
6-43
6-45
6-50
6-53
6-58
3-14
3-19
6-61
3-28
3-22
3-25
2-62
3-77
6-72
3-103
2-38
3-107
This document is a draft for review purposes only and does not constitute Agency policy.
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CHAPTER 2
AIR
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AIR CHAPTER CONTENTS
2.1 INTRODUCTION 2-5
2.1.1 Overview of the Data 2-6
2.1.2 Organization of This Chapter 2-7
2.2 WHAT ARE THE TRENDS IN OUTDOOR AIR QUALITY AND THEIR EFFECTS ON
HUMAN HEALTH AND THE ENVIRONMENT? 2-9
2.2.1 Introduction 2-9
2.2.2 ROE Indicators 2-11
INDICATOR: Carbon Monoxide Emissions 2-13
INDICATOR: Ambient Carbon Monoxide Concentrations 2-16
INDICATOR: Lead Emissions 2-19
INDICATOR: Ambient Concentrations of Lead 2-21
INDICATOR: Nitrogen Oxides Emissions 2-23
INDICATOR: Ambient Concentrations of Nitrogen Dioxide 2-26
INDICATOR: Volatile Organic Compounds Emissions 2-29
INDICATOR: Ambient Concentrations of Ozone 2-32
INDICATOR: Ozone Injury to Forest Plants 2-37
INDICATOR: Particulate Matter Emissions 2-40
INDICATOR: Ambient Concentrations of Particulate Matter 2-44
INDICATOR: Regional Haze 2-50
INDICATOR: Sulfur Dioxide Emissions 2-53
INDICATOR: Acid Deposition 2-56
INDICATOR: Lake and Stream Acidity 2-62
INDICATOR: Percent of Days with Air Quality Index Values Greater Than 100 2-65
INDICATOR: Mercury Emissions 2-68
INDICATOR: Air Toxics Emissions 2-70
INDICATOR: Ambient Concentrations of Benzene 2-74
INDICATOR: Concentrations of Ozone-Depleting Substances 2-76
INDICATOR: Ozone Levels over North America 2-79
INDICATOR: Ozone and Particulate Matter Concentrations for U.S. Counties in
the U.S./Mexico Border Region 2-82
INDICATOR: Ambient Concentrations of Manganese Compounds in EPA Region
5 2-86
2.2.3 Discussion 2-89
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What These Indicators Say About Trends in Outdoor Air Quality and Their Effects
on Human Health and the Environment 2-89
Limitations, Gaps, and Challenges 2-91
2.3 WHAT ARE THE TRENDS IN GREENHOUSE GAS EMISSIONS AND
CONCENTRATIONS? 2-93
2.3.1 Introduction 2-93
2.3.2 ROE Indicators 2-95
INDICATOR: U.S. Greenhouse Gas Emissions 2-96
INDICATOR: Atmospheric Concentrations of Greenhouse Gases 2-100
2.3.3 Discussion 2-106
What These Indicators Say About Trends in Greenhouse Gas Emissions and
Concentrations 2-106
Limitations, Gaps, and Challenges 2-106
2.4 WHAT ARE THE TRENDS IN INDOOR AIR QUALITY AND THEIR EFFECTS ON
HUMAN HEALTH? 2-108
2.4.1 Introduction 2-108
2.4.2 ROE Indicators 2-110
INDICATOR: U.S. Homes Above EPA's Radon Action Level 2-111
INDICATOR: Blood Cotinine Level 2-114
2.4.3 Discussion 2-118
What These Indicators Say About Trends in Indoor Air Quality and Their Effects on
Human Health 2-118
Limitations, Gaps, and Challenges 2-118
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1 2.1 INTRODUCTION
2 Air provides the oxygen and carbon dioxide needed to sustain human, animal, and plant life on Earth, and
3 the composition of trace gases in the atmosphere plays an important role for the climate. Air pollution can
4 adversely affect these critical functions of the atmosphere in many ways. High levels of air pollution,
5 whether indoors or outdoors, can harm human health by triggering asthma attacks, aggravating allergies,
6 and contributing to or potentially causing various diseases. Certain types of outdoor air pollution can
7 impair visibility and damage other valued resources, such as forests, lakes and streams, and building
8 surfaces. On a global scale, air pollution released worldwide can eventually change the atmosphere's
9 composition with important consequences, including depletion of the Earth's ozone layer and climate
10 change.
11 An important component of EPA's mission is to protect and improve air quality in order to avoid or
12 mitigate the consequences of air pollution's harmful effects. State and tribal air pollution control agencies
13 help fulfill this mission by implementing many of the air pollution control requirements that EPA sets at
14 the federal level. Other federal partners, the academic community, industry and trade associations, and
15 non-government organizations all conduct important research that contributes to the current
16 understanding of regional, national, and global air quality issues.
17 Efforts to maintain good air quality are complicated by population increase, energy consumption, motor
18 vehicle use, and other factors that can lessen air quality. Outdoor air is polluted by emissions from a broad
19 array of industrial and mobile sources, as well as everyday activities like dry cleaning, painting, and
20 refueling vehicles. Emissions from natural sources, such as wildfires, also contribute to outdoor air
21 pollution. Similarly, indoor air quality is affected not only by these outdoor sources, but also by sources
22 found within buildings, such as home heating devices, tobacco smoke, consumer products, and building
23 materials. In this chapter, EPA assesses national trends in the condition of air, stressors that influence air
24 quality, and associated exposures and effects among humans and ecological systems. ROE indicators are
25 presented to address three fundamental questions about the state of the nation's air:
26 • What are the trends in outdoor air quality and their effects on human health and the
27 environment? This question examines a broad spectrum of outdoor air quality issues,
28 including polluted air that people breathe at ground level, deposition of air pollutants to land
29 and water, and depletion of the Earth's ozone layer. For each issue, information is provided
30 both on the main stressors (emission sources) and potential health and environmental effects.
31 • What are the trends in greenhouse gas emissions and concentrations? This question
32 focuses on releases and atmospheric concentrations of certain so-called "greenhouse gases,"
33 or gases in the atmosphere that help regulate Earth's temperature and thus contribute to
34 climate change—a topic introduced in this chapter and revisited in Chapter 6, Ecological
35 Condition.
36 • What are the trends in indoor air quality and their effects on human health ? This question
37 considers air quality in indoor settings, such as homes, offices, and schools, and how poor
38 indoor air quality can affect human health, whether through causing adverse health effects or
39 by impairing productivity.
40 These ROE questions are posed without regard to whether indicators are available to answer them. This
41 chapter presents the indicators available to answer these questions, and also points out important gaps
42 where nationally representative data are lacking.
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1 While this chapter focuses on air quality, readers should not infer that air quality trends are completely
2 independent of the other themes in ROE: Water, Land, Human Health, and Ecological Condition. High
3 levels of air pollution are linked to many broader environmental concerns. Because air interfaces directly
4 with water and land, air pollutants can enter these media through various fate and transport mechanisms,
5 such as wet deposition onto surface waters and gravitational settling onto soils. Conversely, chemicals in
6 surface water and soil can enter outdoor air through processes like evaporation and resuspension of wind-
7 blown dust. Thus, in a very general sense, air quality is related to selected topics covered in the Water
8 Chapter and the Land Chapter. Further, nearly every topic addressed in this chapter is primarily motivated
9 by some specific concern regarding human health or ecological effects. Therefore, air quality and climate
10 change are conceptually linked to many topics addressed in the Human Health and Ecological Condition
11 Chapters. Air quality issues that are connected with other ROE themes are introduced and examined in
12 this chapter, and addressed further in later sections of ROE as appropriate.
13 2.1.1 Overview of the Data
14 When developing the 27 ROE indicators in this chapter, EPA accessed and compiled data collected by
15 many parties. The individual data sources that were evaluated can be classified into four general
16 categories:
17 • National emission inventories. Emissions data were queried from databases known as
18 emission inventories. These inventories are composites of measured and estimated emission
19 rates for industrial sources, mobile sources, and natural sources. Industry and state, tribal, and
20 local agencies provide most of the data compiled in these inventories.
21 • Ground-level ambient air monitoring data. Ambient air concentrations measured at ground
22 level primarily come from measurements collected in a nationwide network of ambient air
23 monitoring stations (i.e., State and Local Air Monitoring Stations, National Air Monitoring
24 Stations). State, tribal, and local agencies operate most of these stations and submit their
25 validated measurement results to a centralized database.
26 • Deposition measurements. Representative data on deposition of outdoor air pollutants come
27 from samples collected and analyzed at fixed locations throughout the country as part of the
28 National Atmospheric Deposition Program and the Clean Air Status and Trends Network.
29 • Other data sources. The remaining ROE indicators in this chapter draw from various other
30 data sources, including satellite measurements of stratospheric ozone depletion, an evaluation
31 of pollution-related injury to forest plants, surveys on radon in homes and evidence of
32 exposure to environmental tobacco smoke, an inter-agency assessment of regional haze, and
33 articles in the peer-reviewed literature on historical concentrations of greenhouse gases
34 estimated from ice core samples.
35 Tracking the country's air quality is a complicated endeavor and cannot be done with any single indicator.
36 Multiple indicators are needed to characterize indoor air quality separately from outdoor air quality, air
37 quality trends at ground level separately from changing atmospheric conditions aloft, and air pollution
38 levels for the many different pollutants of potential concern. Regardless of the issue of interest, a
39 particular challenge in developing this chapter's indicators is that air quality can vary considerably with
40 location and time. Consequently, all underlying data sources must be sufficiently representative, both
41 spatially and temporally.
42 Spatial resolution is a critical consideration due to associated spatial variations in population density,
43 industrial emissions sources, traffic patterns, and meteorological conditions that dictate relevant
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1 atmospheric fate and transport processes. Temporal resolution also must be considered because ambient
2 air concentrations of certain pollutants vary considerably with time of day (due to sunlight's contribution
3 to photochemical reactions), day of week (due to commuting patterns), and season (due to changes in
4 meteorological conditions). Temporal resolution is particularly important when interpreting air quality
5 trends, because sufficiently long time frames often must be considered to ensure that trends reflect actual
6 changes in air quality, rather than natural fluctuations in atmospheric conditions.
7 This chapter presents only data that meet the ROE indicator definition and criteria (see Chapter 1,
8 Introduction). Note that non-scientific indicators, such as administrative and economic indicators, are not
9 included in this definition. Thorough documentation of the indicator data sources and metadata can be
10 found online at [INSERT URL]. All indicators were peer-reviewed during an independent peer review
11 process (see [INSERT URL] for more information). Readers should not infer that the indicators included
12 reflect the complete state of knowledge on the nation's air. Many other data sources, publications, and
13 site-specific research projects have contributed substantially to the current understanding of air quality
14 trends, but are not used in this report because they did not meet some aspect of the ROE indicator criteria.
15 2.1.2 Organization of This Chapter
16 This chapter's remaining three sections are framed around the three overarching questions that EPA seeks
17 to answer about trends in air. Each section introduces the question and its importance, presents the
18 National Indicators that help answer the question, and discusses what these indicators, taken together, say
19 about the question. The chapter also presents two Regional Indicators that meet the ROE indicator
20 definition and criteria and help to answer a question at a smaller geographic scale. Each section concludes
21 by listing major challenges to answering the questions and identifying important data gaps.
22 The table on the next page lists the indicators used to answer the three questions in this chapter and shows
23 the locations where the indicators are presented.
24
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Table 2.1.1. Air—ROE Questions and Indicators
Question
What are the trends in
outdoor air quality and
their effects on human
health and the
environment?
What are the trends in
greenhouse gas
emissions and
concentrations ?
What are the trends in
indoor air quality and
their effects on human
health?
Indicator Name
Carbon Monoxide Emissions (N/R)
Ambient Concentrations of Carbon Monoxide
(N/R)
Lead Emissions (N)
Ambient Concentrations of Lead (N)
Nitrogen Oxides Emissions (N/R)
Ambient Concentrations of Nitrogen Dioxide
(N/R)
Volatile Organic Compounds Emissions (N/R)
Ambient Concentrations of Ozone (N/R)
Ozone Injury to Forest Plants (N/R)
Particulate Matter Emissions (N/R)
Ambient Concentrations of Particulate Matter
(N/R)
Regional Haze (N)
Sulfur Dioxide Emissions (N/R)
Acid Deposition (N)
Lake and Stream Acidity (N)
Percent of Days with Air Quality Index Values
Greater Than 100 (N/R)
Mercury Emissions (N)
Air Toxics Emissions (N/R)
Ambient Concentrations Benzene (N)
Concentrations of Ozone-Depleting Substances
(N)
Ozone Levels over North America (N)
Ozone and Particulate Matter Concentrations for
U.S. Counties in the U.S./Mexico Border
Region (R)
Ambient Concentrations of Manganese
Compounds in EPA Region 5 (R)
U.S. Greenhouse Gas Emissions (N)
Atmospheric Concentrations of Greenhouse
Gases (N)
U.S. Homes Above EPA's Radon Action Level
(N)
Blood Cotinine Level (N)
Section
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
2.2.2
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2-19
2-21
2-23
2-26
2-29
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2-44
2-50
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2-56
2-62
2-65
2-68
2-70
2-74
2-76
2-79
2-82
2-86
2.3.2
2.3.2
2-96
2-100
2.4.2
2.4.2
2-111
2-114
2
3
4
5
N = National Indicator
R = Regional Indicator
N/R = National Indicator displayed at EPA Regional scale
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1 2.2 WHAT ARE THE TRENDS IN OUTDOOR AIR QUALITY AND THEIR EFFECTS
2 ON HUMAN HEALTH AND THE ENVIRONMENT?
3 2.2.1 Introduction
4 Outdoor air—the air outside of buildings, from ground level to several miles above the Earth's surface—
5 is a valuable resource for current and future generations because it provides essential gases to sustain life
6 and it shields the Earth from harmful radiation. Air pollution can compromise outdoor air quality in many
7 ways. Outdoor air pollution, for instance, is associated with various adverse health effects including
8 asthma attacks and cancer; and outdoor air pollution can contribute to "smog" and "acid rain," damage
9 crops and surfaces of treasured buildings and monuments, and diminish the protective ozone layer in the
10 upper atmosphere. Maintaining clean air is a challenging task, especially considering the growing
11 stressors on outdoor air quality such as increased population growth, increased use of motor vehicles, and
12 increased energy consumption.
13 Outdoor air pollution contains numerous substances of both natural and anthropogenic origin. While
14 natural sources release some potentially harmful substances into the air (e.g., pollen, mold spores, dust),
15 emissions sources of anthropogenic origin are of particular interest because regulatory and voluntary
16 reductions can lead to decreased emissions and associated air quality improvements. Accordingly, this
17 section focuses on outdoor air quality issues caused at least in part by human activity and acknowledges
18 and quantifies contributions from natural sources, as appropriate.
19 Most outdoor air pollution issues can be traced back to emissions sources that release pollutants into the
20 air. Emissions sources are typically classified into different categories, such as point sources (e.g., power
21 plants, industrial facilities), area sources (e.g., air pollution sources over a diffuse area, such as gasoline
22 stations, dry cleaners, and waste treatment facilities), mobile sources (e.g., cars, trucks, airplanes, off-road
23 vehicles), and natural sources (e.g., wildfires, wind-blown dust, volcanoes). Once pollutants are airborne,
24 prevailing wind patterns carry them from their sources to downwind locations, and pollutants disperse in
25 air as they mix in the atmosphere. Depending on their chemical and physical properties, some pollutants
26 deposit to the Earth's surface near their corresponding emissions sources, while others remain airborne
27 for hours, days, or years. Deposition of air pollutants, especially those that are persistent and
28 bioaccumulative, can lead to accumulation of contaminants in other media. The levels of air pollution at a
29 given location and at a given time are influenced by emissions from nearby and distant sources as well as
30 by atmospheric factors, such as meteorology.
31 Human exposure to outdoor air pollution is a function of the composition and magnitude of air pollution,
32 combined with human activity patterns. Whether people are harmed by poor air quality depends on
33 exposure doses and durations, individuals' susceptibilities to diseases, and other factors. Similarly, air
34 pollutants' interactions with ecosystems determine whether air pollution causes harmful environmental
35 effects. For a complete understanding of a given air pollution issue, information is therefore typically
36 sought on emissions sources, ambient air concentrations, exposures, and effects.
37 Outdoor air pollution can contain hundreds of different pollutants, which are typically grouped into
38 various categories based on shared attributes. Some categories are defined by pollutants' physical
39 attributes (e.g., gases, aerosols, particulates), while others by regulatory terminology (e.g., criteria
40 pollutants, air toxics). The indicators used to answer the question regarding outdoor air quality are
41 organized into the following three categories, which were selected based on the different parts of the
42 atmosphere to which they pertain and the different types of information available to support indicator
43 development:
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1 • Criteria Pollutants. The following six common pollutants are referred to as criteria
2 pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter of different
3 size fractions, and sulfur dioxide. For each criteria pollutant, EPA has established National
4 Ambient Air Quality Standards (NAAQS) to protect public health and the environment.
5 Extensive data are available on criteria pollutants' emissions (or emissions of the pollutants'
6 precursors) and ambient concentrations.
7 • Air Toxics and Other Air Pollutants. Air toxics, also known as hazardous air pollutants, are
8 known or suspected to cause cancer and are associated with other serious health effects, such
9 as reproductive effects or birth defects, or adverse environmental effects. The Clean Air Act
10 specifically identifies 188 air toxics. Numerous other air pollutants exhibit toxicity even
11 though they are not classified as air toxics; included among these other pollutants are several
12 hundred additional chemicals whose emissions are tracked in EPA's Toxics Release
13 Inventory.
14 • Stratospheric Ozone Issues. The ozone layer occurs in the stratosphere between 6 and 20
15 miles above the Earth's surface and protects the Earth's biota from harmful effects of the
16 sun's ultraviolet radiation. Past and ongoing releases of a number of synthetic chemicals from
17 throughout the world have depleted the ozone layer, allowing more ultraviolet radiation to
18 reach the Earth's surface. This can lead to increased incidence of skin cancer, cataracts, and
19 other health problems.1 Further, high levels of ultraviolet radiation can cause detrimental
20 ecological effects, such as stressing productivity of marine phytoplankton, which are essential
21 components of the oceanic food web.2
22 Air pollution is manifest over a range of spatial and temporal domains—an important factor to consider
23 when evaluating trends for the three categories considered in this section. The spatial domains of air
24 pollution issues vary widely. Air pollution can be local in nature. For instance, ambient concentrations of
25 benzene tend to be greatest in the proximity of major sources (e.g., oil refineries, chemical production
26 facilities) and in high-traffic areas; long-range transport is relatively unimportant due to benzene's high
27 photochemical reactivity. Air pollution can also extend over regional and national scales. For example,
28 emissions sources hundreds of miles away can contribute to airborne fine particulate matter at a given
29 location.3 Finally, a few air pollution issues are global in nature. Stratospheric ozone depletion, for
30 example, is affected by releases of ozone-depleting substances from countries worldwide. The spatial
31 domains ultimately determine the minimum spatial resolution of monitors needed to adequately
32 characterize trends.
33 Temporal scales also vary among pollutants and typically reflect some combination of changes in
34 emissions and fluctuations in weather. Ambient air concentrations of some air pollutants, like ground-
35 level ozone, have considerable diurnal and seasonal variations.4 However, temporal variations are far less
1 World Meteorological Organization, et al. 2003. Scientific assessment of ozone depletion: 2002. Geneva,
Switzerland.
2 DeMora, S., S. Demers, and M. Vernet. 2000. The effects of UV radiation in the marine environment. Cambridge,
United Kingdom: Cambridge University Press.
3 U.S. EPA. 2004. The particle pollution report: current understanding of air quality and emissions through 2003.
EPA/454/R-04/002. Research Triangle Park, NC.
4 U.S. EPA. 2004. The ozone report: measuring progress through 2003. EPA/454/K-04/001. Research Triangle Park,
NC.
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1 pronounced for pollutants that are long-lived in the atmosphere, including many ozone-depleting
2 substances. Temporal variations largely determine the appropriate monitoring frequency for quantifying
3 trends and the most meaningful statistic (or averaging time) used to report ambient air concentrations.
4 When quantifying and interpreting long-term trends in outdoor air quality, attention also must be paid to
5 changes in emissions estimation techniques and advances in ambient air monitoring technologies. Unless
6 otherwise noted, the outdoor air quality indicators only come from data sets generated using consistent
7 methodologies over the entire time frame of interest.
8 The nationwide air quality trends in this section are generally consistent with those documented in other
9 EPA publications, though readers should not expect to find perfect concordance among individual data
10 points. This is because some publications address different spatial domains or time frames and may use
11 less rigorous selection criteria when identifying and compiling data sets.
12 2.2.2 ROE Indicators
13 The 23 outdoor air quality indicators track emissions, ambient concentrations, and pollution-related
14 effects over varying spatial domains and time spans, depending on the availability of underlying data. The
15 indicators include 21 National Indicators (12 of which break national data down into the 10 EPA Regions)
16 and 2 Regional Indicators. The most extensive temporal coverage of these indicators tracks trends from
17 1965 to the present.
18 Indicators were developed using data compiled from multiple sources. Emissions indicators are based on
19 EPA's National Emissions Inventory (NEI), a database of measured and estimated emissions for
20 numerous pollutants and source categories. At the writing of this report, NEI data were available from
21 1990 to 2002, but the indicators only present data for those inventory years that are fully updated and are
22 developed using consistent methodologies. Ground-level ambient air concentration indicators were
23 developed from data in EPA's Air Quality System (AQS), a clearinghouse of validated ambient air
24 monitoring results submitted largely by tribal, state, and local environmental agencies. The ambient
25 concentration indicators present data through calendar year 2004, which is the most recent calendar year
26 having a complete, validated set of monitoring data available from AQS when this report was prepared.
27 Remaining indicators draw from different monitoring programs, including regional haze data from the
28 Interagency Monitoring of Protected Visual Environments, acid deposition measurements from the multi-
29 agency National Atmospheric Deposition Program and Clean Air Status and Trends Network, ozone
30 injury observations from the U.S. Forest Service's Forest Health Monitoring Program, and monitoring of
31 stratospheric ozone levels and concentrations of ozone-depleting substances conducted by the National
32 Oceanic and Atmospheric Administration.
33 Table 2.2.1 shows how indicators are classified into three general categories (criteria pollutants, air toxics
34 and other pollutants, stratospheric ozone issues) and then further organized by pollutant. For each
35 pollutant and to the extent supported by ROE indicators, relevant emissions indicators are presented first,
36 immediately followed by ambient concentration indicators, and next by effects indicators. With this
37 organization, readers can readily compare relevant trends in emissions, ambient concentrations, and
38 effects for the same pollutant.
39
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1 Table 2.2.1. ROE Indicators of Trends in Outdoor Air Quality and Their Effects on Human Health
2 and the Environment
NATIONAL INDICATORS
Criteria Pollutants and Their Precursors
Carbon Monoxide Emissions (N/R)
Ambient Concentrations of Carbon Monoxide (N/R)
Lead Emissions
Ambient Concentrations of Lead
Nitrogen Oxides Emissions (N/R)
Ambient Concentrations of Nitrogen Dioxide (N/R)
Volatile Organic Compounds Emissions (N/R)
Ambient Concentrations of Ozone (N/R)
Ozone Injury to Forest Plants (N/R)
Particulate Matter Emissions (N/R)
Ambient Concentrations of Particulate Matter (N/R)
Regional Haze
Sulfur Dioxide Emissions (N/R)
Acid Deposition
Lake and Stream Acidity
Percent of Days with Air Quality Index Values Greater Than 100
(N/R)
Air Toxics and Other Air Pollutants
Mercury Emissions
Air Toxics Emissions (N/R)
Ambient Concentrations of Benzene
Stratospheric Ozone Issues
Concentrations of Ozone-Depleting Substances
Ozone Levels over North America
REGIONAL INDICATORS
Ozone and Particulate Matter Concentrations for U.S. Counties in the
U.S./Mexico Border Region
Ambient Concentrations of Manganese Compounds in EPA Region 5
LOCATION
2.2.2 -p. 2-13
2.2.2 -p. 2-16
2.2.2 -p. 2-19
2.2.2 -p. 2-21
2.2.2 -p. 2-23
2.2.2 -p. 2-26
2.2.2 -p. 2-29
2.2.2 -p. 2-32
2.2.2 -p. 2-37
2.2.2 -p. 2-40
2.2.2 -p. 2-44
2.2.2 -p. 2-50
2.2.2 -p. 2-53
2.2.2 -p. 2-56
2.2.2 -p. 2-62
2.2.2 -p. 2-65
2.2.2 -p. 2-68
2.2.2 -p. 2-70
2.2.2 -p. 2-74
2.2.2 -p. 2-76
2.2.2 -p. 2-79
LOCATION
2.2.2 -p. 2-82
2.2.2 -p. 2-86
N/R = National Indicator displayed at EPA Regional scale
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INDICATOR: Carbon Monoxide Emission:
2 Carbon monoxide (CO) gas forms primarily when carbon fuels are not burned completely. Mobile
3 sources account for the majority of CO emissions (U.S. EPA, 2003). These sources include both on-road
4 vehicles (e.g., cars, trucks, motorcycles) and nonroad vehicles and engines (e.g., farm equipment,
5 construction equipment, aircraft, and marine vessels). Consequently, high concentrations of CO generally
6 occur in areas with heavy traffic congestion. In cities, as much as 95 percent of all CO emissions may
7 come from automobile exhaust (U.S. EPA, 2003). Other sources of CO emissions include industrial
8 processes, non-transportation fuel combustion, and natural sources, such as wildfires. Fuel-burning
9 appliances also are a large source of CO releases in indoor environments. Undetected releases of carbon
10 monoxide in indoor settings can present serious health risks to building occupants. The CO
11 Concentrations indicator (p. 2-16) describes health hazards associated with inhaling CO.
12 This indicator presents CO emissions from traditionally inventoried anthropogenic source categories:
13 1) "Fuel combustion," which includes emissions from coal, gas and oil-fired power plants, industrial,
14 commercial, and institutional sources, as well as residential heaters (e.g., wood-burning stoves) and
15 boilers; 2) "Industrial and other processes," which includes chemical production, petroleum refining, and
16 metals production; 3) "On-road vehicles" which includes cars, trucks, buses, and motorcycles; and
17 4) "Nonroad vehicles and engines," such as farm and construction equipment, lawnmowers, chainsaws,
18 boats, ships, snowmobiles, aircraft, and others. The indicator also includes estimates of biogenic CO
19 emissions in 2002 which were obtained using the Biogenic Emissions Inventory System (BEIS) Model,
20 Version 3.12.
21 CO emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite of
22 data from many different data sources, including industry and numerous state, tribal, and local agencies.
23 Different data sources use different data collection methods, and many of the emissions data are based on
24 estimates rather than actual measurements. For most fuel combustion sources and industrial sources,
25 emissions are estimated using emission factors. Emissions from on-road and nonroad sources were
26 estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
27 NEI data have been collected since 1990 and cover all 50 states and their counties, B.C., the U.S.
28 territories of Puerto Rico and Virgin Islands, and some of the territories of federally-recognized American
29 Indian nations. Data are presented for 1990 and from 1996 to 2002; prior to 1996, only the 1990 data have
30 been updated to be comparable to the more recent inventories.
31 What the Data Show
32 Only CO emissions from anthropogenic sources are included in the NEI. However, CO emissions from
33 biogenic sources were estimated for 2002 to provide a sense of the relative contributions of natural versus
34 anthropogenic emissions (Exhibit 2-1, panel B). Nationally, biogenic emissions were estimated to
35 contribute approximately 5 percent to the CO emissions from all sources during 2002.
36 Nationwide estimated anthropogenic CO emissions have decreased 33 percent between 1990 and 2002,
37 the most recent year for which aggregate NEI emissions estimates are available (Exhibit 2-1, panel A).
38 Almost the entire emissions reduction is attributed to decreased emissions from on-road mobile sources.
39 In 2002, mobile sources (both on-road and nonroad sources combined) accounted for 91 percent of the
40 nation's total anthropogenic CO emissions. The CO emissions reductions are reflected in corresponding
41 reductions in ambient concentrations (the CO Concentrations indicator, p. 2-16).
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Exhibit 2-1. CO emissions in the U.S. by
source category, 1990 and 1996-2002
A. Anthropogenic CO emissions by source category9
Exhibit 2-2. CO emissions in the U.S. by
EPA Region, 1990 and 1996-2002"
Fuel combustion
Other industrial processes
On-road vehicles
Nonroad vehicles and engines
30
25
'90
'96 '97
'99 '00 '01 '02
Year
B. Relative amounts of CO
emissions from anthropogenic
and biogenic sources, 2002
Biogenic
~ 20
o
I 15
1 10
5
0
-R1
—R2
-R3
-R4
-R5
—R6
—R7
R8
—R9
—R10
'90 '96 '97 '98 '99 '00 '01 '02
Year
"Data are presented for 1990 EPA Regions
and 1996-2002, as datasets
from these inventory years are
all fully up-to-date. Data are
available for inventory years
1991-1995, but these data have
not been updated to allow
comparison with data from
1990 and 1996-2002.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
aData are presented for 1990
and 1996-2002, as datasets
from these inventory years
are fully up-to-date. Data are
available for inventory years
1991-1995, but these data
have not been updated to
allow comparison with data
from 1990 and 1996-2002.
Data source: U.S. EPA,
National Emissions
Inventory (NEI), 2005
2 Net estimated anthropogenic CO emissions declined in all EPA Regions between 1990 and 2002 (Exhibit
3 2-2). The largest decrease (8.95 million pounds) occurred in Region 5, and the smallest decrease (1.74
4 million pounds) occurred in Region 8.
5 Indicator Limitations
6
7
8
9
10
11
12
13
14
15
16
17
18
Comparable CO emissions estimates through the NEI are available only for 1990 and 1996-
2002. Data for 1991-1995 are not provided due to differences in emission estimation
methodologies from other inventory years which could lead to improper trend assessments.
CO emissions from "miscellaneous sources," including wildfires, are not included in the total
emissions. Yearly fluctuations in wildfire emissions have the potential to mask trends in
anthropogenic emissions and therefore have been excluded from the trends graphics. Details
on emissions from miscellaneous sources can be found at
http: //www. epa. gov/ttn/chief/eiinformation .html.
The emissions data for CO are largely based on estimates that employ emission factors
generated from empirical and engineering studies, rather than on actual measurements of CO
emissions. Although these estimates are generated using well-established approaches, the
estimates have uncertainties inherent in the emission factors and emission models used to
represent sources for which emissions have not been directly measured.
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1 • The methodology for estimating emissions is continually reviewed and is subject to revision.
2 Trend data prior to any revisions must be considered in the context of those changes.
3 • Not all states and local agencies provide the same data or level of detail for a given year.
4 Data Sources
5 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
6 based on raw CO emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
7 (http://www.epa.gov/ttn/chief/net/2002inventory .html). This indicator aggregates the raw NEI data by
8 source type (anthropogenic or biogenic), source category, and EPA Region.
9 References
10 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
11
12
13 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
14
16
17 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
18 EPA/454/R-03/005. Research Triangle Park, NC.
19
20
21
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INDICATOR: Ambient Carbon Monoxide Concentrations
2 Carbon monoxide (CO) gas forms primarily when carbon fuels are not burned completely. Elevated
3 ambient air concentrations of CO are hazardous because inhaled CO enters the bloodstream and reduces
4 the amount of oxygen that the blood can deliver to the body's organs and tissues. If exposure
5 concentrations are high enough, potentially serious cardiovascular and neurological effects can result.
6 Visual impairment, reduced work capacity, reduced manual dexterity, poor learning ability, and difficulty
7 in performing complex tasks are all associated with exposure to elevated CO levels (U.S. EPA, 2000).
8 Motor vehicle exhaust currently accounts for the majority of CO emissions nationwide, and as much as 95
9 percent of CO emissions in cities with high traffic congestion. Other anthropogenic emissions sources of
10 CO include fossil fuel combustion for heating and power generation, metals processing, and chemical
11 manufacturing. The highest ambient air concentrations of CO often occur during nighttime inversion
12 conditions, which trap pollutants near ground level. These conditions are most frequently observed during
13 the cold winter months (U.S. EPA, 2003).
14 This indicator presents ambient CO concentrations in parts per million (ppm) from 1980 to 2004, based
15 on continuous measurements averaged over 8-hour time frames. The 8-hour standard is indicative of
16 exposures occurring over a sustained period of time, for example, an outdoor worker's exposure over the
17 course of a work day. This indicator displays trends in the second highest annual 8-hour average CO
18 concentrations for 160 sites that have consistent data for the period of record in the National Air
19 Monitoring Stations (NAMS), State and Local Air Monitoring Stations (SLAMS) network, and other
20 special purpose monitors. It also shows trends in the average 8-hour measurements in each EPA Region.
21 This indicator's exhibits display the National Ambient Air Quality Standard (NAAQS) for CO as a point
22 of reference, but the fact that the national or any regional 8-hour values fall below the standard does not
23 mean that all monitoring sites nationally or in the EPA Region also are below the standard. The indicator
24 displays trends in the number of the 160 sites nationwide at which CO concentrations exceeded the 8-hour
25 standard, but this statistic is not displayed for each EPA Region.
26 What the Data Show
27 The 2004 CO concentration averaged across 160 monitoring sites nationwide was 72 percent lower than
28 that for 1980, and is the lowest level recorded during the past 25 years (Exhibit 2-3, panel A). The
29 downward trend in CO concentrations in the 1990s parallels the downward trend observed in CO
30 emissions, which has been attributed largely to decreased emissions from mobile sources (the CO
31 Emissions indicator, p. 2-13). In addition, of the 160 sites comprising this trend (out of 425 total
32 monitoring sites that were operating in 2004), the number reporting CO concentrations above the CO
33 standard declined to zero over the same period (Exhibit 2-3, panel B).
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Exhibit 2-3. Ambient CO concentrations in the
U.S., 1980-2004"
16
|~ 14
|f 12
-|1 10
l| «
|l 6
It 4
I" 2
0
A. Ambient concentrations
90% of sites have concentrations below this line
or
NAAQS = 9 ppm
10% of sites have
concentrations below this line
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
it60
B. Number of trend sites above NAAQS
ll
50
ii 30
§ 20
i
10
£ ^
| £ '80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
z oo Year
"Coverage: 160 monitoring sites nationwide (out of a total of 425
sites measuring CO in 2004) that have sufficient data to assess CO
trends since 1980.
Data source: U.S. EPA, Air Quality System, 2005
Exhibit 2-4. Ambient CO concentrations in the
contiguous U.S. by EPA Region, 1980-2004"
ll
NAAQS = 9 ppm
— R1
— R2
-R3
-R4
—R5
-R6
—R7
R8
-R9
-R10
—Nat'l
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
"Coverage: 155 monitoring sites
in the EPA Regions (out of a total
of 425 sites measuring CO in
2004) that have sufficient data to
assess CO trends since 1980.
Data source: U.S. EPA, Air
Quality System, 2005
Also shown on Exhibit 2-3 (panel A) are the 90th
and 10th percentiles based on the distribution of
annual statistics at the monitoring sites. This
provides additional graphical representation of the
distribution of measured concentrations across the
monitoring sites for a given year. Thus, the graphic
displays the concentration range where 80 percent
of measured values occurred for that year.
9 Consistent with the nationwide trend, CO levels in all ten EPA Regions have steadily decreased since
10 1980, with percent reductions over this period ranging from 64 percent (Region 4) to 80 percent (Region
11 1) (Exhibit 2-4).
12 Indicator Limitations
13
14
15
16
17
18
19
20
• Because most CO monitoring sites are located in high-traffic urban areas, the nationwide
trends presented in this indicator might not accurately reflect conditions outside the
immediate urban monitoring areas.
• Because of the relatively small number of trend sites in some EPA Regions, the regional
trends are subject to greater uncertainty than the national trends. Some EPA Regions with low
average concentrations may include areas with high local concentrations, and vice versa.
• To ensure that long-term trends are based on a consistent set of monitoring sites, selection
criteria were applied to identify the subset of CO monitoring sites with sufficient data to
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1 assess trends since 1980. Monitoring sites without sufficient data are not included in the trend
2 analysis. Some excluded monitoring sites reported CO concentrations above the CO standard
3 over the time frame covered by this indicator.
4 Data Sources
5 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
6 based on raw CO ambient air monitoring data in EPA's Air Quality System (AQS) (U.S. EPA, 2006)
7 (http://www.epa.gov/ttn/airs/airsaqs/). National and regional trends in this indicator are based on the
8 subset of CO monitoring stations that have sufficient data to assess trends since 1980.
9 References
10 U.S. EPA. 2006. Data from the Air Quality System. Accessed 2006.
11
12 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
13 EPA/454/R-03/005. Research Triangle Park, NC.
14 U.S. EPA. 2000. Air quality criteria for carbon monoxide, 2000. EPA/600/P-99/001F. Research Triangle
15 Park,NC.
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INDICATOR: Lead Emissions
2 Lead is a naturally occurring metal found in small amounts in rock and soil. Lead has been used
3 industrially in the production of gasoline, ceramic products, paints, metal alloys, batteries, and solder. In
4 the past, automotive sources were the major contributors of lead emissions to the atmosphere. After
5 leaded motor vehicle fuels were phased out during the 1970s and 1980s, the contribution of air emissions
6 of lead from the transportation sector, and particularly the automotive sector, greatly declined. Today,
7 industrial processes, primarily metals processing, account for a large portion of lead emissions to the
8 atmosphere and the highest levels of airborne lead are usually found near industrial operations that
9 process materials containing lead, such as smelters (U.S. EPA, 2003). Exposure to lead occurs mainly
10 through inhalation of air and ingestion of lead in food, water, soil, or dust. The Lead Concentrations
11 indicator (p. 2-21) describes health hazards associated with lead exposures.
12 This indicator presents lead emissions from traditionally inventoried anthropogenic source categories:
13 1) "Fuel combustion," which includes emissions from coal, gas and oil-fired power plants, industrial,
14 commercial, and institutional sources, as well as residential heaters and boilers; 2) "Other sources," which
15 include chemical production and petroleum refining; 3) "On-road vehicles," which includes cars, trucks,
16 buses, and motorcycles; 4) "Nonroad vehicles and engines," such as farm and construction equipment,
17 lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft, and others; and 5) "Metals industrial
18 processing." Since metals processing is one of the largest sources of lead emissions, the indicator includes
19 a metals source category in addition to the four categories presented in the other emissions indicators.
20 For the years 1970 through 1985, the primary source for lead emissions data was the National Emissions
21 Data System (NEDS) archives. Since 1990, lead emissions data have been tracked by the National
22 Emissions Inventory (NEI). The NEI is a composite of data from many different data sources, including
23 industry and numerous state, tribal, and local agencies. Different data sources use different data collection
24 methods, and many of the emissions data are based on estimates rather than actual measurements. For
25 most industrial processes and fuel combustion sources, emissions are estimated using emission factors.
26 Emissions from on-road and nonroad sources were estimated using EPA-approved modeling approaches
27 (U.S. EPA, 2005).
28 Data for lead emissions cover all 50 states and their counties, D.C., the U.S. territories of Puerto Rico and
29 Virgin Islands, and some of the territories of federally-recognized American Indian nations.
30 What the Data Show
31 Between 1970 and 2002, estimated nationwide lead emissions decreased by 99 percent (219,350 tons),
32 mostly due to reductions from on-road vehicle sources after lead was removed from gasoline (Exhibit 2-
33 5). Since 1990, further declines in lead emissions occurred, mostly due to reductions from on-road
34 vehicles, nonroad vehicles and engines, and metals industrial processing . Sharp declines in nationwide
35 air concentrations of lead between 1980 and 1990 paralleled the emissions reductions (the Lead
3 6 Concentrations indicator, p. 2-21).
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Exhibit 2-5. Lead emissions in the U.S. by
source category, 1970-1999 and 2002a
Indicator Limitations
•c- 250
§.200
150
o 100
50
D Other sources
D Nonroad vehicles and engines
D Fuel combustion
n Metals Industrial processing
n On-road vehicles
70
75
'80
Year
'85 '90-'99and'02°
Emissions inventory
data are presented
for years that allow
reliable estimation of
long-term trends.
bData for 1990-1999
and 2002 are average
annual emissions
(thousand tons per
year) and are
therefore comparable
to the annual
emissions shown for the earlier years.
Data source: 1970-1985 data from National Emissions Data
System (NEDS) archives, and 1990-1999 and 2002 data from U.S.
EPA, National Emissions Inventory (NEI), 2005
Although lead emissions trends have
been generated using well-established
estimation methods, the data reflect
estimates based on empirical and
engineering models and not actual
measurement of lead emissions. These
estimates have uncertainties inherent
in the emission factors and emission
models used to represent sources for
which emissions have not been
directly measured.
The method for estimating lead
emissions for fuel combustion and
industrial sources changed in 1999 to
reduce uncertainties inherent in the
previous method (U.S. EPA, 2003).
Despite the change in methodology,
the long-term trend is still reliable.
Not all states and local agencies
provide the same data or level of
detail for a given year.
Data Sources
Summary data in this indicator were provided by
EPA's Office of Air Quality Planning and
26 Standards, based on raw lead emissions data from two sources. Raw emissions data from 1970 to 1985
27 are from EPA's National Emissions Data System (NEDS) archives, and data summaries for this time
28 frame can be found in various EPA publications (e.g., U.S. EPA, 2001). Raw emissions data for 1990-
29 1999 and 2002 are available from EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
30 (http://www.epa.gov/ttn/chief/net/2002inventory .html). This indicator aggregates the raw emissions data
31 by source category.
32 References
33 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
34
35 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
36
38 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
39 EPA/454/R-03/005. Research Triangle Park, NC.
40 U.S. EPA. 2001. National air quality and emissions trends report, 1999. EPA/454/R-01-004. Research
41 Triangle Park, NC.
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NDICATOR: Ambient Concentrations of Le
2 Lead is a naturally occurring metal found in small amounts in rock and soil. Despite steep decreases in
3 emissions since 1970 (the Lead Emissions indicator, p. 2-19), lead remains an important environmental
4 health issue because exposure to high levels has been associated with serious health effects, including
5 neurological impairments such as seizures, mental retardation, and behavioral disorders (CDC, 2005).
6 Even at low doses, lead exposure can have adverse effects to the nervous systems of fetuses and young
7 children (the Blood Lead indicator, p. 5-76) (U.S. EPA, 2006a). Lead exposure can occur by inhalation of
8 airborne particles that contain lead, drinking contaminated water, eating contaminated food items, or by
9 ingesting non-food items that contain lead, such as dust and paint chips.
10 Lead has been used industrially in the production of gasoline, ceramic products, paints, metal alloys,
11 batteries, and solder. Some chemicals containing lead were previously added to gasoline to enhance
12 vehicle performance, but that practice was phased out during the 1970s and 1980s. As a result, air
13 emissions of lead from the transportation sector decreased dramatically during that period (the Lead
14 Emissions indicator, p. 2-19). Today, the highest levels of airborne lead are usually found near industrial
15 operations that process materials containing lead, such as smelters (U.S. EPA, 2003).
16 This indicator reflects ambient lead concentrations in micrograms per cubic meter (ug/m3) from 1980 to
17 2004. Trends for this indicator are based on measurements made at the 18 monitoring stations in the
18 National Air Monitoring Stations (NAMS) and State and Local Air Monitoring Stations (SLAMS)
19 network that have consistently measured ambient air concentrations of lead over the entire period of
20 interest. Reported values are annual maximum quarterly averages. This indicator's exhibit displays the
21 lead National Ambient Air Quality Standard (NAAQS) as a point of reference, but the fact that the
22 national lead concentrations fall below the standard does not mean that all monitoring sites also are below
23 the standard.
24 What the Data Show
25 Between 1980 and 2004, average lead concentrations decreased 97 percent nationally (Exhibit 2-6, panel
26 A). This decrease, which occurred mostly during the 1980s and early 1990s, is largely attributed to
27 reduced lead content in gasoline (U.S. EPA, 2003). In addition, of the 18 sites comprising this trend (out
28 of 185 total monitoring sites that were operating in 2004), the number reporting lead concentrations above
29 the NAAQS declined to zero over the same period (Exhibit 2-6, panel B).
30 Also shown in Exhibit 2-6 (panel A) are the 90th and 10th percentiles based on the distribution of annual
31 statistics at the monitoring sites. This provides additional graphical representation of the distribution of
32 measured concentrations across the monitoring sites for a given year. Thus, the exhibit displays the
33 concentration range where 80 percent of measured values occurred for each year.
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1 Indicator Limitations
2
3
4
5
6
9
10
11
12
13
14
15
16
17
18
Because most lead monitoring sites are
located in urban areas, the nationwide
trends might not accurately reflect
conditions outside the immediate urban
monitoring areas.
To ensure that long-term trends are
based on a consistent set of monitoring
sites, selection criteria were applied to
identify the subset of lead monitoring
sites with sufficient data to assess trends
since 1980. Monitoring sites without
sufficient data are not included in the
trend analysis. Some excluded
monitoring sites reported lead
concentrations above the lead standard
over the time frame covered by this
indicator.
19 Data Sources
20 Summary data in this indicator were provided by
21 EPA's Office of Air Quality Planning and
22 Standards, based on raw lead ambient air monitorinj
23 data in EPA's Air Quality System (AQS) (U.S.
24 EPA, 2006b) (http://www.epa.gov/ttn/airs/airsaqs/').
25 National trends in this indicator are based on the
26 subset of lead monitoring stations that have
27 sufficient data to assess trends since 1980.
28 References
Exhibit 2-6. Ambient lead concentrations in
the U.S., 1980-20043
A. Ambient concentrations
NAAQS = 1.5Mg/m3
L 90% of sites have concentrations below this line
10% of sites have
concentrations below this line
o.o
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
B. Number of trend sites above NAAQS
a> c
.
'80 '82 '84 '86 '88 '90
'92 '94
Year
'96 '98 '00 '02 '04
Coverage: 18 monitoring sites nationwide (out of a total of 185 sites
measuring lead in 2004) that have sufficient data to assess lead
trends since 1980.
Data source: U.S. EPA, Air Quality System, 2005
29 CDC (Centers for Disease Control and Prevention,
30 National Center for Environmental Health). 2005. Third national report on human exposure to
31 environmental chemicals. NCEH Pub. No. 05-0570. July 2005. (Accessed September 9, 2005)
32
33 U.S. EPA. 2006a. Air quality criteria for lead. EPA/600/R-5/144aF.
34 U.S. EPA. 2006b. Data from the Air Quality System. Accessed 2006.
35
36 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
37 EPA/454/R-03/005. Research Triangle Park, NC.
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INDICATOR: Nitrogen Oxides Emissions
2 Nitrogen oxides (NOX) is the term used to describe the sum of nitric oxide (NO), nitrogen dioxide (NO2),
3 and other oxides of nitrogen. Most airborne NOX come from combustion-related emissions sources of
4 human origin, primarily fossil fuel combustion in electrical utilities, high temperature operations at other
5 industrial sources, and operation of motor vehicles. However, natural sources, like biological decay
6 processes and lightning, also contribute to airborne NOX. Fuel-burning appliances, like home heaters and
7 gas stoves, produce substantial amounts of NOX in indoor settings (U.S. EPA, 2003).
8 NOX plays a major role in several important environmental and human health issues. Short-term and long-
9 term exposures to elevated air concentrations of NO2 are associated with various acute and chronic
10 respiratory effects (U.S. EPA, 1993). NOX and volatile organic compounds (VOCs) react in the presence
11 of sunlight to form ozone, which also is associated with human health and ecological effects (the Ozone
12 Concentrations indicator, p. 2-32). NOX and other pollutants react in the air to form compounds that
13 contribute to acid deposition, which can damage forests and cause lakes and streams to acidify (the Acid
14 Deposition indicator, p. 2-56). Deposition of NOX also affects nitrogen cycles and can contribute to
15 nuisance growth of algae that can disrupt the chemical balance of nutrients in water bodies, especially in
16 coastal estuaries (the Lake and Stream Acidity indicator, p. 2-62; the Trophic State of Coastal Waters
17 indicator, p. 3-62). NOX also plays a role in several other environmental issues, including formation of
18 particulate matter (the PM Concentrations indicator, p. 2-44), decreased visibility (the Regional Haze
19 indicator, p. 2-50), and global climate change (the U.S. Greenhouse Gas Emissions indicator, p. 2-96; the
20 Greenhouse Gas Concentrations indicator, p. 2-100).
21 This indicator presents NOX emissions from traditionally inventoried anthropogenic source categories:
22 1) "Fuel combustion: selected power generators," which includes emissions from coal, gas and oil-fired
23 power plants that are required to use continuous emissions monitors (CEMs) to report emissions as part of
24 the Acid Rain Program (ARP); 2) "Fuel combustion: other sources," which includes industrial,
25 commercial, and institutional sources, as well as residential heaters and boilers not required to use CEMs;
26 3) "Other industrial processes," which include chemical production and petroleum refining; 4) "On-road
27 vehicles," which includes cars, trucks, buses, and motorcycles; 5) "Nonroad vehicles and engines," such
28 as farm and construction equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft, and
29 others. Since a substantial portion of airborne NOX comes from fossil fuel combustion in electric utilities,
30 this indicator includes the separate category for "selected power generators" in addition to the four
31 categories presented in the other emissions indicators. The indicator also includes estimates of biogenic
32 NOX emissions in 2002 which were obtained using the Biogenic Emissions Inventory System (BEIS)
3 3 Model, Version 3.12.
34 NOX emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite of
35 data from many different data sources, including industry and numerous state, tribal, and local agencies.
36 Different data sources use different data collection methods, and many of the emissions data are based on
37 estimates rather than actual measurements. For major electric generating units, most data come from
38 continuous emissions monitors that measure actual emissions. For other fuel combustion sources and
39 industrial processes, data are estimated using emission factors. Emissions from on-road and nonroad
40 sources were estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
41 NEI data have been collected since 1990 and cover all 50 states and their counties, D.C., the U.S.
42 territories of Puerto Rico and Virgin Islands, and some of the territories of federally-recognized American
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1 Indian nations. Data are presented only for 1990 and the years from 1996 to 2002; prior to 1996, only the
2 1990 data have been updated to be comparable to the more recent inventories.
3 What the Data Show
4 Only NOX emissions from anthropogenic sources are included in the NEI. However, NOX emissions from
5 biogenic sources were estimated for 2002 to provide a sense of the relative contributions of natural versus
6 anthropogenic emissions. Nationally, biogenic emissions were estimated to contribute approximately 5
7 percent to NOX emissions from all sources during 2002 (Exhibit 2-7, panel B).
8 According to the NEI data, estimated nationwide anthropogenic emissions of NOX decreased by 18
9 percent between 1990 and 2002 (from 25,160,000 to 20,746,000 tons) (Exhibit 2-7, panel A). This
10 downward trend results primarily from emissions reductions at electrical utilities and among on-road
11 mobile sources. Although total nationwide anthropogenic NOX emissions decreased during this period,
12 emissions from some sources (such as nonroad vehicles and engines) have increased since 1990.
13 Estimated anthropogenic NOX emissions in all ten EPA Regions decreased between 1990 and 2002
14 (Exhibit 2-8). The percent reductions in emissions over this time frame ranged from 3 percent (in Region
15 6) to 35 percent (in Region 1), and the largest absolute reduction (1,020,000 pounds) occurred in Region
16 5.
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
17 Indicator Limitations
Comparable NOX emissions estimates
through the NEI are available only for
1990 and 1996-2002. Data for 1991-1995
are not provided due to differences in
emission estimation methodologies from
other inventory years which could lead to
improper trend assessments.
NOX emissions from miscellaneous
sources are not included in the total
emissions.
Though NOX emissions from most electric
utilities are measured directly using
continuous monitoring devices, NOX
emissions data for most other source types
are estimates. These estimates are
generated using well-established
approaches, but still have uncertainties
inherent in the emission factors and
emission models used to represent sources
for which emissions have not been directly
measured.
The methodology for estimating emissions
is continually reviewed and is subject to
revision. Trend data prior to any revisions
Exhibit 2-7. NOX emissions in the U.S., 1990
and 1996-2002
A. Anthropogenic NOX emissions by source category3
Emissions (million tons)
J3
30
25
20
15
10
5
0
i
1
~
T
9(
A
Other industrial processes
Fuel combusti6nT"~ ir~~-\
selected power generators \"
Fuel combustion: other sources \
On-road vehicles
Nonroad vehicles and engines
'96 '97 '98 '99 '00 '01 '0
Year
"Data are presented for 1990 and
1996-2002, as datasets from
these inventory years are fully
up-to-date. Data are available for
inventory years 1991 -1995, but
these data have not been updated
to allow comparison with data
from 1990 and 1996-2002.
blhis category includes emissions
from only those power plants
required to use continuous
emissions monitors under the
Acid Rain Program.
Data source: U.S. EPA, National
Emissions Inventory (NEI), 2005
B. Relative amounts of NOx
emissions from anthropogenic
and biogenic sources, 2002
.Biogenic
k 5%
Anthropogenic
95%
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Exhibit 2-8. NOX emissions in the U.S. by EPA
Region, 1990 and 1996-2002"
w- 5
a
I 4
f s
o
'GO
_w 2
LLJ
1
0
-R1
—R2
-R3
-R4
-R5
—R6
—R7
-R8
-R9
—R10
'96 '97 '98 '99 '00 '01 '02
Year
EPA Regions
"Data are presented for 1990
and 1996-2002, as datasets
from these inventory years are
fully up-to-date. Data are
available for inventory years
1991-1995, but these data have
not been updated to allow
comparison with data from
1990 and 1996-2002.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
must be considered in the context of
those changes.
• Not all states and local agencies
provide the same data or level of
detail for a given year.
Data Sources
Summary data in this indicator were provided by
EPA's Office of Air Quality Planning and
Standards, based on raw NOX emissions data in
EPA's National Emissions Inventory (NEI) (U.S.
EPA, 2006)
(http: //www. epa. gov/ttn/chief/net/2002inventory .h
tml). This indicator aggregates the raw NEI data
by source type (anthropogenic or biogenic),
source category, and EPA Region.
References
U.S. EPA. 2006. Data from the National
Emissions Inventory. Accessed 2006.
21 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
22
24 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
25 EPA/454/R-03/005. Research Triangle Park, NC.
26 U.S. EPA. 1993. Air quality criteria for oxides of nitrogen. EP A/600/8-9 !/049aF-cF. Research Triangle
27 Park, NC.
28
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INDICATOR: Ambient Concentrations of Nitrogen Dioxide
2 Nitrogen dioxide (NO2) is a reddish-brown, highly reactive gas that is formed in the ambient air through
3 the oxidation of nitric oxide (NO). Nitrogen dioxide is one in a group of highly reactive gases generically
4 referred to as "nitrogen oxides" (NOX), all of which contain nitrogen and oxygen in varying amounts.
5 Nitrogen oxides play a major role in the formation of ozone in the atmosphere through a complex series
6 of reactions with volatile organic compounds (VOCs). Nitrogen dioxide is the most widespread and
7 commonly found nitrogen oxide (U.S. EPA, 2003).
8 Short-term exposures (e.g., less than 3 hours) to low-levels of NO2 may lead to changes in airway
9 responsiveness and lung function in individuals with preexisting respiratory illnesses. These exposures
10 may also increase respiratory illnesses in children. Long-term exposures to NO2 may lead to increased
11 susceptibility to respiratory infection and may cause irreversible alterations in lung structure (U.S. EPA,
12 1995).
13 Atmospheric transformation of NOX can lead to the formation of ozone and nitrogen-bearing particles
14 (e.g., nitrates and nitric acid). Deposition of nitrogen can lead to fertilization, eutrophication, or
15 acidification of terrestrial, wetland, and aquatic (e.g., fresh water bodies, estuaries, and coastal water)
16 systems. These effects can alter competition among existing species, leading to changes in species
17 abundance and distribution within communities. For example, eutrophic conditions in aquatic systems can
18 produce explosive growth of algae leading to hypoxia or an increase in levels of toxins harmful to fish
19 and other aquatic life (U.S. EPA, 1993).
20 This indicator presents ambient NO2 concentrations in parts per million (ppm) from 1980 to 2004, based
21 on the annual arithmetic average. The indicator displays trends averaged over 91 sites that have consistent
22 data for the period of record in the National Air Monitoring Stations (NAMS), State and Local Air
23 Monitoring Stations (SLAMS) network, and other special purpose monitors. It also shows trends in the
24 annual average NO2 measurements in each EPA Region. This indicator's exhibits display the NO2
25 National Ambient Air Quality Standard (NAAQS) as a point of reference, but the fact that the national or
26 any regional mean values fall below the standard does not mean that all monitoring sites nationally or in
27 the EPA Region also are below the standard. This indicator displays trends in the number of the 91 sites
28 nationwide at which NO2 concentrations exceeded the annual average standard over the period of record,
29 but this statistic is not displayed for each EPA Region.
30 What the Data Show
31
32
33
34
35
36
37
38
39
40
41
The national annual mean NO2 concentration in 2004 was 37 percent lower than that recorded in 1980
(Exhibit 2-9, panel A). Also shown on this graph are the 90th and 10th percentiles of NO2 concentrations
based on the distribution of annual statistics at the monitoring sites. This provides additional graphical
representation of the distribution of measured concentrations across the monitoring sites for a given year.
Thus, for each year, the graphic displays the concentration range where 80 percent of measured values
occurred. The highest annual mean NO2 concentrations are typically found in urban areas. In addition, of
the 91 sites comprising this trend (out of 373 total monitoring sites that were operating in 2004), the
number reporting NO2 concentrations above the NO2 standard declined from seven sites in 1981 to zero
sites since 1992 (Exhibit 2-9, panel B).
NO2 levels in all ten EPA Regions have steadily decreased since 1980, with percent reductions over this
time ranging from 25 percent in Region 8 to 44 percent in Region 9 (Exhibit 2-10).
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Exhibit 2-9. Ambient NOa concentrations in the
U.S., 1980-2004"
Exhibit 2-10. Ambient NO2 concentrations in the
contiguous U.S. by EPA Region, 1980-2004ab
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
'Coverage: 91 monitoring sites nationwide (out of a total of 373
sites measuring N02 in 2004) that have sufficient data to assess
N02 trends since 1980.
Data source: U.S. EPA, Air Quality System, 2005
The decrease in NO2 concentrations in this indicator
is consistent with decreasing NOX emissions
observed over the past decade (the Nitrogen Oxides
Emissions indicator, p. 2-23).
A. Ambient concentrations
NAAQS = 0.053 ppm
90% of sites have concentrations below this line
10% of sites have
concentrations below this line
'90 '92 '94 '96 '98 '00 '02 '04
Year
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
B. Number of trend sites above NAAQS
Coverage: 91 monitoring
sites in the EPA Regions
(out of a total of 373 sites
measuring NOa in 2004)
that have sufficient data
to assess N02 trends
since 1980.
Because N02 in Region 10
has been at such low
concentrations, none of this Region's monitoring sites have a
complete record dating back to 1980. Thus, no trend line for Region
10 is shown.
Data source: U.S. EPA, Air Quality System, 2005
Indicator Limitations
9
10
11
12
13
14
15
16
17
Because ambient monitoring for NO2 occurs almost exclusively in high traffic urban areas,
the average concentrations presented in this indicator likely are not representative of NO2
levels in rural areas. Also, in rural areas, air mass aging could foster greater relative levels of
peroxyacetyl nitrate (PAN) and nitric acid which can cause a positive interference in NO2
measurements.
The measurement of NO2 is based on the conversion of NO2 to NO and the subsequent
detection of NO using the chemiluminescence technique. Because there are other nitrogen-
containing compounds, such as PAN and nitric acid that can be converted to NO, the
chemiluminescence technique may overestimate NO2 due to these interferences.
Measurement devices with ultraviolet photolytic converters are less prone to interferences
than devices with heated surfaces (or catalysts) upstream of the chemiluminescence detector.
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1 • Because of the relatively small number of trend sites in some EPA Regions, the regional
2 trends are subject to greater uncertainty than the national trends. Some EPA Regions with low
3 average concentrations may include areas with high local concentrations, and vice versa.
4 • To ensure that long-term trends are based on a consistent set of monitoring sites, selection
5 criteria were applied to identify the subset of NO2 monitoring sites with sufficient data to
6 assess trends since 1980. Monitoring sites without sufficient data are not included in the trend
7 analysis. Some excluded monitoring sites reported NO2 concentrations above the NO2
8 standard over the time frame covered by this indicator.
9 Data Sources
10 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
11 based on raw NO2 ambient air monitoring data in EPA's Air Quality System (AQS) (U.S. EPA, 2006)
12 (http://www.epa.gov/ttn/airs/airsaqs/). National and regional trends in this indicator are based on the
13 subset of NO2 monitoring stations that have sufficient data to assess trends since 1980.
14 References
15 U.S. EPA. 2006. Data from the Air Quality System. Accessed 2006.
16
17 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
18 EPA/454/R-03/005. Research Triangle Park, NC.
19 U.S. EPA. 1995. Review of the national ambient air quality standards for nitrogen oxides: assessment of
20 scientific and technical information. EPA/452/R-95/005. Research Triangle Park, NC.
21 U.S. EPA. 1993. Air quality criteria for oxides of nitrogen. EP A/600/8-9 !/049aF-cF. Research Triangle
22 Park, NC.
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INDICATOR: Volatile Organic Compounds Emissions
2 Volatile organic compounds (VOCs) are a large group of organic chemicals that include any compound of
3 carbon (excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and
4 ammonium carbonate) and that participate in atmospheric photochemical reactions. VOCs are of interest
5 because they contribute to ozone formation (U.S. EPA, 2003a) and because many individual VOCs are
6 known to be harmful to human health (the Benzene Concentrations indicator, p. 2-74; the Air Toxics
7 Emissions indicator, p. 2-70). Health effects vary by pollutant. Emissions of all VOCs combined are also
8 considered an important environmental and human health issue because ozone, another air pollutant (the
9 Ozone Concentrations indicator, p. 2-32), is formed from chemical reactions involving airborne VOCs,
10 airborne nitrogen oxides, and sunlight. VOCs are emitted from a variety of sources, including motor
11 vehicles, chemical manufacturing facilities, refineries, factories, consumer and commercial products, and
12 natural (biogenic) sources (mainly trees) (U.S. EPA, 2003b).
13 This indicator presents VOC emissions from traditionally inventoried anthropogenic source categories:
14 1) "Fuel combustion," which includes emissions from coal, gas and oil-fired power plants, industrial,
15 commercial, and institutional sources, as well as residential heaters and boilers; 2) "Industrial and other
16 processes," which includes chemical production, petroleum refining, and metals production; 3) "On-road
17 vehicles," which includes cars, trucks, buses, and motorcycles; and 4) "Nonroad vehicles and engines,"
18 such as farm and construction equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft,
19 and others. The indicator also includes estimates of biogenic VOC emissions in 2002 which were
20 obtained using the Biogenic Emissions Inventory System (BEIS) Model, Version 3.12.
21 VOC emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite of
22 data from many different data sources, including industry and numerous state, tribal, and local agencies.
23 Different data sources use different data collection methods, and many of the emissions data are based on
24 estimates rather than actual measurements. For most fuel combustion sources and industrial sources,
25 emissions are estimated using emission factors. Emissions from on-road and nonroad sources were
26 estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
27 NEI data have been collected since 1990 and cover all 50 states and their counties, B.C., the U.S.
28 territories of Puerto Rico and Virgin Islands, and some of the territories of federally-recognized American
29 Indian nations. Data are presented only for 1990 and the years from 1996 to 2002; prior to 1996, only the
30 1990 data have been updated to be comparable to the more recent inventories.
31 What the Data Show
32 Only VOC emissions from anthropogenic sources are included in the NEI. However, VOC emissions
33 from biogenic sources were estimated for 2002 to provide a sense of the relative contributions of natural
34 versus anthropogenic emissions. Nationally, biogenic emissions were estimated to contribute
35 approximately 72 percent to VOC emissions from all sources during 2002 (Exhibit 2-11, panel B). Thus,
36 VOC emissions from biogenic sources are larger than the VOC emissions from all anthropogenic sources
37 combined.
38 According to NEI data, national total estimated VOC emissions from anthropogenic sources, excluding
39 wildfires and prescribed burns, decreased by 32 percent between 1990 and 2002 (from 23,048,000 to
40 15,662,000 tons) (Exhibit 2-11, panel A). The overwhelming majority of anthropogenic emissions
41 reductions were observed among industrial processes and on-road mobile sources. Combined, these two
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1 source categories accounted for 84 percent of the total nationwide estimated anthropogenic VOC
2 emissions in 1990 (excluding wildfires and prescribed burns), but accounted for only 76 percent of the
3 nationwide anthropogenic emissions in 2002.
4 Trends in estimated anthropogenic VOC emissions among the ten EPA Regions were consistent with the
5 overall decline seen nationally from 1990 to 2002 (Exhibit 2-12). VOC emissions decreased in every EPA
6 Region, with the percent decrease ranging from 12 percent (Region 10) to 44 percent (Region 9).
Exhibit 2-11. VOC emissions in the U.S., 1990
and 1996-2002
Exhibit 2-12. VOC emissions in the U.S. by
EPA Region, 1990 and 1996-2002"
A. Anthropogenic VOC emissions by source category3
Industrial and other processes
Nonroad vehicles and engines
96 '97 '98 '99 '00 '01 '02
Year
B. Relative amounts of VOC
emissions from anthropogenic
and biogenic sources, 2002
Data are presented for 1990
and 1996-2002, as datasets
from these inventory years
are fully up-to-date. Data are
available for inventory years
1991-1995, but these data
have not been updated to
allow comparison with data
from 1990 and 1996-2002.
aData are presented lor 1990
and 1996-2002, as datasets
from these inventory years are
fully up-to-date. Data are
available for inventory years
1991-1995, but these data have
not been updated to allow
comparison with data from
1990 and 1996-2002.
Anthropogenic
28%
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
Data source: U.S. EPA,
National Emissions
Inventory (NEI), 2005
7 Indicator Limitations
9
10
11
12
13
14
15
16
Comparable VOC emissions estimates through the NEI are available only for 1990 and 1996-
2002. Data for 1991-1995 are not provided due to differences in emission estimation
methodologies from other inventory years which could lead to improper trend assessments.
VOC emissions from "miscellaneous sources" are not included in the total emissions. Details
on emissions from miscellaneous sources can be found at
http: //www .epa. gov/ttn/chief/eiinformation .html.
VOC emissions data are largely based on estimates that employ emission factors generated
from empirical and engineering studies, rather than on actual measurements of VOC
emissions. Although these estimates are generated using well-established approaches, the
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1 estimates have uncertainties inherent in the emission factors and emission models used to
2 represent sources for which emissions have not been directly measured.
3 • The methodology for estimating emissions is continually reviewed and is subject to revision.
4 Trend data prior to any revisions must be considered in the context of those changes.
5 • Not all states and local agencies provide the same data or level of detail for a given year.
6 Data Sources
7 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
8 based on raw VOC emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
9 (http://www.epa.gov/ttn/chief/net/2002inventory.html). This indicator aggregates the raw NEI data by
10 source type (anthropogenic or biogenic), source category, and EPA Region.
11 References
12 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
13
14 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
15
17 U.S. EPA. 2003a. Requirements for preparation, adoption, and submittal of implementation plans:
18 definitions. Code of Federal Regulations 40CFR51.100(s).
19 U.S. EPA. 2003b. National air quality and emissions trends report—2003 special studies edition.
20 EPA/454/R-03/005. Research Triangle Park, NC.
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INDICATOR: Ambient Concentrations of Ozone
2 Ozone is a gas found in different parts of the atmosphere. Ozone in the upper atmosphere, or stratosphere,
3 helps protect the Earth from the sun's harmful rays. (The Ozone Levels over North America indicator, on
4 page 2-79, describes trends in stratospheric ozone levels over the U.S.) In the lowest level of the
5 atmosphere, or troposphere, ozone is harmful to both human health and the environment. For this reason,
6 ozone is often described as being "good up high and bad nearby" (U.S. EPA, 2003a). Although some
7 industrial sources release ozone directly into the environment, most ground-level ozone forms in the air
8 from chemical reactions involving nitrogen oxides (NOX), volatile organic compounds (VOCs), and
9 sunlight. Ozone levels are typically highest during the afternoon hours of the summer months when the
10 influence of direct sunlight is the greatest. These highest levels occur during what is known as the "ozone
11 season" which typically occurs from May 1 to September 30, but the time frame of the ozone season
12 varies by state (U.S. EPA, 2003b).
13 Variations in weather conditions play an important role in determining ozone levels. Daily temperatures,
14 relative humidity, and wind speed can affect ozone levels. In general, warm dry weather is more
15 conducive to ozone formation than cool wet weather. Wind can affect both the location and concentration
16 of ozone pollution. NOX and VOC emissions can travel hundreds of miles on air currents, forming ozone
17 far from the original emission sources. Ozone also can travel long distances, affecting areas far
18 downwind. High winds tend to disperse pollutants and can dilute ozone concentrations. However,
19 stagnant conditions or light winds allow pollution levels to build up and become more concentrated.
20 Inhalation exposure to ozone has been linked to numerous respiratory health effects, including acute
21 reversible decrements in lung function, airway inflammation, cough, and pain when taking a deep a
22 breath. Ozone exposure can aggravate lung diseases such as asthma, leading to increased medication use
23 and increased hospital admission and visits to emergency rooms. In addition, evidence is highly
24 suggestive that ozone directly or indirectly contributes to non-accidental and cardiopulmonary-related
25 mortality, but the underlying mechanisms by which such effects occur have not been fully established
26 (U.S. EPA, 2006a). Although people with lung disease are most susceptible to the effects of ozone, even
27 healthy people who are active outdoors can suffer from ozone-related health effects. Further, evidence
28 suggests that older adults (greater than 65 years old) appear to be at excess risk of ozone-related mortality
29 or hospitalization (U.S. EPA, 2006a). Elevated concentrations of ozone can also affect vegetation and
30 ecosystems, as the Ozone Injury to Forest Plants indicator (p. 2-37) describes further (U.S. EPA, 1996).
31 This indicator presents ambient ground-level ozone concentrations in parts per million (ppm) from 1978
32 to 2004. Data are shown for 1-hour and 8-hour averaging times, based on continuous ozone monitoring
33 data and consistent with this pollutant's National Ambient Air Quality Standards (NAAQS). The 1-hour
34 standard is useful in indicating potential effects during short-term "spikes" in concentrations. The longer
35 8-hour standard is indicative of exposures occurring over a more sustained period of time (e.g., an
3 6 outdoor worker's exposure over the course of a work day). Trends for this indicator represent 213 sites
37 that have data for the period of record in the National Air Monitoring Stations (NAMS), the State and
38 Local Air Monitoring Stations (SLAMS) network, and other special purpose monitors. The indicator also
39 displays trends in ozone measurements in each EPA Region. This indicator's exhibits display the
40 corresponding NAAQS as points of reference, but the fact that the national or regional concentrations fall
41 below the standards does not mean that all monitoring sites nationally or in any EPA Region also are
42 below the standard. The indicator displays trends in the number of the 213 sites nationwide at which
43 ozone concentrations exceeded standards, but these statistics are not displayed for each EPA Region.
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1 Trends in ozone concentrations can be difficult to discern because of the year-to-year variations in the
2 concentrations. By presenting data on a rolling 3-year time period, this indicator smooths out the "peaks"
3 and "valleys" in the trend, making it easier to read without changing the overall trend statistic. Three
4 years is consistent with the 3-year period used to assess compliance with the ozone standards. For the 1-
5 hour trends in this report, the second highest daily maximum over a 3-year period is used to be consistent
6 with the 1-hour ozone standard. For the 8-hour trends in this report, a 3-year average of the fourth highest
7 daily maximum in each year is used to be consistent with the 8-hour ozone standard. The 3-year statistic
8 is assigned to the last year in each 3-year period. For example, 1980 is based on 1978-1980, and 2004 is
9 based on 2002-2004. Thus, when endpoint comparisons are used in this report to describe long-term
10 changes (i.e., 1978-2004), they are based on the first 3-year period and the last 3-year period.
11 What the Data Show
12 Between the 1978-1980 and 2002-2004 averaging periods, nationwide 1-hour average ambient ozone
13 levels decreased by 26 percent (Exhibit 2-13, panel A). In addition, among the 213 monitoring sites used
14 to estimate the 1978-2004 trend, the number measuring ozone concentrations above the 1-hour NAAQS
15 (National Ambient Air Quality Standard) declined 77 percent over the same period (Exhibit 2-13, panel
16 B).
17 All ten EPA Regions also experienced some decline in 1-hour average ozone levels dating back to the
18 1978-1980 averaging period (Exhibit 2-14). The greatest percent reductions in 1-hour ozone
19 concentrations were observed in the two EPA Regions (Regions 1 and 9) that had the highest ozone levels
20 in 1980, although the South Coast area in EPA Region 9 continues to have some of the highest ozone
21 levels in the nation. EPA Region 10 showed the lowest ambient ozone concentrations over most of the
22 period of record.
23 Between the 1978-1980 and 2002-2004 averaging periods, nationwide 8-hour average ambient ozone
24 concentrations decreased by 21 percent (Exhibit 2-15, panel A). Although the 8-hour ozone levels in 2004
25 ranked among the lowest on record and the number of trend sites measuring ozone concentrations above
26 the 8-hour NAAQS decreased by 84 percent over the time frame covered in this indicator (Exhibit 2-15,
27 panel B), ambient air monitoring data collected in 2005 and reported to EPA's Air Quality System
28 indicates that approximately 118 million people live in 47 metropolitan areas where 8-hour average ozone
29 concentrations do not meet EPA's health-based air quality standards .Among the ten EPA Regions, the
30 most substantial declines in 8-hour levels were again observed in EPA Regions that originally had the
31 highest ozone concentrations (EPA Regions 1 and 9) (Exhibit 2-16). Most other Regions showed less
32 pronounced declines (e.g., EPA Regions 6 to 10). Region 10 again consistently showed the lowest
33 Regional ozone levels.
34 Also shown in Exhibits 2-13 and 2-15 (panel A, in both cases) are the 90th and 10th percentiles based on
35 the distribution of annual statistics at the monitoring sites. This provides additional graphical
36 representation of the variability of measured concentrations across the monitoring sites for a given year.
37 Thus, the graphic displays the concentration range where 80 percent of measured values occurred for that
38 year.
39 In summary, despite reductions in ambient concentrations of ozone over the past quarter century and
40 decreases in the emissions of ozone precursors since 1990 (the Nitrogen Oxides Emissions indicator, p. 2-
41 23; the VOC Emissions indicator, p. 2-29), ozone remains one of the most persistent and ubiquitous air
42 pollution issues in the U.S.
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Exhibit 2-13. Ambient 1-hour ozone
concentrations in the U.S., 1978-2004"
A. Ambient concentrations (1 978-2DD4)
90% of sites have
concentrations below this line
NAAQS = 0.12 ppm
Exhibit 2-14. Ambient 1-hour ozone
concentrations in the contiguous U.S. by EPA
Region, 1978-2004"
10% of sites have
concentrations below this line
NAAQS = 0.12 ppm
78-'80 '82-'84 '8B-'88 '90-'92 '94-'96
Averaging period
B. Number of trend sites above NAAQS (1980-2004)
'86-'88 '94-'96
Averaging period
"Coverage: 213 monitoring
sites in the EPA Regions (out of
a total of 1 ,203 sites measuring
ozone in 2004) that have
sufficient data to assess ozone
trends si nee 1978.
Data source: U.S. EPA, Air
Quality System, 2005
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
"Coverage: 21 3 monitoring sites nationwide (out of a total of 1 ,203
sites measuring ozone in 2004) that have sufficient data to assess
ozone trends since 1978.
Data source: U.S. EPA, Air Quality System, 2005
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Exhibit 2-15. Ambient 8-hour ozone
concentrations in the U.S., 1978-2004
A. Ambient concentrations (1978-2004)
90% of sites have concentrations below this line
NAAQS = 0.08 ppm
10% of sites nave concentrations below this line
78-'80 '82-84 '86-88 '90-92 '94-96 '98-00 '02-'04
Averaging period
B. Number of trend sites above NAAQS (1980-2004)
'80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
Coverage: 213 monitoring sites nationwide (out of a total of 1,203
sites measuring ozone in 2004) that have sufficient data to assess
ozone trends since 1978.
Data source: U.S. EPA, Air Quality System, 2005
12
13
14
15
16
17
18
19
Exhibit 2-16. Ambient 8-hour ozone
concentrations in the contiguous U.S. by EPA
Region, 1978-2004"
v NAAQS = 0.08 ppm
-R1
-R2
-R3
-R4
-R5
R6
-R7
R8
-R9
-R10
-Nat'l
78-'80
'86-'88 '94-'96
Averaging period
'02-'04
Coverage: 213 monitoring
sites in the EPA Regions (out of
EPA Regions
a total of 1,203 sites measuring
ozone in 2004) that have
sufficient data to assess ozone
trends since 1978.
Data source: U.S. EPA, Air
Quality System, 2005
Indicator Limitations
• Short-term trends in ozone
concentrations are often highly
dependent on meteorological conditions.
This complicates efforts to interpret data
for any given year. Air quality trends
over the longer term are far less likely to
be influenced by unusual meteorological
conditions.
Because most of the monitoring sites are located in urban areas, the trends might not
accurately reflect conditions outside the immediate urban monitoring areas.
Because of the relatively small number of trend sites in some EPA Regions, the regional
trends are subject to greater uncertainty than the national trends. Some EPA Regions with low
average concentrations may include areas with high local concentrations, and vice versa.
To ensure that long-term trends are based on a consistent set of monitoring sites, selection
criteria were applied to identify the subset of ozone monitoring sites with sufficient data to
assess trends since 1978. Monitoring sites without sufficient data are not included in the trend
analysis. Some excluded monitoring sites reported ozone concentrations above the ozone
standard over the time frame covered by this indicator.
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1 Data Sources
2 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
3 based on raw ozone ambient air monitoring data in EPA's Air Quality System (AQS) (U.S. EPA, 2006b)
4 (http://www.epa.gov/ttn/airs/airsaqs/). National and regional trends in this indicator are based on the
5 subset of ozone monitoring stations that have sufficient data to assess trends since 1978.
6 References
7 U.S. EPA. 2006a. Air quality criteria for ozone and related photochemical oxidants. EPA/600/R-
8 05/004aF-cF. Research Triangle Park, NC.
9 U.S. EPA. 2006b. Data from the Air Quality System. Accessed 2006.
10
11 U.S. EPA. 2003a. Ozone: good up high, bad nearby. EPA/45 l/K-03/001. Washington, DC.
12 U.S. EPA. 2003b. Latest findings on national air quality—2002 status and trends. EPA/454/K-03/001.
13 Research Triangle Park, NC.
14 U.S. EPA. 1996. Air quality criteria for ozone and related photochemical oxidants. EPA/600/P-93/004F-
15 cF. Research Triangle Park, NC.
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NDICATOR: Ozone Injury to Forest Plan
2 Air pollution can have noteworthy cumulative impacts on forested ecosystems by affecting regeneration,
3 productivity, and species composition (U.S. EPA, 1996). In the U.S., ozone in the lower atmosphere is
4 one of the pollutants of primary concern. Ozone injury to forest plants can be diagnosed by examination
5 of plant leaves. Foliar injury is usually the first visible sign of injury to plants from ozone exposure and
6 indicates impaired physiological processes in the leaves (Grulke, 2003).
7 This indicator is based on data from the U.S. Department of Agriculture Forest Service Forest Health
8 Monitoring (FHM) Program (USDA, 2004). The FHM Program, now known as Phase 3 of the Forest
9 Inventory Analysis, examines ozone injury to ozone-sensitive plant species at ground monitoring sites in
10 forest land across the country. For this indicator, forest land does not include woodlots and urban trees.
11 Sites are selected using a systematic sampling grid, based on a global sampling design (White et al., 1992;
12 Smith et al., 2003). At each site that has at least 30 individual plants of at least three ozone-sensitive
13 species and enough open space to ensure that sensitive plants are not protected from exposure by the
14 forest canopy, FHM looks for damage on the foliage of ozone-sensitive forest plant species. Because
15 ozone injury is cumulative over the course of the growing season, examinations are conducted in July and
16 August, when ozone injury is typically highest.
17 Monitoring of ozone injury to plants in the FHM program has expanded over the last 10 years from
18 monitoring sites in ten states in 1994 to nearly 1,000 monitoring sites in 41 states in 2002. The data
19 underlying this indicator are based on averages of all observations collected in 2002, the latest year for
20 which data are publicly available, and are broken down by EPA Region. The ozone damage to forest
21 plants is classified using a subjective five-category biosite index based on expert opinion, but designed to
22 be equivalent from site to site. Ranges of biosite values translate to no injury, low or moderate foliar
23 injury (visible foliar injury to highly sensitive or moderately sensitive plants, respectively), and high or
24 severe foliar injury, which would be expected to result in tree-level or ecosystem-level responses,
25 respectively (Coulston et al., 2004; U.S. EPA, 1996).
26 What the Data Show
27 There is considerable regional variation in ozone injury to sensitive plants (Exhibit 2-17). The highest
28 percentages of observed high and severe foliar injury, which are most likely to be associated with tree or
29 ecosystem-level responses, are primarily found in the Mid-Atlantic and Southeast Regions. In EPA
30 Region 3, 12 percent of ozone-sensitive plants showed signs of high or severe foliar damage, and in
31 Regions 2 and 4, the values were 10 percent and 7 percent, respectively. High and severe ozone injury
32 ranged from 2 percent to 4 percent in EPA Regions 1, 7, and 9, and no high or severe foliar damage was
33 observed in EPA Regions 5, 6, 8, and 10. The percentage of sites showing no damage was greater than 50
34 percent in every EPA Region, and no ozone-related foliar damage was observed at any of the 129 biosites
35 in EPA Regions 8 and 10.
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1 Indicator Limitations
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
Field and laboratory studies were
reviewed to identify the forest plant
species in each region that are highly
sensitive to ozone air pollution. Other
forest plant species, or even genetic
variants of the same species, may not
be harmed at ozone levels that cause
effects on the selected ozone-sensitive
species.
Because species distributions vary
regionally, different ozone-sensitive
plant species were examined in
different parts of the country. These
target species could vary with respect
to ozone sensitivity, which might
account for some of the apparent
differences in ozone injury among
EPA Regions.
Ozone damage to foliage is
considerably reduced under conditions
of low soil moisture, but most of the
variability in the index (70 percent)
was explained by ozone concentration
(Smith et al., 2003).
Ozone may have other adverse
impacts on plants (e.g., reduced
productivity) that do not show signs of
visible foliar injury (U.S. EPA, 1996).
Though the FHM has extensive spatial
coverage based on a robust sample
design, not all forested areas in the
U.S. are monitored for ozone injury.
Even though the biosite data have
been collected over a seven year
period, most biosites were not
monitored over the entire period, so
these data cannot provide more than a
baseline for future trends.
Exhibit 2-17. Ozone injury to forest plants in
the U.S. by EPA Region, 2002a
Degree of injury:
None
Low
Moderate
High
Severe
68.5
61.9
55.9
16.7
11.1 -
21.4
7.1
7.1
18.0
14.4
7.2
75.3
10.1
7-°r
Percent of monitoring sites in each category:
Region 1
(54 sites)
Region 2
(42 sites)
Region 3
(111 sites)
Region 4
(227 sites)
Region 5
(180 sites)
Region 6
(59 sites)
Region 7
(63 sites)
Region 8
(72 sites)
Region 9
(80 sites)
Region 10
(57 sites)
75.6
18.3
6.1
94.9
85.7
9.5 |
-5.1
100.0
76.3
12.5
8.8
100.0
"Coverage: 945 monitoring sites,
located in 41 states.
Data source: USDA Forest Service,
Forest Health Monitoring (FHM)
Program database
EPA Regions
Q
0
^W
40 Data Sources
41 Data were provided by the USDA Forest Service's Ozone Biomonitoring Program, which maintains a
42 database of plant injury statistics by state (USDA Forest Service, 2006)
43 (http://www.fiaozone.net/tabular.html). This indicator aggregates the state data by EPA Region.
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1 References
2 Coulston, J.W., K.H. Riitters, and G.C. Smith. 2004. A preliminary assessment of the Montreal process
3 indicators of air pollution for the United States. Environ. Monit. Assess. 95:57-74.
4 Grulke, N.E. 2003. The physiological basis of ozone injury assessment attributes in Sierran conifers. In:
5 Bytnerowicz, A., M.J. Arbaugh, and R. Alonso, eds. Ozone air pollution in the Sierra Nevada:
6 distribution and effects on forests. New York, NY: Elsevier Science, Ltd. pp. 55-81.
7 Smith, G., J. Coulston, E. Jepsen, and T. Prichard. 2003. A national ozone biomonitoring program—
8 results from field surveys of ozone sensitive plants in Northeastern forests (1994-2000). Environ. Monit.
9 Assess. 87:271-291.
10 USDA Forest Service. 2006. Ozone bioindicator data. Accessed 2006.
11
12 USDA Forest Service. 2004. Data report: a supplement to the national report on sustainable forests—
13 2003. Washington, DC.
14 U.S. EPA. 1996. Air quality criteria for ozone and related photochemical oxidants. EPA/600/AP-
15 93/004aF-cF (NTIS PB96-185582, PB96-185590, PB96-185608). Research Triangle Park, NC.
16
17 White, D., A.J. Kimerling, and W.S. Overton. 1992. Cartographic and geometric component of a global
18 sampling design for environmental monitoring. Cartogr. Geograph. Info. Sys. 19:5-22.
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INDICATOR: Particulate Matter Emissions
2 Particulate matter (PM) is the general term used to describe solid particles and liquid droplets found in the
3 air. The composition and size of these airborne particles and droplets vary. Some particles are large
4 enough to be seen as dust or dirt, while others are so small they can only be seen using a powerful
5 microscope. Two size ranges, known as PMi0 and PM2 5, are widely monitored, both at major emissions
6 sources and in ambient air. PMi0 includes particles that have aerodynamic diameters less than or equal to
7 10 microns (um), approximately equal to one-seventh the diameter of human hair. PM2 5 is the subset of
8 PMio particles that have aerodynamic diameters less than or equal to 2.5 um.
9 Particles within the two size ranges behave differently in the atmosphere. PM2 5, or fine particles, can
10 remain airborne for long periods and travel hundreds of miles. Coarse particles, or the subset of PMi0 that
11 is larger than 2.5 um, do not remain airborne as long and their spatial impact is typically limited because
12 they tend to deposit on the ground downwind of emissions sources. Larger coarse particles are not readily
13 transported across urban or broader areas because they are generally too large to follow air streams and
14 they tend to be removed easily on contact with surfaces. In short, as the particle size increases, the amount
15 of time the particles remain airborne decreases. The PM Concentrations indicator (p. 2-44) describes the
16 various ways PM can harm human health and the environment (U.S. EPA, 2004).
17 PM can be emitted directly or formed in the atmosphere. "Primary" particles refer to those released
18 directly to the atmosphere. These include dust from roads and soot from combustion sources. In general,
19 coarse PM is composed largely of primary particles. "Secondary" particles, on the other hand, are formed
20 in the atmosphere from chemical reactions involving primary gaseous emissions. Thus, these particles can
21 form at locations distant from the sources that release the precursor gases. Examples include sulfates
22 formed from sulfur dioxide emissions from power plants and industrial facilities and nitrates formed from
23 nitrogen oxides released from power plants, mobile sources, and other combustion sources. Unlike coarse
24 PM, a much greater portion of fine PM (PM2 5) contains secondary particles (U.S. EPA, 2004).
25 This indicator presents trends in annual average primary PM emissions data tracked by the National
26 Emissions Inventory (NEI). The NEI tracks emission rate data, both measured and estimated, for primary
27 particles only. Because secondary particles are not released directly from stacks, the NEI instead tracks
28 the precursors that contribute to formation of secondary particles. These precursors include nitrogen
29 oxides, sulfur dioxide, ammonia, and other gases (e.g., particle-producing organic gases), some of which
30 are addressed in separate indicators (the Nitrogen Oxides Emissions indicator, p. 2-23; the Sulfur Dioxide
31 Emissions indicator, p. 2-53). Particles formed through secondary processes are not included in this
32 indicator.
33 Primary emissions of particulate matter can exist as solid or liquid matter (the "filterable" portion) or as
34 gases (the "condensable" portion). Data for the condensable portion exist only for the years 1999 to 2002.
35 To allow for a valid comparison of emission trends from 1990 to 2002, only data for the filterable portion
36 of PMio and PM2 5 are included in the trend graphs. Condensables are, however, included in the
37 anthropogenic sources displayed in the inset pie charts in Exhibits 2-18 and 2-20.
38 NEI data are presented for the traditionally inventoried anthropogenic source categories including:
39 1) "Fuel combustion," which includes emissions from coal, gas, and oil-fired power plants, industrial,
40 commercial, and institutional sources, as well as residential heaters and boilers; 2) "Industrial and other
41 processes," which includes chemical production, petroleum refining, and metals production; 3) "On-road
42 vehicles" which includes cars, trucks, buses, and motorcycles; and 4) "Nonroad vehicles and engines,"
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1 such as farm and construction equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft,
2 and others. This indicator includes a comparison of these anthropogenic sources with emissions from
3 miscellaneous and natural sources, such as agriculture and forestry, wildfires and managed burning, and
4 fugitive dust from paved and unpaved roads. The indicator also includes estimates of miscellaneous and
5 natural sources in 2002 which were obtained using the Biogenic Emissions Inventory System (BEIS)
6 Model, Version 3.12.
7 The NEI is a composite of data from many different data sources, including industry and numerous state,
8 tribal, and local agencies. Different data sources use different data collection methods, and many of the
9 emissions data are based on estimates rather than actual measurements. For most fuel combustion sources
10 and industrial sources, emissions are estimated using emission factors. Emissions from on-road and
11 nonroad sources were estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
12 NEI data have been collected since 1990 and cover all 50 states and their counties, B.C., the U.S.
13 territories of Puerto Rico and Virgin Islands, and some of the territories of federally-recognized American
14 Indian nations. Data are presented for 1990 and the years from 1996 to 2002; prior to 1996, only the 1990
data have been updated to be comparable to the more
_ .....„.,_ r,.. . . . .. .. ,, recent inventories.
Exhibit 2-18. PM-|o emissions in the U.S.,
1990 and 1996-2002
What the Data Show
A. Anthropogenic PM10 emissions by source category*b
Emissions (million tons)
3 o — •• -»• ro ro w c*
3U1OCJIOO1OU
/\.
^^^
Fuel combustion
^"---^
Industrial and other processes
On-road vehicles
Nonroad vehicles and engines
'90
'96 '97
'99 '00
'01
'02
Year
B. Relative amounts of PMiD
emissions Irom anthropogenic
and other sources, 2002b
Miscellaneous
and natural
sources
26%
Anthropogenic
14%
"Data are presented for 1990
and 1996-2002, as datasets
from these inventory years
are fully up-to-date. Data are
available for inventory years
1991-1995, but these data
have not been updated to
allow comparison with data
from 1990 and 1996-2002.
"Starting in 1999, EPA began
tracking condensable
particulate emissions
separately from filterable
particulate emissions. In
order to display data
generated using a consistent methodology, emissions of
condensable particulate from 1990 to 2002 are not included in
Panel A. However, condensable particulate emissions are
included in Panel B.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
PMi0 Emissions Trends
Estimated PM10 emissions from anthropogenic
sources decreased 29 percent nationally between
1990 and 2002 (Exhibit 2-18, panel A). Of these
sources, the fuel combustion category saw the largest
absolute decrease in emissions (422,000 tons; 35
percent), and the on-road vehicle sector showed the
largest relative decrease (47 percent; 183,000 tons).
PM10 emissions from the group of sources including
miscellaneous and natural sources and fugitive dust
were estimated to account for 86 percent of total
PM10 emissions (including condensables from
stationary and mobile sources) in 2002, the majority
of which was attributable to fugitive dust from roads
(Exhibit 2-18, panel B).
Changes in estimated anthropogenic PMi0 emissions
from 1990 to 2002 varied widely among EPA
Regions, ranging from an increase of 56 percent
(Region 8) to a decrease of 64 percent (Region 1)
(Exhibit 2-19).
»
'A/2 3 Emissions Trends
Estimated PM2 5 emissions from anthropogenic
sources decreased 27 percent nationally between
1990 and 2002 (Exhibit 2-20, panel A). Like PM10,
the largest absolute decline in PM2 5 was seen in the
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1
2
3
4
5
6
Exhibit 2-19. PM-io emissions in the U.S. by
EPA Region, 1990 and 1996-2002a
EPA Regions
'90
Year
aData are presented for 1990
and 1996-2002, as datasets
from these inventory years
are fully up-to-date. Data are
available for inventory years
1991-1995, but these data
have not been updated to
allow comparison with data
from 1990 and 1996-2002.
"Starting in 1999, EPA began tracking condensable paniculate
emissions separately from filterable paniculate emissions. In
order to display data generated using a consistent methodology,
emissions of condensable paniculate from 1999 to 2002 are not
included In this figure.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
Exhibit 2-20. PM2 5 emissions in the U.S.,
1990 and 1996-2002
A. Anthropogenic PM2.s emissions by source category*b
Emissions (million tons)
2.0
1.5
1.0
0.5
0.0
>
T
3C
A
Fuel combustion
^~~~-~-__
Industrial and other processes
On-road vehicles
Nonroad vehicles and engines
'96 '97 '98 '99 '00 '01 '0
Year
B. Relative amounts of PM2.5
emissions from anthropogenic
and other sources, 2002b
Miscellaneous
and natural
sources
33%
°\
Fugitive du
31%
Anthropogenic
36%
"Data are presented for 1990
and 1996-2002, as datasets
from these inventory years
are fully up-to-date. Data are
available for Inventory years
1991-1995, but these data
have not been updated to
allow comparison with data
from 1990 and 1996-2002.
"Starting in 1999, EPA began
tracking condensable
paniculate emissions
separately from filterable
paniculate emissions. In
order to display data
generated using a consistent methodology, emissions of
condensable paniculate from 1990 to 2002 are not Included in
Panel A. However, condensable paniculate emissions are Included
In Panel B.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
fuel combustion source category (347,000 tons; 38
percent), and the largest relative decline was in the
on-road vehicle category (54 percent; 175,000 tons).
Emissions from the group of miscellaneous and natural sources were estimated to account for 64 percent
of the total PM2 5 emissions (including condensables from stationary and mobile sources) nationally in
2002 (Exhibit 2-20, panel B).
Anthropogenic PM2 5 emissions decreased in all ten EPA Regions from 1990 to 2002, with percent
reductions ranging from 6 percent (Region 8) to 71 percent (Region 1) (Exhibit 2-21).
Indicator Limitations
10
11
12
13
14
• Comparable PM emissions estimates through the NEI are available only for 1990 and 1996-
2002. Data for 1991-1995 are not provided due to differences in emission estimation
methodologies from other inventory years which could lead to improper trend assessments.
• Because the emissions indicators focus on sources of anthropogenic origin, PM emissions
from miscellaneous sources (e.g., wildfires) are not included in the trend line. Details on
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Exhibit 2-21. PMa.s emissions in the U.S. by
EPA Region, 1990 and 1996-2002a'b
400
300
°
<&
200
100
'90 '96 '97 '98 '99 '00 '01 '02
Year
'Data are presented for 1990
and 1996-2002, as datasets
from these inventory years are
fully up-to-date. Data are
available for inventory years
1991-1995, but these data have
not been updated to allow
comparison with data from
1990 and 1996-2002.
bStarting in 1999, EPA began tracking condensable particulate
emissions separately from filterable particulate emissions. In
order to display data generated using a consistent methodology,
emissions of condensable particulate from 1999 to 2002 are not
included in this figure.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
30 Data Sources
emissions from these sources can be found
at
http://www.epa.gov/ttn/chief/eiinformation
.html.
The emissions data for PM are largely
based on estimates that employ emission
factors generated from empirical and
engineering studies, rather than on actual
measurements of PM emissions. Although
these estimates are generated using well-
established approaches, the estimates have
uncertainties inherent in the emission
factors and emission models used to
represent sources for which emissions have
not been directly measured.
The methodology for estimating emissions
is continually reviewed and is subject to
revision. Trend data prior to these revisions
must be considered in the context of those
changes.
The indicator tracks primary PM
emissions. Particles that form in the air
through secondary processes are not
included in this indicator, but are
considered in the PM Concentrations
indicator (p. 2-44).
Not all states and local agencies provide
the same data or level of detail for a given
year.
31 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
32 based on raw PM emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
33 (http://www.epa.gov/ttn/chief/net/2002inventory.html). This indicator aggregates the raw NEI data by
34 source type (anthropogenic or biogenic), source category, and EPA Region.
35 References
36 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
37
38 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
39
41 U.S. EPA. 2004. Air quality criteria for particulate matter (October 2004). EPA 600/P-99/002aF-bF.
42 Research Triangle Park, NC.
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NDICATOR: Ambient Concentrations of Participate Matte
2 Particulate matter (PM) is the general term used for a mixture of solid particles and liquid droplets found
3 in the air. Airborne PM comes from many different sources. Primary particles are released directly into
4 the atmosphere from sources such as cars, trucks, heavy equipment, forest fires, and burning waste.
5 Primary particles also consist of crustal material from sources such as unpaved roads, stone crushing,
6 construction sites, and metallurgical operations. Secondary particles are formed in the air from reactions
7 involving precursor chemicals such as sulfates (which are formed from sulfur dioxide emissions from
8 power plants and industrial facilities), nitrates (which are formed from nitrogen dioxide emissions from
9 cars, trucks, and power plants) and carbon (which comes from reactive organic gas emissions from cars,
10 trucks, industrial facilities, forest fires, and biogenic sources such as trees).
11 Ambient air monitoring stations throughout the country measure air concentrations of two size ranges of
12 particles: PM25 and PMi0. PM25 consists of "fine particles" with aerodynamic diameters less than or
13 equal to 2.5 urn. PMi0 includes both fine particles (PM2 5) and "coarse particles," which is the subset of
14 PMio that is larger than 2.5 urn,. The chemical makeup of particles varies across the U.S. For example,
15 fine particles in the eastern half of the U.S contain more sulfates than those in the West, while fine
16 particles in southern California, for example, contain more nitrates than those in other areas of the U.S.
17 Carbon is a substantial component of fine particles everywhere (U.S. EPA, 2004a).
18 Fine particles also have a seasonal pattern. PM25 values in the eastern half of the U.S. are typically higher
19 in the third calendar quarter (July-September) when sulfates are more commonly formed from sulfur
20 dioxide emissions from power plants in that part of the country. Fine particle concentrations tend to be
21 higher in the fourth calendar quarter in many areas of the West, in part because fine particle nitrates are
22 more readily formed in cooler weather, and wood stove and fireplace use produces more carbon.
23 Many recent epidemiologic studies show statistically significant associations of various ambient PM
24 indicators (e.g., coarse or fine particulate, short-term or long-term concentrations) with a variety of
25 cardiovascular and respiratory health endpoints, including mortality, hospital admissions, emergency
26 department visits, other medical visits, respiratory illness and symptoms, and physiologic changes in
27 pulmonary function (U.S. EPA 2004b). Sensitive groups that appear to be at greatest risk to such PM
28 effects include older adults, individuals with cardiopulmonary disease such as asthma or congestive heart
29 disease, and children (U.S. EPA, 2004b). Unlike other criteria pollutants, PM is not a single specific
30 chemical entity, but rather a mixture of particles from different sources with different sizes and chemical
31 compositions. Toxicological studies suggest that some airborne particles are more toxic than others, due
32 to differences in their chemical composition—a topic that is thoroughly reviewed in other publications
33 (e.g., U.S. EPA, 2004b).
34 PM also can cause adverse impacts to the environment. Fine particles are the major cause of reduced
35 visibility in parts of the U.S., including many National Parks and Wilderness Areas (the Regional Haze
36 indicator, p. 2-50). PM deposition affects vegetation and ecosystems by altering nutrient and chemical
37 cycles in soils and surface water. For example, deposition of particles containing nitrogen and sulfur may
38 change the nutrient balance and acidity of aquatic environments so that species composition and buffering
39 capacity change (the Lake and Stream Acidity indicator, p. 2-62). Some particles that deposit onto plant
40 leaves can corrode leaf surfaces or interfere with plant metabolism. PM also causes soiling and erosion
41 damage to materials, including monuments, statues, and other objects of cultural importance (U.S. EPA,
42 2004b).
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1 This indicator presents trends in PMi0 and PM2 5 concentrations, using averaging times consistent with the
2 pollutants' corresponding National Ambient Air Quality Standards (NAAQS). For PMi0, trend data from
3 1990 to 2004 are presented for the second maximum 24-hour average concentrations measured at the
4 trend sites during each calendar year. For PM2 5, trend data from 1999 to 2004 are presented for
5 seasonally-weighted annual average concentrations and for the 98th percentiles of 24-hour average
6 concentrations measured at the trend sites during each calendar year. Trend data are based on
7 measurements from two nationwide networks of monitoring stations: the National Air Monitoring
8 Stations (NAMS) and the State and Local Air Monitoring Stations (SLAMS). For both PM10 and PM2 5,
9 the indicator displays trends for the entire nation and for the ten EPA Regions.
10 The indicator's exhibits display the pollutants' NAAQS as points of reference. However, the fact that the
11 national values or those shown for EPA Regions fall below the standards does not mean that all
12 monitoring sites nationally or in any particular EPA Region also are below the standards. The indicator
13 displays trends in the number of the 489 PMi0 monitoring sites and 707 PM2 5 monitoring sites nationwide
14 that exceed the standards, but these statistics are not displayed for each EPA Region.
15 What the Data Show
16 PMio Concentration Trends
17 (1988-1989 PM10 data will be added)
18 In 2004, the national 24-hour PMi0 concentration was 31 percent lower than the average 1990 level
19 (Exhibit 2-22, panel A). Additionally, of the 489 sites comprising this trend (out of 808 total monitoring
20 sites that were operating in 2004), the number reporting PMi0 concentrations above the 24-hour standard
21 declined 88 percent between 1990 and 2004 (Exhibit 2-22, panel B). All EPA Regions experienced a
22 steady decrease in 24-hour PMi0 levels over this period (Exhibit 2-23). EPA Regions 9 and 10 showed the
23 greatest decreases since 1990.
24 Also shown in Exhibit 2-22 (panel A) are the 90th and 10th percentiles based on the distribution of annual
25 statistics at the monitoring sites. This provides additional graphical representation of the distribution of
26 measured concentrations across the monitoring sites for a given year. Thus, the graphic displays the
27 concentration range where 80 percent of measured values occurred for that year. (Note, this presentation
28 style also applies to panel A in Exhibits 2-24 and 2-26, discussed below.)
29 PM2.s Concentration Trends
30 Annual average PM25 concentrations in 2004 were the lowest since nationwide monitoring began in 1999
31 (Exhibit 2-24, panel A). The trend is based on measurements collected at 707 monitoring stations that
32 have sufficient data to assess trends over that period (U.S. EPA, 2003). The seasonally-weighted annual
33 average concentrations decreased 14 percent between 1999 and 2004. The number of monitoring sites in
34 this trend (707 out of 781 total sites that were operating in 2004) reporting violations of the annual
35 average PM2 5 standard declined 69 percent over this period (Exhibit 2-24, panel B).
36 Regional declines were greatest in portions of the West (EPA Region 9) and the Southeast (EPA Region
37 4), where annual average PM25 levels in 2004 were 21 percent and 18 percent lower than those in 1999,
38 respectively (Exhibit 2-25). However, annual average PM2 5 levels in the Rocky Mountains (EPA Region
39 8) were essentially unchanged over the period.
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Exhibit 2-22. Ambient 24-hour PM10
concentrations in the U.S., 1988-2004a
A. Ambient concentrations
30
NAAQS = 150 ug/m3
90% of sites have concentrations below this line
Average
A
Median
,
S 10% of sites have
a concentrations below this line
'90 '92 '94
'96 '98
Year
'00 '02 '04
B. Number of trend sites above NAAQS
'88 '90 '92 '94
1 2-23. Ambient 24-hour
PM10
itrations in the contiguous U.S. by EPA
\ 1988-20043
•a
09
i
»
o
s
o
NAAQS
>v
^^S&
~— — .
= 150 ug/m3
••— •
^S
R1
— R2
R3
-R4
-R5
R6
R7
R8
— R9
— R10
— Nat'l
'88 '90 '92 '94 '96 '98 '00 '02 '04
Year
"Coverage: 477 monitoring sites
in the EPA Regions (out of a total
of 808 sites measuring PM-io in
2004) that have sufficient data to
assess PM10 trends since 1988.
Data source: U.S. EPA, Air
Quality System, 2005
EPA Regions
'00 '02 '04
Coverage: 489 monitoring sites nationwide (out of a total of 808
sites measuring PM10 in 2004) that have sufficient data to assess
PM10 trends since 1988.
Data source: U.S. EPA, Air Quality System, 2005
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Exhibit 2-24. Ambient annual PM2.5
concentrations in the U.S., 1999-2004"
20
'99
300
•I1 £.250
•75 S 200
150
e S
A. Ambient concentrations
90% of sites have concentrations below this line
Median
*
Average
10% of sites have
concentrations below this line
'00
'01
'03
'04
B. Number of trend sites above NAAQS
'05
'99
'00
'01
'02 '03
Year
'04
'05
aCoverage: 707 monitoring sites nationwide (out of a total of 781
sites measuring PM2.5 in 2004) that have sufficient data to assess
PM2.5 trends since 1999.
Data source: U.S. EPA, Air Quality System, 2005
Exhibit 2-25. Ambient annual PM2.5
concentrations in the contiguous U.S. by EPA
Region, 1999-2004"
20
\-S 10
>. c
is 8 5
NAAQS = 15 ug/m3
'00
'01
'02 '03
Year
'04 '05
"Coverage: 691 monitoring
sites in the EPA Regions (out
of a total of 781 sites
measuring PM2.5 in 2004) that
have sufficient data to assess
PM2.5 trends since 1999.
Data source: U.S. EPA, Air
Quality System, 2005
EPA Regions
0
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1
2
3
4
5
6
In 2004, the average of 98th percentiles of 24-hour PM2s concentrations at the 707 monitoring sites used
for the trend was 11 percent lower than the average 1999 level (Exhibit 2-26, panel A). The number of
monitoring sites in this trend (707 out of 781 total sites that were operating in 2004) reporting violations
of the 24-hour PM2 5 standard declined 64 percent over this period (Exhibit 2-26, panel B). All EPA
Regions except Region 8 experienced decreasing 24-hour PM2 5 levels, and Regions 9 and 4 again showed
the largest declines (25 percent and 17 percent, respectively) (Exhibit 2-27).
Exhibit 2-27. Ambient 24-hour PM2.s
concentrations in the contiguous U.S. by EPA
Region, 1999-2004"
Exhibit 2-26. Ambient 24-hour PM2.5
concentrations in the U.S., 1999-2004"
A. Ambient concentrations
N_MQS_=_6_5ji_g/ni
90% of sites have concentrations below this line
r
10% of sites have
concentrations below this line
B. Number of trend sites above NAAQS
Coverage: 691 monitoring sites
in the EPA Regions (out of a total
of 781 sites measuring PM2.5 in
2004) that have sufficient data to
assess PM2.6 trends since 1999.
Data source: U.S. EPA, Air
Quality System, 2005
Coverage: 707 monitoring sites nationwide (out of a total of 781
sites measuring PM2.5 in 2004) that have sufficient data to assess
PM2.5 trends since 1999.
Data source: U.S. EPA, Air Quality System, 2005
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1 Indicator Limitations
2 • Because there are far more PM10 and PM2 5 monitors in urban areas than in rural areas, the
3 trends might not accurately reflect conditions outside the immediate urban monitoring areas.
4 • Potential biases may exist for some PM2 5 ambient concentration measurements due to losses
5 from volatilization of nitrates and other semi-volatile materials and retention of particle-
6 bound water associated with hygroscopic species.
7 • Due to the relatively small number of monitoring sites in some EPA Regions, the regional
8 trends are subject to greater uncertainty than the national trends. Some EPA Regions with low
9 average concentrations may include areas with high local concentrations, and vice versa.
10 • To ensure that long-term trends are based on a consistent set of monitoring sites, selection
11 criteria were applied to identify the subset of PM monitoring sites with sufficient data to
12 assess trends over the time frames covered by this indicator. Monitoring sites without
13 sufficient data are not included in the trend analysis. Some excluded monitoring sites reported
14 PM concentrations above the PM standard during the years covered by this indicator.
15 Data Sources
16 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
17 based on raw PM ambient air monitoring data in EPA's Air Quality System (AQS) (U.S. EPA, 2006)
18 (http://www.epa.gov/ttn/airs/airsaqs/). National and regional trends in this indicator are based on the
19 subset of PM monitoring stations that have sufficient data to assess trends over the period of record (i.e.,
20 since 1990 for PM10 and since 1999 for PM2 5).
21 References
22 U.S. EPA. 2006. Data from the Air Quality System. Accessed 2006.
23
24 U.S. EPA. 2004a. The particulate pollution report: current understanding of air quality and emissions
25 through 2003. EPA 454/R-04/002. Research Triangle Park, NC.
26 U.S. EPA. 2004b. Air quality criteria for particulate matter (October 2004). EPA 600/P-99/002aF-bF.
27 Research Triangle Park, NC.
28 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
29 EPA/454/R-03/005. Research Triangle Park, NC.
30
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NDICATOR: Regional Ha
2 Regional haze is the term describing visibility impairment that results from fine particles and their
3 precursors emitted by a variety of sources and activities (U.S. EPA, 2004a). Visibility impairment is
4 observed not only in urban areas, but also in many of the best known and most treasured National Parks
5 and Wilderness Areas, such as the Grand Canyon, Great Smoky Mountains, Mount Rainier, Shenandoah,
6 Yellowstone, and Yosemite National Parks (U.S. EPA, 2003). Visibility impairment occurs when air
7 pollution, both particles and gases, scatter and absorb light. Haze not only limits the distance one can see,
8 but also degrades the color, clarity, and contrast of scenes. As the PM Concentrations indicator (p. 2-44)
9 describes further, the same pollutants that impair visibility are also linked to serious health effects.
10 The particles that impair visibility include both primary and secondary pollutants. The primary pollutants
11 of concern are particles that are emitted directly into the atmosphere, such as dust from roads or soot
12 (elemental carbon) from combustion sources, such as wood combustion. Secondary pollutants of concern
13 are particles that form in the atmosphere from chemical reactions and physical processes, such as sulfates
14 (formed from sulfur dioxide emissions from power plants and other industrial facilities) and nitrates
15 (formed from nitrogen oxides emitted from power plants, automobiles, and other types of combustion
16 sources).
17 Humidity can increase the effect of pollution on visibility, causing some particles to become more
18 efficient at scattering light and impairing visibility (U.S. EPA, 2003). In the eastern U.S., where annual
19 average relative humidity levels are between 70 percent and 80 percent, reduced visibility mainly results
20 from secondarily formed sulfates and high humidity, along with a somewhat lower contribution from
21 organic carbon and nitrates (U.S. EPA, 2004b). The effect of humidity is particularly strong in summer.
22 Humidity is less of a factor in the West, as average values are generally between 50 percent and 60
23 percent. In western states, primary emissions from sources like wood smoke and nitrates contribute a
24 large percentage of the total particulate loading, though secondarily formed sulfates also contribute to
25 visibility impairment. Without the effects of anthropogenic sources of pollution, the natural visual range
26 in the U.S. would vary with location, and is estimated to range from 75 to 150 km (45 to 90 miles) in the
27 East and from 200 to 300 km (120 to 180 miles) in the West (U.S. EPA, 2003).
28 This indicator reports visibility data calculated from measurements of particulate matter constituents
29 collected at 38 monitoring sites between 1992 and 2004 at National Parks, Wilderness Areas, and other
30 protected sites under the Interagency Monitoring of Protected Visual Environments (IMPROVE) network.
31 Data are presented for 10 Eastern (east of 100° W longitude) sites and 28 Western (west of 100° W
32 longitude) sites. Visibility, or visual range, is calculated from the measured levels of different components
33 within airborne particles and these components' light extinction efficiencies. The algorithm includes an
34 adjustment for ammonium sulfate and ammonium nitrate to account for their adsorption of water vapor
35 from the atmosphere under elevated relative humidity conditions. The IMPROVE particle data are
36 generated by laboratory analysis of 24-hour duration filter samples collected at each site on a one-day-in-
37 three schedule. The indicators track visibility in three categories: worst visibility conditions refer to the
38 mean of the 20 percent worst visibility days; best visibility conditions refer to the mean of the 20 percent
39 best visibility days; and mid-range visibility conditions refer to the mean of the remaining 60 percent of
40 days.
41 What the Data Show
42 On average, the best visibility in the East, as calculated from the measured concentrations of components
43 of PM, is only slightly better than the worst visibility in the West (Exhibit 2-28). In 2004, the mean visual
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Exhibit 2-28. Visibility in selected National Parks and Wilderness Areas In the U.S., 1992-2004ab
A. Western U.S. B. Eastern U.S.
250
200
150
100
50
0
'9
rage:
oass
Best visibility days_^
Mid-range visibility days
Worst visibility days
Best visibility days
M'd-range v's'b' ity days
Worst v's'b'l'ty days
2 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '0
Year
Monitoring sites
28 monitoring sites in the western U.S. and 1 0 monitoring sites in the eastern U.S. with sufficient / . ^
ess visibility trends from 1992 to 2004. % . « • *
'Visual ranges are calculated from the measured levels of different components within airborne particles and
these components' light extinction efficiencies. West
Data source: Interagency Monitoring of Protected Visual Environments (IMPROVE) network, 2006
• . gl
* •*•*
1 range forthe worst days in the East was 31 km (19.3 miles), compared to 137 km (85.1 miles) for the best
2 visibility days. In the West, the mean visual range extended from 109 km (67.7 miles) on the worst days
3 to 260 km (161.6 miles) on the best days. In both regions, the average visual range increased since 1992
4 for worst, mid-range, and best visibility days. The increased visual ranges between 1992 and 2004 for
5 mid-range visibility days were 46 percent in the East and 14 percent in the West.
6 Indicator Limitations
7 • These data represent visibility in a sampling of selected National Parks and Wilderness Areas
8 and are not representative of other rural or urban areas.
9 Data Sources
10 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
11 based on raw ambient air monitoring data collected as part of the Interagency Monitoring of Protected
12 Visual Environments (IMPROVE) network (IMPROVE, 2006)
13 (http://vista.cira.colostate.edu/improve/Data/IMPROVE/summary_data.htm). Visibility trends in this
14 indicator are derived from the subset of IMPROVE monitoring stations outside of urban areas that have
15 sufficient data to assess trends between 1992 and 2004.
16 References
17 IMPROVE. 2006. Data from the Interagency Monitoring of Protected Visual Environments (IMPROVE)
18 network. Accessed 2006.
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1 U.S. EPA. 2004a. The participate pollution report: current understanding of air quality and emissions
2 through 2003. EPA/454/R-04/002. Research Triangle Park, NC.
3 U.S. EPA. 2004b. The ozone report: measuring progress through 2003. EPA/454/K-04/001. Research
4 Triangle Park, NC.
5 U.S. EPA. 2003. Latest findings on national air quality—2002 status and trends. EPA/454/K-03/001.
6 Research Triangle Park, NC.
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INDICATOR: Sulfur Dioxide Emissions
2 Sulfur dioxide (SO2) belongs to the family of sulfur oxide (SOX) gases. These gases are formed when fuel
3 containing sulfur (mainly coal and oil) is burned (e.g., for electricity generation) and during metal
4 smelting and other industrial processes. High concentrations of SO2 are associated with multiple health
5 and environmental effects (U.S. EPA, 2003). The highest concentrations of SO2 have been recorded in the
6 vicinity of large industrial facilities. Although relatively few people live in areas where SO2
7 concentrations exceed the National Ambient Air Quality Standards (NAAQS), a much larger number of
8 people live in PM2 5 non-attainment areas, and SO2 is a major precursor to PM2 5 which also has human
9 health and ecological effects (the PM Concentrations indicator, p. 2-44).
10 Health effects associated with SO2 depend on the exposure concentrations and durations, and on the
11 susceptibility of exposed populations. Asthmatics are much more susceptible to SO2 exposure than people
12 who do not have asthma (U.S. EPA, 1986). Effects associated with longer-term exposures to high
13 concentrations of SO2, in conjunction with high levels of PM, include respiratory illness, alterations in the
14 lungs' defenses, and aggravation of existing heart or lung disease. The most susceptible populations under
15 these conditions include individuals with cardiovascular disease or chronic lung disease, children, and
16 older adults (U.S. EPA, 1982).
17 Many other environmental concerns are associated with high concentrations of SO2. For example,
18 airborne SO2, along with NOX, contribute to acidic deposition (the Acid Deposition indicator, p. 2-56);
19 SO2 is a major precursor to PM2 5 (the PM Concentrations indicator, p. 2-44); and SO2 contributes to
20 impaired visibility (the Regional Haze indicator, p. 2-50). SO2 exposure also can harm vegetation by
21 increasing foliar injury, decreasing plant growth and yield, and decreasing the number and variety of plant
22 species in a given community. Finally, SO2 can accelerate the corrosion of natural and man-made
23 materials (e.g., concrete and limestone) that are used in buildings, statues, and monuments that are part of
24 the nation's cultural heritage (U.S. EPA, 1982).
25 This indicator presents SO2 emissions from traditionally inventoried anthropogenic source categories:
26 1) "Fuel combustion: selected power generators," which includes emissions from coal, gas, and oil-fired
27 power plants that are required to use continuous emissions monitors (CEMs) to report emissions as part of
28 the Acid Rain Program (ARP); 2) "Fuel combustion: other sources," which includes industrial,
29 commercial, and institutional sources, as well as residential heaters and boilers not required to use CEMs;
30 3) "Other industrial processes," which include chemical production and petroleum refining; 4) "On-road
31 vehicles," which includes cars, trucks, buses, and motorcycles; 5) "Nonroad vehicles and engines," such
32 as farm and construction equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft, and
33 others. Since a substantial portion of airborne SO2 comes from fossil fuel combustion in electric utilities,
34 this indicator includes the separate "Fuel combustion: selected power generators" category in addition to
35 the four categories presented in the other emissions indicators.
36 SO2 emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite of
37 data from many different data sources, including industry and numerous state, tribal, and local agencies.
38 Different data sources use different data collection methods, and many of the emissions data are based on
39 estimates rather than actual measurements. For major electric generating units, most data come from
40 continuous emissions monitors that measure actual emissions. For other fuel combustion sources and
41 industrial processes, data are estimated using emission factors. Emissions from on-road and nonroad
42 sources were estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
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1 NEI data have been collected since 1990 and cover all
2 50 states and their counties, B.C., the U.S. territories
3 of Puerto Rico and Virgin Islands, and some of the
4 territories of federally-recognized American Indian
5 nations. Data are presented only for 1990 and the years
6 from 1996 to 2002; prior to 1996, only the 1990 data
7 have been updated to be comparable to the more recent
8 inventories.
What the Data Show
10 National estimated SO2 emissions decreased 34
11 percent between 1990 and 2002 (from 23,060,000 to
12 15,260,000 tons) (Exhibit 2-29). This downward trend
13 resulted primarily from emissions reductions at
14 electrical utilities. Between 1990 and 2002, air
15 emissions from electric utilities have consistently
16 accounted for roughly two-thirds of the nationwide
17 SO2 emissions.
18 Net SO2 emissions declined in all EPA Regions
19 between 1990 and 2002 except in Region 6 where
20 there was a slight increase (Exhibit 2-30). Since 1996,
21 the largest percent reductions in SO2 emissions
22 were seen in Regions 9 (33 percent), 10 (30
23 percent), 1 (29 percent), and 5 (25 percent), and the
24 smallest reductions were observed in Regions 6 (7
25 percent) and 3(10 percent).
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Exhibit 2-29. SC>2 emissions in the U.S. by
source category, 1990 and 1996-2002"
Other industrial
processes
On-road and
nonroad
mobile
sources
Fuel combustion:
selected power generators
Fuel combustion: other sources \
'97
'98 '99
Year
'00
'01
'02
26 Indicator Limitations
Though emissions from most electric
utilities are measured directly using
continuous monitoring devices, SO2
emissions data for other source types
are based on estimates that employ
emission factors generated from
empirical and engineering studies.
Although these estimates are generated
using well-established approaches, the
estimates have uncertainties inherent in
the emission factors and emission
models used to represent sources for
which emissions have not been directly
measured.
Comparable SO2 emissions estimates
through the NEI are available only for
1990 and 1996-2002. Data for 1991-
1995 are not provided due to
"Data are presented for 1990 and 1996-2002, as datasets from
these inventory years are fully jp-to-date. Data are available for
inventory years 1991-1995, but these data have not been updated
to allow comparison with data from 1990 and 1996-2002.
bThis category includes emissions from only those power plants
required to use continuous emissions monitors under the Acid
Rain Program.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
Exhibit 2-30. SO2 emissions in the U.S. by EPA
Region, 1990 and 1996-2002*
I 5
1. 4
w
C. Q
g 3
'tn
1 2
-R1
-R2
—R3
-R4
-R5
—R6
R7
R8
-R9
-R10
'96 '97 '98 '99
Year
'01 '02
EPA Regions
and 1996-2002, as datasets
from these inventory years are
fully up-to-date. Data are
available for inventory years
1991-1995, but these data have
not been updated to allow
comparison with data from
1990 and 1996-2002.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
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1 differences in emission estimation methodologies from other inventory years which could
2 lead to improper trend assessments.
3 • SO2 emissions from "miscellaneous sources" are not included in the total emissions. Details
4 on emissions from miscellaneous sources can be found at
5 http: //www. epa. gov/ttn/chief/eiinformation .html.
6 • The methodology for estimating emissions is continually reviewed and is subject to revision.
7 Trend data prior to these revisions must be considered in the context of those changes.
8 • Not all states and local agencies provide the same data or level of detail for a given year.
9 Data Sources
10 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
11 based on raw SO2 emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
12 (http://www.epa.gov/ttn/chief/net/2002inventory.html). This indicator aggregates the raw NEI data by
13 source category and EPA Region.
14 References
15 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
16
17 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
18
20 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
21 EPA/454/R-03/005. Research Triangle Park, NC.
22 U.S. EPA. 1986. Second addendum to the air quality criteria for particulate matter and sulfur oxides
23 (1982): assessment of newly available health effects information. EPA/450/S-86/012. Research Triangle
24 Park, NC.
25 U.S. EPA. 1982. Air quality criteria for particulate matter and sulfur oxides. EPA/600/P-82/020a-c.
26 Research Triangle Park, NC.
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INDICATOR: Acid Deposition
2 Every year, millions of tons of sulfur dioxide and nitrogen oxides are emitted to the atmosphere as a result
3 of the burning of fossil fuels and from other high temperature sources (the Sulfur Dioxide Emissions
4 indicator, p. 2-53; the Nitrogen Oxides Emissions indicator, p. 2-23). These gases react with water,
5 oxygen, and oxidants to form acidic compounds, which may be carried hundreds of miles by the wind—
6 even across state or national borders. Acid deposition occurs when these compounds fall to the Earth in
7 one of two forms: wet (dissolved in rain, snow, and fog) or dry (solid and gaseous particles deposited on
8 surfaces during periods of no precipitation). While wet deposition is the more widely recognized form
9 (more commonly referred to as "acid rain"), dry deposition can account for 20 percent to 80 percent of
10 total acid deposition depending on location and climate (MACTEC Engineering and Consulting, 2005). In
11 the environment, acid deposition causes soils and water bodies to acidify, which can make the water
12 unsuitable for some fish and other wildlife. Some types of ecosystems, those with less "buffering"
13 capacity, are more sensitive to acid deposition than others.
14 Scientists often use acid neutralizing capacity (ANC), a measure of the amount of anions, protons, and
15 non-proton cations in the water, as an indicator of which lakes and streams are most sensitive to
16 acidification (NAPAP, 1991). Most surface waters in the West do not exhibit many symptoms of
17 acidification, because relatively small amounts of acid deposition occur in acid-sensitive regions. In the
18 Northeast and along the Appalachian Mountains, however, relatively high levels of acid deposition occur
19 in acid-sensitive regions, or regions without enough geochemical buffering capacity to prevent
20 acidification of surface waters by acid deposition (the Lake and Stream Acidity indicator, p. 2-62).
21 Therefore, reductions in acid deposition have the largest impact on acidification of lakes and streams in
22 those areas.
23 Acid deposition damages some trees, particularly at high elevations, and speeds the decay of buildings,
24 statues, and sculptures that are part of our national heritage (U.S. EPA, 2003). The nitrogen portion of
25 acid deposition also contributes to eutrophication in coastal ecosystems, the symptoms of which include
26 potentially toxic algal blooms, fish kills, and loss of plant and animal diversity. Acidification of lakes and
27 streams can increase the amount of methylmercury available in aquatic systems (Winfrey and Rudd,
28 1990). Finally, increased levels of sulfate in ground-level air, a phenomenon related to dry deposition, can
29 contribute to decreased visibility as well as a variety of human health problems (U.S. EPA, 2003).
30 Total acid deposition in this indicator is determined using wet deposition measurements and dry
31 deposition calculated from ambient air concentration measurements. Wet deposition is measured through
32 chemical analysis of rainwater collected at sites across the U.S. The primary source of wet deposition
33 information comes from the National Atmospheric Deposition Program/National Trends Network
34 (NADP/NTN). The chemical components of wet deposition include sulfate, nitrate, and ammonium. Dry
35 deposition is not measured directly. EPA's Clean Air Status and Trends Network (CASTNET) determines
36 dry deposition inferentially by measuring ambient air concentrations of acidic compounds and then
37 calculating deposition rates using a multi-layer model that depends on meteorological data collected at the
38 sites as well as local vegetative conditions (http://www.epa.gov/castnet/). Chemicals measured include
39 components of particulate matter (sulfate (SO4) and nitrate (NO3)), gaseous nitric acid (HNO3), sulfur
40 dioxide (SO2), and ammonium (NFL,). This indicator uses the three-year average from 1989-1991 as a
41 baseline, as this period immediately predates controls on sulfur and nitrogen oxide emissions mandated
42 by the 1990 Clean Air Act Amendments. Use of three-year average data helps ensure that trends reflect
43 actual changes in acid deposition, instead of shorter-term fluctuations in meteorological conditions.
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1 What the Data Show
2 Analyses of long-term monitoring data from the National Atmospheric Deposition Program (NADP)
3 show that wet deposition of both sulfur and nitrogen compounds has decreased over the last 15 years
4 (Exhibits 2-3 land 2-32).
5 Wet sulfate deposition decreased across much of the U.S. during the 1990s (Exhibit 2-31). The greatest
6 reductions in wet sulfate deposition occurred in the Mid-Appalachian region (Maryland, New York, West
7 Virginia, Virginia, and most of Pennsylvania) and the Ohio River Valley. Less dramatic reductions were
8 observed across much of New England and portions of the Southern Appalachians. Average regional
9 decreases in wet deposition of sulfate between the periods 1989-1991 (panel A) and 2002-2004 (panel B)
10 were approximately 36 percent in the Northeast, 32 percent in the Midwest, 24 percent in the Mid-
11 Atlantic and 19 percent in the Southeast.
12 Wet nitrate deposition decreased approximately 16 percent across the Northeast and 8 percent in the Mid-
13 Atlantic between the periods 1989-1991 (Exhibit 2-32, panel A) and 2002-2004 (panel B). Wet deposition
14 of inorganic nitrogen has not changed substantially in the rest of the country over this period.
15 As with wet deposition, total deposition (the sum of wet and dry deposition) decreased between 1989-
16 1991 and 2002-2004, and reductions were more substantial for sulfur compounds than for nitrogen
17 compounds (Exhibits 2-33 and 2-34). Note that total nitrogen deposition in this indicator does not include
18 nitrogen components, such as ammonia, which can be a significant portion of the dry deposition.
19
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Exhibit 2-31. Wet sulfate (SO42~) deposition in
the contiguous U.S., 1989-1991 and 2002-2004'
Exhibit 2-32. Wet nitrate (NOs) deposition in
the contiguous U.S., 1989-1991 and 2002-2004*
A. Average wet SO., deposition, 1989-1991
A. Average wet N03 deposition. 1989-1991
B. Average wet N03 deposition. 2002-2004
B. Average wet S04? deposition, 2002-2004
Coverage: 184
monitoring sites in
Coverage: 184
monitoring sites in
1989-1991 and 235
monitoring sites in
2002-2004.
Wet NOa deposition (kilograms
per hectare):
Wet S042 deposition (kilograms
per hectare):
1989-1991 and 235
monitoring sites in
2002-2004.
0 5 10 15 20 25 30 35 >40
Data source: National
Atmospheric
Deposition Program
(NADP), 2005
Data source: National
Atmospheric
Deposition Program
(NADP), 2005
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Exhibit 2-33. Total sulfur deposition in the contiguous U.S., 1989-1991 and 2002-2004'
A. Average total sulfur deposition, 1989-1991
i
1.3
tc
B. Average total sulfur deposition, 2002-2004
Coverage: 37 monitoring sites in 1989-1991
and 70 monitoring sites in 2002-2004.
Data source: National Atmospheric
Deposition Program (NADP). 2005. and
U.S. EPA, Clean Air Status and Trends
Network (CASTNet). 2005
Numbers indicate total sulfur deposition (kilograms per hectare)
averaged over a 3-year period.
* 1 o Sizes of circles indicate the relative magnitude ot total sulfur deposition
Colors in circles indicate the breakdown ot total sulfur deposition:
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Exhibit 2-34. Total nitrogen deposition in the contiguous U.S., 1989-1991 and 2002-2004
A. Average total nitrogen deposition. 1989-1991
Numbers indicate total nitrogen deposition (kilograms per hectare), averaged
over a 3-year period.
. -10 Sizes of circles indicate the relative magnitude of total nitrogen deposition,
Colors in circles indicate the breakdown ot total nitrogen deposition:
Dry nitrogen deposition "Wet nitrogen deposition
B. Average total nitrogen deposition, 2002-2004
Numbers indicate total nitrogen deposition (kilograms per hectare), averaged
over a 3-year period.
Sizes ot circles indicate the relative magnitude ot total nitrogen deposition.
Colors in circles indicate the breakdown ol total nitrogen deposition:
Dry HNOj" deposition • Dry N03" deposition • Wet N03" deposition
Dry IW deposition • Wet NH/ deposition
Coverage: 37 monitoring sites in 1989-1991 and 70 monitoring sites in 2002-2004.
Data source: National Atmospheric Deposition Program (NADP). 2005, and U.S. EPA, Clean Air Status and Trends Network (CASTNet), 2005
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1 Indicator Limitations
2 • Geographic coverage is limited, particularly for dry deposition (and thus total deposition as
3 well), but the concentration of sites in the Midwest and Northeast is justified by the fact that
4 acid rain is much more of a problem in those regions than it is in the West, Great Plains, or
5 Southeast.
6 • Measurement techniques for dry deposition have improved substantially, but characterization
7 of dry deposition still requires a combination of measurements and modeling, which has
8 inherent uncertainties. Further, dry deposition presented in this indicator does not include
9 contributions from deposition of gaseous ammonia.
10 Data Sources
11 Summary data in this indicator were provided by EPA's Office of Atmospheric Programs, based on raw
12 deposition data from two sources. Raw wet deposition data are from the National Atmospheric Deposition
13 Program/National Trends Network (NADP, 2006) (http://nadp. sws .uiuc.edu/). and raw dry deposition
14 data are from the Clean Air Status and Trends Network (U.S. EPA, 2006) (http://www.epa.gov/castnet).
15 This indicator aggregates raw data across 3-year periods to avoid influences from short-term fluctuations
16 in meteorological conditions, and wet deposition data were interpolated among monitoring stations to
17 generate the maps shown in Exhibits 2-31 and 2-32.
18 References
19 MACTEC Engineering and Consulting, Inc. 2005. Clean Air Status and Trends Network (CASTNET):
20 2004 annual report. Prepared for U.S. EPA, Office of Air and Radiation.
21 NADP. 2006. Data from the National Atmospheric Deposition Program/National Trends Network.
22 Accessed 2006.
23 NAPAP (National Acid Precipitation Assessment Program). 1991. 1990 integrated assessment report.
24 Washington, DC.
25 U.S. EPA. 2003. Latest findings on national air quality: 2002 status and trends. EPA/454/K-03/001.
26 Research Triangle Park, NC.
27 U.S. EPA. 2006. Data from the Clean Air Status and Trends Network. Accessed 2006.
28
29 Winfrey, M.R., and J.W.M. Rudd. 1990. Environmental factors affecting the formation of methyl mercury
30 in low pH lakes. Environ. Toxicol. Chem. 9(7):853-869.
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INDICATOR: Lake and Stream Acidity
2
3
4
5
6
7
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Acid deposition can have serious effects on aquatic ecosystems. For example, aquatic organisms in
acidified waters can develop calcium deficiencies that weaken bones and exoskeletons and cause eggs to
be weak or brittle. Acidified waters can impair the ability offish gills to extract oxygen from water and
change the mobility of certain trace metals (e.g., aluminum, cadmium, manganese, iron, arsenic,
mercury), which in turn can place fish and other species sensitive to these metals at risk (NAPAP, 1991).
The Acid Deposition indicator (p. 2-56) explains the factors that contribute to acid deposition and
describes how acid deposition patterns have changed over the last 15 years.
The susceptibility of a water body to acidification depends on the ability of the water and watershed soils
to neutralize the acid deposition it receives. The best measure of this ability is acid neutralizing capacity
(ANC), which characterizes the amount of dissolved compounds that will counteract acidity. All bodies of
water have a measurable acid neutralizing capacity. ANC depends largely on the surrounding watershed's
physical characteristics, such as geology, soils, and size. The ANC of a body of water reflects the relative
proportions of positive and negative ions entering the water from sources such as atmospheric inputs and
the soil and bedrock surrounding and underlying the water body. The higher the ANC, the more acid a
water body can neutralize and the less susceptible it is to acidification. As ANC approaches zero, the
ability to neutralize acidity decreases. Surface water with an ANC greater than 200 micro equivalents per
liter (jieq/L) is usually considered non-acidic; surface water with an ANC less than 50 (ieq/L is
considered highly sensitive to acidification (is often seasonally acidic); and surface water with an ANC
less than 0 (ieq/L is considered chronically acidic, meaning the watershed no longer has the capacity to
neutralize further acid deposition (U.S. EPA, 2003). ANC can be negative when anions exceed non-
proton cations (i.e., when there are free protons [FT ions] in solution).
The National Acid Precipitation Assessment Program identified several regions in the U.S. as containing
many of the surface waters sensitive to acidification (Exhibit 2-35). Where soil buffering capacity is poor,
lakes and streams may be vulnerable to acidification (NAPAP, 1991).
This indicator is derived from ANC measurements
on probability survey samples representing 5,617
lakes and 72,000 stream miles in the five
geographic regions shown in Exhibit 2-36. These
measurements were collected as part of the
Temporally Integrated Monitoring of Ecosystems
(TIME) project and on 120 additional acid-
sensitive lakes and 78 acid-sensitive streams in the
Long-Term Monitoring (LTM) project, for which
data were available between 1990 and 2000 (U.S.
EPA, 2003). The lakes sampled include only those
in areas potentially sensitive to acidification with
areas greater than 4 hectares. Smaller lakes
generally are not used in this type of assessment
because they are more likely to be naturally acidic,
although acid deposition can cause them to
become further acidified. This indicator focuses
only on the northeastern U.S.; because monitoring
Exhibit 2-35. Areas with acid-sensitive waters
in the contiguous U.S.
West
Data source: National Acid Precipitation Assessment Program
(NAPAP), 1991
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1 is not ongoing for western and southeastern water bodies, trend data for those parts of the country are not
2 available.
3 What the Data Show
4 Between 1990 and 2000, ANC in lakes in the Upper Midwest (northeastern Minnesota, northern
5 Wisconsin, and northern Michigan), in lakes in the Adirondack Mountains, and in streams in the Northern
6 Appalachians (southern New York, west-central Pennsylvania, and eastern West Virginia) increased to a
7 degree where many water bodies that were considered "chronically acidic" in 1990 were no longer
8 classified as such in 2000 (Exhibit 2-36, panels A, B, and D). Specifically, between 1990 and 2000, the
9 percent of chronically acidic water bodies decreased in the Adirondack Mountains (from 13.0 percent to
10 8.1 percent), in the Upper Midwest (from 2.9 percent to 0.9 percent), and in the Northern Appalachian
11 Plateau (from 11.8 percent to 8.5 percent). This trend suggests that surface waters in these areas are
12 beginning to recover from acidification, though acidic surface waters are still found in these regions.
13 The trend of increasing ANC in the Adirondack Mountains, the Upper Midwest, and the Northern
14 Appalachian Plateau during the 1990s corresponds with a decrease in acid deposition in each of these
15 regions (the Acid Deposition indicator, p. 2-56) and reduced air emissions of the main precursors to acid
16 deposition, which are sulfur dioxide (the Sulfur Dioxide Emissions indicator, p. 2-53) and nitrogen oxides
17 (the Nitrogen Oxides Emissions indicator, p. 2-23).
Exhibit 2-36. Lake and stream acidity in selected acid-sensitive regions in the U.S., 1990 and 2000
D. Northern
Appalachian Plateau
E. Ridge and Blue
Ridge Region
Data source: U.S. EPA, 2003
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1 The ANC in lakes in New England and streams in the Ridge and Blue Ridge Region (east-central
2 Pennsylvania, western Maryland, and western Virginia) have not risen from their 1990 levels (Exhibit 2-
3 36, panels C and E). Therefore, the number of water bodies classified as "chronically acidic" in these
4 regions remained essentially unchanged between 1990 and 2000.
5 Indicator Limitations
6 • ANC sampling is limited to five regions, concentrated in the Northeast. There is no coverage
7 in the Southeast, West, or much of the Midwest. These regions were chosen for sampling
8 because previous research has shown that they are among the most sensitive to acid
9 deposition due to the soils and other watershed characteristics. In addition, as the Acid
10 Deposition indicator (p. 2-56) shows, many of these regions receive the highest rates of acid
11 deposition in the U.S. For these two reasons the waters sampled are likely to be at the greatest
12 risk of becoming acidified.
13 • Interpreting trends for this indicator is complicated because multiple factors contribute to
14 changes in ANC levels. For example, in areas where watershed soil characteristics are
15 changing (e.g., decreases in concentrations of base cations in the soil), even dramatic
16 reductions in acid deposition will not necessarily result in large rebounds in ANC levels.
17 Data Sources
18 Summary data in this indicator were provided by EPA's Office of Atmospheric Programs and are taken
19 from a publication documenting how surface waters have responded to reduced air emissions of acid rain
20 precursors (U.S. EPA, 2003). Trends are based on data collected in two networks: the Temporally
21 Integrated Monitoring of Ecosystems (TIME) project and the Long-Term Monitoring project. Because
22 both networks are operated by numerous collaborators in state agencies, academic institutions, and other
23 federal agencies, the raw monitoring data are not available in a single publication or database. The trend
24 data in this indicator are based on observations documented in several publications (see pages 15-17 of
25 U.S. EPA, 2003).
26 References
27 NAPAP (National Acid Precipitation Assessment Program). 1991. Acid deposition: state of science and
28 technology, volume II, aquatic processes and effects. Washington, DC.
29 U.S. EPA. 2003. Response of surface water chemistry to the Clean Air Act Amendments of 1990.
30 EPA/620/R-03/001. Research Triangle Park, NC.
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NDICATOR: Percent of Days with Air Quality Index Values Greater Than 1
2 The Air Quality Index (AQI) provides information on pollutant concentrations of ground level ozone,
3 particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Formerly known as the
4 Pollutant Standard Index (PSI), the nationally uniform AQI is used by state and local agencies for
5 reporting daily air quality and air quality related health advisories to the public.
6 In 1999, the AQI was updated to reflect the latest science on air pollution health effects and to make it
7 more appropriate for use in contemporary news media (U.S. EPA, 2003a). It also serves as a basis for
8 community-based programs that encourage the public to take action to reduce air pollution on days when
9 levels are projected to be of concern. The index has been adopted by many other countries (e.g., Mexico,
10 Singapore, and Taiwan) to provide the public with information on air quality.
11 The AQI is based on pollutant concentration data measured by the State and Local Air Monitoring
12 Stations (SLAMS). The AQI is monitored in city groupings known as metropolitan statistical areas
13 (MSAs) which are defined by the Office of Management and Budget. For most pollutants in the index, the
14 concentration is converted into index values between 0 and 500, "normalized" so that an index value of
15 100 represents the short term, health-based standard for that pollutant as established by EPA (U.S. EPA,
16 1999). The higher the index value, the greater the level of air pollution and health risk. An index value of
17 500 reflects a risk of imminent and substantial endangerment to public health. The level of the pollutant
18 with the highest index value is reported as the AQI level for that day. An AQI value greater than 100
19 means that at least one criteria pollutant has reached levels at which people in sensitive groups may
20 experience health effects. A complete description of how AQI values are calculated and what they
21 represent is documented in many publications (e.g., U.S. EPA, 2003b).
22 This indicator is based on the percent of days across 93 large MSAs (500,000 people or more) during the
23 year that recorded an AQI greater than 100 at one or more monitoring sites in the MSA. While the AQI
24 indicator is calculated from ambient concentration data for criteria pollutants, this indicator's trends
25 should not be expected to mirror the trends in the other ambient concentration indicators, due to the
26 differing spatial coverage of monitoring stations across the various indicators. The percent of days with
27 AQI greater than 100 was calculated in two steps: (1) For each year, the total number of days with
28 AQI>100 in each of the 93 MSAs was summed in order to get a national total. (2) The national total was
29 then divided by the total number of days in the annual sample (365 x 93) to obtain the percentage of days
30 with AQI>100 in a year. Data are presented from 1990 to 2005. However, because meteorology can
31 strongly influence AQI values in a given year, the change in AQI over time is evaluated by comparing the
32 3-year average observation at the beginning of the period of record (i.e., 1990-1992) to the 3-year average
33 at the end (i.e., 2003-2005). Comparing 3-year averages reduces the potential for biases introduced by
34 years with unique meteorological conditions. The air quality data that go into the index consist of daily
35 (24-hour) measurements for PMi0 and PM2 5 and continuous (1-hour) measurements for CO, NO2, ozone,
36 and SO2. However, of these pollutants, only four (CO, ozone, PM, and SO2) usually exhibit AQI values
37 greater than 100. The data come from a subset of ambient monitoring sites that meet the trends
38 requirements in Appendix B of the 2003 National Air Quality and Emissions Trends Report (U.S. EPA,
39 2003a).
40 What the Data Show
41 The percent of days with AQI greater than 100 in 93 large MSAs based on all criteria pollutants decreased
42 from 4.5 percent over the 1990-1992 time frame to 3.2 percent over the 2003-2005 time frame (Exhibit 2-
43 37, panel A). The AQI data based on all criteria pollutants are not directly comparable over this time
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Exhibit 2-37. Percent of days with Air Quality
Index (AQI) greater than 100 in selected U.S.
metropolitan areas, 1990-2005"
A. AQI trend based on all criteria pollutants (1990-2005)
1999 was the first year PM2.5
was included in the AQI 2003-2005: 3-year
1990-1992:3-year \ average = 3.2%
average = 4.5%
frame, because PM2 5 measurements started to
factor into the index in 1999. For this reason, the
indicator also presents AQI trends based strictly
on ozone and PM2 5 measurements.
For the same subset of MSAs and time frame, the
percent of days with AQI values greater than 100
decreased from 4.4 percent to 2.1 percent
(Exhibit 2-37, panel B). Before PM2.5 became
part of the index in 1999, ozone typically
accounted for more than 90 percent of the days
with AQI greater than 100.
Between 1999 and 2005, PM25 accounted for
some of the days with AQI greater than 100.
From 1999 to 2001, 2.1 percent of days with AQI
greater than 100 occurred due to PM2 5
concentrations, with this contribution decreasing
to 1.4 percent from 2003 to 2005.
Exhibit 2-38. Percent of days with Air Quality
Index (AQI) greater than 100 in selected U.S.
metropolitan areas by EPA Region, 1990-2003""
90 '92 '94 '96 '98 '00 '02 '04
Year
B. AQI trend based on ozone (1990-20D5)
1990-1992:3-year
average = 4.4%
2003-2005: 3-year
average = 2.1%
C. AQI trend based
on PM2.5 (1999-2005)"
: 93 metropolitan
areas.
"Data for 1990-1998 are not
shown because 1999 was
the first year that PM2l6 was
included in the AQI.
'96 '98 '00 '02 '04
Year
2003-2005:3-year
average = 1.4%
1999-2001:3-year
average = 2.1%
Data source: U.S. EPA, Air
Quality System, 2006
Coverage: 93 metropolitan areas
1999 was the first year that
PM2 5 was included in the AQI.
Data source: U.S. EPA, Air
Quality System, 2005
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1 Trends in AQI between 1990 and 2003 varied across the ten EPA Regions (Exhibit 2-38). In EPA
2 Regions 2, 6, and 9, the percent of total days with AQI greater than 100 averaged over 2001-2003 was
3 lower than the percent of total days with AQI greater than 100 averaged over the 1990-1992 time frame.
4 In the other seven EPA Regions, the percent of total days with AQI greater than 100 increased between
5 these two time frames. However, as noted above, the AQI values for 1990-1992 and 2001-2003 are not
6 directly comparable, because PM2 5 measurements did not factor into AQI prior to 1999.
7 Indicator Limitations
8 • The AQI does not address hazardous air pollutants (HAPs).
9 • Air quality may vary across a single MSA. In assigning a single number for each pollutant in
10 each MSA, the AQI does not reflect this potential variation.
11 • The data for this indicator are limited to MSAs comprising urban and suburban areas with
12 populations greater than 500,000. Thus, this indicator does not reflect MSAs smaller than
13 500,000 or rural areas.
14 • The AQI does not show which pollutants are causing the days with an AQI of more than 100,
15 or distinguish between days >100 and days with much higher AQIs.
16 • This composite AQI indicator does not show which specific MSAs, or how many MSAs,
17 have problems—a specific number of days could reflect a few areas with persistent problems
18 or many areas with occasional problems.
19 Data Sources
20 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
21 based on AQI values computed from raw ambient air monitoring data for criteria pollutants found in
22 EPA's Air Quality System (U.S. EPA, 2006). Spreadsheets with the processed AQI data for the 93 MSAs
23 considered in this indicator are publicly available (http://epa.gov/air/airtrends/factbook.html). This
24 indicator aggregates the processed AQI data nationally and by EPA Region.
25 References
26 U.S. EPA. 2006. Data from the Air Quality System. Accessed 2006.
27
28 U.S. EPA. 2003a. National air quality and emissions trends report—2003 special studies edition.
29 EPA/454/R-03/005. Research Triangle Park, NC.
30 U.S. EPA. 2003b. Air Quality Index: a guide to air quality and your health. EPA-454/K-03-002.
31
32 U.S. EPA. 1999. Air quality index reporting, 40 CFR part 58.
33
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INDICATOR: Mercury Emissions
2 Mercury is an element that occurs naturally in the environment. However, many industrial processes, such
3 as coal combustion, medical and hazardous waste incineration, municipal waste combustion, gold mining,
4 and certain chemical manufacturing operations have increased the amount of mercury released to the air.
5 What happens to mercury after it is emitted depends on several factors: the form of mercury emitted, the
6 location of the emission sources, how high above the landscape the mercury is released (e.g., the height of
7 the stack), the surrounding terrain, and the weather. Depending on these factors, atmospheric mercury can
8 be transported over a range of distances before it is deposited, potentially resulting in deposition on a
9 local, regional, continental, or global scale. While some domestic anthropogenic mercury emissions are
10 deposited within the contiguous U.S., the majority of such emissions combine with anthropogenic
11 emissions from other countries and natural emissions worldwide to form a pool of mercury that circulates
12 globally (Seigneur et al, 2004; U.S. EPA, 1996).
13 Because it does not degrade in the environment, most mercury emitted to the atmosphere eventually
14 deposits onto land or water bodies. Through a series of chemical transformations and environmental
15 transport processes, airborne mercury that deposits to the Earth's surface can eventually accumulate in the
16 food web (the Lake Fish Tissue indicator, p. 3-107), most profoundly in those species near the top of the
17 food web (e.g., shark, swordfish). The Blood Mercury indicator (p. 5-79) describes the human health
18 effects associated with mercury exposure.
19 This indicator presents mercury emissions from the following categories: 1) "Industrial processes: gold
20 mining"; 2) "Industrial processes: hazardous waste incineration"; 3) "Industrial processes: electric arc
21 furnaces"; 4) "Industrial processes: chlorine production"; 5) "Industrial processes: medical waste
22 combustors"; 6) "Industrial processes: municipal waste combustors"; 7) "Industrial processes: other
23 sources," which includes chemical production and other miscellaneous industrial processes; 8) "Fuel
24 combustion: industrial, commercial, and institutional boilers"; and 9) "Fuel combustion: utility coal
25 boilers." In order to better characterize mercury emissions, this indicator presents different source
26 categories than other emissions indicators in the Report on the Environment, including separate categories
27 for utility coal boilers and various industrial processes that release mercury (e.g., medical waste
28 incineration, municipal waste combustion, hazardous waste incineration, gold mining).
29 Mercury emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite
30 of data from many different data sources, including industry and numerous state, tribal, and local
31 agencies. Different data sources use different data collection methods, and many of the emissions data are
32 based on estimates rather than actual measurements. For most fuel combustion sources and industrial
33 processes emissions are estimated using emission factors.
34 NEI data have been collected since 1990 and cover all 50 states and their counties, D.C., the U.S.
35 territories of Puerto Rico and Virgin Islands, and some of the territories of federally-recognized American
36 Indian nations. Data are presented for the baseline year (1990-1993) and the latest period for which data
37 are available (2002). The baseline period 1990 to 1993 represents a mix of years depending on data
38 availability for various source types. While NEI data for air toxics (including mercury) were also
39 compiled for 1996 and 1999, the methodology used in those years for air toxics differs considerably from
40 the methodology used in 1990-1993 and 2002 and therefore cannot be compared directly to those data.
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1 What the Data Show
2 Between 1990-1993 and 2002, annual
3 nationwide air emissions of mercury
4 decreased from 245 tons per year to
5 114 tons per year, a decrease of 54
6 percent (Exhibit 2-39). The decline in
7 mercury emissions is attributed
8 primarily to decreased emissions from
9 medical waste incinerators and
10 municipal waste combustors. In 2002,
11 coal-burning power plants were the
12 largest anthropogenic source of
13 mercury emissions to the air in the
14 U.S., accounting for 44 percent of all
15 domestic anthropogenic mercury
16 emissions.
Exhibit 2-39. Mercury emissions in the U.S. by source category,
1990-1993 and 2002
17 Indicator Limitations
18
19
20
21
22
23
24
25
Emissions (tons per year)
2 § S 8 1
Industrial processes
DGold mining
D Hazardous waste incineration
D Electric arc furnaces
D Chlorine production
• Medical waste incinerators
D Municipal waste combustors
D Other industrial processes
Fuel combustion
D Industrial, commercial, and
institutional boilers
D Utility coal boilers
1 990-1 993a 2002
Year
a1990-1993 is considered the baseline period for mercury emissions. The baseline period
spans multiple years due to the availability of emissions data for various source
categories. The data presented for the baseline period are annual emissions (tons per
year) and are therefore comparable to the 2002 data.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
• The emissions data in this
indicator are primarily
based on estimates, not
direct measurements. Although these estimates have inherent uncertainties, the data have
been generated using well-established estimation methods.
• The trend shown is based on nationwide aggregate data. Regional and state trends may be
different.
• Not all states and local agencies provide the same data or level of detail for a given year.
26 Data Sources
27 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
28 based on raw mercury emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006)
29 (http://www.epa.gov/ttn/chief/net/2002inventory.html). This indicator aggregates the raw NEI data by
30 source category.
31 References
32 Seigneur, C., K. Jayaraghavan, K. Lohman, P. Karamchandani, and C. Scott. 2004. Global source
33 attribution for mercury deposition in the United States. Environ. Sci. Technol. 38:555-569.
34 U.S. EPA. 2006. Data from the National Emissions Inventory. Accessed 2006.
35
36 U.S. EPA. 1996. Mercury study report to Congress, volumes I to VII. EPA/452/R-96/001b. Washington,
37 DC.
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NDICATOR: Air Toxics Emission
2 Toxic air pollutants, also known as air toxics or hazardous air pollutants (HAPs), are those pollutants that
3 are known or suspected to cause cancer or are associated with other serious health (e.g., reproductive
4 problems or birth defects) or ecological effects. Examples of air toxics include benzene, found in
5 gasoline; perchloroethylene, emitted from some dry cleaning facilities; and methylene chloride, used as a
6 solvent by a number of industries. Most air toxics originate from anthropogenic sources, including mobile
7 sources (e.g., cars, trucks, construction equipment), stationary sources (e.g., factories, refineries, power
8 plants), and indoor sources (e.g., building materials, cleaning solvents). Some air toxics are also released
9 from natural sources such as volcanic eruptions and forest fires. Secondary formation of certain air toxics,
10 such as acetaldehyde and formaldehyde, can also occur when precursor chemicals react in the
11 atmosphere. The Clean Air Act identifies 188 air toxics associated with industrial sources. Twenty of
12 these air toxics also are associated with mobile sources (U.S. EPA, 2003).
13 People who inhale certain air toxics at sufficient concentrations may experience various health effects,
14 including cancer, damage to the immune system, and neurological, reproductive (e.g., reduced fertility),
15 developmental, or respiratory health problems (CDC, 2005). Air toxics also can present risks through
16 other exposure pathways. For example, air toxics may deposit onto soils or surface waters, where they can
17 then enter the food web and may eventually be ingested by humans. Plants and animals also may be
18 harmed by exposures to air toxics (U.S. EPA, 2003).
19 Air toxics emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite
20 of data from many different data sources, including industry and numerous state, tribal, and local
21 agencies. Different data sources use different data collection methods, and many of the emissions data are
22 based on estimates rather than actual measurements. For most fuel combustion sources and industrial
23 sources, emissions are estimated using emission factors. Emissions from on-road and nonroad sources
24 were estimated using EPA-approved modeling approaches (U.S. EPA, 2005).
25 NEI data have been collected since 1990 and cover all 50 states and their counties, D.C., the U.S.
26 territories of Puerto Rico and the Virgin Islands, and some of the territories of federally-recognized
27 American Indian nations. The NEI includes baseline air toxics data for the period 1990-1993 and since
28 then has been updated every 3 years. The baseline period 1990 to 1993 represents a mix of years
29 depending on data availability for various source types. While NEI data for air toxics were also compiled
30 for 1996 and 1999, the methodology used in those years for air toxics differed considerably from the
31 methodology that was used in 2002. Therefore, the 1996 and 1999 data are not presented because
32 comparing the two inventories might lead to invalid conclusions.
33 This indicator first presents emissions data for all air toxics combined, both at the national level and
34 broken down into the ten EPA Regions. Consistent with the other emissions indicators, the national data
35 are organized into the following source categories: 1) "Stationary sources," which include fuel
36 combustion sources (coal, gas and oil-fired power plants, industrial, commercial, and institutional
37 sources, as well as residential heaters and boilers) and industrial processes (chemical production,
38 petroleum refining, and metals production) categories; 2) "Fires: prescribed burns and wildfires," for
39 insights on contributions from some natural sources; 3) "On-road vehicles" which include cars, trucks,
40 buses, and motorcycles; and 4) "Nonroad vehicles and engines," such as farm and construction
41 equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft, and others.
42 In addition to presenting emissions data aggregated across all 188 air toxics, the indicator presents
43 emissions trends for five individual air toxics: acrolein, benzene, 1,3-butadiene, ethylene dibromide, and
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Exhibit 2-40. Air toxics emissions in the U.S. by
source category, 1990-1993 and 2002
0
fo 7
£
£ 6
a.
IB
o 4
I 3
CO
o 2
8
E 1
LLJ
n
D Fires (prescribed
burns and
wildfires)
D Nonroad vehicles
and engines
D On-road vehicles
D Stationary
sources (not
including fires)
1990-1993"
2002
Year
a1990-1993 is considered the baseline period for air toxics
emissions. The baseline period spans multiple years due to the
availability of emissions data for various source categories. The
data presented for the baseline period are annual emissions (tons
per year) and are therefore comparable to the 2002 data.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
hydrazine. These compounds were selected for
display because EPA's 2002 National Air Toxics
Assessment estimates that these air toxics present
the greatest nationwide health risks (whether for
cancer or non-cancer endpoints) among the subset
of air toxics for which available emissions and
toxicity data supported an evaluation (U.S. EPA,
2006a). This indicator breaks the emissions data for
these five air toxics into multiple source categories,
with the most appropriate categories for display
purposes differing from one air toxic to the next.
What the Data Show
Trends Aggregated Across All 188 Air Toxics
According to NEI data, estimated annual emissions
for the 188 air toxics combined decreased 29
percent from 7.2 million tons per year in the
baseline period of 1990-1993 to 4.5 million tons
per year in 2002 (Exhibit 2-40). This downward
trend resulted primarily from reduced emissions
from stationary sources and on-road mobile
sources.
Exhibit 2-41. Air toxics emissions in the U.S. by
EPA Region, 2002
3. 0.6
0.2
0.0
3 4 5 6 7
EPA Region
9 10
Data source: U.S. EPA, National
Emissions Inventory (NEI), 2005
EPA Regions
€>
In 2002, air toxics emissions in the ten EPA
Regions ranged from 153,000 tons per year in
Region 1 to 1,150,000 tons per year in Region 4
(Exhibit 2-41). Regional trends cannot be
quantified, because a complete set of state and
local air toxics emissions data are not available for
the 1990-1993 baseline period.
Trends for Selected Air Toxics
Exhibit 2-42 shows emissions trends for five
compounds believed to account for the greatest
health risks that are attributed to air toxics,
according to a recent modeling study (U.S. EPA,
2006a). The five plots in this exhibit show how
emissions trends vary from compound to
compound. Estimated emissions decreased
between the baseline period (1990-1993) and 2002
for all five selected air toxics: acrolein (55 percent
decrease; see panel A), benzene (24 percent; panel
B), 1,3-butadiene (43 percent; panel C), ethylene
dibromide (62 percent; panel D), and hydrazine (82
percent; panel E).
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2-71
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Exhibit 2-42. Emissions of selected air toxics in the U.S. by source category, 1990-1993 and 2002"
B. Benzene emissions
A. Acrolein emissions
C- 70
? 60
s.
£ 50
0
•g 40
1 30
B.
« 20
1 10
HI Q
1990-1993" 2002
Year
D Other sources
n Nonroad vehicles
and engines
n On-road vehicles
D Structural fires
D Prescribed burns
and wildfires
C. 1,3-Butadiene emissions
S. 70
e/i
o ou
E 50
1 10
£ 30
«
§ 20
| 10
LU (,
D Other sources
D Nonroad vehicles and
engines
D Prescribed burns and
wildfires
D On-road vehicles
1990-1993° 2002
Year
E. Hydrazine emissions
c- 3j
S on
£ ic
c/l
= .„
§. 20
" 1S
0 1S
| 10
"" 5
n
D Hydrogen fluoride
production
• Miscellaneous organic
chemical manufacturing
n Other sources
n Industrial organic
chemical production
D Industrial inorganic
chemical production
D Organic liquid distribution
. 600
| 40°
SJ 300
& 200
| 100
UJ 0
I — I
n Residential wood
combustion
D Oil and natural gas
production
n Other sources
n Prescribed burns and
wildfires
Q Nonroad vehicles and
engines
n On-road vehicles
1990-1993°
2002
Year
D. Ethylene dibromide emissions
Emissions (tons per year)
= _^g§_S_SS_c
• Miscellaneous organic
chemical
manufacturing
n Industrial organic
chemical production
n Other sources
1990-1993°
2002
Year
"These five air toxics were selected for presentation because they
are estimated to present the greatest overall health risks
nationwide for cancer and non-cancer endpoints.
"1990-1993 is considered the baseline period for air toxics
emissions. The baseline period spans multiple years due to the
availability of emissions data for various source categories. The
data presented for the baseline period are annual emissions (tons
per year) and are therefore comparable to the 2002 data.
Data source: U.S. EPA, National Emissions Inventory (NEI), 2005
1 Indicator Limitations
1990-1993° 2002
Year
2
3
4
5
6
1
8
9
10
11
The emissions data are largely based on estimates. Although these estimates are generated
using well-established approaches, the estimates have inherent uncertainties. The
methodology for estimating emissions is continually reviewed and is subject to revision.
Trend data prior to any revisions must be considered in the context of those changes.
The indicator is an aggregate number that represents contributions from 188 different
chemicals with widely varying toxicities and human exposures. Therefore, the nationwide
trend for total air toxics and the resulting health effects likely differs from emissions trends
for specific chemicals. Similarly, because the indicator is a nationwide aggregate statistic, the
trend may not reflect emissions trends for specific locations.
Not all states and local agencies provide the same data or level of detail for a given year.
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1 • There is uncertainty associated with identifying which air toxics account for the greatest
2 health risk nationwide. Toxicity information is not available for every compound, and
3 emissions and exposure estimates used to characterize risk have inherent uncertainties.
4 Additional limitations associated with the National Air Toxics Assessment are well
5 documented (U.S. EPA, 2006a).
6 Data Sources
7 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
8 based on raw air toxics emissions data in EPA's National Emissions Inventory (NEI) (U.S. EPA, 2006b)
9 (http://www.epa.gov/ttn/chief/net/2002inventory .html). This indicator aggregates the raw NEI data by
10 source category, EPA Region, and selected air toxics.
11 References
12 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
13 environmental chemicals. NCEH Pub. No. 05-0570. Accessed September 9, 2005.
14
15 U.S. EPA. 2006a. 1999 national-scale air toxics assessment,
16 February.
17 U.S. EPA. 2006b. Data from the National Emissions Inventory. Accessed 2006.
18
19 U.S. EPA. 2005. Documentation for the final 2002 mobile National Emissions Inventory.
20
22 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
23 EPA/454/R-03/005. Research Triangle Park, NC.
24
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INDICATOR: Ambient Concentrations of Benzene
2 Benzene is an air toxic emitted from gasoline service stations, motor vehicle exhaust, and the burning of
3 coal and oil. In addition to being a common air pollutant, benzene may also contaminate water. Urban
4 areas generally have higher concentrations of benzene than other areas.
5 People exposed to benzene at sufficient concentrations may experience various health effects, including
6 cancer, damage to the immune system, as well as neurological, reproductive (e.g., reduced fertility),
7 developmental, respiratory, and other health problems. Plants and animals may also be harmed by
8 exposures to benzene (U.S. EPA, 2003).
9 Benzene is the most widely monitored air toxic. Data from the National Air Toxics Trends Sites
10 (NATTS) network is expected to provide trends information for other air toxics pollutants in the next
11 Report on the Environment.
12 This indicator reflects ambient concentrations in micrograms per cubic meter ((ig/m3) of benzene from
13 1994 to 2004, based on the annual arithmetic average. This indicator displays trends averaged over 35
14 urban monitoring sites that have consistent data for the period of record in Photochemical Assessment
15 Monitoring Stations (PAMS), Urban Air Toxics Monitoring (UATMP) Stations, and Non-Methane
16 Organic Compound (NMOC) Monitoring Stations.
17 What the Data Show
18 Benzene concentrations declined 61 percent from
19 1994 to 2004 (Exhibit 2-43).
20 Indicator Limitations
21
22
23
24
25
26
27
28
29
30
31
• Benzene data represent only 35 urban
sites in the U.S.
• Because of the limited number of sites
that are primarily located in urban
areas, Exhibit 2-43 does not
necessarily represent an overall
national trend in benzene
concentrations.
• Benzene, while an important air toxic,
represents only one of many air toxics
that may occur in air.
Exhibit 2-43. Ambient benzene concentrations
in the U.S., 1994-2004"
90% of sites have concentrations below this line
sites have concentrations below this line
'94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05
Year
'Coverage: 35 monitoring sites nationwide (out of a total of 251
sites measuring benzene in 2004) that have sufficient data to
assess benzene trends since 1994.
Data source: U.S. EPA, Air Quality System, 2005
32 Data Sources
33 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
34 based on raw benzene ambient air monitoring data in EPA's Air Quality System (AQS) (U.S. EPA, 2006)
35 (http://www.epa. gov/ttn/airs/airsaqs/). National trends in this indicator are based on the subset of benzene
36 monitoring stations that have sufficient data to assess trends since 1994.
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1 References
2 U.S. EPA. 2006. Data from the Air Quality System. Accessed 2006.
3
4
5 U.S. EPA. 2003. National air quality and emissions trends report—2003 special studies edition.
6 EPA/454/R-03/005. Research Triangle Park, NC.
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INDICATOR: Concentrations of Ozone-Depleting Substances
2 Ozone, a gas present throughout the Earth's atmosphere, is a pollutant at the Earth's surface but forms a
3 protective layer in the stratosphere, helping shield the Earth from the sun's ultraviolet (UV) radiation.
4 Exposure to UV-rays is associated with skin cancer, cataracts, and other human health and ecological
5 problems (U.S. EPA, 1996).
6 Starting in the late 1970s, stratospheric ozone levels were observed to be declining due to worldwide
7 releases of various human-produced chemicals referred to as ozone-depleting substances (ODS),
8 particularly halocarbons such as the long-lived chlorofluorocarbons (CFCs), bromine-containing halons,
9 and methyl bromide. Through rapid catalytic reactions with ozone, the chlorine and bromine from these
10 chemicals have depleted the protective ozone layer (the Ozone Levels over North America indicator, p. 2-
11 79).
12 Worldwide production and consumption of ODS is being progressively eliminated under the provisions of
13 the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer. Overtime, reducing the
14 atmospheric loading of ODS is expected to result in global increases in stratospheric ozone. However,
15 because some ODS gases have long atmospheric lifetimes, and because of pre-phaseout ODS stockpiling
16 for post-phaseout use, ambient concentrations of ODS have only recently begun to stabilize and in some
17 cases begun to decline. While some gases, like methyl chloroform, decay quickly in the atmosphere, other
18 gases, like CFCs and halons, have atmospheric lifetimes on the order of hundreds or thousands of years.
19 Measures of effective equivalent troposphere chlorine (EEC1) and effective equivalent stratospheric
20 chlorine (EESC) are commonly used to represent atmospheric concentrations of ODS. Both represent
21 ODS concentrations weighted by their potential to catalyze the destruction of stratospheric ozone relative
22 to the ability of chlorine to do so. EEC1 is the equivalent effective chlorine in the troposphere. (EESC is
23 typically derived by adding a 3-year time lag to EEC1 to account for the time it takes for emissions of
24 ODS at the Earth's surface to migrate to the stratosphere and cause stratospheric ozone depletion.)
25 This indicator presents trends in concentrations of tropospheric ODS as EEC1. The EEC1 trend is based on
26 measurements from the National Oceanic and Atmospheric Association (NOAA) Climate Monitoring and
27 Diagnostics Laboratory and estimates of halocarbon emissions from industrial and international sources
28 from 1995 to 2004. Concentrations of EEC1 are presented as weighted averages based on ground-based
29 measurements of mixing ratios5 since 1995 at the following remote locations: Alert, North West
30 Territories, Canada; Barrow, Alaska; Niwot Ridge, Colorado; Mauna Loa, Hawaii; American Samoa;
31 Cape Grim, Tasmania, Australia; and the South Pole (NOAA CMDL, 2003). Data on total EEC1 are also
32 available for 1992 and 1994, but these years' of monitoring are only presented in the chemical-specific
33 graphs because the monitoring did not include methyl bromide, a quantitatively important ODS. Because
34 most ODS have long atmospheric half-lives, the ODS concentrations shown in this indicator reflect past
35 and recent contributions from emissions sources within the U.S. and worldwide.
36
' The mixing ratio is the ratio of the partial pressure of a gas to the total atmospheric pressure.
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Exhibit 2-44. Global effective equivalent chlorine
concentrations, 1995-2005"
2,800
.|J 2,700
.° B
" S. 2,600
& g
-I-S 2,500
|| 2,400
LU C <
s
'95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05
Year
"Effective equivalent chlorine (EECI) is typically used to represent
atmospheric concentrations of ozone-depleting substances. The
EECI reflects contributions from multiple ozone-depleting
substances, weighted by their potential to catalyze the destruction of
stratospheric ozone.
Data source: NOAA/ESRL/GMD, 2006
^^^^^^^^^^^^^^^^^^^m
Exhibit 2-45. Global effective equivalent chlorine
concentrations of selected ozone-depleting
substances, 1992-2005"
1,400
'92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05
"Effective equivalent chlorine (EECI) is typically used to represent
atmospheric concentrations of ozone-depleting substances. The EECI
of ozone-depleting substances is calculated from the substances'
atmospheric concentrations and their potential to catalyze the
destruction of stratospheric ozone.
"The chlorofluorocarbons (CFCs) considered in this figure are CFC-11 ,
CFC-12,andCFC-113.
GThe halons considered in this figure are halon 1311 and halon 1201.
dThe hydrochlorofluorocarbons (HCFCs) considered in this figure are
HCFC-22, HCFC-141b, and HCFC-142b.
Data source: NOAA/ESRL/GMD, 2006
What the Data Show
Total effective equivalent chlorine (EECI) resulting
from ODS emissions reached its peak concentration in
the mid-1990s at slightly over 2,700 parts per trillion
of air by volume (pptv) and has slowly declined by
approximately 11 percent since then (Exhibit 2-44).
Although concentrations of CFCs and several other
individual ODS compounds have begun to decline,
concentrations of halons and
hydrochlorofluorocarbons (HCFCs) have not yet
stabilized.
Declines in EECI abundances of several ODSs in the
troposphere between 1992 and 2005 have contributed
to the decline in total EECI (Exhibit 2-45). EECI
attributed to methyl chloroform has decreased more
than 80 percent over this period due to decreased
emissions as well as its short atmospheric lifetime.
EECI associated with CFCs has decreased more
slowly—more than 3 percent from its peak
tropospheric concentration in 1995-1996. The slow
decay of CFCs is a result of continued emissions of
CFCs from stockpiles in developed countries,
continued use in developing countries, and their
longer atmospheric lifetimes. EECI from methyl
bromide (CH3Br) has decreased nearly 20 percent
from its peak in 1998; however, continued use of
methyl bromide in developing countries and in
developed countries through critical use exemptions
slows the decrease in EECI associated with this
compound. EECI from methyl bromide exhibits
seasonal variations, which likely results from the
seasonal use of this chemical as a soil fumigant.
Despite declines in concentrations of some
tropospheric ODS, others, including halons and
HCFCs, continue to increase (Exhibit 2-45). EECI
estimated from halon emissions has increased by more
than 50 percent from 1992 to 2005, and EECI
attributed to HCFCs in 2005 is more than 2.5 times
higher than that from 1992. These trends reflect
continued emissions of these ODS from stockpiles in
developed countries and continued production and
consumption in developing countries (and developed
countries for HCFCs), as well as the longer
atmospheric lifetimes of halons.
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1 Indicator Limitations
2 • The calculation of EEC1 depends on the understanding of the interactions and atmospheric
3 residence times of many different gases; incorrect knowledge about these factors could affect
4 trends in the EEC1.
5 • EEC1 is calculated by weighing individual ODS concentrations by the substances' abilities to
6 catalyze destruction of stratospheric ozone, or the ozone destruction potential. The ozone
7 destruction potentials used to transform the data have inherent uncertainties, which can affect
8 the trend analyses.
9 • Factors additional to trends in halocarbons affect trends in stratospheric ozone, including
10 changes in climate (e.g., temperature, winds), changes in emissions and concentrations of
11 trace gases like nitrous oxide and methane, and changes in aerosol loading such as occurs
12 after an explosive volcanic eruption.
13 Data Sources
14 Tropospheric concentrations of ODSs presented in this indicator are based on measurements made by
15 NOAA's Global Monitoring Division and summarized at an online data repository (NOAA, 2006)
16 (ftp://ftp.cmdl .noaa.gov/hats/Total_Cl_Br/). The trend in this indicator was developed from a 2006 data
17 file available from the repository, which updates tropospheric ODS concentrations previously reported in
18 the peer-reviewed literature (Montzka et al. 1999, 2003).
19 References
20 Montzka, S.A., J.H. Butler, B.D. Hall, D.J. Mondeel, and J.W. Elkins. 2003. A decline in tropospheric
21 organic bromine. Geophys. Res.Lett. 30(15): 1826.
22 Montzka, S.A., J.H. Butler, J.W. Elkins, T.M. Thompson, A.D. Clarke, and L.T. Lock. 1999. Present and
23 future trends in the atmospheric burden of ozone-depleting halogens. Nature 398(6729):690-694.
24 NOAA. 2006. Online repository of global tropospheric mixing ratios of ozone-depleting gases. Accessed
25 2006.
26 NOAA CMDL (National Oceanographic and Atmospheric Administration, Climate Monitoring and
27 Diagnostics Laboratory). 2003. Summary report no. 27. Boulder, CO.
28
29 U.S. EPA. 1996. Air quality criteria for ozone and related photochemical oxidants. EPA/600/P-93/004F-
30 cF. Research Triangle Park, NC.
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NDICATOR: Ozone Levels over North Amer
2 Ozone (O3) is a gas present throughout the Earth's atmosphere; 90 percent resides in the stratosphere, the
3 layer of the atmosphere that starts about 6 to 9 miles above the Earth's surface at mid-latitudes, and the
4 rest is located in the troposphere, the atmospheric layer that lies between the stratosphere and the Earth's
5 surface. The environmental and human health implications of ground-level ozone are very different from
6 those of ozone higher in the atmosphere, leading to the maxim: "Good up high, bad nearby" (U.S. EPA,
7 2003). In the troposphere, ozone poses both health and ecological risks, but the natural layer of ozone in
8 the stratosphere shields and protects the Earth's surface from the sun's harmful ultraviolet (UV) rays
9 which can in turn lead to more cases of skin cancer, cataracts, and other health problems (U.S. EPA,
10 1996).
11 Increases in surface UV radiation have been associated with reductions in total column ozone levels based
12 on spectral measurements at a number of sites in Europe, North America, South America, Antarctica, and
13 New Zealand (Kerr and McElroy, 1993; Booth and Madronich, 1994; WMO et al., 2003). For example,
14 measurements between 1989 and 1993 over Toronto indicated that for every 1 percent decrease in total
15 column ozone, after accounting for seasonal and daily variables not related to ozone, there was a
16 corresponding increase between 1.1 percent and 1.3 percent in erythemally active UV-B radiation (Kerr
17 and McElroy, 1993).
18 Ozone in the stratosphere is constantly being produced naturally from dissociation of oxygen molecules
19 by highly energetic UV solar radiation. While this ozone is being transported poleward and downward
20 through the natural motions of air in the stratosphere, it also is being naturally destroyed through catalytic
21 reactions involving primarily nitrogen and hydrogen oxides.
22 Releases of various human-produced chemicals, such as the long-lived chlorofluorocarbons, bromine-
23 containing halons, and methyl bromide (the Concentrations of Ozone-Depleting Substances indicator, p.
24 2-76) have depleted the levels of protective stratospheric ozone starting in the late 1970s, particularly at
25 mid- to high latitudes. The U.S. has been a major contributor to the global emissions of these halocarbons,
26 accounting for about a quarter of total worldwide emissions before the major ozone-depleting substances
27 (ODS) were banned in the 1990s. It takes about 3 years for emissions of ODS at the Earth's surface to
28 migrate to the stratosphere and cause stratospheric ozone depletion (WMO et al., 2003).
29 This indicator tracks trends in the deviation from pre-1980 levels in total annually-averaged ozone values
30 integrated over the 35° to 60°N latitude belt (the latitudes roughly corresponding to North America) from
31 1965 to 2005. The estimates are based on data from several different sources including ground-based and
32 satellite measurements. The data on total ozone from ground-based measurements are from a network of
33 surface stations, which are equipped with spectrophotometers. These instruments measure how thick the
34 ozone layer would be if compressed in the Earth's atmosphere (at sea level and at 0°C), where one
35 Dobson Unit (DU) is defined to be 0.01 mm thickness at standard temperature and pressure. Reliable data
36 from regular measurements at these stations are available extending back to the 1960s, although
37 geographical coverage is limited before the 1970s (Fioletov et al., 2002; WMO et al., 2003).
38 Near-continuous global total ozone data are available from satellite measurements beginning in 1979. The
39 first set of satellite data are obtained from the Total Ozone Mapping Spectrometer (TOMS). The TOMS
40 instrument measures total ozone using the "backscattered albedo," which is the ratio of the radiance
41 backscattered from the Earth's atmosphere to the extraterrestrial solar irradiance. The second dataset
42 consists of total ozone measurements from the Solar Backscatter Ultraviolet (SBUV) spectrometer
43 (Fioletov et al., 2002; WMO et al., 2003).
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1
2
3
4
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
In addition to the ground-based and satellite data, two merged datasets are presented for this indicator.
The Goddard merged ozone dataset and the National Institute of Water and Atmospheric Research
(NIWA) ozone dataset were derived using measurements from a number of satellite instruments (Fioletov
et al., 2002; WMO et al., 2003).
What the Data Show
There was little ozone change (beyond natural
variations such as those resulting from the 11-year
solar sunspot cycle) before the late 1970s, but
decreases in stratospheric ozone began to occur after
1979 (Exhibit 2-46). The ground-based data and
satellite data (TOMS, SBUV, Goddard and NIWA)
have similar ozone variations, with differences
typically less than 0.5 percent. The mid-latitude
decline of approximately 6 percent between 1979
and 1995 is in general agreement with previous
profile trend estimates from satellite and ground-
based records. For the mid-latitudes of the Northern
Hemisphere, the average of the total ozone levels for
the 3-year period from 1998 to 2001 is about 3
percent lower than the average for the 3-year period
from 1977 to 1980, and average total ozone levels
have not changed considerably between 2001 and
2005. While this indicator covers the entire 35° to
60°N latitude belt, ozone varies little by longitude
and the estimated 3 percent change in total ozone
levels can be taken to apply to North America.
Exhibit 2-46. Total ozone levels over North
America, 1965-2005ab
Ground-based data
Merged satellite data
GOME satellite data
SBUV-SBUV/2 satellite data
NIWA assimilated satellite
data
70 75 '80 '85 '90 '95 '00 '05
'Total ozone refers to the total ozone concentration in a column of air
between the Earth's surface and the top of the atmosphere.
bTrend data are representative of latitudes ranging from 35 degrees
North to 60 degrees North.
Data source: 1965-2003 data from WMO etal., 2003, and 2004-
2005 data from unpublished results provided by WMO
This 3 percent change over North America is very similar to the statistically significant globally-averaged
decrease in total ozone over the 1979 to 2001 period (WMO et al., 2003). The decrease in the mid-
latitudes of the Southern Hemisphere, by contrast, has been twice as high, associated with the springtime
"ozone hole" over Antarctica. The trends in this indicator are consistent with well understood seasonal
variations in ozone, and with natural variations such as those due to the 11-year solar cycle and the effects
of volcanic eruptions, suggesting that the long-term trends are those resulting from the emissions of ODS.
33 Indicator Limitations
34
35
36
37
38
39
Fioletov et al. (2002) used estimates of ozone changes from several different, independent
sources to derive the figure used for this indicator. Differences in the calibration of
instruments used to obtain the ground-based and satellite datasets together with interruptions
in the observational records produce datasets with measurement errors typically around a few
percent (WMO et al., 2003). The figure presented does, however, show good overall
agreement among the different data sources for changes in total ozone.
40 Data Sources
41 Summary data for this indicator were provided by the World Meteorological Organization (WMO). The
42 1965-2003 data in this indicator are taken from WMO's 2002 Scientific Assessment of Ozone Depletion
43 (WMO et al. 2003), which presents ozone data based on multiple sets of measurements (e.g., Fioletov et
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1 al., 2002). The 2004-2005 data in this indicator were not publicly available at the time this report went to
2 press, but they will be published in WMO's upcoming 2006 Scientific Assessment of Ozone Depletion.
3 References
4 Booth, R.C., and S. Madronich. 1994. Radiation amplification factors—improved formulation accounts
5 for large increases in ultraviolet radiation associated with Antarctic ozone depletion. In: Weiler, C.S., and
6 P.A. Penhale, eds. Ultraviolet radiation and biological research in Antarctica. Antarctic Research Series.
7 Washington, DC: American Geophysical Union, pp. 39-42.
8 Fioletov, V.E., G.E. Bodeker, J.B. Kerr, A.J. Miller, RD. McPeters, and R Stolarski. 2002. The global
9 ozone and zonal total ozone variations estimated from ground-based and satellite measurements: 1978-
10 2000. J. Geophys. Res. 107(D22).
11 Kerr, J.B., and C.T. McElroy. 1993. Evidence for large upward trends of ultraviolet-B radiation linked to
12 ozone depletion. Science 262:1032-1034.
13 U.S. EPA. 2003. Ozone: good up high, bad nearby. EPA/45 l/K-03/001. Washington, DC.
14 U.S. EPA. 1996. Air quality criteria for ozone and related photochemical oxidants. EPA/600/P-93/004F-
15 cF. Research Triangle Park, NC.
16 WMO (World Meteorological Organization), et al. 2003. Scientific assessment of ozone depletion: 2002.
17 Geneva, Switzerland.
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INDICATOR: Ozone and Participate Matter Concentrations for U.S. Counties in
the U.S./Mexico Border Region
3 The border between the U.S. and Mexico spans approximately 2,000 miles, from the Pacific Ocean to the
4 Gulf of Mexico. The area is subjected to a unique blend of increased industrial development (especially
5 on the Mexico side of the border), intense pressures because of the shifting and growing population
6 related to this development, and an arid climate that can exacerbate many air quality problems. Ozone and
7 particulate matter are air pollutants of particular concern. Rapid population growth in urban areas of the
8 (U.S./Mexico) border has resulted in unplanned development, greater demand for land and energy, traffic
9 congestion, increased waste generation, overburdened or unavailable waste treatment and disposal
10 facilities, increased frequency of chemical emergencies, and had had an adverse impact on air quality
11 (U.S. EPA, 2003).
12 Ground-level ozone is harmful to both human health and the environment (the Ozone Concentrations
13 indicator, p. 2-32). Although some industrial sources release ozone directly into the environment, most
14 ground-level ozone forms from chemical reactions involving nitrogen oxides (NOX), volatile organic
15 compounds (VOCs), and sunlight. Ozone levels are typically highest during the afternoon hours of the
16 summer months, when the influence of direct sunlight is the greatest (U.S. EPA, 2006a).
17 Particulate matter (PM) is the general term used for a mixture of solid particles and liquid droplets found
18 in the air. Primary PM is released directly from emissions sources into the atmosphere, while secondary
19 PM is formed in the air from reactions involving precursor chemicals (e.g., nitrogen oxides, sulfur
20 dioxide, particle-producing organic gases). Ambient air monitoring stations measure air concentrations of
21 two size ranges of particles: PM2s (fine particles with aerodynamic diameter less than or equal to 2.5
22 micrometers ((im)) and PMi0 (both fine particles (PM2 5) and coarse particles with aerodynamic diameters
23 between 2.5 and 10 (im). Exposure to coarse particles can aggravate respiratory conditions such as
24 asthma, and exposure to fine particles is associated with various additional human health effects (the PM
25 Concentrations indicator, p. 2-44) (U.S. EPA, 2004).
26 This indicator shows trends in the design values for ozone and particulate matter in the U.S. counties at
27 the U.S./Mexico border area in comparison to U.S. national trends. These trends are shown for the longest
28 duration of time supported by the underlying monitoring data. The ozone design value is defined as a 3-
29 year average of the fourth highest daily maximum in each year. The design value for PMi0 is the 3-year
30 average of the second maximum 24-hour concentrations, and the design value for PM2.5 is the 3-year
31 average of the seasonally-weighted annual mean concentration. This indicator establishes a baseline for
32 measuring against future air quality levels and is based on all monitoring stations that operated on the
33 U.S. side of the border during this time period.
34 In EPA Region 6, ozone monitoring data from border locations were collected in Dona Ana County in
35 New Mexico, and El Paso, Brewster, Webb, Hidalgo, and Cameron Counties in Texas. In EPA Region 9,
36 ozone monitoring data from border locations were collected in the Counties of Cochise, Pima, and Yuma
37 in Arizona and Imperial and San Diego in California. PMi0 sampling data for EPA Region 6 are from
38 Cameron, Hidalgo, Webb and El Paso Counties in Texas and Dona Ana, Luna, and Grant Counties in
39 New Mexico. PM2 5 data were available for all of the above counties except for Luna County, New
40 Mexico. For EPA Region 9, PM10 monitoring data were collected in the Counties of Cochise, Pima, Santa
41 Cruz, and Yuma in Arizona and Imperial and San Diego in California. For EPA Region 9, PM2 5
42 monitoring data were collected in the Counties of Cochise, Pima, and Santa Cruz in Arizona and Imperial
43 and San Diego in California.
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Exhibit 2-47. Ambient ozone, PMio, and PMa.s concentrations in U.S. counties in the U.S.-Mexico border
area, 1986-2004"
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A. Ozone concentrations (1986-2004)
'90-'92 W-'Qe •98-00
Avaraging period
B. PM10 concentrations (1990-2004)
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"Coverage: 27 ozone monitoring
sites, 51 PM-io monitoring sites,
and 16 Plv^s monitoring sites
located in U.S. counties along the
U.S.-Mexico border that have
sufficient data to assess trends
over the corresponding time
frames that these pollutants were
monitored.
Data source: U.S. EPA, Air Quality
System, 2005
Counties with ambient air monitoring sites included in this indicator
1 What the Data Show
Trends for 8-Hour Ozone Concentrations
3 In EPA Region 6, average border ozone concentrations decreased by 11 percent between the 1986-1988
4 and 1992-1994 time periods and by 3 percent between the 1993-1995 and 2002-2004 periods, which was
5 similar to the national decreases of 9 percent and 3 percent, respectively (Exhibit 2-47, panel A). In EPA
6 Region 9, however, border ozone concentrations increased by 2 percent between the 1986-1988 and 1992-
7 1994 time periods but decreased by 11 percent between the 1993-1995 and 2002-2004 periods.
8 Trends for 24-Hour PM] 0 Concentrations
9 In EPA Region 6, the average second maximum 24-hour PMi0 concentrations at border monitoring sites
10 varied considerably from year to year, most likely due to variation in meteorological conditions (e.g.,
11 rainfall, wind speed) and soil erosion (Exhibit 2-47, panel B). In EPA Region 9, on the other hand,
12 corresponding PMi0 concentrations at border monitoring sites did not exhibit such strong temporal
13 variations, and the average second maximum 24-hour concentration at border monitoring sites for the
14 2002-2004 time frame was only slightly lower than that for the 1990-1992 time frame.
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1 Trends for Annual Average PM2.s Concentrations
2 Mean annual ambient PM2 5 concentrations increased by 16 percent in the border counties of EPA Region
3 6 between 1999-2001 and 2002-2004, but decreased by 16 percent in the border counties of EPA Region
4 9 (Exhibit 2-47, panel C). Mean annual ambient PM2 5 concentrations decreased 9 percent nationwide
5 over the same period.
6 Indicator Limitations
7 • Many counties along the U.S./Mexico border do not have ambient air quality monitors; these
8 counties are not characterized by this indicator.
9 • This indicator does not include data from the Mexican side of the border. When the technical
10 review concludes the quality of this data is appropriate for the intended use, the indicator will
11 be updated.
12 • Short-term trends in PMi0 concentrations are often highly dependent on meteorological
13 conditions. The maximum concentration for a given site can be influenced by wind-blown
14 dust and will exhibit considerable variations from day to day. Trends over the longer term are
15 far less likely to be influenced by unusual meteorological conditions.
16 • The long-term ozone trends are derived from an increasing number of monitors over the
17 course of time from 1986-2004, but an analysis of the limited number of border sites that
18 have full periods of record show that the slopes of the trends are similar to those in this
19 indicator.
20 • Mean air pollutant concentrations may mask higher values in some areas along the border and
21 in the nation.
22 • Because most of the monitoring sites are located in urban areas, the trends might not
23 accurately reflect conditions outside the immediate urban monitoring areas.
24 Data Sources
25 Summary data in this indicator were provided by EPA's Office of Air Quality Planning and Standards,
26 Region 6, and Region 9. These summaries were based on raw ozone and PM ambient air monitoring data
27 in EPA's Air Quality System (U.S. EPA, 2006b) (http://www.epa.gov/ttn/airs/airsaqs/). Trends in this
28 indicator are based on the subset of ozone and PM monitoring stations located in counties along the
29 U.S./Mexico border that have sufficient data to assess trends over the period of record.
30 References
31 U.S. EPA. 2006a. Air quality criteria for ozone and related photochemical oxidants. EPA/600/R-
32 05/004aF-cF. Research Triangle Park, NC.
33 U.S. EPA. 2006b. Data from the Air Quality System. Accessed 2006.
34
35 U.S. EPA. 2004. Air quality criteria for particulate matter (October 2004). EPA 600/P-99/002aF-bF.
36 Research Triangle Park, NC.
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1 U.S. EPA. 2003. Border 2012: U.S.-Mexico environmental program. EPA/160/R-03/001. Washington,
2 DC.
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INDICATOR:
5
Ambient Concentrations of Manganese Compounds in EPA Region
3 Manganese is a naturally occurring metal that is ubiquitous in the environment. Exposure to low levels of
4 manganese in the diet is considered to be nutritionally essential for people and animals (ATSDR, 1997).
5 However, exposures to elevated concentrations of manganese are harmful to human health and have been
6 associated with subtle neurological effects, such as slowed eye-hand coordination. Manganese
7 compounds are hazardous air pollutants emitted by iron and steel production plants, power plants, coke
8 ovens, and many smaller metal processing facilities. Manganese also may be contributed in border
9 communities by vehicles using Canadian fuel with the additive methylcyclopentadienyl manganese
10 tricarbonyl (MMT).
11 Although manganese compounds are air pollutants of concern nationwide, they are of special concern in
12 EPA Region 5. The 1999 National Emissions Inventory showed that Region 5 had the highest manganese
13 emissions of all EPA Regions, contributing 36.6 percent of all manganese compounds emitted nationwide
14 (U.S. EPA, 2005a). Emissions from industrial sources in Region 5 occurred from various facilities, such
15 as those that manufacture steel or process iron ores and alloys for steelmaking. Between 1988 and 2003,
16 manganese emissions from point sources declined both nationally (26.2 percent) and in EPA Region 5
17 (36.7 percent). Year-to-year variability in manganese emissions is high, however, and recent emissions
18 data (1996-2003) suggest a weaker trend: emissions dropped 7.6 percent and 12.4 percent nationwide and
19 in EPA Region 5, respectively (U.S. EPA, 2005b).
20 EPA's National-Scale Air Toxics Assessment (NATA) is intended to provide a better understanding of
21 the health risks resulting from inhalation exposure to air toxics. Based on 1999 emission inventories, the
22 most recent NATA results (U.S. EPA, 2006a) identify manganese compounds as the largest contributor to
23 neurological non-cancer health risk in the U.S. Modeled estimates of ambient manganese compounds in
24 all 3,222 U.S. counties show that among the 50 counties with the highest concentrations nationwide, 20
25 are located in EPA Region 5.
26 This indicator presents ambient concentrations of manganese compounds measured as total suspended
27 particulates (TSP) by direct monitoring. This indicator addresses manganese in the TSP fraction (not
28 PMio or PM2 5) because it is the most complete dataset in EPA Region 5 in terms of geographic and
29 temporal coverage. TSP metals data have been commonly used in human health risk assessments. EPA
30 recently has begun to recommend PMi0 as the most appropriate fraction for evaluating people's exposure
31 to toxic metals (U.S. EPA, 2002), but PMi0 metals data are sparse at this time, both nationally and in EPA
32 Region 5. Data from a limited number of sites in AQS with collocated PM10 and TSP speciation monitors
33 suggest that the proportion of manganese in PMi0 versus TSP is about 50 percent at most sites and can be
34 as high as 75 percent. TSP manganese data therefore should be considered a conservative estimate of
35 PM10 manganese exposures. PM25 metals data are plentiful since the establishment of the Speciation
36 Trends Network (STN) in 2000, but this size fraction is believed to underestimate human exposures.
37 Data were considered for 53 monitoring sites in EPA Region 5 that had a complete year of data reported
38 to the Air Quality System (AQS) national database in 2004. Average manganese concentrations were
39 calculated for each monitoring site. A concentration trend was determined using a subset of 21 of the
40 monitoring sites with four or more complete years of data between 2000 and 2004. As annual average
41 concentrations are representative of long-term inhalation exposures, the ambient monitoring data are
42 displayed in comparison with the manganese Reference Concentration (RfC). The RfC is an estimate of a
43 chronic inhalation exposure that is likely to be without appreciable risk of adverse non-cancer effects
44 during a lifetime. The RfC for manganese is 0.05 micrograms per cubic meter (ug/m3), based on
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1 impairment of neurobehavioral function in people. At exposures increasingly greater than the RfC, the
2 potential for harmful effects increases (ATSDR, 1997; U.S. EPA, 1999). Monitoring sites were classified
3 into different categories based on land use as defined in AQS.
4 What the Data Show
5 In 2004 the median average annual ambient concentrations of manganese as TSP in EPA Region 5 were:
6 0.035 (ig/m3 at the 16 residential sites, 0.036 (ig/m3 at the 14 sites in commercial or high-traffic areas, and
7 0.049 (ig/m3 at the 19 industrial sites (Exhibit 2-48). The median average annual ambient concentration of
8 manganese at 4 predominantly agricultural and forest sites in EPA Region 5 was 0.02 (ig/m3, but this is
9 not depicted in the figure due to the limited number of monitoring sites to characterize a distribution.
10 Greater concentration differences were observed in the 90th percentile values, with average concentrations
11 ranging from 0.10 (ig/m3 at the residential sites to 0.33 (ig/m3 at the predominantly industrial sites.
12 Eighteen of the 53 sites had average manganese concentrations higher than the RfC; 10 of these sites were
13 categorized as industrial, 4 commercial or mobile, and 4 residential.
14 The median annual manganese concentration averaged across 21 trend sites showed a 15 percent decline
15 between 2000 and 2004 (Exhibit 2-49). Additional years of data will be needed to confirm this apparent
16 trend. The trend sites had the following land use designations: commercial and mobile (6 sites), industrial
17 (9 sites), residential (6 sites), and agricultural and forest (no sites).
Exhibit 2-48. Ambient manganese
concentrations in EPA Region 5 by land use
category, 2004ab
0.4
-------
1 Indicator Limitations
2 • AQS data represent several sites per state, but do not have full geographic or temporal
3 coverage. Some emissions "hotspots" are included, while others may exist that have not been
4 monitored.
5 • The land use categories are only generally indicative of the area represented by an ambient air
6 monitor. For example, a site categorized as "industrial" may adjoin a densely populated
7 community where many residents are exposed to ambient pollution.
8 Data Sources
9 Summary data in this indicator were provided by EPA Region 5, based on raw ambient air monitoring
10 data for manganese compounds reported in EPA's Air Quality System (U.S. EPA, 2006b)
11 (http://www.epa.gov/ttn/airs/airsaqs/). Trends in this indicator are based on the subset of monitoring
12 stations located in EPA Region 5 that have sufficient manganese concentration data to assess trends over
13 the period of record.
14 References
15 ASTDR (Agency for Toxic Substances and Disease Registry). 1997. Toxicological profile for manganese
16 (update). Draft for public comment. Atlanta, GA: U.S. Department of Health and Human Services.
17 U.S. EPA. 2006a. 1999 national-scale air toxics assessment,
18 February.
19 U.S. EPA. 2006b. Data from the Air Quality System. Accessed 2006.
20
21 U.S. EPA. 2005a. 1999 National Emissions Inventory data, August.
22 U.S. EPA. 2005b. 1999 Toxics Release Inventory data. December.
23 U.S. EPA. 2002. Quality assurance guidance document—model quality assurance project plan for the
24 national air toxics trends stations. Washington, DC.
25 U.S. EPA. 1999. Integrated Risk Information System (IRIS) on manganese. Washington, DC.
26
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1 2.2.3 Discussion
2 What These Indicators Say About Trends in Outdoor Air Quality and Their
3 Effects on Human Health and the Environment
4 Criteria Pollutants and Their Precursors
5 Because of statutory monitoring and reporting requirements, criteria pollutants have some of the most
6 extensive data available to support National Indicators for emissions and ambient air concentrations.
7 Nationwide, air emissions of every criteria pollutant (or their corresponding precursors) have decreased
8 between 1990 and 2002—the period of record covered by the National Emissions Inventory. During that
9 time frame, substantial decreases in air emissions were observed for carbon monoxide, nitrogen oxides,
10 particulate matter, sulfur dioxide, and volatile organic compounds. Even more pronounced emissions
11 reductions occurred for lead, but this decrease extends back to the 1970s. With few exceptions, downward
12 trends in criteria pollutant emissions were observed in the 10 EPA Regions, similar to the corresponding
13 national trends.
14 Consistent with the emissions trends, every criteria pollutant showed decreasing ambient air
15 concentrations based on aggregate measurements from the nation's ambient air monitoring system, which
16 measures levels of air pollution primarily in urban and suburban areas. The magnitude of air quality
17 improvements, observed both nationally and in all 10 EPA Regions, varies across pollutants. Carbon
18 monoxide, lead, and nitrogen dioxide concentrations decreased considerably between 1980 and the
19 present, and ambient concentrations of these three pollutants in most or all areas in the U.S. are now
20 below the corresponding air quality standards that protect human health and the environment. In contrast,
21 air quality improvements for ozone and particulate matter (particularly PM2 5) were less pronounced; and,
22 based on monitoring data collected in 2005 and reported in EPA's Air Quality System, ambient
23 concentrations in 68 metropolitan statistical areas where approximately 128 million people live did not
24 meet the health-based NAAQS for ozone, particulate matter, or both pollutants. In short, every criteria
25 pollutant has showed improving air quality over the past one or two decades, but the progress has been
26 slowest for the two pollutants—ozone and PM2 5—most influenced by meteorology and secondary
27 formation processes.
28 The nationwide trends and those presented for the 10 EPA Regions are based on aggregate statistics
29 across numerous monitoring stations and may not reflect air quality trends at finer scales or for different
30 subsets of monitoring stations. For example, the significant downward trend in ozone in EPA Region 9 is
31 largely influenced by air quality improvements in Los Angeles and other metropolitan areas in southern
32 California. In other urban areas in EPA Region 9, ozone improvements have been more modest or even
33 different directionally.6 Similarly, PM2 5 concentrations have increased over the last 5 years at selected
34 monitoring stations near the border between U.S. and Mexico (the Ozone and PM Concentrations Along
35 U.S./Mexico Border indicator, p. 2-82), even though the national trend for this pollutant is downward.
36 The ROE indicators on criteria pollutants' environmental effects are limited to three issues. First, long-
37 term monitoring data show that wet deposition of acidic sulfates and nitrates decreased between 1989 and
38 2004, consistent with the decreased emissions for sulfur dioxide and nitrogen oxides over roughly the
6 U.S. EPA. 2004. The ozone report: measuring progress through 2003. EPA/454/K-04-001. Research Triangle Park,
NC.
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1 same time frame. As a result of the decreased acid deposition, many surface waters throughout the Upper
2 Midwest, the Adirondack Mountains, and the Northern Appalachian region have begun to recover from
3 past acidification (the Lake and Stream Acidity indicator, p. 2-62). Second, data on ozone injury to forest
4 plants are sufficient for establishing national and regional baseline conditions against which future data
5 can be compared. These baseline conditions show considerable variation in ozone damage across EPA
6 Regions (the Ozone Injury to Forest Plants indicator, p. 2-37). Third, visibility in protected areas (e.g.,
7 National Parks, Wilderness Areas) has remained relatively unchanged between 1992 and 2004 (the
8 Regional Haze indicator, p. 2-50).
9 Overall, for criteria pollutants, the ROE indicators provide fairly complete information on outdoor air
10 quality trends, but limited insights on associated health and environmental effects. As expected, emissions
11 trends are generally consistent with trends observed among corresponding ambient concentrations and,
12 where data are available, effects.
13 Air Toxics and Other Air Pollutants
14 Between 1990 and 2002, nationwide emissions aggregated across 188 air toxics (hazardous air pollutants)
15 decreased (the Air Toxics Emissions indicator, p. 2-70), and decreased emissions were also observed for
16 two air toxics of particular interest: benzene and mercury (the Mercury Emissions indicator, p. 2-68).
17 However, sufficiently complete and consistent monitoring data currently cannot support ROE indicators
18 for ambient concentration of air toxics, with two exceptions. First, ambient air concentrations of benzene
19 at 35 monitoring sites across the nation decreased 61 percent between 1994 and 2004—a decrease
20 reasonably consistent with corresponding emissions reductions. Second, ambient air concentrations of
21 manganese compounds measured at 21 monitoring sites in EPA Region 5 decreased between 2000 and
22 2004, but the period of record evaluated may be too short to consider this decrease an actual air quality
23 trend.
24 Stratospheric Ozone Issues
25 Since 1990, the U.S. phased out most production and import of ozone-depleting substances.
26 Consequently, consumption of ozone-depleting substances in the U.S. decreased during this last decade,7
27 along with globally representative ambient air concentrations of ozone-depleting substances in the lower
28 atmosphere (the Concentrations of Ozone-Depleting Substances indicator, p. 2-76). While such decreases
29 are expected to help restore the stratospheric ozone layer, stratospheric ozone levels over North America
30 actually decreased slightly in the last decade (the Ozone Levels over North America indicator, p. 2-79)
31 due to various factors, including ongoing use of ozone-depleting substances worldwide and the fact that
32 ozone-depleting substances are extremely long-lived in the atmosphere.
7 U.S. EPA. 2005. Ozone depleting substances (ODS) allowance tracking system.
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l Limitations, Gaps, and Challenges8
2 The 23 ROE indicators in this section characterize trends for numerous important outdoor air quality
3 issues, but also have notable limitations. All emissions indicators, for instance, are partly based on
4 estimates. Although these estimates have inherent uncertainties, the emissions inventory data are believed
5 to be of high quality and are periodically updated to remain consistent with the current scientific
6 understanding of emissions from different source categories. The main limitation of the ambient
7 concentration indicators is the monitoring sites' limited spatial coverage. These indicators are composites
8 of air quality measurements taken across the country, but primarily in populated areas and may not totally
9 characterize trends for rural settings. While the national trends for criteria pollutants and benzene are
10 toward improved air quality, ambient concentrations for these pollutants can vary greatly on a local scale.
11 In some areas, such as those experiencing rapid population growth or near newly constructed point
12 sources, ambient air concentrations of selected pollutants are increasing, contrary to the national trends;
13 conversely, ambient air concentration in other parts of the country are decreasing more rapidly than the
14 national trends depict.
15 Though the emissions and ambient concentration indicators are reasonably complete for the criteria
16 pollutants, gaps in nationally representative indicators remain for most air toxics and other air pollutants.
17 However, a large number of these air toxics and other air pollutants are released by a small number of
18 sources nationwide, and these pollutants' emissions and ambient concentrations are more appropriately
19 tracked at the local level, rather than with National Indicators. Another gap in National Indicators is for
20 air toxics and other air pollutants that are ubiquitous in the nation's outdoor air (e.g., mobile source air
21 toxics). Although nationwide trends in air toxics concentrations have been estimated with models,
22 nationally representative ambient air monitoring data on air toxics would provide EPA a more direct
23 measure of important outdoor air quality trends. Many local-scale monitoring networks have tracked
24 trends for some of these pollutants, but nationwide indicators could not be developed for pollutants other
25 than benzene due to limited spatial coverage of monitoring sites, use of differing sampling and analytical
26 methods over the years, inconsistent application of quality assurance and quality control practices, and
27 other factors.
28 ROE indicators for ambient concentrations of some common air toxics are expected to be developed in
29 coming years, based on measurements currently being collected at National Air Toxics Trends Stations.
30 This network of monitoring sites is specifically designed to characterize long-term trends in several air
31 toxics believed to account for the greatest health risks nationwide.9 Additionally, ongoing operation of the
32 Mercury Deposition Network (part of the National Atmospheric Deposition Program) is gathering data to
33 support trends analysis on atmospheric deposition of mercury—an issue of particular significance when
34 evaluating contamination levels in fish and shellfish.
35 National-level exposure and effects indicators can help EPA better characterize nationwide trends in
36 outdoor air quality and their effects, but key challenges complicate efforts to develop these. For example,
37 ambient concentration data do not quantify exposures, because ambient air monitoring equipment
8
While the ROE indicators provide valuable information about trends in outdoor air quality, the indicators are more
limited in their ability to describe trends in associated effects on human health and the environment. As described in
Chapter 1, it is difficult to establish causal relationships between specific stressors and outcomes. In the case of
outdoor air, there are few "effects" indicators with clear causal linkages.
9 U.S. EPA. 2004. National monitoring strategy: air toxics component. Final draft. July.
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1 measures air quality at fixed outdoor locations, while people breathe air in multiple indoor and outdoor
2 settings during a typical day. Actual human exposure to air pollution can be measured through use of
3 personal monitoring devices, which sample the air that people breathe as they move through different
4 microenvironments. Some researchers have used such devices to quantify exposures to specific pollutants
5 in some locations.10 However, conducting such studies on a national scale over an extended time frame
6 would be an extremely resource-intensive task. Consequently, no nationally representative studies
7 currently support ROE indicators that characterize exposure to outdoor air pollutants. Another gap
8 pertaining to effects attributed to outdoor air quality is that the scientific understanding of how all air
9 pollutants, whether acting alone or in combination, can affect human health and the environment is
10 incomplete and continues to evolve.
11 While the indicators document what is currently known about selected outdoor air quality issues, ongoing
12 scientific research continues to broaden the knowledge base on many important topics, ranging from
13 designing innovative emission control technologies to enhancing atmospheric fate and transport modeling
14 to developing metrics that better connect air quality to public health and ecological outcomes.
15
10 Jantunen, M., O. Hanninen, K. Koistinen, and J.H. Hashim. 2002. PM measurements: personal and indoor air
monitoring. Chemosphere 49:993-1007.
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1 2.3 WHAT ARE THE TRENDS IN GREENHOUSE GAS EMISSIONS AND
2 CONCENTRATIONS?
3 2.3.1 Introduction
4 Greenhouse gases, such as carbon dioxide, methane, nitrous oxide, and certain synthetic chemicals, trap
5 some of the Earth's outgoing energy, thus retaining heat in the atmosphere.11 Changes in the radiative
6 balance of the Earth—the balance between energy received from the sun and emitted from Earth—as a
7 result of this heat trapping alter weather patterns and climates at global and regional scales.12 Natural
8 factors, such as variations in the sun's output, volcanic activity, the Earth's orbit, the carbon cycle, and
9 others also affect the radiative balance.13 However, increasing concentrations of greenhouse gases due to
10 human activity are likely affecting various aspects of climate, such as surface air temperature and
11 subsurface ocean temperature; while these and other changes observed over the past few decades are
12 likely mostly due to human activities, scientists cannot rule out the possibility that some significant part
13 of these changes is also a reflection of natural variability.14 Human health, agriculture, water resources,
14 forests, wildlife, and coastal areas all are vulnerable to climate change.15 The purpose of this section is to
15 evaluate long-term trends in air emissions and ambient concentrations of greenhouse gases that are
16 contributing to climate change, but not to evaluate the effects that these emissions and concentrations
17 cause.16
18 Though the focus of this question is on greenhouse gases, related factors can also alter the Earth's
19 climate. Certain radiatively important substances, like black carbon (soot), are technically not greenhouse
20 gases due to their physical state, but they nonetheless affect the flow of energy through the atmosphere.
21 Some of these substances, such as sulfate aerosols, have negative radiative forcings that can lead to
22 cooling effects. Another related factor is albedo (the reflectivity of the Earth's surface), which affects the
23 portions of absorbed and outgoing energy. Natural and human factors can affect albedo on a global scale
24 through changes in large-scale features like the polar ice caps or on a local or regional scale (e.g., by
25 increased amounts of dark paved surfaces that absorb energy). Although this question does not address
26 radiatively important substances that are not greenhouse gases or non-chemical factors like albedo, these
11 National Research Council, Radiative Forcing of Climate Change: Expanding the Concept and Addressing
Uncertainties. March 2005. p. 1,9, vii, and others.
12 Op. cit. p. 11.
13Opcit. p. 13.
14 National Research Council, Climate Change Science: An Analysis of Some Key Questions. 2001. p. 1.
15 NRC op. cit., p. 4 and p. 19-20.
16 In a general sense, climate change is conceptually connected to every other theme in this report. The broadest
discussion of potential effects associated with greenhouse gases in this report is in Section 6.5, which discusses
critical physical and chemical attributes of ecosystems, including ROE indicators that track changes in air
temperature, precipitation, sea-surface temperature, and sea level—all of which affect ecosystems.
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1 influences are also important to understanding the planet's energy balance and the ways human activities
2 may affect that balance.: 7
3 Some greenhouse gases are emitted exclusively from human activities (e.g., synthetic halocarbons).
4 Others occur naturally but are found at elevated levels due to human inputs (e.g., carbon dioxide). The
5 anthropogenic sources result from energy-related activities (e.g., combustion of fossil fuels in the
6 electrical utility and transportation sectors), agriculture, land-use change, waste management and
7 treatment activities, and various industrial processes. Major greenhouse gases and emission sources
8 include:
9 • Carbon dioxide (CO2), which occurs naturally as part of the global carbon cycle, but human
10 activities have increased atmospheric loadings through combustion of fossil fuels and other
11 emissions sources.18 Natural sinks that remove CO2 from the atmosphere (e.g., oceans, plants)
12 help regulate CO2 concentrations, but human activities can disturb these processes (e.g.,
13 deforestation) or enhance them.
14 • Methane (CH4), which comes from many sources, including human activities such as coal
15 mining, natural gas distribution, waste decomposition in landfills, and digestive processes in
16 livestock and agriculture.19 Natural sources include wetlands and termite mounds.
17 • Nitrous oxide (N2O), which is emitted during agricultural and industrial activities, as well as
18 during combustion of solid waste and fossil fuels.
19 • Various synthetic chemicals, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs),
20 sulfur hexafluoride (SF6), and other synthetic gases, which are released as a result of
21 commercial, industrial, or household uses.
22 • Many other gases that are known to trap heat in the atmosphere. Examples include water
23 vapor, which occurs naturally as part of the global water cycle, and ozone, which occurs
24 naturally in the stratosphere and is found in the troposphere largely due to human activities.
25 Each gas has a different ability to absorb heat in the atmosphere, due to differences in its atmospheric
26 half-life and the amount and type of energy that it absorbs. For example, it would take thousands of
27 molecules of CO2 to equal the warming effect of a single molecule of sulfur hexafluoride—the most
28 potent greenhouse gas in terms of ability to absorb heat evaluated by the Intergovernmental Panel on
29 Climate Change (IPCC).20 To facilitate comparisons between gases that have substantially different
17 Detailed information on these related factors may be found in various scientific publications, such as those
prepared by the Intergovernmental Panel on Climate Change, a panel formed by the Worldwide Meteorological
Organization to compile and synthesize the growing body of scientific literature on climate change.
18 U.S. EPA. 2006. Inventory of U.S. greenhouse gas emissions and sinks: 1990-2004. EPA/430/R-06/002.
Washington, DC.
19 National Research Council. 2001. Climate change science: an analysis of some key questions. Washington, DC:
National Academy Press.
20 Intergovernmental Panel on Climate Change. 2001. Climate change 2001: the scientific basis (third assessment
report). Cambridge, UK: Cambridge University Press.
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1 properties, IPCC has developed a set of scaling factors called "global warming potentials" (GWPs), as
2 discussed further in the indicator write-ups.
3 2.3.2 ROE Indicators
4 To characterize trends in greenhouse gases, this chapter presents two indicators—one describing
5 emissions from U.S. sources and the other describing concentrations (Table 2.3.1).
6 The U.S. Greenhouse Gas Emissions indicator covers the period 1990-2003, with data from EPA's
7 Inventory of U.S. Greenhouse Gas Emissions and Sinks. This inventory is a database that tracks both
8 greenhouse gas emissions directly attributable to human activities and greenhouse gas sinks (e.g.,
9 sequestration of carbon in forests). The indicator stratifies emissions into trends for different gases and
10 source categories. Emissions are weighted by "global warming potentials" to facilitate comparison among
11 the gases.
12 The Atmospheric Concentrations of Greenhouse Gases indicator summarizes both direct measurements of
13 ambient air concentrations from the last half-century and observations for earlier time frames based on
14 chemical analyses of air bubbles found in ice core samples. The gases in these bubbles represent the
15 outdoor air that was trapped in ice at the time the ice was formed. Combined, these two measurements
16 provide extensive historical coverage for the atmospheric concentrations of greenhouse gases.
17 Because many greenhouse gases are extremely long-lived in the atmosphere, with some remaining
18 airborne for tens to hundreds of years after being released, these long-lived greenhouse gases become
19 globally mixed in the atmosphere and their concentrations reflect past and recent contributions from
20 emissions sources worldwide. This context is an important backdrop for the two greenhouse gas
21 indicators in this section: increasing atmospheric concentrations of greenhouse gases is a global issue,
22 resulting from emissions from sources in the U.S. combined with emissions from sources in other
23 countries.
24 Table 2.3.1. ROE Indicators of Trends in Greenhouse Gas Emissions and Concentrations
25
NATIONAL INDICATORS
U.S. Greenhouse Gas Emissions
Atmospheric Concentrations of Greenhouse Gases
LOCATION
2.3.2 -p. 2-96
2.3.2 -p. 2-100
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INDICATOR: U.S. Greenhouse Gas Emissions
2 The Earth's climate is determined by the balance between energy received from the sun and emitted back
3 to space from the Earth and its atmosphere. Certain gases in the atmosphere, such as carbon dioxide
4 (CO2), methane (CFL^ and nitrous oxide (N2O), water vapor and others, trap some of the outgoing energy,
5 retaining heat in the Earth's atmosphere. These are the so-called "greenhouse gases" (GHG). The best
6 understood greenhouse gases emitted by human activities are CO2, CH4, N2O, and certain fluorinated
7 compounds.
8 Changes in GHG emissions are influenced by many long-term factors, including population and economic
9 growth, land use, energy prices, technological changes, and inter-annual temperatures. On an annual
10 basis, consumption of fossil fuels, which accounts for most GHG emissions in the U.S., generally
11 fluctuates in response to changes in general economic conditions, energy prices, weather, and the
12 availability of non-fossil alternatives (U.S. EPA, 2005).
13 This indicator uses data and analysis from the Inventory of U.S. Greenhouse Gas Emissions and Sinks
14 (U.S. EPA, 2005), an assessment of the anthropogenic sources and sinks of greenhouse gas emissions for
15 the U.S. and its Territories for the period 1990 through 2003. The inventory constitutes estimates derived
16 from direct measurements, aggregated national statistics, and validated models in most source categories.
17 An extensive discussion of the methods for each source type and gas and the uncertainties inherent in the
18 calculations is available in EPA (2005) and its Annex 7.
19 The indicator is expressed in terms of CO2 equivalents, meaning that emissions of different gases are
20 weighted by their "global warming potential" (GWP). A GWP is a measure of how much a given mass of
21 GHG is estimated to contribute to radiative forcing that contributes to global warming over a selected
22 period of time, compared to the same mass of carbon dioxide, for which the GWP is 1.0. EPA is
23 mandated to use the GWPs documented in the Intergovernmental Panel on Climate Change's Second
24 Assessment Report (IPCC, 1996) and these characterize GWP for a 100 year time horizon—the effect of
25 the gas on radiative forcing over 100 years. Annex 6 of the U.S. GHG Inventory includes extensive
26 information on GWPs and how they relate to emissions estimates (U.S. EPA, 2005).
27 This indicator focuses on the six types of compounds currently covered by agreements under the United
28 Nations Framework Convention on Climate Change. These compounds are CO2, CH4, N2O,
29 hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). This indicator does
30 not include emissions estimates for substances such as chlorofluorocarbons (CFCs), methyl bromide,
31 sulfates, black carbon, and organic carbon. These substances are excluded primarily because either their
32 emissions have not been quantified in the U.S. GHG Inventory or they have different types of effects on
33 climate than those of the six GHG included in the U.S. inventory and, therefore, most cannot be compared
34 directly to the GHG. Combined, these excluded substances may account for a considerable portion of
35 climate change, but their omission cannot be scientifically quantified in comparable terms.
36 This indicator presents emissions data in units of teragrams of CO2 equivalents (Tg CO2 Eq). These units
37 are conventionally used in GHG inventories prepared worldwide. For reference, one teragram (Tg) is
38 equal to one million metric tons.
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1 What the Data Show
2 In 2003, total U.S. greenhouse gas emissions were 6,900 Tg CO2 Eq, up 13 percent from 1990 (Exhibit 2-
3 50). CO2 is the primary greenhouse gas emitted by human activities, representing approximately 85
4 percent of greenhouse gas emissions in 2003. From 1990 to 2003, total emissions of CO2 increased by
5 832 Tg CO2 Eq (17 percent). Methane (CFLO represents the second largest U.S. GHG emission,
6 accounting for 8 percent of net emissions in 2003. Methane emissions declined about 10 percent from
7 1990 to 2003, due largely to reduced emissions from landfills and coal mining operations. The primary
8 sources of methane emissions include decomposition of wastes in landfills, coal mine seepage, natural gas
9 systems, and enteric fermentation in domestic livestock. Nitrous oxide (N2O) constituted about 5 percent
10 of net U.S. GHG emissions in 2003; these emissions declined by about 1 percent from 1990 to 2003. The
1 1 main anthropogenic activities producing N2O are agricultural soil management, fuel combustion in motor
12 vehicles, manure management, nitric acid production, human sewage, and stationary fuel combustion.
13 Emissions of HFCs, PFCs, and SF6 accounted for the remaining 2 percent of GHG emissions in 2003, and
14 the aggregate weighted emissions of this group of gases rose by 46 Tg CO2 Eq (50 percent) since 1990.
15 Despite being emitted in smaller quantities relative to the other principal greenhouse gases, emissions of
16 HFCs, PFCs, and SF6 are important because many of them have extremely high global warming
17 potentials and, in the cases of PFCs and SF6, atmospheric lifetimes of 700 to 50,000 years. The emissions
18 in this indicator are a continuation of the trend of increasing GHG emissions observed over many
19 decades, with total CO2-equivalent emissions increasing by about one fifth since 1970 (U.S. EPA, 2005;
20 RIVM/TNO, 2003). CO2 has constituted a slightly growing portion, while CFU has been a declining
2 1 component of the total .
Exhibit 2-50. Greenhouse gas emissions in the
U.S. by gas, 1990-2003
8,000
7,000
Nitrous oxide
Methane
Carbon dioxide
'90 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05
Year
aTeragrams of carbon dioxide equivalents are the units
conventionally used in greenhouse gas inventories prepared
worldwide. For reference, one teragram equals one million metric
tons.
"MFCs are hydrofluorocarbons, PFCs are perfluorocarbons, and SF6
is sulfur hexafluoride.
Data source: U.S. EPA, 2005
Exhibit 2-51. Greenhouse gas emissions in the
U.S. by industrial sector, 1990-2003
-2,000
\
Industrial processes
Agriculture
Energy
Land use change and forestry (sink)
'90 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05
Year
aleragrams of carbon dioxide equivalents are the units conventionally
used in greenhouse gas inventories prepared worldwide. For
reference, one teragram equals one million metric tons.
Data source: U.S. EPA, 2005
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1 Looking at GHG emissions by source shows that energy use (i.e., fuel combustion and gas leakage) has
2 accounted for about 84 percent of net U.S. emissions since 1990 (Exhibit 2-51). Emissions due to energy
3 use have increased 16 percent between 1990 and 2003. Agriculture is the second largest source of GHG
4 emissions, accounting for 6 percent of the total in 2003. U.S. GHG emissions are partly offset by uptake
5 of carbon and "sequestration" in forests, trees in urban areas, agricultural soils, and landfilled yard
6 trimmings and food scraps. In aggregate, these removals of CO2 from the atmosphere offset about 12
7 percent of U.S. emissions in 2003 (Exhibit 2-51).
8 With one-twentieth of the world's population (U.S. Bureau of the Census, 2006), the U.S. currently emits
9 about one-fifth of global greenhouse gases, CO2, CH4, N2O, HFCs, PFCs, and SF6 (Baumert et al, 2005).
10 Indicator Limitations
11 • This indicator does not yet include emissions of greenhouse gases or other radiatively
12 important substances that are not explicitly covered by the United Nations Framework
13 Convention on Climate Change and its subsidiary protocol. Thus, it excludes such gases as
14 those controlled by the Montreal Protocol and its Amendments, including CFCs and
15 hydrochlorofluorocarbons (HCFCs). Although the U.S. reports the emissions of these
16 substances as part of the U.S. GHG inventory (see Annex 6.2 of the U.S. GHG Inventory),
17 the origin of the estimates is fundamentally different from those of the other GHG and
18 therefore cannot be compared directly with the other emissions discussed in this indicator.
19 • This indicator does not include aerosols and other emissions that do affect radiative forcing
20 and that are not well-mixed in the atmosphere, such as sulfate, ammonia, black carbon and
21 organic carbon. Emissions of these compounds are highly uncertain and have qualitatively
22 different effects than the six types of emissions in this indicator.
23 • This indicator does not include emissions of other compounds such as CO, NOX, nonmethane
24 volatile organic compounds (VOCs), and substances that deplete the stratospheric ozone
25 layer, which indirectly affect the Earth's radiative balance, for example, by altering
26 greenhouse gas concentrations, changing the reflectivity of clouds, or changing the
27 distribution of heat fluxes.
28 • The U.S. GHG Inventory does not account for "natural" emissions of greenhouse gases, such
29 as from wetlands, tundra soils, termites, and volcanoes. These excluded sources are discussed
30 in Annex 5 of the U.S. GHG Inventory (U.S. EPA, 2005). The U.S. GHG Inventory does
31 include, in its Land Use and Land Use Change and Forestry categories, emissions from
32 changes in the forest inventory due to fires, harvesting, and other activities, and from
33 agricultural soils.
34 Data Sources
35 The data used for this indicator were published in EPA's inventory of greenhouse gas emissions and sinks
36 for years 1990-2003 (U.S. EPA, 2005). Specifically, emissions by GHG shown in Exhibit 2-50 are taken
37 from Table ES-2 of that reference, and emissions by industrial sector are taken from Table ES-4.
38 References
39 Baumert, K., T. Herzog, and J. Pershing. 2005. Navigating the numbers: greenhouse gas data and
40 international climate policy. Washington DC: World Resources Institute.
41
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1 IPCC (Intergovenmental Panel on Climate Change). 1996. Climate change 1995: the science of climate
2 change. Cambridge, United Kingdom: Cambridge University Press.
3 RIVM/TNO. 2003. Emission database for global atmospheric research. Version 3.2. 2003. (Olivier,
4 J.G.J., and J.J.M. Berdowski. 2001. Global emission sources and sinks.)
5 U.S. Bureau of the Census. 2006. World POPClock; USPOPClock.
6
7 U.S. EPA. 2005. Inventory of U.S. greenhouse gas emissions and sinks: 1990-2003.
8
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NDICATOR: Atmospheric Concentrations of Greenhouse Gas
2 The Earth's temperature depends mainly on the amount of energy received from the sun, the portion
3 reflected back into space, and the extent to which the atmosphere retains heat. Natural forces (e.g.,
4 volcanoes, changes in the Earth's orbit) and human activities (e.g., emissions of so-called "greenhouse
5 gases," land use change) affect the amount of energy held in the Earth-atmosphere system and therefore
6 affect the Earth's climate. Human activities in all countries have altered the chemical composition of the
7 atmosphere by the emissions and accumulation in the atmosphere of greenhouse gases. The primary gases
8 that retain heat in the atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and certain
9 manufactured gases such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and sulfur
10 hexafluoride (SF6).
11 Once emitted, gases remain in the atmosphere for varying amounts of time. Very "short-lived"
12 compounds, such as particulate matter, may remain airborne on average for only hours or days. Methane
13 also has a relatively short average lifetime, though much longer than PM, remaining in the atmosphere for
14 roughly 12 years. The half-life of CO2 emissions is roughly 100 years (5 to 200 years: IPCC, 2001), but
15 about a quarter of emissions today will still be in the atmosphere after hundreds of years and about one-
16 tenth for hundreds of thousands of years (Archer, 2005; Archer et al., 1998). Finally, many of the
17 synthetic gases such as halocarbons are extremely long-lived, remaining in the atmospheric for hundreds
18 or even tens of thousands of years. When emissions—from the U.S. (the U.S. Greenhouse Gas Emissions
19 indicator, p. 2-96) as well as other countries—remain in the atmosphere over long periods, they
20 accumulate and are measured as atmospheric concentrations. U.S. GHG emissions from 1890 to 2000 are
21 estimated to have contributed about one-fifth of the increase in global GHG concentrations (den Elzen et
22 al., 2005).
23 This indicator shows trends in the accumulation of the following principal greenhouse gases in the
24 atmosphere: CO2, CH4, N2O, and selected halocarbons. Recent data are from global networks that monitor
25 the concentrations of these gases in the atmosphere. Geologic data result from gas measurements made of
26 air trapped in ice cores at the time the ice was formed. Because the gases shown in this indicator remain
27 in the atmosphere for long periods, they are well-mixed, so that measurements at individual locations are
28 globally representative. This indicator summarizes greenhouse gas concentration measurements reported
29 in a collection of studies published in the peer-reviewed literature. In order to provide the most extensive
30 temporal coverage, this indicator aggregates comparable, high quality data from individual studies that
31 each focused on different time frames. None of the data in this indicator is based on modeled
32 concentrations.
33 What the Data Show
34 Exhibits 2-52 through 2-54 show the evolution of concentrations of three principal greenhouse gases in
35 the atmosphere over three intervals: geologic time (hundreds of thousands of years), the past 11,000
36 years, and in recent decades. The exhibits represent data sets covering a wide range of latitudes, showing
37 some latitudinal differences in concentrations, but also showing a high level of consistency—indicating
38 that the gases are well-mixed and that the sampling can be considered spatially representative. The graphs
39 show patterns of large cycles of concentrations over geologic time, but also increases in concentrations
40 since the Industrial Revolution that exceed concentrations over the past hundreds of thousands of years.
41 The concentration of CO2 has varied considerably over geological time (Exhibit 2-52). Over the past
42 420,000 years, CO2 concentrations have cycled over several thousand year periods from highs around
43 285-300 ppm to lows around 180-185 ppm. From at least 900 A.D. to 1800 A.D., CO2 concentrations
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Exhibit 2-52. Global atmospheric concentrations of carbon dioxide (COa) over geological time and in
recent years
400
350
E" 300
^ 250
g
1 200
S
I
CM
o
A. 415,155 BC to 337 BC
B. 8947 BC to 1975 AD
C. 1959 AD to 2004 AD
150
0 100
50
-450,000 -300,000 -150,000
0 -10,000 -8000 -6000 -4000 -2000 0 2000 1955 1965 1975 1985 1995 2005
Year (negative values = BC)
Trend lines and data sources:
415,155 BC to 337 BC 8947 BC to 1975 AD
- Vostok Station, Law Dome, East Antarctica
Antarctica (Barnola 75-year smoothed
et al., 2003) (Etheridge et al., 1998)
- Siple Station, West
Antarctica (Neftel era/..
7994;
Antarctica (Petit era/.,
2001)
1959 AD to 2004 AD
Barrow, Alaska (Steele
etal.,2002)
Cape Matatula, American
Samoa (Thoning era/.,
2000;
- South Pole, Antarctica
(Thoning et al., 2000)
Mauna Loa, Hawaii (Keeling
etal.,2005)
Lampedusa Island, Italy
(Chamardetal.,2001)
Shetland Islands, Scotland
(Steele etal.,2002)
Cape Grim, Australia (Steele
etal.,2002)
I stayed relatively constant at about 270-290 ppm (panel B). Over the past 150 years, CO2 concentrations
2 have increased by 3 1 percent; from 1958 to 2002, they have increased by about 18 percent (plus or minus
3 1 percent) to 374 ppm (panels B and C).
4 Methane (CH4) concentrations also cycled widely over the past 420,000 years but peaks remained below
5 800 ppb until after 1800 A.D. (Exhibit 2-53). Essentially no increase occurred from 1000 A.D. to 1730
6 A.D. (panel B). It then took approximately 175 years (c. 1905) to add 200 ppb to atmospheric CUt
7 concentrations, 40 years (c. 1945) to add the next 200 ppb, 20 years to add the next 200 ppb (c. 1965), and
8 10 years (c. 1975) to add the next 200 ppb (panels B and C). The rates of methane increase began to slow
9 by the late 1970s, with less than 200 ppb added to atmospheric concentrations between 1978 and the
10 present (panel C). Overall, global methane concentrations more than doubled in the past 150 years. The
1 1 most recent data show that there is a significant difference in methane concentrations across latitudes,
12 with a pattern of peak concentrations in the most northern latitudes decreasing toward the southern
13 latitudes, which suggests net sources of methane in northern latitudes. Yet, despite the latitudinal
14 differences in concentrations, the pattern over the past two centuries shows a common trend in all
15 locations.
16
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Exhibit 2-53. Global atmospheric concentrations of methane (ChU) over geological time and in recent years
2,000
S 1,500
A. 415,168 BC to 347 BC
B. 8945 BC101980 AD
C. 1985 AD to 2001 AD
I
I
1,000
500
-500,000 -400,000 -300,000 -200,000 -100,000 0 -10,000 -8000 -6000 -4000 -2000 0 2000 1985
1990
1995
2000
2005
Year (negative values = BC)
Trend lines and data sources:
415,168 BC to 347 BC
- Vostok Antarctica ice core (Petit et a/.,
2001)
Greenland GRIP ice core (Blunieretal.,
2001)
- Greenland GISP2 ice core (Blunieretal.,
2001)
Antarctica Byrd Station ice core
(Blunieretal., 2001)
8945 BC to 1980 AD
1985 AD to 2001 AD
Law Dome, Antarctica (Etheridge etal.,
2002)
Various Greenland locations
(Etheridge etal., 2002)
- Greenland Site J (Hashida etal., 2005)
Antarctica (Petitetal., 2001)
Cape Grim, Australia (Steele etal.,
2002)
Shetland Islands, Scotland (Steele
etal., 2002)
Mauna Loa, Hawaii (Steele etal.,
2002)
J
1 Nitrous oxide (N2O) concentrations (Exhibit 2-54) vacillated widely through geologic time, with ice
2 sample measurements ranging from as low as 180 ppb to above 280 ppb. Despite considerable inter-
3 decadal variability, N2O stayed mostly below 280 ppb from 1756 A.D. until the 1920s (panel B), from
4 which point levels began to rise rapidly to approximately 318 ppb in 2004 (panels B and C), the highest
5 level ever recorded.
6 Concentrations of the halocarbons (or gases that contain the halogens chlorine, fluorine, bromine, or
7 iodine) were essentially zero a few decades ago, but have increased rapidly as they were incorporated into
8 industrial products and processes (Exhibit 2-55). Concentrations of hydrochlorofluorocarbons HCFC-
9 141b and HCFC-142b increased sharply through 2005 (panel A), but are expected to gradually stabilize
10 over this decade as they are phased out in industrialized countries as part of the Montreal Protocol on
11 Substances the Deplete the Ozone Layer. The concentration of HFC-23, which is a by-product of HCFC-
12 22 production, has increased more than five-fold between 1978 and 2005 (panel B). HFCs that are not
13 controlled by the Protocol (because they do not contribute to stratospheric ozone losses) mostly continue
14 to increase because of their widespread use as substitutes for the Montreal Protocol gases.
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Exhibit 2-54. Global atmospheric concentrations of nitrous oxide
recent years
over geological time and In
A. 104,299 BC to 1873 AD
B. 8945 BC to 1976 AD
C. 1977 AD to 2004 AD
350
325
S 300
Q.
Q.
i" 275
1
i 250
s
I 225
I1 200
-125,000-100,000-75,000-50,000-25,000 0 25,000-10,000-8000 -6000 -4000 -2000 0 2000 1975
1985 1990 1995 2000 2005
Year (negative values = BC)
Trend lines and data sources:
104,299 BC to 1873 AD
- GISP II Greenland (Sowersetal,
2003)
Taylor Dome (Sowers et al., 2003)
8945 BC to 1976 AD
1977 AD to 2004 AD
Dome C, Antarctica (Fluckigeretal.,
2002)
Antarctica (Machidaetal., 1995)
Antarctica (Battle et al., 1996)
Barrow, Alaska (Elkins etal., 2005)
- Cape Grim, Australia (Elkins etal.,
2005)
Mauna Loa, Hawaii (Elkins etal., 2005)
South Pole, USA station (Elkins
etal., 2005)
1 Indicator Limitations
2
3
4
5
6
1
8
9
10
11
12
13
14
15
16
17
Water vapor is not tracked in this indicator as it is generally accepted that human activities
have not increased the concentration of water vapor in the atmosphere.
Some radiatively important atmospheric constituents that are substantially affected by human
activities such as tropospheric ozone, black carbon, aerosols, and sulfates are not included in
this indicator because of their spatial and temporal variability and the inadequacy of available
data to characterize long-term averages or trends.
Concentration data are not available for all the halogenated compounds that are potentially
important greenhouse gases. For instance, global concentration data are not sufficient yet to
track trends in concentrations of SF6 and PFCs.
Ice core measurements are not taken in real time, which introduces some error into the date of
the sample. Dating accuracy for the ice cores ranged up to +20 years (often less), depending
on the method used and the time period of the sample. Diffusion of gases from the samples,
which would tend to reduce the measured values, may also add a small amount of
uncertainty. More information on the accuracy of measurements of ice samples and other
measurement methods can be found at:
http://cdiac.esd.ornl.gov/bv new/bvsubiec.html#atmospheric.
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Exhibit 2-55. Global atmospheric concentrations
of selected halocarbons, 1978-2005"
A. Concentrations of selected hydrochlorofluorocarbons
1975 1980 1985 1990 1995 2000 2005
Year
B. Concentrations of selected hydrofluorocarbons
1975 1980 1985 1990 1995 2000 2005
Year
'Trends are presented for hydrochloro-
fluorocarbons (HCFCs) and hydrofluoro-
carbons (MFCs) with sufficient data to
support long-term trend analysis.
HCFC-22
HCFC-142b
HCFC-1Z4
HCFC-141b
Data source: IPCC, 2001, and Australia
Commonwealth Scientific and Industrial
Research Organisation (CSIRO), Marine
and Atmospheric Research, 2006
HFC-23
HFC-152a
HFC-125
HFC-134a
Data Sources
The data in this indicator come from multiple
sources. Summary global atmospheric concentration
data for CO2 (Exhibit 2-52), CH4 (Exhibit 2-53), and
N2O (Exhibit 2-54) were provided by EPA's Office
of Atmospheric Programs, based on greenhouse gas
concentration measurements reported in a collection
of studies published in the peer-reviewed literature.
Citations for these studies and links to the
corresponding underlying data can be found online
at:
http://www.epa.gov/climatechange/science/recentac
majorghg.html.
Summary global atmospheric concentration data for
selected halocarbons (Exhibit 2-55) were provided
by the Australia Commonwealth Scientific and
Industrial Research Organisation (CSIRO). The
1975-2001 data in this exhibit are taken from
IPCC's third assessment report on climate change
(IPCC, 2001). The 2002-2005 data in this exhibit
were not publicly available at the time this report
went to press, but they will be published in IPCC's
upcoming fourth assessment report on climate
change.
References
Exhibits 2-52, 2-53, and 2-54 refer to 16 data
sources. Complete citations for these references and
links to the corresponding underlying data can be
found online at:
http://www.epa.gov/climatechange/science/recentac
maiorghg.html.
Archer, D., and A. Ganopolski. 2005. A movable
trigger: fossil fuel CO2 and the onset of the next
glaciation. Geochem Geophys Geosys 6(Q05003)
37 Archer, D., H. Kheshgi, and E. Maier-Reimer. 1998. Dynamics of fossil fuel neutralization by Marine
38 CaCO3. Global Biogeochem Cycles 12:259-276.
39
40 den Elzen, M., J. Fuglestvedt, N. Hohne, C. Trudinger, J. Lowe, B. Matthewso, B. Romstadv, C. Pires de
41 Campos, and N. Andronova. 2005. Analysing countries' contribution to climate change: scientific and
42 policy-related choices. Env Sci percent Policy June 05.
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1 IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: the scientific basis
2 (third assessment report). Cambridge, UK: Cambridge University Press.
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1 2.3.3 Discussion
2 What These Indicators Say About Trends in Greenhouse Gas Emissions
3 and Concentrations
4 The nation's estimated combined emissions of several greenhouse gases that are directly attributable to
5 human activity have increased 13 percent between 1990 and 2003 (the U.S. Greenhouse Gas Emissions
6 indicator, p. 2-96). Emissions sources occur from several sectors of the U.S. economy, with the highest
7 contribution—and the greatest recent growth—attributed to energy use, which primarily includes
8 electricity generation and transportation sources. This indicator also compares contributions of different
9 greenhouse gases by normalizing for each gas's ability to affect the Earth's energy balance. The results
10 show that CO2 makes up the bulk of the nation's anthropogenic greenhouse gas emissions. Both
11 observations demonstrate that fossil fuel combustion is clearly the country's major source of
12 anthropogenic greenhouse gas emissions.
13 Data on atmospheric concentrations of greenhouse gases have extraordinary temporal coverage (the
14 Greenhouse Gas Concentrations indicator, p. 2-100). For CO2, methane, and N2O, concentration data span
15 several hundred thousand years; and for selected halocarbons, concentration data span virtually the entire
16 time frame that these synthetic gases were widely used. Thus, these concentration data provide an
17 excellent basis for answering the question regarding trends in greenhouse gas concentrations. The
18 historical data for CO2, methane, and N2O show considerable temporal variability in these gases'
19 concentrations; however, concentrations observed in the past 50 years are higher than those over the
20 entire period of record evaluated—even when considering natural fluctuations. In short, the historical
21 context provided by ice cores shows that present concentrations of these three greenhouse gases are
22 unprecedented over the last 420,000 years, and strongly suggest that the recently increasing levels mostly
23 reflect the influence of human activity. For the various halocarbons considered, concentrations have
24 increased between 1980 and 2000, with some increases spanning more than two orders of magnitude, but
25 the rate at which these concentrations is increasing has slowed in recent years.
26 Taken together, the well-documented long-term trends in concentrations of greenhouse gases, along with
27 corresponding increases in emissions from anthropogenic sources, show that human activity is causing
28 increased concentrations of greenhouse gases in the Earth's atmosphere—a finding echoed in many
29 prominent reviews on the science of climate change.21'22
30 Limitations, Gaps, and Challenges
31 Although they provide extensive insights into greenhouse gas emissions and concentrations, the two
32 greenhouse gas indicators have limitations and gaps that should be acknowledged. The emissions trends,
33 for instance, are based largely on estimates, which have uncertainties inherent in the engineering
34 calculations and estimation methodologies developed for the U.S. greenhouse gas emissions inventory.
35 Uncertainty of the magnitude of the emissions vary among the gases and sources, though estimated
36 emissions from some of the largest sources (e.g., CO2 emissions from fossil fuel combustion) are
21 National Research Council. 2001. Climate change science: an analysis of some key questions. Washington, DC:
National Academy Press.
22 Intergovernmental Panel on Climate Change. 2001. Climate change 2001: the scientific basis (third assessment
report). Cambridge, United Kingdom: Cambridge University Press.
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1 considered highly accurate.23 One gap in the emissions indicator is that EPA's GHG inventory does not
2 track every greenhouse gas or every emissions source. Examples of greenhouse gases not included in the
3 inventory are ozone and selected chlorofluorcarbons. The most notable sources not tracked in the
4 inventory are natural sources, such as CIL, from wetlands, CO2 and CH4 from thawing permafrost, and
5 multiple emissions from volcanoes. Although worldwide emissions of greenhouse gases from natural
6 sources actually far outweigh inputs attributed to human origin,24 the incremental increases of
7 anthropogenic emissions are environmentally noteworthy because they upset the balance of natural
8 sources and sinks of greenhouse gases. Though not necessarily a limitation or a gap, it is important to
9 note that EPA's Greenhouse Gas Inventory, by design, tracks only this nation's anthropogenic emissions
10 of greenhouse gases. For perspective on how the nation's emissions compare to those from other
11 countries, recent data estimate that the U.S. emits approximately 20 percent of the total worldwide
12 amounts of selected greenhouse gases.25 Having national emissions indicators on a more complete set of
13 greenhouse gases and emissions sources would further improve EPA's ability to track pressures that
14 affect climate change.
15 The Greenhouse Gas Concentrations indicator (p. 2-100) tracks trends in measured airborne levels of
16 greenhouse gases regardless of the anthropogenic or natural sources that released them, which helps
17 account for some of the inherent limitations and uncertainties in the emissions indicator. However, the
18 concentration data have limitations and gaps of their own. Historical concentrations from ice core samples
19 are not measured in real time, which introduces some minor uncertainty into the data set; consistency
20 among measurements made by multiple laboratories at different locations suggests this uncertainty is
21 relatively low.26 A gap in the concentration data, as with the emissions data, is that not all greenhouse
22 gases have been monitored. Long-term trend data for ozone, for instance, are currently not available.
23 Measuring globally representative trends in tropospheric ozone concentrations presents technical
24 challenges, because ozone is a short-lived gas (which does not lend well to ice core measurements) with
25 concentrations that exhibit tremendous spatial variations (which would require extensive monitoring to
26 characterize worldwide trends). Another gap is the lack of ROE indicators for radiatively important
27 substances, such as soot and aerosols. Though these substances technically are not greenhouse gases,
28 tracking trends in these substances' concentrations is important due to their ability to alter the Earth's
29 energy balance.
30
23 U.S. EPA. 2003. Inventory of U.S. greenhouse gas emissions and sinks: 1990-2003. EPA/430/R-05/003.
Washington, DC.
24 U.S. EPA. 2000. Global warming and our changing climate: answers to frequently asked questions. EPA/430/F-
00/011. Washington, DC.
25 denElzen, M, J. Fuglestvedt, N. Hohne, C. Trudinger, J. Lowe, B. Matthews, B. Romstad, C. Pires de Campos,
and N. Andronova. 2005. Analysing countries' contribution to climate change: scientific and policy-related choices.
Env. Sci. Policy 8(6):614-636.
26 Barnola, J., D. Raynaud, C. Lorius, and N.I. Barkov. 2003. Historical CO2 record from the Vostok ice core. In:
Trends: a compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy.
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1 2.4 WHAT ARE THE TRENDS IN INDOOR AIR QUALITY AND THEIR EFFECTS
2 ON HUMAN HEALTH?
3 2.4.1 Introduction
4 Indoor air quality refers to the quality of the air in a home, school, office, or other building environment.
5 Most pollutants affecting indoor air quality come from sources inside buildings, although some originate
6 outdoors. Typical pollutants of concern include combustion products such as carbon monoxide,
7 particulate matter, and environmental tobacco smoke; substances of natural origin such as radon;
8 biological agents such as molds; pesticides; lead; asbestos; ozone (from some air cleaners); and various
9 volatile organic compounds (VOCs) from a variety of products and materials. Indoor concentrations of
10 some pollutants have increased in recent decades due to such factors as energy-efficient building
11 construction and increased use of synthetic building materials, furnishings, personal care products,
12 pesticides, and household cleaners.
13 The potential impact of indoor air quality on human health nationally is considerable, for several reasons.
14 Americans, on average, spend approximately 90 percent of their time indoors,27 where the concentrations
15 of some pollutants are often 2 to 5 times higher than typical outdoor concentrations.28 Moreover, people
16 who are often most susceptible to the adverse effects of pollution (e.g., the very young, older adults, and
17 people with cardiovascular or respiratory disease) tend to spend even more time indoors.29 Health effects
18 that have been associated with indoor air pollutants include irritation of the eyes, nose, and throat;
19 headaches, dizziness, and fatigue; respiratory diseases; heart disease; and cancer.
20 Indoor air pollutants originate from many sources. These sources can be classified into two general
21 categories:
22 • Indoor sources (sources within buildings themselves). Combustion sources in indoor
23 settings, including tobacco, heating and cooking appliances, and fireplaces, can release
24 harmful combustion by-products such as carbon monoxide and particulate matter directly into
25 the indoor environment. Cleaning supplies, paints, insecticides, and other commonly used
26 products introduce many different chemicals, including volatile organic compounds, directly
27 into the indoor air. Building materials are also potential sources, whether through degrading
28 materials (e.g., asbestos fibers released from building insulation) or from new materials (e.g.,
29 chemical off-gassing from pressed wood products). Other substances in indoor air are of
30 natural origin, such as mold and pet dander.
27 U.S. EPA. 1989. Report to Congress on indoor air quality: volume 2. EPA/400/1-89/001C. Washington, DC.
28 U.S. EPA. 1987. The total exposure assessment methodology (TEAM) study: summary and analysis. EPA/600/6-
87/002a. Washington, DC.
29 U.S. EPA. 1997. Exposure factors handbook: volume 3—activity factors. EPA/600/P-95/002Fa. Washington, DC.
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1 • Outdoor sources. Outdoor air pollutants can enter buildings through open doors, open
2 windows, ventilation systems, and cracks in structures. Some pollutants come indoors
3 through building foundations. For instance, radon forms in the ground as naturally occurring
4 uranium in rocks and soils decays. The radon can then enter buildings through cracks or gaps
5 in structures. In areas with contaminated ground water or soils, volatile chemicals can enter
6 buildings through this same process. Finally, when people enter buildings, they can
7 inadvertently bring in soils and dusts on their shoes and clothing from the outdoors, along
8 with pollutants that adhere to those particles.
9 In addition to pollutant sources, the air exchange rate with the outdoors is an important factor in
10 determining indoor air pollutant concentrations. The air exchange rate is affected by the design,
11 construction, and operating parameters of buildings and is ultimately a function of infiltration (air that
12 flows into structures through openings, joints, and cracks in walls, floors, and ceilings and around
13 windows and doors), natural ventilation (air that flows through opened windows and doors), and
14 mechanical ventilation (air that is forced indoors or vented outdoors by ventilation devices, such as fans
15 or air handling systems). Outdoor climate and weather conditions combined with occupant behavior can
16 also affect indoor air quality. Weather conditions influence whether building occupants keep windows
17 open or closed, or whether occupants operate air conditioners, humidifiers, or heaters, all of which can
18 impact indoor air quality. Weather also has a large effect on infiltration. Certain climatic conditions can
19 increase the potential for indoor moisture and mold growth if not controlled by adequate ventilation or air
20 conditioning.
21 The link between some common indoor air pollutants and health effects is very well established. Radon is
22 a known human carcinogen and is the second leading cause of lung cancer.30'31 Carbon monoxide is toxic
23 and short-term exposure to elevated carbon monoxide levels in indoor settings can be lethal.32 Episodes of
24 "Legionnaires' Disease," a form of pneumonia caused by exposure to the Legionella bacterium, have
25 been associated with buildings with poorly maintained air conditioning or heating systems.33'34 In
26 addition, numerous indoor air pollutants—dust mites, mold, pet dander, environmental tobacco smoke,
27 cockroach allergens, and others—are "asthma triggers," meaning that some asthmatics might experience
28 asthma attacks following exposure.35
30 U.S. EPA. 2003. EPA assessment of risks from radon in homes. EPA/402/R-03/003. Washington, DC.
31 National Research Council. 1999. Health effects of exposure to indoor radon: biological effects of ionizing
radiation (BEIR), report VI. Washington, DC: National Academy Press.
32 Raub, J.A., M. Mathieu-Nolf, N.B. Hampson, S.R. Thorn. 2000. Carbon monoxide poisoning—a public health
perspective. Toxicology 145:1-14.
33 Allan, T., et al. 2001. Outbreak of legionnaires' disease among automotive plant workers—Ohio, 2001. MMWR
50(18):357-359.
34 Fields, B.S., R.F. Benson, and R.E. Besser. 2002. Legionella and legionnaires' disease: 25 years of investigation.
Clin. Microbiol. Rev. 15(3):506-526.
35 U.S. Institute of Medicine. 2000. Clearing the air: asthma and indoor air exposures. Washington, DC: National
Academy Press.
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1 While these and other adverse health effects have been attributed to specific pollutants, the scientific
2 understanding of some indoor air quality issues continues to evolve. One example is "sick building
3 syndrome," which occurs when building occupants experience similar symptoms after entering a
4 particular building, with symptoms diminishing or disappearing after leaving the building, and these
5 symptoms are increasingly being attributed to a variety of building indoor air attributes.
6 Researchers also have been investigating the relationship between indoor air quality and important issues
7 not necessarily related to health, such as student performance in the classroom and productivity in
8 occupational settings.36 Another evolving area is research in "green building" design, construction,
9 operation, and maintenance that achieves energy efficiency and enhances indoor air quality.
10 2.4.2 ROE Indicators
11 Two National Indicators that fully meet the indicator criteria are discussed in this section. These
12 indicators address two specific issues and do not cover the wide range of issues associated with indoor air
13 quality. The two indicators focus on radon and environmental tobacco smoke. The indicator on radon
14 levels in homes is based on EPA's 1992 National Residential Radon Survey, 2000 U.S. Census data, and
15 production and sales statistics for radon mitigation systems. Environmental tobacco smoke is addressed
16 using biomarker data for cotinine, a metabolite linked exclusively to chemicals found in tobacco smoke.
17 The Centers for Disease Control and Prevention (CDC) have reported these biomarker data in multiple
18 releases of its National Health and Nutrition Examination Survey.
19 Table 2.4.1. ROE Indicators of Trends in Indoor Air Quality and Their Effects on Human Health
20
NATIONAL INDICATORS
U.S. Homes Above EPA's Radon Action Level
Blood Cotinine Level
LOCATION
2.4.2 -p. 2-111
2.4.2 -p. 2-114
36 U.S. EPA. 2003. Indoor air quality and student performance. EPA/402/K-03/006. Washington, DC.
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INDICATOR: U.S. Homes Above EPA'
Action Level
2 Radon is a radioactive gas. It comes from the decay of uranium that is naturally occurring and commonly
3 present in rock and soils. It typically moves up through the ground to the air above and into a home
4 through pathways in ground contact floors and walls. Picocuries per liter of air (pCi/L) is the unit of
5 measure for radon in air (the metric equivalent is becquerels per cubic meter of air, or Bq/m3).
6 Each year radon is associated with an estimated 21,100 lung cancer deaths in the U.S. with smokers at an
7 increased risk; radon is the second leading cause of lung cancer after smoking, and 14.4 percent of lung
8 cancer deaths in the U.S. are believed to be radon-related (U.S. EPA, 2003). To reduce the risk of lung
9 cancer, EPA has set a recommended "action level" of 4 pCi/L for homes. At that level, it is cost-effective
10 for occupants to reduce their exposure by implementing preventive measures in their homes.
11 This indicator presents: (1) the number of U.S. homes estimated to be at or above the EPA recommended
12 radon action level of 4 pCi/L; and (2) the number of homes with an operating radon mitigation system.
13 The gap between the homes in (1) and in (2) is the number of homes that have not yet been mitigated
14 (generally, homes are only mitigated if the EPA recommended radon action level of 4 pCi/L or more is
15 measured). The data for this indicator were extracted from the National Residential Radon Survey (U.S.
16 EPA, 1992a) which estimated radon levels in the U.S. housing stock. The number of homes at or above 4
17 pCi/L was estimated by applying: (1) the results of the National Residential Radon Survey (U.S. EPA,
18 1992a) to (2) 2000 U.S. Census data on the number of U.S. households. The 1992 National Residential
19 Radon Survey was based on the housing stock that would be covered by EPA's radon testing policy (i.e.,
20 homes that should test). This included only homes intended for regular (year-round) use but covers single-
21 family homes, mobile homes, multi-unit and group quarters (U.S. EPA, 1992b). The 1992 residential
22 survey estimated that about one in fifteen homes in EPA's "should test" category would have a radon
23 level of 4 pCi/L or more. The measure of the number of homes with an operating mitigation system
24 (ROMS) was developed from radon vent fan (RVF) sales data provided voluntarily by fan manufacturers.
25 What the Data Show
26 There was a 272 percent increase in the number of homes with an operating mitigation system from 1990
27 to 2004, going from 155,000 to 577,000 homes over 15 years; but during the same period, there has been
28 a 26 percent increase in the estimated number of homes with radon levels greater than 4 pCi/L, from
29 about 5 million to 6.3 million (Exhibit 2-56, panel A). Panel B of Exhibit 2-56 shows radon potential in
30 homes at the county level based on indoor radon measurements, geology, aerial radioactivity, soil
31 permeability, and foundation type. Zone 1 is the highest radon potential area, followed by Zone 2
32 (medium), and Zone 3 (low).
33 It has been reported anecdotally that radon vent fans and mitigation systems are also being used to control
34 for soil gases/intrusion in homes in the vicinity of RCRA, Superfund, UST/AST and similar sites as an
35 element of corrective action plans. While fans used in this way may provide a radon reduction benefit,
36 they could be considered a subtraction from the number of homes with an operating mitigation system,
37 thus reducing slightly the slope of the trend line.
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Exhibit 2-56. Homes above EPAs radon action
level and homes with operating mitigation
systems in the U.S., 1990-2004
Homes with estimated radon
indoor air concentrations
greater than 4 pCi/L
Homes with radon
mitigation systems
'96 '98 '00 '02 '04 '06
Year
B. EPA map of radon zones
Guam-
Preliminary
zone designation
i Zone 1: Counties with predicted average indoor radon
screening levels greater than 4 pCi/L
] Zone 2: Counties with predicted average indoor radon
screening levels from 2 to 4 pCi/L
D Zone 3: Counties with predicted average indoor radon
screening levels less than 2 pCi/L
Data source: Number of homes above 4 pCi/L provided by U.S.
EPA, W92b. updated with 2000 U.S. Census data. Mitigation
system data provided by U.S. EPA. unpublished industry data on
mitigation system sales, 2005. Radon map provided by U.S.
EPA. 1999.
Indicator Limitations
• The indicator presumes that radon
vent fans are used for their intended
purpose; the available information
supports this premise.
• Homes with an operating mitigation
system are presumed to have a vent
fan with an average useful life of 10
years. Each year the total of ROMS is
adjusted to reflect new additions and
subtractions (i.e., fans added 11 years
earlier).
• The number of homes with radon
levels at or greater than 4 pCi/L is an
estimate based on one year of
measurement data extrapolated for
subsequent years based on population
data, rather than on continuing
measurements.
• This indicator does not track the
number of homes designed and built
with radon-resistant new construction
features, which can prevent radon
from entering homes. Thus, more
people are likely being protected from
elevated indoor air exposures to radon
than suggested by the trends in radon
mitigation systems alone.
Data Sources
Summary data in this indicator were provided by
EPA's Office of Radiation and Indoor Air, based
on two types of information. The number of homes
with estimated radon indoor air concentrations
above EPA's radon action level was derived from
the National Residential Radon Survey (EPA,
1992a) and U.S. Census data; and the number of
homes with radon mitigation systems was
developed from unpublished sales data provided
by radon vent fan manufacturers.
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1 References
2 U.S. EPA. 2003. EPA assessment of risks from radon in homes. EPA/402/R-03/003. Washington, DC.
3
4 U.S. EPA. 1992a. National residential radon survey: summary report. EPA/402/R-92/011. Washington,
5 DC. October.
6 U.S. EPA. 1992b. Technical support document. EPA/400/R-92/011.
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INDICATOR: Blood Cotinine Level
2 Environmental tobacco smoke (ETS) contains a mixture of toxic chemicals, including known human
3 carcinogens. Persistent exposure to ETS is associated with numerous health related disorders or
4 symptoms, such as coughing, chest discomfort, reduced lung function, acute and chronic coronary heart
5 disease, and lung cancer (IARC, 2004; NTP, 2002; U.S. EPA, 1992; CDC, 2005). Children are at
6 particular risk from exposure to ETS, which may exacerbate existing asthma among susceptible children
7 and also greatly increase the risk for lower respiratory tract illness, such as bronchitis and pneumonia,
8 among younger children (CDC, 2005). Younger children appear to be more susceptible to the effects of
9 ETS than are older children (U.S. EPA, 1992).
10 Household ETS exposure is an important issue because many people, especially young children, spend
11 much time inside their homes. Based on data reported from the 1994 National Health Interview Survey,
12 the Department of Health and Human Services (DHHS) estimates that 27 percent of children aged 6 years
13 and younger are exposed to ETS in the home (U.S. DHHS, 2000).
14 Exposure to ETS leaves traces of specific chemicals in people's blood, urine, saliva, and hair. Cotinine is
15 a chemical that forms inside the body following exposure to nicotine, an ingredient in all tobacco
16 products and a component of ETS. Following nicotine exposures, cotinine can usually be detected in
17 blood for at least 1 or 2 days (Pirkle et al., 1996). Active smokers almost always have blood cotinine
18 levels higher than 10 nanograms per milliliter (ng/mL), while non-smokers exposed to low levels of ETS
19 typically have blood concentrations less than 1 ng/mL (CDC, 2005). Following heavy exposure to ETS,
20 non-smokers can have blood cotinine levels between 1 and 10 ng/mL.
21 This indicator reflects blood cotinine concentrations in ng/mL among non-smokers for the U.S.
22 population, aged 3 years and older, as measured in the 1999-2000 and 2001-2002 National Health and
23 Nutrition Examination Survey (NHANES). NHANES is a series of surveys conducted by CDC's National
24 Center for Health Statistics (NCHS) that is designed to collect data on the health and nutritional status of
25 the civilian, non-institutionalized U.S. population using a complex, stratified, multistage, probability-
26 cluster design. Blood cotinine also was monitored in non-smokers aged 4 years and older as part of
27 NHANES III, between 1988 and 1991. CDC's National Center for Environmental Health (NCEH)
28 conducted the laboratory analyses for the biomonitoring samples. Beginning in 1999, NHANES became a
29 continuous and annual national survey.
30 What the Data Show
31 As part of NHANES III (1988-1991), CDC estimated that the median blood serum level (50th percentile)
32 of cotinine among non-smokers in the general U.S. population was 0.20 ng/mL. In NHANES 1999-2000,
33 the estimated median serum level among non-smokers nationwide was 0.06 ng/mL. During the 2001-
34 2002 survey, the estimated blood cotinine levels for the U.S. population were very similar to 1999-2000,
35 with the median concentration actually below the limit of detection, and the geometric mean 0.06 ng/mL
36 (see Exhibit 2-57). This marks a 70 percent decrease from levels measured in the 1988-1991 NHANES III
37 survey—a reduction that suggests a marked decrease in exposure to ETS.
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Exhibit 2-57. Blood cotinine concentrations for the non-smoking U.S. population age 3 years and older by
selected demographic groups, 1999-2002
for blood cotinine concentrations (ng/mL)
Total, age 3 years
and older
Sex
Male
Female
Race and ethnicity"
Black, non-Hispanic
Mexican American
White, non-Hispanic
Age group
3-11 years
12-19 years
20+ years
Survey years
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
Sample size
5,999
6,813
2,789
3,149
3,210
3,664
1,333
1,599
2,241
1,877
1,950
2,845
1,174
1,414
1,773
1,902
3,052
3,497
Geometric mean
NC
0.06
NC
0.08
NC
0.05
0.16
NC
0.06
NC
0.05
0.11
NC
0.09
NC
0.05
0.06
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Exhibit 2-58. Blood cotinine concentrations in U.S. children
age 4 to 17 by race and ethnicity, 1988-1994 and 1999-2002
White,
non-Hispanic
'88-94 '99-02 '88-94 '99-02 '88-94 '99-02 '88-'94 '99-02
Year
Cotinine concentrations are reported for non-smoking
children only.
Concentrations below 0.05 ng/mL are not presented
here because this was the detection limit for many ol
the samples.
Concentration:
0 0.05 to 1.0 ng/mL
D More than 1.0 ng/mL
Data source: Federal Interagency Forum on Child and Family Statistics, 2006. Data
collected by the National Health and Nutrition Examination Survey (NHANES).
Indicator Limitations
The measurement of an
environmental chemical in
a person's blood or urine
does not by itself mean that
the chemical has caused or
will cause harmful effects.
Because the data from
NHANES 1999-2000 and
2001-2002 represent only
two survey periods,
changes in estimates
between the two time
periods do not necessarily
reflect a trend. Earlier data
sets are available (e.g.,
NHANES III), but the data
are not directly comparable
to NHANES 1999-2002.
When CDC releases
additional survey results
(e.g., 2003-2004) it will
become possible to more
fully evaluate trends (CDC,
2002; 2004).
26 Data Sources
27 Data used for this indicator were extracted from two reports that present results of the ongoing National
28 Health and Nutrition Examination Survey (NHANES): the data shown in Exhibit 2-57 were obtained
29 from a CDC report (2005), and the data shown in Exhibit 2-58 were obtained from a report by the Federal
30 Interagency Forum on Child and Family Statistics (2005). The underlying laboratory data supporting both
31 reports are available online in SAS® transport file formats at:
32 htto: //www .cdc. gov/nchs/about/mai or/nhanes/datalink .htm.
33
References
34 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
35 environmental chemicals. NCEH Pub. No. 05-0570. July. Accessed September 9, 2005.
36
37 CDC (Centers for Disease Control and Prevention). 2004. NHANES analytic guidelines. June 2004
38 version. Accessed October 21, 2005.
39
40 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
41 NHANES III analytic guidelines. Last update August 30, 2002. Accessed October 11, 2005.
42
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1 Federal Interagency Forum on Child and Family Statistics. 2005. America's children: key national
2 indicators of well-being, 2005. Washington, DC: U.S. Government Printing Office. Accessed December
3 20, 2005.
4 IARC (International Agency for Research on Cancer). 2004. IARC working group on the evaluation of
5 carcinogenic risks to humans. Evaluation of carcinogenic risks to humans, volume 83: tobacco smoke and
6 involuntary smoking. Lyon, France.
7 NTP (National Toxicology Program) 2002. Report on carcinogens, 10th Edition.
8 Pirkle JL, Flegal KM, Bernert JT, Brody DJ, Etzel RA, Maurer KR. 1996. Exposure of the U.S.
9 population to environmental tobacco smoke: the third national health and nutrition examination survey,
10 1988 to 1991.J. Amer. Med. Assoc. 275:1233-1240.
11 U.S. DHHS (Department of Health and Human Services). 2000. Healthy people 2010. 2nd ed. With
12 understanding and improving health and objectives for improving health. 2 vols. Washington, DC: U.S.
13 Government Printing Office
14
15 U.S. EPA. 1992. Respiratory health effects of passive smoking: lung cancer and other disorders.
16 Washington, D C.
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1 2.4.3 Discussion
2 What These Indicators Say About Trends in Indoor Air Quality and Their
3 Effects on Human Health
4 The two indoor air quality indicators provide insights into issues of very different origin: radon is a
5 substance from a natural source, while environmental tobacco smoke (as evaluated by the presence of
6 blood cotinine) is linked entirely to human behavior.
7 The Homes Above EPA's Radon Action Level indicator (p. 2-111) tracks two statistics: the number of
8 homes estimated to be at or above EPA's action level (4 pCi/L) for radon, and the number of homes with
9 operating radon mitigation systems. Evaluating trends in radon mitigation systems is relevant because
10 properly operated systems are expected to reduce radon to levels below the action level, and therefore
11 also are expected to reduce radon-related health risks among building occupants. Between 1990 and 2004,
12 the number of homes with radon mitigation systems increased nearly four-fold, but these homes account
13 for less than 10 percent of the nation's homes currently believed to have radon levels greater than EPA's
14 action level. Some residents are being protected against radon exposures through radon-resistant new
15 construction techniques used when a home is built. Estimates of radon-resistant new construction
16 practices are not included in the indicator, however, because while they substantially reduce radon levels
17 in homes with high radon potential, they do not always reduce the levels below the action level.
18 The Blood Cotinine indicator (p. 2-114) tracks blood concentrations of cotinine, a metabolite of nicotine,
19 and shows that exposure to environmental tobacco smoke among non-smokers decreased considerably in
20 the last decade. This decrease was observed for all population groups, defined by age (including children),
21 sex, and ethnicity. However, children's blood cotinine levels, on average, are still more than twice the
22 levels observed in adults. A logical explanation for the downward trend in blood cotinine levels is
23 modified behavior, whether reduced smoking prevalence or more widespread practices of restricting areas
24 in which individuals are allowed to smoke.
25 Taken together, these indicators show an increasing number of Americans have reduced indoor air
26 exposures to two known carcinogens. Though these improvements are encouraging, both radon and
27 environmental tobacco smoke remain important indoor air quality issues.
28 Limitations, Gaps, and Challenges
29 The two indicators in this section provide extensive, but not comprehensive, information on the
30 corresponding indoor air quality issues that they characterize. An important limitation of the Homes
31 Above EPA's Radon Action Level indicator, for instance, is that it does not track the number of homes
32 designed and built with radon-resistant new construction features, which can prevent radon from entering
33 homes and therefore reduce radon exposures and associated health risks. Thus, more people are likely
34 being protected from elevated indoor air exposures to radon than suggested by trends in radon mitigation
35 systems alone.
36 The Blood Cotinine indicator also has certain limitations. For example, exposure to environmental
37 tobacco smoke does not occur exclusively indoors: some proportion of blood cotinine levels measured in
38 non-smokers reflects exposures that occurred outdoors. In addition, nationally representative blood
39 cotinine data are not available for children under 3 years old—an age group with documented
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1 susceptibilities to environmental tobacco smoke.37 Nonetheless, none of these limitations call into
2 question this indicator's main finding: nationwide, exposures to environmental tobacco smoke among
3 non-smokers are decreasing. Moreover, reliable survey data on smoking behavior corroborates this
4 downward trend.38
5 The two indoor air quality indicators provide useful insights into trends for radon and environmental
6 tobacco smoke, but they leave some gaps that EPA would like to fill to better answer the overarching
7 question on nationwide indoor air quality trends and associated health effects. For example, ROE
8 indicators could not be developed for indoor air quality trends for molds, some combustion products,
9 chemicals found in common household cleaners and building materials, and certain persistent pollutants
10 and endocrine disrupters that have been identified in household dust. 39>4° There is no quantitative,
11 nationally representative inventory of emission sources in indoor environments, nor is there a nationwide
12 monitoring network that routinely measures air quality inside homes, schools, and office buildings. These
13 gaps in nationwide indicators do not mean that nothing is known about the broad range of indoor air
14 quality issues and associated health effects. Rather, information on these issues can be gleaned from
15 numerous publications by governmental agencies and in the scientific literature. Data from these other
16 publications and information resources, though valuable in understanding indoor air quality, are not
17 presented in this report as indicators because they are not sufficiently representative on a national scale or
18 because they do not track an issue over time.
19 The challenges associated with filling these indicator gaps are well known. Although methods to monitor
20 indoor air quality are available, there is considerable variability among building types, occupants'
21 behaviors, climate conditions, and ventilation systems for indoor environments in the U.S. This
22 variability, combined with access issues and the number of different pollutants to address, makes a
23 statistically based evaluation of our nation's millions of residences, thousands of office buildings, and
24 more than 100,000 schools a challenging and resource-intensive task. Further, it is difficult to directly
25 measure how changes in indoor air quality translate into corresponding changes in human health effects,
26 because many health outcomes attributed to poor indoor air quality (e.g., asthma attacks) have numerous
27 environmental and non-environmental risk factors.
37 U.S. EPA. 1992. Respiratory health effects of passive smoking: lung cancer and other disorders. EPA/600/6-
90/006F. Washington, DC.
38 U.S. Department of Health and Human Services. 2000. Healthy people 2010: understanding and improving health.
2nd ed. Washington, DC: U.S. Government Printing Office. November,
39 Rudel, R.A., D.E. Camann, J.D. Spengler, L.R. Korn, and J.G. Brody. 2003. Phthalates, alkylphenols, pesticides,
polybrominated diphenyl ethers, and other endocrine-disrupting compounds in indoor air and dust. Env. Sci. Tech.
37(20):4543-4553.
40 Stapleton, H.M., N.G. Dodder, J.H. Offenberg, M.M. Schantz, and S.A. Wise. 2005. Polybrominated diphenyl
ethers in house dust and clothes dryer lint. Env. Sci. Tech. 39(4):925-931.
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CHAPTER 3
WATER
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WATER CHAPTER CONTENTS
3.1 INTRODUCTION 3-6
3.1.1 Overview of the Data 3-7
3.1.2 Organization of This Chapter 3-8
3.2 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF FRESH SURFACE WATERS
AND THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 3-11
3.2.1 Introduction 3-11
3.2.2 ROE Indicators 3-12
INDICATOR: High and Low Stream Flows 3-14
INDICATOR: Streambed Stability in Wadeable Streams 3-19
INDICATOR: Nitrogen and Phosphorus in Wadeable Streams 3-22
INDICATOR: Nitrogen and Phosphorus in Streams in Agricultural Watersheds 3-25
INDICATOR: Nitrogen and Phosphorus Discharge from Large Rivers 3-28
INDICATOR: Pesticides in Streams in Agricultural Watersheds 3-32
INDICATOR: Benthic Macroinvertebrates in Wadeable Streams 3-35
3.2.3 Discussion 3-39
What These Indicators Say About Trends in the Extent and Condition of Fresh Surface
Waters and Their Effects on Human Health and the Environment 3-39
Limitations, Gaps, and Challenges 3-40
3.3 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF GROUND WATER AND
THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 3-41
3.3.1 Introduction 3-41
3.3.2 ROE Indicators 3-43
INDICATOR: Nitrate and Pesticides in Shallow Ground Water in Agricultural
Watersheds 3-44
3.3.3 Discussion 3-48
What This Indicator Says About Trends in the Extent and Condition of Ground Water
and Their Effects on Human Health and the Environment 3-48
Limitations, Gaps, and Challenges 3-48
3.4 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF WETLANDS AND THEIR
EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 3-50
3.4.1 Introduction 3-50
3.4.2 ROE Indicators 3-52
INDICATOR: Wetland Extent, Change, and Sources of Change 3-53
3.4.3 Discussion 3-57
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What This Indicator Says About Trends in the Extent and Condition of Wetlands and
Their Effects on Human Health and the Environment 3-57
Limitations, Gaps, and Challenges 3-57
3.5 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF COASTAL WATERS AND
THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 3-59
3.5.1 Introduction 3-59
3.5.2 ROE Indicators 3-60
INDICATOR: Trophic State of Coastal Waters 3-62
INDICATOR: Coastal Sediment Quality 3-67
INDICATOR: Coastal Benthic Communities 3-71
INDICATOR: Submerged Aquatic Vegetation in the Chesapeake Bay 3-74
INDICATOR: Hypoxia in the Gulf of Mexico and Long Island Sound 3-77
INDICATOR: Harmful Algal Bloom Outbreaks Along the Western Florida Coastline .3-
81
3.5.3 Discussion 3-84
What These Indicators Say About Trends in the Extent and Condition of Coastal Waters
and Their Effects on Human Health and the Environment 3-84
Limitations, Gaps, and Challenges 3-85
3.6 WHAT ARE THE TRENDS IN THE QUALITY OF DRINKING WATER AND THEIR
EFFECTS ON HUMAN HEALTH? 3-87
3.6.1 Introduction 3-87
3.6.2 ROE Indicators 3-89
INDICATOR: Population Served by Community Water Systems with No Reported
Violations of Health-Based Standards 3-90
3.6.3 Discussion 3-94
What This Indicator Says About Trends in the Quality of Drinking Water and Their
Effects on Human Health 3-94
Limitations, Gaps, and Challenges 3-94
3.7 WHAT ARE THE TRENDS IN THE CONDITION OF RECREATIONAL WATERS AND
THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 3-96
3.7.1 Introduction 3-96
3.7.2 ROE Indicators 3-97
3.7.3 Discussion 3-98
Limitations, Gaps, and Challenges 3-98
3.8 WHAT ARE THE TRENDS IN THE CONDITION OF CONSUMABLE FISH AND
SHELLFISH AND THEIR EFFECTS ON HUMAN HEALTH? 3-99
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3.8.1 Introduction 3-99
3.8.2 ROE Indicators 3-101
INDICATOR: Coastal Fish Tissue Contaminants 3-103
INDICATOR: Contaminants in Lake Fish Tissue 3-107
3.8.3 Discussion 3-111
What These Indicators Say About Trends in the Condition of Consumable Fish and
Shellfish and Their Effects on Human Health 3-111
Limitations, Gaps, and Challenges 3-111
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1 3.1 INTRODUCTION
2 The nation's water resources have immeasurable value. These resources encompass lakes, streams,
3 ground water, coastal waters, wetlands, and other waters; their associated ecosystems; and the human uses
4 they support (e.g., drinking water, recreation, and fish consumption). The extent of water resources (their
5 amount and distribution) and their condition (physical, chemical, and biological attributes) are critical to
6 ecosystems, human uses, and the overall function and sustainability of the hydrologic cycle.
7 Because the extent and condition of water can affect human health, ecosystems, and critical
8 environmental processes, protecting water resources is integral to EPA's mission. EPA works in
9 partnership with other government agencies that are also interested in the extent and condition of water
10 resources, both at the federal level and at the state, local, or tribal level.
11 In this chapter, EPA seeks to assess national trends in the extent and condition of water, stressors that
12 influence water, and associated exposures and effects among humans and ecological systems. The ROE
13 indicators in this chapter address seven fundamental questions about the state of the nation's waters:
14
15 • What are the trends in extent and condition of fresh surface waters? This question focuses
16 on the nation's rivers, streams, lakes, ponds, and reservoirs.
17 • What are the trends in extent and condition of ground water? This question addresses
18 subsurface water that occurs beneath the water table in fully saturated soils and geological
19 formations.
20 • What are the trends in extent and condition of wetlands? Wetlands—including swamps,
21 bogs, marshes, and similar areas—are areas inundated or saturated by surface or ground water
22 often enough and long enough to support a prevalence of vegetation typically adapted for life
23 in saturated soil conditions.
24 • What are the trends in extent and condition of coastal waters? Indicators in this report
25 present data for coastal waters that are generally within 3 miles of the coastline (except the
26 Hypoxia in the Gulf of Mexico and Long Island Sound indicator).
27 • What are the trends in the quality of drinking water? People drink tap water, which comes
28 from both public and private sources, and bottled water. Sources of drinking water can
29 include both surface water (rivers, lakes, and reservoirs) and ground water.
30 • What are the trends in the condition of recreational waters? This question addresses water
31 used for a wide variety of purposes, such as swimming, fishing, and boating.
32 • What are the trends in the condition of consumable fish and shellfish? This question focuses
33 on the suitability offish and shellfish for human consumption.
34 These ROE questions are posed without regard to whether indicators are available to answer them. This
35 chapter presents the indicators available to answer these questions, and also points out important gaps
36 where nationally representative data are lacking.
37 Each of the seven questions is addressed in a separate section of this chapter. However, all the questions
38 are fundamentally connected—a fact that is highlighted throughout the chapter text and indicator
39 summaries. All water is part of the global hydrologic cycle, and thus it is constantly in motion—whether
40 it is a swiftly flowing stream or a slow-moving aquifer thousands of years old. A stream may empty into a
41 larger river that ultimately discharges into coastal waters. An aquifer may be recharged by surface waters,
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1 or feed surface waters or wetlands through springs and seeps. In each case, the extent and condition of
2 one water resource can affect the extent and condition of another type. One example of this
3 interdependence can be found in the movement of nutrients. Together, several of the ROE indicators track
4 nutrient levels in water bodies ranging from small wadeable streams to the coastal waters. Additional
5 ROE indicators describe some of the effects that may be associated with excess nutrients, such as
6 eutrophication and hypoxia.
7 In addition to the links within the water cycle, there are many connections between the extent and
8 condition of water and other components of the environment. Air (addressed in Chapter 2), land (Chapter
9 4), and water all are environmental media, and the condition of one medium can influence the condition
10 of another. For example, contaminants can be transferred from air to water via deposition, or from land to
11 water through runoff or leaching.
12 Chapter 5, Human Health, and Chapter 6, Ecological Condition, examine the relationships between
13 human life, ecosystems, and some of the environmental conditions that can affect them. Humans and
14 ecosystems depend on water, so stressors that affect the extent and condition of water—like droughts,
15 pathogens, and contaminants—may ultimately affect human health or ecological condition.
16 3.1.1 Overview of the Data
17 The indicators in this chapter reflect several different methods of collecting and analyzing data on the
18 extent and condition of water resources (and in some cases, indicators employ a combination of methods).
19 Some of the indicators in this chapter are based on probabilistic surveys, with sample or monitoring
20 locations chosen to be representative of a large area (e.g., an EPA Region or the nation as a whole).
21 Examples of probabilistic surveys include EPA's Wadeable Streams Survey and National Coastal
22 Assessment, and the U.S. Fish and Wildlife Service's Wetlands Status and Trends Survey. Other
23 indicators reflect targeted sampling or monitoring—for example, collecting water samples in an area
24 prone to hypoxia in order to ascertain the extent and duration of a particular hypoxic event. In some cases,
25 data are based on regulatory reporting, which may in turn reflect probabilistic or targeted sampling. For
26 example, the ROE indicator on drinking water is based on review of monitoring conducted by water
27 systems, with results reported by the states to EPA, as required by federal law.
28 One of the challenges in assessing the extent and condition of water resources is that a single data
29 collection method is rarely perfect for every combination of spatial and temporal domains. In general,
30 there is an inherent tradeoff in representing trends in water resources. For example, a probabilistic survey
31 may provide an accurate representation of national trends, but the resolution may be too low to
32 definitively characterize the resource at a smaller scale. In some cases, results can be disaggregated to the
33 scale of EPA Regions or ecoregions without losing precision. However, these indicators are generally not
34 designed to inform the reader about the condition of his or her local water bodies, for example, or the
35 quality of locally harvested fish.
36 Likewise, it is often convenient to compare trends in terms of annual averages—particularly where it is
37 not practical to collect data every day of the year. However, averaging and periodic sampling can obscure
38 or overlook extreme events, such as spikes in water contaminants after a pesticide application or a large
39 storm. Thus, representative extent or condition data cannot depict the full range of variations and
40 extremes—some of which may be critical to ecosystems or to humans—that occur in smaller areas or on
41 smaller time scales.
42 This chapter presents only data that meet the ROE indicator definition and criteria (see Chapter 1,
43 Introduction). Note that non-scientific indicators, such as administrative and economic indicators, are not
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1 included in this definition. Thorough documentation of the indicator data sources and metadata can be
2 found online at [insert url]. All ROE indicators were peer-reviewed during an independent peer review
3 process (see [insert url] for more information). Readers should not infer that the indicators in this chapter
4 reflect the complete state of knowledge. Many other data sources, publications, and site-specific research
5 projects have contributed substantially to the current understanding of status and trends in water, but are
6 not included in this report because they do not meet the ROE indicator criteria.
7 3.1.2 Organization of This Chapter
8 The remainder of this chapter is organized into seven sections corresponding to the seven questions that
9 EPA seeks to answer about trends in water. Each section introduces the question and its importance,
10 presents the ROE indicators used to help answer the question, and discusses what the indicators, taken
11 together, say about the question. The ROE indicators include National Indicators as well as several
12 Regional Indicators that meet the ROE definition and criteria and help to answer a question at a smaller
13 geographic scale. Each section concludes by highlighting the major challenges to answering the question
14 and identifying important information gaps.
15 The table below shows the indicators used to answer each of the questions in this chapter and their
16 location within this report.
17
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1 Table 3.1.1. Water—ROE Questions and Indicators
Question
What are the trends in extent and condition of
fresh surface waters and their effects on
human health and the environment?
Indicator Name
High and Low Stream Flows (N)
Streambed Stability in Wadeable
Streams (N)
Lake and Stream Acidity (N)
Nitrogen and Phosphorus in
Wadeable Streams (N)
Nitrogen and Phosphorus in
Streams in Agricultural
Watersheds (N)
Nitrogen and Phosphorus
Discharge from Large Rivers
(N)
Pesticides in Streams in
Agricultural Watersheds (N)
Benthic Macroinvertebrates in
Wadeable Streams (N)
Section Page
3.2.2 3-14
3.2.2 3-19
2.2.2 2-62
3.2.2 3-22
3.2.2 3-25
3.2.2 3-28
3.2.2 3-32
3.2.2 3-35
What are the trends in extent and condition of
ground water and their effects on human
health and the environment?
Nitrate and Pesticides in Shallow
Ground Water in Agricultural
Areas (N)
3.3.2 3-44
What are the trends in extent and condition of
wetlands and their effects on human health
and the environment?
What are the trends in extent and condition of
coastal waters and their effects on human
health and the environment?
What are the trends in the quality of drinking
water and their effects on human health?
Wetland Extent, Change, and
Sources of Change (N)
Wetland Extent, Change, and
Sources of Change (N)
Trophic State of Coastal Waters
(N/R)
Coastal Sediment Quality (N/R)
Coastal Benthic Communities
(N/R)
Coastal Fish Tissue Contaminants
(N/R)
Submerged Aquatic Vegetation in
the Chesapeake Bay (R)
Hypoxia in the Gulf of Mexico and
Long Island Sound (R)
Harmful Algal Bloom Outbreaks
Along the Western Florida
Coastline (R)
Population Served by Community
Water Systems with No
Reported Violations of Health-
Based Standards (N/R)
3.4.2 3-53
3.4.2 3-53
3.5.2 3-62
3.5.2 3-67
3.5.2 3-71
3.8.2 3-103
3.5.2 3-74
3.5.2 3-77
3.5.2 3-81
3.6.2 3-90
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1
2
3
4
Question
What are the trends in the condition of
recreational waters and their effects on human
health and the environment?
What are the trends in the condition of
consumable fish and shellfish and their effects
on human health?
Indicator Name
No ROE indicators
Coastal Fish Tissue Contaminants
(N/R)
Contaminants in Lake Fish Tissue
(N)
Section Page
3.8.2 3-103
3.8.2 3-107
N = National Indicator
R = Regional Indicator
N/R = National Indicator displayed at EPA Regional scale
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1 3.2 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF FRESH
2 SURFACE WATERS AND THEIR EFFECTS ON HUMAN HEALTH AND THE
3 ENVIRONMENT?
4 3.2.1 Introduction
5 Though lakes, ponds, rivers, and streams hold less than one thousandth of a percent of the water on the
6 planet, they serve many critical functions for the environment and for human life. These fresh surface
7 waters sustain ecological systems and provide habitat for many plant and animal species. They also
8 support a myriad of human uses, including drinking water, irrigation, wastewater treatment, livestock,
9 industrial uses, hydropower, and recreation. Fresh surface waters also influence the extent and condition
10 of other water resources, including ground water, wetlands, and coastal systems downstream.
11 The extent of fresh surface waters reflects the influence and interaction of many stressors. It can be
12 affected by direct withdrawal for drinking, irrigation, industrial processes, and other human use, as well
13 as by the withdrawal of ground water, which replenishes many surface waters. Hydromodifications such
14 as dam construction can create new impoundments and fundamentally alter stream flow. Land cover can
15 affect drainage patterns (e.g., impervious pavement may encourage runoff or flooding). Weather
16 patterns—e.g., the amount of precipitation, the timing of precipitation and snowmelt, and the conditions
17 that determine evaporation rates—also affect the extent of fresh surface waters. Changing climate could
18 also affect the extent of fresh surface water that is available.
19 The condition of fresh surface waters reflects a range of characteristics. Physical characteristics include
20 attributes such as temperature and clarity. Chemical characteristics include attributes such as salinity,
21 nutrients, and chemical contaminants (including contaminants in sediments, which can impact water
22 quality and potentially enter the aquatic food web). Biological characteristics include diseases, pathogens,
23 and—in a broader sense—the status of plant and animal populations and the condition of their habitat. In
24 addition to their effects on the environment, many of these characteristics can ultimately affect human
25 health, mainly through drinking water, recreational activities (e.g., health effects in swimmers from
26 pathogens and harmful algal blooms), or consumption offish and shellfish. Because these three topics are
27 complex and encompass many types of water bodies, each is addressed in greater detail in its own section
28 of this report (see Sections 3.6, 3.7, and 3.8, respectively).
29 Like extent, the condition of fresh surface waters can be influenced by a combination of natural and
30 anthropogenic stressors, such as:
31 • Point source pollution, including contaminants discharged directly into water bodies by
32 industrial operations, as well as nutrients and contaminants in sewage. Even treated sewage
33 contains nutrients that affect the chemical composition of the water.
34 • Nonpoint source pollution, which largely reflects contaminants, nutrients, and excess
35 sediment in runoff from urban and suburban areas (e.g., stormwater) and agricultural land.
36 Other sources include recreational activities (e.g., boating and marinas) and acid mine
37 drainage. Nonpoint source pollution can be influenced by land use—e.g., certain forestry
38 techniques and agricultural practices that encourage runoff and erosion. Nonpoint sources
39 tend to be more variable than point sources. For example, pesticide concentrations in streams
40 reflect the location and timing of pesticide application.
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1 • Air deposition. Acidic aerosols, heavy metals, and other airborne contaminants may be
2 deposited directly on water or may wash into water bodies after deposition on land. Air
3 deposition is a major source of mercury, for example.
4 • Invasive species. Invasives are non-indigenous plant and animal species that can harm the
5 environment, human health, or the economy.1 Invasive species can crowd out native species,
6 and also may alter the physical and chemical condition of water bodies.
7 • Natural factors. Precipitation determines the timing and amount of runoff and erosion, while
8 other aspects of weather and climate influence heating, cooling, and mixing in lakes—which
9 affect the movement of contaminants and the cycling of nutrients. The mineral composition
10 of bedrock and sediment helps determine whether a water body may be susceptible to
11 acidification.
12 The condition of fresh surface waters also may be influenced by extent. Stream flow patterns influence
13 contaminant and sediment loads, while changes in the shape of water bodies—e.g., eliminating deep pools
14 or creating shallow impoundments—can change water temperature. The extent of surface waters also
15 represents the extent of habitat—a key aspect of biological condition. Some plant and animal
16 communities are sensitive to water level (e.g., riparian communities), while others may be adapted to
17 particular seasonal fluctuations in flow. Stressors that affect extent may ultimately affect the condition of
18 freshwater habitat—for example, hydromodifications that restrict the migration of certain fish species.
19 3.2.2 ROE Indicators
20 Eight ROE indicators characterize either the extent or the condition of fresh surface waters (Table 3.2.1).
21 One of these indicators presents information about stream flow patterns, an aspect of surface water extent.
22 The other seven indicators characterize various aspects of condition, including the physical condition of
23 sediments, the condition of benthic communities, and the chemical condition of the water itself. Several
24 of these indicators track concentrations of nutrients, which can impact many different types of water
25 bodies if present in excess (e.g., through eutrophication). Supporting data come from several national
26 monitoring programs: EPA's Environmental Monitoring and Assessment Program (EMAP), EPA's
27 Wadeable Streams Assessment (WSA), EPA's Temporally Integrated Monitoring of Ecosystems (TIME)
28 and LTM (Long-Term Monitoring) projects, and three programs administered by the U.S. Geological
29 Survey (the National Water Quality Assessment [NAWQA] program, the National Stream Quality
30 Accounting Network [NASQAN], and the USGS stream gauge network).
1 National Invasive Species Council. 2005. Five year review of Executive Order 13112 on invasive species.
Washington, DC: U.S. Department of the Interior.
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1 Table 3.2.1. ROE Indicators of the Trends in Extent and Condition of Fresh Surface Waters and
2 their Effects on Human Health and the Environment
NATIONAL INDICATORS
High and Low Stream Flows
Streambed Stability in Wadeable Streams
Lake and Stream Acidity
Nitrogen and Phosphorus in Wadeable Streams
Nitrogen and Phosphorus in Streams in Agricultural Watersheds
Nitrogen and Phosphorus Discharge from Large Rivers
Pesticides in Streams in Agricultural Watersheds
Benthic Macroinvertebrates in Wadeable Streams
LOCATION
3.2.2 -p. 3-14
3.2.2 -p. 3-19
2.2.2 -p. 2-62
3.2.2 -p. 3-22
3.2.2 -p. 3-25
3.2.2 -p. 3-28
3.2.2 -p. 3-32
3.2.2 -p. 3-35
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INDICATOR: High and Low Stream Flows
2 Flow is a critical aspect of the physical structure of stream ecosystems (Poff and Allan, 1995; Robinson et
3 al., 2002). High flows shape the stream channel and clear silt and debris from the stream, and some fish
4 species depend on high flows for spawning. Low flows define the smallest area available to stream biota
5 during the year. In some cases, the lowest flow is no flow at all—particularly in arid and semi-arid
6 regions where intermittent streams are common. Riparian vegetation and aquatic life in intermittent
7 streams have evolved to complete their life histories during periods when water is available; however,
8 extended periods of no flow can still impact their survival (Fisher, 1995). The timing of high and low
9 flows also influences many ecological processes. Changes in flow can be caused by dams, water
10 withdrawals, ground water pumping (which can alter base flow), changes in land cover (e.g.,
11 deforestation or urbanization), and weather and climate (Calow and Petts, 1992).
12 This indicator, which combines two indicators presented by The Heinz Center (2005), reports on trends in
13 two aspects of stream flow:
14 • Flow magnitude and timing: This part of the indicator reports the percentage of streams or
15 rivers throughout the contiguous 48 states that experienced major changes in the magnitude
16 or the timing of average annual 1-day high flows or 7-day low flows in the 1970s, 1980s, or
17 1990s, compared to a 20-year baseline period between 1930 and 1949. This indicator is based
18 on 867 USGS stream gauging sites with 20 years of continuous discharge records during the
19 baseline period and continuous records for the three decades between 1970 and 1999.
20 • No-flow periods: This part of the indicator describes trends in no-flow periods in grassland
21 and shrubland areas of the contiguous 48 states. These areas were selected for further analysis
22 because they are largely arid or semi-arid, and therefore relatively water-stressed. This part of
23 the indicator has two components. The first component reports the percentage of
24 grassland/shrubland streams in which no-flow periods occurred during the 1950s, 1960s,
25 1970s, 1980s, or 1990s. The second component reports the percentage of these streams in
26 which the duration of no-flow periods during each of these decades represents an increase or
27 decrease of more than 50 percent compared to the 50-year (1950-1999) average for that
28 stream. Data were collected from USGS stream gauges in watersheds where at least 50
29 percent of the land cover is considered grassland or shrubland per the National Land Cover
30 Dataset (NLCD). These land cover designations generally correspond with three ecoregion
31 types: Grassland/Steppe, California/Mediterranean, and Desert/Shrub (Bailey, 1995). The
32 first component (percentage with no-flow periods) is based on 408 gauging sites; the second
33 component (duration of no-flow periods) is based on 143 of these sites that had at least one
34 no-flow day between 1950 and 1999.
35 What the Data Show
36 More than half of the streams and rivers showed changes of 75 percent or more in their high or low flows
37 or a shift of 60 days or more in the timing of their high or low flows, compared to the period 1930-1949
38 (Exhibit 3-1). This percentage increased from 55 percent in the 1970s to 61 percent in the 1990s. About
39 one-third of the streams showed moderate changes in flow (25-75 percent) or timing (30-60 days). Only
40 10 percent of the streams and rivers had minimal alterations of flow of less than 25 percent or timing of
41 fewer than 30 days, compared to the historical baseline period.
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1 Exhibit 3-2 provides more detail about the nature of
2 "major changes" in stream flow between the historical
3 reference period (1930-1949) and the 1970s-1990s
4 period of record. Notable trends include:
5 • Approximately two-thirds of streams had
6 major changes in the volume of low flow,
7 with about one-third of streams showing
8 substantially larger low flows throughout
9 the period of record (panel A) and another
10 one-third showing substantially smaller
11 low flows (panel B).
12 • In terms of high flow volume, more
13 streams showed major decreases than
14 major increases. In the 1970s and 1980s,
15 only 12 percent of streams had
16 substantially larger high-flow volumes
17 than they had from 193 0 to 1949, although
18 this figure jumped to 31 percent in the
19 1990s (panel D). In contrast, throughout
20 the 1970s, 1980s, and 1990s, nearly 40
21 percent of streams exhibited smaller high
22 flows than they had during the reference
23 period (panel E).
24 • Between the reference period and the
25 1970s-1990s period of record, about 30
26 percent of streams showed major changes
27 in the timing of low flows (panel C), and
28 42 to 47 percent showed major changes in
29 the timing of high flows (panel F). The
30 number of streams in each of these
31 categories increased somewhat between
32 the 1970s and the 1990s.
Exhibit 3-1. Alteration of high and low flow in rivers
and streams in the contiguous U.S., 1970s-1990s,
compared with 1930-1949 baseline3
IUU
80
of streams
§
§ 40
£
20
0
9.5
35.4
55.1
9.7
33.5
56.9
9.2
30.0
60.8
1970s 1980s 1990s
Decade
Degree of alteration:
D Minimal
D Moderate0
D Major11
"Coverage: 867 stream gauging sites
in the contiguous U.S. with
continuous discharge measurements
from 1930 to 1949 and from 1970
to 1999.
bMinimal: Less than 25% increase
or decrease in flow, or less than a
30-day change in timing of low or high flow.
'Moderate: Between 25% and 75% increase or decrease in flow,
or a 30- to 60-day change in timing of low or high flow.
dMajor: More than 75% increase or decrease in flow, or more than
a 60-day change in timing of low or high flow.
Data source: Heinz Center, 2005. Data collected by USGS, with
analysis by Raff and Poff, 2001.
33 Overall, the percentage of streams and rivers in grassland and shrubland regions of the United States with
34 periods of no flow decreased from 24 percent in the 1950s to 14 percent in the 1990s, with some variation
35 by ecoregion (Exhibit 3-3). Among streams experiencing periods of no flow, the duration of these periods
36 also decreased between the 1950s and 1990s (Exhibit 3-4). In the 1950s, 38 percent of these streams and
37 rivers experienced no-flow periods that were at least 50 percent longer than their long-term average no-
38 flow periods during 1950-1999. By the 1990s, only 10 percent of streams fell into this category. The
39 percentage of streams with no-flow periods at least 50 percent shorter than their long-term average
40 increased from 23 percent in the 1950s to 63 percent in the 1990s, with a peak of 64 percent in the 1980s.
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3-15
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Exhibit 3-2. Major changes in high and low flow in rivers and streams of the contiguous U.S.,
1970s-1990s, compared with 1930-1949 baseline"b
50
10
A. Increased low Hows
B. Decreased low flows
C. Change in low flow timing
30.6
35.3
37.5
30.9
26.4
28.5
27.5
28.7
31.6
1970s 1980s 1990s
D. Increased high flows
1970s 1980s 1990s
E. Decreased high flows
1970s 1980s 1990s
F. Change in high flow timing
au
40
30
20
10
I)
30.6
12.0 11.8
35.9 38.5 37.7
41 '5 46.9 47.1
1970s
1980s
1970s
1980s
1970s
1980s
Decade
"Coverage: 867 stream gauging sites in the contiguous U.S. with continuous discharge measurements from 1930 to 1949 and from 1970 to 1999.
bBased on 7-day low flows and 1 -day high flows. "Major" changes involve at least a 75% increase or decrease in flow or at least a 60-day shift
in timing.
Data soiling: Heinz Center, 2005. Data collected by USSS, with analysis by Raff and Poff, 2001.
Exhibit 3-3. Percentage of grassland/shrubland
streams in the contiguous U.S. experiencing
periods of no flow, by ecoregion, 1950s-1990sa'b
Exhibit 3-4. Duration of no-flow periods in
intermittent grassland/shrubland streams of the
contiguous U.S., 1950s-1990s'
£ 20
Grassland/ California/ Desert/ All three of
Steppe ecoregion Mediterranean Shrub ecoregion these ecoregions
ecoregion
IllU
'50s 70s '90s '50s 70s '90s '60s 70s '90s '50s 70s '90s
Ecoregion divisions
/Desert/Shrub
—i^ f
Year
'Coverage: 408 stream gauging sites
within 4-digit Hydrologic Unit Code
(HUC4) watersheds containing 50
percent or greater grass/shrub cover,
and with continuous discharge
measurements from 1950 to 1999.
Grass/shrub cover refers to National
Land Cover Dataset (NLCD) classes
31,51, and 71
(http://landcover.usgs.gov/classes.asp).
bEcoregions based on Bailey, 1995.
Data source: Heinz Center, 2005. Data collected by USGS, with
analysis by Raff, 2001 and Raff et al., 2001.
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California/ Grassland/
Mediterranean Steppe
Duration ol
no-flow periods:
Substantially
longer
« Substantially
shorter
1950s 1960s
1970s 1980s
Decade
1990s
Coverage: Stream gauging sites within 4-digit Hydrologic Unit
Code (HUC4) watersheds containing 50 percent or greater
grass/shrub cover, and with continuous discharge measurements
from 1950 to 1999. This analysis is limited to 143 sites that had
at least one no-flow day during this period. Grass/shrub cover
refers to National Land Cover Dataset (NLCD) classes 31, 51, and
71 (http://landcover.usgs.gov/classes.asp).
bA no-flow period is considered "substantially longer" if it is at
least twice as long as the 50-year average for a given stream, and
"substantially shorter" if it is 50% or less of the 50-year average.
A decade without any no-flow days qualifies as "substantially
shorter."
Data source: Heinz Center, 2005. Data collected by USGS, with
analysis by Raff, 2001 and Raffetal., 2001.
3-16
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1 Indicator Limitations
2 • The "magnitude and timing" component of this indicator compares stream flows in the
3 decades from 1970 to 1999 with a baseline period, 1930-1949. Many dams and other
4 waterworks had already been constructed by 1930, and this baseline period was characterized
5 by low rainfall in some parts of the country. However, a similar analysis based on data from
6 506 watersheds (USDA Forest Service, 2004) showed a tendency toward higher high- and
7 low-flow rates in the decades of the 1940s, 1950s, and 1960s compared to the earlier period
8 1879-1929.
9 • The "dry periods" component of this indicator compares stream flows in the decades from
10 1950 to 1999 with average stream flow over the full 50-year period. Like the baseline
11 discussed above, this long-term average does not represent the "natural state" of stream flow
12 because it postdates anthropogenic changes such as urbanization, construction of dams, etc.
13 • Although the sites analyzed here are spread widely throughout the U.S., gauge placement by
14 the USGS is not a random process. Gauges are generally placed on larger, perennial streams
15 and rivers, and changes seen in these larger systems may differ from those seen in smaller
16 streams and rivers.
17 Data Sources
18 The data presented in this indicator were originally published in Heinz Center (2005). The Heinz Center's
19 analysis was conducted by David Raff and N. LeRoy Poff, Colorado State University (Raff and Poff,
20 2001; Raff et al., 2001; Raff, 2001), using stream flow data from the USGS National Water Information
21 System database (USGS, 2005) (http://waterdata.usgs.gov/nwis). All data, including the 1930-1949
22 reference data, can be downloaded from this database. Ecoregions are based on Bailey (1995).
23 References
24 Bailey, R.G. 1995. Description of the ecoregions of the United States. Second ed. Misc. Publ. No. 1391
25 (rev). Washington, DC: USDA Forest Service.
26
27 Calow, P., and G.E. Petts, eds. 1992. The rivers handbook: hydrological and ecological principles.
28 Volume 1. Oxford, United Kingdom: Blackwell Scientific.
29 Fisher, S.G. 1995. Stream ecosystems of the western United States. In: Gushing, C.E., K.W. Cummings,
30 and G.W. Minshall, eds. River and stream ecosystems, ecosystems of the world 22. New York, NY:
31 Elsevier Press.
32 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. The state of the
33 nation's ecosystems: measuring the lands, waters, and living resources of the United States. New York,
34 NY: Cambridge University Press, September 2002. Web update 2005:
35
36 Poff, N.L., and J.D. Allan. 1995. Functional organization of stream fish assemblages in relation to
37 hydrologic variability. Ecology 76:606-27.
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1 Raff, D. 2001. Addendum to report on hydrologic alteration of rivers and streams in predominantly
2 grassland and shrubland ecosystems in support of the State of the Nation's Ecosystems project for The H.
3 John Heinz III Center. Colorado State University.
4 Raff, D., and N. Poff 2001. Final report on hydrologic alteration of rivers and streams in support of the
5 State of the Nation's Ecosystems project for The H. John Heinz III Center. Colorado State University.
6 Raff, D., S. Howard, and N. Poff. 2001. Report on hydrologic alteration of rivers and streams in
7 predominantly grassland and shrubland ecosystems in support of the State of the Nation's Ecosystems
8 project for The H. John Heinz III Center. Colorado State University.
9 Robinson, C.T., K. Tockner, and J.V. Ward. 2002. The fauna of dynamic riverine landscapes. Freshwater
10 Biol. 47:661-677.
11 USDA Forest Service. 2004. National report on sustainable forests—2003. Washington, DC.
12
13 USGS. 2005. National water information system. Accessed 2005.
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INDICATOR: Streambed Stability in Wadeable Stream
2 Streams and rivers adjust their channel shapes and particle sizes in response to the supply of water and
3 sediments from their drainage areas, and this in turn can affect streambed stability. Lower-than-expected
4 streambed stability is associated with excess sedimentation, which may result from inputs of fine
5 sediments from erosion—including erosion caused by human activities such as agriculture, road building,
6 construction, and grazing. Unstable streambeds may also be caused by increases in flood magnitude or
7 frequency resulting from hydrologic alterations. Lower-than-expected streambed stability may cause
8 stressful ecological conditions when, for example, excessive amounts of fine, mobile sediments fill in the
9 habitat spaces between stream cobbles and boulders. When coupled with increased stormflows, unstable
10 streambeds may also lead to channel incision and arroyo formation, and can negatively affect benthic
11 invertebrate communities and fish spawning (Kaufmann et al., 1999). The opposite condition—an overly
12 stable streambed—is less common, and generally reflects a lack of small sediment particles. Overly stable
13 streambeds can result from reduced sediment supplies or stream flows, or from prolonged conditions of
14 high sediment transport without an increase in sediment supply.
15 This indicator is based on the Relative Bed Stability (RBS), which is one measure of the interplay
16 between sediment supply and transport. RBS is the ratio of the observed mean streambed particle
17 diameter to the "critical diameter," the largest particle size the stream can move as bedload during
18 stormflows. The critical diameter is calculated from field measurements of the size, slope, and other
19 physical characteristics of the stream channel (Kaufmann et al., 1999). A high RBS score indicates a
20 coarser, more stable bed—i.e., streambed particles are generally much larger than the biggest particle the
21 stream could carry during a stormflow. A low RBS score indicates a relatively unstable streambed,
22 consisting of many fine particles that could be carried away by a stormflow. Expected values of RBS are
23 based on the statistical distribution of values observed at reference sites that are known to be relatively
24 undisturbed. RBS values that are substantially lower than the expected range are considered to be
25 indicators of ecological stress.
26 This indicator is based on data collected for the U.S. EPA's Wadeable Streams Assessment (WSA).
27 Wadeable streams are streams, creeks, and small rivers that are shallow enough to be sampled using
28 methods that involve wading into the water. They typically include waters classified as 1st through 4th
29 order in the Strahler Stream Order classification system (Strahler, 1952). The WSA is based on a
30 probabilistic design, so the results from representative sample sites can be used to make a statistically
31 valid statement about streambed stability in wadeable streams nationwide.
32 Crews sampled 1,392 randomized sites throughout the U.S. using standardized methods (U.S. EPA,
33 2004). Western sites were sampled between 2000 and 2004; eastern and central sites were all sampled in
34 2004. Sites were sampled between mid-April and mid-November. At each site, crews measured substrate
35 particle size, streambed dimensions, gradient, and stream energy dissipators (e.g., pools and woody
36 debris), then used these factors to calculate the RBS.
37 Because streambed characteristics vary geographically, streams were divided into nine ecoregions.2 In
38 each ecoregion, a set of relatively undisturbed sites was sampled in order to determine the range of RBS
For this analysis, the 48 contiguous states were divided into nine broad ecoregions. These "macro-level"
ecoregions were defined by the WSA based on groupings of EPA Level III ecoregions (for a map of EPA Level III
ecoregions, see http://www.epa.gov/wed/pages/ecoregions/level iii.htm). A map of the nine WSA ecoregions will
be available in the e-ROE.
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1 values that would be expected among "least disturbed" streams. Next, the RBS for every site was
2 compared to the distribution of RBS values among the ecoregion's reference sites. If the observed RBS
3 for a sample site was below the 5th or the 10th percentile of the regional reference distribution (depending
4 on the ecoregion), the site was classified as "most disturbed." This threshold was used because it offers a
5 high degree of confidence that the observed condition is statistically different from the "least disturbed"
6 reference condition. Streams with an RBS above the 25th percentile of the reference range were labeled
7 "least disturbed," indicating a high probability that the site is similar to the relatively undisturbed
8 reference sites. Streams falling between the 5th and 25th percentiles were classified as "moderately
9 disturbed." Note that the "least disturbed" category may include some streams with higher-than-expected
10 RBS values, which represent overly stable streambeds. Because it is more difficult to determine whether
11 overly stable streambeds are "natural" or result from anthropogenic factors, this indicator only measures
12 the prevalence of unstable streambeds (i.e., excess sedimentation).
Exhibit 3-5. Streambed stability in wadeable
streams of the contiguous U.S., 2000-2004"
D Not assessed/no data
D Least disturbed
D Moderately disturbed
D Most disturbed
"Compared with minimally
disturbed reference sites. See
text for definitions of the
categories shown in the figure
Data source: U.S. EPA,
Wadeable Streams
Assessment
80
60
40
20
n
5.3
50.1
19.7
24.9
What the Data Show
Roughly 50 percent of wadeable stream miles
are classified as "least disturbed" with respect to
streambed condition; that is, their streambed
stability is close to or greater than what would
be expected (Exhibit 3-5). Conversely, 25
percent of the nation's wadeable streambeds are
significantly less stable than regional reference
conditions for streambed stability ("most
disturbed"), and an additional 20 percent are
classified as "moderately disturbed."
Approximately 5 percent of the nation's stream
length could not be assessed because of missing
or inadequate sample data.
29 Indicator Limitations
30
31
32
33
34
35
36
Samples were taken one time from each sampling location during the index period (April-
November). Although the probability sampling design results in unbiased estimates for
relative streambed stability in wadeable streams during the study period, RBS values may be
different during other seasons and years because of variations in hydrology.
Trend data are unavailable because this is the first time that a survey on this broad scale has
been conducted, and the survey design does not allow trends to be calculated within a single
sampling period (2000-2004). These data will serve as a baseline for future surveys.
37 Data Sources
38 Aggregate data for this indicator were provided by EPA's Wadeable Streams Assessment (WSA) (U.S.
39 EPA, 2006b). Data from individual stream sites can be obtained from EPA's STORET database (U.S.
40 EPA, 2006a) (http://www.epa.gov/owow/streamsurvev/web data.html).
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1 References
2 Kaufmann, P.R., P. Levine, E.G. Robison, C. Seeliger, and D. Peck. 1999. Quantifying physical habitat in
3 wadeable streams. EPA/620/R-99/003. Washington, DC.
4
5 Strahler, A.N. 1952. Dynamic basis of geomorphology. Geol. Soc. Am. Bull. 63:923-938.
6 U.S. EPA. 2006a. Data from the Wadeable Streams Assessment. Accessed 2006.
7
8 U.S. EPA. 2006b. Wadeable Streams Assessment: a collaborative survey of the nation's streams. EPA
9 841-B-06-002. Washington, DC.
10
11 U.S. EPA. 2004. Wadeable Streams Assessment: field operations manual. EPA/841/B-04/004.
12 Washington, DC.
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INDICATOR: Nitrogen and Phosphorus in Wadeable Stre.
2 Nitrogen and phosphorus are essential elements in aquatic ecosystems. Both nutrients are used by plants
3 and algae for growth (U.S. EPA, 2005). Excess nutrients, however, can lead to increased algal production,
4 and excess nutrients in streams can also affect lakes, larger rivers, and coastal waters downstream. In
5 addition to being visually unappealing, excess algal growth can contribute to the loss of oxygen needed
6 by fish and other animals, which in turn can lead to altered biological assemblages. Sources of excess
7 nutrients include municipal sewage and septic tank drainfields, agricultural runoff, excess fertilizer
8 application, and atmospheric deposition of nitrogen (Herlihy et al., 1998).
9 This indicator measures total phosphorus and total nitrogen based on data collected for the U.S. EPA's
10 Wadeable Streams Assessment (WSA). Wadeable streams—streams, creeks, and small rivers that are
11 shallow enough to be sampled using methods that involve wading into the water—represent a vital
12 linkage between land and water. They typically include waters classified as 1st through 4th order in the
13 Strahler Stream Order classification system (Strahler, 1952). The WSA is based on a probabilistic design,
14 so the results from representative sample sites can be used to make a statistically valid statement about
15 nitrogen and phosphorus concentrations in all of the nation's wadeable streams.
16 Crews sampled 1,392 randomized sites across the United States using standardized methods. Western
17 sites were sampled between 2000 and 2004; eastern and central sites were sampled in 2004. All sites were
18 sampled between mid-April and mid-November. At each site, a water sample was collected at mid-depth
19 in the stream and analyzed following standard laboratory protocols (U.S. EPA, 2004a, 2004b).
20 Because naturally occurring nutrient levels vary from one geographic area to another, streams were
21 divided into nine ecoregions.3 In each ecoregion, a set of relatively undisturbed sites was sampled in order
22 to determine the range of nutrient concentrations that would be considered "low." Next, observed nitrogen
23 and phosphorus concentrations from all sites were compared to the distribution of concentrations among
24 the ecoregion's reference sites. If the observed result was above the 95th percentile of the ecoregion's
25 reference distribution, the concentration was labeled "high." This threshold was used because it offers a
26 high degree of confidence that the observed condition is statistically different from the condition of the
27 reference streams. Concentrations below the 75th percentile of the reference range were labeled "low,"
28 indicating a high probability that the site is similar to the relatively undisturbed reference sites.
29 Concentrations falling between the 75th and 95th percentiles were labeled "moderate."
3 For this analysis, the 48 contiguous states were divided into nine broad ecoregions. These "macro-level"
ecoregions were defined by the WSA based on groupings of EPA Level III ecoregions (for a map of EPA Level III
ecoregions, see http://www.epa.gov/wed/pages/ecoregions/level iii.htm). A map of the nine WSA ecoregions will
be available in the e-ROE.
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3-22
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1 What the Data Show
2 Nationwide, 43.3 percent of wadeable stream miles
3 had low total nitrogen concentrations, while high
4 nitrogen concentrations were found in 31.8 percent of
5 stream miles (Exhibit 3-6). The results for total
6 phosphorus are similar to those for nitrogen, with low
7 concentrations in 48.8 percent of stream miles and
8 high concentrations in 30.9 percent (Exhibit 3-6). The
9 concentrations associated with the regional thresholds
10 vary because of natural differences among the
11 ecoregions. Approximately 4 percent of the nation's
12 wadeable stream length could not be assessed because
13 of missing or inadequate sample data.
14 Indicator Limitations
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Exhibit 3-6. Nitrogen and phosphorus in
wadeable streams of the contiguous U.S.,
2000-2004"
100
80
H
'E
Percent of stream
ro ^ o>
0000
A. Total nitrogen B. Total phosphorus
4.2
.
43.3
20.7
31.8
4.2
.
48.8
16.1
30.9
Concentration:
D Not assessed/
no data
DLow
D Moderate
DHigh
"Compared with minimally disturbed reference sites. See text for
definitions of the categories shown in the figure.
Data source: U.S. EPA, Wadeable Streams Assessment
Samples were taken one time from each
sampling location during the index period
(April-November). Although the
probability sampling design results in an
unbiased estimate for total N and P
concentrations in wadeable streams during
the study period, concentrations may be
different during other seasons.
Trend data are unavailable because this is the first time that a survey on this broad scale has
been conducted, and the survey design does not allow trends to be calculated within a single
sampling period (2000-2004). These data will serve as a baseline for future surveys.
Not all forms of nitrogen and phosphorus are equally bioavailable, and the ratio of nitrogen
and phosphorus can affect the biomass and type of species of algae in streams. The forms of
N and P and the N/P ratios may vary somewhat between the regional reference sites and the
WSA streams.
30 Data Sources
31 Aggregate data for this indicator were provided by EPA's Wadeable Streams Assessment (WSA) (U.S.
32 EPA, 2006b). Data from individual stream sites can be obtained from EPA's STORET database (U.S.
33 EPA, 2006a) (http://www.epa. gov/owow/streamsurvey/web_data.html).
34 References
35 Herlihy, A.T., J.L. Stoddard, and C.B. Johnson. 1998. The relationship between stream chemistry and
36 watershed land use data in the Mid-Atlantic region. US Water Air Soil Pollut. 105:377-386.
37 Strahler, A.N. 1952. Dynamic basis of geomorphology. Geol. Soc. Am. Bull. 63:923-938.
38 U.S. EPA. 2006a. Data from the Wadeable Streams Assessment. Accessed 2006.
39
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1 U.S. EPA. 2006b. Wadeable Streams Assessment: a collaborative survey of the nation's streams. EPA
2 841-B-06-002. Washington, DC.
3
4 U.S. EPA. 2005. National estuary program—challenges facing our estuaries. Key management issues:
5 nutrient overlaoding.
6 U.S. EPA. 2004a. Wadeable Streams Assessment: field operations manual. EPA/841/B-04/004.
7 Washington, DC.
8 U.S. EPA. 2004b. Wadeable Streams Assessment: water chemistry laboratory manual. EPA/841/B-
9 04/008. Washington, DC.
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NDICATOR: Nitrogen and Phosphorus in Streams in Agricultural Watershi
2 Nitrogen is a critical nutrient that is generally used and reused by plants within natural ecosystems, with
3 minimal "leakage" into surface or ground water, where nitrogen concentrations remain very low
4 (Vitousek et al., 2002). When nitrogen is applied to the land in amounts greater than can be incorporated
5 into crops or lost to the atmosphere through volatilization or denitrification, however, nitrogen
6 concentrations in streams can increase. The major sources of excess nitrogen in predominantly
7 agricultural watersheds are fertilizer and animal waste; other sources include septic systems and
8 atmospheric deposition. The total nitrogen concentration in streams is comprised of the most common
9 bioavailable form (nitrate), organic nitrogen which is generally less available to biota, and nitrite and
10 ammonium compounds which are typically not present in streams except in highly polluted situations.
11 Excess nitrate is not toxic to aquatic life, but increased nitrogen may result in overgrowth of algae which
12 can decrease the dissolved oxygen content of the water, thereby harming or killing fish and other aquatic
13 species (U.S. EPA, 2005). Excess nitrogen also can lead to problems in downstream coastal waters, as
14 discussed further in the N and P Discharge from Large Rivers indicator (p. 3-28). High concentrations of
15 nitrate in drinking water may pose a risk of methemoglobinemia, a condition that interferes with oxygen
16 transport in the blood of infants (U.S. EPA, 2004).
17 Phosphorus also is an essential nutrient for all life forms, but at high concentrations the most biologically
18 active form of phosphorus (orthophosphate) can cause water quality problems by overstimulating the
19 growth of algae. In addition to being visually unappealing and causing tastes and odors in water supplies,
20 excess algal growth can contribute to the loss of oxygen needed by fish and other animals. Elevated levels
21 of phosphorus in streams can result from fertilizer use, animal wastes and wastewater, and the use of
22 phosphate detergents. The fraction of total phosphorus not in the orthophosphate form consists of organic
23 and mineral phosphorus fractions whose bioavailability varies widely.
24 This indicator reports nitrogen and phosphorus concentrations in stream water samples collected from
25 1992 to 2001 by the U.S. Geological Survey's National Water Quality Assessment (NAWQA) program,
26 which surveys the condition of streams and aquifers in study units throughout the contiguous United
27 States. Specifically, this indicator reflects the condition of streams draining 111 watersheds where
28 agriculture is the predominant land use, according to criteria outlined in Mueller and Spahr (2005), and
29 where data are available to characterize all four species of interest (nitrate, total nitrogen, orthophosphate,
30 and total phosphorus). These 111 watersheds are located in 38 of the 51 NAWQA study units (i.e., major
31 river basins). Sites were chosen to avoid large point sources of nutrients (e.g., wastewater treatment
32 plants). At each stream site, samples were collected 12 to 25 times each year over a l-to-3-year period;
33 this indicator is based on a flow-weighted annual average of those samples. Related indicators report the
34 concentrations of nitrogen and phosphorus in small wadeable streams, regardless of land use (p. 3-22),
35 and nitrate concentrations in ground water in agricultural watersheds (p. 3-44).
36 For nitrogen, the indicator reports the percentage of streams with average concentrations of nitrate and
37 total nitrogen in one of five ranges: less than 1 milligram per liter (mg/L); 1-2 mg/L; 2-6 mg/L; 6-10
38 mg/L; and 10 mg/L or more. (This indicator measures nitrate (as N), i.e., the fraction of the material that
39 is actually nitrogen.) The highest level (10 mg/L as N) represents the Maximum Contaminant Level
40 (MCL) for nitrate allowed in finished drinking water in the United States (U.S. EPA, 2006). Because
41 people are unlikely to drink untreated stream water, this concentration should be viewed as a point of
42 reference, and not necessarily as a health risk to consumers. There is no human health guideline for total
43 nitrogen and no comparable aquatic health guideline for either nitrate or total nitrogen because neither
44 form represents a direct threat to organisms living in the stream.
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1 Concentrations of total phosphorus and
2 orthophosphate (as P) are reported in four ranges: less
3 than 0.1 mg/L, 0.1-0.3 mg/L, 0.3-0.5 mg/L, and 0.5
4 mg/L or more. There is currently no national water
5 quality criterion for either form to protect surface
6 waters because the effects of phosphorus vary by
7 region and are dependent on physical factors such as
8 the size, hydrology, and depth of rivers and lakes.
9 What the Data Show
10 Average flow-weighted nitrate concentrations were
11 above 2 mg/L in about half of the stream sites in these
12 predominantly agricultural watersheds (Exhibit 3-7).
13 About 12 percent of stream sites had nitrate
14 concentrations above the federal drinking water MCL
15 of 10 mg/L (the slightly smaller percentage of streams
16 with total N above 10 mg/L is an artifact of the flow-
17 weighting algorithm). Nearly half of the streams
18 sampled had total nitrogen concentrations in the 2-6
19 mg/L range, and 72 percent had concentrations above
20 2 mg/L.
21 Almost 60 percent of the streams in agricultural
22 watersheds had flow-weighted concentrations of
23 orthophosphate (as P) of less than 0.1 mg/L. More than
24 three-fourths of the streams had average annual flow-
25 weighted concentrations of total phosphorus above 0.1
26 mg/L, while nearly 15 percent had total phosphorus
27 concentrations above 0.5 mg/L (Exhibit 3-8).
28 Indicator Limitations
29
30
31
32
33
34
35
36
37
38
39
40
These data represent streams draining
agricultural watersheds in 38 of the major
river basins (study units) sampled by the
NAWQA program in the contiguous U.S.
While they were chosen to be
representative of agricultural watersheds
across the United States, they are the
result of a targeted sample design, and
may not be an accurate reflection of the
distribution of concentrations in all
streams in agricultural watersheds in the
U.S.
Exhibit 3-7. Nitrogen in streams in agricultural
watersheds of the contiguous U.S., 1992-2001"
100
80
60
!40
20
A. Nitrate (as N) B. Total nitrogen
27.0
19.8
34.2
7.2
11.7
8.1
19.8
44.1
17 1
10.8
Concentration:
D Less than
1 mg/L
D1to2
mg/L
D2to6
mg/L
D6to10
mg/L
D 10 mg/L
"Coverage: 111 watersheds in which agriculture is the
predominant land use, according to criteria outlined in Mueller
and Spahr, 2005. These watersheds are within 38 major river
basins studied by the USGS NAWQA Program.
Data source: Mueller and Spahr, 2005
Exhibit 3-8. Phosphorus in streams in
agricultural watersheds of the contiguous U.S.,
1992-2001a
100
80
60
40
20
A. Orthophosphate B. Total phosphorus
(asP)
2.7-
59.5
36.0
21.6
45.9
18.0
14.4
Concentration:
D Less than
0.1 mg/L
• 0.1 to 0.3
mg/L
D 0.3 to 0.5
mg/L
D 0.5 mg/L
or more
"Coverage: 111 watersheds in which agriculture is the
predominant land use, according to criteria outlined in Mueller
and Spahr, 2005. These watersheds are within 38 major river
basins studied by the USGS NAWQA Program.
Data source: Mueller and Spahr, 2005
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1 * This indicator does not provide information about trends over time, as the NAWQA program
2 has completed only one full sampling cycle to date. Completion of the next round of
3 sampling will allow trend analysis, using the data presented here as a baseline.
4 • Drinking water treatment can significantly reduce concentrations of nitrate, so the levels of
5 contaminants reported in this indicator are not necessarily representative of the exposures to
6 people when these waters are used as public drinking water supplies.
7 Data Sources
8 Summary data for this indicator were provided by the U.S. Geological Survey's National Water Quality
9 Assessment (NAWQA) program. These data have been published in Mueller and Spahr (2005), along
10 with the individual sampling results on which the analysis is based.
11 References
12 Mueller, O.K., and N.E. Spahr. 2005. Water-quality, streamflow, and ancillary data for nutrients in
13 streams and rivers across the nation, 1992-2001: U.S. Geological Survey data series 152.
14
15 U.S. EPA. 2005. National estuary program—challenges facing our estuaries. Key management issues:
16 nutrient overloading,
17 U.S.EPA. 2006. List of drinking water contaminants and MCLs.
18
19 U.S. EPA. 2004. Consumer factsheet on nitrates/nitrites.
20
21 Vitousek, P., H. Mooney, L. Olander, and S. Allison. 2002. Nitrogen and nature. Ambio 31:97-101.
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NDICATOR: Nitrogen and Phosphorus Discharge from Large River
2 Nitrogen is a critical nutrient for plants and animals, and terrestrial ecosystems and headwater streams
3 have a considerable ability to capture nitrogen or to reduce it to N2 gas though the process of
4 denitrification. Nitrogen cycling and retention is thus one of the most important functions of ecosystems
5 (Vitousek et al., 2002). When loads of nitrogen from fertilizer, septic tanks, and atmospheric deposition
6 exceed the capacity of terrestrial systems (including croplands), the excess may enter surface waters,
7 where it may have "cascading" harmful effects as it moves downstream to coastal ecosystems (Galloway
8 and Cowling, 2002). Other sources of excess nitrogen include direct discharges from storm water or
9 treated wastewater. This indicator specifically focuses on nitrate, which is one of the most bioavailable
10 forms of nitrogen in bodies of water.
11 Phosphorus is a critical nutrient for all forms of life, but like nitrogen, phosphorus that enters the
12 environment from anthropogenic sources may exceed the needs and capacity of the terrestrial ecosystem.
13 As a result, excess phosphorus may enter lakes and streams. Because phosphorus is often the limiting
14 nutrient in these bodies of water, an excess may contribute to unsightly algal blooms, which cause taste
15 and odor problems and deplete oxygen needed by fish and other aquatic species. In some cases, excess
16 phosphorus can combine with excess nitrogen to exacerbate algal blooms (i.e., in situations where algal
17 growth is co-limited by both nutrients), although excess nitrogen usually has a larger effect downstream
18 in coastal waters. The most common sources of phosphorus in rivers are fertilizer and wastewater,
19 including storm water and treated wastewater discharged directly into the river. In most watersheds, the
20 atmosphere is not an important source or sink for phosphorus.
21 This indicator tracks trends in the discharge of nitrate and phosphorus from four of the largest rivers in the
22 United States: the Mississippi, Columbia, St. Lawrence, and Susquehanna. While not inclusive of the
23 entire nation, these four rivers account for approximately 55 percent of all freshwater flow entering the
24 ocean from the contiguous 48 states, and are geographically distributed. This indicator relies on stream
25 flow and water-quality data collected by the U.S. Geological Survey (USGS), which has monitored
26 nutrient export from the Mississippi River since the mid-1950s and from the Susquehanna, St. Lawrence,
27 and Columbia Rivers since the 1970s. Data were collected near the mouth of each river except the St.
28 Lawrence, which was sampled near the point where it leaves the United States.
29 At the sites for which data are included in this indicator, USGS recorded daily stream levels and
30 volumetric discharge using permanent stream gauges. Water quality samples were collected at least
31 quarterly over the period of interest, in some cases up to 15 times per year. USGS calculated annual
32 nitrogen load from these data using regression models relating nitrogen concentration to discharge, day-
33 of-year (to capture seasonal effects), and time (to capture any trend over the period). These models were
34 used to make daily estimates of concentrations, which were multiplied by the daily flow to calculate the
35 daily nutrient load (Heinz Center, 2005). Because data on forms of nitrogen other than nitrate and nitrite
36 are not as prevalent in the historical record, this indicator only uses measurements of nitrate plus nitrite.
37 As nitrite concentrations are typically very small relative to nitrate, this mixture is simply referred to as
38 nitrate.
39 What the Data Show
40 The Mississippi River, which drains more than 40 percent of the area of the lower 48 states, carries
41 roughly 15 times more nitrate than any other U.S. river. Nitrate discharge from the Mississippi increased
42 noticeably over much of the last half-century, rising from 200,000-500,000 tons per year in the 1950s and
43 1960s to an average of about 1,000,000 tons per year during the 1980s and 1990s (Exhibit 3-9). Large
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Exhibit 3-9. Nitrate discharge from four major
U.S. rivers, 1955-2003"
2,500
1950 1960 1970 1980 1990 2000 2010
Year
M50
MOO
& 50
Detail
1970 1980 1990 2000 2010
Year
aMost measurements include nitrate
plus nitrite, but because
concentrations of nitrite are typically
insignificant relative to nitrate, this
mixture is simply called "nitrate."
Data source: USGS National Water
Quality Assessment (NAWQA)
Program, USGS National Stream
Quality Network (NASQAN), andUSGS
Federal-State Cooperative Program
Areas drained by these
four rivers
Columbia
St. Lawrence
Mississippi
Susquehanna
year-to-year fluctuations are also evident. The
Mississippi drains the agricultural center of the nation
and contains a large percentage of the growing
population, so it may not be surprising that the
watershed has not been able to assimilate all the
nitrogen from sources such as crop and lawn
applications, animal manure and human wastes, and
atmospheric deposition (e.g., Rabalais and Turner,
2001).
The nitrate load in the Columbia River increased to
almost twice its historical loads during the later half
of the 1990s, but by the last year of record (2002), the
amount of nitrate discharged had returned to levels
similar to those seen in the late 1970s (Exhibit 3-9).
The St. Lawrence River showed an overall upward
trend in nitrate discharge over the period of record,
while the Susquehanna does not appear to have shown
an appreciable trend in either direction. Over the
period of record, the Columbia and St. Lawrence both
carried an average of about 66,000 tons of nitrate per
year, while the Susquehanna averaged 46,000 tons.
By comparison, the Mississippi carried an average of
770,000 tons per year over its period of record.
The amount of phosphorus discharged decreased in
the St. Lawrence and Susquehanna Rivers over the
period of record (Exhibit 3-10). There is no obvious
trend in the Mississippi and Columbia Rivers, and the
year-to-year variability is quite large. Nitrogen and
phosphorus discharges tend to be substantially higher
during years of high precipitation, because of
increased erosion and transport of the nutrients to
stream channels (Smith et al., 2003). Over the full
period of record, average annual phosphorus loads for
the Mississippi, Columbia, St. Lawrence, and
Susquehanna were 136,000; 11,000; 6,000; and 3,000
tons, respectively.
Indicator Limitations
38
39
40
41
42
43
44
45
The indicator does not include data from numerous coastal watersheds whose human
populations are rapidly increasing (e.g., Valigura et al., 2000).
It does not include smaller watersheds in geologically sensitive areas, whose ability to retain
nitrogen might be affected by acid deposition (e.g., Evans et al., 2000).
It does not include forms of nitrogen other than nitrate. Although nitrate is one of the most
bioavailable forms of nitrogen, other forms may constitute a substantial portion of the
nitrogen load. Historically, nitrate data are more extensive than data on other forms of
nitrogen.
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5
6
7
8
9
10
11
• Not all forms of phosphorus included in
the total phosphorus loads are equally
capable of causing algal blooms.
Data Sources
A previous version of this analysis was published in
the Heinz Center's report, The State of the Nation's
Ecosystems (Heinz Center, 2005). Updated data were
provided to EPA by USGS. USGS's analysis was
based on nutrient sampling and daily stream flow data,
which can be obtained from USGS's public databases
(USGS, 2006a, 2006b).
12 References
13 Evans, C.D., A. Jenkins, and R.F. Wright. 2000.
14 Surface water acidification in the South Pennines I.
15 Current status and spatial variability. Environ. Pollut.
16 109(1): 11-20.
Exhibit 3-10. Total phosphorus discharge from
four major U.S. rivers, 1971-2003
1970
2010
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Galloway, J., and E. Cowling. 2002. Reactive nitrogen
and the world: 200 years of change. Ambio 31:64-71.
The H. John Heinz III Center for Science, Economics,
and the Environment. 2005. The state of the nation's
ecosystems: measuring the lands, waters, and living
resources of the United States. New York, NY:
Cambridge University Press, September 2002. Web
update 2005:
Rabalais, N.N., and R.E. Turner, eds. 2001. Coastal
hypoxia: consequences for living resources and
ecosystems. Coastal and estuarine studies 58.
Washington, DC: American Geophysical Union.
Smith, S.V., D.P. Swaney, L. Talaue-McManus, J.D.
Bartley, P.T. Sandhei, C.J. McLaughlin, V.C. Dupra,
C.J. Grassland, R.W. Buddemeier, B.A. Maxwell, and
F. Wulff. 2003. Humans, hydrology, and the
distribution of inorganic nutrient loading to the ocean
BioScience 53:235-245.
USGS. 2006a. National Stream Quality Accounting
Network (NASQAN) data. Accessed 2006.
USGS. 2006b. National water information system.
Accessed 2006.
8
-a
25
20
15
10
& 5
«
Detail
1970
1980
1990
2000
2010
Areas drained by these
four rivers
Columbia
St. Lawrence
Mississippi
Susquehanna
Data source: USGS National Water Quality Assessment (NAWQA) Program,
USGS National Stream Quality Network (NASQAN), and USGS Federal-State
Cooperative Program
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1 Valigura, R., R. Alexander, M. Castro, T. Meyers, H. Paerl, P. Stacey, and R. Turner, eds. 2000. Nitrogen
2 loading in coastal water bodies—an atmospheric perspective. Washington, DC: American Geophysical
3 Union.
4 Vitousek, P., H. Mooney, L. Olander, and S. Allison. 2002. Nitrogen and nature. Ambio 31:97-101.
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INDICATOR: Pesticides in Streams in Agricultural Watersheds
2 Pesticides are chemicals or biological agents that kill plant or animal pests and may include herbicides,
3 insecticides, fungicides, and rodenticides. More than one billion pounds of pesticides (measured as
4 pounds of active ingredient) are used in the United States each year to control weeds, insects, and other
5 organisms that threaten or undermine human activities (Aspelin, 2003). About 80 percent of the total is
6 used for agricultural purposes. Although pesticide use has resulted in increased crop production and other
7 benefits, pesticide contamination of streams, rivers, lakes, reservoirs, coastal areas, and ground water can
8 cause unintended adverse effects on aquatic life, recreation, drinking water, irrigation, and other uses.
9 Water also is one of the primary pathways by which pesticides are transported from their application areas
10 to other parts of the environment (USGS, 2000).
11 This indicator is based on stream water samples collected between 1992 and 2001 as part of the U.S.
12 Geological Survey's National Water Quality Assessment (NAWQA) program, which surveys the
13 condition of streams and aquifers in study units throughout the contiguous United States. Of the streams
14 sampled for pesticides, this indicator focuses on 83 streams in watersheds where agriculture represents the
15 predominant land use, according to criteria outlined in Gilliom et al. (2006). These 83 streams are located
16 in 36 of the 51 NAWQA study units (i.e., major river basins). From each site, NAWQA collected 10 to 49
17 stream water samples per year over a l-to-3-year period to analyze for 75 different pesticides and 8
18 pesticide degradation products, which together account for approximately 78 percent of the total
19 agricultural pesticide application in the United States by weight during the study period (Gilliom et al.,
20 2006). This indicator reports the number of stream sites where the annual time-weighted average
21 concentration of one or more of these pesticides or degradation products exceeds standards for aquatic or
22 human health. A related indicator discusses pesticide concentrations in ground water in agricultural
23 watersheds (p. 3-44).
24 Three types of U.S. EPA standards and guidelines for drinking water were used as human health
25 benchmarks for pesticide concentrations: Maximum Contaminant Levels (MCLs), Cancer Risk
26 Concentrations (CRCs), and Lifetime Health Advisories (HA-Ls). All of these standards/guidelines are
27 concentrations that pertain to lifetime exposure through drinking water (CRCs relate to potential
28 carcinogens and HA-Ls relate to non-carcinogenic adverse health effects). Gilliom et al. (2006) provides a
29 full list of the standards and guidelines used in this assessment; see also the list of MCLs at EPA (2006).
30 More detail on these types of benchmarks, their derivation, and their underlying assumptions is provided
31 in Nowell and Resek (1994). If a chemical had multiple benchmarks, the MCL was used if available;
32 otherwise, the lower of the CRC (at 1 in 1,000,000 cancer risk) and HA-L values was selected. An
33 exceedance was identified if a yearly, time-weighted mean concentration exceeded the corresponding
34 standard or guideline (Gilliom et al., 2006).
35 Several types of water quality benchmarks were used for aquatic life. Where available, data were
36 compared with EPA's acute and chronic ambient water-quality criteria for the protection of aquatic life
37 (AWQC-ALs). The acute AWQC-AL is the highest concentration of a chemical to which an aquatic
38 community can be exposed briefly without resulting in an unacceptable effect. The chronic AWQC-AL is
39 the highest concentration to which an aquatic community can be exposed indefinitely without resulting in
40 an unacceptable effect. An exceedance was identified if a single sample exceeded the acute AWQC-AL or
41 if a 4-day moving average exceeded the chronic AWQC-AL (per EPA's definition of the chronic AWQC-
42 AL). Results were also compared with aquatic life benchmarks derived from toxicity values presented in
43 registration and risk-assessment documents developed by EPA's Office of Pesticide Programs (OPP).
44 These benchmarks included acute and chronic values for fish and invertebrates, acute values for vascular
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23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
Exhibit 3-11. Pesticides in streams in
agricultural watersheds of the contiguous U.S.,
1992-2001a
A. Aquatic life
benchmarks
B. Human health
benchmarks'1
1 and nonvascular plants, and a value for aquatic community effects. An exceedance was identified if a
2 single sample exceeded any acute benchmark or if the relevant moving average exceeded a chronic
3 benchmark. More information about the derivation and application of aquatic life guidelines for this
4 indicator can be found in Gilliom et al. (2006).
What the Data Show
6 In 57 percent of the streams sampled, at least one
7 pesticide was detected at a concentration that exceeded
8 one or more aquatic life benchmarks (Exhibit 3-11).
9 Roughly 10 percent of streams contained at least one
10 pesticide at a concentration above the corresponding
11 benchmark for human health. For reference, NAWQA
12 data indicate that within this set of agricultural
13 streams, at least one pesticide was present at detectable
14 levels more than 90 percent of the time (Gilliom et al.,
15 2006). NAWQA data also indicate that pesticides in
16 agricultural streams most often occur in mixtures (i.e.,
17 more than one compound is present in the sample)
18 (Gilliom et al., 2006). The human health and
19 environmental impacts of pesticide contamination,
20 particularly when the pesticides occur as mixtures, are
21 not well understood.
100
80
60
40
20
22 Indicator Limitations
43.4
22.9
21.7
12.0
90.4
— '
7.2
1 A
Number of
benchmarks
exceeded:
DO
• 1
D2or3
D 4 or more
Coverage: 83 watersheds in which agriculture is the predominant
land use, according to criteria outlined in Gilliom et al., 2006.
These watersheds are within 36 major river basins studied by the
USGS NAWQA program.
bNo streams exceeded 4 or more human health benchmarks.
Data source: USGS, National Water Quality Assessment
(NAWQA) Program
These data represent streams draining
agricultural watersheds in 36 of the study
units (major river basins) sampled by the
NAWQA program in the contiguous
United States. While they were chosen to
be representative of agricultural
watersheds across the nation, they are the
result of a targeted sampling design, and
may not be an accurate reflection of the
distribution of concentrations in all
streams in the nation's agricultural watersheds
This indicator does not provide information about trends over time, as the NAWQA program
has completed only one full sampling cycle to date. Completion of the next round of
sampling will allow trend analysis, using the data presented here as a baseline.
Drinking water treatment can significantly reduce concentrations of many pesticides, so the
levels reported in this indicator are not necessarily representative of the exposures to people
when these waters are used as public drinking water supplies.
Aquatic life benchmarks do not currently exist for 21 of the 83 pesticides and pesticide
degradation products analyzed, while drinking water standards or guidelines (MCLs, CRCs,
and HAs) do not exist for 36 of 83. Current standards and guidelines do not account for
mixtures of pesticide chemicals and seasonal pulses of high concentrations. Possible pesticide
effects on reproductive, nervous, and immune systems, as well as on chemically sensitive
individuals, are not yet well understood.
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1 • The pesticide benchmarks used here are designed to be fully protective of human or aquatic
2 health. Other indicators, such as Coastal Sediment Quality (p. 3-67), use aquatic life
3 thresholds that are less protective. Thus, these indicators are not necessarily comparable to
4 one another.
5 • This indicator does not provide information on the degree to which pesticide concentrations
6 exceed or fall below benchmarks.
7 Data Sources
8 Summary data for this indicator were provided by the U.S. Geological Survey's National Water Quality
9 Assessment (NAWQA) program. Portions of this analysis have also been published in Gilliom et al.
10 (2006). Data from individual sample sites are available online in Appendix 6 of the same report
11 (http://ca.water.usgs.gov/pnsp/pubs/circl291/appendix6/).
12 References
13 Aspelin, A.L. 2003. Pesticide usage in the United States: trends during the 20th century. Raleigh, NC:
14 Center for Integrated Pest Management, North Carolina State University.
15
16 Gilliom, R.J., J.E. Barbash, C.G. Crawford, P.A. Hamilton, J.D. Martin, N. Nakagaki, L.H. Nowell, J.C.
17 Scott, P.E. Stackelberg, G.P. Thelin, and D.M. Wolock. 2006. Pesticides in the Nation's Streams and
18 Ground Water, 1992-2001: U.S. Geological Survey circular 1291.
19
20 Nowell, L.H., and E.A. Resek. 1994. National standards and guidelines for pesticides in water, sediment,
21 and aquatic organisms: application to water-quality assessments: Rev. Environ. Contam. Toxicol. 140:1-
22 164.
23 U.S. EPA. 2006. List of drinking water contaminants and MCLs.
24
25 USGS (U.S. Geological Survey). 2000. Pesticides in stream sediment and aquatic biota.
26
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NDICATOR: Benthic Macroinvertebrates in Wadeable Strea
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Freshwater benthic macroinvertebrate communities are composed primarily of insect larvae, mollusks,
and worms. They are an essential link in the aquatic food web, providing food for fish and consuming
algae and aquatic vegetation (Karr and Dudley, 1997). The presence and distribution of
macroinvertebrates in streams can vary across geographic locations based on elevation, stream gradient,
and substrate (Barbour et al., 1999). These organisms are sensitive to disturbances in stream chemistry
and physical habitat, both in the stream channel and along the riparian zone, and alterations to the
physical habitat or water chemistry of the stream can have direct and indirect impacts on their community
structure. Because of their relatively long life cycles (approximately one year) and limited migration,
benthic macroinvertebrates are particularly susceptible to site-specific stressors (Barbour et al., 1999).
This indicator is based on data collected for the U.S. EPA's Wadeable Streams Assessment (WSA).
Wadeable streams are streams, creeks, and small rivers that are shallow enough to be sampled using
methods that involve wading into the water. They typically include waters classified as 1st through 4th
order in the Strahler Stream Order classification system (Strahler, 1952). Between 2000 and 2004, crews
sampled 1,392 sites throughout the contiguous United States using standardized methods (U.S. EPA,
2004a, 2004b). Sites were sampled between mid-April and mid-November. At each site, a composite
bottom sample was collected from eleven equally spaced transects within the sample reach. The WSA is
based on a probabilistic design, so results from the sample sites can be used to make statistically valid
statements about the percentage of wadeable stream miles that fall above or below reference values for
the indicator. Benthic community condition was determined using two different approaches, each
reflecting a distinct aspect of the indicator: an Index of Biological Integrity (IBI) and an
Observed/Expected (O/E) predictive model.
The IBI is an index that reduces complex information about community structure into a simple numerical
value based on measures of taxonomic richness (number of taxa); taxonomic composition (e.g., insects vs.
non-insects); taxonomic diversity; feeding groups (e.g., shredders, scrapers, or predators); habits (e.g.,
burrowing, clinging, or climbing taxa); and tolerance to stressors. Separate metrics were used for each of
these categories in different ecoregions of the United States, based on their ability to best discriminate
among streams.4 Each metric was scaled against the 5th-95th percentiles for the streams in each region to
create an overall IBI, whose value ranges from 0 to 100 (Stoddard et al., 2005).
Once the overall IBI was established, a set of relatively undisturbed sites was selected in order to
determine the range of IBI scores that would be expected among "least disturbed" sites. A separate
reference distribution was developed for each ecoregion. Next, the IBI score for every sampled site was
compared to the distribution of IBI scores among the ecoregion's reference sites. If a site's IBI score was
below the 5th percentile of the regional reference distribution, the site was classified as "most disturbed."
This threshold was used because it offers a high degree of confidence that the observed condition is
statistically different from the "least disturbed" reference condition. Streams with an IBI score above the
25th percentile of the reference range were labeled "least disturbed," indicating a high probability that the
4 For this analysis, the 48 contiguous states were divided into nine broad ecoregions. These "macro-level"
ecoregions were defined by the WSA based on groupings of EPA Level III ecoregions (for a map of EPA Level III
ecoregions, see http://www.epa.gov/wed/pages/ecoregions/level __iii.htm). A map of the nine WSA ecoregions will
be available in the e-ROE.
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3-35
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Exhibit 3-12. Index of Biological Integrity (IBI) for
benthic macroinvertebrates in wadeable streams
of the contiguous U.S., by ecoregion, 2000-20043
IBI score:
Least
disturbed
Moderately
disturbed
Most
disturbed
Not assessed/
no data
Percent of stream miles in each category:
Eastern
Highlands
Plains and
Lowlands
West
All U.S.
18.2
20.4 51.8 9.5
29.0
29.0 40.0
45.1 25.9 27.4
28.2
24.9 41.9
2.0
1.7
5.0
aEcoregions based on Omernik,
1987.
Data source: U.S. EPA,
Wadeable Streams Assessment
Ecoregions
•» Jf
Kj'
~~~*~ Eastern
West "W*1" Highlands
Plains and Lowlands
Exhibit 3-13. Percent loss of benthic
macroinvertebrate taxa in wadeable streams of
the contiguous U.S., relative to the number of
expected taxa, 2000-2004"
-------
1 (Exhibit 3-13). Nearly 40 percent (38.6 percent) of wadeable stream miles in this area have lost more than
2 20 percent of their macroinvertebrate taxa, compared to comparable minimally disturbed reference sites,
3 and 8.3 percent of stream miles have lost more than 60 percent of their macroinvertebrate taxa.
4 Indicator Limitations
5 • Although the probability sampling design results in unbiased estimates for the IBI and O/E in
6 wadeable streams during the April-November index period, values may be different during
7 other seasons.
8 • Reference conditions for the IBI and O/E vary from one ecoregion to another in both number
9 and quality, which limits the degree of ecoregional resolution at which this indicator can be
10 calculated.
11 • Because "E" is subject to both model error and sampling error, O/E values near 1.0 (above or
12 below) do not necessarily imply a gain or loss of species relative to the reference conditions.
13 • Trend data are unavailable because this is the first time that a survey on this broad scale has
14 been conducted, and the survey design does not allow trends to be calculated within a single
15 sampling period (2000-2004). These data will serve as a baseline for future surveys.
16 Data Sources
17 The results shown in Exhibit 3-12 were previously published in EPA's 2006 Wadeable Streams
18 Assessment (WSA) report (U.S. EPA, 2006c). The data in Exhibit 3-13 are based on frequency
19 distributions provided by the WSA program (the 2006 report also presents results from the O/E analysis,
20 but using different categories). Data from individual stream sites can be obtained from EPA's STORET
21 database (U.S. EPA. 2006a) (http://www.epa.gov/owow/streamsurvev/web data.html).
22 Ecoregions for the IBI metric are WSA "Mega Regions" based on groupings of EPA Level III Ecoregions
23 (Omernik, 1987; U.S. EPA, 2006b).
24 References
25 Armitage, D. 1987. The prediction of the macroinvertebrate fauna of unpolluted running-water sites in
26 Great Britain using environmental data. Freshwater Biol. 17:41-52.
27 Barbour, M.T., J. Gerritson, B.D. Snyder, and J.B. Stribling. 1999. Rapid bioassessment protocols for use
28 in streams and wadeable rivers: periphyton, benthic macroinvertebrates and fish. Second edition.
29 EPA/841/B-99/002. Washington, DC: U.S. Environmental Protection Agency.
30 Hawkins, C.P., and D.M. Carlisle. 2001. Use of predictive models for assessing the biological integrity of
31 wetlands and other aquatic habitats. In: Rader, R.B., and D.P. Batzer, eds. Bioassessment and
32 management of North American wetlands. New York, NY: John Wiley & Sons. pp. 59-83.
33 Hawkins, C.P., R.H. Norris, J.N. Hogue, and J.W. Feminella. 2000. Development and evaluation of
34 predictive models for measuring the biological integrity of streams. Ecol. Appl. 10:1456-1477.
35 Karr, J.R., and D.R. Dudley. 1981. Ecological perspective on water quality goals. Environ. Manage. 5:55-
36 68.
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1 Omernik, J.M. 1987. Ecoregions of the conterminous United States. Map (scale 1:7,500,000). Annals of
2 the Association of American Geographers 77(1): 118-125.
3 Stoddard, J., D.V. Peck, S.G. Paulsen, J. Van Sickle, C.P. Hawkins, A.T. Herlihy, R.M. Hughes, F.
4 Wright, P.R. Kaufmann, D.P. Larsen, G. Lomnicky, A.R. Olsen, S.A. Peterson, P.L. Ringold, and T.R.
5 Whittier. 2005. An ecological assessment of western streams and rivers. EPA/620/R-05/005. Washington,
6 DC: U.S. Environmental Protection Agency.
7
8 Strahler, A.N. 1952. Dynamic basis of geomorphology. Geol. Soc. Am. Bull. 63:923-938.
9 U.S. EPA. 2006a. Data from the Wadeable Streams Assessment. Accessed 2006.
10
11 U.S. EPA. 2006b. Level III ecoregions. Updated August 15, 2006.
12
13 U.S. EPA. 2006c. Wadeable Streams Assessment: a collaborative survey of the nation's streams. EPA
14 841-B-06-002. Washington, DC.
15
16 U.S. EPA. 2004a. Wadeable streams assessment: benthic laboratory methods. EPA/841/B-04/007.
17 Washington, DC.
18 U.S. EPA. 2004b. Wadeable streams assessment: field operations manual. EPA/84l/B-04/004.
19 Washington, DC.
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1 3.2.3 Discussion
2 What These Indicators Say About Trends in the Extent and Condition of
3 Fresh Surface Waters and Their Effects on Human Health and the
4 Environment
5 Although the indicators do not characterize the extent of all fresh surface waters, they do provide
6 information about flow patterns in streams (Stream Flows indicator, p. 3-14). As this indicator shows,
7 substantial shifts in the extent and timing of high and low flows can occur from one decade to the next.
8 These shifts are particularly important in intermittent streams, where life forms may be quite sensitive to
9 changes in patterns of flow and no flow. Although intermittent streams can be found throughout the
10 country, the Streams Flows indicator focuses on those that occur in grassland and shrubland areas, many
11 of which are arid or semi-arid and thus especially sensitive to water stress. As this indicator shows, flows
12 have generally increased over the last few decades, at least on a nationwide basis.
13 The physical condition of lakes and streams is in part a function of the interaction between sediment and
14 water. As the Streambed Stability indicator (p. 3-19) shows, about one-fourth of the nation's wadeable
15 streams show significant evidence of excess fine sediments, which can diminish habitat. In some cases,
16 excess sedimentation can reflect the influence of human stressors like erosion. Excess sedimentation also
17 can be a symptom of broader changes in physical condition, such as hydromodifications that alter flow
18 and sediment transport.
19 The ROE indicators provide a mixed picture of the chemical condition of fresh surface waters. Acidity in
20 lakes and streams is decreasing in some sensitive areas but holding steady in others (Lake and Stream
21 Acidity indicator, p. 2-62), while excess nutrients are present in many streams, ranging from small
22 wadeable streams to the nation's largest rivers (three N and P indicators, pp. 3-22, 3-25, and 3-28). In
23 agricultural areas, a large percentage of monitoring sites have at least one pesticide at levels that exceed
24 guidelines for aquatic health (Pesticides in Agricultural Streams indicator, p. 3-32). These indicators
25 reflect the influence of many stressors. For example, the two Agricultural Streams indicators (pp. 3-25
26 and 3-32) demonstrate how chemicals applied to the land can ultimately affect surface waters.
27 Conversely, efforts to reduce human stressors can result in improved water condition. For example, areas
28 with declines in acidity correspond with areas of decreased acid deposition (Lake and Stream Acidity
29 indicator, p. 2-62), while declining phosphorus loads in at least one river may be related to detergent bans
30 and improved sewage treatment (N and P Discharge from Large Rivers indicator, p. 3-28). The indicators
31 also reveal the influence of natural stressors, such as the role of precipitation in year-to-year variability in
32 nutrient loads.
33 The ROE indicators also provide a mixed picture of the biological condition of fresh surface waters. The
34 indicators of extent and physical and chemical condition show a number of attributes that could
35 potentially harm aquatic life, including substantial changes in high and low stream flows, a portion of
36 streams with excess sedimentation, pesticides above aquatic life guidelines, and nutrients at levels that
37 could encourage eutrophication. Benthic macroinvertebrate communities are particularly sensitive to
38 these stressors, and thus the condition of these assemblages can provide information about the extent to
39 which these stressors are causing measurable harm. About 40 percent of the nation's wadeable stream
40 miles exhibit a substantial loss (>20 percent) of macroinvertebrate taxa—approximately equal to the
41 number of stream miles considered "most disturbed" when other metrics of benthic community condition
42 are considered (Benthic Macroinvertebrates in Wadeable Streams indicator, p. 3-35).
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l Limitations, Gaps, and Challenges
2 Although the ROE indicators provide valuable information about the extent and condition of fresh surface
3 waters, there are a few general limitations to their ability to depict trends over space and time. For
4 example, trends in condition may be tied to the location and timing of intermittent stressors (e.g.,
5 pesticide application), so indicators that assess national condition using samples that are spread out over
6 time and space may obscure local conditions and extreme events. Some indicators are also restricted to
7 specific study areas. For example, the two Agricultural Streams indicators (pp. 3-25 and 3-32) do not
8 characterize non-agricultural watersheds, and the Lake and Stream Acidity indicator (p. 2-62) does not
9 include localized acidification in the West.
10 In addition to the challenges inherent in assessing fresh surface waters, there are also challenges in
11 interpreting what the indicators say. Ecological responses to freshwater stressors are complex and may
12 depend on the species that inhabit a particular area. In some cases—e.g., the three indicators from the
13 Wadeable Streams Assessment—data must be adjusted to account for variations in regional reference
14 conditions. It can also be difficult to link effects to specific stressors, as many indicators reflect the
15 interplay of multiple human and natural factors. For example, local bedrock can contribute high levels of
16 nutrients to some rivers, while precipitation variability can drive trends in nutrient discharge, potentially
17 obscuring trends in anthropogenic stressors.
18 There are no ROE indicators for a few key aspects of the extent and condition of fresh surface waters. The
19 following information would help to better answer this question:
20 • Information on the extent of different types of fresh surface waters, stressors to extent (e.g.,
21 water usage), and associated effects on ecological systems.
22 • Nationally consistent information to characterize stressors to fresh surface water condition—
23 specifically pollutant loadings from point and nonpoint sources.
24 • Information on the condition of large rivers. The N and P Discharge from Large Rivers
25 indicator (p. 3-28) describes nutrient loads at the mouth, but does not address conditions
26 upstream.
27 • Information on the condition of lakes. A nationally consistent indicator of lake trophic state
28 could bring together several aspects of condition (e.g., physical, chemical, and biological
29 parameters) related to eutrophication—a problem facing many of the nation's lakes.
30 • Information about toxic contaminants in freshwater sediments. Sediment contaminants can
31 accumulate through the food web, and may ultimately impact the health of humans who
32 consume fish and shellfish.
33 • Information on the condition offish communities, which can be affected by many different
34 stressors.
35 In addition, there are currently no ROE indicators that explicitly link human health effects to the extent or
36 condition of fresh surface waters. As described in Chapter 1, this type of information gap largely reflects
37 the difficulty of determining exact causation between stressors and effects.
38
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1 3.3 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF GROUND
2 WATER AND THEIR EFFECTS ON HUMAN HEALTH AND THE
3 ENVIRONMENT?
4 3.3.1 Introduction
5 A large portion of the world's fresh water resides underground, stored within cracks and pores in the rock
6 that makes up Earth's crust. The U.S. Geological Survey estimates that there are approximately 1,000,000
7 cubic miles of ground water within one half-mile of the Earth's surface—30 times the volume of all the
8 world's fresh surface waters.5 Many parts of the U.S. rely heavily on ground water for human uses (e.g.,
9 drinking, irrigation, industry, livestock), particularly areas with limited precipitation (e.g., the Southwest),
10 limited surface water resources, or high demand from agriculture and growing populations (e.g., Florida).
11 Half of the U.S. population (51 percent) relies on ground water for domestic uses.6
12 Ecological systems also rely on ground water. For example, some wetlands and surface waters are fed by
13 springs and seeps, which occur where a body of ground water—known as an aquifer—reaches the Earth's
14 surface. While the contribution of ground water to stream flow varies widely among streams, hydrologists
15 estimate that the average contribution of ground water is an estimated 40 to 50 percent in small and
16 medium sized streams. The ground water contribution to all stream flow in the U.S. may be as large as 40
17 percent.7
18 The extent of ground water refers to the amount available, typically measured in terms of volume or
19 saturated thickness of an aquifer. The condition of ground water reflects a combination of physical,
20 biological, and chemical attributes. Physical properties reflect patterns of flow—i.e., the volume, speed,
21 and direction of ground water flow in a given location. Biologically, ground water can contain a variety of
22 organisms, including bacteria, viruses, protozoans, and other pathogens. Ground water can also contain a
23 variety of chemicals, which may occur naturally or as a result of human activities. Chemicals that may
24 occur in ground water include nutrients, metals, radionuclides, salts, and organic compounds such as
25 petroleum products, pesticides, and solvents. These chemicals may be dissolved in water or—in the case
26 of insoluble organic contaminants—exist as undissolved plumes.
27 Many stressors can affect the extent of ground water, including patterns of precipitation and snowmelt
28 and human activities that change or redistribute the amount of ground water in an aquifer. One major way
29 humans influence ground water extent is by withdrawing water for drinking, irrigation, or other uses (e.g.,
30 ground water extracted to lower the water table for mining operations). Other human activities can
31 increase ground water levels, such as surface irrigation runoff recharging a shallow aquifer, or water
32 pumped directly into the ground in order to store surface waters for future use, or to aid in oil and gas
33 extraction. Human activities can affect ground water extent indirectly, too; for example, impervious paved
34 surfaces may prevent precipitation from recharging ground water. In some cases, changes in ground water
35 extent may be caused by a combination of these human and natural factors—e.g., droughts that require
5 U.S. Geological Survey. 1999. Ground water (general interest publication). Reston, VA.
6 Ibid
7 Alley, W.M, T.E. Reilly, and O.L. Franke. 1999. Sustainability of ground-water resources. Circular 1186. Denver,
CO: U.S. Geological Survey.
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1 humans to withdraw more water from the ground (e.g., for irrigation), while at the same time providing
2 less precipitation for recharge. Additionally, some aquifers are more susceptible than others to changes in
3 extent. For example, some deep aquifers may take thousands of years to recharge, particularly if they lie
4 below highly impermeable confining layers.
5 Aquifer depletion—i.e., decreased extent—can adversely affect the humans and ecosystems that directly
6 or indirectly depend on ground water. Less ground water available for human or ecological use could
7 result in lower lake levels or—in extreme cases—cause perennial streams to become intermittent or
8 totally dry, thus harming aquatic and riparian plants and animals that depend on regular surface flows.
9 Areas with a high water table may have plant communities that tap ground water directly with their roots,
10 so even a slight lowering of the aquifer could affect native species—which in turn could benefit invasive
11 species.8 In addition, lower water table levels may lead to land subsidence and sinkhole formation in areas
12 of heavy withdrawal, which can damage buildings, roads, and other structures and can permanently
13 reduce aquifer recharge capacity by compacting the aquifer medium (soil or rock). Finally, changes in the
14 ground water flow regime can lead to consequences such as salt water intrusion, in which saline ground
15 water migrates into aquifers previously occupied by fresh ground water.
16 Although aquifer depletion can have serious effects, the opposite, far less common problem—too much
17 ground water—can also be detrimental. Too much ground water discharge to streams can cause erosion
18 and can alter the balance of aquatic plant and animal species, as has been reported in association with
19 some mining sites.9
20 Like extent, condition is influenced by both natural sources and human activities. Some ground water has
21 high levels of naturally occurring dissolved solids (salinity), or metals such as arsenic that can be present
22 as a result of natural rock formations. Land use can affect the condition of ground water; for example,
23 pesticides, fertilizers, and other chemicals applied to the land can leach into ground water, while waste
24 from livestock and other animals can contribute contaminants such as nutrients, organic matter, and
25 pathogens. Shallow and unconfined aquifers are particularly susceptible to this type of contamination. In
26 addition, landfills may leach metals, solvents, and other contaminants into ground water (particularly
27 older landfills that do not have liners and leachate collection systems). Mining operations can mobilize
28 toxic metals, acidic compounds, and other substances that can impact the condition of ground water.
29 Finally, chemical or biological contaminants may enter aquifers as a result of unintentional releases,
30 including chemical spills on land, leaks from storage tanks, sewers or septic systems, and unplugged
31 abandoned wells that allow a direct route of entry for contaminants.
32 Stressors that affect ground water condition ultimately affect the condition of water available for drinking,
33 irrigation, or other human needs. In some cases, treatment may be needed to ensure that finished drinking
34 water does not pose risks to human health. Because drinking water can come from many different types of
35 water bodies, and because of the many complex issues associated with treatment and regulation of
36 drinking water, this topic is addressed in greater detail in its own section of this report, Section 3.6. The
37 condition of ground water also can affect ecological systems. For example, many fish species depend on
8 Grantham, C. 1996. An assessment of ecological impacts of ground water overdraft on wetlands and riparian areas
on the United States. EPA/813/S-96/001. Washington, DC: U.S. Environmental Protection Agency.
9 U.S. DOI (Department of the Interior). 2002. Hydrologic impacts of mining. Chapter 1. In: Permitting hydrology, a
technical reference document for determination of probable hydrologic consequence (PHC) and cumulative
hydrologic impact assessments (CHIA). Washington, DC. Accessed November 8, 2003.
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1 cold, clear spring-fed waters for habitat or spawning grounds.10'11 In some cases, aquifers themselves may
2 constitute ecosystems. For example, caves and sinkholes are home to many types of aquatic fauna,
3 including invertebrates and fish adapted to life underground.12 Ground water can also affect the condition
4 of other environmental media. For example, volatile ground water contaminants can potentially migrate
5 into indoor air via soil vapor intrusion.
6 In many ways, extent and condition are intertwined. For example, stressors that affect extent—such as
7 withdrawal or injection—can also alter physical parameters of the ground water flow regime, such as
8 velocity and direction of flow. These physical alterations can affect patterns of discharge to surface
9 waters, as well as the movement of water and contaminants within the ground (e.g., salt water intrusion).
10 3.3.2 ROE Indicators
11 This report presents an indicator of ground water condition based on a nationwide survey of shallow wells
12 in watersheds where agriculture is the predominant land use. The data come from the U.S. Geological
13 Survey's NAWQA study of major river basins with agricultural activities, representing a large portion of
14 the nation's land area. Agricultural land use is among the major sources of certain ground water
15 contaminants such as nutrients and pesticides.
16 Table 3.3.1. ROE Indicators of the Trends in Extent and Condition of Ground Water and their
17 Effects on Human Health and the Environment
18
NATIONAL INDICATORS
Nitrate and Pesticides in Shallow Ground Water in Agricultural
Watersheds
LOCATION
3.3.2 -p. 3-44
10 Prichard, D., J. Anderson, C. Correll, J. Fogg, K. Gebhardt, R. Krapf, S. Leonard, B. Mitchell, and J. Stasts. 1998.
Riparian area management: a user guide to assessing proper functioning condition and the supporting science for
lotic areas. Technical reference 1737-15. Denver, CO: U.S. Department of the Interior, Bureau of Land
Management, National Applied Resource Sciences Center. 126 pp.
11 Boyd, M., and D. Sturdevant. 1997. The scientific basis for Oregon's stream temperature standard: common
questions and straight answers. Portland, OR: Oregon Department of Environmental Quality.
12 Elliott, W.R. 1998. Conservation of the North American cave and karst biota. In: Wilkens, H., D.C. Culver, and
W.F. Humphreys, eds. Subterranean biota. Amsterdam, The Netherlands: Elsevier (Ecosystems of the World series).
pp. 665-689. Preprint online at
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INDICATOR:
Watersheds
Nitrate and Pesticides in Shallow Ground Water in Agricultural
3 Nitrogen is a critical plant nutrient, and most nitrogen is used and reused by plants within an ecosystem
4 (Vitousek et al., 2002), so in undisturbed ecosystems minimal "leakage" occurs into ground water, and
5 concentrations are very low. When nitrogen fertilizers are applied in amounts greater than can be
6 incorporated into crops or lost to the atmosphere, however, nitrate concentrations in ground water can
7 increase. Elevated nitrogen levels in ground water also might result from disposal of animal waste or
8 onsite septic systems. Nitrate contamination in shallow ground water (less than 100 feet below land
9 surface) raises potential concerns for human health where untreated shallow ground water is used for
10 domestic water supply. High nitrate concentrations in drinking water pose a risk for methemoglobinemia,
11 a condition that interferes with oxygen transport in the blood of infants (U.S. EPA, 2004).
12 More than one billion pounds of pesticides (measured as pounds of active ingredient) are used in the U.S.
13 each year to control weeds, insects, and other organisms that threaten or undermine human activities
14 (Aspelin, 2003). About 80 percent of the total is used for agricultural purposes. Although pesticide use
15 has resulted in increased crop production and other benefits, pesticide contamination of ground water
16 poses potential risks to human health if contaminated ground water is used as a drinking water source—
17 especially if untreated.
18 This indicator reports on the occurrence of nitrate and pesticides in shallow ground water in watersheds
19 where agriculture is the primary land use, according to criteria outlined in Gilliom et al. (2006). Ground
20 water samples were collected by the U.S. Geological Survey's National Water Quality Assessment
21 (NAWQA) program from 1992 to 2001. NAWQA surveyed 51 major river basins and aquifer regions
22 across the contiguous United States during this period; the agricultural watersheds sampled were within
23 34 of these study units. Although agriculture is more prevalent in some parts of the country than in others,
24 the watersheds were chosen to reflect a broad range of hydrogeologic conditions and agricultural
25 activities. Ground water samples were collected from existing household wells where possible and new
26 observation wells otherwise, all targeted at the uppermost aquifer and avoiding locations where ground
27 water condition could be biased by point sources (e.g., directly downgradient from a septic system). Most
28 of the wells sampled ground water from less than 20 feet below the water table, indicating as directly as
29 possible the influence of land use on shallow ground water quality. To the extent feasible, the wells were
30 intended to sample recently recharged water. Most wells were sampled once; a few were sampled
31 multiple times as part of a detailed nutrient study, and the results were averaged. Related indicators report
32 concentrations of nutrients and pesticides in streams that drain agricultural watersheds (see the N and P in
33 Agricultural Streams indicator, p. 3-25, and the Pesticides in Agricultural Streams indicator, p. 3-32).
34 The nitrate component of this indicator represents 1,423 wells. Results are compared with the federal
35 drinking water standard of 10 mg/L, which is EPA's Maximum Contaminant Level (MCL) to prevent
36 methemoglobinemia (U.S. EPA, 2006). MCLs are enforceable standards representing the highest level of
37 a contaminant that is allowed in finished drinking water. MCLs take into account cost and best available
38 treatment technology, but are set as close as possible to the level of the contaminant below which there is
39 no known or expected risk to health, allowing for a margin of safety.
40 Data on 75 pesticides and 8 pesticide degradation products were collected from 1,412 of the wells in the
41 NAWQA study. These chemicals account for approximately 78 percent of the total agricultural pesticide
42 application in the United States by weight during the study period (Gilliom et al., 2006). Three types of
43 U.S. EPA human health-related standards and guidelines were used to evaluate pesticide data: Maximum
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3-44
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1 Contaminant Levels (MCLs) (as described above),
2 Cancer Risk Concentrations (CRCs), and Lifetime
3 Health Advisories (HA-Ls). In all three cases, the
4 standard and guideline levels are concentrations
5 pertaining to lifetime exposure through drinking water
6 The CRC is a guideline for potential carcinogens
7 associated with a specified cancer risk of 1 in
8 1,000,000, based on drinking water exposure over a
9 70-year lifetime. The HA-L is an advisory guideline
10 for drinking water exposure over a 70-year lifetime,
11 considering non-carcinogenic adverse health effects.
12 Specific standards and guidelines used for this
13 indicator are listed in Gilliom et al. (2006), and
14 additional information on these types of benchmarks,
15 their derivation, and their underlying assumptions is
16 provided in Nowell and Resek (1994). For this
17 indicator, if a chemical had multiple benchmarks, the
18 MCL took precedence; if no MCL was available, the
19 lower of the CRC (at 1 in 1,000,000 cancer risk) and
20 HA-L values was selected. An exceedance was
21 identified if a yearly, time-weighted mean
22 concentration exceeded the relevant standard or
23 guideline (Gilliom et al., 2006).
24 What the Data Show
25 During the 1992-2001 period:
26 • Nitrate concentrations were above 2 mg/L
27 in 58 percent of wells sampled in areas
28 where agriculture is the primary land use
29 (Exhibit 3-14). By comparison,
30 background nitrate levels in relatively
31 undeveloped areas are generally expected
32 to be below 1 mg/L (Nolan and Hitt,
33 2002).
34 • Nitrate concentrations in about 21 percent
35 of the wells exceeded the federal drinking
3 6 water standard (10 mg/L).
37 • About 60 percent of wells had a least one
38 detectable pesticide compound, and 9.4
39 percent had detectable levels of five or
40 more pesticides (Exhibit 3-15). According
41 to NAWQA data, approximately 1 percent
42 of the wells in agricultural watersheds had
43 one or more pesticides at concentrations
44 exceeding human health standards or
45 guidelines (Gilliom et al., 2006).
Exhibit 3-14. Nitrate in shallow ground water
in agricultural watersheds of the contiguous
U.S., 1992-2001a
80
CO
93 60
'o
CI
£40
a.
20
n
42.2
23.0
13.5
21.4
Concentration:11
D Less than 2 mg/L
D 2 to 6 mg/L
D 6 to 10 mg/L
D 10 mg/L or more
Coverage: 1,423 shallow wells In
watersheds In which agriculture is
the predominant land use, according
to criteria outlined in Gilliom et al.,
2006. These watersheds are within
34 major river basins and aquifer
regions studied by the USGS
NAWQA program.
bEPA's drinking water standard for
nitrate is a Maximum Contaminant
Level (MCL) of 10 mg/L.
Data source: USGS, National Water
Quality Assessment (NAWQA)
Program
Exhibit 3-15. Pesticides in shallow ground
water in agricultural watersheds of the
contiguous U.S., 1992-2001a'b
100
80
60
40
20
39.4
31.4
19.8
9.4
Number of compounds
delected:
D 0
D 1or2
• 3 or 4
D 5 or more
"Coverage: 1,412 shallow wells in
watersheds in which agriculture Is
the predominant land use, according
to criteria outlined in Gilliom et al.,
2006. These watersheds are within
34 major river basins and aquifer
regions studied by the USGS
NAWQA program.
bSamples were analyzed for 75
pesticides and 8 pesticide
degradation products.
Data source: Gilliom et al., 2006
(Appendix 6)
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1 Indicator Limitations
2 • These data only represent conditions in agricultural watersheds within 34 of the major river
3 basins and aquifer regions sampled by the NAWQA program from 1992 to 2001. While they
4 were chosen to be representative of agricultural watersheds across the United States, they are
5 the result of a targeted sample design. The data also are highly aggregated and should only be
6 interpreted as an indication of national patterns.
7 • This indicator does not provide information about trends over time, as the NAWQA program
8 has completed only one full sampling cycle to date. Completion of the next round of
9 sampling will allow trend analysis, using the data presented here as a baseline.
10 • Drinking water standards or guidelines do not exist for 43 percent (36 of 83) of the pesticides
11 and pesticide degradation products analyzed. Current standards and guidelines also do not
12 account for mixtures of pesticide chemicals and seasonal pulses of high concentrations.
13 Possible pesticide effects on reproductive, nervous, and immune systems, as well as on
14 chemically sensitive individuals, are not yet well understood.
15 • This indicator does not provide information on the extent to which pesticide concentrations
16 exceed or fall below standards, nor the extent to which they exceed or fall below other
17 reference points (e.g., Maximum Contaminant Level Goals [MCLGs] for drinking water).
18 Data Sources
19 Summary data for this indicator were provided by the U.S. Geological Survey's National Water Quality
20 Assessment (NAWQA) program. Pesticide data have also been published in Gilliom et al. (2006), with
21 raw sampling data available online in Appendix 6 of the same report
22 (http://ca.water.usgs.gov/pnsp/pubs/circ 129 l/appendix6/). Summary data for nitrate have not yet been
23 published; however, data from individual sample sites can be obtained from NAWQA's online data
24 warehouse (USGS, 2006).
25 References
26 Aspelin, A.L. 2003. Pesticide usage in the United States: trends during the 20th century. Raleigh, NC:
27 Center for Integrated Pest Management, North Carolina State University.
28
33 Nolan, B.T., and K.J. Hitt. 2002. Nutrients in shallow ground waters beneath relatively undeveloped areas
34 in the conterminous United States: U.S. Geological Survey water resources investigation report 02-4289.
35 17 pp.
36 Nowell, L.H., and E.A. Resek. 1994. National standards and guidelines for pesticides in water, sediment,
37 and aquatic organisms: application to water-quality assessments: Rev. Environ. Contam. Toxicol. 140:1-
38 164.
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1 U.S. EPA. 2006. List of Drinking Water Contaminants and MCLs.
2
3 U.S. EPA. 2004. Consumer factsheet on nitrates/nitrites.
4
5 USGS. 2006. USGS National Water Quality Assessment data warehouse. Accessed 2006.
6
7 Vitousek, P., H. Mooney, L. Olander, and S. Allison. 2002. Nitrogen and nature. Ambio 31:97-101.
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1 3.3.3 Discussion
2 What This Indicator Says About Trends in the Extent and Condition of
3 Ground Water and Their Effects on Human Health and the Environment
4 The Nitrate and Pesticides in Ground Water indicator (p. 3-44) describes the extent to which the condition
5 of shallow ground water may be influenced by human stressors—in this case, certain chemicals applied to
6 land in agricultural areas. Collectively, the agricultural watersheds sampled across the nation had average
7 nitrate concentrations that were substantially higher than the background levels one might expect in an
8 undisturbed watershed. Nitrate concentrations exceeded MCLs for nitrate in one-fifth of the wells, though
9 this does not necessarily reflect the condition of the water people drink if it is tested and treated. Nitrate
10 concentrations were often high enough that they could impact ecological systems upon being introduced
11 into surface waters.13'14 Pesticide compounds were detected frequently (more than half of the shallow
12 wells sampled). However, detected pesticide concentrations rarely exceeded human health-based
13 reference points in the samples collected for this indicator.
14 Limitations, Gaps, and Challenges
15 One challenge in answering this question is that there are currently no national indicators of ground water
16 extent. Comprehensive national data do not exist, particularly in terms of real-time water level
17 monitoring. Statistics on water use and withdrawal might be considered a surrogate for ground water
18 extent, but because withdrawal is but one factor that affects extent (other factors include recharge rate and
19 flow patterns), the relationship between withdrawal and extent differs from one location to another. Thus,
20 the issue of extent currently represents an information gap.
21 There are also several limitations, gaps, and challenges in addressing the issue of ground water condition.
22 One notable limitation to the Nitrate and Pesticides in Ground Water indicator (p. 3-44) is that it does not
23 provide information about trends over time. The indicator is also limited in its ability to represent the
24 condition of entire aquifers. Because ground water condition is vertically heterogeneous, results from one
25 depth do not necessarily represent other depths. This indicator characterizes the uppermost layer of
26 shallow aquifers, which are used by many private wells. It does not provide information about the
27 condition of deeper aquifers, which are more likely to be used for public water supplies.
28 The Nitrate and Pesticides in Ground Water indicator provides a representative national picture of shallow
29 ground water condition in agricultural watersheds. At the present time, similar indicators do not exist for
30 ground water in watersheds with non-agricultural land uses. Non-agricultural watersheds—particularly
31 urban areas—reflect a different set of stressors, and to some extent a different set of chemicals (i.e.,
32 VOCs and hydrocarbons like MTBE15). Because many ground water stressors in urban areas are localized
13 Howarth, R., D. Anderson, J. Cloern, C. Elfring, C. Hopkinson, B. Lapointe, T. Malone, N. Marcus, K.
McGlathery, A. Sharpley, and D. Walker. 2000. Nutrient pollution of coastal rivers, bays, and seas. Issues in
ecology, number?. Washington, DC: Ecological Society of America.
14 Jackson, R.., S. Carpenter, C. Dahm, D. McKnight, R. Naiman, S. Postel, and S. Running. 2001. Water in a
changing world. Issues in ecology, number 9. Washington, DC: Ecological Society of America.
15 Delzer, G.C., and T. Ivahnenko, 2003. Occurrence and temporal variability of methyl tert-butyl ether (MTBE) and
other volatile organic compounds in select sources of drinking water: results of the focused survey. USGS series:
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1 events such as plumes resulting from chemical spills or underground storage tank (UST) leaks, they may
2 be harder to characterize on a national level—a potential challenge to gathering more information about
3 ground water condition. Salt water intrusion is another issue that tends to occur locally, and for which
4 national-scale data are not available.
water-resources investigations report. Report no. 2002-4084. Reston, VA: U.S. Geological Survey.
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1 3.4 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF WETLANDS AND
2 THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT?
3 3.4.1 Introduction
4 The United States has many types of wetlands, which include marshes, swamps, bogs, and similar marine,
5 estuarine, or freshwater areas that are periodically saturated or covered by water. Wetlands are an integral
6 part of the landscape because they provide habitat for a diverse array of plants and animals, act as buffers
7 to flooding and erosion, and serve as key links in the global water and biogeochemical cycles.
8 In terms of extent, wetlands currently cover 5.5 percent of the surface area of the contiguous 48 states,
9 with freshwater wetlands accounting for nearly 95 percent of the current wetland acreage and marine and
10 estuarine wetlands accounting for the remaining 5 percent.16 Condition is somewhat harder to measure, as
11 it reflects a combination of physical, chemical, and biological attributes. To be in healthy condition,
12 however, a wetland should generally demonstrate good water quality and support native plant and animal
13 communities, without the presence of invasive non-indigenous species. A healthy wetland should not
14 show signs of stress related to substantial degradation or cumulative effects of smaller degradations, and
15 should be free of modifications that restrict water flow into, through, or out of the wetland, or that alter
16 patterns of seasonality.
17 Wetlands can be classified by many different attributes. First, they can be divided by basic location—
18 freshwater, marine, or estuarine. Wetlands also may be classified based on dominant vegetation type. For
19 example, swamps are dominated by trees and shrubs, while marshes are characterized by non-woody,
20 emergent (vertically oriented) plants like grasses and sedges. Other characteristics used to classify
21 wetlands include soil type, water source, and the length of time a given wetland is saturated.
22 The structure and function of any given wetland will be governed by a combination of interrelated factors,
23 including topography, underlying geology (e.g., mineral composition), the abundance and movement of
24 water (hydrology), and weather and climate. These factors ultimately determine which plant and animal
25 species will thrive in a given wetland.
26 All wetlands share a few basic physical, chemical, and biological attributes. By definition, all wetlands
27 are saturated or covered by water at least periodically, and wetland vegetation is adapted to these
28 conditions. Thus, wetlands are like sponges, with a natural ability to store water. Wetlands also tend to
29 have highly developed root systems that anchor trees and other vegetation in place. This web of roots not
30 only holds the soil in place, but also filters pollutants out of the water as it flows through.
31 Because of their physical, chemical, and biological properties, wetlands serve many important
32 environmental functions. They play an important role in improving natural water quality by filtering
33 pollutants. This function is particularly important to human health because it may affect the condition of
34 waters used as a source of drinking water—a topic described in greater detail in Section 3.6. Wetlands
35 also act as a buffer to protect the shoreline from erosion and storm damage. Because of their sponge-like
36 capacity to absorb water, wetlands slow the water's momentum and erosive potential and reduce flood
16 Dahl, T.E. 2006. Status and trends of wetlands in the conterminous United States 1998 to 2004. Washington, DC:
U.S. Department of the Interior, Fish and Wildlife Service,
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1 heights. During dry periods, the "sponge" releases water, which is critical in maintaining the base flow of
2 many surface water systems.
3 Wetlands are also among the most biologically productive natural ecosystems in the world. Microbial
4 activity in wetlands enriches the water and soil with nutrients. As the interface between terrestrial and
5 aquatic ecological systems, wetlands provide food and habitat for many plant and animal species,
6 including rare and endangered species. Because of these functions, wetlands support a number of human
7 activities, including commercial fishing, shellfishing, and other industries, as well as recreation,
8 education, and aesthetic enjoyment.
9 In addition, wetlands play a role in global biogeochemical cycles, particularly those driven in part by the
10 microbial processes that occur in wetlands (e.g., the mineralization of sulfur and nitrogen from decaying
11 plants and the methylation of mercury). Plant growth in wetlands provides a "sink" for many chemicals
12 including atmospheric carbon. If a wetland is disturbed or degraded, these cycles can be altered and some
13 of the chemicals may be released.
14 The extent of wetlands can be affected by a variety of natural stressors, such as erosion, land subsidence,
15 changes in precipitation patterns (e.g., droughts), sea level change, hurricanes, and other types of storms.
16 However, the vast majority of wetland losses and gains over the last few centuries have occurred as a
17 result of human activity.17 For years, people have drained or filled wetlands for agriculture or urban and
18 suburban development, causing habitat loss or fragmentation as well as a decline in many of the other
19 important functions outlined above, such as improving water quality. Conversely, other human activities
20 may increase the extent of wetlands—for example, creating shallow ponds or re-establishing formerly
21 drained or modified wetlands on farmlands.
22 Wetland extent may influence condition, as wetland loss may result in added stress to remaining
23 wetlands. For example, if fewer wetlands are available to filter pollutants from surface waters, those
24 pollutants could become more concentrated in remaining downgradient wetlands. Wetland loss and
25 fragmentation also lead to decreases in habitat, landscape diversity, and the connectivity among aquatic
26 resources (i.e., fragmented wetlands essentially become isolated wildlife refuges). Thus, stressors that
27 affect extent may ultimately affect condition as well.
28 Wetland condition also reflects the influence of stressors that affect topography, hydrology, climate, water
29 condition, and biodiversity. For example, human modifications such as pipes and channels can alter the
30 topography, elevation, or hydrology of wetlands, while withdrawal of ground water or upstream surface
31 waters can directly reduce inflow. Natural forces and human activities (e.g., hurricanes, sea level change,
32 and certain agricultural and forestry practices) can also affect wetlands through increased erosion or
33 sedimentation. Pollutants in ground water and fresh surface waters that flow into wetlands may be toxic to
34 plants and animals, and may also accumulate in wetland sediments. In addition, invasive species can alter
35 the composition of wetland communities. Some of the most well known invasives in the U.S. are wetland
36 species, including plants such as phragmites and purple loosestrife and animals such as the nutria (a South
37 American rodent introduced to the Chesapeake and Gulf states).
17 Dahl, T.E. 2000. Status and trends of wetlands in the conterminous United States, 1986 to 1997. Washington, DC:
U.S. Department of the Interior, U.S. Fish and Wildlife Service.
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1 Another key stressor to wetlands is conversion from one wetland type to another. Although conversion
2 can occur naturally through plant succession (such as marshes turning into forested wetlands over time),
3 human activities can cause more drastic changes, such as clearing trees from a forested wetland,
4 excavating a marsh to create an open water pond, or introducing certain invasive species (e.g., the nutria,
5 which converts tidal marsh to open water by removing vegetation). Even if wetland extent is not altered,
6 conversion from one type to another has a major ecological impact by altering habitat types and
7 community structure.
8 3.4.2 ROE Indicators
9 An ROE indicator describes trends in wetland extent, as well as specific activities that have contributed to
10 recent wetland losses and gains (Table 3.4.1). Data were collected as part of the U.S. Fish and Wildlife
11 Service's Wetlands Status and Trends survey, a probabilistic national survey of wetland acreage
12 conducted approximately every 10 years for the past half-century. There is no ROE indicator for wetland
13 condition.
14 Table 3.4.1. ROE Indicators of the Trends in Extent and Condition of Wetlands and their Effects
15 on Human Health and the Environment
16
NATIONAL INDICATORS
Wetland Extent, Change, and Sources of Change
LOCATION
3.4.2 -p. 3-53
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INDICATOR: Wetland Extent, Change, and Sources of Change
2 Wetlands support a variety offish and wildlife species and contribute to the aesthetic and environmental
3 quality of the U.S. Millions of Americans use freshwater wetlands annually for hunting, fishing, bird
4 watching and other outdoor activities. Estuarine wetlands provide valuable nursery, feeding, breeding,
5 staging, and resting areas for an array offish, shellfish, mammals, and birds (Dahl, 2000). In addition,
6 wetlands serve as ground water recharge areas and filter contaminants from surface runoff (Mitsch and
7 Gosselink, 1986). Destruction or alteration of wetlands, therefore, can have wide-ranging biological and
8 hydrological impacts.
9 Various lines of evidence suggest when European settlers first arrived, wetland acreage in the area that
10 would become the contiguous 48 states was more than twice what it is today (Dahl, 1990). Since then,
11 extensive losses have occurred due to draining and filling. In addition to the sheer loss of wetland
12 acreage, major ecological impacts also have resulted from the conversion of one wetland type to another,
13 such as clearing trees from a forested wetland or excavating a shallow marsh to create an open water
14 pond. These types of conversions change habitat types and community structure in watersheds and impact
15 the animal communities that depend on them (Dahl, 2000).
16 This indicator presents data from the U.S. Fish and Wildlife Service's Wetlands Status and Trends
17 survey. Conducted approximately every 10 years, this survey provides an estimate of the extent of all
18 wetlands in the contiguous U.S., regardless of land ownership. The Status and Trends survey uses a
19 probabilistic design, based initially on stratification of the 48 contiguous states by state boundaries and 35
20 physiographic subdivisions. Within these subdivisions are located 4,375 randomly selected, four square
21 mile (2,560 acre) sample plots. These plots are examined with the use of aerial imagery. Although the
22 imagery ranges in scale and type, most are 1:40,000 scale, color infrared from the National Aerial
23 Photography Program. Field verification is conducted to address questions of image interpretation, land
24 use coding, and attribution of wetland gains or losses; plot delineations are also completed. In the 1980s
25 to 1990s analysis, 21 percent of the sample plots were field-verified; in the most recent analysis, 32
26 percent were field-verified (Dahl, 2000, 2006). The Fish and Wildlife Service used the Cowardin et al.
27 (1979) definition of wetlands, which is part of the draft national standard for wetland mapping,
28 monitoring, and data reporting as determined by the Federal Geographic Data Committee.
29 This indicator shows trends in the total extent of wetlands, as well as the extent of several types of
30 freshwater and intertidal wetlands. In this analysis, freshwater wetlands include forested, shrub, emergent,
31 and non-vegetated wetlands (e.g., shallow ponds). Intertidal wetlands include marine areas (e.g., tidal flats
32 and sandbars) and estuarine areas (vegetated or not) that are exposed and flooded by the tides. Data on
33 wetland extent are described from several Status and Trends analyses: 1950s-1970s, 1970s-1980s, 1980s-
34 1990s, and 1998-2004 (Prayer et al., 1983; Dahl and Johnson, 1991; Dahl, 2000, 2006). For the most
35 recent period, the indicator also describes sources of wetland loss or gain, which the survey divided into
36 five distinct categories along with an "other" category (Dahl, 2006).
37 What the Data Show
38 Total wetland acreage declined over the last 50 years, but the rate of loss appears to have slowed over
39 time. From the 1950s to 1970s, an average of 458,000 acres was lost per year (Exhibit 3-16). By the
40 1986-1997 period, the loss rate had declined to 58,600 acres per year; and in the most recent study period,
41 1998-2004, wetland area increased at a rate of 32,000 acres per year (Exhibit 3-16).
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Exhibit 3-16. Average annual change in wetland
acreage in the contiguous U.S., 1954-2004
« 100,000
•~: -100,000
-200,000
-300,000
-400,000
-500,000
1954-1974 1974-1983 1986-1997
Reporting period
1998-2004
Data source: Dahl, 2006
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Since the 1950s, intertidal wetland
acreage has decreased by about
700,000 acres, or 12 percent (Exhibit
3-18, panel A). This category
includes marine, estuarine vegetated,
and estuarine non-vegetated
wetlands. Both estuarine types lost
acreage overall, with estuarine
vegetated wetlands, the predominant
type, losing over 400,000 acres
(panel B). Long-term trends,
however, indicate that losses of
intertidal wetlands have slowed over
time, with estuarine non-vegetated
wetlands actually gaining acreage
from 1998 to 2004 (panel C).
Gains and losses have varied by wetland type.
Freshwater forested wetlands, which make up more
than half of all freshwater wetlands, lost acreage from
the 1950s to the 1990s but have shown gains since
1998 (Exhibit 3-17, panel A). Freshwater emergent
wetlands have continued to lose acreage, although the
rate of loss has slowed recently (panel C). Among
freshwater categories, forested wetlands have sustained
the greatest absolute losses since the 1950s, about 9
million acres, while emergent wetlands have shown the
largest percentage loss (about 21 percent). Conversely,
the extent of freshwater shrub wetlands increased until
1998 but declined thereafter, suggesting that some of
the gains and losses in specific categories may reflect
conversion rather than outright wetland loss or gain
(Dahl, 2006; Exhibit 3-17, panel B). Shallow
freshwater ponds, meanwhile, have increased steadily
throughout the last 50 years, with current acreage more
than twice what it was in the 1950s (panel D). These
wetlands account for a large percentage of the recent
gains illustrated in Exhibit 3-17 (Dahl, 2006).
Exhibit 3-17. Extent of selected freshwater wetlands in the
contiguous U.S., 1950s-2000sa
I
Between 1998 and 2004, urban
development, rural development,
conversion to deepwater, and
silviculture all contributed to losses
in wetland acreage (Exhibit 3-19).
However, the net change in wetland
acreage during this period was
positive, due largely to wetland
creation and restoration on
agricultural lands (70,770 acres) and
A. Freshwater forested wetlands
61.2
51.9 507 52.0
I' . 507 .
Illl
B. Freshwater shrub wetlands
11.0
15.5 17.2 18.4 17.6
1950s
1970s 1980s 1990s 2000s
1950s 1970s 1980s 1990s 2000s
C. Freshwater emergent wetlands
33.1
I-*" ' £U.H
• I
28.4 26.4 26.3 26.1
1950s
1970s 1980s 1990s 2000s
D. Freshwater ponds
2.3
4.4 4.9 5.5 6.2
1950s
1970s 1980s 1990s 2000s
Decade
aBased on mid-decade surveys. No analysis was conducted for the 1960s.
Data source: Dahl, 2006
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1 on lands classified as "other" (349,600 acres). This "other" category includes conservation lands, areas in
2 transition from one land use to another, and other lands that do not fall into the major land use categories
3 as defined in Dahl (2006).
Indicator Limitations
Exhibit 3-18. Extent of marine and estuarine
wetlands in the contiguous U.S., 1950s-2000sab
A. All intertidal wetlands (marine + estuarine)0
6.00
• ^3 ^o 533 5.30
1950s
1970s 1980s
Decade
1990s 2000s
B. Estuarine vegetated wetlands
5.00 4.85 ,fi, .,cn .,,
14.62 4.60 4.57
1950s 1970s 1980s 1990s 2000s
Decade
C. Estuarine non-vegetated wetlands
0.74
1950s
0.68 0.59 0.59 0.60
1970s 1980s 1990s 2000s
Decade
Based on mid-decade surveys. No analysis was conducted for
the 1960s.
bSurveys did not include Pacific coast estuarine wetlands.
"Panel A Is the sum of panel B, panel C, and marine wetland acreage.
Data source: Dahl, 2006
Different methods were used in some of
the early schemes to classify wetland
types. As methods and spatial resolution
have improved over time, acreage data
have been adjusted, resulting in changes
in the overall wetland base over time, thus
reducing the accuracy of the trend.
Ephemeral waters and effectively drained
palustrine wetlands observed in farm
production are not recognized as wetland
types by the Status and Trends survey and
are therefore not included in the indicator.
Forested wetlands are difficult to
photointerpret and are generally
underestimated by the survey.
The aerial imagery used for this survey
generally does not allow detection of
small, isolated patches of wetland less
than about an acre.
Exhibit 3-19. Sources of wetland gain and loss
in the contiguous U.S., 1998-2004
400,000
-100,000
+349,600
-70,100 -88,960 -51,440 -18,000
Land use category
"Other" includes lands that do not fit into any of the other five
categories, such as conservation land and land in transition
between different uses.
Data source: Dahl, 2006
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1 • Alaska and Hawaii are not included in the Status and Trends survey.
2 • This survey does not include Pacific coast estuarine wetlands such as those in San Francisco
3 Bay, Puget Sound, or Coos Bay, Oregon.
4 Data Sources
5 Data for this indicator were obtained from Dahl (2006). Historical trends are based on data originally
6 presented in earlier Fish and Wildlife Service reports (Dahl, 2000; Dahl and Johnson, 1991; Prayer et al,
7 1983).
8 References
9 Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater
10 habitats of the United States. FWS/OBS-79/31. Washington, DC: U.S. Department of the Interior, Fish
11 and Wildlife Service.
12 Dahl, T.E. 2006. Status and trends of wetlands in the conterminous United States 1998 to 2004.
13 Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service.
14
15 Dahl, T.E. 2000. Status and trends of wetlands in the conterminous United States 1986 to 1997.
16 Washington, DC: U.S. Department of the Interior, U.S. Fish and Wildlife Service.
17
18 Dahl, T.E. 1990. Wetlands losses in the United States 1780s to 1980s. Washington, DC: U.S. Department
19 of the Interior, Fish and Wildlife Service,
20 Dahl, T.E., and C.E. Johnson. 1991. Status and trends of wetlands in the conterminous United States,
21 mid-1970s to mid-1980s. Washington, DC: U.S. Department of the Interior, U.S. Fish and Wildlife
22 Service,
23 Prayer, W.E., T.J. Monahan, D.C. Bowden, and F.A. Graybill. 1983. Status and trends of wetlands and
24 deepwater habitats in the conterminous United States, 1950s to 1970s. Ft. Collins, CO: Colorado State
25 University,
26 Mitsch, W.J., and J.G. Gosselink. 1986. Wetlands. New York, NY: Van Nostrand Reinhold Company Inc.
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1 3.4.3 Discussion
2 What This Indicator Says About Trends in the Extent and Condition of
3 Wetlands and Their Effects on Human Health and the Environment
4 Wetland extent in the contiguous 48 states is substantially lower than it was prior to widespread European
5 settlement and it generally continued to decline over the last 50 years (Wetlands indicator, p. 3-53). The
6 rate of loss of wetlands overall and for most types of wetlands has slowed over time, however, and since
7 1998 the overall extent of wetlands has actually increased. Not all types of wetlands have experienced the
8 same rate of losses or overall percent losses. For example, freshwater shrub wetlands actually increased
9 over the last 50 years—providing evidence of wetland conversion, most likely from forested wetlands to
10 shrub. The nation has also seen a steady increase in acreage of freshwater ponds, which account for a
11 substantial portion of the recent gains in overall wetland acreage.
12 This indicator also confirms the role of many of the stressors described in Section 3.4.1. Over the last
13 decade, development, forestry, and conversion to deepwater (e.g., marsh to open water) have led to losses
14 in wetland extent, while agricultural areas have experienced overall gains in wetland acreage. The other
15 source of new wetland acreage is from the "other" land use category, which reflects the growing
16 importance of constructed and restored wetlands, including ponds associated with golf courses and
17 residential development.
18 While this indicator does not directly quantify the condition of the nation's wetlands, it suggests that the
19 condition of many wetlands may be impacted. As discussed in Section 3.4.1, extent is only a partial
20 surrogate for condition because wetland loss can increase the stress on those wetlands that remain, while
21 decreasing their connectivity. Thus, the overall decline in extent over the last 50 years suggests the
22 potential for substantial ecological impacts such as habitat loss and increased flood impacts. Changes in
23 the extent of different types of wetlands also suggest changes in condition. Shallow ponds, which
24 constitute a large fraction of the recent gains in wetland acreage, will not perform the same range and type
25 of environmental functions as the vegetated wetlands that disappeared between the 1950s and the 1990s.
26 Similarly, evidence of wetland conversion indicates that even if extent is no longer declining rapidly,
27 changes in wetland structure and function are still occurring. In the past, studies have shown that wetlands
28 that have been created to mitigate for wetland losses have not yet provided the same functions and values
29 of the wetlands that were lost.18'19
30 Limitations, Gaps, and Challenges
31 By relying on aerial imagery and statistical surveying techniques, the Wetlands indicator (p. 3-53)
32 provides a national estimate without an impractical number of samples. However, a limitation to this
33 survey is that it may omit or undercount certain types of wetlands, including forested wetlands—which
34 are difficult to photo-interpret—and ephemeral or well-drained agricultural wetlands, which are not
35 necessarily obvious to the surveyor but are particularly threatened by development. This indicator also
18 National Research Council. 2001. Compensating for wetland losses under the Clean Water Act. Washington, DC:
National Academy Press,
19 Mack, J.J., and M. Micacchion. 2006. An ecological assessment of Ohio mitigation banks: vegetation,
amphibians, hydrology, and soils. Ohio EPA Technical Report WET/2006-1. Columbus, OH: Ohio Environmental
Protection Agency.
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1 does not include wetland parcels less than about 1 acre, which become more critical as larger wetlands are
2 fragmented into smaller pieces.
3 Wetland condition poses a larger challenge for assessment. While the Wetlands indicator (p. 3-53)
4 provides information that can be used to infer potential wetland condition, it does not explicitly measure
5 condition—in part because condition is difficult to quantify. Condition is made up of many different
6 attributes, and each wetland has its own unique baseline condition, with a unique hydrologic setting and
7 combination of plant and animal species. Some studies have quantified regional changes in specific
8 stressors; however, national indicators would have to bring together many regional datasets and cover
9 many different aspects of condition in order to be truly comprehensive. The lack of such national-scale
10 information is currently a gap in addressing the question of wetland condition. Potential human health
11 effects associated with wetland extent and condition are also difficult to quantify, and there are no ROE
12 indicators on this topic.
13 Another information gap concerns the spatial patterns of wetland change, which are not documented in
14 the existing national data. Are most large wetlands being left intact? Are human activities threatening to
15 fragment larger wetlands into smaller pieces that are less connected and more isolated, and therefore less
16 able to perform the desired ecological functions? Data on patterns of wetland loss—e.g., fragmentation
17 and edge effects—would be a useful complement to the existing data on overall losses and gains.
18
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1 3.5 WHAT ARE THE TRENDS IN EXTENT AND CONDITION OF COASTAL
2 WATERS AND THEIR EFFECTS ON HUMAN HEALTH AND THE
3 ENVIRONMENT?
4 3.5.1 Introduction
5 Coastal waters are one of the nation's most important natural resources, valued for their ecological
6 richness as well as for the many human activities they support. As the interface between terrestrial
7 environments and the open ocean, coastal waters encompass many unique habitats, such as estuaries,
8 coastal wetlands, seagrass meadows, coral reefs, mangrove and kelp forests, and upwelling areas.20
9 Coastal waters support many fish species for at least part of their life cycle, offering some of the most
10 productive fisheries habitats in the world. These waters also provide breeding habitat for 85 percent of
11 U.S. waterfowl and other migratory birds (largely in coastal wetlands),21 and support many other
12 organisms with high public visibility (e.g., marine mammals, corals, and sea turtles) or unique ecological
13 significance (e.g., submerged aquatic vegetation). For humans, coastal waters provide opportunities for
14 tourism and recreation, and they contribute to the economy through transportation, fisheries, and mining
15 and utilities.22 Lands adjacent to the coast are highly desirable places for people to live, and represent the
16 most densely developed areas in the nation.23
17 Extent and condition are two key variables in assessing coastal waters and their ability to serve ecological
18 and human needs. The extent of coastal waters—i.e., the spatial area—is particularly important in terms
19 of the extent of specific types of coastal waters, such as coastal wetlands. The condition of coastal waters
20 reflects a group of interrelated physical, chemical, biological, and ecological attributes. For example,
21 nutrient levels should be sufficient to support the food web but not so high as to cause eutrophication,
22 while toxic chemical contaminants in water and sediment may pose a threat to aquatic organisms or
23 accumulate in the food web. Of particular concern to human health are contaminants in consumable fish
24 and shellfish—a topic discussed separately in Section 3.8. Other key aspects of condition include levels of
25 pathogens and organisms that produce biotoxins—which may pose a risk to human health through aquatic
26 recreation or contaminated fish and shellfish, and which may impact the environment by injuring native
27 populations. Also important is the degree to which native plant and animal populations are healthy and
28 their habitats intact.
29 Many factors can affect the extent of coastal waters. For example, the extent of coastal wetlands may be
30 influenced by natural events such as erosion or storms, or by human activities such as draining or filling
31 wetlands for development. Natural processes can change the shape of a coastline, with wave action
20 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
21 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
22 National Oceanic and Atmospheric Administration. 2005. Economic statistics for NOAA. May 2005—fourth
edition. U.S. Department of Commerce.
23 National Oceanic and Atmospheric Administration. 2004. Population trends along the coastal United States:
1980-2008. Coastal trends report series. Silver Spring, MD: U.S. Department of Commerce, National Ocean
Service.
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1 eroding some areas while building up sediment in others, and rivers depositing sediments at their mouth.
2 Human stressors can alter these patterns—for example, through the construction of seawalls or barriers or
3 through the channeling of rivers, which can lead to subsidence in coastal areas that would otherwise be
4 naturally replenished by sediments.
5 Changes in extent may in turn affect the condition of coastal waters. For example, beach erosion and
6 coastal wetland loss can also affect contaminant and sediment levels, nutrient cycling, and the condition
7 of spawning and feeding grounds for fish, shellfish, and other coastal species. As described in Section
8 3.4.1, the loss of some wetlands can also affect the condition of the wetlands that remain.
9 Other stressors to the condition of coastal waters include nutrients, pathogens, and chemical
10 contaminants, which may pose risks to ecological systems or to human health. Nutrients and pathogens
11 occur naturally, but their abundance can be increased by human activities along the coast or in upstream
12 watersheds that ultimately discharge to coastal waters. Major sources include urban and suburban storm
13 water, agricultural runoff, and sewage discharge or overflows. Chemical contaminants may come from
14 these same sources, as well as from industrial activities that discharge treated wastewaters and from
15 atmospheric deposition of airborne pollutants.
16 Several other stressors can affect the quality of habitat and the status of native plant and animal
17 populations. For example, many species are sensitive to temperature and salinity, which can be influenced
18 by changes in weather patterns or the condition of freshwater inputs. Salinity is particularly important in
19 estuaries, where species may depend on a steady, reliable flow of fresh water. Another factor affecting the
20 status of native communities is the presence and abundance of non-indigenous species—particularly
21 invasive species that can kill or crowd out native populations, or otherwise alter coastal watersheds.
22 Populations offish, shellfish, marine mammals, and other species used by humans also may be affected
23 by overharvesting.
24 In many cases, stressors that affect coastal condition are interrelated. For example, excess nutrients can
25 cause algal blooms (and subsequent decay) that result in low dissolved oxygen (DO) and reduced water
26 clarity—the chain of events known as eutrophication. Temperature and salinity can also influence algal
27 blooms. Some algae, such as "red tide," produce toxins that pose risks to humans.
28 3.5.2 ROE Indicators
29 Five National Indicators and three Regional Indicators characterize the extent and condition of coastal
30 waters. National Indicators describe sediment quality, benthic community condition, contamination in fish
31 tissue, and several aspects of coastal water quality, as well as trends in the extent of marine and estuarine
32 wetlands. The Regional Indicators characterize trends in harmful algal blooms, the extent of areas with
33 low dissolved oxygen (i.e., hypoxia) and the extent of submerged aquatic vegetation (SAV). These
34 Regional Indicators reflect conditions in three important and unique coastal water bodies: the Gulf of
35 Mexico, Long Island Sound, and the Chesapeake Bay.
36 The National Indicator on wetland extent is based on data gathered from aerial and ground surveys
37 conducted as part of the U.S. Fish and Wildlife Service's Wetlands Status and Trends study, a long-term
38 statistical sampling effort. The other four National Indicators are derived from EPA's second National
39 Coastal Condition Report (NCCRII), which involved probabilistic surveys designed to represent 100
40 percent of estuarine acreage in the contiguous 48 states and Puerto Rico. In addition to national totals,
41 these four indicators also present data by EPA Region. The Regional Indicator on trends in hypoxia
42 reflects data from two long-term water sampling programs, while the indicator on SAV is based on aerial
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1 imagery. The Harmful Algal Blooms indicator reflects water sampling guided by satellite imagery that
2 can detect blooms.
3
4
Table 3.5.1. ROE Indicators of the Trends in Extent and Condition of Coastal Waters and their
Effects on Human Health and the Environment
NATIONAL INDICATORS
Wetland Extent, Change, and Sources of Change
Trophic State of Coastal Waters (N/R)
Coastal Sediment Quality (N/R)
Coastal Benthic Communities (N/R)
Coastal Fish Tissue Contaminants (N/R)
REGIONAL INDICATORS
Submerged Aquatic Vegetation in the Chesapeake Bay
Hypoxia in the Gulf of Mexico and Long Island Sound
Harmful Algal Bloom Outbreaks Along the Western Florida Coastline
LOCATION
3.4.2 -p. 3-53
3.5.2 -p. 3-62
3.5.2 -p. 3-67
3.5.2-p. 3-71
3.8.2-p. 3-103
LOCATION
3.5.2-p. 3-74
3.5.2-p. 3-77
3.5.2-p. 3-81
5
6
N/R = National Indicator displayed at EPA Regional scale
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INDICATOR: Trophic State of Coastal Waters
2 While many water pollutants can lead to decreases in coastal water quality, four interlinked components
3 related to trophic state are especially critical: nutrients (nitrogen and phosphorus), chlorophyll-a,
4 dissolved oxygen (DO), and water clarity. Trophic state generally refers to aspects of aquatic systems
5 associated with the growth of algae, decreasing water transparency, and low oxygen levels in the lower
6 water column that can harm fish and other aquatic life. Nitrogen is usually the most important limiting
7 nutrient in estuaries, driving large increases of microscopic phytoplankton called "algal blooms," but
8 phosphorus can become limiting in coastal systems if nitrogen is abundant in a bioavailable form (U.S.
9 EPA, 2003). Nitrogen and phosphorus can come from point sources, such as wastewater treatment plants
10 and industrial effluents, and nonpoint sources, such as runoff from farms, over-fertilized lawns, leaking
11 septic systems, and atmospheric deposition. Chlorophyll-a is a surrogate measure of algal abundance.
12 Chlorophyll-a levels are increased by nutrients and decreased by filtering organisms (e.g., clams, mussels,
13 or oysters). High concentrations of chlorophyll-a indicate overproduction of algae, which can lead to algal
14 scums, fish kills, and noxious odors (U.S. EPA, 2004). Low dissolved oxygen levels and decreased clarity
15 caused by algal blooms or the decay of organic matter from the watershed are stressful to estuarine
16 organisms. Reduced water clarity (usually measured as the amount and type of light penetrating water to a
17 depth of one meter) also can be caused by storm-related events that cause erosion or mixing from the
18 sediments, and can impair the normal growth of algae and other submerged aquatic vegetation.
19 This indicator, developed as part of EPA's Coastal Condition Report, is based on an index constructed
20 from probabilistic survey data on five components: dissolved inorganic nitrogen, dissolved inorganic
21 phosphorus, chlorophyll-a, dissolved oxygen in bottom or near-bottom waters (where benthic life is most
22 likely to be affected), and water clarity (U.S. EPA, 2004). The survey, part of EPA's National Coastal
23 Assessment (NCA), was designed to provide a national picture of water quality by sampling sites in
24 estuarine waters throughout the contiguous 48 states and Puerto Rico. Each site was sampled once during
25 the period 1997-2000, within an index period from July to September. The indicator reflects average
26 condition during this index period.
27 Reference conditions were established for each EPA Region for nutrients, water clarity, and chlorophyll-a
28 because key factors like sediment load, mixing parameters, and ecosystem sensitivity naturally vary from
29 one Region to the next. A single national reference range of 2-5 mg/L was used for dissolved oxygen,
30 because concentrations below 2 mg/L are almost always harmful to many forms of aquatic life, and
31 concentrations above 5 mg/L seldom are (Diaz and Rosenberg, 1995; U.S. EPA, 2000). The process of
32 classifying individual sites varies by Region and is described in detail, along with the regional reference
33 conditions, in U.S. EPA, 2004 (pp. 19-20).
34 The overall water quality index is a compilation of the five components. For each site, the index is rated
35 high if none of the five components of the index received a score that would be considered
36 environmentally unfavorable (high nitrogen, phosphorus, or chlorophyll-a levels or low DO or water
37 clarity), and no more than one component was rated moderate. Overall water quality is low if more than
38 two components received the most unfavorable rating. All other sites receive a moderate index score. If
39 two or more components are missing, and the available components do not suggest a moderate or low
40 index rating, the site is classified as "unsampled." Data from the individual sites were expanded from the
41 probability sample to provide unbiased estimates of the water quality index and each of its components
42 for each EPA Region and for the entire nation.
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1 What the Data Show
2 According to the index, 40 percent of estuarine surface area nationwide exhibited high water quality over
3 the period 1997-2000, 11 percent had low water quality, and the remaining 49 percent was rated moderate
4 (Exhibit 3-20). Scores vary considerably among EPA Regions, ranging from high water quality in 71
5 percent of estuarine area in Region 1 to less than 10 percent in Regions 2 and 3. Only one EPA Region
6 had low water quality in more than 15 percent of its estuarine area (EPA Region 3, with 36 percent).
7 These percentages do not include the Great Lakes or the hypoxic zone in offshore Gulf Coast waters (see
8 the Hypoxia in Gulf of Mexico and Long Island Sound indicator, p. 3-77).
9 Nitrogen concentrations were low in 82 percent of estuarine area and high in 5 percent nationwide, and
10 were low in a majority of the estuarine area in all but one EPA Region (Exhibit 3-21). Regions 2 and 3
11 had the largest percentage of area with high concentrations (15 percent and 16 percent, respectively);
12 several other EPA Regions had no areas with high concentrations.
Exhibit 3-20. Coastal water quality index for the
contiguous U.S. and Puerto Rico, by EPA
Region, 1997-2000"
Percent of estuarine area in each category:
Coverage: Estjarine waters of the
contiguous 48 states and Puerto
Rico. Does not include the hypoxic
zone in offshore Gulf Coast waters.
b
U.S. figures reflect the total
sampled area. Unsampled areas
were not Included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by
EPA Region)
Exhibit 3-21. Nitrogen concentrations in coastal
waters of the contiguous U.S. and Puerto Rico,
by EPA Region, 1997-2000°
Nitrogen concentration:
Low
Moderate
High
Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
Regions
Region 4
Region 6
Region 9
Region 10
All U.S.°
74 17 9
27 23 15 34
63 14 16 7
88 12
84 13
88 12
100
82 13
EPA Regions
"Coverage: Estuarine waters of the
contiguous 48 states and Puerto Rico,
bThis indicator measures dissolved
inorganic nitrogen (DIN), which is the
sum of nitrate, nitrite, and ammonia.
CU.S. figures reflect the total
sampled area. Unsampled areas
were not included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by
EPA Region)
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1 Phosphorus concentrations were low in 53 percent of estuarine area and high in 9 percent nationwide
2 (Exhibit 3-22). Region 9 had the largest proportion of area exceeding reference conditions (52 percent),
3 while Region 10 had the least (none).
4 Chlorophyll-a concentrations were low in 51 percent and high in 8 percent of estuarine area nationwide
5 (Exhibit 3-23). Region 3 had the largest percentage of area exceeding reference conditions (27 percent);
6 all other EPA Regions had 10 percent or less in this category.
Exhibit 3-22. Phosphorus concentrations in
coastal waters of the contiguous U.S. and
Puerto Rico, by EPA Region, 1997-2000"'b
Phosphorus concentration:
Low
Moderate
High Unsampled
Percent of estuarine area in each category:
Region 1
58
32
10
Region 2
Region 3
Region 4
Region 6
Region 9
Region 10
All U.S.C
16 41 9 34
58 29 6 6
66 24 10
49 37 15
2 46 52
5 95
53 38 9
EPA Regions
0
Coverage: Estuarine waters of the
contiguous 48 states and Puerto Rico.
bThis indicator measures dissolved
inorganic phosphorus (DIP), which
equals orthophosphate.
CU.S. figures reflect the total
sampled area. Unsampled areas
were not included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by
EPA Region)
Exhibit 3-23. Chlorophyll-a concentrations in
coastal waters of the contiguous U.S. and Puerto
Rico, by EPA Region, 1997-2000°
Chlorophyll-a concentration:
Low
Moderate High Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
88
6
6
24
31
7
37
Region 3
Region 4
Region 6
Region 9
Region 10
13
54
27
All U.S.
33
57
10
53
41
6
87
80
51
13
20
41
8
Coverage: Estuarine waters of the
contiguous 48 states and
Puerto Rico.
bU.S. figures reflect the total sampled
area. Unsampled areas were not
included in the calculation.
Data source: U.S. EPA, 2004 (data
modified to report by EPA Region)
EPA Regions
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1 Bottom-water dissolved oxygen was above 5 mg/L in over three-fourths of the nation's estuarine area and
2 below 2 mg/L in only 4 percent (Exhibit 3-24). While effects vary with temperature and salinity, as a
3 general rule, concentrations of DO above 5 mg/L are considered supportive of marine life, concentrations
4 below 5 mg/L are potentially harmful, and concentrations below 2 mg/L—a common threshold for
5 hypoxia—are associated with a wider range of harmful effects (e.g., some juvenile fish and crustaceans
6 that cannot leave the area may die). Region 3 had the greatest proportion of estuarine area with low DO
7 (21 percent), while four EPA Regions had no area below 2 mg/L.
8 Water clarity exceeded reference conditions (i.e., higher clarity) in 62 percent of the nation's estuarine
9 area, while low water clarity was observed in 25 percent of estuarine area (Exhibit 3-25). Region 3 had
10 the largest proportion of area with low clarity (43 percent), while Region 1 had the least (none).
11
Exhibit 3-24. Dissolved oxygen levels in
coastal waters of the contiguous U.S. and
Puerto Rico, by EPA Region, 1997-2000"
Dissolved oxygen concentration:
High
(>5mg/L)
Moderate
(2-5 mg/L)
Low
(<2mg/L)
Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
Regions
Region 4
Region 6
Region 9
Region 10
All U.S.b
87 11
66 21 13
53 21 21 4
75 23
84 16
98
67 31
76 20 4
EPA Regions
'Coverage: Bottom- or near bottom-
water dissolved oxygen in estuarine
waters of the contiguous 48 states
and Puerto Rico. Does not include
the hypoxic zone in offshore Gulf
Coast waters.
bU.S. figures reflect the total
sampled area. Unsampled areas
were not included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by
EPA Region)
Exhibit 3-25. Water clarity in coastal waters of
the contiguous U.S. and Puerto Rico, by EPA
Region, 1997-20003
Water clarity:
High
Moderate
Low
Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
Regions
Region 4
RegionB
Region 9
Region 10
All U.S."
95 4
82 710
38 14 43 5
66 12 19
47 22 31
65 11 24
44 18 38
62 13 25
'Coverage: Estuarine waters of the
contiguous 48 states and Puerto Rico.
bU.S. figures reflect the total sampled
area. Unsampled areas were not
included In the calculation.
Data source: U.S. EPA, 2004 (data
modified to report by EPA Region)
EPA Regions
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1 Indicator Limitations
2 • The indicator does not include data from the Great Lakes, which are monitored using a
3 different index design. The coastal areas of Hawaii and a portion of Alaska have been
4 sampled, but the data had not yet been assessed at the time this indicator was compiled. Data
5 are also not available for the U.S. Virgin Islands and the Pacific territories.
6 • Trend data are not yet available for this indicator. Because of differences in methodology, the
7 data presented here are not comparable with data that appeared in EPA's first National
8 Coastal Condition Report (NCCR I). The data presented here will serve as a baseline for
9 future surveys.
10 • The National Coastal Assessment surveys measure dissolved oxygen conditions only in
11 estuarine waters and do not include observations of dissolved oxygen concentrations in
12 offshore coastal shelf waters, such as the hypoxic zone in Gulf of Mexico shelf waters.
13 • At each sample location, the components of this indicator may have a high level of temporal
14 variability. This survey is intended to characterize the typical distribution of water quality
15 conditions in coastal waters during an index period from July through September. It does not
16 consistently identify the "worst-case" condition for sites experiencing occasional or
17 infrequent hypoxia, nutrient enrichment, or decreased water clarity at other times of the year.
18 Data Sources
19 This indicator is based on an analysis published in EPA's National Coastal Condition Report II (U.S.
20 EPA, 2004). Summary data by EPA Region have not been published, but were provided by EPA's
21 National Coastal Assessment program. Underlying sampling data are housed in EPA's National Coastal
22 Assessment database (U.S. EPA, 2005) (http://www.epa.gov/emap/nca/html/data/index.html).
23 References
24 Diaz, R.J., and R. Rosenberg. 1995. Marine benthic hypoxia: a review of its ecological effects and the
25 behavioral responses of benthic macrofauna. Oceanogr. Mar. Biol. Ann. Rev. 33:245-303.
26 U.S. EPA. 2005. EMAP national coastal database. Accessed 2005.
27
28 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
29
30 U.S. EPA. 2003. Mid-Atlantic integrated assessment, MAIA—estuaries 1997-98, summary report.
31 EPA/620/R-02/003. Narragansett, RI.
32 U.S. EPA. 2000. Ambient aquatic life water quality criteria for dissolved oxygen (saltwater): Cape Cod to
33 Cape Hatteras. EPA/822/R-00/12.
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NDICATOR: Coastal Sediment Qualit
2 Contaminated sediments can pose an immediate threat to benthic organisms and an eventual threat to
3 entire estuarine ecosystems. Sediments can be resuspended by anthropogenic activities, storms or other
4 natural events; as a result, organisms in the water column can be exposed to contaminants, which may
5 accumulate through the food web and eventually pose health risks to humans (U.S. EPA, 2004a).
6 There are several ways to measure sediment quality. Sediments can be assessed in terms of their toxicity
7 to specific organisms in bioassays, or in terms of the levels of contaminants that are present. Sediment
8 quality also can be inferred by assessing the condition of benthic communities, which largely reflect the
9 quality of the sediments in which they live (although other stressors may be reflected as well). To
10 generate a more complete picture of sediment quality, scientists frequently use several of these measures
11 together.
12 This indicator presents data on sediment toxicity and contaminant levels. The data are from probabilistic
13 surveys conducted as part of EPA's National Coastal Assessment (NCA) and presented in EPA's second
14 National Coastal Condition Report (U.S. EPA, 2004b). The survey was designed to provide a national
15 picture of sediment quality by sampling sites in estuarine waters throughout the contiguous 48 states and
16 Puerto Rico. Each site was sampled once during the period 1997-2000, within an index period from July
17 to September. The indicator reflects average condition during this index period.
18 Sediment toxicity is typically determined using bioassays that expose test organisms to sediments and
19 evaluate their effects on the organisms' survival. For this indicator, toxicity was determined using a 10-
20 day static test on the benthic amphipod Ampelisca abdita, which is commonly used as a screening tool to
21 identify sediments that pose sufficient concern to warrant further study. Sediments were classified as
22 "potentially toxic" if the bioassays resulted in greater than 20 percent mortality (a reference condition), or
23 "not likely toxic" if the bioassays resulted in 20 percent mortality or less (U.S. EPA, 2004c).
24 Contaminant concentrations do not directly reflect toxicity because toxicity also depends on
25 contaminants' bioavailability, which is controlled by pH, particle size and type, organic content, and other
26 factors (e.g., mercury vs. methylmercury). Contaminant concentrations are a useful screening tool for
27 toxicity, however, when compared with concentrations known to cause particular effects on benthic life.
28 For this indicator, sediment samples were homogenized and analyzed for nearly 100 contaminants,
29 including 25 PAHs, 22 PCBs, 25 pesticides, and 15 metals, using standard wet chemistry and mass
30 spectroscopy. The observed concentrations were then compared with "effects range median" (ERM)
31 values established through an extensive review of toxicity tests involving benthic organisms, mostly
32 Ampelisca (Long et al., 1995). For each contaminant, the ERM represents the concentration at which
33 there is a 50 percent likelihood of adverse effects to an organism, based on experimental data. For this
34 indicator, a site was rated "potentially toxic" if one or more contaminants exceeded an ERM value. In
35 practice, about 25 percent of samples that exceed one ERM also cause more than 20 percent mortality in
36 the Ampelisca bioassay (Long, 2000).
37 Benthic community condition also can be a useful indication of sediment quality, particularly in terms of
38 chronic or community effects that would not be captured in an acute exposure bioassay. The NCA
39 evaluated estuarine sites for several aspects of benthic community condition, and these results are
40 presented as a separate ROE indicator (Coastal Benthic Communities, p. 3-71).
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1 What the Data Show
2
3
4
5
6
7
8
9
10
11
12
Nationwide, 6 percent of coastal sediments were rated "potentially toxic" based on the Ampelisca toxicity
screening assay, although there was considerable variability from one EPA Region to the next (Exhibit 3-
26). In Region 9, nearly 100 percent of estuarine area exhibited low sediment toxicity, while in some
other EPA Regions, as much as 20 percent of estuarine sediments were "potentially toxic." Data for
Region 6 are inconclusive because more than half of the Region's estuarine area was not sampled.
Nationally, contaminants were present at "potentially toxic" levels in 7 percent of estuarine sediments for
which contamination data were available (Exhibit 3-27). There was considerable variability in sediment
contamination from one EPA Region to the next, with Region 4 showing the largest proportion of
estuarine area with sediments not likely to be toxic (99.9 percent), and Region 2 showing the largest
proportion with "potentially toxic" sediments (24.4 percent).
Exhibit 3-26. Sediment toxicity in coastal
waters of the contiguous U.S. and Puerto Rico,
by EPA Region, 1997-2000"
Sediment toxicity:
Not likely toxicb
Potentially toxic0
Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
Region 3
Region 4
Regions
Region 9
Region 10
All U.S."
89.0
5.6
73.0
13.0
13.9
92.3
4.7
87.2
0.2 12.6
38.7
I11.0
60.3
5.4
3.0
99.8
I 0.2
79.9
20.1
94.0
6.0
EPA Regions
"Coverage: Estuarine waters of the
contiguous 48 states and Puerto Rico.
"Not likely toxic:
Mortality of test species = 20% or
lower
Potentially toxic:
Mortality of test species > 20%
dU.S. figures reflect the total sampled
area. Unsampled areas were not included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by EPA Region)
Exhibit 3-27. Sediment contamination in
coastal waters of the contiguous U.S. and
Puerto Rico, by EPA Region, 1997-2000"
Sediment contamination:
Not likely toxic"
Potentially toxic0
Unsampled
Percent of estuarine area in each category:
Region 1
Region 2
Regions
Region 4
Region 6
Region 9
Region 10
90.0
4.6
62.0
24.4 13.6
88.2
9.4
99.9
81.7
18.3
5.4
2.4
0.1
All U.S.'
92.8
98.1
93.0
1.9
7.0
EPA Regions
"Coverage: Estuarine waters of the
contiguous 48 states and Puerto Rico.
"Not likely toxic:
No contaminants above "effects range
median" (ERM)
'Potentially toxic:
One or more contaminants above
"effects range median" (ERM)
dU.S. figures reflect the total sampled area. Unsampled areas were
not included in the calculation.
Data source: U.S. EPA, 2004 (data modified to report by EPA Region)
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1 Although the two figures suggest that a similar percentage of the nation's estuarine sediments are
2 "potentially toxic," the original data source reports very little correlation between sites that caused >20
3 percent mortality in the Ampelisca bioassay and sites where one or more contaminants exceeded the ERM
4 (U.S. EPA, 2004b). It is not unusual to find a lack of correlation—particularly in cases where sediment
5 contaminants are neither highly concentrated nor completely absent—in part because some toxic
6 chemicals may not be bioavailable, some may not be lethal, and not all potentially toxic chemicals are
7 analyzed (see O'Connor et al, 1998, and O'Connor and Paul, 2000). These results underscore the utility
8 of a combined approach to screen for potentially toxic sediments.
9 Indicator Limitations
10 • The coastal areas of Hawaii and a portion of Alaska have been sampled, but the data had not
11 yet been assessed at the time this indicator was compiled. Data are also not available for the
12 U.S. Virgin Islands and the Pacific territories.
13 • Trend data are not yet available for this indicator. Because of differences in methodology, the
14 data presented here are not comparable with data that appeared in EPA's first National
15 Coastal Condition Report (NCCR I). The data presented here will serve as a baseline for
16 future surveys.
17 • Sample collection is limited to an index period from July to September. It is not likely that
18 contaminant levels vary from season to season, however.
19 • The Ampelisca bioassay is a single-organism screening tool, and the ERMs are general
20 screening guidelines based largely on toxicity data from Ampelisca. Thus, these measures do
21 not necessarily reflect the extent to which sediments may be toxic to the full range of biota
22 (including microbes and plants) that inhabit a particular sampling location.
23 • The Ampelisca bioassay tests only for short-term, not long-term, exposure. Both screening
24 tests characterize sediments in terms of their effects on benthic organism mortality. This
25 indicator does not capture other effects of sediment contaminants on benthic organisms, such
26 as disease, stress, and reproductive effects.
27 • This indicator cannot be compared quantitatively with indicators that use other types of
28 contaminant guidelines. For example, the Pesticides in Agricultural Streams indicator (p. 3-
29 32) uses thresholds intended to be protective of aquatic life with a margin of safety, instead of
30 thresholds shown to cause biological effects (e.g., ERMs). The ERM approach also is not
31 directly comparable with other sediment contaminant approaches, such as EPA's equilibrium
32 partitioning (EqP) benchmarks.
33 Data Sources
34 This indicator is based on an analysis published in EPA's National Coastal Condition Report II (U.S.
35 EPA, 2004). Summary data by EPA Region have not been published, but were provided by EPA's
36 National Coastal Assessment program. Underlying sampling data are housed in EPA's National Coastal
37 Assessment database (U.S. EPA, 2005) (http://www.epa.gov/emap/nca/html/data/index.html).
38 References
39 Long, E.R. 2000. Degraded sediment quality in U.S. estuaries: a review of magnitude and ecological
40 applications. Ecol. Appl. 10(2):338-349.
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1 Long, E.R., D.D. MacDonald, L. Smith, and F.D. Calder. 1995. Incidence of adverse biological effects
2 within ranges of chemical concentrations in marine and estuarine sediments. Environ. Manage. 19:81-97.
3 O'Connor, T.P., K.D. Daskalakis, J.L. Hyland, J.F. Paul, and J.K. Summers. 1998. Comparisons of
4 sediment toxicity with predictions based on chemical guidelines. Environ. Toxicol. Chem. 17(3):468-471.
5 O'Connor, T.P., and J.F. Paul. 2000. Misfit between sediment toxicity and chemistry. Mar. Pollut. Bull.
6 40(l):59-64.
7 U.S. EPA. 2005. EMAP national coastal database. Accessed 2005.
8
9 U.S. EPA. 2004a. Contaminated sediment in water.
10 U.S. EPA. 2004b. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
11
12 U.S. EPA. 2004c. The incidence and severity of sediment contamination in surface waters of the United
13 States—national sediment quality survey. Second edition. Washington, DC.
14
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NDICATOR: Coastal Benthic Communiti
2 Benthic communities are largely composed of macroinvertebrates, such as annelids, mollusks, and
3 crustaceans. These organisms inhabit the bottom substrates of estuaries and play a vital role in
4 maintaining sediment and water quality. They also are an important food source for bottom-feeding fish,
5 invertebrates, and birds. Communities of benthic organisms are important indicators of environmental
6 stress because they are particularly sensitive to pollutant exposure (Holland et al., 1987). This sensitivity
7 arises from the close relationship between benthic organisms and sediments—which can accumulate
8 environmental contaminants over time—and the fact that these organisms are relatively immobile, which
9 means they receive prolonged exposure to any contaminants in their immediate habitat (Sanders et al.,
10 1980; Nixon etal., 1986).
11 This indicator is based on a multi-metric benthic communities index that reflects overall species diversity
12 in estuarine areas throughout the contiguous United States (adjusted for salinity, if necessary) and, for
13 some regions, the presence of pollution-tolerant and pollution-sensitive species (e.g., Weisberg et al.,
1997; Engle and Summers, 1999; U.S. EPA, 2004).
The benthic community condition at each sample site
is given a high score if the index exceeds a particular
threshold (e.g., has high diversity or populations of
many pollution-sensitive species), a low score if it falls
below the threshold conditions, and a moderate score if
it falls within the threshold range. The exact structure
of the index and the threshold values vary from one
region to another, but comparisons between predicted
and observed scores based on expert judgment are used
to ensure that the classifications of sites from one
region to another are consistent (see U.S. EPA, 2004,
p. 15). Data were collected using probability samples,
so the results from the sampling sites provide unbiased
estimates of the distribution of index scores in
estuaries throughout each region.
Exh b 13 28 Coastal benthic communities
index for the contiguous U S and Puerto Rico,
by EPA Region, 199720003
Benthic commun ly condition
High
Moderate
Low
Unsampled
Region 1
Region 2
Percent of estuarine area in each category
77
18
5
Region 3
Region 4
Region 6
Region 9
Region 10
All U.S.b
59 17
72
63 17
24
27
17 3
51
27
11
11
78
15
91
70
13
17
'Coverage Estuarine waters of the
contiguous 48 states and
Puerto Rico
bU S figures reflect the total sampled
area Unsampled areas were not
included in the calculation
Data source: U.S. EPA, 2004 (data
modified to report by EPA Region)
EPA Reg ons
The data for this indicator are from probabilistic
surveys conducted as part of EPA's National Coastal
Assessment (NCA) and presented in EPA's second
National Coastal Condition Report (U.S. EPA, 2004b).
The survey was designed to provide a national picture
of coastal benthic community condition by sampling
sites in estuarine waters throughout the contiguous 48
states and Puerto Rico. Each site was sampled once
during the period 1997-2000, within an index period
from July to September. The indicator reflects average
condition during this index period.
What the Data Show
Nationally, 70 percent of the sampled estuarine area
had a high benthic communities index score, with 13
percent in the moderate range and 17 percent scoring
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1 low (Exhibit 3-28). Condition varied somewhat by EPA Region, with high index scores ranging from 51
2 percent of the estuarine area in Region 6 to 91 percent in Region 10. Region 3 had the largest proportion
3 of estuarine area rated low (27 percent), while Region 10 had the lowest (4 percent). In the figure, the
4 portion of the estuarine area not represented by the sample is noted for each Region.
5 The National Coastal Condition Report found that many of the sites with low benthic community
6 condition also showed impaired water quality or sediment condition—which is not surprising given the
7 extent to which these stressors and effects are related. Of the 17 percent of national estuarine area rated
8 low on the benthic communities index, 38 percent also exhibited degraded sediment quality, 9 percent
9 exhibited degraded water quality (U.S. EPA, 2004), and 33 percent exhibited degraded sediment and
10 water quality.
11 Indicator Limitations
12 • The indicator does not include data from the Great Lakes, which are monitored using a
13 different index design. The coastal areas of Hawaii and a portion of Alaska have been
14 sampled, but the data had not yet been assessed at the time this indicator was compiled.
15 • Trend data are not yet available for this indicator. Because of differences in methodology, the
16 data presented here are not comparable with data that appeared in EPA's first National
17 Coastal Condition Report (NCCR I). The data presented here will serve as a baseline for
18 future surveys.
19 • Benthic indices for the Northeast, West, and Puerto Rico do not yet include measures of
20 pollution-tolerant or pollution-sensitive species. Although species diversity has the largest
21 impact on index scores in the other regions, index values could change in the future as these
22 components are added to the index values for these regions.
23 • Sample collection is limited to an index period from July to September. Further, because
24 benthic communities can be strongly influenced by episodic events, trawling, or climate
25 perturbations, this indicator may not reflect the full range of conditions that occur at each
26 sampling location throughout these months.
27 Data Sources
28 This indicator is based on an analysis published in EPA's National Coastal Condition Report II (U.S.
29 EPA, 2004). Summary data by EPA Region have not been published, but were provided by EPA's
30 National Coastal Assessment program. Underlying sampling data are housed in EPA's National Coastal
31 Assessment database (U.S. EPA, 2005) (http://www.epa.gov/emap/nca/html/data/index.html).
32 References
33 Engle, V.D., and J.K. Summers. 1999. Refinement, validation, and application of a benthic condition
34 index for northern Gulf of Mexico estuaries. Estuaries 22(3A):624-635.
35 Holland, A.F., A. Shaughnessy, and M.H. Heigel. 1987. Long-term variation in mesohaline Chesapeake
36 Bay benthos: spatial and temporal patterns. Estuaries 10:227-245.
37 Nixon, S.W., C.D. Hunt, and B.L. Nowicki. 1986. The retention of nutrients (C, N, P), heavy metals (Mn,
38 Cd, Pb, Cu), and petroleum hydrocarbons by Narragansett Bay. In: Lasserre, P., and J.M. Martin, eds.
39 Biogeochemical processes at the land-sea boundary. New York, NY: Elsevier. pp. 99-122.
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1 Sanders, H.L., J.F. Grassle, G.R. Hampson, L.S. Morse, S. Gerner-Price, and C.C. Jones. 1980. Anatomy
2 of an oil spill: long-term effects from the grounding of the barge Florida off West Falmouth,
3 Massachusetts. J. Mar. Res. 38:265-380.
4 U.S. EPA. 2005. EMAP national coastal database. Accessed 2005.
5
6 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
7
8 Weisberg, S.B., J.A. Ranasinghe, D.D. Dauer, L.C. Schnaffer, R.J. Diaz, and J.B. Frithsen. 1997. An
9 estuarine benthic index of biotic integrity (B-IBI) for Chesapeake Bay. Estuaries 20(1): 149-158
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INDICATOR: Submerged Aquatic Vegetation in the Chesapeake Bay
2 Submerged Aquatic Vegetation (SAV) is important to the Chesapeake Bay aquatic ecosystem. SAV
3 supports the Bay's health by:
4 • generating food and habitat for waterfowl, fish, shellfish and invertebrates;
5 • adding oxygen to the water column during photosynthesis;
6 • filtering and trapping sediment that otherwise would bury benthic organisms and cloud the
7 water column;
8 • inhibiting wave action that erodes shorelines; and
9 • absorbing nutrients, such as nitrogen and phosphorus, that otherwise could fuel the growth of
10 unwanted planktonic algae.
11 The loss of SAV from shallow waters of the Chesapeake Bay, which was first noted in the early 1960s, is
12 a widespread, well-documented problem (Batiuk et al., 2000). Review of aerial photographs taken from a
13 number of sites taken between the mid-1930s and the mid-1960s suggests that current SAV acreage is less
14 than half of that during the earlier period (Moore et al., 2004).
15 Trends in the distribution and abundance of SAV over time are useful in understanding trends in water
16 quality (Moore et al., 2004). Although other factors, such as climatic events and herbicide toxicity, may
17 have contributed to the decline of SAV in the Bay, the primary causes are eutrophication and associated
18 reductions in light availability (Batiuk et al., 2000). Like all plants, SAV needs sunlight to grow and
19 survive. Two key stressors that impact the growth of SAV are suspended sediments and excess nutrient
20 pollution. Suspended sediments—loose particles of clay and silt that are suspended in the water—make
21 the water dingy and block sunlight from reaching the plants. Similarly, excess nutrients in the water fuel
22 the growth of planktonic algae, which also block sunlight.
23 This indicator presents the distribution of SAV in the Chesapeake Bay and its tributaries from 1978 to
24 2005, as mapped from black and white aerial photographs. The surveys follow fixed flight routes to
25 comprehensively survey all shallow water areas of the Bay and its tidal tributaries. Non-tidal areas are
26 omitted from the survey. SAV beds less than 1 square meter in area are not included due to the limits of
27 the photography and interpretation. Annual monitoring began in 1978; however, no surveys were
28 conducted from 1979 to 1983 or in 1988. In years when the entire area could not be surveyed due to flight
29 restrictions or weather events, acreages in the non-surveyed areas were estimated based on prior years'
30 surveys.
31 What the Data Show
32 The extent of SAV in the Chesapeake Bay increased from 41,000 acres in 1978 to 78,000 acres in 2005
33 (Exhibit 3-29). The extent of SAV declined to a minimum of 38,000 acres in 1984 and the maximum
34 extent of SAV during this period was 90,000 acres, in 2002. The notable decline in SAV distribution
35 between 2002 and 2003 appears to be the result of substantial reductions in widgeongrass populations in
36 the lower and mid-bay regions. In addition to the large declines in widgeongrass, major declines in
37 freshwater SAV species occurred in the upper portion the Potomac River and Susquehanna region. While
38 populations of SAV appeared to be present in these segments very early in the growing season, persistent
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1 turbidity resulting from rain occurring throughout the spring and summer may have contributed to a very
2 early decline, well before Hurricane Isabel affected the Chesapeake Bay (Orth et al., 2004). The extent of
3 SAV gradually increased again through 2004 and 2005.
4 Indicator Limitations
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
There were no surveys in the years 1979-
1983 or in 1988.
The indicator includes some estimated
data for years with incomplete
photographic coverage. Spatial gaps in
1999 occurred due to the inability to
reliably photograph SAV following
hurricane disturbance. Spatial gaps in
2001 occurred due to flight restrictions
near Washington B.C. after the September
11th terrorist attacks. Other gaps occurred
in 2003 due to adverse weather in the
spring, summer, and fall (Hurricane
Isabel). Acreage in the non-surveyed areas
was estimated based on prior years'
surveys.
Photointerpretation methods changed over
the course of this study. However, data
have been adjusted to account for any
methodological inconsistencies.
Exhibit 3-29. Extent of submerged aquatic
vegetation (SAV) in the Chesapeake Bay,
1978-2005"
100
".
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1 Chesapeake Bay Program. 2006. Bay trends & indicators: bay grass abundance (baywide).
2
3 Moore, K.A., D.J. Wilcox, B. Anderson, T.A. Parham, and M.D. Naylor. 2004. Historical analysis of
4 SAV in the Potomac River and analysis of bay-wide historic SAV to establish a new acreage goal. Report
5 to EPA Chesapeake Bay Program.
6
7 Orth, R.J., D.J. Wilcox, L.S. Nagey, A.L. Owens, J.R. Whiting, and A. Serio. 2004. 2003 distribution of
8 submerged aquatic vegetation in Chesapeake Bay and coastal bays. Report to EPA Chesapeake Bay
9 Program,
10 VIMS. 2006. SAV distribution data archive. Virginia Institute of Marine Science. Accessed 2006.
11
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NDICATOR: Hypoxia in the Gulf of Mexico and Long Island Soui
2 Nutrient pollution is one of the most pervasive problems facing U.S. coastal waters, with more than half
3 of the nation's estuaries experiencing one or more symptoms of eutrophication (U.S. Commission on
4 Ocean Policy, 2004; NRC, 2000; Bricker et al., 1999). One symptom is low levels of dissolved oxygen
5 (DO), or hypoxia. Hypoxia can occur naturally, particularly in areas where natural physical and chemical
6 characteristics (e.g., salinity or mixing parameters) limit bottom-water DO. The occurrence of hypoxia in
7 shallow coastal and estuarine areas appears to be increasing, however, and is most likely accelerated by
8 human activities (Vitousek et al., 1997; Jickells, 1998).
9 This indicator tracks trends in hypoxia in the Gulf of Mexico and Long Island Sound, which are prime
10 examples of coastal and estuarine areas experiencing hypoxia. For consistency, this indicator focuses on
11 occurrences of DO below 2 mg/L, but actual thresholds for "hypoxia" and associated effects can vary
12 over time and space. Hypoxia often is defined as a concentration of DO below saturation, and because
13 saturation levels vary with temperature and salinity, the concentration that defines hypoxia will vary
14 seasonally and geographically. Effects of hypoxia on aquatic life also vary, as some organisms are more
15 sensitive to low DO than others. As a general rule, however, concentrations of DO above 5 mg/L are
16 considered supportive of marine life, while concentrations below this are potentially harmful. At about 3
17 mg/L, bottom fishes may start to leave the area, and the growth of sensitive species such as crab larvae is
18 reduced. At 2.5 mg/L, the larvae of less sensitive species of crustaceans may start to die, and the growth
19 of crab species is more severely limited. Below 2 mg/L, some juvenile fish and crustaceans that cannot
20 leave the area may die, and below 1 mg/L, fish totally avoid the area or begin to die in large numbers
21 (Howell and Simpson, 1994; U.S. EPA, 2000).
22 The Gulf of Mexico hypoxic zone on the Texas-Louisiana Shelf is the largest zone of coastal hypoxia in
23 the Western Hemisphere (CAST, 1999). It exhibits seasonally low oxygen levels as a result of
24 complicated interactions involving excess nutrients carried to the Gulf by the Mississippi and Atchafalaya
25 Rivers; physical changes in the river basin, such as channeling, construction of dams and levees, and loss
26 of natural wetlands and riparian vegetation; and the stratification in the waters of the northern Gulf caused
27 by the interaction of fresh river water and the salt water of the Gulf (CENR, 2000; Rabalais and Turner,
28 2001). Increased nitrogen and phosphorus inputs from human activities throughout the basin support an
29 overabundance of algae, which die and fall to the sea floor, depleting oxygen in the water as they
30 decompose. Fresh water from the rivers entering the Gulf of Mexico forms a layer of fresh water above
31 the saltier Gulf waters and prevents re-oxygenation of oxygen-depleted water along the bottom.
32 In Long Island Sound, seasonally low levels of oxygen usually occur in bottom waters from mid-July
33 though September, and are more severe in the western portions of the Sound, where the nitrogen load is
34 higher and stratification is stronger, reducing mixing and re-oxygenation processes (Welsh et al., 1991).
35 While nitrogen fuels the growth of microscopic plants that leads to low levels of oxygen in the Sound,
36 temperature, wind, rainfall, and salinity can affect the intensity and duration of hypoxia.
37 Data for the two water bodies are presented separately because they are collected through two different
38 sampling programs, each with its own aims and technical approach. The Gulf of Mexico survey is
39 designed to measure the extent of bottom-water hypoxia in the summer, with samples collected during a
40 cruise that generally occurs over a five-day period in mid-to-late July (LUMCON, 2006). Samples are
41 collected day and night along several transects designed to capture the overall extent of the hypoxic zone.
42 The number of locations varies from 60 to 90 per year, depending on the length of the sampling cruise,
43 the size of the hypoxic zone, logistical constraints, and the density of station locations. Long Island Sound
44 sampling is designed to determine both the maximum extent and the duration of hypoxia (Connecticut
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1 DEP, 2006a). Sampling is performed every month from October to May and every two weeks from June
2 to September at a set of fixed locations throughout the Sound. All Long Island Sound samples are
3 collected during the day.
Exhibit 3-30. Extent of dissolved oxygen less
than 2.0 mg/L in Gulf of Mexico bottom waters
in mid-summer, 1985-2005"
10,000
8,000
: 6,000
4,000
2,000
23
24
25
26
27
28
What the Data Show
The size of the midsummer bottom-water hypoxia area
(<2 mg/L DO) in the Northern Gulf of Mexico has
varied considerably since 1985, ranging from 40
square miles in 1988 (a drought year in the Mississippi
Basin) to approximately 8,500 square miles in 2002
(Exhibit 3-30). The unusually low areal extent in 2000
also was associated with very low discharge from the
Mississippi River (see the N and P Discharge from
Large Rivers indicator, p. 3-28). In the latest year of
sampling, 2005, the hypoxic zone measured over
4,500 square miles, slightly smaller than the state of
Connecticut (Exhibit 3-31). Over the full period of
record (1985-2005), the area with DO <2.0 mg/L has
averaged approximately 4,900 square miles.
The maximum extent and duration of hypoxic events
(<2 mg/L DO) in Long Island Sound also has varied
considerably since 1987 (Exhibit 3-32). Since 1987,
the largest area of DO less than 2 mg/L was 212
square miles, which occurred in 1994; the smallest area, 2 square miles, occurred in 1997 (panel A). The
shortest hypoxic event was 6 days in 1990 and the longest was 71 days, in 1989 (panel B). In 2005, the
latest year for which data are available, the maximum area and duration of DO <2 mg/L in Long Island
Sound were 95 square miles and 60 days, respectively, with the lowest DO levels occurring in the western
end of the Sound (Exhibits 3-32 and 3-33). Between 1987 and 2005, the average annual maximum was 71
square miles and 33 days.
I
'86 '88 '90 '92 '94 '96 '98 '00 '02 '04
Year
"Only 15 square miles were affected in 1988. No data were collected
in 1989.
Data source: Louisiana Universities Marine Consortium (LUMCON)
Exhibit 3-31. Dissolved oxygen less than 2 mg/L in Gulf of
Mexico bottom waters, July 24-29, 2005
Dissolved oxygen:
Less than 2 mg/L
Miles
•=
0 15 30 45 60 N
Data source: Louisiana Universities Marine Consortium (LUMCON)
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Indicator Limitations
1
2
3
4
5
6
7
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Exhibit 3-32. Maximum extent and duration
of dissolved oxygen less than 2.0 mg/L in
Long Island Sound bottom waters, 1987-2005
Gulf of Mexico
A. Extent of dissolved oxygen less than 2.0 mg/L
This indicator is based on a survey
conducted over a five-day period when
hypoxia is expected to be at its maximum
extent. The indicator does not capture
periods of hypoxia or anoxia (no oxygen
at all) occurring at times other than the
mid-summer surveys.
Because the extent of hypoxia is measured
through a single mid-summer sampling
cruise, duration cannot be estimated
250
200
1100
50
Off. iff.ff.ttffifttfrfi
'88 '90 '92 '94 '96 '98 '00 '02 '04
Year
This indicator does not track vertical
extent of hypoxia or anoxic volume.
Surveys usually end offshore from the
Louisiana-Texas State line; in years when
hypoxia extends onto the upper Texas
coast, the spatial extent of hypoxia is
underestimated.
B. Duration of dissolved oxygen less than 2.0 mg/L
Long Island Sound
80
60
40
20
'88 '90 '92 '94
Hypoxic or anoxic periods that may occur
between the two-week surveys are not
captured in the indicator.
'96 '98
Year
'00 '02 '04
Data source: Connecticut Department of Environmental Protection
(DEP), Long Island Sound Water Quality Monitoring Program
Samples are taken in the
daytime, approximately
one meter off the bottom.
This indicator does not
capture oxygen conditions
at night, which may be
lower because of the lack
of photosynthesis, or
conditions near the
sediment-water interface.
Exhibit 3-33. Dissolved oxygen in Long Island Sound bottom
waters, August 16-19, 2005
34 Data Sources
3 5 Gulf of Mexico data were provided by
36 the Louisiana Universities Marine
37 Consortium (LUMCON). Maps and
38 summary data from the most recent
39 Gulf of Mexico survey are published
40 online (LUMCON, 2006).
Dissolved oxygen:
• 0.0 -0.99 mg/L
§• 1.0 -1.99 mg/L
2.0-2.99 mg/L
3.0-3.49 mg/L
§•3.5-4.79 mg/L
• 4.8 +mg/L
Miles
=^H=
0 5 10 15 20 25
Data source: Connecticut Department of
Environmental Protection (DEP), Long Island Sound
Water Quality Monitoring Program
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1 Long Island Sound data were provided by the Connecticut Department of Environmental Protection's
2 Long Island Sound Water Quality Monitoring Program. Data on extent and duration of hypoxia have not
3 been published, but concentration maps are available online (Connecticut DEP, 2006b)—including the
4 2005 map shown in Exhibit 3-33.
5 References
6 Bricker, S.B., C.G. Clement, D.E. Pirhalla, S.P. Orlando, and D.R.G. Farrow. 1999. National
7 eutrophication assessment: effects of nutrient enrichment in the nation's estuaries. Silver Spring, MD:
8 NOAA National Ocean Service. 71 pp.
9 CAST (Council for Agricultural Science and Technology). 1999. Gulf of Mexico hypoxia: land and sea
10 interactions. Task force report no. 134.
11 CENR (Committee on Environment and Natural Resources). 2000. Integrated assessment of hypoxia in
12 the northern Gulf of Mexico. Washington, DC: National Science and Technology Council Committee on
13 Environment and Natural Resources.
14 Connecticut DEP (Department of Environmental Protection). 2006a. DEP monitors Long Island Sound.
15 Accessed 2006.
16 Connecticut DEP (Department of Environmental Protection). 2006b. The Long Island Sound Water
17 Quality Monitoring Program. Accessed 2006.
18 Howell, P., and D. Simpson. 1994. Abundance of marine resources in relation to dissolved oxygen in
19 Long Island Sound. Estuaries 17:394-402.
20 Jickells, T.D. 1998. Nutrient biogeochemistry of the coastal zone. Science 281:217-221.
21 LUMCON (Louisiana Universities Marine Consortium). 2006. Hypoxia in the northern Gulf of Mexico.
22 Accessed January 2006.
23 NRC (National Research Council). 2000. Clean coastal waters: understanding and reducing the effects of
24 nutrient pollution. Washington, DC: National Academy Press. 405 pp.
25 Rabalais, N.N., and R.E. Turner, eds. 2001. Coastal hypoxia: consequences for living resources and
26 ecosystems. Coastal and estuarine studies 58. Washington, DC: American Geophysical Union. 454 pp.
27 U.S. Commission on Ocean Policy. 2004. An ocean blueprint for the 21st century. Final report.
28 Washington, DC.
29 U.S. EPA. 2000. Ambient aquatic life water quality criteria for dissolved oxygen (saltwater): Cape Cod to
30 Cape Hatteras. EPA/822/R-00/12.
31 Vitousek, P.M., et al. 1997. Human alteration of the global nitrogen cycle: sources and consequences,
32 ecological applications. Ecol. Appl. 7(3):737-750.
33 Welsh, B.L., and F.C. Eller. 1991. Mechanisms controlling summertime oxygen depletion in western
34 Long Island Sound. Estuaries 14:265-278.
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INDICATOR:
Coastline
Harmful Algal Bloom Outbreaks Along the Western Florid
3 Harmful algal blooms (HABs) are "blooms" of large numbers of microscopic algae (phytoplankton) that
4 can harm humans or the environment, especially when they occur in near-shore coastal waters and
5 estuaries. HABs can be caused by a number of different species of phytoplankton. For example, in the
6 Gulf of Mexico, approximately 50 species of toxic or potentially toxic marine microalgae have been
7 identified (Fisher et al., 2003). HAB events along the Gulf coast are most commonly caused by the
8 phytoplankton organism Karenia brevis (a dinoflagellate), also known as "red tide." K. brevis can cause
9 massive fish kills, marine mammal mortality, and in humans can cause neurotoxic shellfish poisoning
10 (NSP) and respiratory irritation (NRC, 2000).
11 HABs can occur naturally, but some may be exacerbated by excess nutrients from terrestrial activities
12 (NRC, 2000). In the Gulf of Mexico, red tide events occur almost every year, generally in late summer or
13 early fall. The extent and duration of these blooms largely reflect the influence of winds, currents, and
14 other factors such as ocean mixing parameters. Red tide events in the Gulf typically last three to six
15 months and cover hundreds of square miles, although in extreme cases, blooms can last up to 18 months
16 and cover thousands of square miles (Haverkamp et al., 2004). K. brevis blooms tend to be concentrated
17 along the west coast of Florida and, to a lesser extent, along the Texas coast (HABSOS, 2004). These
18 events can impact ecological systems, fishing and shellfishing, and recreational activities in the Gulf of
19 Mexico. For example, severe red tide blooms in 1996 resulted in fish mortalities and beach and shellfish
20 bed closures throughout the Gulf, and killed over 150 endangered manatees along the Florida coast
21 (HABSOS, 2002).
22 This indicator reports the occurrence of elevated K. brevis concentrations along Florida's Gulf Coast,
23 where the Florida Fish and Wildlife Research Institute (FWRI) oversees an extensive red tide monitoring
24 network. FWRI and its partners (Mote Marine Laboratory, the University of South Florida, Collier
25 County, the Red Tide Offshore Monitoring Program, and others) maintain a set of permanent monitoring
26 sites from which they collect water samples at regular intervals for microscopic examination. When a
27 bloom is detected, researchers conduct additional targeted sampling to characterize the event. These
28 efforts are aided by NOAA satellite imagery, which is used to track the movement of blooms and to direct
29 targeted sampling.
30 For this indicator, K. brevis concentrations from FWRI's database were analyzed to determine the
31 probability of a sample exceeding 5,000 K. brevis cells per liter in any given month (Christman and
32 Young, 2006). At this concentration, the harvesting of shellfish in the area is prohibited (ISSC, 1999). For
33 reference, background levels of K. brevis in the Gulf of Mexico are approximately 1,000 cells per liter
34 year-round (Geesy and Tester, 1993). Although FWRI's database extends back as far as the 1950s, a
35 statistical review determined that prior to 2001, samples were not collected with sufficient regularity to
36 provide meaningful information about trends over time (Christman and Young, 2006). Therefore, this
37 indicator is restricted to the period 2001-2005. The analysis also was limited to a specific geographic area
38 with a high sampling density (map in Exhibit 3-34).
39 What the Data Show
40 Over the period of record (2001-2005), the probability of finding a K. brevis concentration above 5,000
41 cells per liter in a sample taken from the study area ranged from less than 5 percent to more than 70
42 percent, with both extremes occurring within the span of a few months in late 2001 and 2002 (Exhibit 3-
43 34). The graphic also suggests a seasonal pattern, with K. brevis counts peaking in late fall or early
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Exhibit 3-34. Karenia brevis counts above
5,000 cells per liter along the western Florida
coastline, 2001 -2005
2001 2002 2003 2004 2005
Each small tick mark represents one month
24
25
26
27
28
winter; this pattern is particularly well-defined in
2001 and 2002. There is no discernable trend from
year to year, however, and this period of record is
currently too short to provide information about
longer-term trends.
Indicator Limitations
These data are biased toward surface and
inshore sampling. The data do not
include blooms occurring well offshore.
This indicator does not include HABs
other than K. brevis.
Data Sources
Probability values were provided by the authors of a
statistical review of the Florida Fish and Wildlife
Research Institute (FWRI) database (Christman and
Young, 2006). This database can be accessed by
contacting FWRI (http://ocean.floridamarine.org/).
References
Christman, M., and L. Young. 2006. Analysis of
Karenia Brevis Gulf Data. Report to the Florida Fish
and Wildlife Research Institute.
(executive summary only)
Fisher, W.S., T.C. Malone, and J.D. Giattina. 2003. A pilot project to detect and forecast harmful algal
blooms in the northern Gulf of Mexico. Environ. Monit. Assess. 81(l-3):373-381.
Geesy, M., and P.A. Tester. 1993. Gymnodinium breve: ubiquitous in the Gulf of Mexico waters? In:
Smayda, T.J., and Y. Shimizu, eds. Toxic phytoplankton blooms in the sea. New York: Elsevier. pp. 251-
255.
29 HABSOS. 2004. An integrated case study for the Gulf of Mexico. Final report.
30 HABSOS. 2002. Prospectus: the Gulf of Mexico pilot project for a harmful algal blooms observing
31 system (HABSOS).
32 Haverkamp, D., K.A. Steidinger, and C.A. Heil. 2004. HAB monitoring and databases: the Florida
33 Karenia brevis example. In: Hall, S., S. Etheridge, D. Anderson, J. Kleindinst, M. Zhu, and Y. Zou, eds.
34 Harmful algae management and mitigation. APEC publication #204-MR-04.2. Singapore: Asia-Pacific
35 Economic Cooperation, pp. 102-109.
36 ISSC (Interstate Shellfish Sanitation Conference). 1999. National shellfish sanitation program: model
37 ordinance.
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1 NRC (National Research Council). 2000. Clean coastal waters: understanding and reducing the effects of
2 nutrient pollution. Washington, DC: National Academy Press. 405 pp.
3
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1 3.5.3 Discussion
2 What These Indicators Say About Trends in the Extent and Condition of
3 Coastal Waters and Their Effects on Human Health and the Environment
4 Extent
5 Although the ROE indicators do not characterize the extent of coastal waters, the Wetlands indicator (p.
6 3-53) shows that at least one type of coastal system has experienced changes in extent over the last half-
7 century. The number of acres of marine and estuarine wetlands has decreased overall since the 1950s,
8 although the rate of loss has slowed in recent years. While the indicator does not identify the exact
9 stressors responsible for the decline in marine and estuarine wetlands, it does list several factors that have
10 led to overall wetland loss, including development and conversion to deepwater. Section 3.4 provides
11 further detail on how human activities can affect wetland extent, including human activities that
12 exacerbate natural processes (e.g., storm damage). Ultimately, trends in wetland extent affect ecological
13 systems, as described further below.
14 Condition
15 Together, these indicators cover much of the spectrum of "condition," including four of the broad themes
16 introduced in Section 3.5.1: nutrients, toxic chemical contaminants, biotoxins, and the condition of native
17 populations and their habitat. As described in Section 3.5.1, excess nutrients can cause algal blooms that
18 result in low dissolved oxygen and reduced water clarity, which in turn can harm plant and animal
19 communities. For example, the Trophic State of Coastal Waters indicator (p. 3-62) shows elevated levels
20 of nutrients and chlorophyll-a (a surrogate for algal abundance) in a small but substantial portion of the
21 nation's estuarine areas. These results are consistent with indicators that show evidence of eutrophication,
22 such as decreased water clarity and hypoxia. The SAV in Chesapeake Bay indicator (p. 3-74) in turn
23 offers an example of an ecological effect linked to eutrophication. Nutrient stressors cannot be attributed
24 entirely to human activities; for example, the Gulf of Mexico hypoxic zone results in part from natural
25 mixing parameters, and trends in the extent of hypoxic zones show large year-to-year variations related to
26 factors like climate (Hypoxia in Gulf of Mexico and Long Island Sound indicator, p. 3-77). However, as
27 the spatial distribution of hypoxia in Long Island Sound suggests, the nation's coastal waters can
28 experience eutrophic effects that are very closely related to human activities (e.g., the location of a large
29 city). Further, as the SAV in Chesapeake Bay indicator (p. 3-74) shows, present conditions may be quite
30 different from historical reference conditions.
31 Overall, levels of toxic chemical contaminants are low in most of the nation's estuarine sediments, but as
32 the Coastal Sediment Quality indicator (p. 3-67) shows, condition can vary greatly from one region to the
33 next. In some EPA Regions, as much as 20 percent of estuarine area has sediments that either exceed
34 contamination reference standards or fail a screening test for benthic toxicity. Other indicators discuss the
35 extent to which toxic contaminants may be entering and affecting the food web. For example, benthic
36 communities—which are most directly impacted by contaminants in sediment—generally show little
37 evidence of disturbance (e.g., losses of pollution-sensitive species) (Coastal Benthic Communities
38 indicator, p. 3-71). However, fish tissues had at least one contaminant above human health guidelines in
39 22 percent of estuarine sampling sites (Coastal Fish Tissue indicator, p. 3-103), suggesting that
40 bioaccumulation of certain toxic compounds is widespread and, in some instances, could pose risks to
41 human health. This indicator suggests the importance of atmospheric deposition of mercury as a stressor
42 to coastal water condition, as well as historical activities that released PCBs and DDT into upstream and
43 coastal waters.
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1 The HAB Outbreaks in Western Florida indicator (p. 3-81) describes the pervasive nature of red tide,
2 which is one of many marine organisms that can produce dangerous biotoxins. As the data show, it is
3 common for red tide events in the eastern Gulf of Mexico to persist for two or more months of the year at
4 levels that trigger concerns about shellfish poisoning and associated human health effects (5,000 cells per
5 liter). In extreme cases, these events also can be harmful to ecosystems. As this indicator shows, the
6 condition of coastal waters with respect to HABs can vary greatly from year to year, depending on a
7 number of factors.
8 In more general ecological terms (populations, communities, and habitat), trends in the condition of
9 coastal waters vary. Benthic communities in the nation's estuaries are largely intact in terms of species
10 diversity (Coastal Benthic Communities indicator, p. 3-71), which is critical because these organisms are
11 a fundamental link in the coastal food web. Other populations, however, may be substantially lower than
12 historical levels as a result of human stressors—for example, the Chesapeake Bay's SAV, which is
13 vulnerable to changes in water clarity (SAV in Chesapeake Bay indicator, p. 3-74). SAV is ecologically
14 important because it is not just a plant population; it also provides habitat and facilitates nutrient cycling,
15 much like wetlands do. SAV has recently shown increases in extent, which may translate into increased
16 habitat and breeding grounds for various species. However, coastal habitat still continues to be threatened
17 by human stressors. As the Hypoxia in Gulf of Mexico and Long Island Sound indicator (p. 3-77) shows,
18 large areas of some of the nation's coastal water bodies are unsuitable for fish and shellfish populations
19 for at least a portion of the year.
20 Limitations, Gaps, and Challenges
21 Although the seven indicators discussed here provide a good overview of many important aspects of
22 coastal extent and condition, there are a few key limitations to their temporal and spatial coverage. For
23 example, the four indicators derived from the National Coastal Condition Report do not provide
24 information about trends over time, as there are insufficient data from previous surveys to compare with
25 recent data to examine potential trends.24 Another temporal limitation is that many surveys are conducted
26 during an index period, not over a full year; thus, they may not capture phenomena that occur outside the
27 sampling window.25 Spatially, the National Indicators are limited because they do not include data from
28 Alaska, Hawaii, and most U.S. territories. Alaska contains 75 percent of the bays, sounds, and estuarine
29 surface area in the United States, while Hawaii, the Caribbean, and the Pacific territories represent a set of
30 unique estuarine subsystems (i.e., coral reefs and tropical bays) that are not common in the contiguous 48
31 states.
32 One challenge in assessing coastal waters is that some aspects of condition vary naturally from one area
33 to another. For example, some rivers naturally carry a heavy load of sediments or nutrients into coastal
34 waters, while benthic community structure may depend on climate, depth, and geology. To assess coastal
35 waters with respect to natural background conditions, several of the ROE indicators use different
36 reference conditions for different regions.
24 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
25 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
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1 To assess the extent and condition of coastal waters more fully, it would help to have more information in
2 several key areas, including:
3 • More information about the extent of coastal waters—e.g., an indicator on coastal subsidence.
4 • Nationally consistent data on coastal water pollutants beyond those associated with trophic
5 state—for example, organics, toxics, metals, and pathogens.
6 • A National Indicator of invasive species, which are often transported from one area to another
7 along shipping routes or via aquaculture. Little information exists on a national level, in part
8 becauseofa lack of standard invasion metrics.
9 • Comprehensive information on the condition of the nation's coral reefs—a unique and fragile
10 habitat—and the status of coastal fish and shellfish communities.26
11
26 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
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1 3.6 WHAT ARE THE TRENDS IN THE QUALITY OF DRINKING WATER AND
2 THEIR EFFECTS ON HUMAN HEALTH?
3 3.6.1 Introduction
4 The average American consumes 1-2 liters of drinking water per day, including water used to make
5 coffee, tea, and other beverages.27 Virtually all drinking water in the United States comes from fresh
6 surface water and ground water. Large-scale water supply systems tend to rely on surface water resources
7 such as lakes, rivers, and reservoirs; these include the systems serving many large metropolitan areas.
8 Smaller systems are more likely to use ground water, particularly in regions with limited surface water
9 resources. Slightly more than half of the nation's population receives its drinking water from ground
10 water; i.e., through wells drilled into aquifers28 (including private wells serving about 15 percent of U.S.
11 households29). If drinking water contains unsafe levels of contaminants, this contaminated water can
12 cause a range of adverse human health effects. Among the potential effects are gastrointestinal illnesses,
13 nervous system or reproductive effects, and chronic diseases such as cancer.
14 Surface waters and aquifers can be contaminated by various agents, including microbial agents such as
15 viruses, bacteria, or parasites (e.g., E. coll, Cryptosporidium, or Giardia); chemical contaminants such as
16 inorganic metals, volatile organic compounds (VOCs), and other natural or manmade compounds; and
17 radionuclides, which may be manmade or naturally occurring. Contaminants also can enter drinking water
18 between the treatment plant and the tap (for example, lead can leach into water from old plumbing
19 fixtures or household or street-side pipes).
20 Drinking water contaminants can come from many sources:
21 • Human activities that contaminate the source. Aquifers and surface waters that provide
22 drinking water can be contaminated by many sources, as discussed in Sections 3.2 and 3.3.
23 For example, chemicals from disposal sites or underground storage facilities can migrate into
24 aquifers; possible contaminants include organic solvents (e.g., some VOCs), petroleum
25 products, and heavy metals. Contaminants can also enter ground water or surface water as a
26 result of their application to the land. Pesticides and fertilizer compounds (e.g., nitrate) can be
27 carried into lakes and streams by rainfall runoff or snowmelt, or percolate through the ground
28 and enter aquifers. Industrial wastes can contaminate drinking water sources if injected into
27 U.S. EPA. 1997. Exposure factors handbook. Volume I—general factors. EPA/600/P-95/002Fa. Washington, DC.
August.
28 U.S. Geological Survey. 1999. Ground water (general interest publication). Reston, VA.
29 U.S. EPA. 2002. The clean water and drinking water infrastructure gap analysis. EPA/816/R-02/020.
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1 containment wells or discharged into surface waters, as can mine waste (e.g., heavy metals) if
2 not properly contained.
3 • Natural sources. As ground water travels through rock and soil, it can pick up naturally
4 occurring contaminants such as arsenic, other heavy metals, or radionuclides. Some aquifers
5 are naturally unsuitable for drinking because the local geology happens to include high levels
6 of certain contaminants.
7 • Microbial pathogens. Human wastes from sewage and septic systems can carry harmful
8 microbes into drinking water sources, as can wastes from animal feedlots and wildlife. Major
9 contaminants include Giardia, Cryptosporidium, and E. coll O157:H7. Coliform bacteria
10 from human and animal wastes also may be found in drinking water if the water is not
11 properly finished; these bacteria may indicate that other harmful pathogens are present as
12 well.
13 • Treatment and distribution. While treatment can remove many chemical and biological
14 contaminants from the water, it may also result in the presence of certain disinfection
15 byproducts that may themselves be harmful, such as trihalomethanes. Finished water can also
16 become contaminated after it enters the distribution system, either from a breach in the
17 system or from corrosion of plumbing materials, particularly those containing lead or copper.
18 After water leaves the treatment plant, monitoring for lead in drinking water is done at the
19 tap, and monitoring for microbial contaminants (as well as disinfection byproducts) occurs
20 within the distribution system.
21 Chemical exposure through drinking water can lead to a variety of long- and short-term effects. Potential
22 health effects of exposure to certain metals, solvents, and pesticides can include chronic conditions such
23 as cancer, which can develop over long periods of time (up to 70 years). Higher doses over shorter
24 periods of time can result in a variety of biological responses, including toxicity, mutagenicity, and
25 teratogenicity (birth defects). Short-term results might include cosmetic effects (e.g., skin discoloration),
26 unpleasant odors, or more severe problems such as nervous system or organ damage, and developmental
27 or reproductive effects. The effects of some drinking water contaminants are not yet well understood. For
28 example, certain disinfection byproducts have been associated with cancer, developmental, and
29 reproductive risks, but the extent of this association is still uncertain.
30 Consuming water with pathogenic microbes can cause life-threatening diseases such as typhoid fever or
31 cholera—rare in the U.S. today—as well as more common waterborne diseases caused by organisms such
32 as Giardia, Cryptosporidium, E. coli, and Campylobacter. Health consequences of the more common
33 illnesses can include symptoms such as gastrointestinal distress (stomach pain, vomiting, diarrhea),
34 headache, fever, and kidney failure, as well as various infectious diseases such as hepatitis.
35 A number of factors determine whether the presence of contaminants in drinking water will lead to
36 adverse health effects. These include the type of contaminant, its concentration in the water, individual
37 susceptibility, the amount of contaminated water consumed, and the duration of exposure.
38 Disinfection of drinking water—the destruction of pathogens using chlorine or other chemicals—has
39 dramatically reduced the incidence of waterborne diseases such as typhoid, cholera, and hepatitis, as well
40 as gastrointestinal illness, in the United States. Other processes required depend on the physical,
41 microbiological, and chemical characteristics and the types of contaminants present in the source water
42 (e.g., filtration to remove turbidity and biological contaminants; treatment to remove organic chemicals
43 and inorganic contaminants such as metals; and corrosion control to reduce the presence of corrosion
44 byproducts such as lead at the point of use).
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1 3.6.2 ROE Indicators
2 This section presents an indicator that tracks trends in the total population served by community water
3 systems (CWS) for which states report no violations of health-based drinking water standards. Data for
4 this indicator come from EPA's Safe Drinking Water Information System, Federal Version. This system
5 houses all data submitted by states, EPA Regions, and the Navajo Nation Indian Tribe on the community
6 water systems they oversee.
7 Table 3.6.1. ROE Indicators of the Trends in the Quality of Drinking Water and their Effects on
8 Human Health
NATIONAL INDICATORS
Population Served by Community Water Systems with No Reported
Violations of Health-Based Standards (N/R)
LOCATION
3.6.2 -p. 3-90
9 N/R = National Indicator displayed at EPA Regional scale
10
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INDICATOR: Population Served by Community Water Systems with No Reported
Violations of Health-Based Standards
3 Community Water Systems (CWS), public water systems that supply water to the same population year-
4 round, served over 281 million Americans in fiscal year (FY) 2005 (U.S. EPA, 2006)—more than 90
5 percent of the U.S. population (U.S. Census Bureau, 2005). This indicator presents the percentage of
6 Americans served by CWS for which states reported no violations of EPA health-based standards for over
7 90 contaminants (U.S. EPA, 2004b).
8 Health-based standards include Maximum Contaminant Levels (MCLs) and Treatment Techniques (TTs).
9 An MCL is the highest level of a contaminant that is allowed in drinking water. A TT is a required
10 treatment process (such as filtration or disinfection) intended to prevent the occurrence of a contaminant
11 in drinking water (U.S. EPA, 2004c). TTs are adopted where it is not economically or technologically
12 feasible to ascertain the level of a contaminant, such as microbes, where even single organisms that occur
13 unpredictably or episodically can cause adverse health effects. Compliance with TTs may require finished
14 water sampling, along with quantitative or descriptive measurements of process performance to gauge the
15 efficacy of the treatment process. MCL-regulated contaminants tend to have long-term rather than acute
16 health effects, and concentrations vary seasonally (if at all; e.g., levels of naturally occurring chemical
17 contaminants or radionuclides in ground water are relatively constant). Thus, compliance is based on
18 averages of seasonal, annual, or less frequent sampling.
19 This indicator tracks the population served by CWS for which no violations were reported to EPA for the
20 period from FY 1993 to FY 2005, the latest year for which data are available. Results are reported as a
21 percentage of the overall population served by CWS, both nationally and by EPA Region. This indicator
22 also reports the number of persons served by systems with reported violations of standards covering
23 surface water treatment, microbial contaminants (microorganisms that can cause disease), and
24 disinfection byproducts (chemicals that that may form when disinfectants, such as chlorine, react with
25 naturally occurring materials in water and may pose health risks) (U.S. EPA, 2004b). The indicator is
26 based on violations reported quarterly by States, EPA, and the Navajo Nation Indian Tribe, who each
27 review monitoring results for the CWS that they oversee.
28 What the Data Show
29 Of the population served by CWS nationally, the percentage served by systems for which no health-based
30 violations were reported for the entire year increased from 79 percent in 1993 to 94 percent in FY 2002
31 before declining to 89 percent in FY 2005 (Exhibit 3-35). This indicator is based on reported violations of
32 the standards in effect in any given year. Several new standards went into effect after December 31, 2001.
33 These were the first new drinking water standards to take effect during the period of record (beginning in
34 1993). The results after FY 2002 would have been somewhat higher had it not been for violations of
35 standards that became effective in FY 2002 or after (Exhibit 3-35; see dark segment atop the last three
36 columns). As EPA adds to or strengthens its requirements for water systems over time, compliance with
37 standards comes to represent a higher level of public health protection.
38 When results are broken down by EPA Region, some variability over time is evident (Exhibit 3-36).
39 Between FY 1993 and FY 2005, most Regions were consistently above the national percentage. Three of
40 the Regions were substantially below the national average over much of the period of record, but as of FY
41 2005, only one Region remained well below the national percentage, largely because of a small number of
42 public water systems serving large populations.
43
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Exhibit 3-35. U.S. population served by Community Water
Systems with no reported violations of EPA health-based
standards, fiscal years 1993-2005a'b
8.
100
90
80
70
60
50
40
30
20
10
0
Percent served by systems
with no reported violations
of EPA standards that were
in effect as of 12/31/01.
Percent served by
systems with no reported
violations of any EPA
health-based standards in
place at the time.
'93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05 '06
Fiscal year
"Coverage: U.S. residents served by Community Water Systems (CWS) (approximately
95% of the total U.S. population).
bBased on reported violations of the standards in effect in any given year. Several new
standards went into effect after 12/31/01, including the Interim Enhanced Surface
Water Treatment Rule (CWS with surface water sources serving 10,000 or more
people) and the Disinfection Byproducts (DBP) Rule for CWS that disinfect. In FY2003,
the DBP rule applied to systems serving >10,000 people; as of January 2004, it applied
to all CWS. Data are presented for the first full fiscal year that the rules were in effect.
Data source: U.S. EPA, Safe Drinking Water Information System, Federal Version
Exhibit 3-36. U.S. population served by
Community Water Systems with no reported
violations of EPA health-based standards, by
EPA Region, fiscal years 1993-2005""
100
c
o
IBO
60
40
20
-R1
-R2
-R3
-R4
-R5
R6
R7
R8
-R9
-R10
-Nat'l
'93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05 '06
Fiscal year
"Coverage: U.S. residents served
by Community Water Systems
(CWS) (approximately 95% of
the total U.S. population).
bBased on reported violations of
the standards in effect in any
given year.
Data source: U.S. EPA, Safe
Drinking Water Information System, Federal Version
2 In FY 2005, reported violations involving surface water treatment rules in large CWS were responsible
3 for exceeding health-based standards for more than 14 million people (5 percent of the population served
4 by CWS nationally) (Exhibit 3-37). Reported violations of heath-based coliform standards affected 11.6
5 million people (4.1 percent of the CWS-served population), and reported violations of the health-based
6 disinfection byproducts standards (Stage 1) affected nearly 6 million people (2.1 percent of the CWS-
7 served population). Overall, of the 11.5 percent of the population served by systems with reported
8 violations in FY 2005, 85 percent of these cases involved at least one of these three rules governing
9 treatment to prevent waterborne diseases—the most widespread and acute threat to health from drinking
10 water—or the contaminants created by such treatment.
11 Indicator Limitations
12
13
14
15
16
Non-community water systems (typically relatively small systems) that serve only transient
populations such as restaurants or campgrounds, or serving those in a non-domestic setting
for only part of their day (e.g., a school, religious facility, or office building), are not included
in population served figures.
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Exhibit 3-37. U.S. population served by
Community Water Systems with reported
violations of EPA health-based standards, by
type of violation, fiscal year 2005"
Percent of
CWS-served
population
11.5
2.1
5.0
33
34
35
36
37
38
39
40
41
42
43
Population served
Any violation
Selected violations
Stage 1 Disinfection
Byproducts Rule
Surface Water
Treatment Rules
32,485,318
5,967,270
14,161,702
Total Coliform Rule 11,576,743
Any of these
selected rules"
27,676,881
1 Coverage: U.S. residents served by Community Water Systems
(CWS) (approximately 95% of the total U.S. population).
11 Some CWS violated more than one of the selected rules.
Data source: U.S. EPA, Safe Drinking Water Information System
Federal Version
Domestic (home) use of drinking water
supplied by private wells—which serve
approximately 15 percent of the U.S.
population (USGS, 2004)—is not
included.
Bottled water, which is regulated by
standards set by the Food and Drug
Administration, is not included.
National statistics based on population
served can be volatile, because a single
very large system can sway the results by
up to 2 to 3 percent; this effect becomes
more pronounced when statistics are
broken down at the regional level, and
still more so for a single rule.
Some factors may lead to overstating the
extent of population receiving water that
violates standards. For example, the
entire population served by each system
in violation is reported, even though only
part of the total population served may
actually receive water that is out of
compliance. In addition, violations stated
on an annual basis may suggest a longer
duration of violation than may be the
case, as some violations may be as brief
as an hour or a day.
Other factors may lead to understating the population receiving water that violates standards.
CWS that purchase water from other CWS are not always required to sample for all
contaminants themselves, and the CWS that are wholesale sellers of water generally do not
report violations for the population served by the systems that purchase the water.
Under-reporting and late reporting of violations by states to EPA affect the ability to
accurately report the national violations total. EPA estimated that between 1999 and 2001,
states were not reporting 35 percent of all health-based violations, which reflects a sharp
improvement in the quality of violations data compared to the previous three-year period
(U.S. EPA, 2004a). In late 2006, EPA expects to issue an updated estimate of data quality for
the period 2002-2004.
State data verification and other quality assurance analyses indicate that the most widespread
data quality problem is under-reporting of monitoring and health-based violations and
inventory characteristics. Under-reporting occurs most frequently in monitoring violations;
even though these are separate from the health-based violations covered by the indicator,
failures to monitor could mask violations of TTs and MCLs.
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1 Data Sources
2 Data for this indicator were obtained from EPA's Safe Drinking Water Information System (U.S. EPA,
3 2006) (http://www.epa. gov/safewater/data/getdata.html:
4 http://www.epa.gov/safewater/data/pivottables.html). This database contains a record of violations
5 reported to EPA by the states or other entities that oversee Community Water Systems, along with annual
6 summary statistics.
7 References
8 U.S. Census Bureau. 2005. Annual population estimates 2000 to 2005. Released December 22, 2005.
9 Washington, DC. Available from
10
11 U.S EPA. 2006. Safe Drinking Water Information System, Federal Version. Accessed July 2006.
12
13 U.S. EPA. 2004a. Safe Drinking Water Act 30th anniversary fact sheet: drinking water monitoring,
14 compliance, and enforcement.
15
16 U.S. EPA. 2004b. Safe Drinking Water Act 30th anniversary fact sheet: drinking water standards and
17 health effects,
18 U.S. EPA. 2004c. Safe Drinking Water Act 30th anniversary fact sheet: glossary.
19
20 USGS (U.S. Geological Survey). 2004. Estimated use of water in the United States in 2000. 2004
21 revision,
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1 3.6.3 Discussion
2 What This Indicator Says About Trends in the Quality of Drinking Water and
3 Their Effects on Human Health
4 Most Americans served by CWS are served by facilities with no reported violations (Drinking Water
5 indicator, p. 3-90). Since 1993, the percentage of Americans served by community water systems for
6 which states reported no health-based violations has increased, although there has been some reversal
7 nationally since the percentage peaked in 2002. While there have been noticeable differences among EPA
8 Regions over the period of record, most Regions have been consistently above 90 percent since 1993.
9 Only one Region has been consistently below the national average, though according to the data source,
10 this result is due largely to one large metropolitan water system which is under a legal settlement to
11 upgrade its treatment technology. As this result suggests, while the nation has thousands of community
12 water systems, a substantial percentage of the population depends on the quality of a small number of
13 large metropolitan water systems.
14 Limitations, Gaps, and Challenges
15 As noted in the indicator description, a challenge in assessing national drinking water quality is that there
16 are inherent limitations in using reporting data. Some violations may be unreported, particularly if
17 monitoring is inadequate—leading to undercounting. Other violations may be overlooked because CWS
18 may purchase water from other CWS and not test it for all contaminants themselves. Conversely, the data
19 could also overstate the portion of the population receiving water in violation of standards, because a
20 violation could be as short as an hour or a day and be limited to water received by only a small portion of
21 a system' s customers.
22 Other challenges relate to the interpretation of the Drinking Water indicator (p. 3-90). For example, trends
23 can be confounded by the fact that water quality standards and treatment requirements change over time.
24 Thus, an apparent increase in violations over time may result from new or more stringent MCLs rather
25 than simply a decline in the quality of drinking water, as these new requirements may also affect some
26 systems' compliance with existing standards.
27 As described in the indicator summary, the indicator does not address the quality of drinking water other
28 than that obtained from CWSs. Information that would provide a more complete characterization of
29 drinking water quality include National Indicators for:
30 • Trends in drinking water quality from CWS that did have reported violations. The
31 Drinking Water indicator does not explain the nature of every reported violation; nor does it
32 show how many contaminants may be above standards, the identity of the contaminants, the
33 extent to which standards were exceeded, or the duration of the violations (some of which,
34 especially in larger systems, were only a very few hours in length).
35 • The quality of drinking water from other public water systems. There is no ROE
36 indicator for drinking water quality from transient and non-transient non-community water
37 systems, which are required to monitor quality and report violations to state authorities, but
38 are regulated only for certain contaminants.
39 • The quality of drinking water from non-public water supplies. Private wells, cisterns, and
40 other non-public water supplies are not subject to federal regulation. Some private supplies
41 are treated, and some people do test their private water for common contaminants. However,
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1 no national infrastructure, and few if any systematic state efforts, currently exist to collect
2 data on trends in the quality of these supplies. Bottled water is regulated by the Food and
3 Drug Administration (FDA), which is required by law to apply standards that are no less
4 stringent or protective of public health than EPA's, but there is no ROE indicator on the
5 quality of bottled water.
6 In addition to these gaps, there are no ROE indicators to identify trends in health effects of interest, such
7 as waterborne disease occurrence. Data are very limited for endemic waterborne illness as well as for
8 acute waterborne disease outbreaks.
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1 3.7 WHAT ARE THE TRENDS IN THE CONDITION OF RECREATIONAL WATERS
2 AND THEIR EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT?
3 3.7.1 Introduction
4 The nation's rivers, lakes, and coastal waters are used for many different forms of recreation. Some
5 recreational activities take place in or on the water, such as swimming, boating, Whitewater rafting, and
6 surfing. Other activities may not involve contact with the water yet may still require water—or be
7 enhanced by proximity to water. Examples include a picnic at the beach, hiking, nature viewing (e.g., bird
8 watching), and hunting (especially waterfowl). People also engage in fishing and shellfishing as
9 recreational activities.
10 In the questions on fresh surface waters and coastal waters (Sections 3.2 and 3.5), condition is defined as
11 a combination of physical, chemical, and biological attributes of a water body. For recreational waters,
12 condition is more specific, focusing on those physical, chemical, and biological attributes that determine a
13 water body's ability to support recreational activities. The particular attributes necessary to support
14 recreation vary widely, depending on the nature of the activity in question. In a more general sense,
15 however, the components of recreational condition fall into two main categories:
16 • Attributes that determine whether recreational activities can be enjoyed without unacceptable
17 risk to human health—primarily pathogens and chemical contaminants that can affect the
18 health of humans who are exposed during contact activities such as swimming.
19 • Attributes associated with ecological systems that support recreation—e.g., the status offish
20 and bird communities, as well as chemical and physical characteristics that may affect these
21 populations and their habitat. These attributes also contribute to the aesthetic qualities
22 important for recreational activities.
23 Many stressors affecting the condition of recreational waters fall into the broad category of contaminants.
24 This category includes chemical contaminants, various pathogens (viruses, bacteria, and other parasites or
25 protozoans) that can cause infectious disease, and pollutants such as trash or debris. These stressors can
26 come from a variety of point sources and nonpoint sources, and can be discharged or washed directly into
27 recreational waters or carried downstream to lakes or coastal areas. Among the major sources are storm
28 water and sediment runoff, direct discharge (e.g., from industrial facilities and sewer systems),
29 atmospheric deposition, and recreational activities themselves (e.g., outboard motor exhaust and
30 overboard discharge of sanitary wastes). Some chemicals and pathogens occur naturally, but their
31 abundance may be influenced by other human stressors such as land use and land cover (e.g., paved
32 surfaces and forestry and irrigation practices, which can influence runoff patterns) or by natural stressors
33 such as weather and climate. Land use and land cover can influence recreational condition in other ways
34 as well.
35 In terms of human health, the stressors that pose the greatest potential risks are chemical and biological
36 contaminants. People can be exposed to these contaminants if they swim in contaminated waters or near
37 storm water or sewage outfall pipes—especially after a rainfall event. Boating also may pose risks of
38 exposure, although to a lesser extent. For toxic chemical contaminants, the main routes of exposure are
39 through dermal (skin) contact or accidental ingestion. For pathogens, the main route of exposure is by
40 swallowing water, although some infections can be contracted simply by getting polluted water on the
41 skin or in the eyes. In some cases, swimmers can develop illnesses or infections if an open wound is
42 exposed to contaminated water.
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1 Effects of exposure to chemical and biological contaminants range from minor illnesses to potentially
2 fatal diseases. The most common illness is gastroenteritis, an inflammation of the stomach and the
3 intestines that can cause symptoms such as vomiting, headaches, and diarrhea. Other minor illnesses
4 include ear, eye, nose, and throat infections. While unpleasant, most swimming-related illnesses are
5 indeed minor, with no long-term effects. However, in severely contaminated waters, swimmers can
6 sometimes be exposed to serious and potentially fatal diseases such as meningitis, encephalitis, hepatitis,
7 cholera, and typhoid fever.30 Children, the elderly, and people with weakened immune systems are most
8 likely to develop illnesses or infections after coming into contact with contaminated water.
9 From an ecological perspective, stressors to recreational waters can affect habitat, species composition,
10 and important ecological processes. For example, changes in land cover (e.g., the removal of shade trees)
11 may cause water temperature to rise above the viable range for certain fish species. Hydromodifications
12 such as dams may create some recreational opportunities (e.g., boating), but they also may impede the
13 migration offish species such as salmon. Chemical and biological contaminants may harm plants and
14 animals directly, or they may disrupt the balance of the food web. For example, acid deposition may lead
15 to acidification in lakes, while excess nutrients can lead to eutrophic conditions such as low levels of
16 dissolved oxygen, which in turn can harm fish and shellfish populations. Beyond their obvious effects on
17 activities like fishing and nature viewing, stressors such as these also can be detrimental to recreational
18 activities in a more aesthetic sense, as the presence of dead fish or visibly unhealthy plants may diminish
19 one' s enj oyment of recreation in or near the water.
20 Ultimately, ecological effects can also impact human health. For example, eutrophic conditions can
21 encourage harmful algal blooms (HAB)—some of which can produce discomfort or illness when people
22 are exposed through ingestion or skin or eye contact. One well-known type of F£AB is "red tide," which in
23 humans can cause neurotoxic shellfish poisoning (NSP) and respiratory irritation.31
24 3.7.2 ROE Indicators
25 At this time, no National Indicators have been identified to quantify the condition of recreational waters.
26 Individual states monitor certain recreational waters for a set of indicator bacteria and report monitoring
27 results to EPA. However, the methodology and frequency of data collection vary among states, so the
28 data are not necessarily comparable.
29 Challenges and information gaps for developing reliable National Indicators of recreational water
30 condition are described in more detail in Section 3.7.3 below.
30 Pond, K. 2005. Water recreation and disease—plausibility of associations, sequelae and mortality. Published on
behalf of World Heath Organization. London, United Kingdom: IWA Publishers.
31 National Research Council. 2000. Clean coastal waters: understanding and reducing the effects of nutrient
pollution. Washington, DC: National Academy Press. 405 pp.
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1 3.7.3 Discussion
2 Limitations, Gaps, and Challenges
3 Several challenges exist in assessing the condition of the nation's recreational waters. Foremost is the lack
4 of a comprehensive national system for collecting data on pathogen levels at beaches, a key concern in
5 assessing the suitability of recreational waters with respect to human health. In addition, data on the types
6 and extent of health effects associated with swimming in contaminated water are limited. The number of
7 occurrences is likely under-reported because individuals may not link common symptoms (e.g.,
8 gastrointestinal ailments, sore throats) to exposure to contaminated recreational waters.
9 Another challenge to answering this question is the breadth of the subject. "Recreation" encompasses a
10 wide range of activities, involving different types of water bodies and entailing varying concepts of
11 condition. While the recreational condition of a Whitewater stream with a native salmon population will
12 be determined largely by flow levels and condition offish habitat, for example, the recreational condition
13 of a beach will be assessed more in terms of levels of pathogens and chemical contaminants.
14 Gaps in assessing the condition of the nation's recreational waters include National Indicators of pathogen
15 levels in recreational waters (rivers, lakes, and coastal beaches), the magnitude of specific stressors—
16 particularly contaminant loadings (biological and chemical)—to recreational waters, harmful algal
17 blooms (HABs) in recreational waters, and the condition of recreational fish and shellfish populations.
18
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1 3.8 WHAT ARE THE TRENDS IN THE CONDITION OF CONSUMABLE FISH AND
2 SHELLFISH AND THEIR EFFECTS ON HUMAN HEALTH?
3 3.8.1 Introduction
4 Fish and shellfish caught through commercial, recreational, or subsistence fishing are an important part of
5 a healthful diet for many people. Fish and shellfish contain high-quality protein and other essential
6 nutrients, are low in saturated fat, and contain omega-3 fatty acids. Most fish consumed in the United
7 States is commercial fish, purchased in supermarkets or fish stores. Fishing also is one of the most
8 popular outdoor recreational activities in the country, with more than 34 million people per year fishing
9 recreationally32—many of whom eat at least some of the fish they catch. In addition, subsistence fishers—
10 people who rely on fish as an affordable food source or for whom fish are culturally important—consume
11 fish and shellfish as a major part of their diets. Commercial, recreational, and subsistence fisheries all
12 have substantial economic value for the nation, regions, and local communities.
13 Americans consume fish and shellfish caught in the nation's lakes, rivers, and estuaries and in deep ocean
14 fisheries, as well as farmed fish and shellfish. Some of these fish and shellfish contain elevated levels of
15 chemical or biological contaminants. This question addresses the condition of consumable fish and
16 shellfish caught or farmed in the United States—whether, and the extent to which, these organisms
17 contain contaminants that could affect the health of people who consume them.
18 According to recent surveys, the average American consumes close to 13 grams offish and shellfish per
19 day (prepared weight), which amounts to slightly more than one 3-ounce serving per week.33 However,
20 many Americans consume substantially more fish and shellfish than the national average; some of the
21 highest consumption rates are among tribal and ethnic populations who fish for subsistence. Concern
22 about fish and shellfish safety is higher for these groups as well as for children, pregnant and nursing
23 women (because of possible effects on the fetus or infant), and other population subgroups who may be
24 more vulnerable to the health effects of certain chemical or biological contaminants (e.g., elderly or
25 immunosuppressed individuals).
26 Chemical contaminants of greatest concern in consumable fish and shellfish tend to be those that are
27 persistent, bioaccumulative, and toxic (called PBTs). These chemicals can persist for long periods in
28 sediments and then enter the food web when ingested by bottom-dwelling (benthic) organisms. Benthic
29 organisms are eaten by smaller fish, which in turn are eaten by larger fish, which may be consumed by
30 humans or wildlife. PBTs that are common in fresh and coastal waters include:
31 • Mercury. This highly toxic metal is present in waters all over the globe—a result oflong-
32 range transport and deposition of airborne mercury as well as direct inputs to water.34
33 Mercury in water bodies can be methylated by certain bacteria in bottom sediments to form
32 U.S. Department of the Interior, Fish and Wildlife Service, and U.S. Department of Commerce, U.S. Census
Bureau. 2002. 2001 national survey of fishing, hunting, and wildlife-associated recreation.
33 U.S. EPA. 2002. Estimated per capita fish consumption in the United States. EPA/821/C-02/003. Washington,
DC.
34 U.S. and global sources of mercury are described in more detail in Section 2.2, which includes an indicator of
domestic mercury emissions.
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1 methylmercury, which is more toxic and bioavailable than other forms of mercury.35 It also is
2 biomagnified through aquatic food webs, so that it becomes particularly concentrated in
3 larger and longer-lived predators such as bass, tuna, swordfish, and some sharks. Exposure to
4 high levels of methylmercury can cause reproductive and other effects in wildlife;36 in
5 humans, exposure to elevated levels is primarily associated with developmental and
6 neurological health effects.37
7 • Polychlorinated biphenyls (PCBs) and the pesticide DDT. Though PCBs and DDT are no
8 longer manufactured or used in the U.S., they persist in historical deposits in watersheds and
9 near-shore sediments, which can continue to contaminate fish and shellfish. These chemicals
10 are also circulated globally as a result of use in other parts of the world. Levels of PCBs and
11 DDT are a concern in some bottom-feeding fish and shellfish, as well as in some higher-level
12 predators. These chemicals have been linked to adverse health effects such as cancer, nervous
13 system damage, reproductive disorders, and disruption of the immune system in both humans
14 and wildlife.
15 Other chemical contaminants that may be present in fish and shellfish include other pesticides, metals
16 (such as arsenic), and dioxins and furans.38
17 Biological contamination also can affect the condition offish and shellfish—particularly the latter. For
18 example, shellfish contaminated with pathogens from human and animal fecal wastes can cause
19 gastrointestinal illness and even death in individuals with compromised immune systems. Sources of fecal
20 contamination in shellfish include urban runoff, wildlife, wastewater treatment systems and treatment
21 plants, agricultural runoff, and boating and marinas.
22 Marine biotoxins produced by certain types of algae can contaminate fish and shellfish as well. These
23 toxins not only can harm fish and fish communities—sometimes resulting in massive fish kills or losses
24 to aquaculture operations—but they also can make their way through the food web to affect seabirds,
25 marine mammals, and humans. Mollusks such as mussels, clams, oysters, whelks, and other shellfish can
26 carry biotoxins that have common symptoms such as irritation of the eyes, nose, throat, and tingling of
27 the lips and tongue. Consumption of contaminated seafood can cause a range of other health effects in
28 humans, depending on the organism involved, including gastrointestinal illness, amnesia, memory loss,
29 paralysis, and even death.39'40
35 U.S. EPA. 1997. Mercury study report to Congress. Volume III: fate and transport of mercury in the environment.
EPA/452/R-97/005.
36 U.S. EPA. 1997. Mercury study report to Congress. Volume V: health effects of mercury and mercury
compounds. EPA/452/R-97/007.
37 National Research Council. 2000. lexicological effects of methylmercury. Washington, DC: National Academies
Press.
38 U.S. EPA. In progress. National study of chemical residues in lake fish tissue. Washington, DC.
39 Baden D., L.E. Fleming, and J.A. Bean. 1995. Marine toxins. In: DeWolff, F.A., ed. Handbook of clinical
neurology: intoxications of the nervous system, part II: natural toxins and drugs. Amsterdam, The Netherlands:
Elsevier Press, pp. 141-175.
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1 The growth of aquaculture, or fish farming, may affect the levels of certain contaminants in consumable
2 fish and shellfish. Dense colonies can increase stress and disease transmission among fish, in some cases
3 requiring the administration of antibiotics.41 Studies have also found higher levels of certain contaminants
4 in farmed fish than in their wild counterparts, possibly due to differences in diet. For example, several
5 studies have found higher concentrations of PCBs, organochlorine pesticides, and polybrominated
6 diphenyl ethers (PBDEs) in farmed salmon.42
7 Overfishing also can affect the condition offish—not only the species being fished, but also the species
8 that prey on them—by disrupting the food web. Because of depleted food sources, predators can become
9 more susceptible to disease (such as infection of rockfish by mycobacterial lesions). These infections are
10 often confined to internal organs and may not be apparent to anglers, although in some cases they are
11 associated with external sores as well. Some types of mycobacteria can also infect humans who handle
12 diseased fish if the infection comes into contact with an open wound. The slow-developing infections are
13 usually not severe in humans, but in some cases they can cause major health problems, especially in
14 people with compromised immune systems.
15 3.8.2 ROE Indicators
16 Two ROE indicators characterize levels of chemical contaminants in edible fish and shellfish species.
17 One indicator reports levels and occurrence of contaminants in fish in estuarine areas; the other, in
18 freshwater lakes and reservoirs. Both indicators are based on nationwide probabilistic surveys.
19 The coastal fish indicator is based on an index originally presented in EPA's second National Coastal
20 Condition Report (NCCRII). The underlying data were collected between 1997 and 2000 as part of
21 EPA's Environmental Monitoring and Assessment Program (EMAP). EMAP's probabilistic coastal
22 surveys are designed to be representative of 100 percent of estuarine acreage in the contiguous 48 states.
23 This indicator presents results by EPA Region.
24 The other indicator describes contamination offish in inland lakes. This indicator is derived from fish
25 samples collected and analyzed for EPA's National Study of Chemical Residues in Lake Fish Tissue, a
26 probabilistic survey designed to estimate the national distribution of the mean levels of selected
27 persistent, bioaccumulative, and toxic chemical residues in fish tissue from lakes and reservoirs.
28 Note that this question does not rely on information about fish and shellfish consumption advisories.
29 While many states and tribes issue fish consumption advice and develop fish advisory programs, there is
30 great variability in how monitoring is conducted, how decisions are made to place waters under advisory,
31 and what specific advice is provided when contamination is found in fish. Further, trends in the number of
40 Van Dolah, P.M. 2000. Marine algal toxins: origins, health effects, and their increased occurrence. Environ.
Health Persp. 108(Suppl 1):133-141.
41 Barton, B. A., et al. 1991. Physiological changes in fish from stress in aquaculture with emphasis of the response
and effects of corticosteroids. Annu. Rev. FishDis. 1:3-26.
42 Easton, M.D.L., D. Luszniak, and E. Von der Geest. 2002. Preliminary examination of contaminant loadings in
farmed salmon, wild salmon and commercial salmon feed. Chemosphere 46(7): 1053-1074.
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1 advisories over time may reflect changes in the frequency and intensity of monitoring.43 Thus, fish
2 advisories cannot provide a consistent national metric for trends in the condition of consumable fish and
3 shellfish.
4 Table 3.8.1. ROE Indicators of the Trends in the Condition of Consumable Fish and Shellfish and
5 their Effects on Human Health
NATIONAL INDICATORS
Coastal Fish Tissue Contaminants (N/R)
Contaminants in Lake Fish Tissue
LOCATION
3.8.2- p. 3-103
3.8.2- p. 3-107
6 N/R = National Indicator displayed at EPA Regional scale
7
43 U.S. EPA. 2005. Fact sheet: national listing offish advisories. EPA/823/F-05/004.
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INDICATOR: Coastal Fish Tissue Contaminants
2 Contaminants in fish not only affect their own health and ability to reproduce, but also affect the many
3 species that feed on them. Contaminants also may make fish unsuitable for human consumption (U.S.
4 EPA, 2000).
5 This indicator, derived from an indicator presented in EPA's second National Coastal Condition Report
6 (NCCRII) (U.S. EPA, 2004), is based on National Coastal Assessment (NCA) fish tissue survey data
7 from 653 estuarine sites throughout the United States. The survey was designed to provide a national
8 picture of coastal fish tissue contaminants by sampling sites in estuarine waters throughout the contiguous
9 48 states. Each site was sampled once during the period 1997-2000, within an index period from July to
10 September. The indicator reflects average condition during this index period.
11 Fish and shellfish analyzed in the survey included Atlantic croaker, white perch, catfish, flounder, scup,
12 blue crab, lobster, shrimp, whiffs, mullet, tomcod, spot, weakfish, halibut, sole, sculpins, sanddabs, bass,
13 and sturgeon. At each site, five to ten whole-body fish samples were tested for 90 contaminants, 16 of
14 which have EPA-established risk guidelines for recreational fishers. This indicator is based on data
15 collected from 1997 to 2000.
16 To assess risks to human health, contaminant concentrations in fish tissue were compared with
17 established EPA guidelines based on the consumption of four 8-ounce fish meals per month (U.S. EPA,
18 2000, 2004). For most contaminants this is done using whole body concentrations, but for mercury, which
19 concentrates in the edible fillet portion of the fish, a factor of 3.0 was used to correct whole-body
20 concentrations in order to approximate fillet concentrations. The factor, 3.0, represents the median value
21 (range 1.5-5.0) found in the available literature (Windom and Kendall, 1979; Mikac et al., 1985; Schmidt
22 and Brumbaugh, 1990; Kannan et al., 1998; Canadian Council of Ministers of the Environment, 1999).
23 For this indicator, a site was given a high score if one or more contaminants were present at a
24 concentration above the guideline ranges. A site was rated moderate if one or more contaminants were
25 within the guideline ranges but none was in exceedance. Sites with all contaminants below their guideline
26 ranges were given a low contamination score.
27 What the Data Show
28 Nationwide, 63 percent of sites showed low fish tissue contamination, 15 percent had moderate
29 contamination, and 22 percent exhibited high contamination (Exhibit 3-38). Fish tissue contamination
30 varied notably from one EPA Region to the next; for example, the percentage of sites with low
31 contamination ranged from 25 percent (Region 1) to 83 percent (Region 4). Regions 2 and 9 had the
32 largest proportion of sites with high contamination (41 percent and 40 percent, respectively).
33 Data from EPA's EMAP National Coastal Database showed that nationwide, PCBs were the
34 contaminants most frequently responsible for high fish tissue contamination, with 19 percent of sites
35 above EPA guidelines (Exhibit 3-39). Other chemicals present above EPA guidelines at many sites were
36 mercury in muscle tissue (18 percent of sites), DDT (8 percent), and PAHs (3 percent) (Exhibit 3-39).
37 Inorganic arsenic, selenium, chlordane, endosulfan, endrin, heptachlor epoxide, hexachlorobenzene,
38 lindane, and Mirex were below EPA guidelines for all fish sampled in the NCA.
39
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Exhibit 3-38. Coastal fish tissue contaminants
in the contiguous U.S. by EPA Region,
1997-2000a'b
Level of contamination:
Low
Moderate
High
Percent of estuarine sites in each category:
Region 1
Region 2
Region 3
Region 4
Region 6
Region 9
Region 10
All U.S.
25 38 37
39 20 41
53 20 27
83 13 |4
59 7 34
52 8 40
67 11 22
63 15 22
"Coverage: Estuarine waters of the
contiguous 48 states.
"This indicator is based on a whole-
body analysis of the fish.
Data source: U.S. EPA, 2004 (data
modified to report by EPA Region)
EPA Regions
Exhibit 3-39. Coastal fish tissue contaminant
concentrations in the contiguous U.S., compared with
health-based guidelines, 1997-2000abc
Percent of estuarine sites:
Contaminant
Below Within Exceeding
Guideline range guideline guideline guideline
(ppm) range range range
Arsenic (inorganic)d
Cadmium
Mercury (total body)
Mercury (muscle tissue)
Selenium
Hexachlorobenzene
Lindane
Mirex
Toxaphene
0.35-0.70
PAH (Benzo(a)pyrene)
Total PCBs
0.23-0.47
0.29-0.59
0.0016-0.0032
0.023-0.047
100
99
99
58
100
100
88
99
100
100
100
100
100
100
99
95
70
0
24
0
0
4
0
0
0
0
0
0
0
0
2
11
0
18
0
0
8
<1
0
0
0
0
0
0
<1
3
19
'Coverage: Estuarine waters of the contiguous 48 states.
'Concentrations were measured in whole fish tissue. Mercury data were adjusted to
reflect concentrations in edible fillets, where mercury accumulates (adjustment
factor of 3.0, based on the available literature). All other contaminants are
presented as whole-body concentrations.
'Concentrations are compared with risk guidelines for recreational fishers for four
8-ounce meals per month (U.S. EPA, 2000,2004). Guidelines presented here are
for non-cancer risk, except Total PAHs, which is a cancer risk guideline.
Anorganic arsenic estimated at 2% of total arsenic.
Data source: U.S. EPA, Environmental Monitoring and Assessment Program
(EMAP) National Coastal Database
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1 Indicator Limitations
2 • The indicator does not include data from Louisiana, Florida, Puerto Rico, Alaska, and
3 Hawaii, which had not been assessed at the time this indicator was compiled. Some of these
4 areas (e.g., portions of Alaska) have now been surveyed, and may be included in future
5 indicators.
6 • Whole-body contaminant concentrations in fish overestimate the risk associated with
7 consuming only the fillet portion of the fish, with the exception of mercury and cadmium,
8 which are generally underestimated.
9 • This indicator focuses on contaminants from a human health risk perspective. No EPA
10 guidance criteria exist to assess the ecological risk of whole-body contaminants in fish (U.S.
11 EPA, 2004).
12 • Some fish samples used in the survey were non-market-size juveniles, which are known to
13 have lower contaminant levels than larger, market-sized fish.
14 • Samples are collected during an index period from July to September, and the indicator is
15 only representative of this time period. It is unlikely, however, that contaminant levels vary
16 substantially from season to season.
17 • There are no trend data for this indicator. In NCCRII, fish tissue contaminants are
18 characterized by whole-body concentrations and compared to EPA risk-based consumption
19 guidelines. For EPA's first National Coastal Condition Report (NCCR I), fish contaminants
20 were measured as fillet concentrations and compared to FDA criteria. The data presented here
21 will serve as a baseline for future surveys, however.
22 Data Sources
23 This indicator is based on an analysis published in EPA's National Coastal Condition Report II (U.S.
24 EPA, 2004). Summary data by EPA Region and by contaminant have not been published, but were
25 provided by EPA's National Coastal Assessment program. Underlying sampling data are housed in
26 EPA's National Coastal Assessment database (U.S. EPA, 2005)
27 (http://www.epa.gov/emap/nca/html/data/index.html).
28 References
29 Canadian Council of Ministers of the Environment. 1999. Protocol for the derivation of Canadian tissue
30 residue guidelines for the protection of wildlife that consume aquatic biota. Prepared by the Task Force
31 on Water Quality Guidelines.
32 Kannan, K., R.G. Smith, R.F. Lee, H.L. Windom, P.T. Heimuller, J.M. Macauley, and J.K. Summers.
33 1998. Distribution of total mercury and methyl mercury in water, sediment and fish from South Florida
34 estuaries. Arch. Environ. Con. Tox. 34:109-118.
35 Mikac, N., M. Picer, P. Stegnar, and M. Tusek-Nidari. 1985. Mercury distribution in a polluted marine
36 area, ratio of total mercury, methyl mercury and selenium in sediments, mussels and fish. Water Res.
37 19:1387-1392.
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1 Schmidt, C.J., and W.G. Brumbaugh. 1990. National contaminant biomonitoring program: concentrations
2 of arsenic, cadmium, copper, lead, mercury selenium and zinc in U.S. freshwater fish 1976-1984. Arch.
3 Environ. Con. Toxicol. 19:731-747.
4 U.S. EPA. 2005. EMAP national coastal database. Accessed 2005.
5
6 U.S. EPA. 2004. National coastal condition report II. EPA/620/R-03/002. Washington, DC.
7
8 U.S. EPA. 2000. Guidance for assessing chemical contaminant data for use in fish advisories.
9 EPA/823/B-00/008.
10 Windom, H.L., and D.R. Kendall. 1979. Accumulation and biotransformation of mercury in coastal and
11 marine biota. In: Nriagu, J.O., ed. Biogeochemistry of mercury in the environment. Amsterdam, The
12 Netherlands: Elsevier. pp. 303-323.
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NDICATOR: Contaminants in Lake Fish Tis
2 Lakes and reservoirs provide important sport fisheries and other recreational opportunities, and lake
3 ecosystems provide critical habitat for aquatic species and support wildlife populations that depend on
4 aquatic species for food. Lakes and reservoirs occur in a variety of landscapes and can receive
5 contaminants from several sources, including direct discharges into the water, atmospheric deposition,
6 and agricultural or urban runoff. A group of contaminants of particular concern are the persistent,
7 bioaccumulative, and toxic (PBT) chemicals. These contaminants are highly toxic, long-lasting chemicals
8 that can accumulate in fish, reaching levels that can affect the health of people and wildlife that eat them.
9 PBT contaminants can originate from a variety of sources, many of which are declining. The primary
10 source of one of the most important PBTs, mercury, is atmospheric deposition. Among other important
11 PBTs, most uses of DDT became illegal in the U.S. effective in 1973; production of PCBs in the U.S.
12 ceased in 1977 (although they are still emitted as a byproduct of other manufacturing processes) and most
13 uses phased out in 1979; chlordane was banned in 1988; and quantifiable emissions of dioxin-like
14 compounds from all known sources have decreased in the U.S. by an estimated 89 percent between 1987
15 and 2000 (U.S. EPA, 2006a).
16 This indicator is based on tissue samples of predator and bottom-dwelling fish species collected and
17 analyzed for EPA's National Study of Chemical Residues in Lake Fish Tissue. The data generated from
18 this probabilistic survey (Olsen et al., 1998; U.S. EPA, 1999; Stevens and Olsen, 2003, 2004) are
19 designed to estimate the national distribution of the mean levels of PBT chemicals in fish tissue from
20 lakes and reservoirs of the contiguous 48 states. Fish samples were collected from 500 lakes and
21 reservoirs over a four-year period (2000-2003). Sampling locations were selected from the estimated
22 147,000 target lakes and reservoirs in the contiguous 48 states based on an unequal probability survey
23 design. The lakes and reservoirs were divided into six size categories, and varying probabilities were
24 assigned to each category in order to achieve a similar number of lakes in each size category. The lakes
25 and reservoirs ranged from 1 hectare (about 2.5 acres) to 365,000 hectares (about 900,000 acres), were at
26 least 1 meter (3 feet) deep, and had permanent fish populations.
27 Because no predator or bottom-dwelling species occurs in all 500 lakes and reservoirs, the study focused
28 on 12 target predator species and 6 target bottom-dwelling species in order to minimize the effect of
29 sampling different species. These species were chosen because they are commonly consumed in the study
30 area, have a wide geographic distribution, and potentially accumulate high concentrations of PBT
31 chemicals. Sampling teams applied consistent materials and methods nationwide. From each lake or
32 reservoir, teams collected composite samples of five adult fish of similar size for one predator species
33 (e.g., bass or trout) and one bottom-dwelling species (e.g., carp or catfish) (U.S. EPA, 2000). Fillets were
34 analyzed for predators, and whole bodies were analyzed for bottom-dwelling fish. Fillet data represent the
35 edible part of the fish most relevant to human health, while whole body data are more relevant to wildlife
36 consumption. A single laboratory prepared fish tissue samples for analysis in a strictly controlled
37 environment, and tissue samples were sent to four analytical laboratories. The same laboratory analyzed
38 tissue samples for each chemical group (e.g., PCBs or organochlorine pesticides), using the same standard
39 analytical method, for the duration of the study. The indicator consists of statistical distributions of the
40 concentrations of 15 PBT chemicals or chemical groups in predator and bottom-dwelling fish tissue,
41 including mercury, arsenic (total inorganic), dioxins/furans, total PCBs, and 11 organochlorine pesticides.
42 Fourteen of these chemicals or chemical groups also appear in the Coastal Fish Tissue indicator (p. 3-
43 103).
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1 What the Data Show
2
3
4
5
6
7
9
10
11
12
13
14
Mercury, polychlorinated biphenyls (PCBs), dioxins and furans, and DDT are widely distributed in lakes
and reservoirs in the contiguous 48 states (Exhibits 3-40, 3-41). Mercury and PCBs were detected in 100
percent of both predator and bottom-dweller composite samples. Dioxins and furans were detected in 81
percent of the predator composite samples and 99 percent of the bottom-dweller composite samples, and
DDT was detected in 78 percent of the predator composites and 98 percent of the bottom-dweller
composites. Some of the chemicals analyzed for this study were not detected in any of the fish tissue
samples.
Median concentrations in predator fillets (i.e., half of the lakes and reservoirs had fish with higher values)
were as follows: mercury, 0.285 ppm; total PCBs, 2.161 ppb; dioxins and furans, 0.006 ppt [TEQ]; and
total DDT, 1.47 ppb (Exhibit 3-40). Median concentrations in whole, bottom-dwelling fish were lower for
mercury (0.069 ppm), but higher for total PCBs (13.88 ppb), dioxins and furans (0.406 ppt [TEQ]), and
total DDT (12.68 ppb) (Exhibit 3-41).
Exhibit 3-40. Lake fish tissue PBT contaminant concentration estimates for predators (fillets) in the
contiguous U.S., 2000-2003
Contaminant
Mercury
Total PCBs
TEQ dioxins/furans only
Total inorganic arsenic
Total chlordane
Total DOT
Oicofol
Dieldrin
Number Number
ot of samples
samples above MDL
Percenliles lor lillel tissue concentrations (ppm)'
Total endosulfan
Endrin
Heptachlor epoxide
Hexachlorobenzene
Lindane (gamma BHC)
Mi rex
Toxaphene
486
486
486
486
486
466
486
486
486
486
486
485
486
486
486
486
395
2
96
378
15
24
18
3
6
0
28
10
0
5.h
0.059
0.000351
*
*
*
*
*
*
*
*
10"!
0.089
0.000494
*
*
if
*
*
*
*
*
25th
0.177
0.001000
*
it
*
*
it
*
*
*
50'h
(median)
0.285
0.002161
6x10-'
*
*
0.00147
*
*
*
*
75'h
0.432
0.008129
46 x 10'5
*
*
0.00694
*
*
*
*
90th
0.562
0.018159
109x10^
*
0.003617
0.01966
*
it
*
t
95*
0.833
0.033161
318 x109
*
0.008266
0.03057
*
0.001193
*
*
!MDL - method detection limit; MOLs are available online at http://www.epa.gov/watersciance/fishstudy.
"* = less than MDL
Data source: U.S. EPA. National Study of Chemical Residues in Lake Fish Tissue
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Exhibit 3-41. Lake fish tissue PBT contaminant concentration estimates for bottom-dwellers (whole fish)
in the contiguous U.S., 2000-2003
Contaminant
Mercury
Total PCBs
TEO dioxins/furans only
Total inorganic arsenic
Total chlordane
Total DDT
Dicofol
Dieldrin
Total endosulfan
Endrin
Heptachlor epoxide
Hexachlorobenzene
Lindane (gamma BMC)
Mirex
Number Number
of of samples
samples above MDL
Toxaphene
395
395
395
395
395
395
395
395
395
395
395
395
395
395
395
395
393
36
197
388
8
73
23
14
25
0
31
19
1
Percenliles tor whole body tissue concentrations (ppm)
5«i
0.019
0.001579
19x10'9
*
*
0.00108
*
*
*
*
*
IQlK
0.020
0002308
59x1C'9
*
*
0.00182
*
*
*
*
*
25lh
0.039
0.005146
165x10'
*
*
0.00423
*
*
*
it
*
50tn
(median)
0.069
0013876
406x10'
*
0.001653
0.01268
*
*
*
*
*
75th
0.124
0.070050
1067x10'
*
0.009313
0.03535
*
*
*
*
*
90'n
0.220
0.130787
1770x10"
*
0.025964
0.15392
*
0.003436
*
*
*
95'h
0.247
0.198324
2006 x10'9
0.037
0.030931
0.21863
it
0.024613
it
*
0.000676
0.000729
aMDL - method detection limit; MDLs are available online at http://www.epa.iov/waterscience/tishstudy.
''* = less than MDL
Data source: U.S. EPA. National Study ol Chemical Residues in Lake Fish Tissue
Indicator Limitations
0.001541
0.001866
*
4
5
6
1
8
9
10
11
12
13
14
15
16
• Survey data are not available for Alaska, Hawaii, and Puerto Rico.
• The Great Lakes, the Great Salt Lake, and lakes without permanent fish populations are not
included in the target population.
• Because the distribution of sampling sites was based on the frequency of occurrence of lakes
and reservoirs, contaminants in lakes and reservoirs in arid states (e.g., Arizona, New
Mexico, and Nevada) are not well-represented.
• Due to the inaccessibility (e.g., landowner denial of access) of some target lakes, the results
are representative of the sampled population of lakes (approximately 80,000) rather than the
original target population of 147,000 lakes.
• Trend data are not yet available, as this is the first time that a national lake fish tissue survey
has been conducted using a probabilistic sampling design. These data will serve as a baseline
for future surveys.
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1 Data Sources
2 The data for Exhibits 3-40 and 3-41 were provided by EPA's National Lake Fish Tissue Study. A report
3 on the findings of this study was still in progress at the time this Report on the Environment went to
4 press; however, partial results (number of detections) have been published in U.S. EPA (2006b)
5 (http://www.epa.gov/waterscience/fishstudy/results.htm). along with information about how to obtain
6 more detailed results on CD.
7 References
8 Olsen, A.R., D.L. Stevens, Jr., and D. White. 1998. Application of global grids in environmental
9 sampling. Comp. Sci. Stat. 30:279-284.
10 Stevens, D.L., Jr., and A.R. Olsen. 2004. Spatially-balanced sampling of natural resources. J. Am. Stat.
11 Assoc. 99(465):262-278.
12 Stevens, D.L., Jr., and A.R. Olsen. 2003. Variance estimation for spatially balanced samples of
13 environmental resources. Environmetrics 14:593-610.
14 U.S. EPA. 2006a. Inventory of sources of environmental releases of dioxin-like compounds in the United
15 States: the year 2000 update. EPA/600/P-03/002a. Washington, DC. [link will be provided at future date]
16 U.S. EPA. 2006b. National Lake Fish Tissue Study—results. Updated February 27, 2006.
17
18 U.S. EPA. 2000. Field sampling plan for the national study of chemical residues in lake fish tissue.
19 EPA/823/R-02/004. Washington, DC.
20 U.S. EPA. 1999. National study of chemical residues in lake fish tissue: study design. Washington, DC.
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1 3.8.3 Discussion
2 What These Indicators Say About Trends in the Condition of Consumable
3 Fish and Shellfish and Their Effects on Human Health
4 These indicators provide baseline information about consumable fish in inland lakes, reservoirs, and
5 coastal areas. The data were collected from a variety of species, reflecting many parts of the food web.
6 The results for fish in estuarine sites along the Atlantic, Gulf, and Pacific coasts of the contiguous 48
7 states (Coastal Fish Tissue indicator, p. 3-103) varied substantially among the seven coastal EPA
8 Regions. Fish from the coastal waters of the Southeast (EPA Region 4) generally had "low"
9 contamination scores, while several other Regions had a substantial proportion with "high"
10 contamination. In general, PCBs, mercury, and PAHs appeared to be the contaminants responsible for the
11 most "high" contamination scores.
12 The results for lake fish (Lake Fish Tissue indicator, p. 3-107) suggest that several chemical contaminants
13 are widely distributed in the nation's lakes and reservoirs, including mercury, dioxins and furans, PCBs,
14 and DDT. However, some of the other chemicals in this screening—including certain pesticides and
15 PAHs—were detected rarely or not at all. There were some notable differences between predators and
16 bottom-dwellers, which may be a result of how each type offish was analyzed—fillets for predators and
17 whole fish for bottom dwellers.
18 Limitations, Gaps, and Challenges
19 As explained in Section 3.8.2, both of these indicators have important limitations. For example, like the
20 other coastal indicators from NCCRII (presented in Section 3.5), the Coastal Fish Tissue indicator (p. 3-
21 103) does not display trend data. It is also limited spatially, as adequate data for Alaska, Hawaii, the
22 Caribbean, and the Pacific territories are not available. The lack of data from Alaska is especially notable
23 because more than half of the nation's commercial fish and shellfish catch comes from Alaskan waters.44
24 The Lake Fish Tissue indicator (p. 3-107) is also limited temporally and spatially, with no trend data and
25 no coverage outside the contiguous 48 states. Further, unlike the coastal survey, the lake fish survey was
26 not designed to produce results by region, and it also does not compare contaminant levels to any health-
27 based guidelines. Thus, while both indicators present meaningful data, the results cannot easily be
28 compared.
29 The Lake Fish Tissue and Coastal Fish Tissue indicators (pp. 3-107 and 3-103) do provide some
30 information about contamination and safety offish and shellfish. However, to fully assess the condition of
31 the nation's fish and shellfish, more data are needed—particularly on a national level, because many
32 issues have been studied locally or regionally, but have not yet been studied in nationally representative
33 surveys. In addition to the limitations of the indicators described above, information gaps for answering
34 this question include nationally consistent indicators of pathogens in fish and shellfish, in both fresh water
35 and coastal waters, and of the biological and chemical condition offish and shellfish commercially
36 farmed in the U.S. There are also no ROE indicators to describe the effects offish and shellfish condition
37 on human health. As noted in Chapter 1, it is often difficult to explicitly connect an observed effect to a
44 National Oceanic and Atmospheric Administration. 2005. Fisheries of the United States—2004.
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1 particular stressor (e.g., the condition offish and shellfish that people consume), even though there may
2 be scientific evidence to suggest a possible association.
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CHAPTER 4
LAND
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LAND CHAPTER CONTENTS
4.1 INTRODUCTION 4-5
4.1.1 Overview of the Data 4-6
4.1.2 Organization of This Chapter 4-7
4.2 WHAT ARE THE TRENDS IN LAND COVER AND THEIR EFFECTS ON HUMAN
HEALTH AND THE ENVIRONMENT? 4-9
4.2.1 Introduction 4-9
4.2.2 ROE Indicators 4-9
INDICATOR: Land Cover 4-11
INDICATOR: Land Cover in the Puget Sound/Georgia Basin 4-17
4.2.3 Discussion 4-20
What These Indicators Say About Trends in Land Cover and Their Effects on
Human Health and the Environment 4-20
Limitations, Gaps, and Challenges 4-20
4.3 WHAT ARE THE TRENDS IN LAND USE AND THEIR EFFECTS ON HUMAN
HEALTH AND THE ENVIRONMENT? 4-22
4.3.1 Introduction 4-22
4.3.2 ROE Indicators 4-23
INDICATOR: Land Use 4-24
INDICATOR: Urbanization and Population Change 4-31
4.3.3 Discussion 4-36
What These Indicators Say About Trends in Land Use and Their Effects on Human
Health and the Environment 4-36
Limitations, Gaps, and Challenges 4-36
4.4 WHAT ARE THE TRENDS IN WASTES AND THEIR EFFECTS ON HUMAN
HEALTH AND THE ENVIRONMENT? 4-38
4.4.1 Introduction 4-38
4.4.2 ROE Indicators 4-39
INDICATOR: Quantity of Municipal Solid Waste Generated and Managed 4-40
INDICATOR: Quantity of RCRA Hazardous Waste Generated and Managed 4-43
4.4.3 Discussion 4-46
What These Indicators Say About Trends in Wastes and Their Effects on Human
Health and the Environment 4-46
Limitations, Gaps, and Challenges 4-46
4.5 WHAT ARE THE TRENDS IN CHEMICALS USED ON THE LAND AND THEIR
EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT? 4-48
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4.5.1 Introduction 4-48
4.5.2 ROE Indicators 4-49
INDICATOR: Fertilizer Applied for Agricultural Purposes 4-50
INDICATOR: Toxic Chemicals in Production-Related Wastes Released, Treated,
Recycled, or Recovered for Energy Use 4-54
INDICATOR: Pesticide Residues in Food 4-58
INDICATOR: Reported Pesticide Incidents 4-61
4.5.3 Discussion 4-65
What These Indicators Say about Trends in Chemicals Used on the Land and Their
Effects on Human Health and the Environment 4-65
Limitations, Gaps, and Challenges 4-65
4.6 WHAT ARE THE TRENDS IN CONTAMINATED LAND AND THEIR EFFECTS ON
HUMAN HEALTH AND THE ENVIRONMENT? 4-67
4.6.1 Introduction 4-67
4.6.2 ROE Indicators 4-68
INDICATOR: High-Priority Cleanup Sites with No Human Contact to
Contamination in Excess of Health-Based Standards 4-70
INDICATOR: High-Priority Cleanup Sites Where Contaminated Groundwater Is
Not Continuing to Spread Above Levels of Concern 4-73
4.6.3 Discussion 4-76
What These Indicators Say About Trends in Contaminated Lands and Their Effects
on Human Health and the Environment 4-76
Limitations, Gaps, and Challenges 4-76
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1 4.1 INTRODUCTION
2 The land within the boundaries of the United States, covering nearly 2.3 billion acres, provides food,
3 fiber, and shelter for all Americans, as well as terrestrial habitat for many other species. Land is the
4 source of most extractable resources such as minerals and petroleum; produces renewable resources and
5 commodities such as livestock, vegetables, fruit, grain, and timber; and supports other uses such as
6 residential, industrial, commercial, and transportation. Additionally, land and the ecosystems that it is part
7 of provide services such as trapping chemicals as they move through soil, storing and breaking down
8 chemicals and wastes, and filtering and storing water. The use of land, what is applied to or released on it,
9 and its condition change constantly, including the types and amounts of resources that are extracted,
10 distribution and nature of cover types, amounts and types of chemicals used and wastes managed, and
11 perceptions of the value of land.
12 Numerous agencies and individuals have responsibilities for managing and protecting land in the United
13 States, both in terms of resources associated with land (e.g., timber, minerals) and protection of land (e.g.,
14 wilderness designations, regulatory controls). Between 30 and 40 percent of the nation is owned or
15 managed by public agencies.1 The other 60 to 70 percent is managed by private owners, under a variety of
16 federal, state, and local laws. Local governments have primary responsibilities for regulating land use,
17 while state and federal agencies regulate chemicals and waste which are frequently used and/or stored on
18 or released to land. EPA is interested in land because human activities on land such as food and fiber
19 production, land development, manufacturing, or resource extraction, may involve the creation, use, or
20 release of chemicals and pollutants that can affect the environment and human health.
21 EPA works with other federal agencies, states and partners to protect land resources, ecosystems,
22 environmental processes, and uses of land through regulation of chemicals, waste, and pollutants, and
23 through clean up and restoration of contaminated lands. The complexities of responsibilities underscore
24 the challenges of collecting data and assessing trends on the state of land.
25 In this chapter critical land questions are addressed by describing national trends in naturally occurring
26 and human uses of land, stressors that affect land, and associated exposures and effects among humans
27 and ecological systems. ROE indicators are presented to address five fundamental questions about the
28 state of the nation's land:
29 • What are the trends in extent of land cover and their effects on human health and the
30 environment? Land cover refers to the actual or physical presence of vegetation or other
31 materials (e.g., rock, snow, buildings) on the surface of the land (it varies from land use—see
32 next question below). It is important from the perspective of understanding land as a resource and
33 its ability to support humans and other species. Changes in land cover can affect other media
34 (e .g., air and water).
35 • What are the trends in land use and their effects on human health and the environment?
36 Land use represents the economic and cultural activities practiced by humans on land. Land use
37 can have effects on both human health and the environment, particularly as land is urbanized or
38 used for agricultural purposes.
1 U.S. Census Bureau. 2005. Statistical abstract of the United States. Washington, DC. (2003 data)
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1 • What are the trends in wastes and their effects on human health and the environment?
2 Numerous types of wastes are generated as part of most human activities. Trends in wastes
3 include trends in types and quantities of, and mechanisms for, managing wastes. Waste trends
4 reflect the efficiency of use and re-use of materials and resources and potential for land
5 contamination.
6 • What are the trends in chemicals used on the land and their effects on human health and
7 the environment? Various chemicals are produced or used on land for many purposes. .The
8 quantity and diversity of chemicals and the potential for interactions among them have created
9 challenges in understanding the full effects of their use. Pesticides, fertilizers, and toxic chemicals
10 are examples of chemicals applied or released on land.
11 • What are the trends in contaminated land and their effects on human health and the
12 environment? Contaminated lands are those lands that have been affected by human activities or
13 natural events such as manufacturing, mining, waste disposal, volcanoes, or floods that pose a
14 concern to human health or the environment. The worst contaminated lands are tracked and
15 cleanups are overseen by EPA.
16 These ROE questions are posed without regard to whether indicators are available to answer them. This
17 chapter presents the indicators available to answer these questions, and also points out important gaps
18 where nationally representative data are lacking.
19 4.1.1 Overview of the Data
20 Data are collected by many agencies with varying responsibilities for managing and protecting land and
21 its resources. Several different sources and types of data are used to develop the indicators that address
22 the questions in this chapter. They include:
23 • Satellite imagery. Data used in the land cover question are derived from the analysis of satellite
24 data.2 A national data set of U.S. land cover called the National Land Cover Dataset (NLCD) is
25 currently available for the early to mid-1990s. Analyses of more recent data are currently
26 underway to provide better trend data. Multiple agencies, including EPA, have jointly funded
27 satellite data processing efforts and are working together to derive a common classification
28 approach for the data.
29 • National surveys. The data used in the land use question are primarily derived from two national
30 surveys: the USDA Natural Resources Conservation Service, National Resources Inventory
31 (NRI)3 and the USDA Forest Service, Forest Inventory and Analysis.4 These surveys are collected
32 over specific areas for specific agency purposes. The NRI data are collected only on non-federal
33 lands, and FIA data address only forest and timberlands. These limitations contribute to the need
34 to rely on multiple data sets for national estimates.
2 U.S. Geological Survey. 2005. National land cover dataset, 1992.
3 USDA Natural Resources Conservation Service. 2004. National resources inventory: 2002 annual NRI.
4 USDA Forest Service. 2005. Forest inventory and analysis national program,
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1 • Regulatory data. The data used for most of the chemical, waste, and contaminated land
2 questions are derived from self-reporting or government-collected measurements to address
3 regulatory requirements. For example, the chemical release information reported under the
4 chemical question is derived from the Toxics Release Inventory (TRI) based on industry
5 reporting. These data, in general, represent only a small sample of the total picture of waste,
6 chemicals, and land contamination. State and local governments collect additional data, but the
7 lack of consistency in approaches make compilation of national data difficult.
8 This chapter presents only data that meet the ROE indicator definition and criteria (see Chapter 1,
9 Introduction). Note that non-scientific indicators, such as administrative and economic indicators, are not
10 included in this definition. Thorough documentation of the indicator data sources and metadata can be
11 found online at [insert url]. All indicators were peer-reviewed during an independent peer review process
12 (see insert url for more information). Readers should not infer that the ROE indicators included reflect the
13 complete state of knowledge on the nation's land. Many other data sources, publications, and site-specific
14 research projects have contributed to the current understanding of land trends, but are not used in this
15 report because they did not meet some aspect of the ROE indicator criteria.
16 4.1.2 Organization of This Chapter
17 The remainder of this chapter is organized into five sections corresponding to the five questions that EPA
18 seeks to answer about land. Each section introduces the question and its importance, presents the ROE
19 indicators to help answer the question, and discusses what the ROE indicators, taken together, say about
20 the question. Several of the National Indicators also provide information organized by EPA Regions, and
21 one Regional Indicator addresses specific issues at a sub-EPA region scale. Each section concludes by
22 highlighting the major challenges to answering the question and identifying important gaps and emerging
23 issues.
24 The table below shows the ROE indicators used to answer each question in this chapter and the location
25 where they are presented.
26 Table 4.1.1. Land—ROE Questions and Indicators
27
Question
What are the trends in land cover and
their effects on human health and the
environment?
What are the trends in land use and their
effects on human health and the
environment?
What are the trends in wastes and their
effects on human health and the
environment?
What are the trends in chemicals used on
the land and their effects on human
Indicator Name
Land Cover (N/R)
Forest Extent and Type (N/R)
Land Cover in the Puget Sound/Georgia
Basin (R)
Land Use (N)
Urbanization and Population Change
(N/R)
Quantity of Municipal Solid Waste
Generated and Managed (N)
Quantity of RCRA Hazardous Waste
Generated and Managed (N)
Fertilizer Applied for Agricultural
Purposes (N)
Section Page #
4.2.2 4-11
6.2.2 6-14
4.2.2 4-17
4.3.2 4-24
4.3.2 4-31
4.4.2 4-40
4.4.2 4-43
4.5.2 4-50
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4-7
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Question
Indicator Name
Section Page #
health and the environment?
Toxic Chemicals in Production-Related
Wastes Released, Treated, Recycled, or
Recovered for Energy Use (N)
Pesticide Residues in Food
Reported Pesticide Incidents (N)
4.5.2
4.5.2
4.5.2
4-54
4-58
4-61
What are the trends in contaminated land
and their effects on human health and the
environment?
High-Priority Cleanup Sites with No
Human Contact to Contamination in
Excess of Health-Based Standards (N)
High-Priority Cleanup Sites Where
Contaminated Groundwater Is Not
Continuing to Spread Above Levels of
Concern (N)
4.6.2
4.6.2
4-70
4-73
1
2
3
4
N = National Indicator
R = Regional Indicator
N/R = National Indicator displayed at EPA Regional scale
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1 4.2 WHAT ARE THE TRENDS IN LAND COVER AND THEIR EFFECTS ON
2 HUMAN HEALTH AND THE ENVIRONMENT?
3 4.2.1 Introduction
4 Land cover—the surface components of land that are physically present and visible—provides a means to
5 examine landscape patterns and characteristics. Patterns and landscape characteristics are important in
6 understanding the extent, availability, and condition of lands; ecological system extent, structure, and
7 condition; and the potential for dispersion and effects of chemicals and other pollutants in and on the
8 environment. Land cover represents a starting point from which a variety of monitoring activities can be
9 performed. EPA considers land cover information to be critically important for a number of reasons,
10 including the ability to assess nonpoint sources of pollution, understanding landscape variables for
11 ecological analyses, assessing the behavior of chemicals, and analyzing the effects of air pollution.
12 Land cover, in its naturally occurring condition, integrates and reflects a given site's climate, geology and
13 soils, and available biota over a time span of decades or longer. Land cover can be affected on shorter
14 time scales by naturally occurring disturbances (e.g., storms, floods, fires, volcanic eruptions, insects,
15 landslides) and human activities. Land cover represents the results of both naturally occurring conditions
16 and disturbances and human activities such as population change, industrial and urban development,
17 deforestation or reforestation, water diversion, and road-building. Depending on one's perspective, the
18 changes wrought by natural processes and human activities can be perceived as improvements or
19 degradations of the state of land cover.
20 Land cover is also important because it affects other environmental variables including water quality,
21 watershed hydrology, habitat and species composition, climate, and carbon storage. Land cover influences
22 the mass and energy exchanges between the surface and the atmosphere and thus influences weather and
23 climate.5 Land cover is also a primary ingredient of ecological structure and function, with changes
24 affecting species habitat and distribution. Land cover changes in watersheds can alter hydrologic regimes,
25 runoff patterns, and flood buffering.6
26 4.2.2 ROE Indicators
27 The question of trends in and effects of land cover is addressed by two National Indicators and one
28 Regional Indicator (see Table 4.2.1). Nationwide land cover information is derived from two data
29 collection programs: the National Land Cover Dataset (NLCD) and the Forest Inventory and Analysis
30 (FIA). The NLCD is described in more detail in the Land Cover indicator summary (p. 4-11), and the FIA
31 is described in the Forest Extent and Type indicator summary (p. 6-14).
32 The classification approach used in the Land Cover indicator is primarily based on the use of satellite data
33 processing. Where satellite data were not available or processed, survey data have been included to
5 Marland, G., et al. 2003. The climatic impacts of land surface change and carbon management, and the
implications for climate-change policy, dim. Pol. 3:149-157.
6 de Sherbinin, A. 2002. Land-use and land-cover change: a CIESIN thematic guide. Palisades, NY: Center for
International Earth Science Information Network of Columbia University.
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1 develop the national statistics.7 The classification approach used in the Land Cover in Puget
2 Sound/Georgia Basin indicator (p. 4-17), while also based on satellite data, is different from the Land
3 Cover National Indicator, and is described in the Regional Indicator discussion. More detailed definitions
4 of land cover types are included in the glossary.
5 Data for the Land Cover in Puget Sound/Georgia Basin indicator are derived from the NOAA Coastal
6 Change Analysis Program (C-CAP) and Landsat satellite data of both the U.S. and Canadian portions of
7 the Puget Sound Basin. This indicator depicts two cover classes: forest and urban.
8 The data presented in the Forest Extent and Type indicator are derived from national surveys of forest
9 land and timberland in the U.S. These data reflect total extent of forest land both nationally and by EPA
10 Region, as well as trends in many species types on timber land.
11 Table 4.2.1. ROE Indicators of Trends in Land Cover and Their Effects on Human Health and the
12 Environment
NATIONAL INDICATORS
Land Cover (N/R)
Forest Extent and Type (N/R)
REGIONAL INDICATORS
Land Cover in the Puget Sound/Georgia Basin
LOCATION
4.2.4 -p. 4-11
6.2.2 -p. 6-14
4.2.2 -p. 4-17
13 N/R = National Indicator displayed at EPA Regional scale
14
7 Categories included in the land cover map (Exhibit 4-1) are derived from satellite data and include: Agricultural
lands, which consist of herbaceous vegetation that has been planted or is intensively managed for the production of
food, feed, or fiber. Developed lands have at least 30 percent constructed materials (e.g., asphalt, concrete,
buildings). Forest consists of naturally occurring or semi-naturally occurring woody vegetation, generally 25-100
percent cover and greater than 6 meters tall. Grassland is dominated by upland grasses and forbs that are not subject
to intensive management, but may be used for grazing. Shrubland is characterized by naturally or semi-naturally
occurring woody vegetation with aerial stems and less than 6 meters tall. "Other" includes ice/snow, bare rock,
quarries/mines, and "transitional" areas. Based on the use of FIA data in Exhibits 4-2 and 4-3, for Alaska and
Hawaii, the forest category includes land defined as: "Land at least 10 percent stocked by forest trees of any size."
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INDICATOR: Land Cover
2 Land cover represents the actual or physical presence of vegetation (or other materials where vegetation is
3 non-existent) on the land surface. Land cover is also often described as what can be seen on land when
4 viewed from above. Land cover represents one means to categorize landscape patterns and characteristics,
5 and is critical in understanding the condition of the environment, including the availability of and changes
6 in habitat, and dispersion and effects of chemicals and other pollutants in and on the environment. For the
7 purposes of this indicator, land cover is described in terms of six major classes: forest, grass, shrub,
8 developed, agriculture, and other (includes ice/snow; bare rock; quarries/mines; wetlands; and
9 "transitional" areas of sparse vegetative cover with less than 25 percent of cover that are dynamically
10 changing from one land cover to another, often because of land use activities such as timber harvesting or
11 fire). "Water" represents a seventh category, but is not discussed as a "land" cover type in this chapter.
12 See the Water Chapter for more details. More information about forest land can be found in the Forest
13 Extent and Type indicator (p. 6-14), and wetland acreage is discussed in greater detail in the Wetlands
14 indicator (p. 3-53).
15 In 1992, several federal agencies agreed to operate as a consortium - known as the Multi-Resolution Land
16 Characteristics (MRLC) Consortium, to acquire and analyze satellite-based remotely sensed data for
17 environmental monitoring programs (MRLC Consortium, 2006). The initial result of the MRLC was
18 development of the 1992 National Land Cover Dataset (NLCD), which is the only comprehensive recent
19 classification of land cover in the continental United States. In many locations, the best available Landsat
20 images were collected between 1991 and 1993, with data in a few locations ranging from 1986 to 1995.
21 This indicator represents data from the 1992 NLCD and the U.S. Forest Service Forest Inventory and
22 Analysis (FIA), which uses a statistical survey design and comparable methods to assess the extent, type,
23 age, and health of forests on private and public land in all states. The 1992 NLCD provides a synoptic
24 classification of land cover, but does not include Alaska and Hawaii, thereby classifying only 1.92 billion
25 acres out of approximately 2.3 billion acres of land in the United States. To supplement NLCD, data from
26 the 1992 FIA were used to provide forest cover estimates in those two states (130.9 million acres). For
27 this indicator, the 21 land cover classes created in the NLCD were aggregated into the six major land
28 cover types described above, along with water (Heinz Center, 2005).
29 What the Data Show
30 The combination of the NLCD for the contiguous 48 states and FIA for forest cover estimates in Alaska
31 and Hawaii shows approximately 694 million acres of forest, 510 million acres of agriculture, 350 million
32 acres of shrub, 307 million acres of grass, and 41 million acres of developed covertypes (Exhibits 4-1 and
33 4-2).
34 NLCD and FIA data show variation in cover types by EPA Region, with forest dominating in Regions 1,
35 2, 3, 4, and 10; agriculture in Regions 5 and 7; grass in Region 8; and shrub in Region 9 (Exhibit 4-3).
36 Region 6 consists of nearly equal coverage of grass, shrub, agriculture, and forest cover. More than two-
37 thirds of the grass acreage in the nation is located in Regions 6 and 8, nearly two-thirds of shrub acreage
38 is in Regions 6 and 9, and nearly half the forest acreage in Regions 4 and 10 (including Alaska).
39
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Exhibit 4-1. Land cover of the contiguous U.S., based on 1992 NLCD'
• ,
Agriculture J Shrub cover
I Developed • Water
I Forest cover Other1'
Grass cover
'See text box on page *
-------
Exhibit 4-2. Land cover types in the U.S., based
on 1992 NLCD and FIAab
Exhibit 4-3. Land cover types in the U.S. by
EPA Region, based on 1992 NLCD and FIAab
Forest cover
694.0 million acres
(33.8%)
Other" /
120.6 million
acres
(5.9%) Water
33.2 million
acres
(1.6%)
Shrub cover
349.9 million
acres
(17.0%)
Developed
41.2 million
acres
(2.0%)
Agriculture
509.8 million acres
(24.8%)
Grass cover
306.6 million
acres
(14.9%)
Coverage: All surface area of the contiguous 48 states, plus forest
land in Alaska and Hawaii.
bSee text box on page x-xx for definitions of land cover categories.
""Other" includes ice/snow, rock, quarries/mining, wetlands, and
transitional areas.
Data source: Data for the contiguous 48 states from the 1992
National Land Cover Dataset (NLCD). Data for Alaska and Hawaii
forest land from the USDA Forest Service, 1992 Forest Inventory
and Analysis (FIA).
tuu
350
_ 300
£
S 250
=
§ 200
"E
•r 150
CO
-------
Definitions of Land Cover Categories for Exhibits 4-1, 4-2, and 4-3
agricultural (NLCD definition): Areas characterized by herbaceous vegetation that has been planted; is
intensively managed for the production of food, feed, or fiber; or is maintained in developed settings for specific
purposes. Herbaceous vegetation must account for 75 to 100 percent of the cover. Includes the
orchards/vineyards/other subcategory, which covers areas planted or maintained for the production of fruits, nuts,
berries, or ornamentals. Excludes urban/recreational grasses, which fall under the "developed" category.
developed (NLCD definition): Areas characterized by a high percentage (30 percent or greater) of constructed
materials (e.g., asphalt, concrete, buildings). Includes the urban/recreational grasses subcategory, which covers
vegetation (primarily grasses) planted in developed settings for recreation, erosion control, or aesthetic purposes.
Examples include parks, lawns, golf courses, airport grasses, and industrial site grasses.
shrubland (NLCD definition): Areas characterized by natural or semi-natural woody vegetation with aerial
stems, generally less than 6 meters tall. Both evergreen and deciduous species of true shrubs, young trees, and
trees or shrubs that are small or stunted because of environmental conditions are included.
grassland (NLCD definition): Areas dominated by upland grasses and forbs. In rare cases, herbaceous cover is
less than 25 percent but exceeds the combined cover of the woody species present. These areas are not subject to
intensive management, but they are often used for grazing.
forest: (NLCD definition) Areas characterized by tree cover (natural or semi-natural woody vegetation,
generally greater than 6 meters tall); tree canopy accounts for 25 to 100 percent of the cover.
(FIA definition) Land at least 10 percent stocked by forest trees of any size, including land that formerly
had such tree cover and that will be naturally or artificially regenerated. Forest land includes transition
zones, such as areas between heavily forested and nonforested lands that are at least 10 percent stocked
with forest trees and forest areas adjacent to urban and built-up lands. Also included are pinyon-juniper
and chaparral areas in the West and afforested areas. A forested area must be at least 1 acre in size to be
classified as forest land. Roadside, streamside, and shelterbelt strips of trees must have a crown width of
at least 120 feet to qualify as forest land. Unimproved roads and trails, streams, and clearings in forest
areas are classified as forest if less than 120 feet wide. (FIA data are used in Alaska and Hawaii, due to
lack of NLCD availability.)
Source: USGS, 2005b; Powell et al., 1994.[0]
Indicator Limitations
5 • Trend data are not available for this indicator. Land cover data for the entire nation at
6 adequate resolution to support this indicator are currently only available as a one-time
7 snapshot, and are nearly fifteen years old (NLCD data represent an approximately 1992
8 vintage dataset). The MRLC Consortium is developing a vintage 2001 database, but until this
9 project is completed, there are no consistent, comprehensive, nationwide data to describe
10 trends in land cover at the national or EPA Regional levels. The 1992 NLCD will serve as a
11 baseline for future inventories.
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1 • FIA data for forest land in Alaska and Hawaii were used to complement the NLCD because
2 NLCD data do not exist for these states. . On-going data collection under both FIA and
3 NLCD are needed to assess land cover trends.
4 • National estimates of land cover vary, depending on the survey, data sources, classification,
5 timing, etc., resulting in varying estimates of the extent of a given land cover category
6 depending on the data set used. Techniques relying on satellite data to generate land cover
7 estimates classify what is visible from above, meaning they may underestimate developed
8 cover in heavily treed urban areas and underestimate forest cover where trees have been
9 harvested. For example, FIA estimates of forestland in 1992 are nearly 8 percent above
10 NLCD, National Resources Inventory (NRI) estimates for developed land are 110 percent
11 above NLCD, and NRI estimates for agriculture land are less than 1 percent below NLCD
12 (USDA Natural Resources Conservation Service, 2004). There are more variations in acreage
13 based on data set comparisons at the regional level, with FIA estimating almost 42 percent (9
14 million acres) more forestland in EPA Region 9 than NLCD, NRI estimating more than 213
15 percent (3.7 million acres) more developed land in Region 8 than NLCD and 158 percent (8
16 million acres) more in Region 6. NRI also estimates 8 percent (10 million acres) less
17 agricultural land in Region 5 than NLCD.
18 • No standardized land cover classification system is currently used among federal agencies.
19 As a result of this limitation, there is no consistency in the assessment of land cover trends
20 across agencies.
21 Data Sources
22 Land cover data for the contiguous 48 states were obtained from the National Land Cover Dataset
23 (NLCD) (USGS, 2005a) (http://landcover.usgs.gov/natllandcover.php). These data were grouped into the
24 major land cover categories as described by the Heinz Center (2005) [see technical note for the Heinz
25 Center's "Ecosystem Extent" indicator]. Forest cover estimates for 1992 in Alaska and Hawaii were
26 obtained from a report published by the USDA Forest Service's Forest Inventory and Analysis (FIA)
27 program (Powell et al., 1994).
28 References
29 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. The state of the
30 nation's ecosystems: measuring the lands, waters, and living resources of the United States. New York,
31 NY: Cambridge University Press, September 2002. Web update 2005:
32
33 MRLC Consortium. 2006. About the MRLC program. Accessed January 2006.
34
35 Powell, D.S., J.L. Faulkner, D.R Darr, Z. Zhu, D.W. MacCleery. 1994. Forest resources of the United
36 States, 1992. General Technical Report RM-234. Fort Collins, CO: USDA Forest Service, Rocky
37 Mountain Forest and Range Experiment Station.
38 (report),
39 (data),
40 (glossary)
41 USDA Natural Resources Conservation Service. 2004. National Resources Inventory: 2002 annual NRI.
42
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1 USGS. 2005a. National Land Cover Dataset 1992 (NLCD 1992). Accessed 2005.
2
3 USGS. 2005b. NLCD land cover class definitions,
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INDICATOR: Land Cover in the Puget Sound/Georgia Basin
2 Changes in land use and corresponding changes in land cover can alter the basic functioning and
3 resilience of ecological systems. Watersheds are one type of system that experiences a cascade of effects
4 among its critical physical, chemical, and biological processes when land cover changes (NWP, 1995;
5 Thorn and Borde, 1998). For instance, removal of vegetation can increase erosion, leading to impacts on
6 soil and water quality; and increases in developed land typically result in a corresponding increase in
7 impervious surfaces with consequences for runoff among other issues. While individual impacts to a
8 landscape may appear as small changes, the combined impacts of particular land uses or land
9 management practices on watersheds can have substantial effects on water quality, species composition,
10 and flooding patterns (PSAT, 2002, 2004). Such combined impacts are often referred to as 'cumulative
11 effects.' As a result of their potential to broadly and substantially influence environmental condition, land
12 cover and use are important factors to monitor.
13 This indicator compares changes in two land-cover metrics for the Puget Sound and Georgia Basin in
14 Washington state and part of British Columbia, Canada. The metrics include percent change of urban and
15 forest land cover. Data cover the period from 1995 to 2000 for the U.S. portion of the basin and from
16 1992 to 1999 for the Canadian side of the basin. The metrics represent the change in total urban or
17 forested land area divided by total land area in the watershed. Forest and urban land cover are two of the
18 most important factors affecting the condition of watersheds in the Puget Sound Basin (Alberti and
19 Marzluff, 2004; Alberti, 2005). In contrast to the nationwide land cover indicator, which is based on
20 NLCD data, the underlying data for this indicator are derived from four assembled USGS Landsat scenes
21 covering the US portion of the Puget Sound Basin and from a combined scene covering the Canadian land
22 area. The land cover data for all USGS 6th field watersheds in the basin was produced from NOAA
23 Coastal Change Analysis Program (C-CAP) data and from Canadian Baseline Thematic Mapping (BTM)
24 data. The USGS Hydrologic Units (HUCs) and Canadian watershed groupings provide topographically
25 delineated watersheds which are aggregated, or 'nested', into larger sub-basin and basin units.
26 What the Data Show
27 Forest Cover
28 Of the 2,725 watersheds assessed, little or no change in forest cover was observed in 2,068 watersheds
29 (76 percent) (Exhibit 4-4, panel A). However, 279 watersheds (10 percent) saw at least 2.5 percent of
30 their mature forest cover converted to some other land cover, often bare ground, immature vegetation, or
31 industrial/urban uses. At the same time, another group of 205 watersheds (8 percent), generally those at
32 higher elevations, indicated a net increase in forest cover as young stands or cleared areas have re-grown
33 into more mature forest cover classes.
34 Urbanization
35 During the same period, little or no change in urban land cover was observed in approximately 90 percent
36 of the 2,725 assessed watersheds within the basin (Exhibit 4-4, panel B). However, urbanization increased
37 across many low elevation watersheds and shoreline areas, with 158 watersheds (6 percent) expanding the
38 urban portion of the watershed by between 0.7 and 1.93 percent, and another 58 watersheds (2 percent)
39 showing increases of more than 1.93 percent. Research has shown that once roughly 10 percent of a
40 watershed's drainage area becomes paved or otherwise impervious, there is a high potential for physical,
41 chemical, and biological impairments to both water quality conditions and other aquatic resources (NWP,
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1 1995; Albert! and Marzluff, 2004). Recent assessments find that numerous Puget Sound watersheds are
2 nearing or exceeding this level of development (Alberti et al., 2004).
3
4
Exhibit 4-4. Land cover change in watersheds of the
Puget Sound/Georgia Basin, 1992-2000'b
A. Forest cover
British
Columbia
Washington
Percent change in (oresl cover:
• -5.0% or more i! No change
-4.9% to -2.5% 0.1 % to 0.85%
-2.4% to -0.1% • More than 0.85%
£,JUU
« 2.000
JG
CO
i
| 1,000
3 500
0
2,068
147 132 173
.• a
96 109
mm.
B. Urbanization
British
Columbia^*
Washington
Percent change in urbanization:
a No change • 0.301 % to 0.70%
0.05% or less • 0.71% to 1.93%
0.051% to 0.30% • More than 1.93%
2,500
S 2,000
S
I 1'500
21,000
E
I 500
0
2.329
132 30 18 58
Percent change
Percent change
'Coverage: 2.725 watersheds within the Puget Sound/Georgia Basin, located in the
state of Washington and the Canadian province of British Columbia. U.S. watersheds
are 12-digit Hydrologic Unit Code (HUC12) watersheds.
"U.S. data reflect changes from 1995 to 2000, while Canadian data reflect changes from
1992 to 1999.
Data source: U.S. data from NOAA, Coastal Change Analysis Program (C-CAP).
Canadian data from Canadian Baseline Thematic Mapping (BTM). Cartography by
CommEnSpace.
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1 Indicator Limitations
2 • While the U.S. C-CAP data and the Canadian BTM data have similar and overlapping time
3 periods, as currently presented, the U.S. data reflect change from 1995 to 2000 and the
4 Canadian data reflect change from 1992 to 1999.
5 • The size of the data pixels and the minimum mapping unit size affects the classification of
6 certain features such as narrow riparian corridors, and can affect the percentages in the
7 indicators.
8 Data Sources
9 The full analysis has not been published, but it is based on publicly available datasets compiled by
10 CommEnSpace (http: //www. commenspace. org). Raw data for the U.S. portion of this indicator are
11 available from NCAA's Coastal Change Analysis Program (C-CAP) (NOAA, 2006)
12 (http://www.csc.noaa.gov/crs/lca/locate.html). and Canadian data are available from the British Columbia
13 Integrated Land Management Bureau (2001)
14 (http://ilmbwww.gov.bc.ca/cis/initiatives/ias/btm/index.html).
15 References
16 Alberti, M. 2005. The effects of urban patterns on ecosystem function. Int. Regional Sci. Rev. 28(2): 168-
17 192.
18 Alberti, M., and J. Marzluff 2004. Resilience in urban ecosystems: linking urban patterns to human and
19 ecological functions. Urb. Ecosyst. 7:241-265.
20 British Columbia Integrated Land Management Bureau. 2001. Baseline thematic mapping.
21
22 NOAA. 2006. Coastal Change Analysis Program (C-CAP) database. Accessed 2006.
23
24 NWP (Northwest Forest Plan). 1995. Ecosystem analysis at the watershed scale: federal guide for
25 watershed analysis. Portland, OR: USFS Regional Ecosystem Office.
26 PSAT (Puget Sound Action Team). 2002. Puget Sound update. Eighth report of the Puget Sound ambient
27 monitoring program. Olympia, WA
28 PSAT (Puget Sound Action Team). 2004. State of the Sound. Report to the Washington state legislature.
29 Olympia, WA
30 Thorn, R., and A. Borde. 1998. Human intervention in Pacific Northwest coastal ecosystems. In:
31 McMurray, G.R., and R.J. Bailey, eds. Change in Pacific Northwest coastal ecosystems. NOAA coastal
32 ocean program decision analysis series no. 11.
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1 4.2.3 Discussion
2 What These Indicators Say About Trends in Land Cover and Their Effects
3 on Human Health and the Environment
4 The data presented for the Land Cover indicator (p. 4-11) are only available for one point in time, 1992,
5 and thus do not provide trend information. The data do, however, represent a baseline for future land
6 cover trend assessments. The data show that the largest extent of a cover type nationwide is forest land,
7 followed by agriculture, shrubland, grassland, and developed land.
8 The Land Cover in Puget Sound/Georgia Basin indicator (p. 4-17) shows that land cover in the majority
9 of the approximately 2,700 sub-watersheds comprising the Puget Sound and Georgia Basin did not
10 change appreciably during the time periods covered by the indicator. The data in this Regional Indicator
11 allow for discrimination of patterns of watersheds where land cover has changed even in the relatively
12 short interval of five years. For example, forest cover tended to decrease in coastal and mid-elevation
13 watersheds, while showing a net increase at higher elevations. Developed land cover increased somewhat
14 in approximately 8 percent of the sub-watersheds, mainly in watersheds at low elevations and along the
15 shore. These and related trends may have consequences for human health and ecologic conditions in the
16 areas where land cover is changing. For example, increases in developed land cover may be associated
17 with increases in impervious surface area, which can cause changes in surface water runoff quantity and
18 quality to the point where detrimental effects on aquatic resources may occur.8
19 The Forest Extent and Type indicator (p. 6-14) provides trend data for forest land cover, and shows that
20 the total amount of forest land in the U.S. has remained relatively constant over recent years. On a
21 regional basis, however, there have been shifts, including increases in forest cover in EPA Regions 2, 3,
22 and 5, and decreases in Regions 6 and 9. The species composition of forest cover has also shifted.9
23 Limitations, Gaps, and Challenges
24 The lack of trend data is a key limitation of the Land Cover indicator (p. 4-11) as well as a gap in the data.
25 The changing availability of technology since the 1970s, such as satellites and computing capacity to
26 process large volumes of data, has provided new tools in the effort to track trends in land cover. The use
27 of these tools continues to be constrained due to complexities in land cover and costs of processing. This
28 is one reason that trend data for national land cover using satellite data are not currently available.
29 Another gap is the lack of indicators for human health effects related to trends in land cover. While land
30 cover extent may represent a measure of ambient conditions and is a critical input to many other analyses
31 (e.g., models of the water cycle, carbon cycle, ecological system function), it provides limited insight in
32 answering the question of effects on human health.
8 U.S. EPA. 2005. Estimating and projecting impervious cover in the southeastern United States. EPA/600/R-
05/061. Athens, GA.
9 These changes and their effects on the environment are described in Chapter 6.
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1 There are several challenges related to addressing the question of trends in land cover. Two critical ones
2 are, first, that land cover characteristics can vary, depending on the scale of mapping or measurement and,
3 second, the classification systems that are used to describe land cover vary by agency and their needs. The
4 variability of species and structure within land cover types can be important in how land cover is affected
5 by pollutants or the type of habitat that is provided. While mapping or measuring the details of species
6 and structure of forest or shrubland is possible on a local basis, it is very difficult to do consistently
7 nationally. There are many different types or categories of land cover that can be defined at very different
8 levels of detail, and different classification schema often make comparability among data sets and across
9 time frames difficult. The major sources of data used to track land cover are based on national surveys
10 using unique classifications that have been maintained over time to allow valid comparisons of important
11 characteristics to be made. At the same time, technology is changing what can be measured, mapped, and
12 classified. Data that can be collected from ground surveys or in some cases inferred from aerial photo
13 interpretation such as understory species are seen differently in automated satellite data processing.
14 Coordinating, integrating, and using data collected at a variety of scales and based on diverse data sources
15 and classifications are challenges in tracking trends in and effects of land cover.
16
17
18
19
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1 4.3 WHAT ARE THE TRENDS IN LAND USE AND THEIR EFFECTS ON HUMAN
2 HEALTH AND THE ENVIRONMENT?
3 4.3.1 Introduction
4 Land use represents the economic and cultural activities that are practiced at a place, such as agricultural,
5 residential, industrial, mining, and recreational uses. Land use changes occur constantly and at many
6 scales, and can have specific and cumulative effects on air and water quality, watershed function,
7 generation of waste, extent and quality of wildlife habitat, climate, and human health. Land use differs
8 from land cover in that some uses may not always be physically obvious (e.g., land used for producing
9 timber but not harvested for many years or land used for grazing but without animals will not be visible).
10 Public and private lands frequently represent very different uses. Urban development seldom occurs on
11 public lands, while private lands are infrequently protected for wilderness uses. .
12 EPA is concerned about the use of land because of the potential effects of land use and its by-products on
13 the environment. For example, land development creates impervious surfaces through construction of
14 roads, parking lots, and other structures. Impervious surfaces contribute to non-point source water
15 pollution by limiting the capacity of soils to filter runoff. Impervious surface areas also affect peak flow
16 and water volume, which heighten erosion potential and affect habitat and water quality. Increased storm
17 water runoff from impervious surfaces can deliver more pollutants to water bodies that residents may rely
18 on for drinking and recreation.10 Storm runoff from urban and suburban areas contains dirt, oils from road
19 surfaces, nutrients from fertilizers, and various toxic compounds. Point source discharges from industrial
20 and municipal wastewater treatment facilities can contribute toxic compounds and heated water.
21 Impervious surfaces also affect groundwater aquifer recharge.
22 Some land development patterns, in particular dispersed growth such as "suburbanization," can contribute
23 to a variety of environmental concerns such as increased air pollution due to increased vehicle use. This
24 can result in increased concentrations of certain air pollutants in developed areas that may exacerbate
25 human health problems such as asthma.11 Another potential effect of land development is the formation of
26 "heat islands," or domes of warmer air over urban and suburban areas, caused by the loss of trees and
27 shrubs and the absorption of more heat by pavement, buildings, and other sources. Heat islands can affect
28 local, regional, and global climate, as well as air quality.12
29 Agricultural land uses can affect the quality of water and watersheds. The types of crops planted, tillage
30 practices, and various irrigation practices can limit the amount of water available for other uses. Livestock
31 grazing in riparian zones can change landscape conditions by reducing stream bank vegetation and
32 increasing water temperatures, sedimentation, and nutrient levels. Runoff from pesticides, fertilizers, and
33 nutrients from animal manure can also degrade water quality. Additionally, agricultural land uses may
10 U.S. EPA. 2005. Estimating and projecting impervious cover in the southeastern United States. EPA/600/R-
05/061. Athens, GA.
11 Schwartz! 2004. Air Pollution and Children's Health. Pediatrics 113:1037-1043
12 U.S. EPA. 2003. Cooling summertime temperatures: strategies to reduce urban heat islands. EPA/430/F-03/014.
Washington, DC.
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1 result in loss of native habitats or increased wind erosion and dust, exposing humans to particulate matter
2 and various chemicals.13
3 Some land uses can accelerate or exacerbate the spread of invasive species. Certain land use practices.
4 such as overgrazing, land conversion, fertilization, and the use of agricultural chemicals can enhance the
5 growth of invasive plants.14 These plants can alter fish and wildlife habitat, contribute to decreases in
6 biodiversity, and create health risks to livestock and humans. Introduction of invasive species on
7 agricultural lands can reduce water quality and water availability for native fish and wildlife species.
8 Research is beginning to elucidate the connections between land use changes and infectious disease. For
9 example, fragmentation of forest habitat into smaller patches separated by agricultural activities or
10 developed land increases the "edge effect" and promotes the interaction among pathogens, vectors, and
11 hosts.15
12 In some cases, changes in land use may have positive effects, such as increasing habitat as a result of
13 deliberate habitat restoration measures; and reclamation of lands for urban/suburban development as a
14 result of cleanup of previously contaminated land.
15 4.3.2 ROE Indicators
16 The question of trends in land use is addressed by two ROE indicators: Land Use and Urbanization and
17 Population Change (Table 4.3.1). The primary information sources forthese indicators are the National
18 Resources Inventory (NRI) prepared by the U.S. Department of Agriculture's Natural Resources
19 Conservation Service (NRCS); the Forest Service's Forest Inventory and Analysis (FIA) Program; the
20 National Agricultural Statistical Service (NASS) Census of Agriculture; and population data collected by
21 the U.S. Census Bureau. The glossary includes definitions of the categories used in the indicators.
22 Table 4.3.1. ROE Indicators of Trends in Land Use and Their Effects on Human Health and the
23 Environment
NATIONAL INDICATORS
Land Use (N/R)
Urbanization and Population Change (N/R)
LOCATION
4.3.2 -p. 4-24
4.3.2 -p. 4-31
24 N/R = National Indicator displayed at EPA Regional scale
13 Schenker, M. 2000. Exposures and health effects from inorganic agricultural dusts. Environ. Health Persp.
108(Suppl 4):661-664.
14 U.S. Fish and Wildlife Service. 2002. Invasive species encroachment is one of the biggest threats to native
ecosystems that resource managers face today,
15 Patz, J.A., et al. 2004. Unhealthy landscapes: policy recommendations on land use change and infectious disease
emergence. Environ. Health Persp. 112:1092-1098.
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INDICATOR: Land Use
2 Land use is the purpose of human activity on the land. Unlike land cover, land use may not always be
3 visible. For example, a unit of land designated for use as timberland may appear identical to an adjacent
4 unit of protected forestland, or if recently harvested, it may appear not to be in forest land cover at all.
5 Land use is generally designated through zoning or regulation and is one of the most obvious effects of
6 human inhabitation of the planet. It can affect both human health and ecological systems, as for example,
7 changing the hydrologic characteristics of a watershed, the potential of land to erode, the condition or
8 contiguity of plant and animal habitat, or the spread of vector-borne diseases.
9 This indicator tracks trends in acreages of major land uses over the period 1977-2002 using several data
10 sources. These sources do not always cover the same time period, sample the same resource or
11 geography, or use the same definitions, but each of the sources provides an important piece of the land
12 use picture over time. Definitions for the various land use categories in this indicator can be found at on
13 the following pages.
14 The National Resources Inventory (NRI) conducted by the USDA Natural Resources Conservation
15 Service was used to track trends in "crop and pasture" land (row crop, orchard, and pasture uses) and
16 "developed" land (residential, commercial, industrial, and transportation uses). The NRI developed
17 estimates every five years on non-federal lands in the contiguous U.S. between 1977 and 1997, and
18 annual estimates based on a smaller sample size beginning in 2001.
19 The Forest Inventory and Analysis (FIA) surveys conducted by the USDA Forest Service were used to
20 track trends in forest and timberlands. The FIA surveys include both private and public land in all 50
21 states. The FIA previously assessed forest and timberland acreage every ten years, but the data are now
22 updated on a rolling basis using surveys that sample a different portion of FIA sites every year.
23 The USDA National Agricultural Statistical Service (NASS) Census of Agriculture was used to track
24 trends in the extent of "crop and pasture" land and "farm rangeland" (typically improved pasture). NASS
25 data are available for 1997 and 2002 only. Data on the extent of grass and forested rangeland (typically
26 "unimproved" grazing land) are available from the USDA Economic Research Service (ERS) for one year
27 only, 1997.
28 What the Data Show
29 The acreage of lands used for growing food and forage crops has declined since 1982, while developed
30 land has increased, and timberland has remained approximately constant (Exhibit 4-5). As of 2002,
31 estimates from both NRI and NASS indicate that about 370 million acres were used for food crop
32 production, approximately 16 percent of the U.S. land area. Estimates of pasture or land used to support
33 forage for livestock vary, depending on the definitions. The NRI classified 117 million acres as pasture,
34 while the NASS classified about 60 million acres as cropland used for pasture. NASS classifies nearly
35 400 million additional acres as pasture or rangeland for grazing. The broader ERS estimate of land
36 available for grazing totals about 580 million acres, and includes rangeland, grassland, shrubland, and
37 cropland pasture. If forest lands used for grazing are also included, the total ERS estimate for these lands
38 was 720 million acres in 1997. The NASS shows a slight decrease in the extent of cropland (5 million
39 acres), pasture (6 million acres), and rangeland (3 million acres) between 1997 and 2002. The NRI data
40 suggest that these declines are part of a longer trend, with NRI cropland and pasture declining by slightly
41 more than 64 million acres (12 percent) between 1982 and 2002.
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Exhibit 4-5. Land use trends in the U.S., 1977-2002"
800
700
600
500
400
300
200
100
NRI
D Pas
D Cro
ture
pland
131.0
419.6
125.1
381.2
117.3
368.4
NASS
D Cropland pasture
D Cropland
664
378.9
373.6
NASS
D Pastureland and rangeland
398.2
395.3
1977 1982 1987 1992 1997 2002 1977 1982 1987 1992 1997 2002 1977 1982 1987 1992 1997 2002
800
700
600
500
400
300
200
100
ERS
D Forest-use land
D Grassland pasture
and range
FIA
D Timbertand
140.7
580.2
492.4
484.9
503.7
503.5
NRI
D Developed
[7O1I 79.5 || 86.5 || 98.3 ||107.3|
" 1977 1982 1987 1992 1997 2002 1977 1982 1987 1992 1997 2002 1977 1982 1987 1992 1997 2002
Year
"See text box on page x-xx for definitions of land use categories.
Data source: ERS data from Vesterby and Krupa, 2001. FIA data from the USDA Forest Service, Forest Inventory and Analysis (FIA) Program and
from Smith et al., 2004. NASS data from USDA, 2004. NRI data from the USDA Natural Resources Conservation Service and from USDA, 2000.
1 According to the NRI, nearly 5 percent (or 107.3 million acres) of U.S. land area was considered
2 developed16 as of 2002 (Exhibit 4-5). This represents a gain of 47 percent (34.5 million acres) since 1982.
3 While the amount of developed land is a small fraction of the total, its ecological impact can be
4 disproportionately high relative to other land use types. Paving and the creation of other impervious
5 surfaces can change local hydrology, climate, and carbon cycling, leading to increased surface runoff,
6 pollution, and degradation of wetlands and riparian zones.
7 Forest lands are managed by a complex array of interests to meet multiple purposes, including providing
8 habitat for a variety of species, recreation, and timber production. While forest is a land cover
9 classification, "timberland" is a land use classification that reflects forest land capable of producing at
10 least 20 cubic feet per acre per year of industrial wood and not withdrawn from timber utilization by
11 statute or regulation. Approximately 504 million acres of U.S. forest land, or 22 percent of the total U.S.
12 land area, qualified as timberland in 2002 (Exhibit 4-5). This total reflects a net gain of about 11 million
13 acres (2 percent) between 1977 and 2002, which FIA attributes largely to reversion of abandoned lands
14 and reclassification of some National Forest lands to align with classifications used on other land
15 ownerships (Smith et al., 2004).
16 The Land Use classification for developed land uses NRI data and is considerably different from the Land Cover
classification for developed which uses NLCD data, as described in Section 4.2.
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1
2
3
4
5
6
7
10
11
Land use varies substantially by EPA Region (Exhibit 4-6). According to the most recent data for each
land use type, Regions 6, 8, and 9 together have more than three-quarters of the nation's grazing land ,
while Region 4 has the largest portion of timberland (27 percent of total U.S. timberland). Trends also
vary widely among regions. Nearly 84 percent of the cropland lost between 1987 and 1997 was in five
EPA Regions (Regions 4, 5, 6, 7, and 8) (Exhibit 4-7, panel A). Increases in developed land are
responsible for part of this decline; for example, developed land increased by nearly 40 percent from 1987
to 1997 in Region 4 (Exhibit 4-7, panel B). Other factors include the federal Conservation Reserve
Program (CRP), which has assisted private landowners in converting about 35 million acres of highly
erodable cropland to vegetative cover since 1985 (as of 2004) (USDA Farm Service Agency, 2004).
Exhibit 4-6. Land use in the U.S. by EPA Region, 1997-2002
FIA
Timberland
(2001)
NASS
Cropland
(2002)
ERS
Rangeland
(1997)
NRI
Developed
(1997)
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10
EPA Region
See text box on page x-xxfor definitions of land use
categories.
EPA Regions
(TJ)
o
Data source: ERS data from vesterby and Krupa, 2001.
FIA data from the USDA Forest Service, Forest
Inventory and Analysis (FIA) Program and from Smith
etal., 2004. NASS data from USDA, 2004. NRI data
from the USDA Natural Resources Conservation
Service and from USDA, 2000.
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Exhibit 4-7. Changes in land use in the U.S. by EPA Region, 1977-2001"
A. Acreage change
ra -2
NRI Developed
(1987-1997)
jLi^
NRI Crop
& pasture
(1987-1997)
'•III
MASS Crop
& pasture
(1997-2002)
"1" "
FIATimberland
(1977-1987) (1987-1997)
I
ll ,
1
(1997-2001)
1
""
B. Percent change
40
c
OS 10
o>
i 0
J2 U
o
1 ~™
°- -30
-40
NRI Developed
(1987-1997)
A"
.,
1 II
NRI Crop
& pasture
(1987-1997)
H"
MASS Crop
& pasture
(1997-2002)
I'll -
(1977-1987)
1
FIATimberland
(1987-1997)
i_
(1997-2001)
'See text box on page x-xx for definitions of land use categories.
Data source: FIA data from the USDA Forest Service, Forest Inventory and Analysis (FIA) Program and from
Smith etal., 2004. MASS data from USDA, 2004. NRI data from the USDA Natural Resources Conservation
Service and from USDA, 2000.
EPA Regions
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Definitions of Land Use Categories for Exhibits 4-5, 4-6, and 4-7
NRI (USDA Natural Resources Conservation Service. 2000b [Appendix 31)
developed: Belonging to one of three land use categories: large urban and built-up areas, small built-up areas, and rural transportation land.
• Large urban and built-up areas. Category composed of developed tracts of at least 10 acres—meeting the definition of Urban and built-
up areas.
• Small built-up areas. Category consisting of developed land units of 0.25 to 10 acres, which meet the definition of Urban and built-up
areas.
• Rural transportation land. Category which consists of all highways, roads, railroads and associated right-of-ways outside urban and
built-up areas; also includes private roads to farmsteads or ranch headquarters, logging roads, and other private roads (field lanes are not
included).
• Urban and built-up areas. Category consisting of residential, industrial, commercial, and institutional land; construction sites; public
administrative sites; railroad yards; cemeteries; airports; golf courses; sanitary landfills; sewage treatment plants; water control structures
and spillways; other land used for such purposes; small parks (less than 10 acres) within urban and built-up areas; and highways, railroads,
and other transportation facilities if they are surrounded by urban areas. Also included are tracts of less man 10 acres that do not meet the
above definition but are completely surrounded by Urban and built-up land. Two size categories are recognized in the NRI: areas of 0.25
acre to 10 acres, and areas of at least 10 acres.
cropland: A land use category that includes areas used to produce adapted crops for harvest. Two subcategories of cropland are recognized:
cultivated and noncultivated. Cultivated cropland is land in row crops or close-grown crops, as well as land (e.g., hayland or pastureland) mat is in a
rotation with row or close-grown crops. Noncultivated cropland includes permanent hayland and horticultural cropland.
pastureland: Land managed primarily for the production of introduced forage plants for livestock grazing. Pastureland cover may consist of a
single species in a pure stand, a grass mixture, or a grass-legume mixture. Management usually consists of cultural treatments: fertilization, weed
control, reseeding or renovation, and control of grazing. For the NRI, this category includes land mat has a vegetative cover of grasses, legumes,
and/or forbs, regardless of whether or not it is being grazed by livestock.
FIA (Smith et al.. 2004)
forest land: Land at least 10 percent stocked by forest trees of any size, including land that formerly had such tree cover and that will be naturally
or artificially regenerated. Forest land includes transition zones, such as areas between heavily forested and nonforested lands that are at least 10
percent stocked with forest trees and forest areas adjacent to urban and built-up lands. Also included are pinyon-juniper and chaparral areas in the
West and afforested areas. A forested area must be at least 1 acre in size to be classified as forest land. Roadside, streamside, and shelterbelt strips of
trees must have a crown width of at least 120 feet to qualify as forest land. Unimproved roads and trails, streams, and clearings in forest areas are
classified as forest if less than 120 feet wide.
timberland: Forest land that is producing or can produce crops of industrial wood and is not withdrawn from timber utilization by statute or
administrative regulation. (Areas qualifying as timberland must be able to produce more than 20 cubic feet per acre per year of industrial wood in
natural stands. Currently inaccessible and inoperable areas are included.)
NASS (USDA National Agricultural Statistical Service. 2004)
cropland: A category including cropland harvested, cropland idle or used for cover crops or soil improvement but not harvested and not pastured,
cropland on which all crops failed, and cropland in cultivated summer fallow. Not included is cropland used only for pasture or grazing.
cropland pasture: Cropland used only for pasture or grazing, which could have been used for crops without additional improvement. Also included
are acres of crops hogged or grazed but not harvested prior to grazing. However, cropland pastured before or after crops were harvested counts as
harvested cropland rather man cropland for pasture or grazing.
pastureland and rangeland: All grazable land—irrigated or dry—that does not qualify as cropland or woodland pasture. In some areas, this is
high-quality pastureland but cannot be cropped without improvements. In others, it can barely be grazed and is only marginally better than waste
land.
ERS (Verterby and Krupa. 2001)
grassland pasture and range: All open land used primarily for pasture and grazing, including shrub and brush land types of pasture; grazing land
with sagebrush and scattered mesquite; and all tame and native grasses, legumes, and other forage used for pasture or grazing. Because of the
diversity in vegetative composition, grassland pasture and range are not always clearly distinguishable from other types of pasture and range. At one
extreme, permanent grassland may merge with cropland pasture; grassland is also often found in transitional areas with forested grazing land.
forest-use land grazed: Forested pasture and range consisting mainly of forest, brush-grown pasture, arid woodlands, and other forested areas that
have grass or other forage growth. The total acreage includes woodland pasture in farms plus estimates of forested grazing land not in farms. For
many states, the estimates include many areas grazed only lightly or sporadically. The Census of Agriculture, the National Resources Inventory,
and the Forest Inventory and Analysis are the principal sources of data (USDA/NASS, 1999a; USDA/NRCS, 2000; USDA/FS, 2000). Historical
data from these and other sources were useful in developing the 140-million-acre approximation.
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1 Indicator Limitations
2 • Estimates are derived from a variety of inventories and samples, conducted over different
3 time periods and for different purposes, which limits the ability to integrate the data and track
4 changes overtime.
5 • NRI does not report land use data for Alaska, which encompasses 365 million acres of the 2.3
6 billion acres nationwide. NRI also does not provide data on federal lands (representing 20
7 percent of the contiguous U.S. land and one third of Alaska). Because federal land is seldom
8 used for agriculture or urban development, and relatively little developed or agricultural land
9 occurs in Alaska, the NRI data likely offer a reasonable approximation of national trends in
10 these categories.
11 • NRI data use three subcategories of types of developed land: large built-up areas, small built-
12 up areas, and rural transportation land. Because ecological effects from developed land
13 depend on the density of development and many other factors, the limited NRI categories are
14 not discriminating enough to support detailed analyses of ecological effects of developed
15 land.
16 • Changes in NRI sampling design currently limit the amount of sub-national data available
17 (e.g., estimates are not available for states in the 2001-2002 timeframe, as they have been
18 previously in five-year increments: 1982, 1987, 1992, and 1997).
19 • The FIA data are aggregated from state inventories in many cases, and dates of data
20 collection for these inventories vary by state—for example, ranging from 1980 to 2001 for
21 reporting 2002 estimates.
22 • Some land uses may not be physically visible, but designated administratively (e.g., lands that
23 are reserved for parks or wilderness may appear similar to lands that are managed for natural
24 resources).
25 • Land use designations are most frequently managed and monitored by local governments,
26 each using different approaches and classifications, making national summaries difficult.
27 • The extent of lands used for energy production, resource extraction or mining is not known
28 and represents a data gap.
29 • Lands specifically protected for certain uses such as wilderness or parks have been
30 periodically inventoried for the nation. These statistics are currently not reported in a form
31 that allows comparison with other statistics.
32 Data Sources
33 Data were obtained from several original sources and compiled by EPA Region. ERS data were obtained
34 from Vesterby and Krupa (2001). FIA data were obtained from the FIA database (USDA Forest Service,
35 2005) (http://www.fia.fs.fed.us/tools-data/data/): some data were also published in Smith et al. (2004).
36 NASS data were published in USDA National Agricultural Statistical Service (2004). Some NRI data are
37 available from an online database (USDA Natural Resources Conservation Service, 2005)
38 (http://www.nrcs.usda.gov/technical/NRI/) and a recent summary report (USDA Natural Resources
39 Conservation Service, 2000); the rest can be obtained on CD.
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1 References
2 Smith, W.B., P.O. Miles, J.S. Vissage, and S.A. Pugh. 2004. Forest resources of the United States, 2002.
3 USDA Forest Service,
4 USDA Farm Service Agency. 2004. The Conservation Reserve Program: summary and enrollment
5 statistics, 2004.
6 USDA Forest Service. 2005. Forest Inventory and Analysis, national FIA data base systems. Accessed
7 2005.
8 USDA National Agricultural Statistical Service. 2004. 2002 census of agriculture, United States summary
9 and state data. Report AC-02-A-51.
10 (QA/QC);
11
12 USDA Natural Resources Conservation Service. 2000. Summary report: 1997 National Resources
13 Inventory (revised December 2000). Washington, DC and Ames, IA: USDA Natural Resource
14 Conservation Service.
15 USDA Natural Resources Conservation Service. 2005. National Resources Inventory. Accessed 2005.
16
17 Vesterby, M., and K.S. Krupa. 2001. Major Uses of Land in the United States, 1997. Statistical bulletin
18 no. 973. U.S. Department of Agriculture, Economic Research Service.
19
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NDICATOR: Urbanization and Population Chan,
2 Population change is a driver affecting numerous environmental outcomes. The total number of people
3 and their distribution on the landscape can affect the condition of the environment in many ways; for
4 example, increasing population often means increased urbanization, including conversion of forest, farm,
5 and other lands for housing, transportation, and commercial purposes. In recent years many communities
6 in the U.S. have seen an increase in developed land area that outpaces population growth. This pattern is
7 of concern for numerous health and environmental reasons (Frumkin et al., 2004). For example, studies
8 indicate that when land consumption rates exceed the rate of population growth, per capita air pollutant
9 emissions from driving tend to be higher. Urbanization and population growth also tend to increase the
10 amount of impervious surfaces and the quantity and types of products that humans produce, use, and
11 discard, thereby affecting waste generation and management, water quality, and chemical production and
12 use.
13 The information presented in this indicator is based on population data collected and analyzed on a
14 decadal basis by the U.S. Census Bureau—as well as annual "intercensal" population estimates—and data
15 collected by the USDA Natural Resources Conservation Service National Resources Inventory (NRI) to
16 track "developed" land (residential, commercial, industrial, and transportation uses). Between 1977 and
17 1997 the NRI developed estimates every five years on non-federal lands in the contiguous U.S. Since
18 2001 the NRI has developed annual estimates, but based on a smaller sample size. This indicator captures
19 trends in overall population growth for both rural and urban populations; the amount of developed land
20 relative to the amount of population change, nationally and by EPA Region; and overall population
21 density, nationally and by EPA Region.
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
22 What the Data Show
Exhibit 4-8. Population and urbanization in the
U.S., 1790-20003
The U.S. population grew from a little over 4 million
people in 1790 to over 281 million in 2000; urban
population is estimated to have grown 1000-fold over
that period (Exhibit 4-8). The population has nearly
doubled since 1950, when the total stood at 150.7
million.
Between 1982 and 2002, the amount of developed land
in the U.S. in the 48 contiguous states (not including
the District of Columbia) and Hawaii grew by more
than 34 million acres, representing a cumulative
increase of approximately 47 percent (Exhibit 4-9).
The Census Bureau estimates that during the same
period, the population of the 48 states grew by slightly
more than 56 million people, or just over 24 percent.
Between 1982 and 2002, the amount of developed land
increased at nearly twice the rate of the population.
300
250
200
'150
• 100
50
1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000
Year
Coverage: 50 states and the District of Columbia.
Data source: U.S. Census Bureau. See specific citations in text.
There are substantial variations in population and development trends in different parts of the U.S.
(Exhibit 4-10). Between 1982 and 1997, EPA Region 4 experienced a 27 percent increase in population
(10.8 million people) and a 55 percent increase in the amount of developed land. This increase in
developed land represents over 8 million acres and nearly 33 percent of the total US increase in acreage
developed during that time. Among the Western EPA Regions (8, 9, and 10), the amount of land
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4-31
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1 developed closely matched population growth. The developed acres per capita actually decreased in the
2 much of the west (Regions 8 and 9). In the Northeast, in contrast, the rate of increase in developed land
3 was nearly four times that of population (Regions 1, 2, and 3). Regions in the Midwest and South
4 (Regions 4-7) fell in-between, with percentage increases in developed land ranging from 1.6 to 3.2 times
5 the rate of population change.
6 Population density also varies across the nation. In 2005, EPA Region 2 was the most densely populated
7 Region, at 512 people per square mile; EPA Region 10 was the least densely populated, with an average
8 of approximately 15 people per square mile (including Alaska) (Exhibit 4-11). The national average in
9 2005 was 83.8 people per square mile. Region 2 has had more than twice the population density of all
10 other EPA Regions for the last fifty years. The largest increase in population since 1950 occurred in
11 Region 9, where population (and density) increased by roughly 280 percent. Region 4 had the second-
12 largest increase, at 140 percent.
13
Exhibit 4-9. Percent change in population
and developed land in the contiguous U.S.
and Hawaii, 1982-2002ab
Exhibit 4-10. Percent change in population and
developed land in the contiguous U.S. and
Hawaii, by EPA Region, 1982-1997a
Change in population
Change in acreage
of developed land
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 All
US
EPA Region
Coverage: Contiguous 48 states
(excluding the District of
Columbia) and Hawaii.
Change in population
Change in acreage
of developed land
Data source: Population data
from the U.S. Census Bureau.
Land use data from USDA Natural
Resources Conservation Service,
National Resources Inventory. See
specific citations in text.
"Coverage: Contiguous 48 states
(excluding the District of Columbia)
and Hawaii.
bBased on changes in the NRI
inventory approach, Hawaii was not
sampled in 2002. Thus, the percent change in developed land
from 1997 to 2002 is based on the 48 contiguous states only.
Data source: Population data from the U.S. Census Bureau. Land
use data from USDA Natural Resources Conservation Service,
National Resources Inventory. See specific citations in text.
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Exhibit 4-11. Population density in the U.S. by EPA Region, 1950-2005"
600, ,
Region 1
Region 2
Region 3
'50'6070'80'90W05 '50'60 70'80'90'00'05 '50'60 70'60'90'00'05 'SOWTO'BO'gO'OO'OS '50'6070'80'90'00'05 '50'6070'80'90W05
EPA Regions
500
400
300
200
100
600
500
400
300
200
100
0
"Coverage: 50 states and the District of Columbia.
Data source: U.S. Census Bureau. See specific citations in text.
Indicator Limitations
Census data:
Region 4
Region 5
Region 6
Region 7
Region 8
Region 9
• •ill
Region 10
All U.S.
'5016070'80'90'00I05 '5016070'80'90'00'05 'SOWTO'SOWOO'OS '50'6070'80'90'00'05
3
4
5
6
9
10
Intercensal figures are estimates based on administrative records of births, deaths, and
migration, and thus differ from the decennial census data in methodology and accuracy.
Sampling and non-sampling errors exist for all Census data as a result of errors that occur
during the data collection and processing phases of the census.
Puerto Rico and Virgin Islands data are not available for all years, and thus have not been
included, affecting the accuracy of the statistics for Region 2.
The criteria for estimating urban population have changed over time as defined by the Census
Bureau.
11 Natural Resources Inventory (NRI) data:
12
13
14
15
16
17
18
19
20
NRI sampling procedures changed in 2000 to an annual survey of fewer sample sites than had
previously been sampled (starting in 1977, NRI sampled 800,000 points every five years).
Fewer sample points mean increased variance and uncertainty and an inability to develop
estimates on a state or regional basis, thus even though national data are available for 2002,
state-level data for compilation at the EPA Regional level are only available through 1997.
State estimates will be available in the future as more points are sampled annually.
NRI collects some data across the entire nation, including Puerto Rico and the Virgin Islands.
Land use statistics, however, are not reported on federal lands or for Alaska and the District
of Columbia.
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1 Data Sources
2 Urban and rural population data for Exhibit 4-8 were obtained from two U.S. Census Bureau publications:
3 data from 1790 to 1990 are from U.S. Census Bureau (1993); 2000 data are from U.S. Census Bureau
4 (2004).
5 In Exhibit 4-9, population change was calculated from annual population estimates published in U.S.
6 Census Bureau (1996, 2002b, 2005) (estimates for 1982/1987, 1992/1997, and 2002, respectively).
7 Changes in acreage of developed land were calculated based on acreage figures reported every five years
8 by the USDA's National Resources Inventory (NRI). NRI data were obtained from two publications
9 (USDA Natural Resources Conservation Service, 2000b and 2004) (1982-1997 and 2002 data,
10 respectively).
11 Exhibit 4-10 is based on annual population estimates by state, published in U.S. Census Bureau (1996 and
12 2002b); and NRI developed land estimates by state, published in USDA National Resources Conservation
13 Service (2000a). The figure was developed by grouping the published state data by EPA Region, then
14 calculating percent change between 1982 and 1997.
15 Population density by EPA Region (Exhibit 4-11) was calculated based on three published datasets:
16 population every 10 years from 1900 to 2000 by state (U.S. Census Bureau, 2002a); population estimates
17 for 2005 by state (U.S. Census Bureau, 2005); and land area by state (U.S. Census Bureau, 2002c).
18 References
19 Frumkin, H., L. Frank, and R. Jackson. 2004. Urban sprawl and public health: designing, planning, and
20 building for healthy communities. Washington, DC: Island Press.
21
24 U.S. Census Bureau. 1993. 1990 census of population and housing: population and unit counts, United
25 States. 1990-CPH-2-1. Washington, DC.
26
27 U.S. Census Bureau, 1996. Intercensal estimates of the total resident population of states: 1980 to 1990.
28 Washington, DC.
29 U.S. Census Bureau. 2002a. Demographic trends in the 20th century: census 2000 special reports.
30 Washington, DC.
31 U.S. Census Bureau. 2002b. Time series of intercensal state population estimates: April 1, 1990 to April
32 1, 2000. Washington, DC. (Table CO-EST2001-12-00)
33
35 U.S. Census Bureau. 2002c. Population, housing units, area, and density for states, 2000. Washington,
36 DC.
37 U.S. Census Bureau. 2004. Statistical abstract of the United States 2004-2005: the national data book.
38 Washington DC.
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1 U.S. Census Bureau. 2005. Annual population estimates 2000 to 2005. Released December 22, 2005.
2 Washington, DC. Available from
3
4 USDA Natural Resources Conservation Service. 2000a. 1997 five-year NRI: acreage and percentage of
5 non-federal land developed. Washington, DC.
6
7 USDA Natural Resources Conservation Service. 2000b. Summary report: 1997 national resources
8 inventory (revised December 2000). Washington, DC and Ames, IA: USDA Natural Resource
9 Conservation Service,
10 USDA Natural Resources Conservation Service. 2004. National resources inventory: 2002 annual NRI.
11
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1 4.3.3 Discussion
2 What These Indicators Say About Trends in Land Use and Their Effects on
3 Human Health and the Environment
4 The indicators point out that the development of land for human residential and commercial purposes is
5 occurring at a rapid pace. In the 20-year period between 1982 and 2002, the acreage of developed land
6 increased by nearly 50 percent from its 1982 level. Population growth in a similar time frame grew at
7 only half the rate of land development, indicating that more land is being developed per capita now than
8 25 years ago. Across EPA regions, such rates of change in developed land and population vary both
9 independently and with respect to each other. Over the same 20-year time frame, the extent of cropland
10 and pastureland has slowly declined, with larger decreases in those regions experiencing either increased
11 land development or reforestation.
12 Limitations, Gaps, and Challenges
13 There is generally a lack of comprehensive data on the types and rates of land use and land cover change,
14 and even less systematic evidence on the causes and consequences of these changes. On a global scale,
15 the National Research Council identified land use dynamics as one of the grand challenges for
16 environmental research.17
17 Two examples of land uses not addressed by the indicators, that can have effects in different ways on
18 condition and extent of land, are the formal protection or reservation of land for habitat or natural
19 resources, and mining and extraction activities. Some data are collected locally and for federal lands (e.g.,
20 National Park acreage) or tracked for economic indicators, but the national picture of the extent of land
21 reservation and mining is not generally available.
22 A key challenge in answering this question is that estimates of the extent of various land uses differ across
23 data sources and each source uses different classifications, measurement approaches, methodologies for
24 analysis and interpretation, and sampling timeframes. The data are collected by many different agencies,
25 which manage land use for many different purposes. The data collection efforts currently in place are
26 derived from specific interests, such as tracking changes in the extent of agricultural or farmland, or
27 understanding how much land is used for timber production. These data collection efforts tend to develop
28 and use their own classifications and categorization, making it difficult to integrate and use the data over
29 time, across inventories, or as a national picture.
30 Another challenge is understanding the effects that trends in land use have on human health. No
31 indicators are available, as effects have not been shown or quantified on a national basis. Urban and
32 landscape planners have conducted site-specific studies on individual land uses, but little is known about
33 overall national trends in land use and potential impacts on human health.
34 An additional challenge is that a variety of state, county, and municipal laws, regulations, and practices
35 govern the use of land, but aside from regulations addressing protection of species and their habitats, there
36 are no national land use regulations that apply to all non-federal lands. There are also relatively few
17 National Research Council, Committee on Grand Challenges in Environmental Sciences. 2001. Grand challenges
in environmental sciences. Washington, DC: National Academy Press.
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1 state-level efforts to organize land use data; most activities occur over specific local, usually urbanizing,
2 geographic areas. This means that land use records are not maintained state-wide or nationally, as they are
3 in other nations, which contributes to challenges in tracking and monitoring land use changes. This also
4 means that strategies to plan land use across jurisdictions are difficult to develop.
5 Finally, a challenge in developing data to determine trends, is that delineation of land use, generally a
6 function of laws, policies, or management designations, may not always be possible to infer from
7 examining the ground via surveys. Analysis of zoning maps or property records at the local level may be
8 necessary.
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1 4.4 WHAT ARE THE TRENDS IN WASTES AND THEIR EFFECTS ON HUMAN
2 HEALTH AND THE ENVIRONMENT?
3 4.4.1 Introduction
4 Every resident, organization, and activity conducted by humans in the United States generates some type
5 of waste. There are many different types of wastes generated, including municipal solid waste,
6 agricultural and animal wastes, medical wastes, radioactive waste, hazardous waste, industrial non-
7 hazardous wastes, construction and demolition debris, extraction and mining wastes, oil and gas
8 production wastes, fossil fuel combustion wastes, and sewage sludge (see the glossary for detailed
9 descriptions of these wastes). In general, waste generation represents inefficient use of materials. These
10 discarded materials, some of which are hazardous, must be managed through reuse, recycling, storage,
11 treatment, and disposal. Hazardous wastes are either specifically listed or identified as hazardous by EPA
12 or a state, or exhibit one or more of the following characteristics: ignitability, corrosivity, reactivity, or
13 toxicity. Generation of hazardous wastes and their management have the potential to contaminate and
14 compromise land and negatively affect human health and environmental conditions. Tracking trends in
15 the quantity, composition, and effects of waste provides insight into the efficiency with which the nation
16 uses (and re-uses) materials and resources and provides a means to better understand the effects of wastes
17 on human health and ecological conditions.
18 The amount of waste produced is influenced by economic activity, consumption, and population growth.
19 Affluent societies, such as the United States, generally produce large amounts of municipal solid waste
20 (e.g., food wastes, single-serving containers, packaged goods, disposable goods, electronics) and
21 commercial and industrial wastes (e.g., demolition debris, incineration residues, refinery sludges). Among
22 industrialized nations, the United States generates the largest amounts of municipal solid waste per person
23 on a daily basis.18
24 Current approaches to waste management evolved primarily due to health concerns and odor control.
25 Waste often was deposited outside of developed areas on nearby lands, frequently wetlands. Excavation
26 of land specifically for deposition of wastes followed, often accompanied by burning of wastes to reduce
27 volume, a practice eventually determined to be a contributor to degraded air quality in urban areas.
28 Burning of wastes occurred at multiple levels, from backyard burning to large, open-burning dumps of
29 municipal solid wastes to onsite burning of commercial and industrial wastes. Land disposal created
30 problems such as groundwater contamination, methane gas formation and migration, and disease vector
31 hazards.
32 The amount of land being used to manage the many types of waste generated is not known. Most
33 municipal solid wastes and hazardous wastes are managed in land disposal units. Land disposal of
34 hazardous wastes includes landfills, surface impoundments, land treatment, land farming, and
35 underground injection. Modern landfill facilities are engineered with containment systems and monitoring
36 programs. Waste management practices prior to RCRA regulations left legacies of contaminated lands in
37 many cases, which are addressed in Section 4.6 of this chapter.
38 Landfills represent one of the largest human-related sources of methane gas in the United States. Between
39 1997 and 2003, landfills accounted for slightly more than one-fourth of the estimated methane emissions
18 Clark, R., andE. Capponi, eds. 2005. OECD in figures 2005: statistics on the member countries. Organization for
Economic Cooperation and Development (OECD) Observer. Paris, France.
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1 attributed to human activity.19 Methane gas is released as wastes decompose, as a function of the total
2 amount and makeup of the wastes, as well as management facility location, design and practices.20 EPA is
3 interested because gas emissions can be affected by recycling and changing product use. For example,
4 recycling aluminum or office paper can reduce environmental effects (e.g., by reducing the need to mine
5 Bauxite or harvest trees), and reduce the amount of waste, thereby reducing greenhouse gas production.21
6 Although data do not exist to directly link trends in waste with effects on human health and the
7 environment, the management of waste may result in waste and chemicals in waste entering the
8 environment. Hazardous waste, by definition, has the potential to negatively affect human health and the
9 environment, which is why it is so strictly regulated. The effects associated with waste vary widely and
10 are influenced by the substances or chemicals found in waste and how they are managed. Priority
11 Chemicals, which are documented contaminants of air, land, water, plants, and animals and are found in
12 waste, have been tracked by EPA since 1991. Between 1991 and 2001, quantities of 17 of the Priority
13 Chemicals were reduced by more than 50 percent.22
14 4.4.2 ROE Indicators
15 The ROE indicators for this question focus on the national trends in the amount of municipal solid waste
16 and hazardous waste generated and their management practices. Municipal solid waste trends are
17 presented for more than four decades. Trends in the generation and management of municipal solid waste
18 are based on estimations from a materials flow, or mass balance approach since 1960. Changes in the
19 amount of RCRA hazardous waste generated and managed are based on mandated biennial submissions
20 from generators and treatment, storage and disposal facilities.
21 Table 4.4.1. ROE Indicators of Trends in Wastes and Their Effects on Human Health and the
22 Environment
23
NATIONAL INDICATORS
Quantity of Municipal Solid Waste Generated and Managed
Quantity of RCRA Hazardous Waste Generated and Managed
LOCATION
4.4.2 -p. 4-40
4.4.2 -p. 4-43
19 U.S. EPA. 2006. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004. EPA 430-R-06-002. April.
20 More information on air emissions related to waste management practices, including nitrogen oxide (NOX) and
carbon monoxide (CO), is included in Chapter 2.
21 U.S. EPA. 2002. Solid waste management and greenhouse gases: a life-cycle assessment of emissions and sinks.
Second edition. EPA/530/R-02/006. Washington, DC.
22 U.S. EPA. 2005. National Priority Chemicals Trends Report (1999-2003). EPA 530-R-05-022. December.
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INDICATOR: Quantity of Municipal Solid Waste Generated and Managed
2 Municipal solid waste (also called trash or garbage) is defined at the national level as wastes consisting of
3 everyday items such as product packaging, grass clippings, furniture, clothing, bottles and cans, food
4 scraps, newspapers, appliances, consumer electronics, and batteries. These wastes come from homes,
5 institutions such as prisons and schools, and commercial sources such as restaurants and small businesses.
6 EPA's definition of municipal solid waste (MSW) does not include municipal wastewater treatment
7 sludges, industrial process wastes, automobile bodies, combustion ash, or construction and demolition
8 debris. Once generated, MSW must be collected and managed, including reuse, recovery for recycling
9 (which includes composting), combustion, and landfill disposal. Many wastes that are disposed in
10 landfills represent a loss of materials that could be reused, recycled, or converted to energy to displace the
11 use of virgin materials.
12 Prior to the 1970s, municipal solid waste disposal generally consisted of depositing wastes in open or
13 excavated landfills, accompanied by open burning to reduce waste volumes. Often industrial wastes were
14 co-disposed with municipal garbage and refuse in urban and rural landfills. Historically, environmental
15 problems associated with landfills have included groundwater contamination, emissions of air pollutants
16 such as toxic fumes and greenhouse gases, land contamination, and increases in vector populations (e.g.,
17 rodents, flies, mosquitoes). Wastes have the potential to cause various types of environmental concerns
18 depending on the way in which they are disposed. Hazardous substances can migrate into the environment
19 causing harm to people and biota; stockpiled scrap tires may ignite, often burning for months and causing
20 air pollution; waste piles can create habitats for pests, e.g., rodents, insects (includes mosquitoes, and
21 other biting-insect pests), or disease vectors; and the physical presence of a waste management area can
22 disrupt an ecosystem. Most wastes generated in the United States are disposed of in landfills, which are
23 subject to federal or state requirements to minimize environmental impacts. Municipal solid waste
24 landfills are discrete areas of land or excavations that receive trash/garbage, as well as various other types
25 of wastes that are not included in this indicator, such as non-hazardous sludges, hazardous wastes from
26 small quantity generators, non-hazardous industrial wastes, municipal wastewater treatment sludges, and
27 construction and demolition debris.
28 This indicator shows trends in the national generation and management of MSW on an annual basis from
29 1960 to 2003. The information presented on MSW consists of estimates generated annually using a
30 materials flow methodology and mass balance approach that relies on production data (by weight) for
31 materials and products that eventually enter the waste stream. These data are collected from industry
32 associations, businesses, and government agencies.
33 What the Data Show
34 The quantity of MSW generated grew steadily from 88 million tons (MT) in 1960 to over 236 MT in
35 2003, an increase of 168 percent (Exhibit 4-12, panel A). During this time, the U.S. population increased
36 by 62 percent (U.S. Census Bureau, 2004). On a per capita basis, MSW generation thus increased from
37 2.7 pounds per person per day in 1960 to 4.5 pounds per person per day in 1990 (panel B). Since 1990,
38 MSW generation has remained around 4.5 pounds per person per day.
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Exhibit 4-12. Municipal solid waste generation
in the U.S., 1960-2003
S 250
£ 200
c
o
100
50
A. Total annual MSW generation
« o
1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
B. Per capita daily MSW generation
1960 1965 1970 1975 1980 1935 1990 1995 2000
Year
Data source: MSW data from U.S. EPA. 2005. Per capita rate based
on population data from U.S. Census Bureau, 2005.
Exhibit 4-13. Municipal solid waste
management in the U.S., 1960-2003
Recovery for composting
Recovery
or recycling
Landfill or other disposal
1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
Data source: U.S. EPA, 2005
Of the 88 MT of MSW generated in 1960, 6 percent
was recovered through recycling and composting, 31
percent was combusted, and 63 percent was landfilled
(Exhibit 4-13). MSW quantities sent to landfills or
other disposal peaked in the mid-1980s at 140 MT and
then began to decline as recycling and combustion
increased. The quantity of MSW disposed of in
landfills has remained fairly constant since 1999 with
an average of 131 MT per year, a 6.6 percent decrease
from the peak years. In 2003, of the 236 MT
generated, 31 percent was recycled, 14 percent was
combusted, and 55 percent was landfilled. Since 1990,
the quantity sent to combustion has held steady at
roughly 14 to 17 percent of generation.
Indicator Limitations
The data in this indicator are derived from
economic statistics on materials
generation and estimates of the lifecycle
of goods, rather than on direct
measurements of wastes disposed. As a
result of this methodology and especially
of differences in definitions, the figures
reported in this indicator do not match
estimates of MSW reported elsewhere
(e.g. BioCycle - which includes
construction and demolition debris,
industrial wastes, agricultural wastes, etc.
in its estimates). However the waste
categories in this indicator are rigorously
defined and consistent from year-to-year,
therefore allowing for reliable long-term
trend analyses.
Landfill data represent the amount of
waste disposed in landfills, but do not
indicate the capacity or volume of
landfills, nor do they indicate the amount
of land used for managing MSW. Land
used for recycling facilities and waste
transfer stations also is not included in
this indicator.
• The data also do not indicate the status or
effectiveness of landfill management or
the extent to which contamination of
nearby lands does or does not occur.
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4-41
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1 Data Sources
2 Exhibits 4-12 and 4-13 were previously published in U.S. EPA (2005). That report also provides tables
3 with numerical values for certain key years during the period of record (1960, 1970, 1980, 1990, 1995,
4 and 2000-2003). However, the full 44-year dataset is not publicly available.
5 Per capita MSW recovery was calculated using published annual estimates of the U.S. resident population
6 (U.S. Census Bureau, 2004 [Table 2]).
7 References
8 U.S. Census Bureau. 2004. Statistical abstract of the United States 2004-2005: the national data book.
9 Washington, DC.
10 U.S. EPA. 2005. Municipal solid waste generation, recycling, and disposal in the United States: facts and
11 figures for 2003. EPA/530/F-05/003.
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NDICATOR: Quantity of RCRA Hazardous Waste Generated and Mana.
2 Hazardous waste is waste with a chemical composition or other property that makes it capable of causing
3 illness, death, or some other harm to humans and other life forms when mismanaged or released into the
4 environment. Historically, uncontrolled dumping of wastes, including hazardous industrial wastes, was
5 commonplace, with numerous entities handling and disposing of these materials. Landfills and surface
6 impoundments containing these materials were unlined and uncovered, resulting in contaminated
7 groundwater, surface water, air, and soil. Even with tight control of hazardous wastes from generation to
8 disposal, the potential exists for accidents that could result in the release of hazardous wastes and their
9 hazardous constituents into the environment. Through the Resource Conservation and Recovery Act
10 (RCRA) and the subsequent 1984 Hazardous and Solid Waste Amendments (HSWA), Congress sought to
11 better control waste management and disposal and to conserve valuable materials and energy resources.
12 Facilities that treat, store, or dispose of hazardous wastes are termed RCRA treatment, storage and
13 disposal facilities (TSDFs). Some hazardous waste generators treat, store, and dispose of their hazardous
14 waste on-site, while others ship their waste to TSDFs. Most hazardous wastes are eventually disposed in
15 landfills, surface impoundments (which eventually become landfills), land application units, or by deep
16 well injection. All hazardous wastes disposed of must meet certain treatment standards required by the
17 Land Disposal Restrictions (LDR) prior to disposal.
18 EPA, in partnership with the states, collects extensive data on the RCRA hazardous waste generation and
19 management practices of TSDFs and large quantity generators (businesses that generate more than 2,200
20 pounds of RCRA hazardous waste, 2.2 pounds of RCRA acute hazardous waste, or 220 pounds of spill
21 cleanup material contaminated with RCRA acute hazardous waste in one month). These data are collected
22 every two years, and this indicator tracks changes in RCRA hazardous wastes generated and managed for
23 the years 1999, 2001, and 2003.
24 What the Data Show
25 Between 1999 and 2003, the quantity of
26 RCRA hazardous wastes generated
27 decreased by 29 percent from 36.1
28 million tons (MT) to 25.8 MT (Exhibit
29 4-14). Due to RCRA hazardous waste
30 regulations and data collection
31 procedures all of the individual
32 management categories discussed below
33 cannot be added together to obtain the
34 total quantity generated. For example,
35 under RCRA, all hazardous waste must
36 be treated to meet technology-based land
37 disposal treatment standards before it is
38 placed in or on the ground, unless the
39 waste, as generated, meets those
40 standards. To minimize the potential to
41 count portions of hazardous waste
42 generated twice, the quantities recovered
43 and quantities disposed of by deep well
Exhibit 4-14. RCRA hazardous waste generation and
management in the U.S., 1999-20033
Generated
Stored/
bulked/
transferred
Material
recovery
Energy
recovery
Treated Disposed
£ 99 '01 t)3 99 '01 T)3 99 W TO 99 T)1 '03 99 fl1 US 99 D1 "03
3 Year
"individual management practice quantities do not add up to the total quantity
generated. See text for details.
Data source: U.S. EPA, RCRAInfo national database
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4-43
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Exhibit 4-15. RCRA hazardous waste
disposal in the U.S. by practice, 1999-2003
20
21
22
23
24
25
26
injection were included, while quantities stored,
transferred, or disposed by landfill, surface
impoundment, land application, or treatment were not
included in the total quantity generated.
In addition to the 36.1 MT of RCRA waste generated
in 1999, another 0.7 MT were
stored/bulked/transferred for some time prior to final
disposition (at which time they would be included in
wastes recovered, treated, or disposed) (Exhibit 4-14).
In 2003, that number rose to 0.8 MT.
Looking at management prior to disposal, in 1999, 7
percent of RCRA hazardous waste was sent to
material recovery activities such as metal or solvent
recovery, while 9 percent fell into this category in
2003 (Exhibit 4-14). The proportion of RCRA
hazardous waste sent for energy recovery increased
from 4 percent of RCRA wastes generated in 1999 to
7 percent in 2003. The proportion sent to treatment
declined from 14 percent in 1999 to 8 percent in 2003.
The quantity of RCRA hazardous wastes ultimately disposed dropped between 1999 and 2003, from 29.4
MTto 21.4 MT; however the relative proportions of waste in the three disposal categories remained fairly
stable (Exhibit 4-15). In both years, 91 to 92 percent of the disposed RCRA hazardous wastes were deep-
well injected. The proportion disposed in landfills or surface impoundments that became landfills also
remained stable at 8 to 9 percent between 1999 and 2003. The land application and land treatment
categories saw a slight decline, but in both years accounted for less than 1 percent of the RCRA
hazardous waste disposed.
£30
o
1 25
Waste disposed (m
0 C/l O O1 O
[004]
2.5
26.9
[002]
2.2
21.6
|0.02|
1.7
19.7
1999 2001 2003
Year
D Land treatment/
land application
D Landfill/surface
impoundment
D Underground
injection
Data source: U.S. EPA, RCRAInfo national database
27 Indicator Limitations
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Data are not collected from small quantity generators (see Introduction), but some wastes
coming from these sources are included in the RCRA hazardous waste management data
from treatment, storage, and disposal facilities that receive the wastes.
Data are limited to wastes referred to as "RCRA hazardous waste" which are either
specifically listed as hazardous or meet specific ignitability, corrosivity, reactivity, or toxicity
criteria found in the U.S. Code of Federal Regulations Title 40, Part 261. Materials that are
not wastes, whether hazardous or not, are not regulated by RCRA nor included in the data
summarized here.
States have the authority to designate additional wastes as hazardous under RCRA, beyond
those designated in the national program. State-designated hazardous wastes are not tracked
by EPA or reflected in the aggregated information presented.
The comparability of year-to-year amounts of RCRA hazardous waste generated and
managed can be influenced by factors such as delisting waste streams (i.e., determining that a
particular listed waste stream coming from a particular facility is not hazardous) or removing
the hazardous characteristic of a waste stream.
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1 • Most hazardous waste generated in the US is in the form of wastewater. The majority of these
2 wastewaters are: 1) sent untreated to publicly-owned treatment works (POTW); 2) treated and
3 sent to a POTW; or 3) discharged directly to surface waters through a National Pollutant
4 Discharge Elimination System (NPDES) permit. Hazardous wastewaters generated and
5 subsequently sent to POTWs or discharged through a NPDES permit are not included in this
6 indicator. Any materials generated from these processes, such as sludge, that are considered
7 hazardous waste are managed under hazardous waste regulations.
8 Data Sources
9 This indicator is based on data reported by individual facilities, which can be found in EPA's RCRAInfo
10 database (U.S. EPA, 2005) (http://www.epa.gov/epaoswer/hazwaste/data/index.htmtfrcra-info).
11 References
12 U.S. EPA. 2005. RCRAInfo national database. Data as of August 31, 2005.
13
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1 4.4.3 Discussion
2 What These Indicators Say About Trends in Wastes and Their Effects on
3 Human Health and the Environment
4 The indicators show that municipal solid waste generation in the United States continued to rise between
5 1960 and 2003, both in absolute terms and on a per capita basis. However, since 1990, the daily per capita
6 generation of municipal solid waste has been relatively constant showing that the total increase in waste is
7 a function of population growth. On the other hand, hazardous waste, which is primarily generated
8 through industrial processes, decreased to some extent in the time period shown from 1999-2003
9
10 Materials recovery, or recycling, is an important component of waste management, as it takes materials
11 that might be considered waste and removes them from the cycle to generate re-usable marketable
12 materials for manufacturing. Recycling efforts related to municipal solid waste have increased over the
13 four decades showing the steepest increases between 1980 and 2000, most likely due to the increased
14 awareness about the benefits of recycling and the implementation of policies by state and local
15 governments tying waste generation directly to the cost of waste services. Municipal solid waste recycling
16 efforts have been steady since 2000, with nearly a third of all municipal solid waste being recycled or
17 composted.
18
19 Recycling of hazardous wastes has remained relatively constant over the time span represented by the
20 indicators, although there has been a decrease in the amount of waste sent for materials recovery and an
21 increase in the amount of waste sent for energy recovery.
22
23 Although recycling is on the rise, most wastes are disposed. Disposal of municipal solid wastes in
24 landfills saw a rise from 1960 to the early 1980s, with dips in 1975 and 1982. During the early 1990s
25 disposal declined, but then began to rise again in the late 1990s and has fluctuated since. Similarly, most
26 hazardous wastes are also land disposed, although they are required to meet strict standards for protecting
27 human health and the environment prior to disposal.
28 Limitations, Gaps, and Challenges
29 While numerous waste-related data collection efforts exist at the local, state and national levels, none
30 result in nationally consistent or comprehensive data to provide a full understanding of the amount and
31 locations of waste generation and management.
32 The two types of waste addressed in the indicators represent only a small percentage of the total amount
33 of waste generated in the United States. Other types of waste comprise the majority of total waste
34 generated, although exact amounts and percentage of total waste are unknown. Quantities of "end-of-
35 stream" wastes, such as municipal solid waste, provide an indication of changing trends in consumption
36 and economic growth, but do not provide information on the other amounts of waste generated by up-
37 stream activities, including resource extraction and manufacturing. EPA is interested in better
38 understanding the comparative amounts of the various types of waste generated, but national data are
39 dated, inconsistent, or generally not available in common units to develop a comprehensive picture of the
40 waste generated in the United States.
41 The amount of waste generated and managed may describe ambient conditions in terms of wastes in the
42 environment, but does not provide any indication of the effects on human health or environmental
43 condition. There have been changes in the management of wastes over the past few decades, designed to
44 reduce hazardous and potential exposures, but data that more concretely measure the overall exposure and
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1 therefore effects on human health and the environment caused by wastes and waste management practices
2 are still lacking.
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1 4.5 WHAT ARE THE TRENDS IN CHEMICALS USED ON THE LAND AND THEIR
2 EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT?
3 4.5.1 Introduction
4 Many chemicals and chemical products are considered essential to modern life because of the benefits
5 they provide. Some break down quickly, while others persist for long periods of time in the environment
6 and may bioaccumulate in the food chain (e.g., persistent, bioaccumulative toxics [PBTs]).
7 Introduction of chemicals into the environment occurs through acts of nature (e.g., volcanoes, hurricanes),
8 spills on land, emissions to air, and discharges to water. Chemicals can be released through large- and
9 small-scale industrial and manufacturing activity, in the production and storage of food and consumer
10 products, and in efforts to manage or eradicate insect-borne diseases (e.g., West Nile virus, Lyme
11 disease), or through personal actions such as use of and improper disposal of household products (e.g.,
12 lawn care materials, pharmaceuticals, cleaning products, batteries, paint, automotive products) or wastes.
13 Deliberate application of chemicals to the land is widespread in agricultural production to increase crop
14 yields and control fungi, weeds, insects, and other pests.
15 Tracking trends in the use and disposition of chemicals in the United States is important to better
16 understand the potential for those chemicals to affect human health and the environment. Many chemicals
17 pose little known hazard to human health or environmental condition, while others pose risk. Many
18 chemicals are recognized as carcinogens.23 The effects of chemicals on human health and other ecological
19 receptors through environmental exposure can be acute and very toxic, subtle and cumulative overtime,
20 or nonexistent. Chemicals can be of concern because of their pervasiveness, potential to accumulate,
21 possibilities of interaction, and often long-term unknown effects on people and the environment (e.g.,
22 cancer, mercury in fish). Humans and wildlife may be affected by certain chemicals through direct
23 exposure, including accidental ingestion or inhalation, accumulation and uptake through the food chain,
24 or dermal contact.
25 Similarly, ecosystems and environmental processes may be compromised or contaminated through the
26 migration and accumulation of chemicals (e.g., via uptake by plants, fugitive dust and volatilization, and
27 migration to water supplies). For example, excessive nutrient loading from over-fertilization can result in
28 runoff that causes adverse effects in aquatic ecosystems.24 Widespread exposures to, or misuse of
29 pesticides can harm non-targeted plants and animals (including humans), as well as lead to development
30 of pesticide-resistant pest species.
31 It is difficult to make generalizations about the effects of chemicals and chemical usage, not only because
32 there are thousands of chemicals, but also because individual chemicals have unique ways of being
23 U.S. Department of Health and Human Services. 2005. Report on carcinogens. Eleventh edition. Washington, DC:
Public Health Service, National Toxicology Program.
24 Boesch, D.F., D.M. Anderson, R.A. Homer, S.E. Shumway, P.A. Tester, and T.E. Whitledge. 1997. Harmful algal
blooms in coastal waters: options for prevention, control, and mitigation. NOAA coastal ocean program decision
analysis series no. 10.
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1 absorbed and handled by living organisms. The risks associated with chemicals are dependent on many
2 factors, including exposure and toxicity-which can be acute or chronic-and can occur at multiple stages
3 of the chemical life cycle. Different stages in the life cycle of chemicals, such as manufacturing, transport,
4 application or use, runoff, or accumulation pose different hazards to humans and the environment.
5 4.5.2 ROE Indicators
6 The amounts and types of chemicals applied or released to land through agricultural fertilizers are
7 examined as a National Indicator displayed at EPA Regional scale. Three other National Indicators are
8 examined, including toxic chemicals in production related wastes, pesticide residues in food, and
9 occurrences of pesticide-related injury and illness (Table 4.5.1).
10 Trends in the amount of fertilizer used are based on sales data provided by major crop-producing states
11 through an annual survey conducted since 1960. Acreage estimates are from an agricultural census of the
12 48 contiguous states which has been conducted every five years since 1954. Trends in the quantities of
13 Toxics Release Inventory (TRI)-reported chemical releases are based on annual reports required since
14 1998 from facilities that meet certain size and usage criteria. Trends in the detection of pesticide residues
15 in food are derived from randomly sampled data collected daily since 1993 from participating states for
16 over 50 different commodities. Trends in reported pesticide incidents are from a pesticide surveillance
17 system that collects data annually from Poison Control Centers around the nation.
18 Table 4.5.1. ROE Indicators of the Trends in Chemicals Used on the Land and Their Effects on
19 Human Health and the Environment
INDICATORS
Fertilizer Applied for Agricultural Purposes (N/R)
Toxic Chemicals in Production-Related Wastes Released, Treated,
Recycled, or Recovered for Energy Use
Pesticide Residues in Food
Reported Pesticide Incidents
LOCATION
4.5.2 -p. 4-50
4.5.2 -p. 4-54
4.5.2 -p. 4-58
4.5.2 -p. 4-61
20 N/R = National Indicator displayed at EPA Regional scale
21
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INDICATOR: Fertilizer Applied for Agricultural Purposes
2 Commercial fertilizers are applied to agricultural crops to increase crop yields. Prior to the 1950s, most
3 farming occurred on small family farms with limited use of chemicals. The shift since then to larger
4 corporate farms has coincided with the use of chemical fertilizers in modern agricultural practices. The
5 three major types of commercial fertilizer used in the United States include nitrogen, phosphate, and
6 potash.
7 Nitrogen (N) is found primarily in the organic fraction of soils, but can also occur as nitrate. Nitrate is
8 both extremely soluble and mobile and can lead to nuisance algal growth, mostly in downstream
9 estuaries, and cause contamination of drinking water. Phosphorus (P) occurs in soil in several forms, both
10 organic and inorganic. Phosphorus loss in sediment due to erosion is common and phosphate, while less
11 soluble than nitrate, can easily be transported with soil in runoff. Phosphorus/phosphate runoff can lead to
12 nuisance algae and plant growth, often in freshwater streams, lakes, and estuaries. Potash is the oxide
13 form of potassium (K) and its principal forms as fertilizer are potassium chloride, potassium sulfate, and
14 potassium nitrate. When used at recommended application rates, there are few to no adverse effects from
15 potassium, but it is a common component of mixed fertilizers used for high crop yields and is tracked in
16 the fertilizer use surveys conducted.
17 This indicator shows use of the three major fertilizers (expressed as N, P, or K) in pounds per acre of land
18 used for crop production per year from 1960 to 2003. Data are from an annual survey for agricultural
19 crops conducted by the United States Department of Agriculture (USDA) National Agricultural Statistics
20 Service (NASS) and from the Economic Research Service's Major Land Use series. Acreage used for
21 crop production includes cropland harvested and crop failure as estimated by the NASS series. Cropland
22 estimates as used in this indicator are a subset of agricultural land estimates discussed in the Land Cover
and Land Use indicators. NASS also produces an
annual Agricultural Chemical Usage report of 4-5
targeted field crops that is based on data compiled
from the Agricultural Resources Management Survey
(ARMS). The ARMS surveys farmers in major
agriculture producing states that together account for a
large percentage of crop acreage for corn, soybeans,
and cotton. Results are presented for year 2000 by
EPA Region.
Exhibit 4-16. Commercial fertilizer use in the
U.S., 1960-20038
I 140
« 120
| g 100
is.80
I I 60
=• 40
20
— 0
1960
Total
Potash
Phosphate
1970
1980
Year
1990
2000
aBased on sales data. Per-acre use based on the acreage of
harvested or failed cropland, as determined by USDA's National
Agricultural Statistics Service.
Data source: USDA Economic Research Service and USDA National
Agricultural Statistics Service. See specific citations in text.
What the Data Show
Based on fertilizer sales data, NASS estimates show
that total use of the three major commercial fertilizers
has steadily increased, from 46.2 nutrient pounds per
acre per year (Ibs/acre/yr) in 1960 to 130.9 Ibs/acre/yr
in 2003, an increase of 183 percent (Exhibit 4-16).
During this period, cropland used for crop production
generally has fluctuated between 300 and 350 million
acres with the largest increases occurring between
1972 (296 million acres) and 1981 (357 million acres)
(Vesterby and Krupa, 2001). Following this increase,
federal land conservation programs were instituted
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4-50
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
that removed cropland from production and decreased acreage harvested by 16 percent. Since 1996,
cropland used for crop production has remained between 321 and 328 million acres (Vesterby and Krupa,
2001). Aggregate commercial fertilizer use has fluctuated between 121 and 142 Ibs/acre/yr over the last
twenty years, with peak usage in 1994. Since 1960, nitrogen accounted for the steepest increase in use,
from 17.0 Ibs/acre/yr to 73.8 Ibs/acre/yr in 2003, and now accounts for over 56 percent of total fertilizer
use, up from nearly 37 percent in 1960. During the same period, phosphate and potash use grew more
slowly and remained steady between 25 and 36 Ibs/acre/yr each since the late 1960s. Both phosphate
(down 20 percent) and potash (down 15 percent) usage declined on a per acre basis since reaching their
peak usages in the 1970s, and now account for approximately 20 percent and 24 percent of total fertilizer
usage, respectively.
Estimates from annual NASS Acreage reports show
that similar amounts of land have been planted with
corn each year since 1995. Since 1995, the acreage
planted in corn has totaled between 77 and 80 million
acres, an increase from 66 million acres planted in
1970 (USDA, 2004). While grown in most states, corn
production is concentrated in the middle of the country
(EPA Regions 5 and 7). The acreage of land planted in
cotton was 15.5 million acres in 2000 and has
averaged between 12-14 million acres since 1990.
Major cotton-producing states include 17 southern
states located in EPA Regions 4, 6, and 9. Soybeans
represent the fastest growing crop in total acreage,
increasing from 57.8 million acres in 1990 to 74.3
million acres in 2000 (USDA National Agricultural
Statistics Service, 2004). The majority of soybean
acreage (80 percent) is concentrated in the upper
Midwest in EPA Regions 5 and 7.
Overall, production of these three crops in the ARMS
states used slightly more than 10.8 MT/yr of fertilizer
in 2000 (Exhibit 4-17), or about one half of the 21.6
MT/yr estimated by USDA's Economic Research
Service for all crops produced in the entire United
States. Of this amount, slightly less than half (5.25
MT/yr) was applied in EPA Region 5 (Exhibit 4-17),
most of which was used for corn. An additional 3.2
MT/yr was applied in EPA Region 7, primarily on
corn or soybeans. Most of the remaining fertilizer was
used in EPA Regions 4 and 6, primarily on cotton.
Exhibit 4-17. Fertilizer use for three
common crops (corn, cotton, and soybeans)
in major agriculture-producing states, by
EPA Region, 2000a
o B
£
•1 5
= A
E
<» 2
en
^ 1
t n
n Potash
n Phosphate
n Nitrogen
p=|
F=l
R2 R3 R4 R5 R6 R7
EPA Region
R8
R9
Coverage: States surveyed by EP* Regions
USDA's Agricultural Resource
Management Survey (ARMS)
Program in 2000 for corn, cotton,
and soybeans. Each commodity
was surveyed in a different subset
of states, which together account
for a substantial portion of the
nation's production of that
particular commodity. No states in Regions 1 or 10 were surveyed
by the ARMS Program for corn, cotton, or soybeans.
Data source: USDA National Agricultural Statistics Service, 2001
40 Indicator Limitations
41
42
43
44
45
• USDA national estimates of fertilizer use are based on sales data provided by states, and not
on actual fertilizer usage, and are susceptible to differing reporting procedures or accuracy
from state to state.
• Data to identify cropland used for crop production are from the major land use series which is
based on the 48 contiguous states and include unpublished NASS data.
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1 • Within the ARMS, not all states report fertilizer data every year for each crop type, making it
2 difficult to establish year-to-year trends (a decrease in fertilizer use for a specific crop might
3 be attributed to failure of a state to report, rather than an actual decrease of use).
4 • ARMS sampling is limited to program states, which represent 83 to 98 percent of crop
5 acreage (across all surveyed crops) for the year 2000, depending on crop type.
6 • The NASS Acreage report has estimates of acreage in production for the entire nation by
7 crop, while fertilizer sales data are based only on USDA program states. Even though USDA
8 program states represent the majority of U.S. planted acreage (often over 90 percent), the
9 ability to generalize the data to the country as a whole is unknown, as non-program states,
10 while representing a small percentage of a crop, might have much different application rates
11 due to climate, weather, etc.
12 • Fertilizer applied to trees that are considered agricultural-type crops (e.g., nut producing
13 trees) are included in field crop summaries; but fertilizer applied in silviculture (e.g., southern
14 pine plantations) are not covered by the NASS data collection system.
15 • Loading of nutrients in aquatic systems is not necessarily correlated directly with fertilizer
16 use, but rather to the levels of fertilizer applied in excess of amounts used by crops, natural
17 vegetation, and soil biota.
18 Data Sources
19 Exhibit 4-16 is based on two sets of summary data from the USDA's Economic Research Service. Annual
20 estimates of fertilizer use from 1960 through 1998, by nutrient, were obtained from USDA Economic
21 Research Service (2003); unpublished post-1998 data were obtained via e-mail correspondence (Wen
22 Huang, WHUANG@ers .usda.gov). Fertilizer use per acre was calculated based on annual estimates of the
23 amount of cultivated (harvested or failed) cropland from 1960 to 2003 published in Lubowski et al.
24 (2006) [see summary tables, http://www.ers.usda.gov/Data/MajorLandUses/MLUsummarytables.pdf].
25 Exhibit 4-17 is based on fertilizer use data from USDA's 2000 ARMS survey, which were obtained from
26 USDA National Agricultural Statistics Service (2001). The published data are by state, so additional
27 aggregation was required to report by EPA Region.
28 References
29 Lubowski, R.N., M. Vesterby, S. Bucholtz, A. Baez, and M.J. Roberts. 2006. Major uses of land in the
30 United States, 2002. Economic Information Bulletin No. (EIB-14). U.S. Department of Agriculture,
31 Economic Research Service,
32 USDA Economic Research Service. 2003. Agricultural resources and environmental indicators report.
33
34 USDA National Agricultural Statistics Service. 2001. Agricultural chemical usage, 2000 field crops
35 summary,
36 USDA National Agricultural Statistics Service. 2004. Acreage.
37
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1 Vesterby, M, and K.S. Krupa. 2001. Major Uses of Land in the United States, 1997. Statistical bulletin
2 no. 973. U.S. Department of Agriculture, Economic Research Service.
3
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INDICATOR: Toxic Chemicals in Production-Related Wastes Released, Treated,
Recycled, or Recovered for Energy Use
3 Toxic chemicals are contained in waste materials produced by a wide variety of industrial activities, in
4 both public (e.g., sewage treatment plants) and private facilities. These chemical wastes are really a
5 composite matrix of various chemicals, some of which may be hazardous or toxic, and therefore are
6 subject to reporting under the Toxics Release Inventory (TRI) program. Some of these chemicals are
7 released onsite or offsite to air, water, or land (including surface impoundments and underground
8 injection wells). The rest are treated, recycled, or combusted for energy recovery. Reductions in the
9 quantities of TRI chemicals are desirable from both environmental and economic perspectives. TRI
10 chemicals have known toxic properties rendering them potentially hazardous to workers in both
11 production and waste management facilities, and more generally to ecosystems and human health. As
12 elements of overall business strategies, companies target waste reduction in ways that reduce costs and
13 increase profits.
14 This indicator tracks trends in the amounts of toxic chemicals in production-related wastes that contain
15 reported TRI chemicals which are either released to the environment, or are treated, recycled, or
16 combusted for energy recovery. Toxic chemicals in non-production related waste, such as might be
17 associated with catastrophic events and remedial actions (cleanup), are not included in this indicator
18 because they are not directly related to routine production practices.
19 TRI contains information on more than 650 chemicals and chemical categories from nine industry sectors,
20 including manufacturing operations, certain service businesses, and federal facilities. Facilities are
21 required to report to TRI if they employ 10 or more employees, have a TRI-covered Standard Industrial
22 Classification code, and manufacture or process more than 25,000 pounds or otherwise use more than
23 10,000 pounds of the 650 listed chemicals during a calendar year (U.S. EPA, 2002b). In 2003, almost
24 24,000 facilities reported to TRI (U.S. EPA, 2005a).
25 TRI is national in coverage and includes all U.S. territories. Because the reporting requirements for TRI
26 have varied somewhat between 1998 and 2003 (the most recent year for which annual data reports are
27 available in TRI), only chemicals that were reported consistently from year to year over this period are
28 included in this indicator. A key category of chemicals in wastes omitted in this analysis is Persistent,
29 Bioaccumulative and Toxic (PBT) chemicals. Facilities that manufacture, process, or otherwise use PBT
30 chemicals have lower reporting thresholds, which were established in 2000 and 2001, making the
31 comparison with earlier datasets difficult. Metal mining sector land releases are analyzed separately
32 because a 2003 court decision altered the scope of TRI reporting of these quantities (U.S. EPA, 2004).25
33 What the Data Show
34 In 2003 the quantities of TRI chemicals associated with production-related wastes tracked in this indicator
35 totaled 23.9 billion pounds (Exhibit 4-18). These quantities have decreased by more than 4 billion pounds
36 (14.3 percent) since 1998. The decrease was gradual overtime with the exception of the year 2000, which
37 saw an increase of 4.3 billion pounds from the previous year, followed by a return to prior levels and
25 The metal mining sector consists of facilities that fall within Standard Industrial Classification Code 10 and must
report to the Toxics Release Inventory in accordance with Section 313 of the Emergency Planning and Community
Right to Know Act.
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
reduction trends in 2001. The 2000 increase is
attributed to a few facilities that reported large
amounts of onsite treatment and onsite recycling (U.S.
EPA, 2002a).
Excluding metal mining releases to land,
approximately 3.1 billion pounds (13.4 percent) were
released offsite or onsite to air, land, or water in 2003
(Exhibit 4-19). The remaining 20 billion pounds (86.6
percent) were managed (onsite or offsite) through
treatment, recycling, and energy recovery processes
(Exhibit 4-18). The 3.1 billion pounds of
environmental releases and offsite releases in 2003
were 18.6 percent less than the amount reported in
1998 (Exhibit 4-19). The 20 billion pounds otherwise
managed in 2003 represent a 5.7 percent decline from
1998 (Exhibit 4-18).
Between 1998 and 2003 there were also distinct trends
in media-specific and offsite releases (Exhibit 4-19).
Air releases declined steadily between 1998 and 2003
by 24.2 percent (504 million pounds). Releases to
surface waters increased by 14.7 million pounds
between 1998 and 1999, but between 1998 and 2003
dropped by a net total of 12.8 percent (32.6 million
pounds). Excluding metal mining, land releases
declined by 260 million pounds (24.5 percent) since
1998. Offsite releases, which cannot be apportioned by
media in TRI, rose steadily by 22.5 percent (90.3
million pounds) over the 1998 to 2003 period.
Exhibit 4-18. Quantities of toxic chemicals
released, recycled, recovered for energy, and
treated in the U.S., as reported to EPA's Toxics
Release Inventory, 1998-2003a'b
n o m
*3 C*3 CM
(spunod UQJI
Toxic chemicals (bi
_L _L po
3 01 o cn o
28.0
6.8
8.3
3.6
9.2
28.0
6.9
9.0
3.4
8.6
32.3
6.3
12.8
3.6
9.6
25.9
5.2
8.4
3.5
8.9
24.9
4.3
7.9
3.7
9.0
n Q
4.0
8.1
3.4
8.4
1998 1999
2000 2001
Year
2002 2003
"Coverage: Production-related waste from
facilities required to report to EPA's Toxics
Release Inventory (TRI). More than 650
chemicals and chemical categories are
reportable to TRI. This indicator does not
cover TRI chemicals designated as PBTs
(persistent, bioaccumulative, and toxic), as
PBT reporting thresholds were changed midway through the
period of record.
bSome waste quantities may be double-counted when waste has
been transferred from one TRI facility (which has counted waste
as offsite disposal or as other releases) to another TRI facility
(which has counted transferred waste as onsite disposal or as
releases to air, land, or water).
Data source: U.S. EPA, 2005
Exhibit 4-19. Quantities of toxic chemicals released in the U.S., by type of release, as reported to
EPA's Toxics Release Inventory, 1998-2003ab
Onsite land releases
Onsite water releases
(surface water discharges)
(excluding metal mining sector)
0.40 0.43 0-19 0.49 0.47 0.49
0.27 0.27 0.23 0.23 0.22
98 99 '00 '01 D2 '03 96 99 TO D1 '02 TO
98 '99 '00 '01 TO '03
98 99 DO T)1 '02 TO
"Coverage: Production-related waste from facilities required to report to EPA's Toxics Release Inventory (TRI). More than 650 chemicals and
chemical categories are reportable to TRI. This indicator does not cover TRI chemicals designated as PBTs (persistent, bioaccumulative, and
toxic), as PBT reporting thresholds were changed midway through the period of record.
bSome waste quantities may be double-counted when waste has been transferred from one TRI facility (which has counted waste as offsite
disposal or as other releases) to another TRI facility (which has counted transferred waste as onsite disposal or as releases to air, land, or water).
Data source: U.S. EPA, 2005
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Exhibit 4-20. Quantities of toxic chemicals
released by the metal mining sector, as
reported to EPA's Toxics Release Inventory,
1998-2003ab
s
11
3.180
1998 1999 2000 2001 2002 2003
Offsite releases 0.001 0.002 0.001 0.001 0.001 0.001
Onsite air releases 0.004 0.005 0.003 0.003 0.003 0.003
Onsite land releases 2.983 3.172 2.556 1.910 1.192 0.887
0.001 0.000 0.000 0.000 0.001 0.001
Onsite water
releases (surface
water discharge)
Total
2.989 3.180 2.560 1.913 1.197 0.891
"Coverage: Production-related waste from facilities In the metal
mining sector that are required to report to EPA's Toxics Release
Inventory (TRI). More than 650 chemicals and chemical
categories are reportable to TRI. This indicator does not cover
TRI chemicals designated as PBTs (persistent, bloaccumulatlve,
and toxic), as PBT reporting thresholds were changed midway
through the period of record.
bSome waste quantities may be double-counted when waste has
been transferred from one TRI facility (which has counted waste
as offsite disposal or as other releases) to another TRI facility
(which has counted transferred waste as onsite disposal or as
releases to air, land, or water).
Data source: U.S. EPA, 2005
38 Indicator Limitations
The metal mining sector accounted for 38 percent of
the total production-related wastes released to the
environment over the six-year period 1998-2003,
releasing approximately 12.7 billion pounds of total
production-related wastes (Exhibit 4-20), compared to
20.8 billion pounds reported by all other industry
sectors (Exhibit 4-19). Nearly all of the production-
related wastes managed by metal mining facilities
were releases to land. There is a substantial downward
trend for the quantities of total releases reported by the
metal mining sector from 2001 to 2003 (Exhibit 4-20).
In 2001, the metal mining industry reported nearly 2
billion pounds in total releases, and in 2003, only 0.89
billion pounds were reported, but part of this trend can
be attributed to the court decision (Barrick Goldstrike
Mines, Inc. v. EPA) in 2003 that excluded mine
overburden as a reportable waste (U.S. EPA, 2004).
There are less dramatic trends among treatment,
energy recovery, and recycling over the six-year
period (Exhibit 4-18). The amount of TRI chemicals
reported as treated declined by 185 million pounds
(2.2 percent) from 1998 to 2003 (from 8.3 to 8.1
billion pounds). There were large variations in the
amount treated during this period, from a high of 12.8
billion pounds in 2000 to a low of 7.9 billion pounds
in 2002. The amount of TRI chemicals recycled
declined by 844 million pounds (9.2 percent) from
1998 to 2003, varying from a high of 9.6 billion
pounds in 2000 to a low of 8.4 billion pounds in 2003.
TRI chemicals managed through energy recovery
processes showed a decline of 179 million pounds (4.9
percent) in the six-year period, with less fluctuation,
from a high of 3.7 billion pounds in 2002 to a low of
3.4 billion in 2003. Some of the year-to-year
fluctuations may reflect changes in aggregate
production levels in the national economy.
39
40
41
42
43
44
45
TRI data reflect only "reported" chemicals, and not all chemicals with the potential to affect
human health and the environment. TRI does not cover all toxic chemicals or all industry
sectors. The following are not included in this indicator: (1) toxic chemicals that are not on
the list of approximately 650 toxic chemicals and toxic chemical categories, (2) wastes from
facilities within industrial categories that are not required to report to TRI, and (3) releases
from small facilities with fewer than ten employees or that manufactured or processed less
than the threshold amounts of chemicals.
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1 • TRI chemicals vary widely in toxicity, meaning that some low-volume releases of highly-
2 toxic chemicals might actually pose higher risks than high-volume releases of less toxic
3 chemicals. The release or disposal of chemicals also does not necessarily result in the
4 exposure of people or ecosystems.
5 • Lead compounds are not included in the indicator because of a change in the reporting
6 threshold in 2001. Vanadium releases were measured beginning in 2001; because the overall
7 amounts were small relative to the other wastes, they are included in the 2001 to 2003 data.
8 • PBT chemicals are not included in this indicator because of a change in reporting thresholds
9 during the period. They are of particular concern because they are toxic, they remain in the
10 environment for long periods of time because they are not readily destroyed, and they build
11 up or accumulate in body tissue.
12 • National trends in wastes released to the environment are frequently influenced by a dozen or
13 so large facilities in any particular reporting category. These trends may not reflect the
14 broader trends in the 2,500 smaller facilities that report to TRI each year.
15 Data Sources
16 This indicator is based on data from EPA's TRI Explorer database (U.S. EPA, 2005b), an online tool that
17 allows users to generate customized reports on toxic releases reported to TRI.
18 References
19 U.S. EPA. 2002a. 2000 Toxics Release Inventory (TRI) public data release report. EPA/260/R-02/003.
20
21 U.S. EPA. 2002b. 2000 Toxics Release Inventory (TRI) public data release report, Executive Summary.
22 EPA/260/S-02/001
23 U.S. EPA. 2004. EPA analysis of decision in Barrick Goldstrike Mines, Inc. v. Whitman. Accessed
24 December 20, 2005. (See also
25 http://www.nma.org/pdf/tri/barrick_decision040203.pdf)
26 U.S. EPA. 2005a. 2003 Toxics Release Inventory: public data release report. EPA/260/R-05/001.
27
28 U.S. EPA. 2005b. TRI explorer. Updated June 8, 2005; accessed August 10, 2005.
29
30
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NDICATOR: Pesticide Residues in F<
2 Pesticides are substances or mixtures of substances intended for preventing, destroying, repelling, or
3 mitigating plant or animal pests and may include herbicides, insecticides, fungicides, and rodenticides.
4 More than one billion pounds of pesticides are used in the United States each year to control weeds,
5 insects, and other organisms that threaten or undermine human activities (Aspelin, 2003). Some of these
6 compounds can be harmful to humans if sufficient quantities are ingested, inhaled, or otherwise contacted
7 (see the Urinary Pesticide indicator, p. 5-94). Potential health effects and primary exposure routes vary by
8 chemical. The most common routes of exposure for the general population are ingestion of a treated food
9 source and contact with applications in or near residential sites. Pesticides may also be harmful in the
10 environment when non-target organisms are exposed (U.S. EPA, 2003).
11 This indicator represents data from the U.S. Department of Agriculture's Pesticide Data Program (POP)
12 which measures pesticide residue levels for more than 290 pesticides and their metabolites in fruits,
13 vegetables, grains, meat, and dairy products from across the country, sampling different combinations of
14 commodities each year. The analysis examines pesticides currently on the market and also includes
15 continued testing for some persistent and bioaccumulative pesticides that have been banned since the
16 1970s, such as aldrin/dieldrin, heptachlors, and DDT and its metabolites. POP data collection began in
1991 and includes both domestic and foreign-
produced commodities. Results are published in
annual reports, which include statistics on the number
of pesticide residues detected, the number of residues
exceeding the tolerance established by EPA for a
given pesticide-commodity pair (Code of Federal
Regulations, Title 40, Part 180), and the number of
residues detected for which no tolerance has been
established. This indicator depicts data from 1994 to
2003; data prior to 1994 are considered less reliable.
Between 1994 and 2003, the number of food samples
analyzed per year ranged from 5,771 (1996) to 12,899
(2002), with a general increase over time.
Exhibit 4-21. Pesticide detections in food in the
U.S., 1994-2003"b
100
80
60
40
20
1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
2003
"Coverage: Based on a survey of fruits,
vegetables, grains, meat, and dairy products
across the U.S., with different combinations
of commodities sampled in different years.
Samples were analyzed for more than 290
pesticides and their metabolites.
bData for 2003 are not comparable to prior
years due to a difference in how detects were
counted. Prior to 2003, each compound
detected was counted as a separate "residue."
Beginning in 2003, parent compounds and
their metabolites were combined to report the number of
"pesticides." For example, a sample with positive detections for
endosulfan I, endosulfan II, and endosulfan sulfate would have
been counted as three residues in 2002. In 2003, this sample
would have been counted as one pesticide detection.
Data source: USDA Pesticide Data Program
Number of
residues
detected:"
no
D2
03
a 4 or more
What the Data Show
Overall, the percent of samples with no detectable
pesticide residues increased during the period from
1994 to 2002 (Exhibit 4-21). Samples with no detects
accounted for 38.5 percent of samples analyzed in
1994 and rose to 57.9 percent of samples in 2002.
Data for 2003 cannot be compared directly to the
previous years' data due to a change in the way that
detects are counted. During the same period, each of
the other categories (i.e., samples with one or more
detected residues) remained steady or declined
slightly. For example, in 1994, 9.8 percent of samples
were found to contain four or more pesticide residues;
this figure dropped to 8.2 percent in 2002. The stable
or slightly declining trend in number of detections
occurred at the same time that analytical limits of
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1
2
3
4
5
6
7
8
9
10
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
detection for these compounds have been decreasing,
allowing the instruments to pick up ever smaller
concentrations.
Exhibit 4-22. Pesticides exceeding EPA
tolerance levels in food in the U.S., 1994-2003a
Exhibit 4-22 illustrates the percentage of samples in
which at least one pesticide residue was detected at a
concentration exceeding the tolerance established by
EPA for a given pesticide-commodity pair. The
percentage of samples exceeding EPA tolerance values
increased from 0.05 percent in 1994 to 0.31 percent in
2003.
E B
en £
11 Indicator Limitations
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
"Coverage: Based on a survey of fruits, vegetables, grams, meat,
and dairy products across the U.S., with different combinations of
commodities sampled in different years. Samples were analyzed
for more than 290 pesticides and their metabolites.
Data source: USDA Pesticide Data Program
• Among the data for number of residues
detected (Exhibit 4-21), in 2003,
measurement of a parent compound and/or
any of its metabolites was counted as a
single detect whereas in previous years,
parent compounds and each of their
metabolites were counted as separate
detects. Therefore numbers from 2002 and
earlier years cannot be compared directly
with the data from 2003.
• The PDP does not sample all commodities over all years, so some gaps in coverage exist.
Differences in the percent of detections for any given pesticide class might not be due to an
increase (or decrease) in the predominance of detectable residues. Instead, these differences
might simply reflect the changing nature and identity of the commodities selected for
inclusion in any given time frame.
• The indicator measures pesticide residue related to dietary intake which does not directly
correlate to toxicological effects in humans or effects on the environment.
29 Data Sources
30 Data for this indicator were obtained from a series of annual summary reports published by the U.S.
31 Department of Agriculture's Pesticide Data Program (USDA, 1996 through 2005). These reports are all
32 available from http://www.ams.usda.gov/science/pdp/. The Food and Drug Administration also collects
33 data (not reported here) on pesticide residues in cooked food that may be a source of chemicals in human
34 diets. These data are available at http://www.cfsan.fda.gov/~dms/pesrpts.html.
35 References
36 Aspelin, A.L. 2003. Pesticide usage in the United States: trends during the 20th century. Raleigh, NC:
37 Center for Integrated Pest Management, North Carolina State University.
38
39 USDA. 2005. Pesticide Data Program: annual summary, calendar year 2003.
40
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1 USDA. 2004. Pesticide Data Program: annual summary, calendar year 2002.
2
3 USDA. 2003. Pesticide Data Program: annual summary, calendar year 2001.
4
5 USDA. 2002. Pesticide Data Program: annual summary, calendar year 2000.
6
7 USDA. 2001. Pesticide Data Program: annual summary, calendar year 1999.
8
9 USDA. 2000. Pesticide Data Program: annual summary, calendar year 1998.
10
11 USDA. 1999. Pesticide Data Program: annual summary, calendar year 1997.
12
13 USDA. 1998. Pesticide Data Program: annual summary, calendar year 1996.
14
15 USDA. 1997. Pesticide Data Program: annual summary, calendar year 1995.
16
17 USDA. 1996. Pesticide Data Program: annual summary, calendar year 1994.
18
19 U.S. EPA. 2003. Pesticides: regulating pesticides: data requirements.
20
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NDICATOR: Reported Pesticide Inciden
2 Even though pesticides play a role in protecting human health, food, and crops, they pose a risk of
3 poisoning when not used and/or stored properly. The American Association of Poison Control Centers
4 (AAPCC) collects statistics on poisonings and represents the single largest source of information on acute
5 health effects of pesticides resulting in symptoms and requiring health care (Calvert et al., 2001). The data
6 include incidents related to individual pesticides and to mixtures of products (about 8 percent of reports).
7 The data also include intentional exposures (suicide attempts and malicious use) that account for less than
8 3 percent of reports. The AAPCC uses the Toxic Exposure Surveillance System (TESS) to collect
9 information on all reported incidents.
10 This indicator is based on data from TESS published reports for the years 1986 through 2003. During this
11 period, at least 50 percent of the U.S. population was covered by Poison Control Centers (PCCs)
12 reporting to the national database. Annual reports of incidents were divided by the percent of U.S.
13 population served to estimate the total incidents nationwide, and divided by the total U.S. population to
14 develop the incidence rate. Only calls with known outcomes are reported here although this may
15 introduce some bias because the percent of all reported pesticide incidents with a known outcome
16 declined from 71 percent in 1986-1988 to just 42 percent in 2001-2003. Data are grouped into 3-year
17 periods and presented as average annual rates to facilitate identification of trends.
18 What the Data Show
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Between the periods 1986-1988 and 2001-2003, there
was an overall 40 percent decline in reported pesticide
incidents in the United States (Exhibit 4-23). The
single largest decline occurred for the category of
organophosphate (OP) insecticides, which saw a 71
percent drop in reported incidents. Part of the decline
in reported OP-related incidents may be due to the
substitution of other less toxic insecticides for some of
the OPs overtime. As reported OP-related incidents
have dropped, there has not been a corresponding
increase in incidents among the replacement products
("Other insecticides" category), which also declined
23 percent over the period. Only the "All other
pesticides" category showed an overall increase in
reports (8 percent increase).
Indicator Limitations
Misclassification of incidents may occur
when incidents reported over the phone
are not verified by laboratory tests. For
example, a child found holding a pesticide
container may not have actually been
exposed, but if a call was received by a
PCC poison specialist who determined
that the reported symptoms were
consistent with the toxicology, dose, and
Exhibit 4-23. Reported pesticide incidents per
million U.S. population by type of pesticide,
1986-2003"
c: j«
1 1100
|g 80
•I! i=
£ ! eo
Ir" 40
8. J1 20
M g^
> n
1986-1988 1989-1991 1992-1994 1995-1997 1998-2000 2001-2003
Reporting period
aThis indicator tracks pesticide
incidents reported to poison control
centers (PCCs) that report to the
AAPCC national database. The rate of
reported incidents is calculated based
on the population served by these
PCCs-approximately 50% of the
U.S. population.
Data source: American Association of
Poison Control Centers (AAPCC)
D Disinfectants
D Organophosphates
D Other insecticides
n Herbicides
D Fungicides
D Rodenticides
n All other pesticides
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1 timing of the incident, the call will be registered as an incident. About 13 percent of calls to
2 PCCs arise from health care professionals, but the majority are calls made by victims or their
3 relatives or caretakers. Although some misclassification can be expected to occur, it is
4 assumed to be non-differential among the different types of pesticides.
5 • Only calls with known outcomes are reported in this indicator. This may introduce some bias
6 because the percent of all reported pesticide incidents with a known outcome declined from
7 71 percent in 1986-1988 to just 42 percent in 2001-2003.
8 • The data collection process is standardized for PCCs, but is a passive system. Under-
9 reporting of incidents is a serious shortcoming. Studies show that medical facilities generally
10 report between 24 and 33 percent of incidents from all substances to Poison Control Centers
11 (Chafee-Bahamon et al., 1983; Harchelroad et al., 1990; Veltri et al. 1987).
12 • Data are collected by multiple poison centers with follow-up likely performed in different
13 ways.
14 Data Sources
15 This indicator is based on summary data from annual reports published by the American Association of
16 Poison Control Centers, Toxic Exposure Surveillance System (Litovitz et al., 1987 through 2002; Watson
17 et al., 2003 and 2004) (available from http://www.aapcc.org/poison 1 .htm). Annual data from these reports
18 were grouped into three-year periods, and incidence rates were calculated from the population served by
19 participating poison control centers; population figures can also be found in the annual reports. Only
20 summary data are publicly available; raw data from individual cases are considered confidential.
21 References
22 Calvert, G.M., M. Barnett, J.M. Blondell, L.N. Mehler, and W.T. Sanderson. 2001. Surveillance of
23 pesticide-related illness and injury in humans. In: Krieger, R., ed. Handbook of pesticide toxicology.
24 Second edition. San Diego, CA: Academic Press, pp. 603-641
25 Chafee-Bahamon, C., D.L. Caplan, and F.H. Lovejoy FH. 1983. Patterns in hospital's use of a regional
26 poison information center. Am. J. Public Health 73:396-400.
27 Harchelroad, F., R.F. Clark, B. Dean, and E.P. Krenzelok. 1990. Treated vs. reported toxic exposures:
28 discrepancies between a poison control center and a member hospital. Vet. Hum. Toxicol. 32:156-159.
29 Litovitz, T.L., T.G. Martin, and B. Schmitz. 1987. 1986 annual report of the American Association of
30 Poison Control Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine
31 5(5): 405-445.
32 Litovitz, T.L., B.F. Schmitz, N. Matyunas, and T.G. Martin. 1988. 1987 annual report of the American
33 Association of Poison Control Centers Toxic Exposure Surveillance System. American Journal of
34 Emergency Medicine 6(5): 479-515.
35 Litovitz, T.L., B.F. Schmitz, and K.C. Holm. 1989. 1988 annual report of the American Association of
36 Poison Control Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine
37 7(5): 495-545.
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1 Litovitz, T.L., B.F. Schmitz, and K.M. Bailey. 1990. 1989 annual report of the American Association of
2 Poison Control Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine
3 8(5): 394-442.
4 Litovitz, T.L., K.M. Bailey, B.F. Schmitz, K.C. Holm, and W. Klein-Schwartz. 1991. 1990 annual report
5 of the American Association of Poison Control Centers Toxic Exposure Surveillance System. American
6 Journal of Emergency Medicine 9(5): 461-509.
7 Litovitz, T.L., K.C. Holm, K.M. Bailey, and B.F. Schmitz. 1992. 1991 annual report of the American
8 Association of Poison Control Centers Toxic Exposure Surveillance System. American Journal of
9 Emergency Medicine 10(5): 452-504.
10 Litovitz, T.L., K.C. Holm, C. Clancy, B.F. Schmitz, L.R. Clark, and G.M. Oderda. 1993. 1992 annual
11 report of the American Association of Poison Control Centers Toxic Exposure Surveillance System.
12 American Journal of Emergency Medicine 11(5): 494-555.
13 Litovitz, T.L., L.R. Clark, and R.A Soloway. 1994. 1993 annual report of the American Association of
14 Poison Control Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine
15 12(5): 546-584.
16 Litovitz, T.L., L. Felberg, RA Soloway, M. Ford, and R Geller. 1995. 1994 annual report of the
17 American Association of Poison Control Centers Toxic Exposure Surveillance System. American Journal
18 of Emergency Medicine 13(5): 551-597.
19 Litovitz, T.L., L. Felberg, W. Klein-Schwartz, and S. White. 1996. 1995 annual report of the American
20 Association of Poison Control Centers Toxic Exposure Surveillance System. American Journal of
21 Emergency Medicine 14(5): 487-537.
22 Litovitz, T.L., M. Smilkstein, L. Felberg, W. Klein-Schwartz, R. Berlin, and J.L. Morgan. 1997. 1996
23 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance
24 System. American Journal of Emergency Medicine 15(5): 447-500.
25 Litovitz, T.L., W. Klein-Schwartz, K.S. Dyer, M. Shannon, S. Lee, and M. Powers. 1998. 1997 annual
26 report of the American Association of Poison Control Centers Toxic Exposure Surveillance System.
27 American Journal of Emergency Medicine 16(5): 443-497.
28 Litovitz, T.L., W. Klein-Schwartz, E.M. Caravati, J. Youniss, B. Crouch, and S. Lee. 1999. 1998 annual
29 report of the American Association of Poison Control Centers Toxic Exposure Surveillance System.
30 American Journal of Emergency Medicine 17(5): 435-487.
31 Litovitz, T.L., W. Klein-Schwartz, S. White, D.J. Cobaugh, J. Youniss, A. Drab, and B.E. Benson. 2000.
32 1999 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance
33 System. American Journal of Emergency Medicine 18(5): 517-571.
34 Litovitz, T.L., W. Klein-Schwartz, S. White, D.J. Cobaugh, J. Youniss, J.C. Omslaer, A. Drab, and B.E.
35 Benson. 2001. 2000 annual report of the American Association of Poison Control Centers Toxic
36 Exposure Surveillance System. American Journal of Emergency Medicine 19(5): 337-395.
37
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1 Litovitz, T.L., W. Klein-Schwartz, G.C. Rodgers, Jr, D.J. Cobaugh, J. Youniss, J.C. Omslaer, M.E. May,
2 A.D. Woolf, and B.E. Benson. 2002. 2001 annual report of the American Association of Poison Control
3 Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine 20(5): 391-452.
4
5 Veltri, J.C., N.E. McElwee, and M.C. Schumacher. 1987. Interpretation and uses of data collected in
6 poison control centers in the United States. Med. Toxicol. 2:389-397.
7 Watson, W.A., T.L. Litovitz, G.C. Rodgers, Jr, W. Klein-Schwartz, J. Youniss, S.R. Rose, D. Borys, and
8 M.E. May. 2003. 2002 annual report of the American Association of Poison Control Centers Toxic
9 Exposure Surveillance System. American Journal of Emergency Medicine 21(5): 353-421.
10
11 Watson, W.A., T.L. Litovitz, W. Klein-Schwartz, G.C. Rodgers, Jr, J. Youniss, N. Reid, W.G. Rouse,
12 R.S. Rembert, and D. Borys. 2004. 2003 annual report of the American Association of Poison Control
13 Centers Toxic Exposure Surveillance System. American Journal of Emergency Medicine 22(5): 335-404.
14
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1 4.5.3 Discussion
2 What These Indicators Say about Trends in Chemicals Used on the Land
3 and Their Effects on Human Health and the Environment
4 These indicators provide information on aspects of chemical use and effects. Data are presented on the
5 amounts and types of chemical usage for two large sectors of the U.S. economy-agriculture and
6 manufacturing. The disposition of pesticides in food and the number of reported pesticide incidents are
7 examined. Two indicators describe stressors to the environment from chemical usage.
8 The amount of chemicals deliberately applied to agricultural land as commercial fertilizer has increased
9 steadily over the last 40 years (Agricultural Fertilizer indicator, p. 4-50). Per acre total fertilizer use has
10 nearly tripled since 1960 with peak usage occurring in 1994. Nitrogen use per acre has more than
11 quadrupled over the same period. While fertilizers themselves are not inherently harmful, when applied
12 improperly or in quantities above the level taken up by crops, streamside vegetation, or soil biota, they
13 have the potential to contaminate groundwater and surface water in agricultural watersheds and estuaries.
14 Fertilizer usage in 2000, for major crops, appears concentrated in the states surrounding the Mississippi
15 River.
16 The Toxic Release Inventory (TRI) data (Toxic Chemicals in Wastes indicator, p. 4-54) show a small but
17 steady decline in the quantities of TRI chemicals released to all media between 1998 and 2003, with the
18 exception of offsite releases, which increased slightly. For purposes of this indicator, TRI chemicals
19 represent the most toxic chemicals associated with production-related wastes.
20 Residues of potentially harmful substances used in food production, such as some pesticides, are assessed
21 under food protection programs. While national-level indicators on the use and application of pesticides
22 and pesticide loads in soil are lacking, the Pesticide Residues in Food indicator (p. 4-58) is an indirect
23 measure of ambient conditions, providing insight into potential exposures from the most widely used
24 pesticide products on the market. The indicator shows that in the time period where data are comparable,
25 between 40 and 60 percent of the food commodities tested had one or more pesticide residues detected. It
26 is important to note that current available technology used in the U.S. Department of Agriculture
27 Pesticide Data Program (POP) sampling provides the ability to detect pesticide residues at concentrations
28 that are orders of magnitude lower that those determined to potentially have human health effects.
29 Therefore, the number of pesticide detections that exceed federally established tolerance levels is perhaps
30 more relevant. Results over the years suggest less than 1 percent of commodities tested were above
31 tolerance levels.
32 Similarly, the Pesticide Incidents indicator (p. 4-61) provides information on the potential for human
33 exposure to toxic substances through misuse. Reported incidents of pesticide exposure, which represent
34 accidental exposure to a pesticide that is readily available to the public, declined between 1986 and 2003.
35 The largest decline has occurred in organophosphate compounds, a group of insecticides that are acutely
36 toxic to humans (and other vertebrates), but do not accumulate in the environment, unlike other toxic
37 materials or compounds containing chromium, arsenic, heavy metals, etc.
38 Limitations, Gaps, and Challenges
39 While chemicals in soil or on plants may be an initial pathway into the environment, it is the movement
40 and concentration of chemicals through the food chain that are often of greatest concern, as well as
41 exposures from other media such as contaminated water or air. The indicators provide information on a
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1 relatively small universe of toxic chemicals and only limited information on the potential exposures
2 humans may experience as a consequence of chemical use.
3 Fertilizer use in agriculture has been identified as one of the principal uses of chemicals responsible for
4 nutrient loading into non-targeted water bodies and for nonpoint source loading of nutrients within
5 agricultural watersheds.26 Actual fertilizer use data are not available nationally. The Agricultural Fertilizer
6 indicator (p. 4-50) is supported by sales data that do not consider mitigating factors (e.g., slow-release
7 formulations) or agricultural practices that reduce runoff. The cost of fertilizer accounts for a relatively
8 high percentage of agricultural costs, so it is generally assumed that purchased products eventually are
9 applied in agricultural operations. Agricultural sources of fertilizer, however, are only estimated to be 85
10 percent of all sources, with the remaining being primarily professional lawn care, consumer retail, and
11 golf courses. The usage patterns associated with these nonagricultural sources are unknown. Additionally,
12 the urban and suburban watersheds, where these non-tracked uses occur are also locations where nutrient
13 runoff may result from other sources such as turf runoff, septic systems, and sewage treatment plants.
14 The indicators do not provide information related to the land application of sludges27 that may contain
15 toxic metals and other persistent bioaccumulative substances. Sludges may be applied as fertilizer on
16 agricultural or forest land in accordance with EPA requirements, but the implications for wildlife, aquatic
17 organisms, and movement through the food chain are unknown. Additionally, the indicators reported
18 provide only limited information on the potential exposures that target organisms other than humans may
19 experience as a consequence of chemical use.
20 TRI data include information on a range of chemical categories such as arsenic, cyanide, dioxin, lead,
21 mercury, and nitrate compounds, but do not reflect a comprehensive total of toxic releases nationwide.
22 They do not include all toxic chemicals with the potential to affect human health and the environment, nor
23 do they include all sources of potential releases. Facilities report release and other waste management data
24 using various techniques which include estimations based on emission factors, mass balancing
25 approaches, engineering calculations, and actual monitoring. Estimation techniques and factors
26 considered may vary widely, making it difficult to ensure the accuracy of reporting. TRI data only
27 represent a portion of the chemical life cycle (e.g., wastes as a result of production) and do not take into
28 account amounts of chemicals incorporated into industrial and/or consumer products which also have the
29 potential to affect the environment and human health when they are used, discarded, or recycled.
30 There is no existing reporting system that provides information on the volume, distribution, and extent of
31 pesticide use in the United States. Estimates are developed based on information available through a
32 variety of reports from multiple governmental and non-governmental entities on pesticide sales, crop
33 profiles, and expert surveys. The Pesticide Residues in Food indicator (p. 4-58) provides information on
34 one aspect of the potential for human exposure from pesticides (dietary intake from the commercial food
35 supply), but does not provide a complete picture of all the ways in which humans can be exposed to
36 pesticides, which include contaminated drinking water, pesticide drift, and dermal contact.
37
26 Howarth, R.W., D. Walker, and A. Sharpley. 2002. Sources of nitrogen pollution to coastal waters of the United
States. Estuaries 25:656-676.
27 Sludges are the nutrient-rich organic materials resulting from sewage and wastewater treatment processes.
Sludges contain many of the nutrients required for improved plant growth (N, P, and K) and other organic matter
that can improve overall soil condition and increase productivity.
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1 4.6 WHAT ARE THE TRENDS IN CONTAMINATED LAND AND THEIR EFFECTS
2 ON HUMAN HEALTH AND THE ENVIRONMENT?
3 4.6.1 Introduction
4 There are many settings for contaminated lands, ranging from abandoned buildings in inner cities to large
5 areas contaminated with toxics from past industrial or mining activities. Contaminated lands include sites
6 contaminated by improper handling or disposal of toxic and hazardous materials and wastes, sites where
7 toxic materials may have been deposited as a result of wind or flood, and sites where improper handling
8 or accidents resulted in release of toxic or hazardous materials that are not wastes.
9 Land contamination can result from a variety of intended, accidental, or naturally occurring activities and
10 events such as manufacturing, mineral extraction, abandonment of mines, national defense, waste
11 disposal, accidental spills, illegal dumping, leaking underground storage tanks, hurricanes, or floods. Sites
12 are categorized in a variety of ways, often based on the level and type of contamination and the
13 regulations under which they are monitored and cleaned up. Text Box 4.1 provides an overview of the
14 common types of contaminated sites. With the exception of accidental spills and contamination that result
15 from naturally occurring and other unanticipated events, most land contamination is the result of
16 historical activities that are no longer practiced. Hazardous material and waste management and disposal
17 are now highly regulated.
18 Contaminated soils can leach toxic chemicals into nearby ground or surface waters, where these materials
19 can be taken up by plants and animals, contaminate a human drinking water supply, or volatize and
20 contaminate the indoor air in overlying buildings. In dry areas, contamination in soil can be further
21 distributed through wind-borne dusts. Once soil contamination migrates to waterways, it may also
22 accumulate in sediments, which can be very difficult to remediate and may affect local ecosystems and
23 human health. Humans can be harmed by contact with toxic and hazardous materials on a contaminated
24 site via contact with land, air, water, and groundwater. When contaminated lands are not properly
25 managed, humans and wildlife can come into contact with contaminants through inhalation, ingestion, or
26 direct contact. The risks of human exposure are site-specific and difficult to generalize at the national
27 level. Potential effects may be acute or chronic.
28 Some contaminated sites pose little risk to human health and the environment, because the level of
29 contamination is low and the chance of exposure to toxic or hazardous contaminants is also low. Other
30 contaminated sites are of greater concern because of the chemicals that may be present and their
31 propensity to persist in or move through the environment, exposing humans or the environment to
32 hazards. These sites must be carefully managed through containment or cleanup to prevent hazardous
33 materials from causing harm to humans, wildlife, or ecological systems, both on- and off-site.
34
35
36
37
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Text Box 4.1: Categorizing Contaminated Lands
Superfund National Priority List (NPL) Sites - The Superfund NPL sites are seriously-contaminated and include
industrial facilities, waste management sites, mining and sediment sites, and federal facilities such as abandoned mines;
nuclear, biological, chemical, and traditional weapons productions plants; and military base industrial sites (e.g., used for
aircraft and naval ship maintenance).
Resource Conservation and Recovery Act Cleanup Baseline Facilities - The RCRA Cleanup Baseline is a priority
subset of a broader universe of facilities that are subject to cleanup under RCRA due to past or current treatment,
storage, or disposal of hazardous wastes and have historical releases of contamination.
Underground Storage Tanks/ Leaking Underground Storage Tanks - Businesses, industrial operations, gas stations,
and various institutions store petroleum and hazardous substances in large underground storage tanks that may fail due
to faulty materials, installation, operating procedures, or maintenance systems causing contamination of soil and ground
water,
Accidental Spill Sites - Each year, thousands of oil, gas, and chemical spills occur on land and in water from a variety of
types of incidents, including transportation (e.g., rail, barges, tankers, pipeline) and facility releases.
Sites Contaminated by Natural Disasters or Terrorist Activities - Disasters of any sort, naturally occurring or caused
by humans, have the potential to create contaminated lands and cause problems at existing contaminated sites.
Land Contaminated with Radioactive and Other Hazardous Materials - Many sites spanning a large area of land in
the United States are contaminated with radioactive and other hazardous materials as a result of activities associated with
nuclear weapons production, testing, and research.
Brownfields - Brownfields are real property, the expansion, redevelopment, or reuse of which may be complicated by the
presence or potential presence of a hazardous substance, pollutant, or contaminant. Brownfields are often found in and
around economically depressed neighborhoods.
Military Bases and Defense Sites - Some of the millions of acres of land used by the Department of Defense are
contaminated from releases of hazardous substances and pollutants; discarded munitions, munitions constituents, and
unexploded ordnance; and building demolition and debris.
Low Level Area-wide Contamination - Some soil contamination problems involve low-to-moderate levels of
contamination that encompass large geographic areas ranging in size from several hundred acres to many square miles.
Low-level, area-wide contamination can occur from emissions related to past industrial operations (e.g., smelters),
widespread agricultural pesticide applications, combustion of gasoline, and deterioration of lead-based paint.
Past Waste Management Sites and Illegal Dumping Sites - Prior to the 1970s, solid waste was typically placed in
unlined landfills that were not adequately designed to prevent adverse environmental impacts to ground water or surface
water. Separately, illegal dumping of materials such as construction waste, abandoned automobiles, appliances,
household waste, and medical waste, has occurred for decades and still occurs because of convenience and the cost of
legal disposal.
Abandoned and Inactive Mine Lands - Abandoned and inactive mines have not been properly cleaned up, and may
have features ranging from exploration holes to full-blown, large-scale mine openings, pits, waste dumps, and processing
facilities.
1
2
3 Nationally, there are thousands of contaminated sites of varying size and significance. Many sites,
4 particularly the largest and most severely contaminated, are tracked at the national level, but many others
5 are tracked only at state or local levels. The number and status of contaminated sites changes frequently
6 as sites are newly contaminated (e.g., via spills or hurricanes), discovered, documented, and cleaned up.
7 4.6.2 ROE Indicators
8 The ROE indicators for this question focus on the trends in reducing potential threats to human health
9 associated with site contamination at some lands contaminated by a variety of industrial and other
10 activities and from current and past waste management activities (Table 4.6.1). The indicators address
11 sites on the Superfund National Priorities List (NPL) and facilities on the Resource Conservation and
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1 Recovery Act (RCRA) Cleanup Baseline where human contact with contamination and migration of
2 contaminated groundwater has been documented to be within acceptable established health-based levels.
3 Trends in the spread of contaminated groundwater and potential human contact with contaminants in
4 excess of health-based standards are assessed through site-specific monitoring and modeling data
5 collected by site personnel. Site data and conditions are generally reviewed and confirmed by federal
6 and/or state program managers annually or more frequently if site conditions warrant.
7 Table 4.6.1. ROE Indicators of Trends in Contaminated Land and Their Effects on Human Health
8 and the Environment
NATIONAL INDICATORS
High-Priority Cleanup Sites with No Human Contact to Contamination
in Excess of Health-Based Standards
High-Priority Cleanup Sites Where Contaminated Groundwater Is Not
Continuing to Spread Above Levels of Concern
LOCATION
4.5.2 -p. 4-70
4.5.2 -p. 4-73
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INDICATOR: High-Priority Cleanup Sites with No Human Contact to
Contamination in Excess of Health-Based Standards
3 The EPA Superfund and Resource Conservation and Recovery Act (RCRA) Programs conduct a number
4 of activities to address the nation's most severely-contaminated lands. The Programs investigate and
5 collect data on potentially-contaminated sites to determine whether they are contaminated and require
6 cleanup. When a potentially-hazardous waste site is reported to EPA, trained inspectors determine
7 whether the site presents a hazard to human health and the environment. Sites that pose the greatest threat
8 are placed on the Superfund National Priorities List (NPL) or RCRA Cleanup Baseline. For RCRA,
9 "sites" are more commonly referred to as RCRA Corrective Action Facilities.
10 One of the priorities for both the NPL and RCRA Cleanup Baseline sites is safeguarding against human
11 contact with site contamination. EPA and state officials determine whether humans are in contact with
12 site contamination and if interim actions are needed to reduce or eliminate all current human contact in
13 excess of health-based standards. Such activities may include removing and/or isolating contaminated
14 media, providing alternative water supplies, and restricting access or other land use controls. Contact at
15 levels below the standards is considered protective. Although these standards may vary from state to state,
16 EPA believes that they fall within an acceptable range for gauging whether human health is protected
17 (U.S. EPA, 2005c). Determinations of human contact at levels of concern are based on site-specific
18 characterization information and monitoring data (usually many analytical samples) pertaining to relevant
19 environmental media (e.g., soil, indoor air, outdoor air, groundwater, and surface water), current human
20 activity patterns, and actions taken to prevent human contact. All potential contact routes are assessed,
21 including inhalation, direct contact, or ingestion of the contaminated media or food affected by
22 contaminated media (U.S. EPA, 1999, 2005c).
23 This indicator describes the numbers of NPL and RCRA Cleanup Baseline sites for which government
24 officials have determined that humans are not in contact with contamination in excess of health-based
25 standards, are reasonably expected to be in contact with contamination in excess of health-based
26 standards, or insufficient information exists to make a finding of contact with contamination in excess of
27 health-based standards. The intention of the indicator is not to capture an "action" or "administrative
28 determination" on the part of EPA, but to characterize environmental conditions relevant to the risk to
29 human health from contaminants at RCRA Cleanup Baseline and NPL sites.
30 What the Data Show
31 There are 1,714 sites on the RCRA Cleanup Baseline (U.S. EPA, 2005b). Of these, the percentage of sites
32 where human contact to contamination in excess of health-based standards has been shown not to occur
33 increased from 37 percent (642 sites) in fiscal year (FY) 2000 to 96 percent (1,649 sites) in FY 2005
34 (Exhibit 4-24, panel A). This increase represents a combination of sites where mitigation has prevented
35 contact with contaminants and sites where the availability of sufficient data show that contact with
36 contaminated media was not a problem, regardless of mitigation. The percentage of sites where officials
37 had reasonable expectations that humans were in contact with contamination in excess of health-based
38 standards has decreased from 13 percent (225 sites) in FY 2000 to just over 1 percent (20 sites) in FY
39 2005. These sites and the 45 remaining sites in 2005 for which there is insufficient information to make a
40 determination include very complex sites where the appropriate data have yet to be collected due to high
41 costs or technical difficulties.
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1 As of October 2005, there were 1,547 sites on the NPL
2 that were categorized as "Final" or "Deleted" (U.S.
3 EPA, 2005d, 2005e). Given that the number of sites on
4 the NPL changes each year, the percentages shown in
5 this indicator are based on each year's total number of
6 Final and Deleted NPL sites with determinations as to
7 whether the site presents a hazard to human health and
8 the environment. NPL sites where human contact to
9 contamination in excess of health-based standards has
10 been shown not to occur remained relatively constant
11 as a percentage of the total: 79 percent ( 1 , 1 85 of 1 ,498
12 sites) in 2002 and 80 percent (1,235 of 1,547 sites) in
13 2005 (Exhibit 4-24, panel B). As of the end of FY
14 2005, officials determined that there are reasonable
15 expectations that humans are in contact with
16 contamination in excess of health-based standards at
17 9.6 percent (148 out of 1,547) of the NPL sites. This is
18 an increase from 2002, when the percentage was 8.1
19 percent (121 out of 1,498). In 2005, there was
20 insufficient information to confirm whether humans
2 1 were in contact with contamination in excess of
22 health-based standards at 10.6 percent (164) of the
23 sites.
24 Indicator Limitations
25 • The NPL does not represent all of the
26 contaminated or potentially-contaminated
27 sites listed in the Comprehensive
28 Environmental Response, Compensation,
29 and Liability Information System
30 (CERCLIS) database that contains
3 1 information on thousands of hazardous
32 waste sites, potential hazardous waste
33 sites, and remedial activities across the
34 nation.
35 • The indicator results are presented for the a
36 1,714 RCRA Cleanup Baseline sites, and
; r j
37 not the entire group of approximately
38 6,500 hazardous waste management sites
3 9 that fall under the federal RCRA
40 Corrective Action Program.
41 • The indicator does not typically make
42 measurements of exposure biomarkers
Exhibit
4-24. Status of human contact with
contamination at high-priority cleanup sites in
the U.S
., fiscal years 2000-2005
A. RCRA Cleanup Baseline sites
2,000
1,500
1
o3 1 '"00
.a
E
•z.
500
1,714 1,714 1,714
847
225
642
(37%
of
total)
703
188
823
(48%
of
total)
550
146
1,018
(59%
of
total)
2000 2001 2002
1,714
si
1,246
(73%
Of
total)
2003
1,714 1,714
212
\62
Ut.
1,440
(84%
Of
total)
1*
1,649
(96%
of
total)
2004 2005
Fiscal year
n Insufficient
data3
n Reasonable
expectation
that contact
is occurring
above
health-based
standards
D No human
contact with
contamination
in excess of
health-based
standards
B. superfimd National
Priorities List sites
2,000
1,500
tn
'w
% 1,000
E
500
rt
1,498
192
121
1,185
(79%
of
total)
2002
1r--4 Q
,518
182
119
1,217
(80%
of
total)
2003
i ,o
-------
1 vary from state to state but fall within a range determined to be acceptable to EPA (U.S. EPA,
2 2005a, 2005c).
3 • The indicator is based on certification by a responsible official that the criteria necessary to
4 designate a site as having/not having human contact to contamination in excess of health-
5 based standards have been met (U.S. EPA, 1999, 2005a, 2005c). The trend in the number of
6 sites may be underestimated to the extent that certification lags behind the potential human
7 contact with contamination or certification is delayed due to insufficient or outdated
8 information.
9 • This approach may not take into account certain risks (e.g., endocrine disrupters) where
10 specific risk-levels may not have been established. Some new sites (e.g., those created with
11 the "reportable quantity" spill response program) as well as other known sites (e.g., spills) are
12 not included in this indicator.
13 Data Sources
14 Data for this indicator were provided by EPA's Office of Solid Waste and Emergency Response
15 (OSWER). A list showing the current status of every RCRA baseline site is published online (U.S. EPA,
16 2005b). A summary of the status of Superfund NPL sites is available online for the most recent fiscal year
17 (U.S. EPA, 2005d); information on the current status of any individual NPL site can be queried using
18 EPA's CERCLIS database (U.S. EPA, 2006) (http ://cfpub .epa.gov/supercpad/cursites/srchsites .cfm).
19 Data for previous years are not publicly accessible, however, and must be requested from OSWER.
20 References
21 U.S. EPA. 1999. Interim-final guidance for RCRA corrective action environmental indicators. Accessed
22 December 15. 2005.
23 U.S. EPA. 2005a. Draft Superfund environmental indicators guidance manual: long-term human health
24 revisions. Accessed December 13, 2005.
25 U.S. EPA. 2005b. Facilities on the RCRA GPRA cleanup baseline. Accessed October 18, 2005.
26
27 U.S. EPA. 2005c. Frequently asked questions—human exposure under control (HE) and migration of
28 contaminated ground water under control (GM) environmental indicators. Accessed December 13, 2005.
29
30 U.S. EPA. 2005d. Human exposure under control. Accessed December 13, 2005.
31
32 U.S. EPA. 2005e. NPL site listing process. Accessed December 13, 2005.
33
34 U.S. EPA. 2006. CERCLIS database. Accessed September 14, 2006.
35
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INDICATOR: High-Priority Cleanup Sites Where Contaminated Groundwater Is
Not Continuing to Spread Above Levels of Concern
3 The EPA Superfund and Resource Conservation and Recovery Act (RCRA) Programs conduct a number
4 of activities to address the nation's most severely-contaminated lands. The Programs investigate and
5 collect data on potentially-contaminated sites to determine whether they are contaminated and require
6 cleanup. When a potentially-hazardous waste site is reported to EPA, trained inspectors determine
7 whether the site presents a hazard to human health and the environment. Sites that pose the greatest threat
8 are placed on the National Priorities List (NPL) or RCRA Cleanup Baseline.
9 One of the priorities for both the NPL and RCRA Cleanup Baseline sites is preventing the continued
10 spread of contaminated groundwater, often referred to as "plumes" of contaminated groundwater.
11 Protecting the groundwater is especially important in those areas where groundwater is the primary source
12 for drinking water and irrigation, or a potential source for future water supplies.
13 EPA and state officials determine that the migration of contaminated groundwater is not continuing above
14 levels of concern when ongoing monitoring shows that the contaminant plume is not expanding or
15 negatively impacting surface waters (U.S. EPA, 1999). Preventing further migration of contaminated
16 groundwater may result from an action taken, such as installation of a "pump and treat" or subsurface
17 barrier system, or because of natural attenuation of the contaminants. A determination of whether
18 migration has been prevented is based on monitoring data (usually hundreds of analytical samples)
19 collected from groundwater wells located within and surrounding the spatial extent of the groundwater
20 plume (U.S. EPA, 1999, 2005c).
21 This indicator describes the percentage of NPL and RCRA Cleanup Baseline sites where government
22 officials have determined that groundwater is not continuing to spread above levels of concern (e.g., that
23 exceed the appropriate drinking water standards). This indicator covers both final and deleted NPL sites,
24 and all 1,714 RCRA Cleanup Baseline sites. The percentage of sites where groundwater contamination
25 continues to spread is also noted, as well as the number of sites where there are insufficient data to make a
26 finding. The intention of the indicator is not to capture an "action" or "administrative determination" on
27 the part of EPA, but to convey the underlying pressure on the environment and potential for human health
28 effects resulting from contaminated groundwater.
29 What the Data Show
30 Of the 1,714 high-priority RCRA Cleanup Baseline sites, the percentage of sites where contaminated
31 groundwater has been determined not to be spreading above levels of concern increased from 32 percent
32 (554 sites) in FY 2000 to 78 percent (1,342 sites) in FY2005 (Exhibit 4-25, panel A). This increase
33 represents a combination of sites where mitigation has halted the spread of contaminated groundwater,
34 and sites where sufficient data have been collected to show that contaminated groundwater migration was
35 not continuing, regardless of mitigation activities. The percentage of sites where officials have determined
36 that contaminated groundwater was spreading above levels of concern decreased from 18 percent (306
37 sites) in FY 2000 to less than 7 percent (115 sites) in FY 2005. These sites, and the remaining 257 sites
38 for which there are still insufficient data to make a determination at the end of FY 2005, tend to be very
39 complex sites where the appropriate data have yet to be collected due to high costs or technical
40 difficulties.
41 Groundwater has not been an issue at all Superfund NPL sites. Of those Final and Deleted NPL sites
42 where groundwater contamination is present, the percentage where contaminated groundwater has been
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4-73
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Exhibit 4-25. Status of contaminated ground
water spreading at high-priority cleanup sites in
the U.S., fiscal years 2000-2005
2,000
j-i-
_-*
A. RCRA Cleanup Baseline sites
1,714 1,714 1,714 1,714 1,714 1,714
854
306
554
(32%
of
total)
734
271
709
(41%
of
total)
610
231
873
(51%
of
total)
475
191
1,048
(61%
of
total)
358
157
1,199
(70%
of
total)
257
115
1,342
(78%
of
total)
2000 2001 2002 2003 2004 2005
Fiscal year
n Non-ground
water sites
D Insufficient
dataa
a Contaminated
ground water
Is spreading
above levels
of concern
D Contaminated
ground water
Is not
spreading
above levels
of concern
B. Superfund National
Priorities List sites"
1,500
w
2 1,000
£
500
n
1,498
213
230
290
765
(60%
of
total)
1,518 1,529
214
230
260
814
(62%
of
total)
181
211
249
888
(66%
of
total)
1,547
153
231
226
937
(67%
of
total)
2002 2003 2004 2005
Fiscal year
"For RCRA Cleanup Baseline sites, "insufficient data" includes
sites officially classified as "insufficient data" or "no status." For
Superfund NPL sites, this category includes sites officially
classified as "insufficient data" or "no data."
bFor Superfund NPL sites, the percentage in the "not spreading"
category is based on the total number of sites with contaminated
ground water (does not include "non-ground water" sites).
Data source: U.S. EPA, Office of Solid Waste and Emergency
Response (OSWER)
demonstrated not to be spreading above levels of
concern increased from 60 percent (765 sites) in FY
2002 to 67 percent (937 sites) in FY 2005 (Exhibit 4-
25, panel B). As of October 2005, contaminated
groundwater was confirmed to be spreading above
levels of concern at 16 percent (226) of these NPL
sites, while the remaining 17 percent (231 sites) had
insufficient data to confirm whether contaminated
groundwater is spreading above levels of concern.
These percentages do not include the 153 NPL sites
classified as "non-groundwater" sites.
Indicator Limitations
• The NPL does not represent all of the
contaminated or potentially contaminated
sites listed in the Comprehensive
Environmental Response, Compensation,
and Liability Information System
(CERCLIS) database that contains
information on thousands of hazardous
waste sites, potential hazardous waste
sites, and remedial activities across the
nation. Within the NPL sites, data are not
available or insufficient to assess a
number of sites.
• The indicator covers the 1,714 RCRA
Cleanup Baseline sites, and not the entire
group of 6,500 hazardous waste
management sites that fall under the
federal RCRA Corrective Action
Program.
• The extent to which people have been
affected, or could be affected, by the
contaminated groundwater at NPL or
RCRA Cleanup Baseline sites is not
considered in this indicator, but is
addressed in human-contamination
contact indicator (High Priority Cleanup
Sites with No Human Contact to
Contamination in Excess of Health-Based
Standards).
• The indicator does not address
groundwater contaminated at other types
of sites, such as sites with leaking
underground storage tanks and other sites
being addressed solely by state cleanup
programs.
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4-74
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1 • Concentrations of toxic and hazardous contaminants in groundwater that must not be
2 exceeded to designate a site as under control vary somewhat from state to state, but fall
3 within a range determined to be acceptable to EPA (U.S. EPA 2005a, 2005c).
4 • This indicator is based on the certification by a responsible official that the criteria necessary
5 to designate whether contaminated groundwater is continuing to spread above levels of
6 concern have been met (U.S. EPA, 1999, 2005a, 2005c). Trends in the number of sites where
7 the spread of contaminated groundwater has been shown to occur above levels of concern
8 may be underestimated to the extent that certification lags behind the migration of
9 contaminated groundwater or certification is delayed due to insufficient or outdated
10 information.
11 Data Sources
12 Data for this indicator were provided by EPA's Office of Solid Waste and Emergency Response
13 (OSWER). A list showing the current status of every RCRA baseline site is published online (U.S. EPA,
14 2005b). A summary of the status of Superfund NPL sites is available online for the most recent fiscal year
15 (U.S. EPA, 2005d); information on the current status of any individual NPL site can be queried using
16 EPA's CERCLIS database (U.S. EPA, 2006) (http://cfpub.epa.gov/supercpad/cursites/srchsites.cfm).
17 Data for previous years are not publicly accessible, however, and must be requested from OSWER.
18 References
19 U.S. EPA. 1999. Interim-final guidance for RCRA corrective action environmental indicators. Accessed
20 December 13. 2005.
21 U.S. EPA. 2005a. Draft Superfund environmental indicators guidance manual: long-term human health
22 revisions. Accessed December 13, 2005.
23 U.S. EPA. 2005b. Facilities on the RCRA GPRA cleanup baseline. Accessed October 18, 2005.
24
25 U.S. EPA. 2005c. Frequently asked questions—human exposure under control (HE) and migration of
26 contaminated groundwater under control (GM) environmental indicators. Accessed December 13, 2005.
27
28 U.S. EPA. 2005d. Migration of contaminated ground water under control. Accessed December 13, 2005.
29
30 U.S. EPA. 2006. CERCLIS database. Accessed September 14, 2006.
31
32
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1 4.6.3 Discussion
2 What These Indicators Say About Trends in Contaminated Lands and Their
3 Effects on Human Health and the Environment
4 The indicators provide insights into trends in protecting humans and groundwater from the nation's most
5 contaminated lands. In 2005, almost all (more than 95 percent) of the RCRA facilities showed that human
6 contact to contamination in excess of health-based standards was being prevented, while groundwater was
7 not spreading above levels of concern at slightly more than 75 percent of the facilities. Similarly in 2005,
8 the Superfund NPL sites showed that contact of humans to contamination in excess of health-based
9 standards has been prevented at more than 80 percent of the sites, and groundwater has been prevented
10 from spreading above levels of concern at more than 60 percent of the sites with groundwater
11 contamination.
12 Limitations, Gaps, and Challenges
13 The two ROE indicators are limited in their ability to address the question. Currently, there is no single
14 information source that tracks the extent of contaminated land nationwide. A substantial amount is known
15 about thousands of the most contaminated sites on the Superfund National Priorities List (NPL) and
16 facilities on the RCRA Cleanup Baseline, which have been the focus of in-depth studies and resource-
17 intensive cleanup operations. Although these facilities represent some of the most seriously contaminated
18 sites in the country, they do not reflect the full universe of contaminated sites or even the full universe of
19 seriously contaminated sites. EPA would like to have information on other sites that require extensive
20 cleanup including those contaminated with radioactive materials from historical nuclear weapons
21 production; sites with leaking underground storage tanks; smaller accidental spill sites; and other cleanup
22 sites managed by a variety of local, state, and federal authorities. Collectively, these contaminated sites
23 outnumber the NPL sites and RCRA Cleanup Baseline facilities.
24 The Agency would also like to have information on the actual acreage and types of contamination from
25 all sources nationally. Even where national data on contaminated sites are available, the affected area and
26 the types and severity of contamination vary widely from site to site, making accurate trend analysis,
27 aggregation, and generalization difficult or impossible. There is no comprehensive data source to
28 determine the extent of these lands, populations that may be affected, and the potential for contamination
29 to have harmful human health or ecological effects. Furthermore, EPA is interested in knowing how much
30 previously contaminated land has been returned to productive uses. Data associated with the use of
31 previously contaminated land could contribute to addressing both the question of trends and effects of
32 contaminated land and the question of trends and effects of land use.
33 Current data gaps around contaminated lands stem from a variety of factors and challenges, including the
34 multi-jurisdictional responsibilities for identifying, managing, and cleaning up contaminated lands; a
35 focus in most contaminated lands data sets on measures of regulatory compliance and associated
36 activities; high costs to identify, inventory, study, and cleanup large complicated sites; and complexity in
37 the effects of contaminated lands on human health and the environment, including unique site
38 characteristics and inability to generalize information over large geographic areas.
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CHAPTER 5
HUMAN HEALTH
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HEALTH CHAPTER CONTENTS
5.1 INTRODUCTION 5-5
5.1.1 The Environmental Public Health Paradigm 5-6
Establishing Linkages Between Environmental Contaminants and Health Outcomes....5-7
5.1.2 Overview of the Data 5-8
5.1.3 Organization of This Chapter 5-9
5.2 WHAT ARE THE TRENDS IN HEALTH STATUS IN THE UNITED STATES? 5-11
5.2.1 Introduction 5-11
5.2.2 Indicators 5-12
INDICATOR: General Mortality 5-13
INDICATOR: Life Expectancy at Birth 5-17
INDICATOR: Infant Mortality 5-19
5.2.3 Discussion 5-22
What These Indicators Say About Trends in U.S. Health Status 5-22
Limitations, Gaps, and Challenges 5-24
5.3 WHAT ARE THE TRENDS IN HUMAN DISEASE AND CONDITIONS FOR WHICH
ENVIRONMENTAL CONTAMINANTS MAY BE A RISK FACTOR, INCLUDING
ACROSS POPULATION SUBGROUPS AND GEOGRAPHIC REGIONS? 5-25
5.3.1 Introduction 5-25
5.3.2 Indicators 5-29
INDICATOR: Cancer Incidence 5-31
INDICATOR: Childhood Cancer Incidence 5-35
INDICATOR: Cardiovascular Disease Prevalence and Mortality 5-37
INDICATOR: Chronic Obstructive Pulmonary Disease Prevalence and Mortality....5-43
INDICATOR: Asthma Prevalence 5-48
INDICATOR: Infectious Diseases Associated with Environmental Exposures or
Conditions 5-53
INDICATOR: Birth Defects Rates and Mortality 5-58
INDICATOR: Low Birthweight 5-62
INDICATOR: Preterm Delivery 5-65
5.3.3 Discussion 5-67
What These Indicators Say About Trends in Diseases and Conditions for Which
Environmental Contaminants May Be a Risk Factor 5-67
Limitations, Gaps, and Challenges 5-68
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5.4 WHAT ARE THE TRENDS IN HUMAN EXPOSURE TO ENVIRONMENTAL
CONTAMINANTS, INCLUDING ACROSS POPULATION SUBGROUPS AND
GEOGRAPHIC REGIONS? 5-72
5.4.1 Introduction 5-72
5.4.2 Indicators 5-74
INDICATOR: Blood Lead Level 5-76
INDICATOR: Blood Mercury Level 5-79
INDICATOR: Blood Cadmium Level 5-82
INDICATOR: Blood Persistent Organic Pollutants Level 5-85
INDICATOR: Urinary Pesticide Level 5-94
INDICATOR: Urinary Phthalate Level 5-100
5.4.3 Discussion 5-105
What These Indicators Say About Trends in Exposure to Environmental
Contaminants 5-105
Limitations, Gaps, and Challenges 5-105
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1 5.1 INTRODUCTION
2 The health of the human population can be influenced by many factors, one of which is exposure to
3 environmental contamination. Protecting human health from the effects of environmental contaminants is
4 therefore an integral part of EPA's mission. Protecting, sustaining, or restoring the health of people and
5 communities is central to EPA's various research and regulatory programs. EPA examines the human
6 health impacts of contamination in air, in water, and on the land. Thorough study of adverse health effects
7 associated with environmental exposures enable the Agency to evaluate harmful levels of exposure and
8 issue guidelines for the safe production, handling, and management of hazardous substances.
9 As described in Chapters 2 through 4, people are exposed to environmental contaminants in a variety of
10 ways, and many contaminants are known to be or suspected of causing human disease. Identifying the
11 extent to which human exposures may be occurring or may have occurred and measures of health
12 outcomes possibly influenced by environmental exposures is important in determining where further
13 study or public health interventions may be necessary. For example, a high or increasing rate of a
14 particular cancer for which a hazardous substance in the environment is believed to be a contributing
15 factor is of interest. Similarly, the presence or patterns of elevated levels of environmental contaminants
16 as measured in human tissue through biomonitoring is also of interest. In addition, tracking health
17 condition and exposures across various segments of the population such as gender, race or ethnicity, or
18 geographic location helps to identify differences across subgroups and guide public health decisions and
19 strategies.
20 In this chapter, EPA seeks to assess trends in human disease and exposure that may be associated with
21 environmental factors on a national scale. Health outcome and biomonitoring indicators are presented to
22 address three fundamental questions:
23 • What are the trends in health status in the United States? Here the report uses several
24 general health outcome indicators (life expectancy, infant mortality, and general mortality) to
25 provide a broad picture of health in the United States. Trends in these indicators provide a
26 general context for understanding trends in specific diseases and conditions that may be
27 linked with the environment.
28
29 • What are the trends in human disease and conditions for which environmental
30 contaminants may be a risk factor, including across population subgroups and geographic
31 regions? This question looks at the occurrence of diseases and conditions that are known or
32 suspected to be caused to some degree or exacerbated by exposures to environmental
33 contaminants. This chapter uses a spectrum of indicators for health outcomes such as cancer,
34 asthma, and birth outcomes to address this question. Both morbidity and mortality statistics
35 are considered.
36
37 • What are the trends in human exposure to environmental contaminants, including across
38 population subgroups and geographic regions? Data on trends in exposure levels provide an
39 opportunity to evaluate the extent to which environmental contaminants are present in human
40 tissue, independent of the occurrence of specific diseases or conditions. To address this
41 question, this chapter focuses on biomonitoring indicators (or biomarkers of exposure) for
42 environmental contaminants such as lead, mercury, and pesticides.
43 These ROE questions are posed without regard to whether indicators are available to answer them. This
44 chapter presents the indicators available to answer these questions, and also points out important gaps
45 where nationally representative data are lacking.
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1 This chapter is not intended to be exhaustive in addressing these questions, nor is it intended to be a risk
2 assessment or epidemiological study. Rather, it provides an overview of selected indicators of human
3 disease and exposure over space and time based on key data sources with sufficiently robust design and
4 quality assurance.
5 The indicators used here are based on data sets representative of the national population; they are not
6 based on data from targeted populations or tied to specific exposures or releases. Therefore, these data
7 sets cannot and should not be used to draw conclusions about linkages or causal relationships between a
8 particular health outcome or contaminant; nor is it possible to directly link the health outcome or
9 biomonitoring indicators to any of the indicators of emissions or ambient pollutants in air, land, or water
10 presented in earlier chapters of this report. Though the chapter does not assess quantitative relationships
11 between the measures of environmental contaminants and diseases, it does present some qualitative
12 discussion of the research that has examined some of these relationships.
13
14 5.1.1 The Environmental Public Health Paradigm
15 The relationship among and between environmental pollution, exposure, and disease is complex.
16 Development of disease is multi-faceted. Relationships between environmental exposures and various
17 health outcomes can only be established through we 11-designed epidemiological, toxicological, and
18 clinical studies. An understanding of these factors is critical to providing the proper context for this
19 chapter.
20 The environmental public health paradigm shown in Exhibit 5-1 illustrates the broad continuum of factors
21 or events that may be involved in the potential development of human disease following exposure to an
22 environmental contaminant. This series of events serves as the conceptual basis for understanding and
23 evaluating environmental health. The exhibit illustrates that for adverse health effects to occur (clinical
24 disease or death) many things have to happen. A contaminant must be released from its source, reach
25 human receptors (via air, water, land), enter the human body (via inhalation, ingestion, or skin contact),
26 and be present within the body at sufficient doses within individuals to cause biological changes that may
27 ultimately result in an observed adverse health effect.
28 The paradigm, however, is a linear, schematic depiction of a process that is complex and multi-factorial.
29 Exposure to an environmental contaminant or stressor is rarely the sole cause of an adverse health
30 outcome. Environmental exposure is just one of several factors that may contribute to disease occurrence
31 or to the severity of a preexisting disease. Other factors include, for example, diet, exercise, alcohol
32 consumption, individual genetic makeup, medications, and other pre-existing diseases. It is known that
33 asthma, for example, can be triggered by environmental insult, but environmental exposures are not the
34 "cause" of all asthma attacks. In addition, different contaminants can be a risk factor for the same disease.
35 Taking the same example, outdoor air pollution and certain indoor air pollutants, such as environmental
36 tobacco smoke, can both exacerbate asthma symptoms. Further, susceptibility to disease is different for
37 each person; some individuals may experience effects from certain ambient exposure levels while others
38 may not.
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1 Each block in Exhibit 5-11 can have indicators associated with it. As shown, aspects of Chapters 2
2 through 4 may address contaminant formation, release, transport, and transformation in the environment.
3 Those chapters present indicators for the presence of contaminants or other stressors affecting air, water,
4 and land, sometimes at locations in which people may be exposed. Measurements of ambient exposure
5 levels are different than the biomonitoring indicators (biomarkers of exposures) introduced in this chapter.
6 Other types of biomarkers exist (e.g., biomarkers of susceptibility and biomarkers of effect); because
7 national-scale data do not exist for these biomarkers, they are not covered in this chapter at this time.
8 The presence of a contaminant in the environment or within human tissue alone does not mean disease
9 will occur. Furthermore, identification of diseases for which environmental contaminants are risk factors
10 does not mean exposure has occurred or contributed to that disease. However, extensive and collaborative
11 data collection and research efforts across the scientific community continue to strengthen our
12 understanding of the relationships between environmental exposures and disease.
Exhibit 5-1. Environmental public health paradigm
Adverse health
outcomes
Transport/transformation
in the ambient
environment
Altered
structure/function
^k
Exposure in the ambient
environment
Entry into body
(dose)
- Individual
-Community
- Population
'
Source: Adapted from Sexton etai, 1992
D Air, Water, and Land
(Chapters 2-4)
13
14
15
Establishing Linkages Between Environmental Contaminants and Health
Outcomes
16 Scientific research has helped identify linkages between exposure to environmental contaminants and
17 certain diseases, conditions, or other health outcomes. Examples include radon and lung cancer; arsenic
18 and cancer in several organs; lead and nervous system disorders; disease-causing bacteria such as E. coli
19 O157:h7 and gastrointestinal illness and death; and particulate matter and aggravation of cardiovascular
20 and respiratory diseases. Such relationships between exposure and disease have been established through
21 well-designed epidemiological studies with a defined or specified population (e.g., geographic location,
22 susceptible populations, occupational exposures) and known environmental exposures.
1 Adapted from: Sexton, K., S.G. Selevan, D.K. Wagener, and J.A. Lybarger. 1992. Estimating human exposures to
environmental pollutants: availability and utility of existing databases. Arch. Environ. Health 47(6):398-407.
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1 The causes of many diseases and other health conditions are not well established. In some cases
2 environmental contaminants are considered important risk factors. In other cases, available data suggest
3 that environmental exposures are important, but definitive proof is lacking. Developing conclusive
4 evidence that environmental contaminants cause or contribute to the incidence of adverse health effects
5 can be difficult, however, particularly for those effects occurring in a relatively small proportion of the
6 population or effects with multiple causes. In cases where exposure to an environmental contaminant
7 results in a relatively modest increase in the incidence of a disease or disorder, a large sample size for the
8 study would be needed to detect a true relationship. In addition, there may be factors that are related to
9 both the exposure and the health effect—confounding factors—that can make it difficult to detect a
10 relationship between exposure to environmental contaminants and disease. In many cases, findings from
11 studies in humans and/or laboratory animals may provide suggestive (rather than conclusive) evidence
12 that exposures to environmental contaminants contribute to the incidence of a disease or disorder.
13 EPA relies on the possible linkages established through the types of studies highlighted above to identify
14 environmental contaminants and health outcomes of potential Agency interest (e.g., the indicators used in
15 this chapter). To reiterate, however, the national-scale ROE indicators do not directly link exposure with
16 outcome and cannot be used to demonstrate causal relationships. However, when combined with other
17 information, such as environmental monitoring data and data from toxicological, epidemiological, or
18 clinical studies, these indicators can be an important key to improve the understanding of the relationship
19 between environmental contamination and health outcomes.
20 5.1.2 Overview of the Data
21 EPA draws on many resources and partnerships with other federal, state, and local agencies for the health
22 data and statistical reports that underlie the health outcome and biomonitoring indicators used in this
23 chapter. This report uses three key types of data sources, each with its own strengths and limitations:
24 • Vital statistics data. Vital statistics of interest for health include births, deaths, and fetal
25 deaths. Vital statistics data used in this report include the Centers for Disease Control and
26 Prevention (CDC's) National Center for Health Statistics' (NCHS') National Vital Statistics
27 System.
28
29 • Data collected from living human subjects. This includes both questionnaire-based
30 information (e.g., NCHS' National Health Interview Survey [NHIS], a nationwide survey to
31 collect data on personal and demographic characteristics, illnesses, and other topics) and
32 biological specimens (such as the NCHS' National Health and Nutrition Examination Survey
33 [NHANES], which collects and measures some chemicals in blood and urine samples). This
34 report focuses on data collection activities with a national focus and that use a probability-
35 based sampling design.
36
37 • Data from surveillance activities. These include data from active surveillance activities such
38 as the National Cancer Institute's (NCI's) Surveillance, Epidemiology, and End Results
39 (SEER) Program, which collects and publishes cancer incidence and survival data from
40 population-based cancer registries. It also includes data from more passive collection
41 systems, such as CDC's National Notifiable Disease Surveillance System, which provides
42 information about diseases that health providers must report to state or local public health
43 officials.
44 This report also takes advantage of several published documents that present and summarize in one place
45 the findings from many data collection activities (e.g., NCHS' Healthy People 2010 Database). In
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1 addition, it uses some databases that provide a single point of access to a variety of reports and numeric
2 public health data and ways to conduct analyses of those data (e.g., CDC's electronic database CDC
3 WONDER).
4 The data sources used provide statistics across time, geographic areas, and/or subpopulations such as age
5 groups, races, and ethnicities. Identifying possible differences among population subgroups, as well as
6 evidence of whether any differences are narrowing or widening, may reveal trends needing study or
7 intervention. This type of trend analysis is consistent with national public health goals aimed at
8 eliminating health disparities across various groups (e.g., racial and ethnic groups, low-income
9 populations).2 It addresses a continuing concern that minority and/or economically disadvantaged
10 communities frequently may be exposed disproportionately to environmental exposures and related
11 illnesses. Statistics for populations that may be particularly susceptible to environmental contaminants,
12 such as children and pregnant women, are also examined. However, the type and level of subpopulation
13 breakdown varies across data sets, sometimes making consistent presentation of this information difficult.
14 Standards that specify the way in which race and ethnicity statistics are reported across federal agencies
15 were revised in 1997. The standards, which became effective in 2003, expand the race and ethnicity
16 categories for which data are collected and are aimed at increasing comparability of data among federal
17 data systems. As vital records used to support federal data systems continue to be revised and come into
18 compliance with the 1997 requirements, future data reporting and comparisons will be more
19 straightforward.
20 This chapter presents health statistics, including race and ethnicity subgroup information, as reported
21 within the original data source documents or databases. The presentation of observed changes—
22 temporally, spatially, or across subgroups—is descriptive, not quantitative. No statistical testing was
23 performed (e.g., tests of statistical significance).
24 This chapter presents only data that meet the ROE indicator definition and criteria (see Chapter 1,
25 Introduction). Note that non-scientific indicators, such as administrative and economic indicators, are not
26 included in this definition. Thorough documentation of the indicators data sources and metadata can be
27 found online at . All indicators were peer-reviewed during an independent peer review
28 process (see for more information). Readers should not infer that the indicators included
29 reflect the complete state of the knowledge on trends in health and exposure related to environmental
30 exposures. Many other data sources, publications, site-specific research projects, and epidemiological
31 studies have contributed greatly to the current understanding of health and exposure trends, but are not
32 used because they do not meet some aspect of the ROE indicator criteria.
33 5.1.3 Organization of This Chapter
34 The rest of this chapter is organized into sections corresponding to the three questions EPA seeks to
35 answer about trends in human health and exposure. Each section introduces the question and its
36 importance, presents the national indicators selected to help answer the question, and discusses what the
37 indicators, taken together, say about the question. Each section concludes by highlighting the major
38 challenges to answering the question and identifying important gaps and limitations.
2 U.S. Department of Health and Human Services. 2000. Healthy people 2010: understanding and improving health.
Second ed. Washington, DC: U.S. Government Printing Office,
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1 The table below shows the indicators used to answer each of the questions in this chapter and where they
2 are found.
Table 5.1.1. Human Health—ROE Questions and Indicators
Question
What are the trends in health status in
the United States?
What are the trends in human disease
and conditions for which
environmental contaminants may be a
risk factor including across population
subgroups and geographic regions?
What are the trends in human
exposure to environmental
contaminants including across
population subgroups and geographic
regions?
Indicator Name
General Mortality (N)
Life Expectancy at Birth (N)
Infant Mortality (N)
Cancer Incidence (N)
Childhood Cancer Incidence (N)
Cardiovascular Disease Prevalence
(N) and Mortality (N/R)
Chronic Obstructive Pulmonary
Disease Prevalence (N) and
Mortality (N/R)
Asthma Prevalence (N)
Infectious Diseases Associated
with Environmental Exposures
or Conditions (N)
Birth Defects Rates and Mortality
(N)
Low Birthweight (N)
Preterm Delivery (N)
Blood Lead Level (N)
Blood Mercury Level (N)
Blood Cadmium Level (N)
Blood Persistent Organic Pollutants
Level (N)
Blood Cotinine Level (N)
Urinary Pesticide Level (N)
Urinary Phthalate Level (N)
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N/R = National Indicator displayed at EPA Regional scale
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1 5.2 WHAT ARE THE TRENDS IN HEALTH STATUS IN THE UNITED STATES?
2 5.2.1 Introduction
3 An overarching goal of public health agencies is to increase quality and years of healthy life and to
4 eliminate health disparities. Tracking historical trends in general health status can help identify where
5 interventions have improved the health of a population or where interventions may be needed (e.g.,
6 exploring causative factors and preventive measures). For example, a key concern for EPA is what
7 possible environmental factors could be contributing to the diseases or conditions that are the leading
8 causes of death in the United States. Tracking overall health in the United States therefore provides
9 important context for the next section of this chapter, which examines specific acute and chronic diseases
10 and conditions that may be linked with exposures to environmental contaminants.
11 The topics covered are broad and not intended to represent specific diseases or conditions related to the
12 environment. Environmental contaminants from air, water, and land can influence the overall health of a
13 nation; however, many factors other than the environment also influence the health of a population, such
14 as socio-demographic attributes, behavioral and genetic risk factors, level of preventive care, and quality
15 of and access to health care.
16 As defined by the World Health Organization (WHO), health is a state of complete physical, mental, and
17 social well-being, and not the mere absence of disease or infirmity.3 The health status of a population can
18 be measured by a wide range of factors: birth and death rates, life expectancy, quality of life, morbidity
19 from specific diseases, risk factors, use of ambulatory care and inpatient care, accessibility of health
20 personnel and facilities, financing of health care, health insurance coverage, and many other factors.4
21 While no single set of measures can completely characterize the health of a large and diverse population,
22 the CDC and other health agencies worldwide consistently have viewed life expectancy and mortality
23 data as indicators of overall population health because they represent the cumulative effects of social and
24 physical environmental factors, behavioral and genetic risk factors, and the level and quality of health
25 care. These data include the leading causes of mortality (among both infants and the general population),
26 which provide a broad perspective on the diseases and conditions that are having the greatest impact on
27 the nation's health. Infant mortality is a particularly useful measure of health status, because it indicates
28 both the current health status of the population and predicts the health of the next generation.5 It reflects
29 the overall state of maternal health as well as the quality and accessibility of primary health care available
30 to pregnant women and infants.
3 World Health Organization. 1946. Preamble to the constitution of the World Health Organization as adopted by the
International Health Conference, New York, 19-22 June, 1946; signed on 22 July 1946 by the representatives of 61
States (Official Records of the World Health Organization, no. 2, p. 100) and entered into force on 7 April 1948.
4U.S. Department of Health and Human Services. 2000. Healthy people 2010: understanding and improving health.
Second ed. Washington, DC: U.S. Government Printing Office,
5 National Center for Health Statistics. 2001. Healthy people 2000 final review. Hyattsville, MD: Public Health
Service,
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1 Tracking health status using such indicators provides information on changing or emerging trends. At the
2 beginning of the 20th century, the population of the United States was characterized by a low standard of
3 living, poor hygiene, and poor nutrition; communicable diseases and acute conditions were major causes
4 of most premature deaths. Over the course of the century, public health measures such as improved
5 sanitation and drinking water treatment led to a dramatic decrease in deaths due to infectious diseases and
6 a marked increase in life expectancy. As the population has aged, chronic diseases such as heart disease
7 and cancer have become the leading causes of death.6 These diseases may require a different approach to
8 prevention, detection, and treatment compared to the infectious and acute illnesses more common in the
9 past.
10 5.2.2 Indicators
11 Other agencies such as the CDC routinely assess the state of the nation's health. EPA has drawn on the
12 comprehensive data collection efforts and assessments conducted by these agencies in addressing this
13 question. Three indicators are used to assess the trends in health status in the United States (Table 5.2.1).
14 Life expectancy at birth is the number of years a newborn would expect to live if that person experienced
15 the mortality schedule existing at the time of birth. Infant mortality is the number of infants who die
16 before their first birthday. General mortality represents the number of all deaths nationwide and provides
17 information on the leading causes of death. Mortality is also tracked using years of potential life lost, or
18 the number of years "lost" by people in a population who die prematurely of a stated cause. These
19 indicators are interrelated—e.g., declines in mortality result in increased life expectancy, and shifts in life
20 expectancy are often used to describe changes in mortality; changes in infant mortality are reflected in
21 general mortality as well.
22 Where possible, the indicators for this question track health status among subpopulations (e.g., by gender,
23 race, ethnicity). Generally, differences in mortality and life expectancy between black and white
24 Americans have been tracked for the past several decades, in some cases as far back as the 1930s. A
25 broader spectrum of race and ethnic group breakdowns is available for these indicators in more recent
26 years, including American Indian/Alaskan Native, Asian or Pacific Islander, and Hispanic origin.
27 Subpopulation data are presented to the extent practicable under What the Data Show and/or within
28 indicator exhibits.
29 Table 5.2.1. ROE Indicators of Trends in Health Status in the United States
30
NATIONAL INDICATORS
General Mortality
Life Expectancy at Birth
Infant Mortality
LOCATION
5.2.2 -p. 5-13
5 .2.2 -p. 5-17
5.2.2 -p. 5-19
6 National Center for Health Statistics. 2001. Healthy people 2000 final review. Hyattsville, MD: Public Health
Service,
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INDICATOR: General Mortality
2 Overall mortality is a key measure of health in a population. Two measures of mortality are cause-specific
3 mortality and years of potential life lost (YPLL). All-cause mortality counts the total number of deaths
4 due to any cause within a specified year, whereas cause-specific mortality statistics count the number of
5 deaths due to a particular cause in a specified year. YPLL is defined as the number of years between the
6 age at death and a specified age; that is, the total number years which are "lost" by persons in the
7 population who die prematurely of a stated cause. Ranking the causes of death can provide a description
8 of the relative burden of cause-specific mortality (NCHS, 2005).
9 This indicator is based on mortality data recorded in the National Vital Statistics System (NVSS), which
10 registers virtually all deaths nationwide from death certificate data. YPLL is calculated by subtracting the
11 age at death from a selected age (e.g., 65, 75, 85), then summing the individual YPLL across each cause
12 of death (CDC, 2006). Sixty-five was selected as the age for this indicator to focus on deaths more likely
13 to be attributable to preventable causes and less influenced by increasing age. The temporal coverage of
14 the data is from 1933 to 2003 and data are collected from all 50 States and the District of Columbia.
15 What the Data Show
16 As noted in 2003 Draft ROE, an increase in the
17 number of deaths in the United States has been
18 observed over the last few decades, reflecting the
19 increase in the size and aging of the population. The
20 number of deaths continued to increase in 2001, 2002,
21 and 2003 where 2,416,425; 2,443,387; and 2,448,288
22 deaths, respectively, were recorded, an increase
23 compared to 1999 (2,391,399 deaths). However, the
24 age-adjusted all cause mortality rates have declined
25 yearly since 1980 (except in years of influenza
26 outbreaks in 1983, 1985, 1988, 1993, and 1999) with
27 the most recent available rate of 832.7 deaths per
28 100,000 people in 2003. Exhibit 5-2 provides some
29 historical perspective on trends in the age-adjusted
30 mortality rates between 1940 and 2003, showing that
31 age-adjusted rates were nearly twice as high in 1940 as
32 they were in 2000. The largest declines in "all cause
33 mortality" rates since 1990 has occurred among black
34 males compared with white males and black and white
35 females.
Exhibit 5-2. Age-adjusted "all cause" mortality
rates in the U.S., 1940-2003ab
'00
"Rates are age-adjusted to the 2000 U.S.
standard population.
bMortality rates were not generally reported for
black males and black females prior to 1964.
Data source: NCHS, 2001,2006
36
37
38
39
40
41
The rank order of the leading causes of death has remained the same since 1999, as reported in 2003 Draft
ROE. Exhibits 5-3 and 5-4 present the leading causes of mortality and YPLL for 2003, respectively. The
three leading causes of death were heart disease, cancer, and stroke, accounting for about 60 percent of all
deaths. The YPLL ranking is different, with unintentional injuries, cancer, and heart disease comprising
the top three for this measure
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Exhibit 5-3. Leading causes of death in the U.S., 2003
Percent of all deaths
28.0
Number
of deaths
Cause of death
Heart disease
Cancer (malignant neoplasms)
Stroke (cerebrovascular)
685,089
556,902
157,689
Chronic lower respiratory diseases 126,382
Accidents (unintentional injuries) 109,277
Diabetes mellitus
Influenza and pneumonia
Alzheimer's disease
Nephritis, nephritic syndrome
Septicemia
All other causes
74,219
65,163
63,457
42,453
34,069
533,588
Data source: CDC Web-Based Injury Statistics Query and Reporting System
(WISQARS) database
Exhibit 5-4. Years of potential life lost (YPLL) before age 65 in
the U.S., 2003
Cause of death YPLL
Accidents (unintentional injuries) 2,174,210
Cancer (malignant neoplasms) 1,899,078
Heart disease
Perinatal period
Suicide
Homicide
Congenital anomalies
HIV
Stroke (cerebrovascular)
Liver disease
All other causes
Percent of all YPLL
1,448,352
933,513
661,520
582,582
484,702
280,127
245,882
237,006
2,782,968
Data source: CDC Web-Based Injury Statistics Query and Reporting System
(WISQARS) database
23.7
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1 During 2003, heart disease was the leading cause of death across the reported racial and ethnic groups and
2 this was generally the case after further stratifying by race/ethnicity and gender. For Asians or Pacific
3 Islanders, however, cancer (malignant neoplasms) was the leading cause of death. In addition, diabetes
4 was ranked as the fourth leading cause of death among blacks and American Indian/Alaska Natives (both
5 sexes), which was a higher ranking than for most of the other racial and ethnic groups. (Data not shown).
6 Indicator Limitations
7 • Cause of death rankings denote the most frequently occurring causes of death among those
8 causes eligible to be ranked. The rankings do not necessarily denote the causes of death of
9 greatest public health importance. Further, rankings of cause-specific mortality could change
10 depending on the defined list of causes that are considered and, more specifically, the types of
11 categories and subcategories that are used for such rankings (NCHS, 2005).
12 • Mortality rates are based on underlying cause-of-death as entered on a death certificate by a
13 physician. Incorrect coding and low rates of autopsies that confirm the cause of death may
14 occur. Additionally, some individuals may have had competing causes of death. "When more
15 than one cause or condition is entered by the physician, the underlying cause is determined by
16 the sequence of conditions on the certificate, provisions of the ICD [International
17 Classification of Diseases], and associated selection rules and modifications" (CDC, n.d.).
18 Consequently, some misclassification of reported mortality might occur as a result of these
19 uncertainties, as well as the underreporting of some causes of death.
20 Data Sources
21 Mortality rates were obtained from vital statistics reports published by CDC's National Center for Health
22 Statistics (NCHS, 2001, 2006). Data in the NCHS reports are based in part on unpublished work tables,
23 available on the NCHS web site at http://www.cdc.gov/nchs/deaths .htm. Leading cause of death and
24 YPLL data were extracted from CDC's Web-Based Injury Statistics Query and Reporting System
25 (WISQARS) (CDC, 2006) (http://www.cdc.gOv/ncipc/wisaars/V The underlying data in WISQARS come
26 from CDC/NCHS annual mortality data files.
27 References
28 CDC (Centers for Disease Control and Prevention). 2006. National Center for Injury Prevention and
29 Control. Web-based Injury Statistics Query and Reporting System (WISQARS) [online]. Leading causes
30 of death and years of potential life lost (YPLL) reports, 1999-2003. Accessed 2006.
31
32
33 CDC (Centers for Disease Control and Prevention), n.d. CDC WONDER: Help page for compressed
34 mortality file,
35 NCHS (National Center for Health Statistics). 2006. Deaths: final data for 2003. National Vital Statistics
36 Reports 54(13). April 19.
37 NCHS (National Center for Health Statistics). 2005. Deaths: leading causes for 2002. National Vital
38 Statistics Reports 53(17).
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1 NCHS (National Center for Health Statistics). 2001. Age-adjusted death rates; trend data based on the
2 year 2000 standard population. National Vital Statistics Reports 49(9).
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INDICATOR: Life Expectancy at Birth
2 Life expectancy at birth is often used to appraise the overall health of a given population (NCHS, 2005).
3 Changes in life expectancy overtime are commonly used to describe trends in mortality. Life expectancy
4 is the average number of years at birth a person could expect to live if current mortality trends were to
5 continue for the rest of that person's life.
6 This indicator is based on data from the National Vital Statistics System (NVSS), which registers
7 virtually all deaths and births nationwide. The temporal coverage of the data is from 1933 to 2003 and
8 data are collected from all 50 States and the District of Columbia.
Exh b 15 5 Life expectancy in the U S by race
and sex, 1940 2003
9
0
31
32
33
What the Data Show
Exhibit 5-5 presents the historical trends in life
expectancy for the entire population as well as by
gender and race (black and white) between 1940 and
2003 showing an upward trend in life expectancy in the
United States overtime. Life expectancy at birth has
increased throughout the 20th and now into the 21st
century. The overall life expectancy was a record high
in 2003 at 77.5 years, a slight increase from 77.0 years
in 2000, 77.2 years in 2001, and 77.3 in 2002. This
follows seven consecutive years of increases.
Life expectancy continues to increase for both males
(73.9 years in 1999 to 74.8 years in 2003) and females
(79.4 years in 1999 to 80.1 years in 2003). The gap in
life expectancy between males and females widened
from 2.0 years to 7.8 years between 1900 and 1979.
Recently, this gap narrowed for the year 2000 and
remained relatively constant through 2003 with a
difference of 5.3-5.4 years between males and females.
(Data not shown.)
The increase in life expectancy among blacks reported for 1999 continued in 2001, 2002, and 2003 at
72.2, 72.3, 72.7 years, respectively. The difference in life expectancy between the black and white
populations was 5.3 years in 2003. In 2003, white females continued to have the highest life expectancy at
80.5 years, followed by black females at 76.1 years, white males at 75.3 years and black males at 69.0
years (Exhibit 5-5).
34 Indicator Limitations
35
36
37
38
Life expectancy at birth is strongly influenced by infant and child mortality rates. It is
important to consider such influences when making comparisons among subgroups since
differences in life expectancy among certain subgroups may be mostly attributed to
differences in prenatal care and other important determinants of infant and child mortality.
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1 Data Sources
2 The annual life expectancy data used for this indicator were obtained from life tables published by CDC's
3 National Center for Health Statistics (NCHS, 2006a). NCHS also publishes life expectancy data in its
4 annual "deaths: final data" reports (e.g., NCHS, 2006b); however, these reports generally provide year-
5 by-year breakdowns beginning in 1975. NCHS life table reports provide annual data back to before 1940.
6 Life table methodologies used to calculate life expectancies are presented in each of these NCHS reports.
7 References
8 NCHS (National Center for Health Statistics). 2006a. United States life tables. National Vital Statistics
9 Reports 54(14). Table 12. April 19. http://www.cdc.gov/nchs/data/nvsr/nvsr54/nvsr54_ 14.pdf
10 NCHS (National Center for Health Statistics). 2006b. Deaths: final data for 2003. National Vital Statistics
11 Reports 54(13). Table 8. April 19.
12 NCHS (National Center for Health Statistics). 2005. Health, United States, 2005, with chartbook on
13 trends in the health of Americans. DHHS Publication No. 2005-1232. Hyattsville, MD.
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INDICATOR: Infant Mortality
2 Infant mortality is a particularly useful measure of health status because it indicates both current health
3 status of the population and predicts the health of the next generation (NCHS, 2001). Infant mortality in
4 the United States is defined as the death of an infant from time of live birth to the age of 1 year. It does
5 not include still births. Overall infant mortality is comprised of neonatal (<28 days after birth) and
6 postneonatal (28 days to 11 months after birth) deaths.
7 This indicator presents infant mortality for the U.S. based on mortality data from the National Vital
8 Statistics System (NVSS) based on death certificate data. The NVSS registers virtually all deaths and
9 births nationwide with data coverage from 1933 to 2003 and from all 50 states and the District of
10 Columbia.
Exhibit 5-6. Infant mortality rates in the U.S. by
race and sex, 1940-2003a'b
100
:= 80
15
-------
1 Congenital anomalies were generally ranked highest among the different racial groups. However, the
2 leading cause of infant mortality among blacks was short gestation and low birth weight followed by
3 congenital anomalies. There were few differences in the leading causes of infant mortality between
4 Hispanics and non-Hispanics. In addition, CDC reports a substantial difference in the leading causes of
5 death during the neonatal versus the postneonatal periods. Disorders related to short gestation were the
6 leading cause of death for neonates and sudden infant death syndrome (SIDS) was the leading cause of
7 death for postneonates (CDC, 2005). (Data not shown.)
Exhibit 5-7. Leading causes of infant death in the U.S., 2003"
Number of deaths Percent of all infant deaths
5,621
4,849
8 Indicator Limitations
Cause of death
Congenital malformations, deformations, and chromosomal abnormalities
Disorders related to short gestation and low birthweight
Sudden infant death syndrome (SIDS)
Newborn affected by maternal complications of pregnancy
Newborn affected by complications of placenta, cord, and membranes
Accidents (unintentional injuries)
Respiratory distress of newborn
Bacterial sepsis of newborn
Neonatal hemorrhage
Circulatory system disease
All other causes
'Infant deaths" are those occurring before the age of 1.
Data source: CDC Web-Based Injury Statistics Query and Reporting System (WISQARS) database
9
10
11
12
13
14
15
16
17
18
19
20
21
Cause of death rankings denote the most frequently occurring causes of death among those
causes eligible to be ranked. The rankings do not necessarily denote the causes of death of
greatest public health importance. Further, rankings of cause-specific mortality could change
depending on the defined list of causes that are considered and, more specifically, the types of
categories and subcategories that are used for such rankings (NCHS, 2005)
Mortality rates are based on underlying cause-of-death as entered on a death certificate by a
physician. Incorrect coding and low rates of autopsies that confirm the cause of death may
occur. Additionally, some individuals may have had competing causes of death. "When more
than one cause or condition is entered by the physician, the underlying cause is determined by
the sequence of conditions on the certificate, provisions of the ICD [International
Classification of Diseases], and associated selection rules and modifications" (CDC, n.d.).
Consequently, some misclassification of reported mortality might occur as a result of these
uncertainties, as well as the underreporting of some causes of death.
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1 Data Sources
2 Infant mortality data were obtained from a published report by CDC's National Center for Health
3 Statistics (NCHS, 2006), which provides annual natality data back to 1975 and decadal data for 1940,
4 1950, 1960, and 1970. Data in the NCHS report are based in part on unpublished work tables, available
5 on the NCHS web site at http://www.cdc.gov/nchs/deaths.htm. Leading cause of infant death data were
6 extracted from CDC's Web-Based Injury Statistics Query and Reporting System (WISQARS) (CDC,
7 2006) (http://www.cdc.gov/ncipc/wisqars/). The underlying data in WISQARS come from CDC/NCHS
8 annual mortality data files.
9 References
10 CDC (Centers for Disease Control and Prevention). 2006. National Center for Injury Prevention and
11 Control: Web-Based Injury Statistics Query and Reporting System (WISQARS) [online]. Leading causes
12 of death reports, 1999-2003. Accessed 2006.
13 CDC (Centers for Disease Control and Prevention). 2005. QuickStats: leading causes of neonatal and
14 postneonatal deaths—United States, 2002. MMWR 54(38):966.
15
16 CDC (Centers for Disease Control and Prevention), n.d. CDC WONDER: Help page for compressed
17 mortality file,
18 NCHS (National Center for Health Statistics). 2006. Deaths: final data 2003. National Vital Statistics
19 Reports 54(13). April 19.
20 NCHS (National Center for Health Statistics). 2005. Deaths: leading causes for 2002. National Vital
21 Statistics Reports 53(17).
22 NCHS (National Center for Health Statistics). 2001. Healthy people 2000 final review. Hyattsville, MD:
23 Public Health Service,
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1 5.2.3 Discussion
2 What These Indicators Say About Trends in U.S. Health Status
3 ROE indicators used to answer this question show that the overall health of the nation has continued to
4 improve. The three leading causes of death across all age groups—heart disease, cancer, and stroke—
5 remain unchanged since 1999. In contrast, a ranking by years of potential life lost, which weighs more
6 heavily deaths at an earlier age, places unintentional injuries, cancer, and heart disease as the top three
7 (General Mortality indicator, p. 5-13). Although men and women in many other countries have longer life
8 expectancies, general mortality rates in the United States continue to decline, and life expectancy
9 continues a long-term upward trend (Life Expectancy indicator, p. 5-17). See the sidebar on the next page
10 for an overview of health status in the United States compared to the rest of the world.
11 The decline in the all-cause mortality rate since 1940 has been driven largely by declines in deaths from
12 heart disease, stroke, and unintentional injuries. These trends have been linked in part to the resources
13 devoted to health education, public health programs, health research, and health care, and the impact of
14 these efforts on controlling disease. For example, public campaigns about smoking and the use of
15 cholesterol-lowering drugs have contributed to a decline in the death rate from heart disease. Efforts to
16 improve motor vehicle safety as well as safety in homes and workplaces have helped to lower death rates
17 from unintentional injuries. New medical treatments have resulted in a decline in the death rate from
18 HIV.7
19 Infant mortality (p. 5-19), like the other two indicators, shows a long-term decline, likely due to
20 widespread application of advances in medical knowledge (such as the introduction of synthetic
21 surfactant for preterm infants and widespread public education about infant sleep position).8 However,
22 infant mortality in the United States remains among the highest in the industrialized world, and in 2002 a
23 slight increase in rate was reported for the first time since 1958. This rate dropped back slightly in 2003.
24 This recent rise in infant mortality is attributed to an increase in neonatal deaths (infants less than 28 days
25 old), particularly deaths of infants within the first week of life.9
26
7 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD. p. 3.
8 National Center for Health Statistics. 2001. Healthy people 2000 final review. Hyattsville, MD: Public Health
Service, p. 206.
9 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD. p. 66.
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Worldwide Comparisons in Health Status
The following comparisons are based on the most current statistics for each of the three indicators
used to study U.S. health status. The WHO calculates its statistics to ensure comparability across
data sets; the statistics may not fully match those generated by individual countries and reported in
other reports.
Life Expectancy. According to the World Health Organization (WHO), in 2003, the United States
ranked 34th in terms of life expectancy for males and 35th for females of the 192 WHO member
states.1 Japan reports the highest life expectancy (82 years, compared to the U.S life expectancy of
77 years reported by WHO).
Leading Causes of Death. The leading causes of death reported in the United States in 2002 were
heart disease, cancer, and stroke. Worldwide, cardiovascular diseases accounted for the largest
percentage of deaths, followed by infectious and parasitic diseases and cancer.2
Infant mortality. In 2002, the United States ranked 28th among the 37 countries, territories, cities, or
geographic areas with at least 1 million population considered to have completed counts of live births
and infant deaths as indicated in the United Nations Demographic Yearbook.3 The U.S. infant
mortality rate for the same time period (7.0 per 1,000 live births) was approximately 2-3 times higher
than the lowest rates reported worldwide (e.g., in Hong Kong the rate was 2.3, Sweden the rate was
2.8, Singapore the rate was 2.9, and Japan the rate was 3.0, per 1,000 live births).
1 WHO. 2005. World Health Report. See Statistical Annex Table 1. http://www.who.int/entitv/whr/2005/annex/annex1.xls
2 WHO 2005. WHO Statistical Information System (WHOSIS). Estimates of numbers of deaths by sex, cause and WHO
mortality sub-region for 2002. http://www3.who.int/whosis/burden/estimates/2002/2002subreaion/dth14 2002.zip
3National Center for Health Statistics (NCHS). 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. Hyattsville, Maryland. DHHS Publication No. 2005-1232. Table 25. http://www.cdc.gov/nchs/data/hus/husQ5.pdf.
2 Despite a generally improving picture of the nation's health, racial and ethnic disparities in health status
3 persist. For example, though the nation's infant mortality rate has decreased, the infant death rate for
4 black infants is still more than double that of whites. In 2003, the gap in life expectancy between the
5 black and white populations is 5.3 years, though this gap has been narrowing.10 Differences in death rates
6 also exist between black and white populations. Observed differences are believed to be the result of a
7 complex interaction of genetic variations, environmental factors, and specific health behaviors.11
8 Differences also exist between men and women. Based on 2003 data, men have a life expectancy 5.4
9 years less than that of women and have higher death rates for each of the 10 leading causes of death.
10 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD. pp. 11-12.
11 U.S. Department of Health and Human Services. 2000. Healthy people 2010: understanding and improving health.
Second ed. Washington, DC: U.S. Government Printing Office,
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1 However, women have shown increased death rates over the past decade in areas where men have
2 experienced improvements, such as lung cancer.12
3 Limitations, Gaps, and Challenges
4 The indicators are important and widely accepted measures of population health status. However, the
5 selected indicators cannot be expected to fully answer the question on trends in general U.S. health status.
6 Limitations and information gaps are highlighted here.
7 The indicators provide a broad measure of health status and include many variables that are not related to
8 the environment. No conclusions, therefore, can or should be drawn about the role of exposure to
9 environmental contaminants using these indicators alone. While declining mortality rates and increasing
10 life expectancy suggest improving health status, these indicators do not address other aspects of health,
11 such as morbidity, perceived well-being, or quality of life.
12 The use of mortality data presents some limitations, largely related to uncertainties associated with the use
13 of death certificate data. First, correct coding of the underlying cause of death and confirmation by
14 autopsy may not occur. Second, uncertainties in intercensal population estimates can affect conclusions
15 about trends in data sets. In addition, improved data on the health status of population subgroups—
16 particularly across race and ethnic groups—would allow better characterization of potential trends across
17 different groups. Accurate identification of health disparities will require improved data collection and the
18 use of standardized data. For example, problems of race and Hispanic-origin classification can affect
19 Hispanic death rates and the comparison of rates across the Hispanic and non-Hispanic populations.13
20
12 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD. pp. 11-12.
13 National Center for Health Statistics. 2006. Deaths: final data 2003. National Vital Statistics Reports 54(13). April
19.
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1 5.3 WHAT ARE THE TRENDS IN HUMAN DISEASE AND CONDITIONS FOR
2 WHICH ENVIRONMENTAL CONTAMINANTS MAY BE A RISK FACTOR,
3 INCLUDING ACROSS POPULATION SUBGROUPS AND GEOGRAPHIC
4 REGIONS?
5 5.3.1 Introduction
6 As discussed throughout this report, numerous human diseases and conditions have been linked with
7 exposures to environmental contaminants, some more strongly than others. Identifying diseases that
8 might be associated with environmental contaminants, and determining the existing data sources available
9 for them, is a key part of the effort to better characterize links between environmental exposures and
10 adverse health outcomes.
11 Tracking overall rates of disease in the nation, independent of exposure, enables the evaluation of disease
12 patterns and emerging trends. It may identify diseases, conditions, and possible risk factors that warrant
13 further study or intervention and can help identify where policies or interventions have been successful.
14 Because the United States has a diverse population, an important component of such an analysis is
15 identifying disparities among people of differing races and ethnicities, genders, education and income
16 levels, and geographic locations.
17 EPA has selected those human diseases and conditions with well-established associations with exposures
18 to environmental contaminants and for which national data are available, recognizing again that in most
19 cases risk factors are multi-factorial. The diseases and conditions addressed in this question are associated
20 with the contaminant sources covered by the questions in the three media chapters (Chapters 2, 3, and 4)
21 of this report. As described in Section 5.1, however, this question is not intended to tie human diseases
22 and conditions to specific changes in the environment being measured at the national level. Covered
23 health outcomes fall into the following five broad categories: cancer, cardiovascular disease, respiratory
24 disease, infectious disease, and birth outcome. The reasons for the inclusion of each are highlighted
25 below.
26 Cancer
27 The term "cancer" refers to diseases in which abnormal cells divide without control, losing their ability to
28 regulate their own growth, control cell division, and communicate with other cells. Cancer is the second
29 leading cause of death in the United States (General Mortality indicator, p. 5-13). More than one in three
30 people will develop cancer and nearly one in four will die of it.14'15 In response, scientists continue to
31 explore the role that the exposure to environmental contaminants may play, along with other possible risk
32 factors, in the initiation and development of cancer. Some environmental exposures are known risk
33 factors for certain types of cancers. Examples include radon and lung cancer and arsenic and skin cancer.
34 Though many types of cancer may be related to environmental exposures, associations are not always
35 clear because the etiology of cancer is complex and influenced by a wide range of factors. Exposures may
36 include environmental contaminants in air, water, and soil but also result from exposure to sunlight,
14 American Cancer Society. 2005. Cancer facts and figures 2005. Atlanta.
15 National Toxicology Program. 2004. Report on carcinogens. Eleventh ed. U.S. Department of Health and Human
Services, Public Health Service,
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1 workplace exposures, and drugs. Other factors may increase individual cancer risk, such as age, genetics,
2 existence of infectious diseases, and socioeconomic factors that may affect exposure and susceptibility.
3 Childhood cancers are dissimilar from cancers in adults and are therefore tracked separately. They affect
4 different anatomic sites and may be of embryonic origin. Though overall cancer incidence rates are
5 relatively lower in children compared to adults, childhood cancers are the third leading cause of death in
6 children age 1-19 years.16 Children may be particularly susceptible to exposures in utero or during early
7 childhood because systems are rapidly developing and affected by evolving hormonal systems.17 As with
8 many adult cancers, the causes of childhood cancers are unknown for the most part; environmental
9 influences may be a factor and have been the subject of extensive research.
10 Cardiovascular Disease
11 More than one-fourth of the U.S. population lives with a cardiovascular disease, with more than 6 million
12 hospitalizations each year.18 Coronary heart disease and stroke, two of the major types of cardiovascular
13 disease, rank as the first and third leading causes of death, respectively (General Mortality indicator, p. 5-
14 13), and are leading causes of premature and permanent disabilities. Known risk factors include smoking,
15 high blood pressure, high blood cholesterol, diabetes, physical inactivity, and poor nutrition. Outdoor air
16 pollution and environmental tobacco smoke are also known risk factors for cardiovascular disease.
17 Particulate matter, for example, has been demonstrated to be a likely causal factor in both cardiovascular
18 disease morbidity and mortality. Environmental tobacco smoke has been shown to be a risk factor for
19 coronary heart disease morbidity and mortality and may contribute to stroke.19'20'21
20 Respiratory Disease
21 Chronic obstructive pulmonary disease (COPD) and asthma are two prevalent chronic respiratory diseases
22 in the United States. COPD is a group of diseases characterized by airflow obstruction, resulting in
23 breathing-related symptoms and encompasses chronic obstructive bronchitis and emphysema.22'23 COPD
16 National Center for Health Statistics. 2004. Deaths: final data for 2002. National Vital Statistics Reports 53(5).
17 Anderson, L.M., B.A. Diwan, N.T. Fear, and E. Roman. 2000. Critical windows of exposure for children's health:
cancer in human epidemiological studies and neoplasms in experimental animal models. Environ. Health. Perspect.
108(Suppl 3):573-594.
18 Centers for Disease Control and Prevention. 2005. Preventing heart disease and stroke. Addressing the nation's
leading killers—at a glance. Revised August 2005.
19 National Cancer Institute. 1999. Smoking and tobacco control monograph 10: health effects of exposure to
environmental tobacco smoke.
20 U.S. EPA. 2005. Review of the national ambient air quality. Standards for paniculate matter: policy assessment of
scientific and technical information. OAQPS Staff Paper.
21 U.S. EPA. 2004. Air quality criteria for paniculate matter. Volumes I (EPA/600/P-99/002aF) and II (EPA/600/P-
99/002bF). National Center for Environmental Assessmen-RTP Office, Office of Research and Development.
22 Mannino, D.M. 2002. COPD epidemiology, prevalence, morbidity and mortality, and disease heterogeneity. Chest
121:1218-1268.
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1 is the fourth leading cause of death in the United States and is the leading cause of hospitalization in U.S.
2 adults, particularly in older adults. It represents a major cause of morbidity, mortality, and disability.24
3 Asthma continues to receive attention in both children and adults. Asthma prevalence increased nearly 74
4 percent during 1980-1996.25
5 Epidemiological and clinical studies have shown that ambient and indoor air pollution are risk factors in
6 several respiratory health outcomes, including reported symptoms (nose and throat irritation), acute onset
7 or exacerbation of existing disease (e.g., asthma), and deaths. Environmental contaminants such as dust
8 mites, pets, mold, and other allergens are considered important triggers for asthma.26 In addition, the
9 relationship between environmental tobacco smoke and diseases of the respiratory tract has been studied
10 extensively in humans and in animals; environmental tobacco smoke has been shown to produce a variety
11 of upper and lower respiratory tract disorders ,27
12 Infectious Diseases
13 Infectious diseases are acute illnesses caused by bacteria, protozoa, fungi, and viruses. Food and water
14 contaminated with pathogenic microorganisms are the major environmental sources of gastrointestinal
15 illness. Though well-established systems for reporting food- and waterborne cases exist, data reported
16 through these largely voluntary programs must be interpreted with caution because many factors can
17 influence whether an infectious disease is recognized, investigated, and reported. Changes in the number
18 of cases reported could reflect actual changes or simply changes in surveillance and reporting. In addition,
19 many milder cases of gastrointestinal illnesses go unreported or are not diagnosed, making it difficult to
20 estimate the number of people affected every year.
21 The discovery of bacterial contamination of drinking water as the cause of many cases of gastrointestinal
22 illness represents one of the great public health success stories of the 20th century. Waterborne diseases
23 such as typhoid fever and cholera were major health threats across the United States at the beginning of
24 the 20th century. Deaths due to diarrhea-like illnesses, including typhoid, cholera, and dysentery,
25 represented the third largest cause of death in the nation at that time. These types of diarrheal deaths
26 dropped dramatically once scientists identified the bacteria responsible, elucidated how these bacteria
27 were transmitted to and among humans in contaminated water supplies, and developed effective water
28 treatment methods to remove pathogens from water supplies.
23 Barnes, P.J. 2000. Chronic obstructive pulmonary disease. Review article. N. Engl. J. Med. 343(4):269-280.
24 Mannino, D.M., D.M. Homa, L.J. Akinbami, et al. 2002. Chronic obstructive pulmonary disease surveillance—
United States, 1971-2000. In: Surveillance Summaries. MMWR 51(SS06):1-16.
25 Mannino, D.M., D.M. Homa, L.J. Akinbami, et al. 2002. Surveillance for asthma—United States, 1980-1999. In:
Surveillance Summaries. MMWR 51(SS-1):1-13.
26 U.S. Institute of Medicine. 2000. Clearing the air. Asthma and indoor air exposures. Washington, DC: National
Academy Press.
27 State of California. 2005. Proposed identification of environmental tobacco smoke as a toxic air contaminant. Part
B: health effects assessment for environmental tobacco smoke. As approved by the Scientific Review Panel on June
24, 2005. California Environmental Protection Agency, Office of Environmental Health Hazard Assessment.
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1 In addition to being of food- or waterborne origin, infectious disease can be airborne, arthropod-borne
2 (spread by mosquitoes, ticks, fleas, etc.), or zoonotic (spread by rodents, dogs, cats, and other animals).
3 Legionellosis can be contracted from naturally-occurring bacteria found in water and spread through
4 poorly maintained artificial water systems (e.g., air conditioning, ventilation systems). Arthropod-borne
5 diseases, including Lyme disease, Rocky Mountain Spotted Fever, and West Nile Virus, can be contracted
6 from certain ticks and mosquitoes that acquire bacteria or viruses by biting an infected mammal or bird.
7 Birth Outcomes
8 Birth defects are structural anomalies that are present in the fetus at birth, including those resulting from
9 chromosomal abnormalities. They affect approximately one out of 33 babies born each year in the United
10 States and remain the leading cause of infant mortality (Infant Mortality indicator, p. 5-19). Serious,
11 adverse effects on health, development, and functional ability may be experienced by individuals born
12 with birth defects.28 Birth defects have been linked with a variety of possible risk factors that can affect
13 normal growth and development—genetic or chromosomal aberrations, as well as environmental factors
14 such as exposure to chemicals; exposure to viruses and bacteria; and use of cigarettes, drugs, or alcohol
15 by the mother. Because the causes of most birth defects are unknown, public concern exists about
16 possible environmental links to birth defects.
17 Low birthweight delivery and preterm birth are considered important risk factors for infant mortality and
18 birth defects. Low birthweight infants have a significantly increased risk of infant death, and those who
19 survive are more likely to experience long-term developmental disabilities.29 Multiple birth babies have a
20 low birthweight rate of more than 50 percent, compared to approximately 6 percent among singletons,
21 among whom the low birth weight rate rose only 1 percent from 1989-1998.30 To eliminate the effect that
22 multiple births may have on birth outcomes, this report presents data for singleton births only.
23 Environmental exposures are being investigated for possible associations with birth outcomes such as low
24 birthweight, preterm births, and infant mortality. Some of the risk factors for low birthweight infants born
25 at term include maternal smoking, weight at conception, and nutrition and weight gain during
26 pregnancy.31 Specific examples of known or suspected environmental contaminant influences on these
27 birth outcomes include environmental tobacco smoke, air pollution, and lead. Environmental tobacco
28 smoke is associated with increased risk of low birthweight, preterm delivery, and sudden infant death
29 syndrome.32 Associations between air pollution and fetal growth and infant mortality have been
28 Centers for Disease Control and Prevention. 2006. Improved national prevalence estimates for 18 selected major
birth defects—United States, 1999-2001. MMWR 54(51&52):1301-1305.
29 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD. p. 11.
30 National Center for Health Statistics. 2001. Healthy people 2000 final review. Hyattsville, MD: Public Health
Service, p. 208.
31 U.S. Department of Health and Human Services. 2000. Healthy people 2010: understanding and improving health.
Second ed. Washington, DC: U.S. Government Printing Office,
32 State of California. 2005. Proposed identification of environmental tobacco smoke as a toxic air contaminant. Part
B: health effects assessment for environmental tobacco smoke. As approved by the Scientific Review Panel on June
24, 2005. California Environmental Protection Agency, Office of Environmental Health Hazard Assessment.
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1 documented, but more evidence is needed to establish causal relationships between air pollution and
2 preterm birth.33 Several studies also have identified lead as a risk factor for preterm delivery.34
3 Researchers continue to examine possible associations between other contaminants as birth outcome risk
4 factors, such as pesticides, polycyclic aromatic hydrocarbons, among others.
5 5.3.2 Indicators
6 EPA has selected indicators of health outcomes for which environmental exposures may be a risk factor
7 and for which nationally representative data are available. Nine indicators were selected to address the
8 question (Table 5.3.1)—two for cancer (including the leading sites of cancer in adults and children), one
9 for cardiovascular disease (including coronary heart disease, stroke, and hypertension), two related to
10 respiratory disease (including asthma and chronic lung conditions such as bronchitis and emphysema),
11 one for infectious diseases (comprised of multiple diseases and conditions), and three for birth outcomes.
12 The indicators used to answer this question are drawn from CDC's vital statistics and surveillance data,
13 including the CDC WONDER Mortality Database, Summary of Notifiable Diseases, NCHS' s National
14 Vital Statistics Reports, Summary Health Statistics for the U.S., and National Health Interview Survey, as
15 well as the National Cancer Institute's (NCI's) Surveillance, Epidemiology, and End Results (SEER)
16 Database. The time frames covered generally range back to the 1970s for mortality and incidence data
17 and to the mid-1990s for prevalence data.
18 In answering this question, both disease morbidity (incidence or prevalence) and mortality (resulting
19 death) statistics are used. Depending on the health outcome of interest, both measures can provide useful
20 insights about trends in disease. Both morbidity and mortality statistics are influenced by a number of
21 factors, however, such as the accuracy of reporting mechanisms, and issues related to access to, quality
22 of, and advances in medical care. An overall understanding of the disease measures and associated
23 statistics used to answer this question is important.35
33 Sram R.J., B. Binkova, J. Dejmek, and M. Bobak. 2005. Ambient air pollution and pregnancy outcomes: a review
of the literature. Environ. Health. Perspect. 113(4):375-382.
34 Agency for Toxic Substances and Disease Registry. 2005. Toxicological profile for lead (update). Draft for public
comment. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
35 Both morbidity and mortality can be measured using occurrences or rates. Occurrences represent frequency
counts, while rates enable a comparison across populations. Rates are ratios that calculate the frequency of cases (of
disease, condition, outcome) divided by the size of the defined population for a specified time period. Usually some
constant (generally a multiplier of the power 10) is applied to convert the rate to a whole number.
Morbidity data are often used to describe the incidence and prevalence of a disease or condition. Both incidence and
prevalence are often expressed as a rate per 1,000 persons over a particular time period. Incidence refers to the
number of new cases of a disease or condition in a population during a specified time period. Prevalence refers to
the total number of people with a given disease or condition in a population at a specified point in time.
Mortality is generally expressed as a rate and is defined as the proportion of the population who die of a disease or
condition during a specified time period. The rate is usually calculated for a calendar year and is often expressed per
100,000 persons.
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1
2
3
4
5
6
7
Where possible, breakouts of population subgroups are provided, such as race, ethnicity, age, and gender.
Subpopulation data are presented to the extent practicable under What the Data Show, within text or
shown in indicator figures. For cardiovascular and respiratory diseases, mortality statistics are provided
for each of the 10 EPA Regions. For cancer, data for the most frequently diagnosed cancer sites in adults
and children, along with overall cancer rates, are used to answer the question.
Table 5.3.1. ROE Indicators of Trends in Human Disease and Conditions for Which Environmental
Contaminants May Be a Risk Factor Including Across Population Subgroups and Geographic
Regions
NATIONAL INDICATORS
Cancer Incidence
Childhood Cancer Incidence
Cardiovascular Disease Prevalence and Mortality (N/R)
Chronic Obstructive Pulmonary Disease Prevalence and Mortality (N/R)
Asthma Prevalence
Infectious Diseases Associated with Environmental Exposures or
Conditions
Birth Defects Rates and Mortality
Low Birthweight
Preterm Delivery
LOCATION
5.3.2 -p. 5-31
5.3.2 -p. 5-35
5.3.2 -p. 5-37
5.3.2 -p. 5-43
5.3.2 -p. 5-48
5.3.2 -p. 5-53
5.3.2 -p. 5-58
5.3.2 -p. 5-62
5. 3.2 -p. 5-65
9 N/R = National Indicator displayed at EPA Regional scale
Incidence, prevalence, and mortality statistics may be used to compare the rates of disease at two or more points in
time, across different populations (ages, gender, racial/ethnic groups), or between different geographic areas. In
general, disease incidence, prevalence, and mortality increase with age. For this reason, when comparing different
populations, the data must be adjusted to account for the age differences between the populations. The adjusted data,
called "age-adjusted rates," are used where possible in answering this question. Age-adjusted rates are weighted
sums of age-specific rates and calculated using standard population factors (In this report, the 2000 U.S. standard
population was used). Unadjusted rates are referred to as "crude" rates.
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NDICATOR: Cancer Incidei
2 The term "cancer" is used to characterize diseases in which abnormal cells divide without control. A
3 cancerous cell loses its ability to regulate its own growth, control cell division, and communicate with
4 other cells. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic
5 system to other parts of the body (NCI, n.d.). The risk of developing cancer increases with age and the
6 environment (as broadly defined), genetic predisposition, certain viruses, and socioeconomic factors may
7 all play a role in the development and progression of the disease.
8 For the U.S. population, age-adjusted cancer incidence rates for all sites combined have been stable since
9 1992 (Edwards et al., 2005). Nevertheless, cancer continues to be the second leading cause of death in the
10 United States, accounting for about 23 percent of all deaths in 2003 (General Mortality indicator, p. 5-13)
11 (NCHS, 2006). Many different types of cancer exist. These may develop in various organs and tissues
12 within the body and contributing causal factors may vary depending on the cancer site and type.
13 Therefore, tracking rates for individual cancer sites is more meaningful when evaluating cancer trends.
14 The contribution of environmental factors to the development of various cancers has been and continues
15 to be a major focus of research. Factors including individual food and beverage preferences, use of
16 tobacco products, exposure to natural and medical radiation (including sunlight), workplace exposures,
17 and pharmaceutical use as well as exposure to substances in the air, water and soil all may contribute
18 individually (additive) or synergistically (i.e., an effect greater than the sum of each factor acting alone) to
19 the development of cancer (NTP, 2004). Only in a small number of cases, however, is it known what
20 specific environmental factor(s) or condition(s) are responsible for the onset and development of cancers
21 (NTP, 2004).
22 This indicator presents cancer incidence rates for the U.S. population using data collected through the
23 National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. The SEER
Program collects and publishes cancer incidence and
survival data from 14 population-based cancer
registries and three supplemental registries covering
approximately 26 percent of the U.S. population. The
10 most commonly diagnosed cancer sites presented
are based on 2003 data compiled from SEER. Site
classifications (e.g., lung and bronchus; colon and
rectum) were compared to the American Cancer
Society's "leading sites" classification to ensure
consistency in how data are presented (ACS, 2003).
Exh b 15 8 Age adjusted cancer incidence
rates in the U S , 1973 2003 All cancer sites for
all ages, by race and sex3
1000
'80
'85 '90
Year of diagnosis
'95
'00
"Rates are age adjusted to the 2000 U S
standard population
Data source: NCI. Surveillance,
Epidemiology, and End Results (SEER)
Database
What the Data Show
Although a slow steady increase in cancer incidence
occurred between 1973 and 1992 peaking in 1992 with
an age-adjusted cancer incidence of 510 cases per
100,000, overall incidence rates appear to have
stabilized over the last ten years (Exhibit 5-8). Some
differences exist in incidence rates across age, gender,
and racial groups. During 2003, those age 65 and older
had the highest incidence rates (2,109.1 cases per
100,000) compared to all other age categories (data not
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5-31
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1 shown). Total (all sites combined) cancer incidence rates are higher for males compared to females and
2 for black males compared to white males (Exhibit 5-8). The age-adjusted cancer incidence rate in 2003
3 for black males was 650.4 cases per 100,000 compared to 541.3 cases per 100,000 for white males;
4 among females, the age-adjusted cancer incidence rate in 2003 was 417.3 cases per 100,000 for white
5 females compared to 397.6 cases per 100,000 among black females, showing a slight decrease from 2002.
6 Exhibit 5-9 shows the differences between the top ten cancer sites in males and females. For both, the top
7 three cancers represent over half of all newly identified cancer cases in 2003. Among the most notable
8 differences is the rate of urinary bladder cancer among males (36.4 cases per 100,000), which is more
9 than three times that of females (9.4 cases per 100,000). Melanoma of the skin is also higher among males
10 (23.0 cases per 100,000) than females (15.8 cases per 100,000). Thyroid cancer appears as the seventh
11 leading cancer in females (14.0 cancers per 100,000), but is not among the top ten for males (4.6 cases per
12 100,000).
Exhibit 5-9. Age-adjusted cancer incidence rates in the U.S., 2003: Ten leading cancer sites by sex3
Percent of all cancers
30.5
6.71
4.4 •
4.3 •
3.21
2.91
2.81
2.31
17.71
Rate0 Male
164.9 Prostate
78.5 Lung and bronchus
58.0 Colon and rectum
36.4 Urinary bladder
23.6 Non-Modgkin's lymphoma
23.0 Melanoma of the skin
17.5 Kidney and renal pelvis
15.4 Leukemia
15.2 Oral cavity and pharynx
12.5 Pancreas
NCd All other sites
Female Rate0
Breast 124.2
Lung and bronchus 51.3
Colon and rectum 42.8
Corpus uteri 23.3
Non-Modgkin's lymphoma 16.9
Melanoma of the skin 15.8
Thyroid 14.0
Ovary 13.2
Pancreas 10.2
Urinary bladder 9.4
All other sites NCd
Percent of all cancels
|5.8
14.2
13.9
13.5
13.3
|25
12.3
20.5
"Excludes basal and squamous cell skin cancers and in situ carcinoma, except urinary bladder.
'Percentages may not total 100% due to rounding.
°Rates are per 100,000 and age-adjusted to the 2000 U.S. standard population.
dNC = not calculated
Data source: NCI. Surveillance, Epidemiology, and End Results (SEER) Database
13 Among males, prostate cancer incidence rates increased dramatically between 1986 and the early 1990s,
14 with a decline in rates between 1992 and 1995. This increase is likely due to the introduction of serum
15 prostate-specific antigen (PSA) testing for the early detection and screening of prostate cancer (Hankey et
16 al., 1999). The other four leading cancers (colon and rectum, lung and bronchus, urinary bladder, and
17 non-Hodgkin's lymphoma) have either been relatively stable or have showed a small decline over the last
18 decade (Exhibit 5-10).
19 Recent trends (i.e., since 1995) among the less prevalent site-specific cancers in males show small
20 increases in the incidence rates for melanoma of the skin (melanoma), which ranged from 20.2 (1995) to
21 24.1 (2001) cases per 100,000, and cancers of the kidney and renal pelvis (kidney), which ranged from
22 15.0 (1997) to 17.6 (2002) cases per 100,000. Slightly decreasing rates were observed for leukemia,
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5-32
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Exhibit 5-10. Age-adjusted cancer incidence
rates in the U.S., 1973-2003: Top five cancers in
males of all ages3
250
200
150
100
50
75
'80
'85 '90
Year of diagnosis
"Rates are age-adjusted to the
2000 U.S. standard population.
Data source: NCI. Surveillance,
'95
'00
Epidemiology, and End Results
(SEER) Database
— Colon and rectum
Lung and bronchus
— Non-Hodgkin's lymphoma
Prostate
— Urinary bladder
which ranged from 17.5 (1995) to 15.4 (2003) cases per
100,000, and cancers of the oral cavity and pharynx
(oral cavity), which ranged from 17.6 (1996) to 15.2
(2003) cases per 100,000. (Data not shown.).
As shown in Exhibit 5-11, among females, breast
cancer remains the leading cancer and rates have
generally increased for much of the reporting period.
While lung cancer among males has slowly declined
over the past decade, the rate among women has
increased over the last decade and has become the
second leading cancer among men and women in 2003.
The incidence rate of colon cancer among women
slowly increased between 1973 and 1985 and has
slowly declined since. The incidence of uterine (corpus
uteri) cancer in females was relatively stable since 1986
with a small decrease in more recent years, ranging
from 25.4 (1997) to 23.3 (2003) cases per 100,000. The
incidence rate of non-Hodgkin's lymphoma has
exhibited a slow increase since 1973.
20 Recent trends in cancer incidence rates among the less prevalent site-specific cancers in females showed
21 increases for melanoma, which ranged from 13.7 (1995) to 16.2 (2001) cases per 100,000 and thyroid
22 cancer, which ranged from 8.9 (1995) to 14.0 (2003) cases per 100,000. Incidence rates decreased for
23 cancers of the ovary, which ranged from 14.7 (1997) to 13.2 (2003) cases per 100,000. (Data not shown.)
Exhibit 5-11. Age-adjusted cancer incidence
rates in the U.S., 1973-2003: Top five cancers in
females of all ages3
'85 '90 '95
Year of diagnosis
Rates are age-adjusted to the 2000
U.S. standard population.
— Breast
Colon and rectum
Corpus uteri
— Lung and bronchus
— Non-Hodgkin's lymphom
Data source: NCI. Surveillance,
Epidemiology, and End Results
(SEER) Database
Indicator Limitations
SEER data cover approximately 26 percent
of the U.S. population, though it is
designed to be representative of the entire
U.S. population.
Incidence data generated from SEER are
updated annually. There may be changes in
the numerator (e.g., revised counts of
newly identified cases) or denominator
(i.e., revised population counts) numbers
that result in small changes in the overall
incidence rates for the same year
depending on when a query is run within
the SEER database. For example, the
SEER database queried in 2005 generating
incidence rates for the year 2000 may
provide different incidence rates than the
database queried in 2004 for the same year
(i.e., 2000).
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5-33
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1 Data Sources
2 Cancer incidence data for this indicator were obtained by querying the National Cancer Institute's (NCI's)
3 Surveillance, Epidemiology, and End Results (SEER) Program database through the Cancer Query
4 Systems (CANQUES) web-based interface (NCI, 2006), available at
5 http://www.seer.cancer.gov/canques/incidence.html.
6 References
7 ACS (American Cancer Society). 2003. Cancer facts and figures, 2003. Accessed October 19, 2005.
8
9 Hankey, B.F., E.J. Feuer, L.X. Clegg, et al. 1999. Cancer surveillance series: interpreting trends in
10 prostate cancer-part I: evidence of the effects of screening in recent prostate cancer incidence, mortality,
11 and survival rates. J. Natl. Cancer Inst. 91:1017-1024.
12
13 Edwards, K.E., M.L. Brown, P.A. Wingo, et al. 2005. Annual report to the nation on the status of cancer,
14 1975-2002, featuring population-based trends in cancer treatment. J. Natl. Cancer Inst. 97(19): 1407-1427.
15
16 NCHS (National Center for Health Statistics). 2006. Deaths: final data 2003. National Vital Statistics
17 Reports 54(13). April 19.
18 NCI (National Cancer Institute). 2006. Surveillance, Epidemiology, and End Results (SEER) Program
19 CANQUES database. SEER registry public use, Nov 2005, Sub (1973-2003). National Cancer Institute,
20 DCCPS, Surveillance Research Program. Released April 2006, based on November 2005 submission.
21 Accessed September 2006.
22 NCI (National Cancer Institute), n.d. Dictionary of cancer terms. Accessed October 7, 2004.
23
24 NTP (National Toxicology Program). 2004. Report on carcinogens. Eleventh ed. U.S. Department of
25 Health and Human Services, Public Health Service. Accessed February 2, 2005.
26
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NDICATOR: Childhood Cancer Incidenc
Exhibit 5-12. Age-adjusted cancer incidence
rates in the U.S., 1973-2003: All cancer sites for
ages 0-19, by race and sex3
2 The term "cancer" is used to characterize diseases in which abnormal cells divide without control. A
3 cancerous cell loses its ability to regulate its own growth, control cell division, and communicate with
4 other cells. The cellular changes caused by cancer cells are complex and occur over a period of time. This
may be accelerated in children. The classification
of cancers in children differs from the
classification used for adult cancers. The
International Classification of Childhood Cancer
(ICCC) classifies childhood cancer based on
tumor morphology rather than, as for adults, the
site of the tumor. If left unchecked, cancer cells
can invade nearby tissues and can spread through
the bloodstream and lymphatic system to other
parts of the body (NCI, 2004).
The causes of childhood cancers are largely
unknown. Only a small percentage of cases can
be explained by a few conditions such as specific
chromosomal/genetic abnormalities (e.g., Down
syndrome) and ionizing radiation exposure (NCI,
2002). Environmental exposures have long been
suspected of increasing the risk of certain
childhood cancers. Researchers continue to
examine environmental influences on childhood
cancer.
This indicator presents incidence rates for
childhood cancers using data collected through
the National Cancer Institute's Surveillance,
Epidemiology, and End Results (SEER) Program.
The SEER Program collects and publishes cancer
incidence and survival data from 14 population-
based cancer registries and three supplemental
registries covering approximately 26 percent of
the U.S. population.
What the Data Show
In general, overall childhood (ages 0-19 years)
cancer incidence for the U.S. has increased
slightly between 1973 and 2003 (Exhibit 5-12),
increasing over time from an age-adjusted
incidence rate of 13.8 per 100,000 in 1973 to a
high of 17.2 per 100,000 in 2002. A slightly
lower rate (15.4 per 100,000) was reported in
2003. Males generally had higher rates than
females, although for some years the reverse was
true. Incidence among black females and males
aRates are age-adjusted to the 2000 U.S.
standard population, age 0-19 years.
Data source: NCI, 2006. Surveillance,
Epidemiology, and End Results (SEER)
Database
Exhibit 5-13. Age-adjusted cancer incidence
rates in the U.S., 1973-2003: Top five cancers
for ages 0-19a
Rates are age-adjusted to the
2000 U.S. standard population,
age 0-19 years.
Data source: NCI. Surveillance,
Epidemiology, and End Results
(SEER) Database
Brain and other nervous
system
Hodg kin's lymphoma
— Leukemia
— Lymphoma
— Non-Hodgkin's lymphoma
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5-35
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1 age 0-19 years was lower compared to white females and males. In 2003, black females and males age 0-
2 19 years had overall incidence rates of 11.8 and 10.3 per 100,000, respectively, compared to white
3 females and males with rates of 14.7 and 18.2 per 100,000 (Exhibit 5-12).
4 Exhibit 5-13 presents the age-adjusted incidence rates for the top five cancers among children 0-19 years
5 of age between 1973 and 2003. In general, there are no clearly identifiable trends among any of the top
6 five cancers over the reported time period. Leukemia continues to be the most frequently diagnosed
7 cancer in children age 0-19 years.
8 Indicator Limitations
9 • Incidence data generated from SEER are updated annually. There may be changes in the
10 numerator (e.g., revised counts of newly identified cases) or denominator (i.e., revised
11 population counts) numbers that result in small changes in the overall incidence rates for the
12 same year depending on when a query is run within the SEER database. For example, the
13 SEER database queried in 2005 generating incidence rates for the year 2000 may provide
14 different incidence rates than the database queried in 2004 for the same year (i.e., 2000).
15 Data Sources
16 Cancer incidence data for this indicator were obtained by querying the National Cancer Institute's (NCI's)
17 Surveillance, Epidemiology, and End Results (SEER) Program database through the Cancer Query
18 Systems (CANQUES) web-based interface (NCI, 2006), available at
19 http: //www .seer, cancer, gov/canque s/incidence .html.
20 References
21 NCI (National Cancer Institute). 2006. Surveillance, Epidemiology, and End Results (SEER) Program
22 CANQUES database. SEER registry public use, Nov 2005, Sub (1973-2003). National Cancer Institute,
23 DCCPS, Surveillance Research Program. Released April 2006, based on November 2005 submission.
24 Accessed 2006.
25 NCI (National Cancer Institute). 2004. Dictionary of cancer terms. Accessed October 7, 2004.
26
27 NCI (National Cancer Institute). 2002. Cancer facts: National Cancer Institute research on childhood
28 cancers. Accessed February 2, 2005.
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INDICATOR: Cardiovascular Disease Prevalence and Mortalit
2 The broad category of cardiovascular disease (CVD) includes any disease involving the heart and blood
3 vessels. Coronary heart disease, cerebrovascular disease (commonly known as stroke), and hypertension
4 are the major cardiovascular diseases (American Heart Association, 2003). In addition to being a major
5 risk factor for heart disease and stroke, hypertension is a commonly diagnosed disease that can also lead
6 to kidney damage and other health problems. Obesity, physical inactivity, and sodium intake are all
7 important risk factors for hypertension (NIH, 2004). Since 1900, cardiovascular disease has been the
8 leading cause of death in the United States every year except 1918 (American Heart Association, 2003)
9 (General Mortality indicator, p. 5-13). The U.S. age-adjusted mortality rate for CVD reached a peak in
10 1950 (CDC, 1999). Between 1950 and 1999, the age-adjusted mortality rate for CVD declined 60 percent.
11 The major risk factors for CVD include tobacco use, high blood pressure, high blood cholesterol,
12 diabetes, physical inactivity, and poor nutrition (CDC, 2004).
13 Environmental factors may also play a role in CVD morbidity and mortality independent of other risk
14 factors. However, susceptible populations such as the elderly and other high-risk populations may be
15 most impacted. For example, chronic exposure to ambient airborne particulate matter has been shown in
16 studies to be associated with increased hospitalizations and mortality among older individuals, largely due
17 to cardiopulmonary and cardiovascular disease (U.S. EPA, 2004). Environmental tobacco smoke (ETS)
18 may also contribute to CVD. Although the smoke to which a nonsmoker is exposed is less concentrated
19 than that inhaled by smokers, research has demonstrated increased cardiovascular-related health risks
20 associated with ETS (State of California, 2005).
21 This indicator presents U.S. adult (age 18 and older) prevalence rates for heart disease (all types),
22 coronary heart disease, stroke, and hypertension; and mortality rates for CVD as a whole as well as
23 coronary heart disease (including myocardial infarction), stroke, and hypertension. CVD prevalence data
24 were compiled between 1997 and 2004 from the National Center for Health Statistics (NCHS) National
Health Interview Survey (NHIS). NHIS is the principal
source of information on the health of the civilian non-
institutionalized population of the United States and
since 1960 has been one of the major data collection
programs of NCHS. CVD prevalence is based on the
number of adults who reported that they had ever been
told by a doctor or other health practitioner that they
had a specified cardiovascular disease. Mortality data
(all ages) were compiled between 1979 and 2002 using
the National Vital Statistics System (NVSS),
maintained by NCHS. The NVSS registers virtually all
deaths and births nationwide with data coverage from
1933 to 2003 and from all 50 States and the District of
Columbia.
Exhibit 5-14. Cardiovascular disease
prevalence in U.S. adults (age 18 and older),
1997-20043
200 ,
§. 150
S.
— 100
1
DC
50'
0
'9
_^_— '
7 '98 '99 '00 '01 '02 '03 '0
Year
"Rates presented are crude rates.
Data source: CDC/NCHS, National Health
Interview Survey
What the Data Show
CVD Prevalence
Among adults 18 years and older, the prevalence of
heart disease and stroke between 1997 and 2004 has
remained essentially the same (Exhibit 5-14). In
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5-37
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1 contrast, the prevalence of hypertension has shown a slow increase from 191.6 cases per 1,000 in 1999 to
2 220.7 cases per 1,000 in 2004.
3 Gender, race, and age differences in CVD prevalence exist. The prevalence of coronary heart disease
4 among males is consistently higher than females (76.6 cases per 1,000 compared with 50.9 cases per
5 1,000 for women in 2004). In contrast, hypertension is more prevalent among women (228.0 cases per
6 1,000 for women compared with 212.8 for men in 2004). Among the racial groups reported, American
7 Indian and Alaska Natives typically had the highest prevalence of coronary heart disease between 1999
8 and 2003. In 2004, however, whites had the highest prevalence of coronary heart disease (67.5 cases per
9 1,000) followed by American Indian and Alaska Natives (58.6 cases per 1,000), blacks or African
10 Americans (44.0 cases per 1,000), and Asians (32.2 cases per 1,000). In 2004, Asians also consistently
11 had the lowest prevalence of stroke (16.7 cases per 1,000) and hypertension (132.2 cases per 1,000)
12 among the racial groups reported. In addition, the Hispanic or Latino population had a consistently lower
13 prevalence of the major CVD-related diseases compared with the non-Hispanic or Latino population from
14 1999-2004, the period for which these data are available. For example, in 2004, prevalence in Hispanics
15 or Latinos was lower than non-Hispanics or Latinos for coronary heart disease (38.9 versus 66.8 cases per
16 1,000, respectively), hypertension (139.3 versus 232.3 cases per 1,000, respectively), and stroke (17.2
17 versus 26.9 cases per 1,000, respectively).(Data not shown.)
18 CVD Mortality
19 In 1998, the national age-adjusted CVD mortality rate
20 (all types) was 352.0 per 100,000 compared to a rate
21 of 541.0 per 100,000 in 1980 (Exhibit 5-15). This
22 decline appears to continue after 1999, with the rate
23 dropping from 349.3 per 100,000 in 1999 to 317.4 per
24 100,000 in 2002. Both coronary heart disease and
25 stroke mortality rates have been declining in the
26 United States. The age-adjusted coronary heart disease
27 mortality rate ranged from 345.2 per 100,000 in 1980
28 to 197.1 per 100,000 in 1998. For stroke mortality the
29 age-adjusted rate ranged from 97.1 per 100,000 in
30 1979 to 59.3 per 100,000 in 1998. The age-adjusted
31 mortality rates for myocardial infarction ranged from
32 157.9 in 1979 to 76 per 100,000 in 1998. The age-
33 adjusted mortality rate (2000 U.S. Standard
34 Population) for coronary heart disease, stroke, and
35 myocardial infarction in 2002 was 170.9, 56.2, and
36 62.1 per 100,000, respectively, compared to 194.6,
37 61.6, and 73.2 per 100,000, respectively, in 1999.
38 Death rates from hypertension remained essentially the
39 same between 1999 and 2002.
Exhibit 5-15. Age-adjusted cardiovascular
disease mortality rates in the U.S., 1979-2002ab
•oo
aDue to differences in the ICD system used for
classifying mortality, data from 1979-1998
should not be directly compared to data from
1999-2002 [ICD-9 codes: 390-434,436-448
(1979-1998); ICD-10 codes: IOO-I78 (1999-
2002)].
"Rates are age-adjusted to the 2000 U.S.
standard population.
Data source: CDC WONDER
40 Both coronary heart disease and stroke mortality have been declining overtime in the 10 EPA Regions
41 (Exhibits 5-16 and 5-17). In 1979, coronary heart disease and stroke age-adjusted mortality rates (2000
42 U.S. Standard Population) ranged from 285.6 (Region 10) to 401.9 (Region 2) per 100,000 and 80.3
43 (Region 2) to 111.4 (Region 4) per 100,000, respectively. In 1998, coronary heart disease and stroke
44 mortality rates ranged 145.6 (Region 8) to 233.2 (Region 2) per 100,000 and 43.2 (Region 2) to 68.5 per
45 (Region 10) 100,000, respectively. The observed decreases in coronary heart disease and stroke mortality
46 also appear to continue in the 1999-2002 period.
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5-38
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1 Differences exist in CVD mortality rates among gender, racial and age groups. For example, in 2002,
2 those age 65 and older had the highest CVD (all types), coronary heart disease, and stroke mortality
3 (2,119.4, 1,135.9, and 393.2 per 100,000, respectively) compared to younger age groups. For the same
4 year, the age-adjusted CVD, coronary heart disease, and stroke mortality rates for those 45-64 years of
5 age were 185.2, 108.5, and 23.8 per 100,000, respectively. Notable differences in CVD (all types) and,
6 specifically, coronary heart disease mortality rates exist between males and females, but not for stroke
7 mortality. Coronary heart disease mortality among males in 2002 was 220.4 per 100,000 compared to
8 133.6 per 100,000 for women. In 2002, black or African American males had the highest CVD mortality
9 rate at 487.5 per 100,000 compared to white males (370.7 per 100,000), black or African American
10 females (363.8 per 100,000) and white females (262.8 per 100,000). (Datanot shown.)
Exhibit 5-16. Age-adjusted coronary heart
disease mortality rates in the U.S. by EPA
Region, 1979-2002ab
450
400
350
& 300
So-
li § 250
ss
200
150
100
50
-R1
-R2
-R3
-R4
-R5
R6
R7
R8
-R9
-R10
-Nat'l
'80
'85
'90
Year
'95
aDue to differences in the ICD
system used for classifying
mortality, data from 1979-1998
should not be directly compared
to data froml 999-2002 [ICD-9
codes: 410-414,429.2 (1979-
1998); ICD-10 codes: I20-I25
(I999-2002)].
"Rates are age-adjusted to the
2000 U.S. standard population.
Data source: CDC WONDER
'00
EPA Regions
Exhibit 5-17. Age-adjusted stroke mortality
in the U.S. by EPA Region, 1979-2002a'b
rates
120
100
80
40
20
-R1
—R2
—R3
—R4
-R5
R6
—R7
R8
-R9
-R10
—Nat'l
'80
'85
'90
Year
'95
aDue to differences in the ICD
system used for classifying
mortality, data from 1979-1998
should not be directly compared
to data from 1999-2002 [ICD-9
codes: 430-434,436-438 (1979-
1998); ICD-10 codes: I60-I69
(1999-2002)].
"Rates are age-adjusted to the
2000 U.S. standard population.
Data source: CDC WONDER
'00
EPA Regions
11 Indicator Limitations
12
13
14
15
16
17
Prevalence data reported in the NHIS are based on self-reported responses to specific
questions pertaining to CVD-related illnesses, and are subject to the biases associated with
self-reported data. Self-reported data may underestimate the disease prevalence being
measured if, for whatever reason, the respondent is not fully aware of his/her condition.
All prevalence data are based on crude rates and are not age-adjusted, as CDC did not report
age-adjusted data prior to 2002 in the data sources used for this indicator. Therefore, the
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5-39
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1 reported disease prevalence rates across time or within different race and gender subgroups
2 may not reflect differences in the age distribution of the populations being compared.
3 • For one or more years for which data are presented, coronary heart disease and stroke
4 prevalence rates presented for Native American and Alaskan Natives have a relative standard
5 error of greater than 30 percent. In addition, stroke prevalence rates for one or more years for
6 which data are presented for Asians have a relative standard error of greater than 30 percent.
7 As such, these rates should be used with caution as they do not meet the standard of
8 reliability or precision.
9 • CVD mortality rates are based on underlying cause-of-death as entered on a death certificate
10 by a physician. Some individuals may have had competing causes of death. "When more than
11 one cause or condition is entered by the physician, the underlying cause is determined by the
12 sequence of conditions on the certificate, provisions of the ICD [International Classification
13 of Diseases], and associated selection rules and modifications" (CDC, n.d.). Consequently,
14 some misclassification of reported mortality might occur in individuals with competing
15 causes of death, as well as the possible underreporting of CVD as the cause of death.
16 • CVD mortality rates reported previously for specified years may differ because new age-
17 adjusted rates reflect the 2000 standard census population whereas earlier age-adjusted rates
18 are based on different (e.g., 1990) standard population projections.
19 • For some of the reported years, if the user selects a CDC WONDER query for the United
20 States with data grouped by state, or selects a WONDER query for a specific state, CDC
21 WONDER reports state population figures that do not add up to the national population
22 reported by CDC WONDER. This is because the two different sets of populations come from
23 different U.S. Census population estimates. (For all other years, these two sets of population
24 data are the same.)
25 • The International Classification of Diseases 9th Revision (ICD-9) codes were used to specify
26 underlying cause of death for years 1979-1998. Beginning in 1999, cause of death is specified
27 with the International Classification of Diseases 10th Revision (ICD-10) codes. The two
28 revisions differ substantially, and to prevent confusion about the significance of any specific
29 disease code, data queries are separate.
30 Data Sources
31 CVD prevalence data were obtained from annual reports published by CDC's National Center for Health
32 Statistics (NCHS, 1999-2006), which summarize health statistics compiled from the center's National
33 Health Interview Survey (http://www.cdc.gov/nchs/products/pubs/pubd/series/sr 10/ser 10 .htm). CVD
34 mortality statistics were obtained from CDC's "compressed mortality" database, accessed through CDC
35 WONDER (CDC, 2006) (http://wonder.cdc.gov/mortSQL.html). EPA Regional mortality statistics were
36 generated by combining and age-adjusting state-by-state totals for each EPA Region using data from
37 CDC WONDER.
38 References
39 American Heart Association. 2003. Heart disease and stroke statistics—2004 update. Dallas, TX.
40 CDC (Centers for Disease Control and Prevention). 2006. CDC Wide-ranging OnLine Data for
41 Epidemiologic Research (WONDER). Compressed mortality file, underlying cause of death. 1999-2003
42 (with ICD 10 codes) and 1979-1998 (with ICD 9 codes). Accessed 2006.
43
SCIENCE ADVISORY BOARD REVIEW DRAFT: Please do not distribute, cite, or quote. 5-40
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1 CDC (Centers for Disease Control and Prevention). 2004. The burden of chronic diseases and their risk
2 factors—national and state perspectives. Accessed February 2, 2005.
3
4 CDC (Centers for Disease Control and Prevention). 1999. Decline in deaths from heart disease and stroke,
5 United States, 1990-1999. Washington, DC.
6 CDC (Centers for Disease Control and Prevention), n.d. CDC WONDER: Help page for compressed
7 mortality file,
8 U.S. EPA. 2004. Air quality criteria for particulate matter. Volumes I (EPA/600/P-99/002aF) and II
9 (EPA/600/P-99/002bF). National Center for Environmental Assessment-RTP Office, Office of Research
10 and Development.
11 NCHS (National Center for Health Statistics). 2006. Summary health statistics for U.S. adults: National
12 Health Interview Survey, 2004. Vital Health Stat 10(228).
13
14 NCHS (National Center for Health Statistics). 2005. Summary health statistics for U.S. adults: National
15 Health Interview Survey, 2003. Vital Health Stat 10(225).
16
17 NCHS (National Center for Health Statistics). 2004. Summary health statistics for U.S. adults: National
18 Health Interview Survey, 2002. Vital Health Stat 10(222).
19
20 NCHS (National Center for Health Statistics). 2003. Summary health statistics for U.S. adults: National
21 Health Interview Survey, 2001. Vital Health Stat 10(218).
22
23 NCHS (National Center for Health Statistics). 2002. Summary health statistics for U.S. adults: National
24 Health Interview Survey, 2000. Vital Health Stat 10(215).
25
26 NCHS (National Center for Health Statistics). 2001. Summary health statistics for U.S. adults: National
27 Health Interview Survey, 1999. Vital Health Stat 10(212).
2 8
29 NCHS (National Center for Health Statistics). 2000. Summary health statistics for U.S. adults: National
30 Health Interview Survey, 1998. Vital Health Stat 10(209).
31
32 NCHS (National Center for Health Statistics). 1999. Summary health statistics for U.S. adults: National
33 Health Interview Survey, 1997. Vital Health Stat 10(205).
34
35 NIH (National Institute of Health). 2004. NIH news: the increasing number of adults with high blood
36 pressure. Accessed September 11, 2005.
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1 State of California. 2005. Proposed identification of environmental tobacco smoke as a toxic air
2 contaminant. Part B: health effects assessment for environmental tobacco smoke. As approved by the
3 Scientific Review Panel on June 24, 2005. California Environmental Protection Agency, Office of
4 Environmental Health Hazard Assessment,
SCIENCE ADVISORY BOARD REVIEW DRAFT: Please do not distribute, cite, or quote. 5-42
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NDICATOR: Chronic Obstructive Pulmonary Disease Prevalence and Mortality
2 Chronic obstructive pulmonary disease (COPD), sometimes referred to as chronic lung disease, is a
3 disease that damages lung tissue or restricts airflow through the bronchioles and bronchi (NHLBI, 2003).
4 Chronic bronchitis and emphysema are the most frequently occurring COPDs. Smoking is the most
5 common cause of COPD, including cigarette, pipe, and cigars (NHLBI, 2003). Other factors involved in
6 the development and progression of COPD include, asthma, heavy exposure to air pollutants in the
7 ambient air and workplace environment, genetic factors, and respiratory infections (CDC, 2005;
8 American Lung Association, 2004).
9 Environmental tobacco smoke (ETS) may also increase the risk of developing COPD. The effect of
10 chronic ETS exposure alone on pulmonary function in otherwise healthy adults is likely to be small.
11 However, in combination with other exposures (e.g., prior smoking history, exposure to occupational
12 irritants or ambient air pollutants), ETS exposure could contribute to chronic respiratory impairment.
13 Children are especially sensitive to the respiratory effects of ETS exposure (State of California, 2005).
14 This indicator presents U.S. adult (age 18 and older) prevalence rates for chronic bronchitis and
15 emphysema and mortality rates for COPD as a whole and for chronic bronchitis and emphysema. COPD
16 prevalence data were compiled from 1997 to 2004 from the National Center for Health Statistic's (NCHS)
17 National Health Interview Survey (NHIS). NHIS is the principal source of information on the health of
18 the civilian non-institutionalized population of the United States and since 1960 has been one of the major
19 data collection programs of NCHS. COPD prevalence is based on the number of adults who reported that
20 they had ever been told by a doctor or other health practitioner that they had a specified chronic bronchitis
21 or emphysema. Mortality data (all ages) were compiled between 1979 and 2002 using the National Vital
22 Statistics System (NVSS), maintained by NCHS. The NVSS registers virtually all deaths and births
23 nationwide with data coverage from 1933 to 2003 and from all 50 States and the District of Columbia.
24 What the Data Show
25 COPD Prevalence
26 Exhibit 5-18 presents the prevalence of chronic bronchitis (Panel A) and emphysema (Panel B) from 1999
27 to 2004. The reported total prevalence of chronic bronchitis in U.S. adults over the age of 18 years ranged
28 from a low of 40 (2003) to a high of 55 (2001) cases per 1,000. The reported total prevalence of
Exhibit 5-18. Chronic bronchitis and emphysema prevalence in U.S. adults (age 18 and older) by
race, 1999-20043
A. Chronic bronchitis
B. Emphysema
50
8 4Q
te 30
Q.
€ 20
DC
10
'99
'00
'01
'02
'03
'04 '99
'00
'02
'03
'04
Year
"Rates presented are
crude rates.
Data source: CDC/NCHS
National Health Interview
Survey
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5-43
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1 emphysema in U.S. adults during the same time period ranged from 14 (1999) to 17 (1997) cases per
2 1,000. A small increase in prevalence of chronic bronchitis can be seen from 1999 to 2001, with an
3 overall decline from 2002 to 2004. The reported total prevalence of emphysema in U.S. adults during the
4 same time period ranged from 14 (1999) to 17 (2004) cases per 1,000. No notable change in the
5 prevalence for emphysema was evident during this time period. Exhibit 5-18 also displays chronic
6 bronchitis and emphysema prevalence by race. Chronic bronchitis prevalence was higher among white
7 (designated as "white only") adults compared to black ("black or African American only") adults during
8 1999 (46 versus 36 cases per 1,000, respectively) and 2000 (49 versus 40 cases per 1,000, respectively).
9 The same racial difference in prevalence exists for emphysema, but the difference remains consistent
10 throughout the entire time period.
11 In addition, the Hispanic or Latino population had a consistently lower prevalence of chronic bronchitis
12 and emphysema diseases compared with the non-Hispanic or Latino population from 1999-2004, the
13 period for which these data are available. For example, in 2004, prevalence in Hispanics or Latinos was
14 lower than non-Hispanics or Latinos for chronic bronchitis (44 compared to 25 cases per 1,000,
15 respectively) and emphysema (18 compared to 6 cases per 1,000, respectively). (Data not shown.)
16 Gender differences are also seen. In 2004, females had about twice the reported prevalence of chronic
17 bronchitis than males (56 versus 27 cases per 1,000 respectively), a consistently observed difference
18 between 1997 and 2004. Unlike with chronic bronchitis, the prevalence rates for emphysema have been
19 consistently higher in males than in females. (Data not shown).
Exhibit 5-19. Chronic obstructive pulmonary
disease mortality rates in the U.S. by EPA
Region, 1979-2002ab
'00
aDue to differences in the ICD
system used for classifying
mortality, data from 1979-1998
should not be directly compared
to data froml 999-2002 [ICD-9
codes: 490-494, 496(1979-
1998); ICD-10 codes: J40-J47
(1999-2002)].
bRates are age-adjusted to the
2000 U.S. standard population.
Data source: CDC WONDER
EPA Regions
COPD Mortality
In 2003, COPD continues to be the fourth leading cause
of mortality accounting for 126,382 deaths (General
Mortality indicator, p.5-13). The age-adjusted mortality
rate for COPD as a whole has increased over time, with
rates ranging from 25.5 per 100,000 in 1979 to 41.8 per
100,000 in 1998. From 1999-2002,rates held steadier,
ranging from 45.4 per 100,000 in 1999 to 43.5 per
100,000 in 2002. Mortality rates for emphysema (1.9
and 1.1 per 100,000 1979 and 1998, respectively and
0.4 and 0.3 per 100,000 for 1999 and 2003,
respectively) and chronic bronchitis (6.9 and 6.5 per
100,000 1979 and 1998, respectively and 6.5 and 5.1
per 100,000 1999 and 2003, respectively) have not
changed substantially during this same time period
(data not shown).
Exhibit 5-19 presents the overall COPD mortality rates
in the U.S. and the 10 EPA Regions for the time
periods 1979-1998 and 1999-2002. The age-adjusted
COPD mortality rates have been increasing in each of
the 10 Regions from 1979 to 1998. The rates ranged
from 22.2 (Region 2) to 31.2 (Region 8) per 100,000 in
1979 and 33.5 (Region 2) to 47.9 (Region 8) per
100,000 in 1998.
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5-44
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1 COPD age-adjusted mortality rates have slowly been declining for males over time with rates of 58.7,
2 55.8, 54.0, and 53.5 per 100,000 in 1999, 2000, 2001, and 2002, respectively. For females, the rates are
3 lower than males and have been stable over the above four years (37.7, 37.4, 37.6, and 37.4 per 100,000
4 in 1999, 2000, 2001, and 2002, respectively). The COPD age-adjusted mortality rate is higher among
5 whites (45.4 per 100,000 in 2002) compared to blacks or African Americans (31.2 per 100,000 in 2002).
6 COPD mortality rate increases with age with the 2002 rate of 0.4, 1.2, 21.9, and 300.6 per 100,000 for
7 those age 0-14 years, 15-44 years, 45-64 years and 65 years and older, respectively.
8 Indicator Limitations
9 • Prevalence data presented in the NHIS are based on self-reported responses to specific
10 questions pertaining to COPD-related illnesses, and are subject to the biases associated with
11 self-reported data. Self-reported data may underestimate the disease prevalence being
12 measured if, for whatever reason, the respondent is not fully aware of his/her condition.
13 • All prevalence data are based on crude rates and are not age-adjusted, as CDC did not report
14 age-adjusted data prior to 2002 in the data sources used for this indicator. Therefore, the
15 reported disease prevalence rates across time or within different race and gender subgroups
16 may not reflect differences in the age distribution of the populations being compared.
17 • COPD mortality rates are based on underlying cause-of-death as entered on a death certificate
18 by a physician. Some individuals may have had competing causes of death. "When more than
19 one cause or condition is entered by the physician, the underlying cause is determined by the
20 sequence of conditions on the certificate, provisions of the ICD [International Classification
21 of Diseases], and associated selection rules and modifications" (CDC, n.d.). Consequently,
22 some misclassification of reported mortality might occur in individuals with competing
23 causes of death, as well as the possible underreporting of COPD as the cause of death.
24 • For some of the reported years, if the user selects a CDC WONDER query for the United
25 States with data grouped by state, or selects a WONDER query for a specific state, CDC
26 WONDER reports state population figures that do not add up to the national population
27 reported by CDC WONDER. This is because the two different sets of populations come from
28 different U.S. Census population estimates. (For all other years, these two sets of population
29 data are the same.)
30 • The International Classification of Diseases 9th Revision (ICD-9) codes were used to specify
31 underlying cause of death for years 1979-1998. Beginning in 1999, cause of death is specified
32 with the International Classification of Diseases 10th Revision (ICD-10) codes. The two
33 revisions differ substantially, and to prevent confusion about the significance of any specific
34 disease code, data queries are separate.
35 Data Sources
36 COPD prevalence data were obtained from annual reports published by CDC's National Center for Health
37 Statistics (NCHS, 1997-2006), which summarize health statistics compiled from the center's National
38 Health Interview Survey (http://www.cdc. gov/nchs/products/pubs/pubd/series/sr 10/ser 10 .htm). Mortality
39 statistics were obtained from CDC's "compressed mortality" database, accessed through CDC WONDER
40 (CDC, 2006) (http://wonder.cdc.gov/mortSOL.html). EPA Regional mortality statistics were generated by
41 combining and age-adjusting state-by-state totals for each EPA Region using data from CDC WONDER.
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1 References
2 American Lung Association. 2004. Chronic obstructive pulmonary disease (COPD) fact sheet. Accessed
3 February 7, 2005.
4 CDC (Centers for Disease Control and Prevention). 2006. CDC Wide-ranging OnLine Data for
5 Epidemiologic Research (WONDER). Compressed mortality file, underlying cause of death. 1999-2003
6 (with ICD 10 codes) and 1979-1998 (with ICD 9 codes). Accessed 2006.
7
8 CDC (Centers for Disease Control and Prevention). 2005. Facts about chronic obstructive pulmonary
9 disease (COPD). Accessed February 7, 2005.
10 CDC (Centers for Disease Control and Prevention), n.d. CDC WONDER: Help page for compressed
11 mortality file,
12 NCHS (National Center for Health Statistics). 2006. Summary health statistics for U.S. adults: National
13 Health Interview Survey, 2004. Vital Health Stat 10(228).
14
15 NCHS (National Center for Health Statistics). 2005. Summary health statistics for U.S. adults: National
16 Health Interview Survey, 2003. Vital Health Stat 10(225).
17
18 NCHS (National Center for Health Statistics). 2004. Summary health statistics for U.S. adults: National
19 Health Interview Survey, 2002. Vital Health Stat 10(222).
20
21 NCHS (National Center for Health Statistics). 2003. Summary health statistics for U.S. adults: National
22 Health Interview Survey, 2001. Vital Health Stat 10(218).
23
24 NCHS (National Center for Health Statistics). 2002. Summary health statistics for U.S. adults: National
25 Health Interview Survey, 2000. Vital Health Stat 10(215).
26
27 NCHS (National Center for Health Statistics). 2001. Summary health statistics for U.S. adults: National
28 Health Interview Survey, 1999. Vital Health Stat 10(212).
29
30 NCHS (National Center for Health Statistics). 2000. Summary health statistics for U.S. adults: National
31 Health Interview Survey, 1998. Vital Health Stat 10(209).
32
33 NCHS (National Center for Health Statistics). 1999. Summary health statistics for U.S. adults: National
34 Health Interview Survey, 1997. Vital Health Stat 10(205).
35
SCIENCE ADVISORY BOARD REVIEW DRAFT: Please do not distribute, cite, or quote. 5-46
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1 NHLBI (National Heart, Lung, and Blood Institute). 2003. Chronic obstructive pulmonary disease fact
2 sheet. NIH publication No. 03-5229. Bethesda, MD: U.S. Department of Health and Human Services.
3 Accessed October 29, 2004.
4 State of California. 2005. Proposed identification of environmental tobacco smoke as atoxic air
5 contaminant. Part B: health effects assessment for environmental tobacco smoke. As approved by the
6 Scientific Review Panel on June 24, 2005. California Environmental Protection Agency., Office of
7 Environmental Health Hazard Assessment,
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NDICATOR: Asthma Prevalei
2 Asthma is a chronic respiratory disease characterized by inflammation of the airways and lungs. During
3 an asthma attack, the airways that carry air to the lungs are constricted, and as a result, less air is able to
4 flow in and out of the lungs (NHLBI, 2004). Asthma attacks can cause a multitude of symptoms ranging
5 in severity from mild to life-threatening. These symptoms include wheezing, breathlessness, chest
6 tightness, and coughing (NHLBI, 2004). Currently, there is no cure for asthma; however, people who
7 have asthma can still lead quality, productive lives if they control their asthma. Taking medication and
8 avoiding contact with environmental "triggers" can control asthma.
9 A family history of asthma contributes to susceptibility, but mostly, it is unknown what causes the
10 development of asthma. Environmental exposures such as environmental tobacco smoke, dust mites,
11 cockroach allergen, outdoor air pollution, pets, and mold are considered important triggers of an asthma
12 attack (CDC, 2003, 2004).
13 Statistics for lifetime diagnosis prevalence, current asthma prevalence, and asthma attack prevalence are
14 based on national estimates from the National Health Interview Survey (NHIS). NHIS is the principal
15 source of information on the health of the civilian non-institutionalized population of the United States
16 and since 1960 has been one of the major data collection programs of NCHS. For this indicator, lifetime
17 asthma diagnosis is defined as the number of adults/children who reported that they had ever been told by
18 a doctor or other health practitioner that they had asthma. To determine current asthma prevalence,
19 adults/children who had been told that they had asthma were asked whether they still have asthma.
20 Asthma attack prevalence is based on the number of adults/children who reported an asthma episode or
21 attack in the past 12 months.
22 What the Data Show
23 From 2002 to 2004,approximately 7 percent of the U.S. population reported that they currently have
24 asthma (NCHS, 2006a). Reported asthma rates are highest in the child and adolescent population.
25 Adult Asthma
26 In adults, asthma prevalence rates (i.e., lifetime diagnosis) generally increased from 1997 to 2001 (Exhibit
27 5-20, panel B). The prevalence rates range from a low of 85 cases per 1,000 in 1999 to a high of 109
28 cases per 1,000 in 2001. Asthma was consistently higher among adult females than males, with a range of
29 98 (1999) and 123 (2001) cases per 1,000 in females and 71 (1999) and 94 (2001) cases per 1,000 in
30 males. The asthma prevalence rate also consistently decreases in older populations. In 2004, the asthma
31 prevalence rate was 99 (ages 18-44 years), 100 (ages 45-64), 103 (ages 65-74 years), and 73 (ages 75+
32 years) cases per 1,000 (data not shown).
33 Exhibit 5-21 compares asthma rates across racial and ethnic groups for the 2002-2004 time period. As
34 shown in Panel A, the lifetime asthma diagnosis in adults was highest among American Indian/Alaska
35 Natives (142 cases per 1,000), followed by black or African Americans (112 cases per 1,000), whites (100
36 cases per 1,000), and lowest among Asians (72 cases per 1,000). This same general pattern is seen for
37 current asthma and asthma attack prevalence. Panel B shows that Hispanics or Latinos had lower rates
38 across all three asthma prevalence categories compared to non-Hispanic whites and non-Hispanic blacks.
39 For lifetime asthma diagnosis, 76 cases per 1,000 were reported in Hispanics or Latinos, 105 cases per
40 1,000 in non-Hispanic whites, and 111 cases per 1,000 in non-Hispanic blacks.
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Exhibit 5-20. Estimated lifetime asthma diagnosis prevalence in children and adults in the U.S.,
1997-2004"b
A. Children (0-17 years)
B. Adults (18 years and older)
lifetime asthma diagnosis is determined
by asking survey participants if they
were "ever" told they had asthma.
bRates presented are crude rates.
Data source: CDC/NCHS, National
Health Interview Survey
'97 '98 '99 '00 '01 '02 '03 '04 '97
'99 '00 '01 '02 '03 '04
Year
Exhibit 5-21. Asthma prevalence in the U.S. by race and Hispanic origin, 2002-2004
A. Asthma prevalence by race
200
160
§
Lifetime asthma diagnosis
Current asthma prevalence
Children
(0-17 years)
Adults
(18+ years)
Children
(0-17 years)
Adults
(18+years)
Asthma attack presence
Children
(0-17 years)
Adults
(18+years)
All groups
White
Black
American Indian/
Alaska Native
Asian
200
160
120
80
40
B. Asthma prevalence by Hispanic origin
Lifetime asthma diagnosis
JJiii
Children
(0-1 7 years)
Adults
(18+ years)
Current asthma prevalence
Asthma attack prevalence
Children
(0-17 years)
Adults
(18+ years)
Children
(0-17 years)
Adults
(18+ years)
All groups
Hispanic
Non-Hispanic white
Non-Hispanic black
'Lifetime asthma diagnosis is determined by asking survey participants if they were "ever" told that they had asthma.
bCurrent asthma prevalence is determined by asking if the survey participant still has asthma.
cAsthma attack prevalence is determined by asking if the survey participant has had an asthma attack within the past 12 months.
Data source: CDC/NHIS, National Health Interview Survey
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5-49
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1 Childhood Asthma
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
In 2004, approximately nine million children within
the United States (age 0-17 years) were reported as
ever having a diagnosis of asthma and nearly 4 million
reported experiencing an asthma episode or attack
during the previous 12 months. As shown in Exhibit 5-
22, asthma prevalence rates increased approximately 4
percent per year between 1980 and 1996. Rates in
subsequent years (1997-2004), reported in three
categories, show no sharp upward or downward
change. Lifetime asthma diagnosis rates range from a
low of 108 cases per 1,000 in 1999 to a high of 127
cases per 1,000 in 2001. Since tracking began in 2001,
current asthma prevalence has ranged from
approximately 83.4 cases per 1,000 (2002) to 87 cases
per 1,000 (2001). Asthma attack prevalence rates show
a slight increase from 52.7 per 1,000 in 1999 to 57.7
cases per 1,000 in 2002; however, a slight decrease
(54.6 and 54.4 cases per 1,000) was observed for 2003
and 2004. Male children consistently had higher rates
of asthma prevalence than female children (Exhibit 5-
20, panel A).
Exhibit 5-22. Asthma prevalence in U.S.
children (0-17 years), 1980-2004"
aDue to changes in NHIS questions in 1997, asthma prevalence data
collected from 1980-1996 are not directly comparable to the data
collected from 1997-2004.
''Lifetime asthma diagnosis is determined by asking survey
participants if they were "ever" told their child has asthma.
"Current asthma prevalence is determined by asking if the child still
has asthma.
"Asthma attack prevalence is determined by asking if the child has
had an asthma attack within the past 12 months.
Data source: Adapated from Akinbami and Schoendorf, 2002. Data
from CDC/NCHS National Health Interview Survey (NHIS).
The overall pattern of asthma prevalence across races
in children during 2002-2004 is similar to that seen in
adults (Exhibit 5-21). One notable exception is that
asthma prevalence in black or African American
children was higher than asthma prevalence in
American Indian/Alaska Native children, the reverse of what was observed in the adult population. For
example, reported lifetime asthma diagnosis was highest among black or African American children (173
cases per 1,000), followed by American Indian/Alaska Natives (153 cases per 1,000), whites (112 cases
per 1,000), and lowest among Asians (78 cases per 1,000). Hispanic children had a lower asthma
prevalence rates for all three categories compared to non-Hispanic white and non-Hispanic black children.
33 Indicator Limitations
34
35
36
37
38
39
40
41
42
The National Health Interview Survey (NHIS) questionnaire underwent major changes in
1997, and the data presented focus on surveys conducted from 1997 to the most currently
available release (2004). The redesigned NHIS is different in content, format, and mode of
data collection from earlier versions of the survey. Due to changes in methodology,
comparisons between 1997-2004 NHIS estimates and pre-1997 NHIS data may not be valid.
Prevalence data reported in the NHIS are based on self-reported responses to specific
questions pertaining to airway-related illnesses, and are subject to the biases associated with
self-reported data. Self-reported data may underestimate the disease prevalence being
measured if, for whatever reason, the respondent is not fully aware of his/her condition.
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5-50
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1 Data Sources
2 Asthma prevalence data were obtained from annual reports published by CDC's National Center for
3 Health Statistics (NCHS, 1999; 2000; 2001; 2002a,b; 2003a,b,c,d; 2004a,b; 2005a,b; 2006a,b,c), which
4 summarize health statistics compiled from the center's National Health Interview Survey (NHIS)
5 (http ://www.cdc. gov/nchs/products/pubs/pubd/series/sr 10/ser 10 .htm). Race and ethnicity data were
6 obtained from CDC's online "Health Data for All Ages" (NCHS, 2006a)
7 (http ://www.cdc. gov/nchs/health_data_for_all_ages .htm). The data used by CDC to create the asthma
8 tables in Health Data for All Ages originate from the NHIS. The pre-1997 data also originate from NHIS,
9 as compiled by NCHS in Akinbami and Schoendorf (2002).
10 References
11 Akinbami and Schoendorf. 2002. Trends in childhood asthma: prevalence, health care utilization, and
12 mortality. Pediatrics. 110:2 (Pt 1):315-22
13 CDC (Centers for Disease Control and Prevention). 2003. Basic facts about asthma. Accessed February 3,
14 2005.
15 CDC (Center for Disease Control and Prevention). 2004. Asthma's impact on children and adolescents.
16 Accessed November 22, 2004.
17 NCHS (National Center for Health Statistics). 2006a. Health data for all ages. Accessed 2006.
18
19 NCHS (National Center for Health Statistics). 2006b. Summary health statistics for U.S. adults: National
20 Health Interview Survey, 2004. Vital Health Stat 10(228). See Table 3 and Table 4.
21
22 NCHS (National Center for Health Statistics). 2006c. Summary health statistics for U.S. children:
23 National Health Interview Survey, 2004. Vital Health Stat 10(227). See Table 1 and Appendix III.
24
25 NCHS (National Center for Health Statistics). 2005a. Summary health statistics for U.S. adults: National
26 Health Interview Survey, 2003. Vital Health Stat 10(225). See Table 3 and Table 4.
27
28 NCHS (National Center for Health Statistics). 2005b. Summary health statistics for U.S. children:
29 National Health Interview Survey, 2003. Vital Health Stat 10(223). See Table 1 and Appendix III.
30
31 NCHS (National Center for Health Statistics). 2004a. Summary health statistics for U.S. adults: National
32 Health Interview Survey, 2002. Vital Health Stat 10(222). See Table 3 and Table 4.
33
34 NCHS (National Center for Health Statistics). 2004b. Summary health statistics for U.S. children:
35 National Health Interview Survey, 2002. Vital Health Stat 10(221). See Table 1 and Appendix III.
36
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1 NCHS (National Center for Health Statistics). 2003a. Summary health statistics for U.S. adults: National
2 Health Interview Survey, 2001. Vital Health Stat 10(218). See Table 3 and Table 4.
3
4 NCHS (National Center for Health Statistics). 2003b. Summary health statistics for U.S. children:
5 National Health Interview Survey, 2001. Vital Health Stat 10(216). See Table 1 and Appendix III.
6
7 NCHS (National Center for Health Statistics). 2003c. Summary health statistics for U.S. children:
8 National Health Interview Survey, 2000. Vital Health Stat 10(213). See Table 1 and Appendix III.
9
10 NCHS (National Center for Health Statistics). 2003d. Summary health statistics for U.S. children:
11 National Health Interview Survey, 1999. Vital Health Stat 10(210). See Table 1 and Appendix III.
12
13 NCHS (National Center for Health Statistics). 2002a. Summary health statistics for U.S. adults: National
14 Health Interview Survey, 2000. Vital Health Stat 10(215). See Table 3 and Table 4.
15
16 NCHS (National Center for Health Statistics). 2002b. Summary health statistics for U.S. children:
17 National Health Interview Survey, 1998. Vital Health Stat 10(208). See Table 1 and Appendix III.
18
19 NCHS (National Center for Health Statistics). 2002c. Summary health statistics for U.S. children:
20 National Health Interview Survey, 1997. Vital Health Stat 10(203). See Table 1 and Appendix III.
21
22 NCHS (National Center for Health Statistics). 2001. Summary health statistics for U.S. adults: National
23 Health Interview Survey, 1999. Vital Health Stat 10(212). See Table 3 and Table 4.
24
25 NCHS (National Center for Health Statistics). 2000. Summary health statistics for U.S. adults: National
26 Health Interview Survey, 1998. Vital Health Stat 10(209). See Table 3 and Table 4.
27
28 NCHS (National Center for Health Statistics). 1999. Summary health statistics for U.S. adults: National
29 Health Interview Survey, 1997. Vital Health Stat 10(205). See Table 3 and Table 4.
30
31 NHLBI (National Heart, Lung, and Blood Institute). 2004. Diseases and conditions index. Accessed
32 November 12, 2004.
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INDICATOR:
Conditions
Infectious Diseases Associated with Environmental Exposures or
3 Infectious diseases are human illnesses caused by viruses, bacteria, parasites, fungi and other microbes.
4 They may be spread by direct contact with an infected person or animal, by ingesting contaminated food
5 or water, by insects like mosquitos or ticks (disease vectors), or by contact with contaminated
6 surroundings like animal droppings or contaminated air. Demographic and environmental factors such as
7 population growth, increased urbanization, and alteration of habitats of disease-carrying insects and
8 animals (e.g., irrigation, deforestation) may promote the spread of infectious diseases (CDC, 1998a). The
9 three broad infectious disease categories included here are those whose appearance and spread may be
10 influenced to some extent by environmental conditions and change. They include gastrointestinal (GI)
11 disease, arthropod-borne disease, and legionellosis.
12 Gastrointestinal (GI) Diseases
13 Eight notifiable GI diseases caused by microorganisms are discussed below including: cholera,
14 cryptosporidiosis, Escherichia coll (E. Coli) O157:H7, giardiasis, Hepatitis A, salmonellosis, shigellosis,
15 and typhoid fever. The major environmental source of gastrointestinal illness is water or food that is
16 contaminated with pathogenic microorganisms. The primary means of transmission for these eight
17 diseases is through ingestion of contaminated food/water or through contact and accidental ingestion of
18 fecal matter (CDC, 2005a).
19 Arthropod-borne Diseases
20 Three arthropod-borne diseases are included: Lyme disease (transmission ofBorrelia burgdorferi by
21 ticks), Rocky Mountain spotted fever (transmission ofRickettsia rickettsii by ticks), and West Nile virus
22 (transmitted by mosquitoes). Certain ticks and mosquitoes (arthropods) can carry bacteria and viruses that
23 cause disease in humans. The arthropods acquire the bacteria or viruses when they bite an infected
24 mammal or bird. Some studies indicate that spread of vector-borne disease may be influenced by land use
25 and/or other environmental change (CDC, 2004). In recent years, both Lyme disease and West Nile virus
26 have spread across the United States (CDC, 1993, 2000, 2004). Surveillance for Lyme disease was
27 initiated by the Centers for Disease Control (CDC) in 1982 (CDC, 1993).
28 Legionellosis
29 Legionellosis or Legionnaires' disease is a serious and sometimes fatal form of pneumonia. It is caused
30 by legionella bacteria, which are found naturally in the environment and thrive in warm water and warm
31 damp places. They are commonly found in lakes, rivers, creeks, hot springs and other bodies of water.
32 This bacterium has been associated with outbreaks in the U.S. linked to poorly maintained artificial water
33 systems (e.g., air conditioning and industrial cooling systems) and air ventilation systems. Infection
34 results from inhalation of contaminated water sprays or mists (CDC, 2003a).
35 This indicator reflects occurrence of the aforementioned notifiable diseases as reported by health
36 departments to the National Notifiable Diseases Surveillance System. A notifiable disease is one for
37 which regular, frequent, and timely information regarding individual cases is considered necessary for the
38 prevention and control of the disease (CDC, 2005b). Data are collected by all 50 states, five territories,
39 New York City, and the District of Columbia, based on a list of recommended Nationally Notifiable
40 Infectious Diseases, and compiled nationally. The temporal coverage of the data varies by disease.
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1 What the Data Show
Gastrointestinal Diseases
3
4
5
6
7
8
9
10
11
12
13
14
Exhibits 5-23 and 5-24 present the number of reported cases for each of the eight notifiable GI diseases
from 1995-2004. In comparison to the other GI diseases, the number of newly identified cholera cases
reported each year is low. From 1995 to 2004, just 73 laboratory-confirmed cases of cholera were
reported to CDC with only five cases being reported in 2004, the most current reporting year. Of these 73
total cases, 48 (66 percent) were acquired outside the United States. The number of newly identified cases
of typhoid fever was relatively stable from 1995 to 2004 ranging between a low of 321cases in 2002 and a
high of 396 cases in 1996. In 2004, 322 cases of typhoid fever were reported. Hepatitis A has continued to
decline, with 31,582 cases reported in 1995 compared to 5,683 cases in 2004. No notable changes in the
number of cases were revealed for cryptosporidiosis, E. Coll O157:H7, giardiasis (only 3 years of
reporting data available), salmonellosis, and shigellosis, but under-reporting has probably occurred
because of milder cases not being diagnosed or reported.
Exhibit 5-23. Number of reported cases of gastrointestinal diseases in the U.S., 1995-2004 (part 1)
5,000
'97 '98 '99 '00 '01 '02 '03 '04
'95 '96 '97 '98 '99 '00 '01 '02 '03 '04
'95 '96 '97 '98 '99 '00 '01 '02 '03 '04
Year
aCryptosporidiosis was not on CDC's list of nationally notifiable infectious diseases prior to 1997.
Data source: CDC, Summary of Notifiable Diseases
Exhibit 5-24. Number of reported cases of gastrointestinal diseases in the U.S., 1995-2004 (part 2)
50,000
f 20,000
10,000
aGiardiasis was not on CDC's list of nationally notifiable infectious diseases prior to 2002.
Data source: CDC, Summary of Notifiable Diseases
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1 Arthopod-borne Diseases
2
3
4
5
6
7
8
9
10
11
Exhibit 5-25 presents the number of reported cases for three arthropod-borne diseases. Lyme disease is
the most commonly reported arthropod-borne disease in the United States with 19,804 cases reported in
2003, a continued decrease from the record number reported in 2002 (23,763 cases). CDC began
surveillance of Rocky Mountain spotted fever in 1970. The number of new cases of Rocky Mountain
spotted fever reported from 1995 to 2004 has fluctuated considerably, ranging between a low of 365 cases
in 1998 and a high of 1,713 cases in 2004. Reported cases increased slightly in 2004 (1,713 cases)
compared to 2003 (1,091 cases). Cases of West Nile virus were first documented in the United States in
1999. A total of 80 cases were reported in 1999 (62 cases) and 2000 (18 cases) (data not shown). West
Nile virus became nationally reportable in 2002, and the number of reported cases rose from 2,840 in
2002 to 2,866 in 2003. However, in 2004, the number of reported cases decreased to 1,142.
Exhibit 5-25. Number of reported cases of arthropod-borne diseases in the U.S., 1995-2004
Rocky Mountain spotted fever
'01 '02 '03 '04
'95 '96 '97 '98 '99 '00
West Nile virus was not on CDC's list of nationally notifiable infectious diseases prior to 2002.
Data source: CDC, Summary of Notifiable Diseases
Exhibit 5-26. Number of reported cases of
legionellosis in the U.S., 1995-2004
'95 '96 '97 '98 '99 '00 '01 '02 '03 '0
Year
Data source: CDC, Summary of Notifiable Diseases
West Mile virus"
Legionellosis
Exhibit 5-26 presents the number of reported
cases of legionellosis within the U.S.
population from 1995 to 2004. Through this
period, the number of new cases of
legionellosis was relatively stable, ranging
from a low of 1,108 cases in 1999 to 1,355
cases in 1998. However, in 2003, the number
of new cases reported increased to 2,232,
decreasing in 2004 to 2,093.
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1 Indicator Limitations
2 • State health departments report cases of notifiable diseases to CDC and policies for reporting
3 can vary by disease or reporting jurisdiction.
4 • Disease reporting likely underestimates the actual number of cases for a given time period
5 because reporting nationally notifiable diseases to CDC is voluntary. Additionally, the
6 completeness of reporting likely varies by disease. The degree of completeness of data
7 reporting is influenced by many factors such as the diagnostic facilities available, the control
8 measures in effect, public awareness of a specific disease, and the interests, resources, and
9 priorities of state and local officials responsible for disease control and public health
10 surveillance (CDC, 2006).
11 • Factors such as changes in case definitions for public health surveillance, introduction of new
12 diagnostic tests, or discovery of new disease entities can cause changes in disease reporting
13 that are independent of the true incidence of disease (CDC, 2004).
14 • For West Nile Virus, only confirmed "neuroinvasive" cases are reported, the most severe
15 form of the condition. West Nile virus may also include West Nile fever, which refers to
16 typically less severe cases with no evidence of neuroinvasion. West Nile fever is not currently
17 on the list of nationally notifiable diseases, and therefore it is optional whether or not state
18 health departments report these cases to CDC (CDC, 2005c).
19 Data Sources
20 The data for this indicator were obtained from CDC annual reports that summarize data on nationally
21 notifiable infectious diseases reported to CDC by state health agencies across the country (CDC, 1996,
22 1997, 1998b, 1999, 2001, 2002, 2003b, 2004, 2005b, 2006). Data are collected and compiled from reports
23 sent by state health departments to the National Notifiable Diseases Surveillance System (NNDSS),
24 which is operated by CDC. NNDSS is neither a single surveillance system nor a method of reporting.
25 Certain NNDSS data are reported to CDC through separate surveillance information systems and through
26 different reporting mechanisms; however, these data are aggregated and compiled for publication
27 purposes (CDC, 2006).
28 References
29 CDC (Centers for Disease Control and Prevention). 2006. Summary of notifiable diseases—United
30 States, 2004. MMWR 53(53). See Table 1.
31 CDC (Centers for Disease Control and Prevention). 2005a. Foodborne illness—frequently asked
32 questions. Accessed April 11, 2005.
33
34 CDC (Centers for Disease Control and Prevention). 2005b. Summary of notifiable diseases—United
35 States, 2003. MMWR 52(54). See Table 1.
36 CDC (Centers for Disease Control and Prevention). 2005c. West Nile virus statistics, surveillance, and
37 control: 2005 West Nile virus activity in the United States. Accessed October 16, 2005.
38
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1 CDC (Centers for Disease Control and Prevention). 2004. Summary of notifiable diseases—United
2 States, 2002. MMWR 51(53). See Table 1.
3 CDC (Centers for Disease Control and Prevention). 2003a. Legionnaires' disease fact sheet. Accessed
4 October 20, 2005.
5 CDC (Centers for Disease Control and Prevention). 2003b. Summary of notifiable diseases—United
6 States, 2001. MMWR 50(53). See Table 1.
7 CDC (Centers for Disease Control and Prevention). 2002. Summary of notifiable diseases—United
8 States, 2000. MMWR 49(53). See Table 1.
9 CDC (Centers for Disease Control and Prevention). 2001. Summary of notifiable diseases—United
10 States, 1999. MMWR 48(53). See Table 1.
11 CDC (Centers for Disease Control and Prevention). 2000. Update: West Nile virus activity—eastern
12 United States, 2000. MMWR 49(46): 1044-1047.
13
14 CDC (Centers for Disease Control and Prevention). 1999. Summary of notifiable diseases—United
15 States, 1998. MMWR 47(53). See Table 1.
16 CDC (Centers for Disease Control and Prevention). 1998a. Preventing emerging infectious diseases. A
17 strategy for the 21st century.
18 CDC (Centers for Disease Control and Prevention). 1998b. Summary of notifiable diseases—United
19 States, 1997. MMWR 46(54). See Table 1.
20 CDC (Centers for Disease Control and Prevention). 1997. Summary of notifiable diseases—United
21 States, 1996. MMWR 45(53). See Table 1.
22 CDC (Centers for Disease Control and Prevention). 1996. Summary of notifiable diseases—United
23 States, 1995. MMWR 44(53). See Table 1.
24 CDC (Centers for Disease Control and Prevention). 1993. Lyme disease—United States, 1991-1992.
25 MMWR 42(18):345-348.
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NDICATOR: Birth Defects Rates and Mortal!
2 Congenital anomalies, or birth defects, are structural defects that are present in the fetus at birth.
3 Although birth defects are the leading cause of infant mortality (deaths occurring to those <1 year of age)
4 in the United States, the cause is unknown for approximately 70 percent of all cases (Infant Mortality
5 indicator, p. 5-19) (CDC, 2005). Many different factors are associated with the development of birth
6 defects such as genetic and/or chromosomal aberrations, exposure to viruses or bacteria, uncontrolled
7 diabetes, cigarette smoke, use of drugs and alcohol during pregnancy, and prenatal exposure to chemicals
8 in the workplace or pollutants in the environment. All of these factors can change normal infant growth or
9 development resulting in different types of birth defects (NICHD, 2005).
10 This indicator presents birth defects rates at birth and mortality among infants in the United States as
11 recorded in the National Vital Statistics System (NVSS), which registers virtually all births and deaths
12 nationwide. Data collection began in 1933 and is available through 2003 (rates at birth) and 2002
13 (mortality). Birth defects data are collected on death certificates from all 50 States and the District of
14 Columbia and recorded on birth certificates for 49 States and the District of Columbia. Reported race and
15 ethnicity data are based on the race and ethnicity of the mother.
16 What the Data Show
17 Exhibit 5-27 presents the rate of live births with identified specific congenital anomalies (i.e., birth
18 defects) between 1999 and 2003. The most frequently occurring types of birth defects were various
19 musculoskeletal/integumental anomalies, circulatory/respiratory system anomalies, and heart
20 malformations. In 2003, heart malformations occurred at a rate of 128.9 per 100,000 live births, which
21 was highest among the specific anomalies listed (i.e., categories that do not include "other"). The overall
22 rate of birth defects (i.e., all birth defects combined) between 1999 and 2003 has been relatively stable
23 through the period, with the exception of a noticeable decline in 2003. Blacks have a consistently higher
24 rate of birth defects than whites during this time period, with a rate of 127.3 (blacks) compared with 101.6
25 (whites) birth defects per 100,000 live births in 2003 (data not shown).
26 Birth defects continue to be the leading cause of infant mortality, accounting for 5,621 (20.1 percent) of
27 the 28,025 infant deaths in 2003 (Exhibit 5-7, Infant Mortality indicator, p. 5-19). Between 1979 and
28 1998 a decline in the national birth defects mortality rate has been observed ranging from 255.4 per
29 100,000 live births in 1979 to 157.6 per 100,000 in 1998. From 1999 to 2003 the birth defects mortality
30 rates were 144.2 (1999), 150.9 (2000), 136.7 (2001), 139.4 (2002), and 140.4 (2003) per 100,000.
31 Birth defect mortality was consistently higher among black compared to white infants. In 2003, for
32 example, mortality attributed to birth defects among black male and female infants was 170.7 and 143.8
33 per 100,000 infants, respectively, and among white male and female infants was 143.2 and 131.8 per
34 100,000 infants, respectively. (Data not shown.)
35
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Exhibit 5-27. Rates of live births in the U.S
with specific birth defects (congenital anomalies), 1999-2003*
Central nervous system anomalies
Anencephalus
Spina bifida/meningocele
Mydrocephaljs
Microcephalus
Other central nervous system anomalies
Circulatory/respiratory anomalies
Heart malformations
Other circulatory/respiratory anomalies
Gastrointestinal anomalies
Rectal atresia/stenosis
Tracheo-esophageal fistula/esophageal atresia
Omphalocele/gastroschisis
Other gastrointestinal anomalies
Urogenital anomalies
Malformed genitalia
Renal agenesis
Other urogenital anomalies
Chromosomal anomalies
Polydactyly/syndactyly/adactyly
Clubfoot
Diaphragmatic hernia
Other musculoskeletal/integumental anomalies
Down's syndrome
Other chromosomal anomalies
Rates are per 100,000 live births.
Data source: NCHS, 2001; 2002a,b; 2003; 2005
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1 Indicator Limitations
2 • Because some birth defects are not recognized immediately, they are often underreported on
3 both birth and death certificates (Friis and Sellers, 1999). Many anomalies are hard to detect
4 at birth, which limits early ascertainment and complete reporting. The most serious and/or
5 apparent anomalies are more likely to be identified and reported prior to hospital discharge
6 (Honeinetal., 2001).
7 • The lack of uniform reporting on birth certificates introduces additional uncertainty. For
8 example, race information may be missing or incomplete. Also, beginning in 2003, two states
9 began using a revised "standard certificate of live birth;" therefore, a subset of anomaly data
10 was excluded because of the lack of comparability with other data sets (NCHS, 2005).
11 • The congenital anomalies reported on birth certificates are rare events. Since a small change
12 in the number of anomalies reported can result in a relatively large change in rates, caution
13 should also be used in comparing yearly rates for a specific anomaly.
14 • The birth defect anomaly groupings that include "other" (e.g., other musculoskeletal
15 anomalies) include a large number of non-specific birth defects and should be considered
16 separately from the specific birth defects listed.
17 • Birth defects mortality rates are based on underlying cause-of-death as entered on a death
18 certificate by a physician. Incorrect coding and low rates of autopsies that confirm the cause
19 of death may occur. Additionally, some individuals may have had competing causes of death.
20 "When more than one cause or condition is entered by the physician, the underlying cause is
21 determined by the sequence of conditions on the certificate, provisions of the ICD
22 [International Classification of Diseases], and associated selection rules and modifications"
23 (CDC, n.d.). Consequently, some misclassification of reported mortality might occur in
24 individuals with competing causes of death, as well as underreporting of some birth defects as
25 the cause of death.
26 • The International Classification of Diseases 9th Revision (ICD-9) codes were used to specify
27 underlying cause of death for years 1979-1998. Beginning in 1999, cause of death is specified
28 with the International Classification of Diseases 10th Revision (ICD-10) codes. The two
29 revisions differ substantially, and to prevent confusion about the significance of any specific
30 disease code, data queries are separate. The relatively large difference between birth defect
31 mortality rates reported from 1979 through 1998 and those reported beginning in 1999 may
32 be due to some changes in the criteria used to report birth defect mortality during the switch
33 from ICD-9 to ICD-10.
34 Data Sources
35 The birth defects rate data used for this indicator are from National Vital Statistics Reports published by
36 CDC's National Center for Health Statistics (NCHS, 2001; 2002a,b; 2003; 2005). The birth defects
37 mortality data were obtained from a published report by CDC's National Center for Health Statistics
38 (NCHS, 2006) and from CDC's compressed mortality files (underlying cause of death), accessed via
39 CDC WONDER (CDC, 2006), at htto://wonder.cdc.gov.
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1 References
2 CDC (Centers for Disease Control and Prevention). 2006. CDC Wide-ranging OnLine Data for
3 Epidemiologic Research (WONDER). Compressed mortality file, underlying cause of death. 1999-2003
4 (with ICD 10 codes) and 1979-1998 (with ICD 9 codes). Accessed 2006.
5
6 CDC (Centers for Disease Control and Prevention). 2005. Birth defects. Accessed February 7, 2005.
7
8 CDC (Centers for Disease Control and Prevention), n.d. CDC WONDER: Help page for compressed
9 mortality file,
10 Friis, R.H., and T.A. Sellers. 1999. Epidemiology for public health practice. Second ed. Gaithersburg,
11 MD: Aspen Publishers, Inc.
12 Honein, M.A., L.J. Paulozzi, and M.L. Watkins. 2001. Maternal smoking and birth defects: validity of
13 birth data for effect estimation. Public Health Reports 116:327-335.
14 NCHS (National Center for Health Statistics). 2006. Deaths: final data for 2003. National Vital Statistics
15 Reports 54(13). April 19.
16 NCHS (National Center for Health Statistics). 2005. Births: final data for 2003. National Vital Statistics
17 Reports 54(2). See Table 49.
18 NCHS (National Center for Health Statistics). 2003. Births: final data for 2002. National Vital Statistics
19 Reports 52(10). See Table 49.
20 NCHS (National Center for Health Statistics). 2002a. Births: final data for 2001. National Vital Statistics
21 Reports 51(2). See Table 49.
22 NCHS (National Center for Health Statistics). 2002b. Births: final Data for 2000. National Vital Statistics
23 Reports 50(5). See Table 49.
24 NCHS (National Center for Health Statistics). 2001. Births: final data for 1999. National Vital Statistics
25 Reports 49(1). See Table 49.
26 NICHD (National Institute of Child Health and Human Development). 2005. Birth defects and human
27 development. Accessed February 3, 2005.
28
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NDICATOR: Low Birthweii
2 "Low birthweight" (LEW) is typically defined as any infant weighing <2,500 grams at birth. Weight is a
3 critical health measure because LEW children are more prone to death and disability than their
4 counterparts.
5 Environmental exposures have been implicated as a risk factor for LEW (e.g., maternal smoking,
6 maternal exposure to lead, diethylstilbestrol, occupational exposures) (Sram et al., 2005; Kiely et al.,
7 1994). However, the etiology of term-LBW (born 37+ weeks gestation) infants and preterm-LBW (born
8 <37 weeks gestation) infants differs. For term-LBW infants, underlying causes include factors such as
9 maternal smoking, weight at conception, and gestational weight gain, whereas for preterm-LBW infants,
10 the etiology largely remains unexplained (CDC, 1994).
11 This indicator presents the percentage of LEW infants born in the U.S. based on natality data reported to
12 the National Vital Statistics System (NVSS). The NVSS registers virtually all deaths and births
13 nationwide with data coverage from 1933 to 2003 and from all 50 States and the District of Columbia.
14 The data presented are based on singleton births only. This was done to eliminate the effect of multiple
15 births. The data are presented across three maternal age groups (< 20, 20-39, and 40 and over).
16 Additionally, the data are stratified and reported for preterm (less than 37 weeks) and full-term (37 weeks
17 and over) births because of the strong association between birthweight and gestational age.
18 What the Data Show
19 As expected, the percent of total LEW deliveries among preterm births are much higher than the percent
20 of total LEW deliveries among full term births across each of the three maternal age categories (Exhibits
21 5-28 and 5-29).
22 In general, small differences in the percent of LEW babies among maternal age categories are evident for
23 both pre- and full-term births. For example, in 2002, the frequency of LEW babies among full-term births
24 for mothers less than 20 years old (3.9 percent) is about 1 percent higher than mothers who are 40 years
25 and older (3.0 percent) and about 1.5 percent higher than mothers who are in the 20-39 age group (2.4
26 percent) (Exhibit 5-29).
27 Among the full-term births, black women had consistently higher frequencies of LEW babies compared
28 to any of the other racial groups reported from 1995 and 2002. This racial pattern is evident in 2002 for
29 all three maternal age groups and the difference is most apparent in the 40 and older age group (6.2
30 percent for blacks and 2.5 percent for whites) (Exhibit 5-29).
31 The percentage of LEW babies among the other two racial groups reported in 2002, Native Americans
32 and Asians/Pacific Islanders, was 2.4 percent and 3.5 percent, respectively, for the 40 and older age
33 group. For Native Americans, there was little variation in frequency of LEW among the three different
34 age groups reported (< 20 years, > 20-39 years, and 40 and older) during 2002, whereas Asian/Pacific
35 Islanders fluctuations across age groups were somewhat greater. Hispanic women and non-Hispanic
36 women had very similar frequencies of LEW babies. For example, in 2002, the percent of LEW babies
37 for Hispanic women was 2.3 percent compared to 2.6 percent for non-Hispanic women. (Data not shown.)
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Exhibit 5-28. Percent of low birthweight infants (<2,500 grams) born preterm in the U.S. by mother's
race and age, 1995-20023 b
A. Mathers 0
10
0
1 =j
t=J
>- -<
h — '
B. Mothers 20-39 years
C. Mothers 40+ years
'95 '96 '97 '98 '99 '00 '01 '02 '03 '95 '96 '97
'00 '01 '02 '03 '95 '96 '97 '98 '99 '00 '01 '02 '03
Year
aPreterm births are births occurring at <37 weeks gestation.
bData represent singleton births only.
Data source: CDC WONDER natality data
Exhibit 5-29. Percent of low birthweight infants (<2,500 grams) born full-term in the U.S. by mother's
race and age, 1995-20023 b
10
9
8
7
*- 6
1 •'
£ 4,
2
1
0
'9
aFull-te
bData r
Data
A. Mathers
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1 References
2 CDC (Centers for Disease Control and Prevention). 2006. CDC Wide-ranging OnLine Data for
3 Epidemiologic Research (WONDER). Natality data query. Accessed 2006.
4
5 CDC (Centers for Disease Control and Prevention). 1994. Increasing incidence of low birthweight—
6 United States, 1981-1991. MMWR 43:335-339. Accessed February 2, 2005.
7
8 Kiely, J.S., K.M. Brett, S. Yu, and D.L. Rowley. 1994. Low birthweight and intrauterine growth
9 retardation. In: Wilcox, L.S., and J.S. Marks, eds. From data to action: CDC's public health surveillance
10 for women, infants, and children. CDC's maternal and child health monograph 1994. Atlanta, GA:
11 Centers for Disease Control and Prevention.
12 Sram R.J., B Binkova, J. Dejmek, and M. Bobak. 2005. Ambient air pollution and pregnancy outcomes: a
13 review of the literature. Environ. Health Perspect. 113(4): 375-382
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INDICATOR: Preterm Delivery
2 Preterm delivery is defined as delivery prior to 37 weeks of gestation (a typical pregnancy lasts 40
3 weeks). The shorter the gestational age of an infant, the more likely (s)he is to suffer adverse effects.
4 Preterm birth along with low birthweight is the second leading cause of infant death (Infant Mortality
5 indicator, p. 5-19) (NCHS, 2004, 2005), and is associated with nearly half of all neurological birth defects
6 (Goldenberg and Rouse, 1998; NCHS, 2005).
7 The determinants of preterm births are not fully known and the causes are often multi-factorial. Maternal
8 high risk conditions (e.g., infertility problems, vaginal spotting, inadequate maternal weight gain),
9 maternal previous history, socioeconomic status, smoking, alcohol consumption before third trimester,
10 and multiple gestation pregnancy are known risk factors for preterm delivery. Environmental
11 contaminants (e.g., lead, environmental tobacco smoke, air pollution) continue to be studied to better
12 understand the likely associations with preterm delivery.
Exhibit 5-30. Preterm deliveries in the U.S. by
mother's age and race, 1995-2002""
A. Preterm deliveries by mother's age
i\l
18
16
14
„ 12'
§ 10,
£ 8
6
4
2
0
; * ^j — -A — : — -i — • • •
•*• All groups
-*• <20 years
•*• 20 39 years
•*• 40+ years
'95 '96 '97 '98 '99 '00 '01 '02 '03
Year
B. Preterm deliveries by mother's race
£(l
18
14
12
8
6
4
2
__u_ — . — • — . — • — •
•»• All groups
•*• Black
* White
'95 '96 '97
'00 '01 '02 '03
Year
"Preterm deliveries are births occurring at <37 weeks gestation.
bData represent singleton births only.
Data source: CDC WONDER natality data
This indicator presents the proportion of U.S. infants
born prior to 37 weeks of gestation, based on natality
data reported to the National Vital Statistics System
(NVSS). The NVSS registers virtually all deaths and
births nationwide with data coverage from 1933 to
2003 and from all 50 States and the District of
Columbia. The data presented here on preterm
delivery were based on singleton births only. This
was done to eliminate the effect of multiple births.
The data are presented across three maternal age
groups (< 20 years, 20-39 years, and 40 years and
over).
What the Data Show
The proportion of infants defined as preterm has risen
14 percent since 1990 (NCHS, 2003). A small overall
increase in preterm births has been observed from
1995 (9.8 percent) to 2002 (10.4 percent). The largest
percent increase between 1995 and 2000 has occurred
among mothers in the 40 and over age group, with the
percent of preterm births ranging from 12.0 (1995) to
13.1 percent (2002). The next largest percent increase
was observed in the 20-39 year old maternal group,
ranging from 9.2 percent (1996) to 10.0 percent
(2002), with little change over time among those less
than 20 years of age (Exhibit 5-30, panel A).
In 1995, the percent of preterm births was almost
twice as high among black mothers compared to
white mothers (16.4 versus 8.5 percent) (Exhibit 5-30,
panel B). Between 1995-2002, preterm delivery
among black mothers decreased slightly from 16.4
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1 percent in 1995 to 15.9 percent in 2002. During the same time, preterm delivery among white mothers
2 increased slightly, rising from 8.5 percent in 1995 to 9.5 percent in 2002, resulting in a slight narrowing
3 of the difference in the preterm birth rate between black and white mothers. Preterm delivery for Hispanic
4 mothers ranged from 10.1 (1995) to 10.6 percent (2002) compared to 9.7 (1996) and 10.4 (2002) percent
5 for non-Hispanic mothers between 1995 and 2002. (Data not shown.)
6 Indicator Limitations
7 • "The primary measure used to determine the gestational age of the newborn is the interval
8 between the first day of the mother's last normal menstrual period (LMP) and the date of
9 birth." This measurement is subject to error, including imperfect maternal recall or
10 misidentification of the LMP because of postconception bleeding, delayed ovulation, or
11 intervening early miscarriage These data are edited for LMP-based gestational ages, which
12 are clearly inconsistent with the infant's plurality and birthweight, but reporting problems for
13 this item persist and may occur more frequently among some subpopulations and among
14 births with shorter gestations (NCHS, 2003).
15 • Preterm delivery data were extracted from the CDC WONDER database. Slight differences in
16 percentages were obtained compared to reports by NCHS (2003). The source of these
17 differences in unknown.
18 Data Source
19 The data used for this indicator were obtained from CDC's National Center for Health Statistics, Division
20 of Vital Statistics, natality public-use data (1995-2002) available via CDC WONDER (CDC, 2006), at
21 http: //wonder, cdc. gov.
22 References
23 CDC (Centers for Disease Control and Prevention). 2006. CDC Wide-ranging OnLine Data for
24 Epidemiologic Research (WONDER). Natality data query. Accessed 2006.
25
26 Goldenberg, R.L., and D.J. Rouse. 1998. Prevention of premature birth. New Engl. J. Med. 339:313-320.
27 NCHS (National Center for Health Statistics). 2005. Births: final data for 2003. National Vital Statistics
28 Reports 54(2). Accessed December 20, 2005.
29
30 NCHS (National Center for Health Statistics). 2004. Infant mortality statistics from the 2002 period
31 linked birth/infant death data set. National Vital Statistics Reports 53(10).
32 NCHS (National Center for Health Statistics). 2003. Births: final data for 2002. National Vital Statistics
33 Reports 52(10). Accessed November 21, 2005.
34
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1 5.3.3 Discussion
2 What These Indicators Say About Trends in Diseases and Conditions for
3 Which Environmental Contaminants May Be a Risk Factor
4 The indicators selected to answer this question represent diseases and conditions that affect multiple
5 systems of the human body and are associated with a number of causal factors, some of which include
6 contaminants in the air, water, and land. Some indicators represent chronic conditions (e.g., various
7 cancers, heart and lung disease), some are primarily acute in nature (e.g., infectious diseases), and others
8 represent conditions of the developing fetus and neonate. Understandably, no striking trends are evident
9 across the broad categories of diseases represented by the indicators. However, some changes in disease
10 rates or occurrence were observed for individual indicators. These relate largely to disease patterns
11 observed over time and to differences observed across age groups, gender, and racial and ethnic groups.
12 Generally, the occurrence of many chronic diseases in adults is increasing with the aging of the
13 population (Cancer indicator, p. 5-31; Cardiovascular Disease indicator, p. 5-37; Chronic Obstructive
14 Pulmonary Disease indicator, p. 5-43). However, while overall cancer incidence rates showed a steady
15 increase from the mid-1970s to the mid-1990s, rates have held relatively steady between 1997 and 2003.
16 With the exception of prostate cancer in males and breast cancer in females, site-specific cancer rates also
17 have remained fairly constant. Similarly, prevalence rates for CVD and COPD have shown no striking
18 changes between 1997 and 2003. Prevalence rates for adult asthma have increased slightly between 1997
19 and 2001, with slight declines from 2002 to 2004 (Asthma indicator, p. 5-48).
20 No distinct upward or downward patterns were revealed between 1995 and 2004 for most of the acute
21 infectious gastrointestinal diseases presented in this report. One exception is the decrease in Hepatitis A
22 cases, which have been attributed to childhood vaccination for this disease.36 Generally increased reported
23 occurrence of arthropod-borne diseases and legionellosis bear watching (Infectious Diseases indicator, p.
24 5-53).
25 Review of diseases in children and birth outcomes revealed the following overall trends. Childhood
26 cancer incidence has increased slightly since 1975, with boys having a higher incidence rate than girls.
27 Leukemia and brain and other nervous system cancers remain the leading cancer sites in children
28 (Childhood Cancer indicator, p. 5-35). As with adults, prevalence rates for childhood asthma have not
29 changed much between 1997 and 2004, though a 4 percent increase was reported between 1980 and the
30 mid-1990s (Asthma indicator, p. 5-48). A wide range of birth defects continues to be reported each year,
31 but with no great shifts in rates observed for specific types of defects from 1999 to 2003. Heart anomalies
32 and physical defects remain the most prevalent types of birth defects based on birth certificate data (Birth
33 Defects indicator, p. 5-58). Among full-term singleton births, the percentage of low birthweight infants
34 has not varied greatly from 1995 and 2002. Age of mother showed the greatest influence, with the
35 greatest number of low birthweight infants born to younger mothers (less than 20 years old) (Low
36 Birthweight indicator, p. 5-62). The highest rate of preterm births is also seen in these younger mothers,
37 though nearly comparable and rising pre-term birth rates are seen among mothers over the age of 40
38 (Preterm Delivery indicator, p. 5-65).
36 Centers for Disease Control and Prevention. 2005. Summary of notifiable diseases—United States, 2003. MMWR
52(54):5-14.
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1 Some differences were observed across racial and ethnic groups. Observations are reported for the most
2 recently available annual data set. Overall, cancer incidence is higher among black males than for any
3 other racial group. Less disparity was observed between cancer incidence in white and black women.
4 With childhood cancers, higher rates have been consistently reported in whites than in blacks (Cancer
5 indicator, p. 5-31, Childhood Cancer indicator, p. 5-35). For cardiovascular disease (p. 5-37), prevalence
6 rates are highest in American Indian/Alaska Natives, followed by whites, blacks or African Americans,
7 and Asians. Asthma rates were generally reported highest among blacks or African Americans in children
8 and American Indian/Alaska Natives in adults, followed by, whites, and Asians (Asthma indicator, p. 5-
9 48).
10 The percentage of preterm and low birthweight infants is consistently higher among blacks than in whites
11 (1.5 to nearly 3 times higher). This observation is seen across all maternal age groups (Preterm Delivery
12 indicator, p. 5-65; Low Birthweight indicator, p. 5-62). When available, reported disease rates were
13 generally lower (Asthma indicator, p. 5-48; Cardiovascular Disease indicator, p. 5-37) or comparable
14 (Preterm Delivery indicator, p. 5-65; Low Birthweight indicator, p. 5-62) in non-Hispanic and Hispanic
15 populations.
16 Limitations, Gaps, and Challenges
17 In answering this question, EPA reviewed general trends in morbidity and mortality of several diseases
18 that may be related, at least in part, to environmental contaminant exposures. The indicators presented in
19 this section provide an overall picture of specific disease rates or occurrence across the nation, including
20 among some population subgroups. ROE indicator data sets, however, do not enable extensive analysis of
21 disease trends within or across geographic regions, nor do they allow fully consistent reporting of trends
22 across racial and ethnic groups. In addition, other diseases or conditions of potential interest exist, but for
23 which no national scale data are currently available, or for which the strength of associations with
24 environmental contaminants are still being evaluated. Specific limitations, data gaps, and challenges
25 related to answering the question on trends in disease are highlighted below.
26 Geographic patterns. Mortality data sets enable some analysis at the EPA regional level, but underlying
27 data for most ROE indicators selected to answer this question do not enable meaningful analysis of
28 geographic trends across the nation. The regional analyses presented in this report for CVD and COPD
29 mortality reveal no discernable patterns.
30 Other diseases and conditions for which environmental contaminants may be risk factors. Additional data
31 are needed to prompt or enable EPA to track other diseases and conditions with potential environmental
32 risk factors (direct or indirect), particularly those for which unexplained increases are being noted.
33 Examples of diseases or conditions with suggestive or growing evidence that environmental contaminants
34 are a risk factor follow. The extent to which national-level indicators meeting ROE criteria are available
35 to track these diseases and conditions varies.
36 Behavioral and neurodevelopmental disorders in children continue to receive attention. These include
37 disabilities of the functioning brain that affect a child's behavior, motor skills, memory, or ability to learn.
38 Examples include attention-deficit/hyperactivity disorder (ADHD), dyslexia and other learning
39 disabilities, cerebral palsy, mental retardation, and autism. Considerable evidence exists documenting that
40 lead and methylmercury are associated with mental retardation and impairment of mental function and
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1 attention.37 While the role of other environmental contaminants in contributing to some of these disorders
2 is not fully known or understood (e.g., ADHD), the weight of evidence suggesting relationships between
3 behavioral and neurodevelopmental effects from exposure to PCBs, environmental tobacco smoke, and
4 other contaminants continues to grow.38'39NHIS tracks ADHD and mental retardation, though the
5 accurate reporting of these types of disorders is complicated by the difficulties in diagnoses and possible
6 underreporting (e.g., institutionalized children are excluded from the NHIS survey population).
7 As the U.S. population continues to age, more individuals are afflicted with neurodegenerative disorders
8 such as Parkinson's disease and Alzheimer's disease. For example, Alzheimer's disease is the eighth
9 leading cause of death in the nation (General Mortality indicator, p. 5-13). Such diseases are characterized
10 by the progressive loss of neural cells, which lead to central nervous system dysfunction (e.g., memory
11 loss, cognitive deficits, personality changes, motor control abnormalities). The etiology of these disorders
12 is multifactorial, but in many cases the etiology is unknown. Ongoing research is exploring the role, if
13 any, of environmental contaminant exposure (e.g., heavy metals, pesticides). Thus far, findings are largely
14 inconclusive due to conflicting results.40
15 Diabetes was reported as the sixth leading cause of death in the United States in 2002 (General Mortality
16 indicator, p. 5-13). Two types of diabetes exist. Diabetes mellitus (type 2), the most common form of
17 diabetes, is characterized by the body's resistance to insulin action and a relative deficiency of insulin.
18 Known risk factors for diabetes mellitus include factors such as age, obesity, family history, physical
19 inactivity, and dietary glycemic load. Type 1 diabetes results from decreased insulin production by the
20 pancreas as part of an autoimmune response. Onset typically occurs before adulthood and believed to be
21 triggered by genetic predisposition and possible environmental factors. Diabetes itself is a risk factor for
22 the development of many other acute and chronic conditions. Epidemiological research has been
23 conducted to evaluate possible associations between environmental contaminant exposure and diabetes;
24 however, findings are inconclusive. Occupational and environmental exposures to contaminants such as
25 arsenic, PCBs, dioxins, and nitrates have been examined.41'42 Other endocrine and metabolic disorders,
26 such as thyroid disorders continue to be studied. Research suggests that various environmental
37 Mendola P., S.G. Selevan, S. Gutter, and D. Rice. 2002. Environmental factors associated with a spectrum of
neurodevelopmental deficits. Ment. Retard. Dev. Disabil. Res. Rev. 8(3): 188-197.
38 Schantz, S.L., JJ. Widholm, and D.C. Rice. 2003. Effects of PCB exposure on neuropsychological function in
children. Review. Environ. Health Perspect. lll(3):357-376.
39 State of California. 2005. Proposed identification of environmental tobacco smoke as a toxic air contaminant. Part
B: health effects assessment for environmental tobacco smoke. As approved by the Scientific Review Panel on June
24, 2005. California Environmental Protection Agency, Office of Environmental Health Hazard Assessment.
40 Brown, R.C., A.H. Lockwood, and B.R. Sonawane. 2005. Neurodegenerative disorders: an overview of
environmental risk factors. Environ. Health Perspect. 113(9): 1250-1256.
41 Longnecker, M.P., and J.L. Daniels. 2001. Environmental contaminants as etiologic factors for diabetes. Environ.
Health Perspect. 109(Suppl 6):871-876.
42 Remillard, R.B., and N.J. Bunce. 2002. Linking dioxins to diabetes: epidemiology and biologic plausibility.
Review. Environ. Health Perspect. 110(9):853-858.
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1 contaminants are capable of disrupting endocrine function in many species, including humans (e.g.,
2 phthalates, POPs).
3 Reproductive function is another condition of interest to EPA. Scientists are studying whether
4 environmental contaminants may cause alterations in reproductive function and contribute to conditions
5 such as ovarian failure, decreased sperm counts, infertility, sub-fecundity, and possibly early onset of
6 puberty. For example, components of cigarette smoke and other environmental contaminants have been
7 studied in association with possible effects on female reproductive function.43 Other contaminants under
8 study include pesticides, dioxins, various metals, and solvents.
9 Renal disease is of interest because of the vital function of the kidneys in maintaining human health and
10 the range of complex factors that lead to kidney dysfunction and disease. The kidneys can be seriously
11 affected by a number of primary diseases such as hypertension and diabetes. Nephritis and nephritic
12 syndrome were reported as the ninth leading cause of death in 2002 (General Mortality indicator, p. 5-13).
13 EPA is interested because the kidney is known to be the target of some environmental contaminants. For
14 example, as evidenced through occupational exposure, poisoning, and other experimental studies,
15 exposure to heavy metals such as lead, cadmium, and mercury has been shown to be nephrotoxic.44'45 The
16 U.S. Renal Data System is a national data system that collects, analyzes, and distributes morbidity and
17 mortality information about end-stage renal disease (ESRD) in the United States.
18 Infectious diseases represent a continuing threat in the United States and worldwide. CDC continues to
19 monitor infectious diseases and implement preventive strategies for infectious diseases whose incidence
20 has increased within the past two decades or threatens to increase in the near future.46 Infectious diseases
21 of EPA interest may shift over time, making tracking of these diseases more of a challenge. An area of
22 research interest for arthropod-borne diseases, and a potential issue for zoonotic diseases, is whether their
23 incidence may change with changes in environmental condition such as land use, local weather
24 conditions, or other environmental disturbances.
25 Other data collection systems. To better answer the question, expanded national-level health data
26 collection systems are needed, as well as integration of systems that collect health data. For example, the
27 birth certificate data currently used to track birth defects on a national level have limitations (see Birth
28 Defects indicator, p. 5-58). The CDC recognizes the need for continuing efforts to improve birth defects
29 surveillance and recently released improved national prevalence estimates for major birth defects looking
30 at data reported through the National Birth Defects Prevention Network.47 Also, as noted above, systems
43 Mlynarcikova, A., M. Fickova, and S. Scsukova. 2005. Ovarian intrafollicular processes as a target for cigarette
smoke components and selected environmental reproductive disrupters. Review. EndocrRegul. 39(l):21-32.
44 Klaassen, C.D., ed. 2001. Casarett and Doull's toxicology: the basic science of poisons. Sixth ed. New York, NY:
McGraw-Hill.
45
Jarup, L. 2003. Hazards of heavy metal contamination. Review. Br. Med. Bull. 68:167-182.
46 Centers for Disease Control and Prevention. 1998. Preventing emerging diseases. A strategy for the 21st century.
Atlanta, GA: U.S. Department of Health and Human Services.
47 Centers for Disease Control and Prevention. 2006. Improved national prevalence estimates for 18 selected major
birth defects—United States, 1999-2001. MMWR 54(51&52):1301-1305.
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1 do not exist at the state or national level to track many of the diseases or conditions that may be related to
2 environmental hazards. Existing environmental hazard, exposure, and disease tracking systems are not
3 linked together.
4 Some efforts are underway to begin tracking exposure and health outcomes together. For example, CDC's
5 "environmental public health tracking network" involves the collection and integration of data from
6 environmental hazard monitoring and from human exposure and health outcome surveillance; CDC's goal
7 is to build a national tracking network (http ://www.cdc. gov/nceh/tracking/). In addition, CDC has
8 initiated the "environmental public health indicator project," which identifies indicators of environmental
9 hazards and health effects that state health departments can use to develop comprehensive environmental
10 public health programs (http://www.cdc.gov/nceh/indicators/default.htm). Such programs will help bridge
11 some existing gaps in knowledge between disease trends and environmental condition. These efforts also
12 will enhance data collection efforts at the community level (state and local) and help ensure better
13 temporal and spatial congruence between environmental, surveillance, and biomonitoring programs.
14
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1 5.4 WHAT ARE THE TRENDS IN HUMAN EXPOSURE TO ENVIRONMENTAL
2 CONTAMINANTS, INCLUDING ACROSS POPULATION SUBGROUPS AND
3 GEOGRAPHIC REGIONS?
4 5.4.1 Introduction
5 Understanding the extent to which human populations are being exposed to environmental contaminants
6 helps identify those contaminants of potential public health concern and populations who may be
7 disproportionately exposed to contaminants, such as children, women of childbearing age, certain race or
8 ethnic groups, or other potentially susceptible subgroups. Tracking the levels of environmental
9 contaminants in a population also enables an assessment of how exposures to those contaminants are
10 changing in that population.
11 Referring back to the Environmental Public Health Paradigm presented in Section 5.1.1, measurements of
12 human exposure to environmental contaminants can be made in the ambient environment (air, water,
13 land), at the point of human contact, or after contact and contaminant entry into the human body has
14 occurred. The sidebar on the next page further distinguishes the different types of exposure measures. In
15 answering this question, the focus is on human biomonitoring, which involves the measurement of human
16 tissues or excreta for direct or indirect evidence of exposure to chemical, biological, or radiological
17 substances. The ambient pollutant measurements presented in the media chapters are not considered here,
18 nor can they be directly linked with biomonitoring data presented to answer this question.
19 Historically, human exposure has been defined as the amount of a chemical, physical, or biological
20 contaminant at the outer boundary of the body available for exchange or intake via inhalation, ingestion,
21 or skin or eye contact.48 As such, human exposure to environmental contaminants has been estimated
22 primarily through measurements of contaminant concentrations in air, water, or soil, combined with
23 estimates of the frequency and duration of human contact with the contaminated media. These resulting
24 exposure estimates have provided a valuable foundation for many of the regulatory and non-regulatory
25 actions that have been taken to limit exposure to ambient contaminants. However, developments in data
26 collection techniques and analytical methods have improved the capability to characterize human
27 exposure via biomonitoring, which provide measurements of contaminants within the human body.
28 For a few environmental contaminants, particularly lead and some other metals, biomonitoring has been
29 used for exposure characterization for a number of years. More recently, techniques for biomonitoring
30 have been expanded to include many additional environmental contaminants. These measurements
31 provide a tool that complements ambient measurements in characterizing human exposure to
32 environmental contaminants, However, concentrations of environmental contaminants reported at a
33 national level in blood, urine, or any other type of tissue cannot be used to extrapolate directly to a
34 particular source.
35 The use of biological markers (or biomarkers) builds on the more traditional exposure assessment
36 approach, providing more information on the extent to which a contaminant enters, remains, and acts in
37 the body. Biomarker information attempts to determine the extent to which a contaminant is present in the
38
48 Aldrich, T., J. Griffith, C. Cooke. 1993. Environmental epidemiology and risk assessment. New York, NY: Van
Norstrand Reinhold.
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Measuring Human Exposure
Various approaches can be used to measure or estimate the levels of human exposures. No approach
is best suited to all environmental contaminants, and each approach has strengths and weaknesses.
Available biomonitoring data are used to answer the question on trends in human exposure to
environmental contaminants.
Ambient pollutant measurements. Historically, human exposures have been estimated using
environmental measurements of ambient pollutant concentrations. One limitation of ambient
measurements is that the presence of a contaminant in the environment may not be fully informative
regarding the extent to which individuals are exposed. In some cases, emissions data are used to
model or estimate ambient concentrations.
Models of exposure. This approach combines knowledge of environmental contaminant
concentrations with information on people's activities and locations (e.g., time spent working, exercising
outdoors, sleeping, shopping) to account for the contact with pollutants. This approach requires
knowledge of pollutant levels where people live, work, and play, as well as knowledge of their day-to-
day activities. Since model output is not a direct measure of environmental conditions or exposure, it is
not considered to be a true indicator of exposure.
Personal monitoring data. With personal monitoring, the monitoring device is worn by individuals as
they engage in their normal day-to-day activities. This approach is most commonly used in workplace
environments. Personal monitoring data provide valuable insights into the source of contaminants to
which people are actually being exposed. However, a challenge with personal monitoring (as with
biomonitoring) is ensuring that sufficient sampling is conducted to be representative of the population
being studied. No national-scale level personal monitoring data are available.
Biomonitoring data. Several environmental contaminants, notably heavy metals and some pesticides
and other persistent organic pollutants, can accumulate in the body. These pollutants or their
metabolites can be measured in human tissues or fluids such as blood or urine. These residues reflect
the amount of contaminant that gets into or is present in the body, but by themselves do not provide
information on how the person came into contact with the contaminant.
2 body after entering through portals of entry such as the eyes, skin, stomach, intestines, or lungs. Given the
3 complex set of factors that govern contaminants that are absorbed and distributed in the body, a direct
4 measurement of the levels of a contaminant or related "marker" in the body offers more information about
5 exposure than measured ambient levels alone.
6 In general, a biomarker reports the level of a substance or a marker (i.e., the product of an interaction
7 between an agent and some target molecule or cell) present in samples collected from the body or
8 produced by the body. Biomarkers of exposure measure concentrations of a contaminant, its
9 metabolite(s), or reaction product(s) in the body fluids or tissue, most commonly blood or urine.
10 Measurements can also be taken from a variety of other body compartments, such as feces, breast milk,
11 hair, nails, exhaled air, and tissues obtained through biopsy or autopsy. The exposure measure used to
12 answer this question focuses on biomarkers of exposure. Biomarkers of exposure do not predict whether
13 biological alterations and potential health effect will result. Whether a particular exposure ultimately
14 results in an adverse health outcome depends on a host of factors, as is described in Section 5.1 of this
15 chapter.
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l 5.4.2 Indicators
2 The answer to the question on trends in human exposure relies on national-scale biomonitoring data
3 collected as part of CDC's National Health and Nutrition Examination Survey (NHANES), primarily data
4 collected from 1999-2002. As part of the survey, blood and urine samples are routinely collected to
5 measure certain contaminants (or their metabolites) of public health concern. NHANES is conducted
6 annually, but the data are combined and reported for a two-year time period to provide more stable
7 population estimates and to obtain adequate sample sizes for many subgroup analyses. The chemicals in
8 CDC's current suite of biomarkers are based largely on scientific data that suggest exposure in the U.S.
9 population, the seriousness of known or suspected health effects associated with some levels of exposure,
10 the availability and adequacy of analytical methods, along with logistical and cost considerations.49
11 Seven individual or groups of contaminants from NHANES are considered, including metals, persistent
12 organic pollutants (POPs), pesticides, and phthalates (Table 5.3.1). The data presented represent data from
13 NHANES in its entirety or a subset of the original data, with emphasis on those compounds for which
14 CDC was able to calculate geometric means.50 The levels of detection (LOD) presented in the tables that
15 follow vary from chemical to chemical. The LOD is the level at which the measurement has a 95 percent
16 probability of being greater than zero. Percentile estimates that are less than the LOD for the chemical
17 analysis are reported as "
50 Geometric means are calculated by taking the log of each concentration, then calculating the mean of those log
values, and finally, taking the antilog of that mean. A geometric mean provides a better estimate of central tendency
and is influenced less by high values than is the arithmetic mean. This type of distribution is common when
measuring environmental chemicals in blood or urine (CDC 2005).
51 Centers for Disease Control and Prevention. 2005. Third national report on human exposure to environmental
chemicals. NCEH publication no. 05-0570.
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1 Table 5.4.1. ROE Indicators of Trends in Biomarkers of Exposure to Common Environmental
2 Contaminants
NATIONAL INDICATORS
Blood Lead Level
Blood Mercury Level
Blood Cadmium Level
Blood Persistent Organic Pollutants Level
Blood Cotinine Level
Urinary Pesticide Level
Urinary Phthalate Level
LOCATION
5.4.2 -p. 5-76
5.4.2 -p. 5-79
5.4.2 -p. 5-82
5.4.2 -p. 5-85
2.4.2 -p. 2-114
5.4.2 -p. 5-94
5.4.2 -p. 5-100
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INDICATOR: Blood Lead Level
2 Lead is a naturally occurring metal found in small amounts in rock and soil. Lead has been used
3 industrially in the production of gasoline, ceramic products, paints, metal alloys, batteries, and solder.
4 While lead arising from the combustion of leaded gasoline was a major source of exposure in past
5 decades, today lead based paint and lead-contaminated dust from paint are the primary sources of lead
6 exposure in the home. Lead levels can be measured in blood or urine.
7 Lead is a neurotoxic metal that affects areas of the brain that regulate behavior and nerve cell
8 developments (NRC, 1993). Its adverse effects range from subtle responses to overt toxicity, depending
9 on how much lead is taken into the body and the age and health status of the person (CDC, 1991). Lead is
10 one of the few pollutants for which biomonitoring and health effect data are sufficient to clearly evaluate
11 environmental management efforts to reduce lead in the environment.
12 Infants, children, and fetuses are more vulnerable to the effects of lead because the blood-brain barrier is
13 not fully developed (Nadakavukaren, 2000). Thus, a smaller amount of lead will have a greater effect in
14 children than in adults. In addition, ingested lead is more readily absorbed into a child's bloodstream,
15 while adults absorb only 10 percent. Because of lead's adverse effects on cognitive development, CDC
16 has defined an elevated blood lead level as equal to or greater than 10 micrograms/deciliter ((ig/dL) for
17 children under 6 years of age (CDC, 2005).
18 This indicator is based on data collected by the National Health and Nutrition Examination Survey
19 (NHANES). NHANES is a series of surveys conducted by CDC's National Center for Health Statistics
20 (NCHS) that is designed to collect data on the health and nutritional status of the civilian, non-
21 institutionalized U.S. population using a complex, stratified, multistage, probability-cluster design. CDC
22 began monitoring blood lead in 1976 as part of NHANES II, which covered the period 1976 through
23 1980. Blood lead was also monitored in NHANES III, which covered the period between 1988 and 1994.
24 CDC's National Center for Environmental Health (NCEH) conducted the laboratory analyses for the
25 biomonitoring samples. Beginning in 1999, NHANES became a continuous and annual national survey
26 visiting 15 U.S. locations per year and surveying and reporting for approximately 5,000 people annually.
27 What the Data Show
28 The overall geometric mean blood lead levels among all participants age 1 year and older from NHANES
29 1999-2000 and 2001-2002 were 1.7 micrograms per deciliter ((ig/dL) and 1.5 (ig/dL, respectively (Exhibit
30 5-31). Adults age 20 years and older had a geometric mean lead level of 1.6 (ig/dL during the 2001-2002
31 NHANES. For this same period males and females had a geometric mean lead level of 1.8 (ig/dL and 1.2
32 (ig/dL, respectively. For non-Hispanic blacks, Mexican Americans, and non-Hispanic whites during
33 2001-2002 the geometric mean lead levels were 1.7, 1.5, and 1.4 (ig/dL, respectively. The geometric
34 mean blood levels among every age, race, and ethnic group, as well as for both males and females,
35 declined in the most recent 2001-2002 survey. Of all age groups, children age 1-5 years had the highest
36 geometric mean lead level at 1.7 (ig/dL. However, this age group also showed the largest decline between
37 1999-2000 and 2001-2002 (2.2 (ig/dL versus 1.7 (ig/dL, respectively). Children age 6-11 and 12-19 years
38 had reported geometric mean lead levels of 1.3 and 0.9 (ig/dL, respectively for the 2001-2002 survey.
39 Blood lead levels have declined steadily since NHANES surveillance of blood lead levels across the U.S.
40 began in 1976. NHANES II (1976-1980) reported a geometric mean blood lead level of 14.9 (ig/dL
41 among children age 1-5 years, the highest at risk population for lead exposure and effects and just over 88
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1 percent of this high-risk population had blood lead levels greater than or equal to 10 ug/dL (CDC, 2004a).
2 Data collected from 1991-1994 as part of NHANES III (phase 2) showed that the geometric mean blood
3 lead level for children age 1-5 years was 2.7 ug/dL with 4.4 percent of children age 1-5 years having
4 blood lead levels greater than or equal to 10 ug/dL (CDC, 2005). Children age 1-5 whose blood was
5 sampled between 1999-2002 had a geometric mean blood lead level of 1.9 ug/dL, with 1.6 percent of the
6 children having blood lead levels greater than or equal to 10 ug/dL (CDC, 2005).
Exhibit 5-31. Blood lead concentrations for the U.S population aged 1 year and older by selected
demographic groups, 1999-2002
Total, age 1 year and
alder
Sox
Male
Female
Race and ethnicity11
Black, non-Hispanic
Mexican American
White, non-Hispanic
Age group
1-5 years
6-11 years
12-1 9 years
20+ years
Survey years
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
Sample size
7,970
8,945
3,913
4,339
4,057
4,606
723
Geometric mean and selected percentiles
for blood cadmium concentrations (ug/L)a
Geometric mean
1.7
1.5
2.0
1.8
1.4
1.2
1.9
1.7
1.8
1.5
1.6
1.4
2.2
1.7
1.5
1.3
1.1
0.9
1.8
1.6
50th
1.6
1.4
1.8
1.7
1.3
1.1
1.7
1.6
1.8
1.5
1.6
1.4
2.2
1.5
1.3
1.1
1.0
0.8
1.7
1.6
75th
2.4
2.2
2.9
2.7
1.9
1.8
2.8
2.5
2.7
2.2
2.4
2.1
3.3
2.5
2.0
1.6
1.4
1.2
2.5
2.2
90th
3.8
3.4
4.4
3.9
3.0
2.6
4.2
4.2
4.2
3.6
3.6
3.1
4.8
4.1
3.3
2.7
2.3
1.9
3.9
3.6
95th
4.9
4.4
6.0
5.3
4.0
3.6
5.7
5.7
5.8
5.4
5.0
4.1
7.0
5.8
4.5
3.7
2.8
2.7
5.2
4.6
'Refer to CDC 2005 for confidence intervals for reported values.
bdther racial and ethnic groups are included in the "total" only.
Data source: 2005. Data collected by the National Health and Nutrition Examination Survey (NHANES)
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1 Indicator Limitations
2 • Because the data from NHANES 1999-2000 and 2001 -2002 represent only two survey
3 periods, changes in estimates between the two time periods do not necessarily reflect a trend.
4 Earlier data sets are available (e.g., NHANES III), but the data are not directly comparable to
5 NHANES 1999-2002. When CDC releases additional survey results (e.g., 2003-2004) it will
6 become possible to more fully evaluate trends (CDC, 2002, 2004b).
7 • The measurement of lead or any other environmental chemical in a person's blood or urine
8 does not by itself mean that the chemical has caused or will cause harmful effects in that
9 person.
10 Data Source
11 Data used for this indicator were extracted from two CDC reports that present results of the ongoing
12 National Health and Nutrition Examination Survey (CDC, 2004a and 2005). The underlying laboratory
13 data supporting CDC's reports are available online in SAS® transport file format at
14 http: //www .cdc. gov/nchs/about/maj or/nhanes/datalink .htm.
15 References
16 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
17 environmental chemicals. NCEH publication no. 05-0570. Accessed September 9, 2005.
18
19 CDC (Centers for Disease Control and Prevention). 2004a. Children's blood lead levels in the United
20 States. Accessed October 11, 2005.
21 CDC (Centers for Disease Control and Prevention). 2004b. NHANES analytic guidelines. June 2004
22 version. Accessed October 21, 2005.
23
24 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
25 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
26
27 CDC (Centers for Disease Control and Prevention). 1991. Preventing lead poisoning in young children.
28 Accessed November 21, 2004.
30 Nadakavukaren, A. 2000. Our global environment: a health perspective. Fifth ed. Prospect Heights, IL:
31 Waveland Press, Inc.
32 NRC (National Research Council). 1993. Measuring lead exposure in infants, children, and other
33 sensitive populations. Washington, DC: National Academies Press.
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NDICATOR: Blood Mercury L
2 Mercury is a naturally occurring metal. However, through many industrial processes (e.g., chemical
3 manufacturing operations, coal combustion), mercury is widespread and persistent in the environment. It
4 is found in elemental form and in various organic compounds and complexes. Methylmercury (an organic
5 form) can accumulate in the food chain in aquatic systems and lead to high concentrations in predatory
6 fish. Consumption of contaminated fish is the major source of human exposure to methylmercury in the
7 United States (NRC, 2000).
8 The human health effects of mercury are diverse and depend on the forms of mercury encountered and the
9 severity and length of exposure. Fetuses and children may be more susceptible to mercury than adults,
10 with concern for the occurrence of developmental and neurological health effects (NRC, 2000). Prenatal
11 exposures interfere with the growth and migration of neurons and have the potential to cause irreversible
12 damage to the developing central nervous system.
13 This indicator quantifies the blood mercury levels (includes organic and inorganic) among U.S. women
14 age 16-49 years and children age 1-5 years, using data from the 1999-2002 National Health and Nutrition
15 Examination Survey (NHANES). NHANES does not report blood mercury data for adult males.
16 NHANES is a series of surveys conducted by CDC's National Center for Health Statistics (NCHS) that is
17 designed to collect data on the health and nutritional status of the civilian, non-institutionalized U.S.
18 population using a complex, stratified, multistage, probability-cluster design. CDC's National Center for
19 Environmental Health (NCEH) conducted the laboratory analyses for the biomonitoring samples.
20 Beginning in 1999, NHANES became a continuous and annual national survey. Data for 1999-2000 and
21 2001-2002 are presented here as a baseline with the intent of reporting trends across time as more data
22 become available in the future.
23 What the Data Show
24 Exhibit 5-32 presents the geometric mean and four percentiles of blood mercury for selected populations
25 sampled during NHANES 1999-2000 and 2001-2002. For women age 16-49 years there was a small
26 decline in geometric mean blood mercury levels from 1999-2000 and 2001-2002 (1.0 and 0.8 micrograms
27 per deciliter [|ig/L] respectively). Decreases occurred for each of the four percentiles, but were most
28 pronounced at the 90th and especially 95th percentiles. 5.7 percent of women tested between 1999 and
29 2002 had mercury levels measured between 5.8 and 58 (ig/L. For children age 1-5 years the geometric
30 mean remained the same at 0.3 (ig/L.
31 When the geometric means are stratified across three racial/ethnic groups, black, non-Hispanic women
32 age 16-49 had the highest levels during both the 1999-2000 and 2001-2002 surveys (1.4 and 1.1 (ig/L
33 respectively), followed by white, non-Hispanics (0.9 and 0.8 (ig/L respectively), and Mexican Americans
34 (0.8 and 0.7 (ig/L respectively). Among children age 1-5 years, black, non-Hispanics have the highest
35 geometric mean between 1999 and 2002 (0.50 (ig/L), followed by Mexican Americans (0.35 (ig/L) and
36 white, non-Hispanics (0.29 (ig/L) (CDC, 2004a).
37
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Exhibit 5-32. Blood mercury concentrations for U.S. women age 16-49 years and children (male and
female) age 1-5 years by selected demographics, 1999-2002
Geometric mean and selected percentiles
for mercury concentrations (|i9/L)a
Women age 16-49 years
Total, women age
16-49 years
Race and ethnicity
Black, non-Hispanic
Mexican American
White, non-Hispanic
Children age 1-5 years
Total, children age
1-5 years
Sex
Male
Female
Race and ethnicity
Black, non-Hispanic
Mexican American
White, non-Hispanic
Survey years
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2002
1999-2002
1999-2002
Sample size
1,709
1,928
370
436
579
527
588
806
705
872
387
440
318
432
424
526
447
Geometric mean
1.0
0.8
1.4
1.1
0.8
0.7
0.9
0.8
0.3
0.3
0.32
0.31
0.38
0.33
0.50
0.35
0.29
Bfllh
0.9
0.7
1.3
1.1
0.9
0.7
0.9
0.8
0.3
0.3
0.2
0.3
0.2
0.3
0.47
0.28
0.20
75th
2.0
1.7
2.6
1.8
1.4
1.1
1.9
1.5
0.5
0.7
0.5
0.6
0.8
0.7
0.88
0.63
0.49
90th
4.9
3.0
4.8
3.2
2.6
2.1
5.0
3.0
1.4
1.2
1.1
1.3
1.6
1.3
1.5
1.4
1.2
95th
7.1
4.6
5.9
4.1
4.0
3.5
6.9
4.6
2.3
1.9
2.1
1.7
2.1
1.7
2.4
1.9
1.8
aRefer to CDC, 2005, for confidence intervals for reported values.
Data source: CDC, 2004 and 2005. Data collected by the National Health and Nutrition Examination Survey (NHANES).
1 Indicator Limitations
2
3
4
5
6
7
• Because the data from NHANES 1999-2000 and 2001 -2002 represent only two survey
periods, changes in estimates between the two time periods do not necessarily reflect a trend.
When CDC releases additional survey results (e.g., 2003-2004) it will become possible to
more fully evaluate trends (CDC, 2002, 2004b).
• The measurement of mercury or any other environmental chemical in a person's blood or
urine does not by itself mean that the chemical has caused or will cause harmful effects in
that person.
• Generally recognized guidelines for blood levels of mercury have not been established.
10 Data Sources
11 Data used for this indicator were extracted from two CDC reports that present results of the ongoing
12 National Health and Nutrition Examination Survey (CDC, 2004a and 2005). The underlying laboratory
13 data supporting CDC's reports are available online in SAS® transport file format at
14 htto: //www .cdc. gov/nchs/about/mai or/nhanes/datalink .htm.
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1 References
2 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
3 environmental chemicals. NCEH publication no. 05-0570. Accessed September 9, 2005.
4
5 CDC (Centers for Disease Control and Prevention). 2004a. Blood mercury levels in young children and
6 childbearing-aged women—United States, 1999-2002. MMWR 53:1018-1020. Accessed December 2,
7 2004.
8 CDC (Centers for Disease Control and Prevention). 2004b. NHANES analytic guidelines. June 2004
9 version. Accessed October 21, 2005.
10
11 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
12 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
13
14 NRC (National Research Council). 2000. Toxicological effects of methylmercury. Washington, DC:
15 National Academies Press.
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INDICATOR: Blood Cadmium Level
2 Cadmium is a metal that is usually found in nature combined with oxygen, chlorine, or sulfur. Cadmium
3 enters the environment from the weathering of rocks and minerals that contain cadmium. Exposure to
4 cadmium can occur in occupations such as mining or electroplating, where cadmium is produced or used.
5 Cadmium exposure can also occur from exposure to cigarette smoke (CDC, 2005).
6 Cadmium and its compounds are toxic to humans and animals. Once absorbed into the human body,
7 cadmium can accumulate in the kidneys and remain in the body for decades. Chronic exposure to
8 cadmium may result in serious kidney damage. Osteomalacia, a bone disorder similar to rickets, is also
9 associated with long-term ingestion of cadmium. Acute airborne exposure, as occurs from welding on
10 cadmium-alloy metals, can result in swelling (edema) and scarring (fibrosis) of the lungs (CDC, 2005).
11 This indicator reflects blood cadmium concentrations in (ig/L for the United States population, age 1 year
12 and older, as measured in the 1999-2002 National Health and Nutrition Examination Survey (NHANES).
13 NHANES is a series of surveys conducted by the Centers for Disease Control and Prevention's (CDC)
14 National Center for Health Statistics (NCHS) that is designed to collect data on the health and nutritional
15 status of the civilian, non-institutionalized U.S. population using a complex, stratified, multistage,
16 probability-cluster design. CDC's National Center for Environmental Health (NCEH) conducted the
17 laboratory analyses for the biomonitoring samples. Beginning in 1999, NHANES became a continuous
18 and annual national survey; biomonitoring for certain environmental chemicals also was implemented.
19 Data for 1999-2000 and 2001-2002 are presented here as a baseline with the intent of reporting trends
20 across time as more data become available in the future.
21 What the Data Show
22 Exhibit 5-33 presents the geometric means and selected percentiles for blood cadmium among
23 participants age 1 year and older from NHANES 1999-2000 and 2001-2002. During the 2001-2002
24 survey the overall geometric mean blood cadmium level was not calculated because of the high number of
25 samples that were below the method's limit of detection. However, the blood cadmium levels at the four
26 different percentiles (50th, 75th, 90th, and 95th) are very similar across the two survey periods, with
27 levels ranging between 0.3 and 1.4 (ig/L. The blood cadmium measurements were similar among males
28 and females as well as among the racial or ethnic groups sampled across both time periods.
29 During the 1999-2000 survey the overall geometric mean among participants age 20 years or older was
30 slightly higher (0.5 (ig/L) than the geometric mean among the 12-19 year age group (0.3 (ig/L).
31 Compared to the other age groups, those older than 20 years had higher cadmium levels for each of the
32 four selected percentiles during both survey periods. During the 1999-2000 survey, approximately one-
33 half of all participants under the age of 12 had non-detectable blood cadmium concentrations. This
34 proportion increased to about 90 percent during the 2001-2002 survey.
35
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Exhibit 5-33. Blood cadmium concentrations for the U.S. population age 1 year and older by selected
demographic groups, 1999-2002
Geometric mean and selected percentiles
for cadmium concentrations (|ig/L)a b> °
Survey years
1999-2000
2001-2002
Sample size
7,970
8,945
3,913
4,339
4,057
4,606
Geometric mean
0.4
NC
0.4
NC
0.4
NC
0.4
NC
0.4
NC
0.4
NC
SO'"
0.3
0.3
0.4
0.3
0.3
0.3
0.3
-------
1 Data Sources
2 Data used for this indicator were extracted from the CDC report that presents results of the ongoing
3 National Health and Nutrition Examination Survey (CDC, 2005). The underlying laboratory data
4 supporting CDC's report are available online in SAS® transport file format at
5 http: //www .cdc. gov/nchs/about/maj or/nhanes/datalink .htm.
6 References
7 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
8 environmental chemicals. NCEH publication no. 05-0570.
9
10 CDC (Centers for Disease Control and Prevention). 2004. NHANES analytic guidelines. June 2004
11 version. Accessed October 21, 2005.
12
13 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
14 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
15
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NDICATOR: Blood Persistent Organic Pollutants Lev
2 Persistent organic pollutants (POPs) are manmade organic chemicals that remain in the environment for
3 years or decades. Some POPs are toxic; others are not. Toxic POPs are of special concern because they
4 often remain toxic for decades or longer. The more persistent a toxic chemical is, the greater the
5 probability for human exposure over time. Because they circulate globally long after being released into
6 the environment, POPs are often detected in locations far from the original source (U.S. EPA, 2004a).
7 One of the major sources of POPs exposure among the general population is food. Food contamination
8 begins with contaminated soil and/or plants but is of greatest concern to humans as the POPs move up the
9 food chain into animals. Because POPs typically accumulate in fatty tissue and are slow to be
10 metabolized, they bioconcentrate (i.e., increase in concentration) with each trophic level. Therefore, foods
11 such as dairy products, eggs, animal fats, and some types offish are more likely to contain greater
12 concentrations of POPs than fruits, vegetables, and grains. POPs have been linked to adverse health
13 effects such as cancer, nervous system damage, reproductive disorders, and disruption of the immune
14 system in both humans and animals (U.S. EPA, 2004a).
15 This indicator presents data from CDC's National Health and Nutrition Examination Survey (NHANES)
16 1999-2000 and 2001-2002. NHANES is a series of surveys conducted by CDC's National Center for
17 Health Statistics (NCHS) that is designed to collect data on the health and nutritional status of the
18 civilian, non-institutionalized U.S. population using a complex, stratified, multistage, probability-cluster
19 design. CDC's National Center for Environmental Health (NCEH) conducted the laboratory analyses for
20 the biomonitoring samples. Beginning in 1999, NHANES became a continuous and annual national
21 survey; biomonitoring for certain environmental chemicals also was implemented. These data are
22 presented here as a baseline with the intent of reporting trends over larger time periods in the future.
23 Blood levels of POPs or their metabolites were measured in NHANES participants age 12 years or older.
24 This indicator includes the following three broad classes of POPs:
25 • Organochlorine pesticides
26 • Polychlorinated dibenzo-p-dioxins (dioxins) and polychlorinated dibenzo-p-furans (furans)
27 • Polychlorinated biphenyls (PCBs)
28 Organochlorine pesticides were first introduced in the 1940s. Because of their environmental
29 persistence, EPA banned most uses of these chemicals during the 1970s and 1980s. However, many other
30 countries still produce and/or use Organochlorines. These fat-soluble chemicals are most commonly
31 absorbed through fatty foods. These pesticides are associated with effects to the central nervous system at
32 acute exposure levels and potential carcinogenic effects with long-term exposure (Reigart and Roberts,
33 1999). This indicator includes eight Organochlorine pesticides that were measured in NHANES 1999-
34 2000 and 2001-2002; data for three of these pesticides (aldrin, dieldrin, and endrin) first became available
35 with the release of results from NHANES 2001-2002 (CDC, 2005).
36 • Aldrin and dieldrin. These two pesticides were widely used from the 1950s until 1970 when
37 EPA prohibited most agricultural uses. However, they continued to be used to control
38 termites until that use was prohibited in 1987. Aldrin rapidly converts to dieldrin in the
39 environment or after being ingested or absorbed into the body. Dieldrin is more persistent and
40 often accumulates in fatty tissues (CDC, 2005).
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1 • Chlordane and heptachlor. EPA banned these pesticides in 1988. Within the body,
2 chlordane is metabolized to oxychlordane and fra«s-nonachlor, and heptachlor is metabolized
3 to heptachlor epoxide (CDC, 2003). Chlordane was commonly used against termites and on
4 some agricultural crops and heptachlor was used primarily against soil insects and termites
5 (Ritter et al., n.d.).
6 • DDT. Dichlorodiphenyltrichlorethane, or DDT, was banned in the United States in 1973 but
7 is still produced in other countries, where it is used primarily to control mosquitoes. In the
8 body or the environment, DDT breaks down to DDE (dichlorodiphenyldichloroethane), a
9 more persistent chemical. DDT or DDE in the human body may reflect either a relatively
10 recent exposure or cumulative past exposures (CDC, 2005).
11 • Endrin. Endrin is a stereoisomer (i.e., a molecule that is a mirror image of another molecule
12 with the same molecular formula) of dieldrin. Endrin production was discontinued in 1986
13 primarily because of its persistence in the environment. Unlike many other organochlorine
14 pesticides, endrin does not readily accumulate in body tissues and is metabolized and
15 eliminated from the body relatively quickly (CDC, 2005).
16 • Hexachlorobenzene (HCB) was commonly used as a pesticide until 1965. HCB was also
17 used in the past as a fungicide to protect wheat seeds, and for a variety of industrial purposes,
18 including rubber, aluminum, dye production and wood preservation (U.S. EPA, 2004b). EPA
19 canceled registered use in 1984; however, HCB is still formed as a by-product during
20 manufacturing of other chemicals and pesticides (U.S. EPA, 2004b).
21 • Mirex has not been produced or used in the United States since 1978. It was used primarily
22 in the southern United States to control fire ants. The primary source of exposure is dietary,
23 most often through consumption offish (U.S. EPA, 2004c).
24 Dioxins and furans are similar classes of chlorinated aromatic chemicals, usually generated as pollutants
25 or by-products. In the environment, dioxins and furans occur as a mixture of about 20 compounds (termed
26 "congeners"). Half-lives of these congeners range from roughly 3 to 19 years (CDC, 2005). Human
27 exposure occurs primarily through food; other sources of exposure include industrial accidents, burning of
28 PCBs contaminated with dioxins and furans, burning of many plastics such as PVC, and spraying or
29 unintended releases of contaminated herbicides such as Agent Orange. The detection of dioxins and
30 furans in human blood can reflect either recent or past exposures (CDC, 2005).
31 Human health effects associated with dioxins and furans are wide-ranging. The effects of individual
32 congeners are difficult to determine since most people are exposed to mixtures of several congeners.
33 However, overall health effects include liver disorders, fetal injury, porphyria (a condition resulting in
34 abnormal metabolic function), elevated lipid levels, chloracne, hormonal changes, neurologic damage,
35 and immunogenic changes. The dioxin congener TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) is the most
36 toxic form of dioxin and it is classified as a known human carcinogen (IARC, 1997). The half-life of
37 TCDD is estimated to be around 7 years (CDC, 2005).
38 Polychlorinated biphenyls (PCBs) are chlorinated aromatic hydrocarbons used in a variety of industries
39 as electrical insulating and heat exchange fluids. PCBs are composed of mixtures of up to 209 different
40 chlorinated congeners. United States production of PCBs peaked in the early 1970s; PCBs were banned in
41 1979. Sources of exposure forthe general population include releases from waste sites and fires involving
42 transformers, ingestion of foods contaminated by PCBs, and migration from packaging materials. PCBs
43 typically accumulate in fatty tissues (ATSDR, 2000).
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1 The detection of PCBs in human blood can reflect either recent or past exposures. PCBs with higher
2 degrees of chlorination persist in the human body from several months to years after exposure. Coplanar
3 and mono-ortho substituted PCBs exhibit health effects similar to dioxins. The human health effects of
4 PCBs include changes in liver function, elevated lipids, and gastrointestinal cancers (CDC, 2005).
5 What the Data Show
6 Organochlorine pesticides. Exhibit 5-34 presents the lipid-adjusted and whole weight geometric means
7 and four percentile values for selected organochlorine pesticide metabolites measured in blood. The
8 overall geometric mean for p,p'-DDE (metabolite for DDT) during the 1999-2000 survey was 260
9 nanograms per gram (ng/g), compared to 295 ng/g in 2001-2002. During the most recent survey (2001-
10 2002), the geometric mean for trans-nonachlor (metabolite for chlordane) was 17 ng/g, compared with
11 18.3 ng/g in 1999-2000. Aldrin, dieldrin, endrin, heptachlor epoxide (metabolite for heptachlor), HCB,
12 and mirex were not measured with sufficient frequency above the limit of detection to calculate a
13 geometric mean.
14 Geometric mean blood concentrations ofp, p '-DDE were compared among demographic groups after
15 adjustment for the covariates of race/ethnicity, age, and gender. For samples collected between 1999 and
16 2002, the 12-19 year age group had less than half the blood DDE level compared to the 20 years or older
17 age group (CDC, 2005). The adjusted geometric mean level in Mexican Americans was 652 ng/g during
18 the most recent survey, more than two and one-half times higher than levels in non-Hispanic whites and
19 two times higher than levels in non-Hispanic blacks. It is unknown whether differences in geometric
20 mean blood DDE concentrations between different age groups or racial/ethnic groups represent
21 differences in exposure, body size relationships, or metabolism (CDC, 2005) (data not shown).
22 Dioxins and furans. In the U.S., quantifiable emissions of dioxin-like compounds from all known
23 sources have decreased by an estimated 89 percent between 1987 and 2000 (U.S. EPA, 2006). Values
24 reported in NHANES 1999-2000 and 2001-2002 support that estimated decline (CDC, 2005). For
25 example, among the entire NHANES 1999-2000 sample population, TCDD (generally considered the
26 most toxic dioxin) was detected less than one percent of the time (CDC, 2003). During 2001-2002, only a
27 small number of the dioxin and furan congeners analyzed were detected frequently enough for geometric
28 means to be calculated (Exhibit 5-35). TCDD continued to be among the list of congeners analyzed in
29 NHANES 2001-2002, though only the 95th percentiles for women and non-Hispanic blacks could be
30 characterized (6.4 and 7.4 picograms/gram [pg/g] TCDD lipid-adjusted, respectively) (data not shown).
31 From NHANES 1999-2000, none of the six dioxin or nine furan congeners measured in the blood were
32 detected with sufficient frequency to calculate a geometric mean.
33 In general, the more highly chlorinated dioxin and furan congeners were the main contributors to the
34 human body burden. The higher concentrations of these congeners in human samples are a result of their
35 greater persistence in the environment, bioaccumulation in the food chain, resistance to metabolic
36 degradation, and greater solubility in body fat (CDC, 2005).
37 PCBs. During the NHANES 1999-2000 subsample period, none of the 3 coplanar and 25 other PCB
38 congeners were measured in blood with sufficient frequency above the limit of detection to calculate a
39 geometric mean. The frequency of detection of the eight mono-ortho substituted PCBs ranged from 2 to
40 47 percent (CDC, 2003). Coplanar PCB congeners 169 and 126, which exhibit dioxin-like toxicity, had a
41 detection rate above 5 percent (CDC, 2003). In the 2001-2002 survey, a total of 12 dioxin-like PCB
42 compounds, three coplanar PCBs and nine mono-ortho-substituted PCBs, were measured in blood. In
43 addition, a total of 25 non dioxin-like PCBs were also included in the 2001-2002 NHANES analysis.
44 However, only two coplanar PCBs and three non-dioxin-like PCB compounds were detected with
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1 sufficient frequency to calculate a geometric mean (Exhibit 5-35). Although some PCB congeners were
2 detected with greater frequency during the 2001-2002 survey compared to 1999-2000, this may, in part,
3 be attributed to improved limits of detection in NHANES 2001-2002 (CDC 2005). After adjusting for a
4 number of covariates (e.g., age, gender, blood cotinine, and lipid level), there were some differences
5 observed in the concentrations of different PCB congeners between different demographic subgroups.
6 However, it is unknown whether these differences represent differences in exposure, pharmacokinetics, or
7 the relationship of dose per body weight (CDC, 2005).
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Exhibit 5-34. Blood concentrations of selected organochlorme pesticide metabolites for the U.S.
population age 12 years and older, llpld-adjusted and whole weight, 1999-2002
Geometric mean and selected percentiles
for organochlorine pesticide metabolite concentrations (ng/g)a>b'c
Aldrin
Lipid-adjusted
Whole weight
Chlordane
Oxychlordane
Lipid-adjusted
2001-2002
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
trans-Nonachlor
Lipid-adjusted
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
Lipid-adjusted
Whole weight
1999-2000
2001-2002
1999-2000
1999-2000
2001-2002
1999-2000
2001-2002
Dieldrin
Lipid-adjusted
Whole weight
2001-2002
2001-2002
2001-2002
2001-2002
Lipid-adjusted
Whole weight
See notes at end of table.
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5-89
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Exhibit 5-34 (continued). Blood concentrations of selected organochlorme pesticide metabolites for the
U.S. population age 12 years and older, lipid-adjusted and whole weight, 1999-2002
Geometric mean and selected percentiles
for organochlorine pesticide metabolite concentrations (in ng/g)a'bpC
Survey years
Heptachlor
Heptachlor epoxide
1999-2000
2001-2002
1999-2000
2001-2002
Lipid-adjusted
Whole weight
Haxachlorobenzone (HCB)
Lipid-adjusted
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
aNC = not calculated; the proportion of results below the limit of detection was too high to provide a valid result.
b
-------
Exhibit 5-35. Blood concentrations of selected polycnlorinated dibenzo-p-dioxms (dioxms),
polychlorinated dibenzofurans (furans), and dioxin-like polychlorinated biphenyls (RGBs) for the U.S.
population age 20 years and older, lipid-adjusted and whole weight, 1999-2002"b
Geometric mean and selected percentiles
tor dioxin, furan, and PCB concentrations04
Dioxins (pg/g)
1,2,3,4,6,7,8,9-OCDD
1999-2000
2001-2002
1999-2000
2001-2002
1,2,3,4,6,7,8-HpCDD
Lipid-adjusted
1999-2000
2001-2002
1999-2000
2001-2002
1,2,3,6,7,8-HxCDD
1999-2000
2001-2002
1999-2000
2001-2002
1,2,3,4,6,7,8-HpCDF
Lipid-adjusted
1999-2000
2001-2002
1999-2000
2001-2002
PCBs (unils vary)
PCB 126 (pg/g)
Lipid-adjusted
1999-2000
2001-2002
1999-2000
2001-2002
PCBs (unils vary)
PCB 169 (pg/g)
1999-2000
2001-2002
1999-2000
2001-2002
Lipid-adjusted
Whole weight
See notes at end of table.
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5-91
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Exhibit 5-35 (continued). Blood concentrations of selected polychlorinated dibenzo-p-dioxins (dioxins)
polychlorinated dibenzofurans (furans), and dioxin-like polychlorinated biphenyls (PCBs) for the U.S.
population age 20 years and older, lipid-adjusted and whole weight, 1999-2002ab
Geometric mean and selected percentiles
for dioxin, furan, and PCB concentrations0 de
Survey years Sample size Geometric mean 50tn
75th
90th
95th
PCBs (units vary)
PCB 138 & 158 (ng/g)
Lipid-adjusted
Whole weight
PCB 153 (ng/g)
Lipid-adjusted
Whole weight
PCB 180 (ng/g)
Lipid-adjusted
Whole weight
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1,261
1,545
1,261
1,545
1,258
1,549
1,258
1,549
1,257
1,547
1,257
1,547
NC
23.3
NC
0.15
NC
32.6
NC
0.21
NC
23
NC
0.15
-------
1 References
2 ATSDR (Agency for Toxic Substances and Disease Registry). 2000. Toxicological profile for
3 polychlorinated biphenyls (PCBs). Atlanta, GA: U.S. Department of Health and Human Services, Public
4 Health Service.
5 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
6 environmental chemicals. NCEH publication no. 05-0570. Accessed September 9, 2005.
7
8 CDC (Centers for Disease Control and Prevention). 2004. NHANES analytic guidelines. June 2004
9 version. Accessed October 21, 2005.
10
11 CDC (Centers for Disease Control and Prevention). 2003. Second national report on human exposure to
12 environmental chemicals. NCEH publication 02-0716. Accessed November 21, 2004.
13 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
14 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
15
16 IARC (International Agency for Research on Cancer). 1997. Polychlorinated dibenzo-para-dioxins and
17 polychlorinated dibenzofurans. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans
18 vol. 69. Lyon, France.
19 Reigart, J.R., and J.R. Roberts. 1999. Recognition and management of pesticide poisonings. Prepared for
20 U.S. EPA. Accessed April 11, 2005.
21
22 Ritter, L., K.R. Solomon, J. Forget, M. Stemeroff, and C. O'Leary. n.d. Persistent organic pollutants. The
23 International Programme on Chemical Safety (IPCS) within the framework of the Inter-Organization
24 Programme for the Sound Management of Chemicals (IOMC).
25
26 U.S. EPA. 2006. Inventory of sources of environmental releases of dioxin-like compounds in the United
27 States: the year 2000 update. EPA/600/P-03/002a. Washington, DC. [link will be provided at future date]
28 U.S. EPA. 2004a. Pesticides: regulating pesticides—persistent organic pollutants (POPs). Updated
29 August 2004. Accessed December 7, 2004.
30 U.S. EPA. 2004b. Hexachlorobenzene. Updated December 2004. Accessed December 7, 2004.
31
32 U.S. EPA. 2004c. Mirex. Updated December 2004. Accessed December 7, 2004.
33
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NDICATOR: Urinary Pesticide Le1
2 Pesticides are chemicals or biological agents that kill plant or animal pests and may include herbicides,
3 insecticides, fungicides, and rodenticides. More than one billion pounds of pesticides are used in the
4 United States each year to control weeds, insects, and other organisms that threaten or undermine human
5 activities (Aspelin, 2003). Some of these compounds can be harmful to humans if ingested, inhaled, or
6 otherwise contacted in sufficient quantities. The primary routes of exposure for the general population are
7 ingestion of a treated food source and contact with applications in or near residential sites. Herbicide
8 exposure may also result from contaminated water. Those who manufacture, formulate, and/or apply
9 these chemicals may also be occupationally exposed.
10 This indicator reports the results of human biomonitoring for three classes of non-persistent insecticides
11 and three classes of herbicides, which can be measured through metabolites that result from the chemical
12 breakdown of the pesticide within the body. Measurement of non-persistent pesticide metabolites in urine
13 typically reflects recent exposure (i.e., in the last few days) due to the short time these metabolites remain
14 within the body (CDC, 2005).
15 The three classes of insecticides covered by this indicator are carbamates, organophosphates (OPs), and
16 pyrethroids. Carbamate insecticides have a wide variety of uses, which include applications on
17 agricultural crops, residential lawns and gardens, and golf courses. Carbamate insecticides do not persist
18 long in the environment, so they have a low potential for bioaccumulation. Organophosphates are used to
19 control a broad spectrum of insects and account for about half of all insecticides used in the United States.
20 Although organophosphates are still used for insect control on many food crops, most residential uses are
21 being phased out in the United States. Pyrethroids are synthetic analogues of pyrethrins, which are natural
22 chemicals found in chrysanthemum flowers. All three groups are neurotoxicants that act by
23 overstimulating the nervous system of exposed organisms. Symptoms of exposure to pesticides in these
24 classes may include muscle weakness or paralysis, difficulty breathing, difficulty concentrating, impaired
25 coordination, and memory loss (CDC, 2005)
26 The three herbicide classes discussed here are licensed for both commercial and restricted use. Restricted
27 use products can only be applied by certified applicators or under the supervision of such an applicator
28 (U.S. EPA, 2003). The herbicide groups are: chlorphenoxy acids, triazines, and chloroacetamides.
29 Symptoms of acute high dose exposure to these herbicides may include skin and mucosal irritation as
30 well as burning sensations in the nasopharynx and chest if inhaled (Reigart and Roberts, 1999).
31 This indicator presents pesticide urinary metabolite data collected as part of CDC's National Health and
32 Nutrition Examination Survey (NHANES). NHANES is a series of surveys conducted by CDC's National
33 Center for Health Statistics (NCHS) that is designed to collect data on the health and nutritional status of
34 the civilian, non-institutionalized U.S. population using a complex, stratified, multistage, probability-
35 cluster design. CDC's National Center for Environmental Health (NCEH) conducted the laboratory
36 analyses for the biomonitoring samples. Beginning in 1999, NHANES became a continuous and annual
37 national survey; biomonitoring for certain environmental chemicals also was implemented. Data for
38 1999-2000 and 2001-2002 are presented here as a baseline with the intent of reporting trends over larger
39 time periods in the future. Carbamates, organophosphates, and herbicides were measured as part of
40 NHANES 1999-2000; urinary levels of pyrethroids were added during the NHANES 2001 -2002 survey.
41 This indicator presents data for a subsample of survey participants age 6 to 59 years. NHANES also
42 measured levels of a class of persistent pesticides, the organochlorine pesticides, which are not discussed
43 here but can be found under the Indicator "Blood Persistent Organic Pollutants Level."
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1 What the Data Show
2 Carbamates. Exhibit 5-36 presents the geometric means and four percentile values for unadjusted and
3 creatinine-adjusted urinary concentrations of the carbamate pesticide metabolites. Of the three metabolites
4 presented, only 1-naphthol was detected with sufficient frequency to calculate a measurable geometric
5 mean, which was 1.70 (ig/L and 1.52 migrograms per gram (|ig/g) (creatinine-adjusted).
6 Organophosphates. NHANES 1999-2000 and 2001-2002 measured urinary concentrations of dialkyl
7 phosphates, which are the primary metabolites of many organophosphate compounds. Exhibit 5-37
8 presents the geometric means and four percentile values for urinary concentrations and creatinine-
9 adjusted urinary concentrations of these metabolites. Only three of the six urinary dialkyl phosphates
10 presented (dimethylthiophosphate, diethylphosphate, and diethylthiophosphate) were measured with
11 sufficient frequency above the limit of detection to calculate a geometric mean. The geometric means for
12 those metabolites were 1.82 (ig/L (1.64 (ig/g creatinine), 1.03 (ig/L (0.92 (ig/g creatinine), and 0.46 (ig/L
13 (0.45 (ig/L creatinine), respectively.
14 Pyrethroids. Pyrethroid (parent and metabolite) compounds were not included in the NHANES 1999-
15 2000 list of analytes measured in urine. During the 2001-2002 NHANES, however, five pyrethroid
16 urinary metabolites were measured in urine samples from a subgroup of participants. Only one of these
17 metabolites, 3-phenoxybenzoic acid was measured with sufficient frequency above the limit of detection
18 to calculate a geometric mean. The geometric mean concentration of this metabolite measured in urine
19 was 0.32 (ig/L (Exhibit 5-38).
20 Herbicides. During the 1999-2000 survey, none of the direct metabolites of the three primary classes of
21 herbicide were detected in urine with sufficient frequency above the limit of detection to calculate a
22 geometric mean; therefore, data are not displayed. The metabolites 2,4,5-trichlorophenoxyacetic acid and
23 atrazine mercapturate were detected in only 1.2 percent and 3.3 percent, respectively, of the subsample
24 (CDC, 2003). The minor metabolite 2,4-dichlorophenol had a geometric mean of 1.1 (ig/L measured in
25 urine; however, this metabolite can also be a result of metabolism of several other chemicals or a
26 byproduct in the manufacture of chemicals. The findings from the 2001-2002 survey were generally
27 consistent with earlier findings showing these metabolites to be frequently near or below the limits of
28 detection. Unlike the 1999-2000 results, 2,4-dichlorophenol samples collected during 2001-2002 were not
29 detected with sufficient frequency above the detection limit to calculate a geometric mean. However, the
30 reported concentration of this metabolite at the 75th, 90th, and 95thpercentile were higher during the 2001-
31 2002 survey than during the 1999-2000 survey (CDC, 2005).
32
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Exhibit 5-36. Urine concentrations of selected carbamate pesticide metabolites for the U.S. population
age 6-59 years, 1999-2002
Geometric mean and selected percentiles
for carbamale metabolite concentrations3
1-Napntnol
|jg/L of urine
M9/g of creatinine
1999-2000
1999-2000
2-lsopropoxyphenol
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
NC = not calculated; the proportion of results below the limit of detection was too high to provide a valid result.
b
-------
Exhibit 5-37. Urine concentrations of selected organophosphate pesticide metabolites for the U.S.
population age 6-59 years, 1999-2002
Geometric mean and selected percentiles
or organophosphate pesticide metabolite concentrations"bc
Geometric mean 50th
Dlmetnylpnospnate
1999-2000
2001-2002
1999-2000
ug/gofcreatinine
Dimetnylthiophosphale
ug/L of urine
1999-2000
2001-2002
1999-2000
2001-2002
Dlmethyldlthlophosphate
1999-2000
2001-2002
1999-2000
2001-2002
Diethylphosphate
ug/L of urine
1999-2000
2001-2002
1999-2000
2001-2002
DlatnyltnlopnospnatB
ug/L of urine
1999-2000
2001-2002
1999-2000
2001-2002
|jg/g of creatmme
Diethyldithiophosphale
ug/L of urine
1999-2000
2001-2002
1999-2000
2001-2002
NC = rot calculated; the proportion of results below the limit of detection was too high to provide a valid result.
b
-------
Exhibit 5-38. Urine concentrations of selected pyrethroid pesticide metabolites for the U.S. population
age 6-59 years, 2001-2002
Geometric mean and selected percentiles
of pyrelhroid pesticide metabolite concentrations*
Survey years Sample size Geometric mean 50tn
75th
4-Fluoro-3-phenoxybenzoic acid
ug/L of urine 2001-2002 2,539
ug/g of creatinine 2001-2002 2,538
cis-3-(2,2-Dichlorovinyl)-2,2-dimethyl cyclopropane carboxylic acid
ug/L of urine 2001-2002 2,539
ug/g of creatinine 2001-2002 2,538
Irans-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid
ug/L of urine 2001-2002 2,525
2001-2002
ug/g of creatinine
2,524
cis-3-(2,2-Dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid
ug/L of urine
ug/g of creatinine
3-Phenoxybenzoic acid
Mg/L of urine
ug/g of creatinine
2001-2002
2001-2002
2001-2002
2001-2002
2,539
2,538
2,539
2,538
NC
NC
NC
NC
NC
NC
NC
NC
0.32
0.32
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1 Data Sources
2 Data used for this indicator were extracted from two CDC publications that present results of the ongoing
3 National Health and Nutrition Examination Survey (CDC, 2003 and 2005). The underlying laboratory
4 data supporting CDC's report are available online in SAS® transport file format at
5 http: //www .cdc. gov/nchs/about/maj or/nhanes/datalink .htm.
6 References
7 Aspelin, A.L. 2003. Pesticide usage in the United States: trends during the 20th century. Raleigh, NC:
8 Center for Integrated Pest Management, North Carolina State University.
9
10 Barr, D.B., L.C. Wilder, S.P. Caudill, A.J. Gonzalez, L.L. Needham, and J.L. Pirkle. 2004. Urinary
11 creatinine concentrations in the U.S. population: implications for urinary biological monitoring
12 measurements. Environ. Health Persp. 113:192-200. Accessed September 14, 2005.
13
14 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
15 environmental chemicals. NCEH publication no. 05-0570. Accessed September 29, 2005.
16
17 CDC (Centers for Disease Control and Prevention). 2004. NHANES analytic guidelines. June 2004
18 version. Accessed October 21, 2005.
19
20 CDC (Centers for Disease Control and Prevention). 2003. Second national report on human exposure to
21 environmental chemicals. NCEH publication 02-0716. Accessed November 21, 2004.
22 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
23 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
24
25 Reigart, J.R., and J.R. Roberts. 1999. Recognition and management of pesticide poisonings. Prepared for
26 U.S. Environmental Protection Agency. Accessed April 11, 2005.
27
28 U.S. EPA. 2003. Restricted use products (RUP) report. Accessed March 10, 2005.
29
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NDICATOR: Urinary Phthalate Le<
2 Phthalates are industrial chemicals added to many consumer products such as food packaging, plastics
3 (plastic bags, garden hoses, recreational toys, medical tubing, plastic clothes, etc.), adhesives, detergents,
4 personal-care products (such as soap, shampoo, nail polish, et), and many others. Exposure can occur
5 through food that has been in contact with phthalate containing packaging as well as direct contact with
6 products that contain phthalates.
7 Acute high dose exposure to di (2-ethylhexyl) phthalate may be associated with mild gastrointestinal
8 disturbances, nausea and vertigo (U.S. EPA, 2005). Chronic exposure has been associated with damage to
9 the liver and testes, cancer, and birth defects in animal studies. However, the extent to which these effects
10 occur in humans has not yet been fully investigated (CDC, 2005). A recent review of six phthalate
11 compounds conducted by the Center for the Evaluation of Risks to Human Reproduction summarizes the
12 increasing body of data showing reproductive and developmental toxicity from low-level exposures to
13 certain phthalate compounds as well as highlighting the critical data gaps that exist (Kavlock et al.,
14 2002a-g).
15 This indicator is based on data collected by the National Health and Nutrition Examination Survey
16 (NHANES). NHANES is a series of surveys conducted by CDC's National Center for Health Statistics
17 (NCHS) that is designed to collect data on the health and nutritional status of the civilian, non-
18 institutionalized U.S. population using a complex, stratified, multistage, probability-cluster design.
19 CDC's National Center for Environmental Health (NCEH) conducted the laboratory analyses for the
20 biomonitoring samples. Beginning in 1999, NHANES became a continuous and annual national survey;
21 biomonitoring for certain environmental chemicals also was implemented. Metabolites of phthalates are
22 measured in urine as a biomarker of phthalate exposure in the population. Data for 1999-2000 and 2001-
23 2002 are presented here as a baseline with the intent of reporting trends across time as more data become
24 available in the future.
25 What the Data Show
26 Exhibit 5-39 presents the geometric means and four percentiles for urinary concentrations and creatinine-
27 adjusted urinary concentrations of 12 selected metabolites of phthalates among a subsample of
28 participants age 6 years and older from the most current NHANES (2001-2002). Seven of the 12
29 phthalates were also previously measured in the 1999-2000 survey and are also presented in the table.
30 Mono-ethyl phthalate (metabolite for diethyl phthalate, an industrial solvent used in many products
31 including those containing fragrances) was the phthalate detected in the highest concentration during both
32 surveys (1999-2000 and 2001-2002), with a creatinine-adjusted geometric mean concentration of 163 and
33 167 (ig/g of creatinine, respectively.
34 In addition, other phthalate compounds such as mono-n-butyl phthalate (the metabolite for dibutyl
35 phthalate, an industrial solvent used in cosmetics, printing inks, insecticides), mono-benzyl phthalate
36 (metabolite for benzylbutyl phthalate, an industrial solvent used in adhesives, vinyl flooring, and car care
37 products), and mono-2-ethylhexyl phthalate (metabolite for di-2-ethylhexyl phthalate, used to produce
38 flexible plastics) were detected in urine samples. Mono-cyclohexyl phthalate, mono-n-octyl phthalate, and
39 mono-isononyl phthalate were not measured with sufficient frequency above the limit of detection to
40 calculate a geometric mean for those samples collected between 1999 and 2002.
41 During the 1999-2000 and 2001-2002 surveys, the geometric mean levels for mono-ethyl phthalate,
42 mono-n-butyl phthalate, mono-benzyl phthalate, and mon-2-ethylhexyl phthalate among specified
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1 demographic subgroups were compared after adjustment for the covariates of race/ethnicity, age, gender,
2 and urinary creatinine. For those age 6-11 years compared to the older age groups (12-19 years and 20+
3 years), urinary mono-ethyl phthalate levels were found to be lower, but urinary mono-butyl, mono-
4 benzyl, and mono-2-ethylhexyl phthalates were higher (CDC, 2005). Females tended to have a higher
5 level than males for mono-ethyl, mono-butyl, and mono-benzyl phthalates. Non-Hispanic blacks had
6 higher levels of mono-ethyl phthalate than non-Hispanic whites or Mexican Americans. (Data not
7 shown.)
Exhibit 5-39. Urine concentrations of selected phthalate metabolites in the U.S. population age 6 years
and older, 1999-2002*
Geometric mean and selected percentiles of
phthalate metabolite concentrations5'011
Survey years
Mono-methyl phthalate
Mg/L of urine 2001-2002
Mg/g of creatinine 2001-2002
Mono-isobutyl phthalate
Mg/L of urine 2001-2002
Mg/g of creatinine 2001 -2002
Mono-(2-Bthyl-5-hydroxyhexyl) phthalate
Mg/L of urine 2001-2002
Mg/g of creatinine 2001 -2002
Mono-(2-ethyl-5-oxoyhexyl) phthalate
Mg/L of urine 2001-2002
Mg/g of creatinine 2001 -2002
Mono-3-carboxypropyl phthalate
Mg/L of urine 2001-2002
Mg/g of creatinine 2001 -2002
Mono-ethyl phthalate
/L of urine 1999-2000
2001-2002
. , t. . 1999-2000
Mg/g of creatinine
Mono-n-butyl phthalate
1999-2000
™ ° Urme 2001-2002
, , . . 1999-2000
Mg/g of creatinine
Mono-benzyl phthalate
^ of urine • ~
Mg/g of creatinine
Mono-cyclohexyl phthalate
1999-2000
1999-2000
Mg/g of creatinine m^m
See notes at end of table.
Sample size Geometric mean
2,782
2,772
2,782
2,772
2,782
2,772
2,782
2,772
2,782
2,772
2,536
2,782
2,536
2,772
2,541
2,782
2,541
2,772
2,541
2,782
2,541
2,772
2,541
2,782
2,541
2,772
1.15
1.08
2.71
2.53
20.0
18.8
13.5
12.6
2.75
2.57
179
178
163
167
24.6
18.9
22.4
17.8
15.3
15.1
14.0
14.1
NC
NC
NC
NC
50lh
1.50
1.33
2.60
2.44
20.1
16.6
14.0
11.2
3.00
2.45
164
169
141
147
26.0
20.4
21.9
17.4
17.0
15.7
13.3
13.5
-------
Exhibit 5-39 (continued). Urine concentrations of selected phthalate metabolites in the U.S. population
age 6 years and older, 1999-2002"
Geometric mean and selected percentiles of
phthalate metabolite concentrations5 cd
Survey years Sample size Geometric mean 50ln
75*
90th
95th
Mono-2-ethylhexyl phthalate
ug/L of urine
ug/g of creatinine
Mono-n-octyl phthalate
|ig/L of urine
|ig/g of creatinine
Mono-isononyl phthalate
|ig/L of urine
|ig/g of creatinine
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
1999-2000
2001-2002
2,541
2,782
2,541
2,772
2,541
2,782
2,541
2,772
2,541
2,782
2,541
2,772
3.4
4.3
3.1
4.0
NC
NC
NC
NC
NC
NC
NC
NC
3.2
4.1
3.1
3.9
-------
1 • Generally recognized reference levels for phthalate metabolites in urine have not been
2 established.
3 Data Sources
4 Data used for this indicator were extracted from the CDC report that presents results of the ongoing
5 National Health and Nutrition Examination Survey (CDC, 2005). The underlying laboratory data
6 supporting CDC's report are available online in SAS® transport file format at
7 http: //www .cdc. gov/nchs/about/maj or/nhanes/datalink .htm.
8 References
9 Barr, D.B., L.C. Wilder, S.P. Caudill, A.J. Gonzalez, L.L. Needham, and J.L. Pirkle. 2004. Urinary
10 creatinine concentrations in the U.S. population: implications for urinary biological monitoring
11 measurements. Environ. Health Persp. 113:192-200. Accessed September 14, 2005.
12
13 CDC (Centers for Disease Control and Prevention). 2005. Third national report on human exposure to
14 environmental chemicals. NCEH publication no. 05-0570. Accessed September 29, 2005.
15
16 CDC (Centers for Disease Control and Prevention). 2004. NHANES analytic guidelines. June 2004
17 version. Accessed October 21, 2005.
18
19 CDC (Centers for Disease Control and Prevention). 2002. NHANES 1999-2000 addendum to the
20 NHANES III analytic guidelines. Updated August 30, 2002. Accessed October 11, 2005.
21
22 U.S. EPA. 2005. Consumer factsheet on: di(2-ethylhexyl)phthalate. Accessed March 21, 2005.
23
24 Kavlock, R., et al. 2002a. NTP Center for the evaluation of risks to human reproduction: phthalates expert
25 panel report on the reproductive and developmental toxicity of di-n-octyl phthalate. Reprod. Toxicol.
26 16(5):721-734.
27 Kavlock, R., et al. 2002b. NTP Center for the evaluation of risks to human reproduction: phthalates expert
28 panel report on the reproductive and developmental toxicity of di-n-hexyl phthalate. Reprod. Toxicol.
29 16(5):709-719.
30 Kavlock, R., et al. 2002c. NTP Center for the evaluation of risks to human reproduction: phthalates expert
31 panel report on the reproductive and developmental toxicity of di-isononyl phthalate. Reprod. Toxicol.
32 16(5):679-708.
33 Kavlock, R., et al. 2002d. NTP Center for the evaluation of risks to human reproduction: phthalates expert
34 panel report on the reproductive and developmental toxicity of di-isodecyl phthalate. Reprod. Toxicol.
35 16(5):655-678.
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1 Kavlock, R., et al. 2002e. NTP Center for the evaluation of risks to human reproduction: phthalates expert
2 panel report on the reproductive and developmental toxicity of di(2-ethylhexyl)phthalate. Reprod.
3 Toxicol. 16(5):529-653.
4 Kavlock, R., et al. 2002f. NTP Center for the evaluation of risks to human reproduction: phthalates expert
5 panel report on the reproductive and developmental toxicity of di-n-butyl phthalate. Reprod. Toxicol.
6 16(5):489-527.
7 Kavlock, R., et al. 2002g. NTP Center for the evaluation of risks to human reproduction: phthalates expert
8 panel report on the reproductive and developmental toxicity of butyl benzyl phthalate. Reprod. Toxicol.
9 16(5):453-487.
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1 5.4.3 Discussion
2 What These Indicators Say About Trends in Exposure to Environmental
3 Contaminants
4 The biomonitoring indicators presented in this section provide an overall representation of the levels of
5 selected contaminants, or metabolites of contaminants, in human blood and urine across the U.S.
6 population. Measurable levels of many of these contaminants appear in at least some subset of the
7 populations tested. Together, these indicators help us understand the extent to which exposure to
8 individual substances has or has not occurred on a national scale.
9 Lead, mercury, cadmium, POP metabolites, and cotinine were reported at varying levels in sampled blood
10 and the metabolites of pesticides and phthalates in the urine of a subset of those tested. Based on the
11 available data, some notable changes in blood levels were reported over time, primarily for the metals.
12 Compared to historic data collected by CDC, blood lead levels have been steadily declining since the
13 1980s. The same general observation is true for blood cotinine (see Section 2.4).
14 Most blood mercury levels in children and women tested were reported below 5.8 (ig/L—levels believed
15 not to be associated with harmful health effects. However, nearly 6 percent of women tested showed
16 blood mercury between 5.8 and 58 (ig/L. The latter level is considered a general lower bound for
17 neurological effects in developing fetuses and children of exposed mothers.52
18 Current NHANES datasets provide some information about variability of biomarkers across age, gender,
19 race, or ethnicity. Such analysis is only possible, however, for those chemicals frequently measured above
20 the level of detection. For example, blood lead levels are highest among children; cadmium levels are
21 reported highest in the most recent survey in those 20 years and older. Blood mercury levels are reported
22 for children age 1-5 years and women of child-bearing age only, with the highest levels reported in the
23 latter group. In most cases where disparities are observed, it is unknown whether the differences observed
24 represent differences in exposure, pharmacokinetics (absorption, distribution, metabolism, and excretion),
25 or the relationship of dose per body weight.53
26 Limitations, Gaps, and Challenges
27 Available national level data provide information on the general magnitude of exposures that are
28 occurring for this subset of contaminants. Further, they serve as a firm foundation or baseline for future
29 analysis. However, available indicator data answer only a part of the question. At this point in time, most
30 of the biomonitoring indicators alone do not 1) enable an extensive assessment of temporal trends, 2)
31 identify and explain possible differences among some subpopulations, 3) provide information on the
32 geographic distribution of the population of concern, or any particular "hot spots" that may exist, 4)
33 reveal exposure conditions, 5) provide information for all contaminants of potential interest, 6) consider
34 exposure to multiple contaminants, or 7) provide perspective as to whether measured levels are elevated
52 Centers for Disease Control and Prevention. 2005. Third national report on human exposure to environmental
chemicals. NCEH publication no. 05-0570.
53 Centers for Disease Control and Prevention. 2005. Third national report on human exposure to environmental
chemicals. NCEH publication no. 05-0570.
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1 or likely to cause harmful effects. These represent the most notable limitations, challenges, and data gaps
2 of EPA interest in answering the question of trends in exposure to environmental contaminants.
3 Temporal Trends. The relatively short time frame of the indicator dataset limits the analysis of temporal
4 trends, but these indicators can serve as a baseline for future analysis. Most of the indicators presented to
5 answer this question reflect data from only one or two NHANES sampling periods (1999-2000 and 2001-
6 2002). Only as additional NHANES reports are released every two years, will meaningful temporal trend
7 analysis be possible. However, CDC has been monitoring blood lead and cotinine since approximately
8 1976; for these contaminants, more meaningful temporal trend analysis is possible.
9 Subgroup Analysis. The adequacy of data for subgroup evaluations varies by indicator. The NHANES
10 datasets presented in this chapter contain a sufficiently large sample size to provide reliable age, gender,
11 race, and ethnicity subgroup analyses. In some cases, however, the numbers of observations were
12 insufficient to meet statistical reliability or confidentiality requirements for reporting estimates for all race
13 or ethnicity categories.54 The benefits of such analyses have been demonstrated in earlier NHANES
14 subgroup comparisons of blood lead levels (e.g., children age 1-5 years, children living in urban or low-
15 income areas), which have allowed resources to be targeted to higher risk or susceptible populations.
16 However, not all ages are represented for all biomarkers in NHANES. Further, in cases where a small
17 percentage of samples had detectable concentrations of the measured contaminant, subgroup comparisons
18 are not possible or less meaningful.
19 Geographic Trends. The data currently available do not allow for reliable regional subgroup analyses,
20 because the number of geographic regions sampled each year is relatively small. Although the NHANES
21 sampling scheme is designed to obtain a cross-section of data from various regions across the United
22 States, the dataset is not sufficiently representative to allow inferences about regional levels of the
23 selected biomonitoring indicators.
24 Exposure Conditions. Biomonitoring data alone do not provide information on when or how exposure to a
25 particular contaminant occurred. Many different exposure scenarios (e.g., acute high exposure versus
26 long-term low-level exposures) can lead to the same concentration measured in the body. The measure
27 does not necessarily identify the source(s) of that contaminant or how a person was exposed (e.g.,
28 exposure via drinking water versus food versus inhalation; environmental versus non-environmental
29 source). Biomarkers of exposure integrate exposures across multiple exposure routes. Additional
30 information on ambient conditions would be needed to determine what exposures contribute to
31 concentrations in people's bodies. For example, lead in children's blood may come from exposure to
32 airborne sources, contaminated water or food, or contaminated soil or dust. In addition, some biomarkers
33 are not specific to a particular contaminant, making interpretation of the data and its significance
34 uncertain. Lastly, some environmental contaminants are also produced in trace amounts by normal
35 metabolic processes (e.g., formaldehyde and acetone), so their presence cannot always be attributed to
36 external exposure.55'56
54 National Center for Health Statistics. 2005. Health, United States, 2005, with chartbook on trends in the health of
Americans. DHHS publication no. 2005-1232. Hyattsville, MD
55 Watson, W.P., and A. Mutti. 2004. Role of biomarkers in monitoring exposures to chemicals: present position,
future prospects. Biomarkers 9(3):211-242.
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1 Other Environmental Contaminants. There are still many contaminants for which no biomonitoring
2 indicators exist, and others that are simply not feasible to analyze using current technology or data
3 collection methods. For example, although it is possible to measure the amount of radiation that a person
4 is exposed to using a dosimeter, biomarkers are not yet feasible for national estimates of exposure to
5 radon. Similar issues of feasibility exist with other contaminants, including most criteria air pollutants
6 (e.g., ozone, nitrogen dioxide, carbon monoxide, and particulate matter), biological agents (e.g., molds,
7 certain infectious agents such as bacteria or viruses, or dust mites), byproducts from the disinfection of
8 drinking water (e.g., chlorine or chlorine-containing compounds), and several contaminants commonly
9 found in air and drinking water at Superfund sites (e.g., trichloroethylene and tetrachloroethylene, among
10 others). In many cases, biomonitoring for these contaminants is either cost-prohibitive or not yet
11 technologically feasible. However, biomonitoring methods are constantly evolving. For example, CDC
12 has added a number of environmental contaminants to its biomonitoring efforts, which will be included in
13 future reports. These include arsenic, polybrominated compounds, perfluorinated compounds (e.g.,
14 perfluorooctane sulfonate [PFOS] and perfluorooctanoic acid [PFOA]), among others.57
15 In addition, there is continued concern that certain chemicals, referred to as endocrine disrupters, may
16 contribute to adverse health effects in humans and may impact the health of future generations.
17 Information about the magnitude and pattern of human exposure to endocrine disrupters is being collected
18 for only a small subset of chemicals that comprise this group (e.g., PCBs, DDT and its metabolites);
19 wider testing will be challenging because there are still many compounds that have not yet been classified
20 as endocrine disrupters, but may someday be identified as such. Moreover, understanding the specific
21 window of vulnerability during different stages of development will be critical in evaluating the potential
22 harmful effects of these chemicals.
23 Multiple contaminants. Current biomonitoring indicators do not consider the effects of exposures to
24 multiple contaminants. Specifically, biomarker measurements that are collected in NHANES do not
25 provide any perspective regarding how different classes of contaminants interact with one another once
26 they enter the body and to what extent these chemicals are additive, antagonistic, or synergistic.
27 Clinical Reference or Comparison Levels. For most available biomonitoring indicators, no general
28 scientific consensus exists as to how to interpret measured levels of contaminants in blood and urine. For
29 example, are measured levels associated with some clinical effect or elevated above some "safe" or
30 "background" level? Tracking trends in exposure over time, combined with trends in ambient
31 measurements and health outcome measurements, is a key part of establishing such reference values.
32 Establishing background or reference ranges (distributions) will help in identifying people with unusually
33 high exposure or the percentage of the populations with contaminant exposures above established levels
34 of concern.
56 Bates, M.N., J.W. Hamilton, IS. LaKind, P. Langenberg, M. O'Malley, and W. Snodgrass. 2005. Workgroup
report: biomonitoring study design, interpretation, and communication—lessons learned and path forward. Environ.
Health Perspect. 113(11):1615-1621.
57 Department of Health and Human Services. 2003. Candidate chemicals for possible inclusion in future releases of
the national report on human exposure to environmental chemicals. Federal Register 68(189): 56296-98. September
30.
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CHAPTER 6
ECOLOGICAL CONDITION
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ECOLOGICAL CONDITION CHAPTER CONTENTS
6.1 INTRODUCTION 6-5
6.1.1 The Ecological Condition Paradigm 6-6
6.1.2 Overview of the Data 6-7
6.1.3 Organization of This Chapter 6-8
6.2 WHAT ARE THE TRENDS IN THE EXTENT AND DISTRIBUTION OF THE
NATION'S ECOLOGICAL SYSTEMS? 6-11
6.2.1 Introduction 6-11
6.2.2 ROE Indicators 6-13
INDICATOR: Forest Extent and Type 6-14
INDICATOR: Forest Fragmentation 6-17
INDICATOR: Ecological Connectivity in EPA Region 4 6-20
INDICATOR: Relative Ecological Condition of Undeveloped Land in EPA
Region 5 6-22
6.2.3 Discussion 6-25
What These Indicators Say about Trends in Extent and Distribution of the Nation's
Ecological Systems 6-25
Limitations, Gaps, and Challenges 6-27
6.3 WHAT ARE THE TRENDS IN THE DIVERSITY AND BIOLOGICAL BALANCE OF
THE NATION'S ECOLOGICAL SYSTEMS? 6-29
6.3.1 Introduction 6-29
6.3.2 ROE Indicators 6-30
INDICATOR: Bird Populations 6-32
INDICATOR: Fish Faunal Intactness 6-34
INDICATOR: Non-Indigenous Species in the Estuaries of the Pacific Northwest 6-37
6.3.3 Discussion 6-40
What These Indicators Say About Trends in the Diversity and Biological Balance of
the Nation's Ecological Systems 6-40
Limitations, Gaps, and Challenges 6-41
6.4 WHAT ARE THE TRENDS IN THE ECOLOGICAL PROCESSES THAT SUSTAIN THE
NATION'S ECOLOGICAL SYSTEMS? 6-43
6.4.1 Introduction 6-43
6.4.2 ROE Indicators 6-44
INDICATOR: Carbon Storage in Forests 6-45
6.4.3 Discussion 6-48
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What This Indicator Says About Trends in the Ecological Processes that Sustain the
Nation's Ecological Systems 6-48
Limitations, Gaps, and Challenges 6-48
6.5 WHAT ARE THE TRENDS IN THE CRITICAL PHYSICAL AND CHEMICAL
ATTRIBUTES AND PROCESSES OF THE NATION'S ECOLOGICAL SYSTEMS? 6-50
6.5.1 Introduction 6-50
6.5.2 ROE Indicators 6-51
INDICATOR: U.S. and Global Mean Temperature and Precipitation 6-53
INDICATOR: Sea Surface Temperature 6-58
INDICATOR: Sea Level 6-61
6.5.3 Discussion 6-67
What These Indicators Say About Trends in Critical Physical and Chemical
Attributes of the Nation's Ecological Systems 6-67
Limitations, Gaps, and Challenges 6-70
6.6 WHAT ARE THE TRENDS IN BIOMARKERS OF EXPOSURE TO COMMON
ENVIRONMENTAL POLLUTANTS IN PLANTS AND ANIMALS? 6-72
6.6.1 Introduction 6-72
6.6.2 ROE Indicators 6-72
6.6.3 Discussion 6-73
What These Indicators Say About Trends in Biomarkers of Exposure to Common
Environmental Pollutants in Plants and Animals 6-73
Limitations, Gaps, and Challenges 6-74
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1 6.1 INTRODUCTION
2 Ecological condition refers to the state of the physical, chemical, and biological characteristics of the
3 environment, and the processes and interactions that connect them. Understanding ecological condition is
4 crucial, because humans depend on healthy ecological systems for food, fiber, flood control, and other
5 benefits,1 and many Americans attribute deep significance and important intangible benefits to ecological
6 systems and their diverse flora and fauna.2 As noted in the introduction to this report, this chapter focuses
7 on critical characteristics of ecosystems that are affected simultaneously by stressors in multiple media,
8 rather than those whose trends can be definitively shown to be the results of trends in particular air, water,
9 or land stressors. The ability to report on ecological condition remains significantly limited by the lack of
10 indicators, but this chapter at least provides a framework for examining those conditions.
11 EPA's mission, broadly stated, is "to protect human health and to safeguard the natural environment-air,
12 water, and land-upon which life depends."3 The translation of the mission into programs, initiatives, and
13 research efforts continues to evolve within the Agency and is reflected in program goals, regulatory
14 programs, and collaborative and educational efforts. EPA, other federal agencies, and state agencies
15 collectively bear responsibility for ensuring the protection of ecological systems, including forests, public
16 lands, oceans and estuaries, and particular species or groups of species. Trends in ecological conditions
17 provide insight into the degree to which the natural environment is being protected.
18 In this chapter, EPA seeks to assess trends in critical attributes of ecological condition on a national scale
19 using indicators to address five fundamental questions:
20 • What are the trends in the extent and distribution of the nation's ecological systems? This
21 section examines trends in the overall extent (e.g., area and location) of different kinds of
22 ecological systems (e.g. forests, undeveloped lands, and watersheds) and of spatial patterns in
23 the distribution of ecological systems that affect interactions of nutrients, energy, and
24 organisms.
25 • What are the trends in the diversity and biological balance of the nation's ecological
26 systems? This section explores trends in the types and numbers of species that live within
27 ecological systems. The section also examines biological balance in terms of the proportional
28 distributions of species and the influence of interactions among native and invasive species
29 on the stability of ecological systems.
30 • What are the trends in the ecological processes that sustain the nation's ecological
31 systems? This question focuses on trends in the critical processes that sustain ecological
32 systems, such as primary and secondary productivity, nutrient cycling, decomposition, and
33 reproduction.
34 • What are the trends in the critical physical and chemical attributes and processes of the
35 nation's ecological systems? This question addresses trends in physical attributes such as
1 Daily, G.C, ed. 1997. Nature's services: societal dependence on natural ecosystems. Washington, DC: Island Press.
2 Norton, B. 1988. Commodity, amenity, and morality: the limits of quantification in valuing biodiversity. In:
Wilson, E.O., ed. Biodiversity. Washington, DC: National Academy Press, p. 521.
3 U.S. EPA. About EPA.
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1 climatological patterns, hydrology, and light. This section also examines how chemical
2 processes influence conditions such as pH, oxidation-reduction potential, and nutrient cycles.
3 • What are the trends in biomarkers of exposure to common environmental pollutants in
4 plants and animals? This question examines trends in biomarkers of exposure to pollutants
5 that are particularly important to the health of plants and animals as well as to humans who
6 consume such organisms.
7 These ROE questions are posed without regard to whether indicators are available to answer them. This
8 chapter presents the indicators available to answer these questions, and also points out important gaps
9 where nationally representative data are lacking.
10 While the ecological (and, in the previous chapter, human health) indicators may be more or less directly
11 influenced by pollutants, other environmental stressors, and complex interactions among these factors, the
12 indicators are not intended to confirm direct causal relationships.
13 6.1.1 The Ecological Condition Paradigm
14 Because ecological systems are dynamic assemblages of organisms that have more or less continuously
15 adapted to a variety of natural stresses over shorter (e.g., fire, windstorms) and longer (climate variations)
16 periods of time, measuring ecological condition is a complicated endeavor. It is not as straightforward as
17 monitoring water or air for temperature or concentrations of pollutants. The complexity of interactions
18 comprising ecological systems makes determination of the condition of a natural system difficult.4 In
19 addition, people have altered natural ecological systems to increase the productivity of food, timber, fish,
20 and game and to provide the infrastructure needed to support a modern society. How should the
21 ecological condition of these altered ecological systems be measured and against what reference points?
22 Ecological systems are not necessarily naturally occurring entities with well-defined, mutually exclusive
23 boundaries; rather, they are constructs with boundaries determined for human scientific or management
24 purposes. Consequently there are many ways to define ecological systems, including by the predominant
25 biota, spatial scales, and physical characteristics. These factors further complicate the definition and
26 measurement of ecological condition. Several recent reports by experts in the field have provided
27 guidance for current and future efforts, however.
28 The National Research Council (NRC) report Ecological Indicators for the Nation5 provides an
29 introduction to recent national efforts to measure ecological condition and a thoughtful discussion of the
30 rationale for choosing indicators. EPA's Science Advisory Board (SAB) also proposed a Framework for
31 Assessing and Reporting on Ecological Condition.6 The framework identified six essential ecological
32 attributes of ecological systems: landscape condition, biotic condition, chemical and physical
33 characteristics, ecological processes, hydrology and geomorphology, and natural disturbance regimes.
4 Ehrenfeld, D.H. 1992. Ecosystem health and ecological theories. In: Costanza, R., et al, eds. Ecosystem health:
new goals for environmental management. Washington, DC: Island Press, pp. 135-143.
5 National Research Council. 2000. Ecological indicator for the nation. Washington, DC: National Academies Press.
6 U.S. EPA. 2002. A framework for assessing and reporting on ecological condition: an SAB report.
EPA/SAB/EPEC-02/009.
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1
2
3
4
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6
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9
10
11
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13
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23
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31
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The SAB report is organized around questions
about trends in each of these attributes,
consolidating the last three into a single attribute.
Neither report identifies specific methodologies,
network designs, or actual datasets. The SAB and
NRC documents provide the foundation for the
questions that are addressed within this chapter.
Exhibit 6-1 is a conceptual depiction of the events
that link environmental changes and ecological
outcomes in this paradigm. "Stressors," indicated
by arrows, represent factors such as insect
outbreaks or
pollutants affecting the system. These act directly
on one or more of the "essential ecological
attributes" shown in the circles in the center of the
diagram. Most of these attributes can, in turn, act
on and be acted on by others. The web of arrows
among the indicators illustrates some of the
possible interactions. Effects on ecological
attributes can be direct or indirect. The diagram
illustrates the fact that changes in ecological
structure and processes provide important
feedback on the chemical and physical structure
of the environment in which these changes occur. The
structure and function of ecological systems, which in
which society is concerned.
Exhibit 6-1. Ecological condition paradigm
Stressors (shown as ) affect ecological attributes directly and
also indirectly through feedback (interaction) among the
attributes (f).
overall changes in the attributes result in altered
turn lead to outcomes (positive or negative) about
There have been other notable efforts conducted by EPA and other federal agencies and institutions to
describe the ecological condition of the nation, either in total or by type of ecological systems. These
efforts include both indicator-based and integrative approaches. The indicator-based approaches, such as
this report, use indicators to assess ecological condition. The integrated assessments do not rely on
indicators; rather, they comprehensively assess a wide range of data in order to arrive at an overall picture
of the status and trends in ecological systems. Indicator approaches offer the advantage of drawing
attention to important trends and don't require an extensive background in ecology, but are not able to
capture the complex interactions that characterize ecological systems.
6.1.2 Overview of the Data
This chapter, like the others in this report, is not intended to be exhaustive. Rather, it provides a snapshot,
at the national level, of current indicators of U.S. ecological condition and the status based on important
endpoints and data sources with study design, quality assurance, and maturity. Because ecological
condition depends critically on the physical and chemical characteristics of land, air, and water, this
chapter draws on indicators from Chapters 2 through 4 of this report. Those chapters should be consulted
for the data sources of those indicators. Many of the indicators continue to be drawn from The H. John
Heinz III Center for Science, Economics, and the Environment (The Heinz Center) report, The State of
the Nation's Ecosystems: Measuring Lands, Waters, and Living Resources of the United States (2002;
Web update 2005).
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1 Most of the data relied upon come from surveillance and monitoring surveys. The key data sources for
2 this chapter reflect the fact that monitoring ecological condition is a multi-organizational task.
3 Organizations in addition to EPA that are responsible for collecting the data to support indicators in this
4 chapter include the U.S. Department of Commerce (National Oceanic and Atmospheric Administration),
5 National Aeronautics and Space Administration, U.S. Department of Agriculture (Forest Service,
6 Agricultural Research Service, National Agricultural Statistics Service, and Natural Resource
7 Conservation Service), U.S. Department of Interior (U.S. Geological Survey and U.S. Fish and Wildlife
8 Service), and NatureServe (a private foundation).
9 Programs such as the U.S. Department of Agriculture Forest Inventory and Analysis (FIA) program and
10 the Natural Resources Inventory (NRI) have a long history because they measure aspects of the
11 environment that are critical to multi-billion dollar industries (e.g., timber, crops, etc.). Programs with a
12 strictly "ecological" focus (e.g., the USDA Forest Service Forest Health Monitoring [FHM] Program, the
13 U.S. Geological Survey National Water Quality Assessment Program [NAWQA], the multi-agency
14 Multi-Resolution Land Characterization Consortium [MRLC], and EPA's Environmental Monitoring and
15 Assessment Program [EMAP]) are more recent, but equally informative.
16 The major challenges involve adequate coverage of the diverse aspects that comprise ecological
17 condition. For example, there are numerous groups of animals and plants, but there are ROE indicators
18 for only some of these. Major groups known to be undergoing changes, such as the amphibians, are not
19 captured by the ROE indicators. These challenges and limitations are described in each of the subsections.
20 This chapter presents only data that meet the ROE indicator definition and criteria (see Chapter 1,
21 Introduction). Note that non-scientific indicators, such as administrative and economic indicators, are not
22 included in this definition. Thorough documentation of the indicator data sources and metadata can be
23 found online at [insert url]. All indicators were peer-reviewed during an independent peer review process
24 (see [insert url] for more information. Readers should not infer that the indicators included reflect the
25 complete state of knowledge on current indicators of U.S. ecological condition. Many other data sources,
26 publications, and site-specific research projects have contributed to the current understanding of status
27 and trends in indicators of U.S. ecological condition, but are not used in this report because they do not
28 meet some aspect of the ROE indicator criteria.
29 6.1.3 Organization of This Chapter
30 The remainder of this chapter is organized into five sections, corresponding to the five questions EPA is
31 seeking to answer regarding trends in ecological condition. Each section introduces the question and its
32 importance, presents the National Indicators selected to help answer the question, and discusses what the
33 indicators, taken together, say about the question. Some of the National Indicators presented are broken
34 down by EPA Regions or other appropriate regions. In addition, several Regional Indicators are presented
35 that capture regional trends of particular interest to EPA Regions. These Regional Indicators serve as
36 models that could potentially be expanded to other EPA Regions in the future. A map showing the EPA
37 regions (and states within each region) is provided in Chapter 1 (Exhibit l-l).Each section concludes by
38 highlighting the major challenges to answering the question and identifying important gaps and emerging
39 issues.
40 The table below shows the indicators used to answer each question and the location where they are
41 presented.
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1 Table 6.1.1. Ecological Condition—ROE Questions and Indicators
Question
What are the trends in the extent
and distribution of the nation 's
ecological systems?
Indicator Name
Land Cover (N/R)
Forest Extent and Type (N/R)
Forest Fragmentation (N/R)
Wetland Extent, Change and Sources of Change
(N)
Land Use (N)
Urbanization and Population Change (N)
Land Cover in the Puget Sound/Georgia Basin
(R)
Ecological Connectivity in EPA Region 4 (R)
Relative Ecological Condition of Undeveloped
Land in EPA Region 5 (R)
Section Page #
4.2.2 4-11
6.2.2 6-14
6.2.2 6-17
3.4.2 3-53
4.3.2 4-24
4.3.2 4-31
4.2.2 4-17
6.2.2 6-20
6.2.2 6-22
What are the trends in the
diversity and biological balance of
the nation 's ecological systems?
Coastal Benthic Communities (N/R)
Benthic Macroinvertebrates in Wadeable
Streams (N)
Bird Populations (N)
Fish Faunal Intactness (N)
Submerged Aquatic Vegetation in the
Chesapeake Bay (R)
Harmful Algal Bloom Outbreaks Along the
Western Florida Coastline (R)
Non-Indigenous Species in the Estuaries of the
Pacific Northwest (R)
3.5.2 3-71
3.2.2 3-35
6.3.2 6-32
6.3.2 6-34
3.5.2 3-74
3.5.2 3-81
6.3.2 6-37
What are the trends in the
ecological processes that sustain
the nation 's ecological systems?
What are the trends in the critical
physical and chemical attributes
of the nation 's ecological systems?
Carbon Storage in Forests (N)
U.S. and Global Mean Temperature and
Precipitation (N)
Sea Surface Temperature (N)
High and Low Stream Flows (N)
Streambed Stability in Wadeable Streams (N)
Sea Level (N)
Nitrogen and Phosphorus Discharge from Large
Rivers (N)
Nitrogen and Phosphorus in Wadeable Streams
(N)
Nitrogen and Phosphorus in Streams in
Agricultural Watersheds (N)
Lake and Stream Acidity (N)
Extent of Hypoxia in the Northern Gulf of
Mexico and in Long Island Sound (R)
6.4.2 6-45
6.5.2 6-53
6.5.2 6-58
3.2.2 3-14
3.2.2 3-19
6.5.2 6-61
3.2.2 3-28
3.2.2 3-22
3.2.2 3-25
2.2.2 2-62
3.5.2 3-77
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Question
What are the trends in biomarkers
of exposure to common
environmental pollutants in plants
and animals?
Indicator Name
Coastal Fish Tissue Contaminants (N/R)
Ozone Injury to Forest Plants (N)
Contaminants in Lake Fish Tissue (N)
Section Page #
3.8.2 3-103
2.2.2 2-37
3.8.2 3-107
1
2
3
4
N = National Indicator
R = Regional Indicator
N/R = National Indicator displayed at EPA Regional scale
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1 6.2 WHAT ARE THE TRENDS IN THE EXTENT AND DISTRIBUTION OF THE
2 NATION'S ECOLOGICAL SYSTEMS?
3 6.2.1 Introduction
4 Ecological systems,7 ranging from forests and watersheds to wetlands and coral reefs, are the foundation
5 of the environment. An ecological system can be defined as a spatially explicit unit of the Earth that
6 includes all of the organisms, along with all components of the abiotic environment, within its
7 boundaries. Ecological systems are not isolated but blend into and interact with other systems. The spatial
8 coverage and arrangement of ecological systems influence the types of animals and plants that are
9 present; the physical, chemical, and biological processes in the system; and the resiliency of the systems
10 to perturbations.8 Ecological systems influence water and nutrient cycles, the building of soils, the
11 production of oxygen, sequestration of carbon, and many other functions important for the health of the
12 planet and the people who depend on them.
13 This section examines trends in the extent and distribution of ecological systems. Extent refers to the
14 physical coverage of an ecological system. This may be reflected as area or percent compared to a
15 baseline or total area. Distribution includes the pattern or arrangement of the components of an ecological
16 system and is dependent on the scale of analysis. For example, the national distribution of forests can be
17 estimated by a percent coverage, but within a stand of trees the distribution may involve patterns of gaps,
18 species, and edge/interior ratios. As noted in Section 6.1.1, ecological systems can be defined by
19 predominant biota, spatial scales, and physical characteristics. Extent indicators typically are based on
20 physical and biological characteristics that are observable by remote sensing, with indistinct boundaries
21 operationally defined according to some scientific or resource management construct.9
22 As noted in Chapter 1 (Introduction), safeguarding the natural environment is an integral part of the
23 EPA's mission. EPA traditionally has been most concerned with maintaining the quality of air, water, and
24 land necessary to support balanced biological communities and the processes that support them; however,
25 the success of these efforts requires that ecological systems not be altogether lost or fragmented. The
26 potential influences of pollutants on the extent and distribution of ecological systems are a prime concern,
27 and, in turn, the extent and distribution of ecological systems has far-reaching influences on air and water
28 quality.
29 Apparent trends in extent and distribution of ecological systems depend on the temporal and spatial scale
30 of assessment. For this reason, National and Regional Indicators are particularly valuable. Temporal
31 changes occur naturally over long time scales, such as those associated with geological and climatological
32 forces (e.g., glaciation). Change can also occur more quickly as a result of direct shifts in land use (e.g.,
33 forest to development and historical filling of wetlands), alterations of nutrient and hydrological cycles
7 Likens, G. 1992. An ecosystem approach: its use and abuse. Excellence in ecology, book 3. Oldendorf/Luhe,
Hermany: Ecology Institute.
8 Wilson, E.G. 1992. The diversity of life. Cambridge, MA: Belknap Press, 1992.
9 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. The state of the nation's
ecosystems: measuring the lands, waters, and living resources of the United States. New York, NY: Cambridge
University Press, September 2002. Web update 2005.
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1 (e.g., dam removal), introduction of invasive species (e.g., Asian carp), hazardous waste exposure (e.g.,
2 acid rain), or extreme weather events, which all act over comparatively short time periods. Thus, trends
3 can be the result of natural forces or may be accelerated by human activity.
4 The spatial scale of alterations also represents a significant factor in tracking ecological condition.
5 Alterations that are short in duration and local in nature (e.g., seasonal droughts or a windfall in a closed
6 forest canopy) may not have large-scale or lasting effects on ecological systems. Alterations that are
7 chronic in nature and occur over large areas may affect entire ecosystems over long periods of time,
8 especially if they affect soil formation, microclimate, refugia for recolonizing species, etc. Particularly
9 relevant discussions of the importance of scale in ecological processes, monitoring, and management can
10 be found in a number of relatively recent publications.10'11'12
11 Different regions and different ecological systems respond to stressors in different ways, resulting in
12 unique regional distributions of species and habitats. The result is that across any slice of landscape the
13 extent and distribution of ecological systems may shift.13 In the case of habitat loss, large impacts may
14 occur and the extent of coverage may be reduced or eliminated altogether. More subtle changes in
15 ecological systems can occur which are not captured in simple metrics of extent and distribution. These
16 are discussed in later sections of this chapter.
17 Fragmentation, the division of previously uninterrupted habitat, can have either negative or positive
18 impacts on communities.14 Examples of fragmentation include building highways through a forest,
19 damming a river in a manner that limits migration of fish, or developing waterfronts in a manner that
20 splits apart bordering marshlands. Fragmentation and the increasing area of edge habitat may force
21 migrating species to find new transport corridors, may allow new species (e.g., competitors, pathogens,
22 weeds) to enter areas previously blocked from immigration, and in some cases may actually increase
23 biodiversity.15 Regardless of the impact, fragmentation likely will result in shifting distributions of
24 species.
10 Peterson, D.L., and V. Thomas Parker. 1998. Ecological scale: theory and applications. New York: Columbia
University Press. 615 pp.
11 Niemi, G., and M. McDonald. 2004. Application of ecological indicators. Annu. Rev. Ecol. Evol. Syst. 35:89-
111.
12 Findlay, C.S., and L. Zheng. 1997. Determining characteristic stressor scales for ecosystem monitoring and
assessment. J. Environ. Manage. 50(3):265-281.
13 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. Forest pattern and
fragmentation. In: The state of the nation's ecosystems: measuring the lands, waters, and living resources of the
United States. New York, NY: Cambridge University Press, September 2002. Web update 2005.
14 Fahrig, L. 1997. Relative effects of habitat loss and fragmentation on population extinction. J. Wildl. Manage.
61(3):603-610.
15 Fahrig, L. 2003. Effects of habitat fragmentation on biodiversity. Annu. Rev. Ecol. Syst. 34:487-515.
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1 Trends in ecological system extent and distribution are highly dependent on the evaluation scale. At one
2 scale, coastal wetlands may appear to be uninterrupted and uniform. However, at a more refined scale,
3 edges, patches, corridors associated with tidal creeks, and discontinuous distributions of species become
4 evident. Defining systems in terms of local organization or predominant species facilitates discussion and
5 analysis, but may also obscure the important linkages among systems across landscapes. Therefore, while
6 it is helpful to discuss trends in the extent and distribution of systems such as wetlands or forests, each
7 system is tied into global water, nutrient, carbon, and energy cycles.
8 The indicators discussed in this section fall into three broad categories: indicators of the extent and
9 distribution of forests, indicators of the extent and distribution of wetlands, and indicators of land use.
10 6.2.2 ROE Indicators
11 In this question, trends in the extent and distribution of ecological systems are evaluated for a subset of
12 systems including forests, wetlands, undeveloped lands, and developed lands.
13 To answer the question on extent and distribution of ecological systems, this report relies primarily on six
14 National Indicators and three Regional Indicators (Table 6.2.1). Data on trends in extent and distribution
15 of ecological systems come from a variety of sources, including satellite remote sensing, geographic
16 information systems, and independent field studies. Information for the indicators discussed in this
17 section is drawn from several national assessments including the USDA Forest Service Forest Inventory
18 Analysis System, the National Wetlands Inventory Status and Trends Survey, the National Level Cover
19 Data Set (NLDC) for 1992, and the USDA National Resources Inventory.
20 Table 6.2.1. ROE Indicators of Trends in Extent and Distribution of the Nation's Ecological
21 Systems
NATIONAL INDICATORS
Land Cover (N/R)
Forest Extent and Type (N/R)
Forest Fragmentation (N/R)
Wetland Extent, Change and Sources of Change
Land Use
Urbanization and Population Change
REGIONAL INDICATORS
Land Cover in the Puget Sound/Georgia Basin
Ecological Connectivity in EPA Region 4
Relative Ecological Condition of Undeveloped Land in EPA Region 5
LOCATION
4.2.2 -p. 4-11
6.2.2 -p. 6-14
6.2.2 -p. 6-17
3.4.2 -p. 3-53
4.3.2 -p. 4-24
4.3.2 -p. 4-31
4.2.2 -p. 4-17
6.2.2 -p. 6-20
6.2.2 -p. 6-22
22 N/R = National Indicator displayed at EPA Regional scale
23
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NDICATOR: Forest Extent and Ty.
19
20
21
22
23
24
25
2 The forests of the U.S. cover extensive lands in both the eastern and western thirds of the country. While
3 the amount of forest land has remained nearly unchanged since the beginning of the 20th century, regional
4 changes both in amount and types of forest cover have occurred as a result of changing patterns of
5 agriculture and development. The distribution of various forest cover types is a critical determinant of the
6 condition of forest ecosystems.
7 This indicator is based on data from the USDA Forest Service Forest Inventory and Analysis (FIA)
8 system. The FIA program, using a statistical survey design and comparable methods across the U.S.,
9 collects various data that help assess the extent, type, age, and health of forest land in the United States.
10 Because the surveys are repeated over time, the FIA data provide an indication of trends in both the extent
11 and composition of forest land. The extent data are collected for all forest lands across the nation, but
12 species composition data over time are only available for timber land as defined by FIA data collection
13 procedures (that is, forests capable of producing at least 20 cubic feet per acre per year of industrial wood
14 and not withdrawn from timber utilization by statute or regulation). Timberland makes up 94 percent of
15 the forest land area in the eastern U.S. and 39 percent of forest land in the western U.S. as of 2002 (Smith
16 et al., 2004). Extent data are collected for individual states, but have been summarized by EPA Region for
17 this indicator.
18 What the Data Show
After a slight increase in forest land nationwide between 1907 and 1938, forest acreage decreased by
more than 16 million acres between 1938 and 1977, before increasing by 5.3 million acres over the past
three decades (Exhibit 6-2). There are variations in trends in forest cover among the different EPA
Regions. For example, between 1907 and 2002, forest land declined by roughly 22 million acres in
Region 6 and more than 12 million acres in Region 9. Over the same period, forest land increased by 13
million acres in Region 3 and by 10 million acres in Region 5.
Exhibit 6-2. Changes in the extent of forest land in the U.S. by EPA Region, 1907-2002"
E -•
10
5
0
-5
-10
-15
15
10
5
0
-5
-10
-15
Region 1
A B C D
Region 2
A B C D
Region 3
1..
A B C D
Region 4
Jo.
• B "" D
Region 5
| B C |
A ~ ~ D
Region 7
ABC
D
Region 8
ABC
D
Region 9
A B C •
• D
Region 10
A B C D
All U.S.
3 C |
A I |D
Region f
ABC
0
Reporting
periods:
A 1907-1938
B 1938-1953
C 1953-1977
D 1977-2002
EPA Regions
© 00
o
^draRK
f^
V
Reporting period
'Coverage: All 50 states.
Data source: Smith era/., 2004
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Exhibit 6-3. Timberland area in the eastern U.S. by forest type, 1953-2002"
140
120
100
80
60
40
20
White-red-jack pine
Spruce-fir Longleaf-slash pine Loblolly-shortleaf pine Oak-pine
Oak-hickory
HUH
'53'6377'87'97'02 '53'63 77'87'97'02 '53'63'77'87'97'02 '53'63 77'87'97'02 '53'63 77'87'97'02 '53'63'77'87'97'02
120
100
40
20
0
Oak-gum-cypress
Mini
Elm-ash-cottonwood
Maple-beech-birch
mill
Aspen-birch
Mini
Non-stocked
_
'53'6377'87'97'02 '53'63 77'87'97'02 '53'6377'87'97'02 '53 TO 77'87'97'02 '53'63 77'87'97'02
Year
"Coverage: States in the eastern U.S., based on USDA Forest Service reporting regions (see map at right). These data cover timberland, as
defined by the Forest Service's Forest Inventory and Analysis (FIA) Program. Approximately 94% of the forest land in the eastern states
is timberland.
Data source: Smith etal., 2001 and 2004
Exhibit 6-4. Timberland area in the western U.S. by forest type, 1953-2002"
40
30
20
10
Douglas-fir
Ponderosa-Jeffrey Western white pine
pine
Fir-spruce
Hemlock-Sitka
spruce
Larch
Hll
153'6377'87'97'02 '53'63'77'87'97'02 '53'63 77'87'97'02 '53'6377'87'97'02 '53'63 77'87'97'02 '53'63'77'87'97'02
Lodgepole pine Redwood
Other western Western hardwood Pinyon-juniper
softwood types types
Jl
JlL,
Non-stocked
'53'6377'87'97'02 '53'63'77'87'97'02 '53'63 77'87'97'02 '53'63 77'87'97'02 '53'63 77'87'97'02 '53'63'77'87'97'02
Year
"Coverage: States in the western U.S. (including Alaska and Hawaii), based on USDA Forest Service reporting
regions (see map at right). These data cover timberland, as defined by the Forest Service's Forest Inventory
and Analysis (FIA) Program. Approximately 39% ol the forest land in the western states is timberland.
Data source: Smith etal., 2001 and 2004
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1 In addition to changes in the extent of forest, there have been changes in the types of forests over time
2 (Exhibits 6-3 and 6-4). The largest changes in the eastern U.S. over the period 1953-2002 occurred in the
3 maple-beech-birch forest type and the oak-hickory forest type, gaining 27.5 million acres and 23 million
4 acres, respectively, since 1953. In the West, the fir-spruce type and Western hardwood type also have
5 increased (about 11.5 million acres each) since 1953, while the hemlock-Sitka spruce, pinyon-juniper, and
6 ponderosa-Jeffrey pine forest types have decreased by about 13.6 million, 8.8 million, and 8.7 million
7 acres respectively. The Western white pine forest type has decreased by 5.3 million acres, or about 96
8 percent of its 1953 acreage.
9 Indicator Limitations
10 • Data on extent of forest land have an uncertainty of 3 to 10 percent per million acres for data
11 reported since 1953. In 1998 Congress mandated that the FIA move to annual inventories.
12 While data now are collected more often, fewer data are collected in any given year. Because
13 area estimates now are based on a smaller sample size, the precision of the national estimates
14 may be reduced relative to pre-1998 dates.
15 • Most of the specific data related to species and age classes are only collected on lands
16 classified as timberland and not forest land in general.
17 • In addition to extent and species class, age class also influences the use of forest land as
18 habitat by different species. Younger and older stands of forest have increased over the past
19 half-decade, while middle-aged stands of more merchantable timber have decreased (Smith et
20 al., 2001,2004).
21 Data Sources
22 This indicator is based on data from two USDA Forest Service reports (Smith et al., 2001, 2004), which
23 provide current and historical data on forest extent and type by state. Most data were obtained from the
24 2004 report; the 2001 report was consulted only for 1963 data, which were excluded from the more recent
25 report. Data were originally collected by the Forest Service's Forest Inventory and Analysis (FIA)
26 Program; original survey data are available from the FIA database (USDA Forest Service, 2005)
27 (http://www.fia.fs.fed.us/tools-data/data/).
28 References
29 Smith, W.B., P.O. Miles, J.S. Vissage, and S.A. Pugh. 2004. Forest resources of the United States, 2002.
30 General Technical Report NC-241. St. Paul, MN: USDA Forest Service, North Central Research Station.
31
32 Smith, W.B., J.S. Vissage, D.R. Darr, and RM. Sheffield. 2001. Forest resources of the United States,
33 1997. General Technical Report NC-219. St. Paul, MN: USDA Forest Service, North Central Research
34 Station,
35 USDA Forest Service. 2005. Forest Inventory and Analysis, national FIA data base systems. Accessed
36 2005.
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NDICATOR: Forest Fragmentatioi
2 The amount of forest land in the United States monitored by the USDA Forest Service has remained
3 nearly constant over the past century, but the patterns of human land-use have affected its distribution
4 from one region of the U.S. to another. Forest fragmentation involves both the extent of forest and its
5 spatial pattern, and is the degree to which forested areas are being broken into smaller patches and pierced
6 or interspersed with non-forest cover.
7 Forest fragmentation is a critical aspect of the extent and distribution of ecological systems. Many forest
8 species are adapted to either edge or interior habitats. When the degree or patterns of fragmentation
9 change, it can affect habitat quality for the majority of mammal, reptile, bird, and amphibian species
10 found in forest habitats (Fahrig, 2003). As forest fragmentation increases beyond the fragmentation
11 caused by natural disturbances, edge effects become more dominant, interior-adapted species are more
12 likely to disappear, and edge- and open-field species are likely to increase.
13 This indicator of forest fragmentation was developed by the USDA Forest Service and has appeared in
14 other recent reports (USDA Forest Service, 2004; Heinz Center, 2005). The indicator is based on the 1992
15 National Land Cover Dataset (NLCD), which was constructed from satellite imagery (Landsat) showing
16 the land area of the contiguous U.S. during different seasons (i.e., leaves-on and leaves-off) during the
17 early 1990s. In many locations, the best available Landsat images were collected between 1991 and 1993,
18 with data in a few locations ranging from 1986 to 1995. The USDA Forest Service's Southern Research
19 Station performed a re-analysis of NLCD, aggregating the four NLCD forest cover classes (coniferous,
20 deciduous, mixed, and wetland forest) into one forest class and the remaining land cover classes into two
21 classes: a non-forest class and a "missing" class consisting of water, ice/snow, and bare ground (Riitters et
22 al., 2002). Land cover in the "missing" class is not considered to fragment forest in this indicator because
23 no forest would be expected in those locations. A model that classifies forest fragmentation based on the
24 degree of forest land surrounding each forest pixel (a square approximately 30 meters on each edge) for
25 various landscape sizes (known as "windows") provides a synoptic assessment of forest fragmentation for
26 the contiguous United States by assessing each pixel's "forest neighborhood" within various distances.
27 Results are based on four degrees of forest cover: "core" if a subject pixel is surrounded by a completely
28 forested landscape (no fragmentation), "interior" if a subject pixel is surrounded by a landscape that is 90
29 to 100 percent forested, "connected" if a subject pixel is surrounded by a landscape that is 60 to 90
30 percent forest, and "patchy" if the subject pixel is surrounded by less than 60 percent forest. The window
31 (landscape) size used for this analysis was 9 by 9 pixels, 270 meters on each edge (percent forest was
32 resampled from 30 meter pixel data and aggregated by State to develop the EPA Region-specific
33 breakouts), or about 5900 hectares (14,500 acres). The window is shifted one pixel at a time over the map,
34 so the target population for the indicator is all forested pixels in the contiguous United States.
35 What the Data Show
36 Slightly more than 21 percent of the forested pixels in the U.S. represent "core" forest, which appear as
37 landscapes dominated by forest (Exhibit 6-5). However, the data for "interior" and "core" forests suggest
38 that fragmentation is extensive, with few large areas of complete, un-perforated forest cover. About 47
39 percent of forest pixels in the U.S. occur in a landscape where less than 60 percent of the "neighborhood"
40 is forest (i.e., forest cover is "patchy").
41 There is considerable regional variation in forest fragmentation (Exhibit 6-5). Regions 1, 2, 3, and 10
42 have more than 30 percent "core" forest pixels, while less than 10 percent of the forest pixels in Regions 7
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1 and 9 are "core" forest. From the opposite perspective,
2 fewer than 17 percent of forest pixels are surrounded by
3 less than 60 percent forest in Region 1, while almost 80
4 percent of the forest pixels in Region 7 are surrounded
5 by less than 60 percent forest.
6 Indicator Limitations
7 • Trend information is not available for this
8 indicator. The 1992 NLCD data on which
9 this indicator is based derive from satellite
10 imagery that is more than a decade old.
11 Trends in this indicator will depend on the
12 availability of NLCD data in the future.
13 • The degree of connectivity is dependent on
14 the size of the window: Riitters (2003)
15 determined that the percentages for all
16 categories (especially "core" and
17 "connected" forest pixels) decrease rapidly
18 as the size of the window is increased
19 progressively from 18 to 162, 1459, and
20 13132 acres.
21 • Because the non-forest land cover classes
22 were aggregated, this indicator does not
23 distinguish between natural and
24 anthropogenic fragmentation (although
25 such a distinction has been made for global
26 fragmentation by Wade et al., 2003).
27 • Fragmentation by roads is only partly
28 captured using NLCD maps, which show
29 some roads, but not all. Excluding such
30 roads probably underestimates
31 fragmentation on most public forest lands
32 (Riitters et al., 2004).
33 • The 1992 NLCD data do not include
34 Hawaii or Alaska, which account for about
35 one out of every six acres of forest land in
36 the United States.
37 Data Sources
Exhibit 6-5. Forest fragmentation in the
contiguous U.S. by EPA Region, based on
1992 NLCD3
Degree of forest cover:b
Core
Interior
Connected
Patchy
Percent of forested pixels in each category:
Region 1
Region 2
Region 3
Region 4
Region 5
39.2
35.8
33.7
27.0
14.6 13.2
12.f
16.C
16.6
17.0
24.2
20.3 16.3
i 15.2
36.5
) 18.6 31.7
20.8
35.6
55.1
Region 6
Region 7
Region 8
Region 9
Region 10
All U.S.
19.0
7.9
>D10.2
14.8 11
10.0
12.9
3.6
9
14.9
56.6
77.0
19.3
20.5
30.4
21.4
18.5
13.7 18.1
Coverage: Areas ol the contiguous
48 states classified as "forested" by
54.0
56.7
20.3
D
30.8
46.9
EPA Regions
® h&(^
the 1992 National Land Cover
Dataset (NLCD).
bSee text for definitions of forest
cover categories.
Data source: Riitters, 2003
38 This analysis was previously published in Riitters (2003) and Heinz Center (2005), with results presented
39 for the nation as a whole or broken down by Forest Service RPA region. EPA calculated results by EPA
40 Region based on the national map provided by Riitters (2003). The original analysis is based on land
41 cover data from the National Land Cover Dataset (USGS, 2005).
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1 References
2 Fahrig, L. 2003. Effects of habitat fragmentation on biodiversity. Annu. Rev. Ecol. Evol. Syst. 34:487-
3 515.
4 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. Forest pattern and
5 fragmentation. In: The state of the nation's ecosystems: measuring the lands, waters, and living resources
6 of the United States. New York, NY: Cambridge University Press, September 2002. Web update 2005.
7
8 Riitters, K.H. 2003. Report of the United States on the criteria and indicators for the sustainable
9 management of temperate and boreal forests, criterion 1: conservation of biological diversity, indicator 5:
10 fragmentation of forest types. Final report. FS-766A. In: Darr, D., ed. Data report: a supplement to the
11 National Report on Sustainable Forests. Washington, DC: USDA Forest Service.
12
13 Riitters, K., J. Wickham, and J. Coulston, J. 2004. Use of road maps in national assessments of forest
14 fragmentation in the United States. Ecol. Soc. 9(2): 13.
15
16 Riitters, K.H., J.D. Wickham, RV. O'Neill, K.B. Jones, E.R. Smith, J.W. Coulston, T.G. Wade, and J.H.
17 Smith. 2002. Fragmentation of continental United States forests. Ecosystems 5:815-822.
18
19 USDA Forest Service. 2004. National report on sustainable forests—2003. FS-766.
20
21 USGS. 2005. National Land Cover Dataset 1992 (NLCD 1992). Accessed 2005.
22
23 Wade, T.G., K.H. Riitters, J.D. Wickham, and K.B. Jones. 2003. Distribution and causes of global forest
24 fragmentation. Conserv. Ecol. 7(2):7.
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NDICATOR: Ecological Connectivity in EPA Regio
2 As part of their natural functioning, ecological systems remove particulate matter and carbon dioxide
3 from the air, purify surface and ground water, reduce flooding, and maintain biological diversity. These
4 functions depend on a connected ecological "framework" of high-quality land consisting of central hubs
5 interconnected by corridors that provide for the movement of energy, matter, and species across the
6 landscape. This framework of connectivity is threatened by agricultural and silvicultural practices, road
7 development, and "urban sprawl" that fragment the landscape and threaten the ecological framework.
8 Maintaining ecological connectivity protects the entire system.
9 The Ecological Connectivity Indicator (ECI) developed by EPA Region 4 (Durbrow et al, 2001) consists
10 of a framework that captures the connectivity of important natural areas and ecological systems across the
11 landscape of the Region (i.e., in Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South
12 Carolina, and Tennessee). Four ecological aspects contribute to the functionality of the ECI infrastructure
13 (see Carr et al., 2002, for additional details). The most important of the four, Hub and Corridor
14 Connectivity, forms the basis for this indicator. Hub and Corridor Connectivity shows the connections
15 among critical ecological systems in the Region. Hubs are large areas of important natural ecosystems
16 such as the Okefenokee National Wildlife Refuge in Georgia and the Osceola National Forest in Florida.
17 Connections, referred to as "corridors," are links to support the functionality of the hubs (e.g., the
18 Pinhook Swamp which connects the Okefenokee and Osceola hubs). The ECI framework is based on land
19 cover data obtained from the 1992 National Land Cover Dataset (NLCD), which was constructed from
20 satellite imagery (Landsat) showing the land area of the contiguous U.S. during different seasons (i.e.,
21 leaves-on and leaves-off) during the early 1990s. In many locations, the best available Landsat images
22 were collected between 1991 and 1993, with data in a few locations ranging from 1986 to 1995.
23 What the Data Show
24 The hub and connection framework covers 43 percent of the total land and water resources in EPA
25 Region 4—30 percent classified as hubs and 13 percent as corridors (Exhibit 6-6). Currently, 22 percent
26 of this framework area is protected as conservation land, 12 percent is in the public domain as open water,
27 and an additional 14 percent is classified as wetlands, for a total of 48 percent of hub and corridor acreage
28 being afforded some type of long-term protection.
29 Indicator Limitations
30 • Trend information is not available for this indicator. The most important data layer used in
31 the ECI development is the National Land Cover Data (NLCD) from 1992-93. Establishing
32 trends in the indicator will be limited by the availability of comparable land cover/land use
33 data for the period 2002 and beyond.
34 • Due to both the limited availability of data (ecological data not available or not in digital or
35 GIS format) and the Southeastern Ecological Framework (SEF) parameter that sets a size
36 threshold of 5,000 acres for ecological hubs, the results do not comprehensively include each
37 and every ecologically important area in the Southeast.
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Exhibit 6-6. Ecological hubs and corridors in EPA Region 4,
based on 1992 NLCD
Surface area of Region 4
(land + water)
Not hubs
or corridors
57%
Protected status of hubs
and corridors
Existing
conservation
lands
22%
Unprotected
52%
12%-
14%-
—. Open waters in the public domain
(outside conservation lands)
Wetlands
(outside conservation lands)
Data source: U.S. EPA Region 4, Southeastern Ecological Framework project. Based on
1992 National Land Cover Dataset (NLCD) and other data described in Carr et at., 2002.
Data Sources
The hub and corridor map was provided
by U.S. EPA Region 4's Southeastern
Ecological Framework (SEF) project,
and is available as a GIS data layer
from the SEF website's data page (U.S.
EPA, 2002)
(http://geoplan.ufl.edu/epa/data.html).
The summary statistics shown in the pie
charts in Exhibit 6-6 are presented in
Carr et al. (2002). This analysis was
based on the 1992 NLCD (USGS, 2005)
(http://landcover.usgs. gov/natllandcover
.php) and several additional datasets
described in Carr et al. (2002); input
data layers can be obtained on CD by
following instructions on the SEF
website (U.S. EPA, 2002).
References
Carr, M.H., et al. 2002. Final report:
Southeastern Ecological Framework.
Region 4. Atlanta, GA: U.S.
Environmental Protection Agency.
26 Durbrow, B.R., N.B. Burns, J.R. Richardson, and C.W. Berish. 2001. Southeastern Ecological
27 Framework: a planning tool for managing ecosystem integrity. In: Hatcher, K.J., ed. Proceedings of the
28 2001 Georgia Water Resources Conference. Athens, GA: University of Georgia.
29 U.S. EPA. 2002. The EPA Southeastern U.S. Ecological Framework project.
30
31 USGS. 2005. National Land Cover Dataset 1992 (NLCD 1992). Accessed 2005.
32
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3 Ecological condition in EPA's Report on the Environment is approached using questions broadly relating to
4 landscape, biological diversity, ecological function, and the physical and chemical make-up of the
5 environment, but no attempt is made at the national level to capture ecological condition in a small number of
6 indices. In this indicator, the ecological condition of undeveloped land in EPA Region 5 (Illinois, Indiana,
7 Michigan, Minnesota, Ohio, and Wisconsin) is characterized based on three indices derived from criteria
8 representing diversity, self-sustainability, and the rarity of certain types of land cover, species, and higher taxa
9 (White and Maurice, 2004).
10 Geographic units referred to as cells are used to quantify geographic information. A spatially explicit model
11 using ecological theory and geographic information system (GIS) technology was used to create twenty data
12 layers of 300m x 300m cells from the 1992 National Land Cover Dataset (NLCD), which was constructed
13 from satellite imagery (Landsat) showing the land area of the contiguous U.S. during different seasons (i.e.,
14 leaves-on and leaves-off) during the early 1990s. In many locations, the best available Landsat images were
15 collected between 1991 and 1993, with data in a few locations ranging from 1986 to 1995. For this indicator,
16 NLCD data were used to generate three indices, which represent estimates of three criteria:
17
18
19
20
21
22
23
24
25
Ecological Diversity -the relative diversities of populations (species), communities, and
ecological systems in any given location on the landscape. Four data layers were used to
derive this index.
Ecological Self-Sustainability - the potential for an ecological system to persist for years
without external management; it is negatively impacted by two factors: landscape
fragmentation and the presence of chemical, physical, and biological stressors. Twelve data
layers were used to derive this index.
Rarity - the rarity of land cover, species, and higher taxa. Four data layers were used to derive
this index.
26 The model produces composite layers that are statistically independent. The scores for each criterion are
27 normalized from 1 to 100 and each layer contributes equally to the final index (all of the data layers are
28 weighted equally). In all the data layers and the resultant criteria layers, scores are normalized from 0 to 100.
29 Zero always indicates the lowest quality, the greatest stress, or the least valuable observation, and 100
30 indicates the highest quality, least stress, or most valuable observation. While it has not been done for this
31 indicator, the three composite scores can be summed to result in a final "ecological condition" score for each
32 cell (White and Maurice, 2004). Cell counts (a measure of geographic coverage) are used to indicate the
33 distributions of scores associated with three index scores of ecological condition of undeveloped land:
34 diversity, sustainability, and rarity.
35 What the Data Show
36 The frequency distributions of the 1992 baseline scores are quantified and plotted for each criterion (Exhibit
37 6-7), and these provide a baseline against which to track future landscape trends in diversity, sustainability,
38 and rarity. Diversity scores generally run from 20 to 80 across the region, signifying that most areas are in the
39 moderate diversity range. More than 90 percent of the region has sustainability scores above 50, but rarity
40 scores above 50 are seldom encountered. The majority of undeveloped land in Region 5 (which has higher
41 index scores) lies in the northern forests of Minnesota, Wisconsin, and Michigan and along the large rivers in
42 Ohio, Indiana, and Illinois (Exhibit 6-8).
43
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Exhibit 6-7. Distribution of index scores for the
relative ecological condition of undeveloped
land in EPA Region 5, 1990-1992a
150,000
"° 100,000
2
g 50,000
A. Diversity index
^ 250,000
200,000
40 60
Index score
B. Sustainability index
40 60
Index score
C. Rarity index
Area (number of cells
DUU.UUU
400,000
200,000
0
\
\J VJL
) 20 40 60 80 1C
Index score
"Coverage: Undeveloped land in EPA Region 5, based on the
1992 National Land Cover Dataset (NLCD). For this analysis,
"undeveloped" land Is any land that the NLCD classifies as bare
rock/sand/clay, deciduous forest, evergreen forest, mixed forest,
shrubland, grasslands/herbaceous, woody wetlands, emergent
herbaceous wetlands, or open water.
Data source: U.S. EPA Region 5
Exhibit 6-8. Relative ecological condition of undeveloped land
in EPA Region 5, 1990-1992a
B. Sustainabilily index
C. Rarity index
Index score:
Low
'Coverage: Undeveloped land in EPA Region 5, based on the 1992 National Land Cover
Dataset (NLCD). For this analysis, "undeveloped" land is any land that the NLCD
classifies as bare rock/sand/clay, deciduous forest, evergreen forest, mixed forest,
shrubland, grasslands/herbaceous, woody wetlands, emergent herbaceous wetlands,
or open water.
0a/3 source: U.S. EPA Region 5
Indicator Limitations
Trend information is not available for this
indicator. The ability to track trends will be
dependent on the comparability of the 2001
round of the NLCD with the 1992 NLCD
data used to develop this indicator.
• Although this indicator is designed to be
comparable across undeveloped land within
Region 5, layers were ranked within ecoregions for some of the indicators in order to account
for different geophysical, geochemical, or climatic features of each ecoregion.
• Aquatic systems and connectivity resulting from water flow paths are not adequately covered
and small, but potentially keystone, systems are not a part of the analysis (U.S. EPA, 2005).
• Equal weighting of the data layers that contribute to each index may not be representative of
the relative importance of each layer (U.S. EPA, 2005).
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1 • The resolution and uncertainty of the results make comparing the ecosystem condition score
2 for one individual cell (300m x 300m) with another inappropriate, but this is not the case for
3 comparison between larger landscapes (U.S. EPA, 2005).
4 • Field validation of the model to insure that modeled results are reflective of actual ecosystem
5 condition will not be completed until the summer of 2006.
6 Data Sources
7 Maps and frequency distributions for the three indices were provided by EPA Region 5. An EPA report
8 available online contains several related maps produced by the Critical Ecosystem Assessment Model
9 (CrEAM), along with a list of the various datasets used as inputs for the model (White and Maurice, 2004
10 [appendices]). Results from the CrEAM model are no longer available as digital map layers.
11 References
12 U.S. EPA. 2005. SAB review of the EPA Region 5 Critical Ecosystem Assessment Model.
13 EPA/SAB/05/011. Washington, DC.
14 White, M.L., and C. Maurice. 2004. CrEAM: a method to predict ecological significance at the landscape
15 scale. Chicago, IL: U.S. Environmental Protection Agency.
16 (text);
17 (appendices)
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1 6.2.3 Discussion
2 What These Indicators Say about Trends in Extent and Distribution of the
3 Nation's Ecological Systems
4 While ecological systems are interconnected and overlapping, it is useful to discuss trends in terms of
5 major types of systems. There are many ways to define ecological systems, including by the predominant
6 biota, spatial scales, and physical characteristics. Most terrestrial systems are defined by predominant
7 vegetation types. The current extent of these types has been assessed (see Land Cover indicator, p. 4-11).
8 Forests form the predominant land cover in the eastern and northwestern United States while grasslands,
9 shrublands, and agricultural lands are the predominant types of vegetation in the central and western parts
10 of the country. Trends in forest and wetland ecological systems are considered below. Trends in land
11 development also are discussed, as this influences trends in the extent of ecological systems.
12 Trends in Extent and Distribution of Forested Ecological Systems
13 At a national scale, the percentage of forest land has varied somewhat over the last century with some
14 decreases and some recent increases (see Forest Extent and Type indicator, p. 6-14, and Forest
15 Fragmentation indicator, p. 6-17). However, shifts in regional distribution, of tree species and age
16 structure have occurred. Forested ecological systems have decreased in extent in EPA Regions 6 and 9
17 but increased in extent in Regions 3 and 5. The complex of tree species within a forest can have a strong
18 influence on the community structure and functioning of a forested ecological system. These assemblages
19 change over time, however this change may not be detectable at a national scale. On the scale of broad
20 geographical regions, the Maple-Beech-Birch cover type has increased in acreage since 1992 in the
21 Northern U.S., while a number of spruce and pine species cover types have decreased in the West These
22 compositional changes can be as important as changes in the overall extent of forested ecological systems.
23 Age structure differences are also apparent among regions with younger trees in the East and older trees
24 in the West.
25 At a finer regional scale, forest cover in the Puget Sound and Georgia Basin in the Pacific Northwest also
26 was relatively stable during the 1990s (see Land Cover in Puget Sound/Georgia Basin indicator, p. 4-17).
27 However, some of the forested watersheds experienced a conversion of small amounts of forest land to
28 some other cover type. As discussed below, urbanization of low-elevation forested watersheds is a change
29 that is receiving particular attention (see Land Cover in Puget Sound/Georgia Basin indicator, p. 4-17).
30 While extent and species composition are important aspects of forested ecological systems, the spatial
31 arrangement and contiguity of the systems also influence the functioning of the systems and the
32 distribution of wildlife species that use forests and adjacent areas for habitat. Fragmentation of forested
33 systems can reduce or redefine the interconnections within forests, modifying the scale of habitat and
34 shifting distributions of wildlife species. For example, increasing fragmentation due to forest clearing,
35 development, fires, or other activities creates more edge habitat and limits the acreage of interior habitat.
36 Groups of wildlife species may prefer one habitat over another and move to maximize the time spent in
37 the preferred habitat type. Nationwide, almost half of forests are highly fragmented or "patchy," although
38 more than 30 percent of the forests in the heavily forested Regions 1, 2, 3, and 10 are virtually
39 unfragmented "core" forest (see Forest Fragmentation indicator, p. 6-17). The majority of forest
40 fragmentation in the eastern United States is anthropogenic, while most fragmentation in the West is
41 caused by natural factors.
42 Ecosystem connectivity, the degree to which ecosystem "hubs" are connected to each other by "spokes"
43 that serve as corridors for the interaction of biota, was shown to account for about 40 percent of the land
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1 cover in EPA Region 4, the southeastern United States (see Ecological Connectivity in Region 4
2 indicator, p. 6-20). In this indicator, connectivity includes not only forested land but also wetlands and
3 open water. It may be coincidental that the degree of forest fragmentation is broadly similar to the degree
4 of ecosystem connectivity, but in both indicators about half of the ecosystems in the Southeast are
5 fragmented or unconnected.
6 Trends in Extent and Distribution of Wetland Ecosystems
1 Wetlands are ecosystems of high biological diversity and support a number of ecological functions from
8 nursery and breeding areas to food and protection.16 Whether inland or coastal, freshwater or marine,
9 wetlands acreage has been declining over the past 50 years (see Wetlands indicator, p. 3-53). The extent
10 of the losses varies by type of wetland, with forested wetlands losing the most acreage and coastal
11 wetland loss slowing somewhat.
12 Trends in Land Development
13 Land use refers to the visible effects of human use (see Land Use indicator, p. 4-24). Changes in land use
14 from forested or wetland systems to urban or agricultural environments have a direct impact on the
15 ecological systems within which the change occurs as well as on systems that are interconnected with the
16 altered areas (e.g., watersheds and coastal areas). Some changes can create edge environments that are
17 favored by certain wildlife species. Therefore, trends in land development are important considerations
18 with respect to overall trends in the extent and distribution of ecological systems.
19 Changes in land use sometimes result in changes in land cover and conversion from one major ecosystem
20 type to another, but sometimes they do not. For example, gains in agricultural productivity have caused
21 significant changes in the extent and location of crop and pasture land uses. Some land that had been used
22 for crops or pasture has reverted to forest. Timber production may convert cropland to forest, or it may do
23 little more than substitute one forest type or age-class distribution for another. At the same time, growth
24 in population has driven an increase in the extent of developed land, much of which has converted crop or
25 pasture land to developed land.
26 At a national scale, crop and farm acreages have decreased, timberland (productive forest land) has
27 remained constant since 1997, and developed lands have increased between 1982 and 2002 (see Land Use
28 indicator, p. 4-24). Within the larger scale trends, many subtle shifts occur at smaller scales. The increase
29 in developed lands has received particular attention in National and Regional Indicators.
30 Increases in the numbers and changes in the spatial distribution of human populations explain part of the
31 increase in developed lands. However, developed land increased by almost two times the increase in
32 population from 1982 to 2002 suggesting that during this period people were making a proportionally
33 greater use of the landscape (see Urbanization and Population Change indicator, p. 4-31). Geographically,
34 the rate of development was four times the population growth rate in the Northeast, one to three times the
35 population growth rate in the South and Midwest, and nearly equal to the growth rate in the West.17 The
16 Dahl, T.E. 2000. Status and trends of wetlands in the conterminous United States 1986 to 1997. Washington, DC:
U.S. Department of the Interior, U.S. Fish and Wildlife Service.
17 U.S. Census Bureau. 2004. Table 8: Annual Estimates of the Population for the United States, Regions, and
Divisions: April 1, 2000 to July 1, 2004. NST-EST2004-08. U.S. Census, Population Division.
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1 increases in developed land suggest there were comparable decreases in other types of lands. To the
2 extent that these other lands afford habitat to animals and plants, shifts in land use result in shifts in the
3 extent and distribution of ecological systems.
4 The degree of change in developed lands appears to be associated with types of locations which emerge
5 as focal points for increasing stress on ecological systems. For example, in the Puget Sound and Georgia
6 Basin area of the Pacific Northwest, forest conversion to other types of land use is occurring along the
7 coast while older growth forests are observed at higher elevations (see Land Cover in Puget
8 Sound/Georgia Basin indicator, p. 4-17). Further, trends indicate that impervious surface coverage is
9 increasing to the point where detrimental impacts to aquatic resources may occur.18 In the Great Lakes
10 region, most of the undeveloped lands occur in the northern forests or along the major rivers (see
11 Condition of Undeveloped Land in Region 5 indicator, p. 6-22). Proximity to developed areas has an
12 obvious effect on the quality of these ecological systems. The highest quality systems comprise about 3
13 percent of the total and are located in the most remote and/or protected areas. The potential for future land
14 use changes with increasing urbanization is the major determinant for judging potential fragmentation of
15 ecological systems in EPA Region 5 (Great Lakes area).
16 Limitations, Gaps, and Challenges
17 While many of the indicators in this section provide baseline information, trend information is available
18 for only a few of the major types of systems-forests and wetlands. There are no ROE indicators for other
19 types of terrestrial or aquatic systems including grasslands, shrublands, and marine hard bottom
20 communities including coral reefs. Filling these gaps in information would help EPA to better evaluate
21 trends in ecological condition.
22 One of the challenges in capturing meaningful changes relates to location and scale. The importance of
23 location-specific changes is evident in some of the indices. For example, small changes in certain areas,
24 such as near-coastal areas of the Pacific Northwest, could have disproportionately large effects on coastal
25 waters relative to a similar change in the middle of an expansive prairie. In addition, the appearance of
26 fragmentation in ecological systems depends on the area over which data were extracted.19 Thus,
27 choosing locations and assessment areas have obvious impacts on trend assessment. Conversely, the
28 implications of trends are manifested at scales that are location- and area-specific. Important
29 consequences of changes can be captured or missed depending on how the information is aggregated and
30 presented.
31 Another challenge relates to understanding the factors underlying changes that occur over various time
32 scales and their effects on human health and ecological condition. Principal among these is recognizing
33 that natural cycles and natural variability bring about changes that may appear as "trends" over one time
34 scale but will appear as cycles or variations over longer time scales. Familiar examples include population
35 variations among predators and prey or temperature variations associated with the advance and retreat of
36 ice ages. Distinguishing these natural cycles and variations from trends caused by human-induced
37 perturbations is yet another challenge. In some cases the relationships may be evident, as in the influence
38 of urbanization on watersheds or the impact of lost sand dunes on subsequent beach erosion. In other
18 Klein, R.D. 1979. Urbanization and stream water quality impairment. Water Resour. Bull. 15(4):948-963.
19 USDA Forest Service. 2004. National report on sustainable forests—2003. FS-766. Washington, DC. p. 19.
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1 cases factors influencing changes may be difficult to discern, such as long-term shifts in major plant
2 communities.
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1 6.3 WHAT ARE THE TRENDS IN THE DIVERSITY AND BIOLOGICAL BALANCE
2 OF THE NATION'S ECOLOGICAL SYSTEMS?
3 6.3.1 Introduction
4 Trends in the biological diversity of the nation's ecological systems can be viewed in terms of both the
5 numbers of species present in an ecological system and the extent to which some of the species are
6 threatened or endangered. Biological balance refers to the inter-relationships among organisms, including
7 the structure of food webs and the ability of ecological systems to maintain themselves over time. Balance
8 is a dynamic characteristic rather than a fixed state.
9 The biological diversity and balance within ecological systems are often used to judge the health of the
10 system, and their reduction often represents a response to pollutants or other stressors. Restoring
11 biodiversity and biological balance have constituted a focus of EPA's attention over the past three
12 decades. Reversing declines of species such as the brown pelican caused by pesticides and brook trout
13 caused by acid rain, replacing nuisance algal blooms caused by excess nutrients with balanced
14 communities of phytoplankton, replacing beds of sludgeworms due to sewage discharges with balanced
15 communities of benthic invertebrates, and restoring biological communities previously decimated by
16 improper handling of toxic and hazardous wastes are well-known examples.
17 The significance of biological diversity also stems from the fact that, for many people, biological
18 diversity contributes to the quality of life.20 Everyone recognizes the importance of species as
19 commodities (if those species produce products that can be bought and sold), and some argue that species
20 have moral value in and of themselves.
21 Diversity and biological balance are also of interest because of how they may influence the functioning
22 and stability of ecological systems.21'22 While scientists debate the exact relationship between the
23 diversity and the functioning and stability of ecological systems, it is generally agreed that as the number
24 of species in any particular type of ecological system declines, there is a potential loss of "resilience"
25 within that system.23. It is also recognized that these relationships are not straightforward and can vary in
26 degree depending on the types of species introduced or removed from a system.24
27 Diversity and balance have important time and space components. Diversity arises over time as
28 adaptation results in new species that fill available "niches" in the environment. This is a dynamic process
29 involving colonization, evolution of species adapted to new conditions, and extinction of species that are
30 less well adapted to a changing environment. This process has occurred over thousands or millions of
20 Norton, B. 1988. Commodity, amenity, and morality: the limits of quantification in valuing biodiversity. In:
Wilson, E.O., ed. Biodiversity. Washington, DC: National Academy Press, p. 521.
21 Chapin III, F.S., et al. 1997. Biotic control over the functioning of ecosystems. Science 277(5325): 500-504.
22 Wilson, E.G. 1992. The diversity of life. Cambridge: Belknap Press, 1992.
23 McCann, K.S. 2000. The diversity-stability debate. Nature 405(11): 228-233.
24 Srivastava, D.S. and M. Vellend. 2005. Biodiversity-ecosystem function research: Is it relevant to conservation?
Annu. Rev. Ecol. Syst. 36: 267-294.
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1 years over large geographic areas, punctuated occasionally by large events such as meteor strikes, periods
2 of intense volcanism, and ice ages. Ecological systems that are stable in the short term evolve into
3 different systems in the long term. Disturbances that reduce biological diversity or disrupt balance on a
4 small scale may not have an effect on a larger scale or over longer time periods.
5 Changes (decreases and increases) in biological diversity have likely occurred throughout the history of
6 the United States in response to regional land use changes (e.g., the reforestation of the Southeast during
7 the past century), water management, intentional and unintentional introductions of species, and
8 environmental pollution. Other changes in diversity and the composition of the biological community can
9 be rapid and dramatic. Introduced plants and plant pathogens can rapidly transform landscapes as some
10 species, such as the American chestnut, are lost and others, such as kudzu, thrive. Introduction of the sea
11 lamprey to the Great Lakes led to sweeping changes in the entire food chain, from lake trout all the way
12 down to the phytoplankton.25 Declining sea otter populations led to loss of kelp forests, as sea urchins
13 formerly preyed upon by otters grazed the kelp down to the sea floor.26 The decimation of grazers such as
14 the American Bison or predators such as grizzly bear or wolves has had cascading impacts on upland
15 vegetation, wetlands, fish, and other species.27 Toxic chemical pollution can create wastelands where only
16 the most resistant species can survive, and nutrients and acid rain have had indirect effects on diversity
17 and balance by causing sweeping changes in the chemical habitat.
18 Indicators of diversity and biological balance incorporate information about primary producers and
19 invertebrate and vertebrate consumers, especially keystone species which play critical roles in structuring
20 habitat or serve major roles as primary producers, top predators, or important prey species. Indicators of
21 invasive species are also important with respect to assessing trends in the diversity and biological balance
22 because these species can alter the nation's ecological systems by displacing indigenous species,
23 potentially changing the structure of biological communities.
24 6.3.2 ROE Indicators
25 Trends in diversity and balance are evaluated from four National Indicators and three Regional Indicators
26 (Table 6.3.1). The focus for this question is on national- or regional-scale trends in biological diversity or
27 balance over time spans of one to three decades. The data on biological diversity and balance come from
28 a variety of sources, including both systematic monitoring and ad hoc data collection.28 Systematic
29 probability surveys are now providing national pictures of the biological diversity of benthic communities
30 in estuaries and in rivers and streams. The Breeding Bird Survey is a private sector effort that provides
31 valuable national-level data on trends in bird populations.
25 Eck, G. W., and L. Wells. 1987. Recent changes in Lake Michigan's fish community and their probable causes,
with emphasis on the role of the alewife (Alosa pseudoharengus). Can. J. Fish. Aquat. Sci. 44(Suppl. 2):53-60.
26 Estes, J.A., and J.F. Palmisano. 1974. Sea otters: their role in structuring nearshore communities. Science
185:1058-1060.
27 Pritchard, J.A. 1999. Preserving Yellowstone's natural conditions: science and the perception of nature. Lincoln,
NE: University of Nebraska Press, p. 370.
28 There are no systematic national efforts to quantify trends in the diversity of other vertebrate, invertebrate, plant,
or microbial species, but a private sector organization, NatureServe, working in concert with state Natural Heritage
Programs, has done much to assimilate and integrate data from ad hoc studies to quantify populations of more than
200,000 species in the United States.
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1
2
3
4
5
Trends involving longer-term effects associated with climate change are not included. Many issues
regarding biodiversity at subregional and local scales (e.g., tall grass prairie or the Okefenokee Swamp)
that cannot be covered here are no less important.
Table 6.3.1. ROE Indicators of Trends in Diversity and Biological Balance of the Nation's
Ecological Systems
NATIONAL INDICATORS
Coastal Benthic Communities (N/R)
Benthic Macroinvertebrates in Wadeable Streams
Bird Populations
Fish Faunal Intactness
REGIONAL INDICATORS
Submerged Aquatic Vegetation (SAV) in the Chesapeake Bay
Harmful Algal Bloom Outbreaks Along the Western Florida Coastline
Non-Indigenous Species in the Estuaries of the Pacific Northwest
LOCATION
3.5.2 -p. 3-71
3.2.2 -p. 3-35
6.2.2 -p. 6-32
6.2.2 -p. 6-34
3.5.2 -p. 3-74
3.5.2 -p. 3-81
6.2.2 -p. 6-37
6
7
N/R = National Indicator displayed at EPA Regional scale
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INDICATOR: Bird Populations
2 Bird populations are among the most visible and important biological components of ecological systems
3 and support a number of important ecological functions including seed dispersal, plant pollination and
4 pest control. Some birds migrate over entire continents, while others have more restricted ranges and
5 habitats, but in all cases trends in bird populations and in the abundance of species integrate the influences
6 of changes in landscape and habitat, the availability and quality of food, toxic chemicals, and climate. The
7 North American Breeding Bird Survey (BBS) began in 1966 with approximately 600 surveys conducted
8 in the U.S. and Canada east of the Mississippi River. Today there are approximately 3,700 active BBS
9 routes across the continental U.S. and southern Canada (Sauer et al., 1997).
10 Trends have been computed for observed population sizes of 418 bird species for the period 1966-2003
11 (Sauer et al., 2004). The Audubon Society (2004) categorized each species according to its primary
12 habitat: grassland, shrubland, woodland, urban, and water and wetlands. This indicator reflects the
13 number of species with "significant" increases or decreases in the number of observations (not a change
14 in the number of species) for which adequate trend data exist between 1996 and 2003. Significant
15 increases or decreases were defined for this study as those in which the observed populations on BBS
16 routes increased or decreased by more than two-thirds between 1966 and 2003 and does not necessarily
17 imply a statistically significant trend.
Exhibit 6-9. Changes in bird populations in the
contiguous U.S. and southern Canada, by
habitat type, 1966-20033
^UU
•lye
icn
z 15°
m 17e
Urban
Water/
wetland
Coverage: 418 bird species studied as part
of the North American Breeding Bird Survey
(BBS), which covers the contiguous U.S.
and southern Canada.
"increases or decreases are considered
"substantial" if the observed population on
BBS routes increased or decreased by more
than two-thirds from 1966 to 2003.
Data source: Audubon Society, 2004
What the Data Show
The results point to dynamic changes in bird
populations in all habitat types (Exhibit 6-9), although
there were no consistent increases or decreases.
• Of 27 grassland species for which
adequate data are available, only 2 species
(7 percent) showed significant population
increases and 19 species (70 percent)
showed significant decreases.
• Of 78 shrubland species for which
adequate data are available, 11 species (14
percent) showed significant increases,
while 28 species (36 percent) showed
significant declines.
• Of 164 woodland species for which
adequate data are available, 48 species (29
percent) showed significant population
increases and 42 species (26 percent)
showed significant decreases.
• Of 43 primarily urban species for which
adequate data are available, 17 species (40
percent) showed significant population
increases and 10 species (23 percent) had
significant decreases.
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1 • Of 106 water and wetland bird species for which adequate data are available, 40 species (38
2 percent) showed significant increases and 14 species (13 percent) showed significant
3 decreases.
4 Indicator Limitations
5 • The BBS produces an index of relative abundance rather than a complete count of breeding
6 bird populations. The data analyses assume that fluctuations in these indices of abundance are
7 representative of the population as a whole.
8 • The BBS data do not provide an explanation for the causes of population trends. To evaluate
9 population changes over time, BBS indices from individual routes are combined to obtain
10 regional and continental estimates of trends. Although some species have consistent trends
11 throughout the history of the BBS, most do not. For example, populations of permanent
12 resident and short-distance migrant species (birds wintering primarily in the U.S. and
13 Canada) are adversely affected by periodic episodes of unusually harsh winter weather.
14 • Few species have consistent population trends across their entire ranges, so increases or
15 decreases in this indicator may not reflect the situation across the entire range of the species.
16 Data Sources
17 Trend data were obtained from the Audubon Society's 2004 "State of the Birds" report (Audubon
18 Society, 2004). Audubon's analysis used raw data from the National Breeding Bird Survey (USGS,
19 2004), which can be downloaded from http://www.pwrc.usgs.gov/bbs/retrieval/menu.cfm.
20 References
21 Audubon Society. 2004. State of the birds USA 2004. Audubon Magazine September-October.
22
23 Sauer, J.R., J.E. Hines, and J. Fallen. 2004. The North American Breeding Bird Survey, results and
24 analysis 1966-2003. Version 2004.1. Laurel, MD: USGS Patuxent Wildlife Research Center.
25
26 Sauer, J.R., J.E. Hines, G. Gough, I. Thomas, and E.G. Peterjohn. 1997. The North American Breeding
27 Bird Survey, results and analysis. Version 96.4. Laurel, MD: USGS Patuxent Wildlife Research Center.
28
29 USGS. 2004. North American breeding bird survey. Laurel, MD: USGS Patuxent Wildlife Research
30 Center. Accessed 2004.
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INDICATOR: Fish Faunal Intactness
2 Intactness, the extent to which ecological communities have retained their historical composition, is a
3 critical aspect of the biological balance of the Nation's ecological systems (NRC, 2000). It is of particular
4 importance in freshwater systems that are impacted by pollution, habitat alteration, fisheries management,
5 and invasive species.
6 This indicator tracks the intactness of the native freshwater fish fauna in each of the nation's major
7 watersheds by comparing the current faunal composition of those watersheds with their historical
8 composition. In this case, historical data are based on surveys conducted in 1970. The indicator
9 specifically measures the reduction in native species diversity in each 6-digit USGS hydrologic cataloging
10 unit (HUC) in the 48 contiguous states. Intactness is expressed as a percent based on the formula:
11 reduction in diversity = 1 - (# of current native species / # of historic native species).
12 The native species diversity indicator proposed by the NRC (NRC, 2000) compared expected native
13 species diversity (projected from species-area-curve models) with observed diversity. This "Fish Faunal
14 Intactness" indicator makes use of empirical, rather than modeled, data sets and focuses on a well-known
15 group of organisms with a fairly strong historical record.
16 Reductions in watershed diversity may be due either to the overall extinction of a species (at least 12 U.S.
17 freshwater fish species are known to be extinct and another 3 species are known only from historical
18 records and may be extinct) or, more commonly, to the extirpation of a species from selected watersheds.
19 In the case of regional extirpations, opportunities may exist for restoring the species to watersheds in its
20 historic range.
21 The fish distributional data underlying this indicator were gathered by Nature Serve, a non-profit research
22 organization, and are derived from a number of sources, including species occurrence data from state
23 natural heritage programs, a broad array of relevant scientific literature (e.g., fish faunas), and expert
24 review in nearly every state. These data were assembled during the period 1997-2003. The underlying
25 data include distributions for 782 native freshwater fish species across small watersheds (8-digit HUC).
26 For this indicator, data were pooled and reported by larger 6-digit HUCs to reduce potential errors of
27 omission in the smaller watersheds.
28 What the Data Show
29 Watersheds covering about one-fifth (21 percent) of land area in the contiguous United States are fully
30 intact, retaining their entire complement offish species (Exhibit 6-10). Watersheds covering nearly a
31 quarter (24 percent) of land area, however, have lost 10 percent or more of their native fish fauna since
32 1970. Reductions in diversity are especially severe in the Southwest (e.g., the lower Colorado River
33 watershed) and the Great Lakes, with eight major watersheds (representing 2 percent of total land area)
34 having lost more than half of their native fish fauna.
35 Because the indicator is expressed as a ratio, it does not reflect the magnitude of species losses in a given
36 watershed. The southeastern United States, for instance, is far richer in numbers of freshwater fish species
37 by HUC than the southwestern United States (Exhibit 6-11). Although some southeastern HUCs have
38 experienced losses in the absolute number of species (e.g., in the state of Mississippi), due to the large
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1 number of species overall, the fish fauna can still appear relatively intact when viewed on a percentage
2 rather than numeric basis.
Exhibit 6-10. Percent reduction in native fish species diversity in the contiguous U.S. from 1970
to 1997-2003'
7% of
15% Of |and
land area ^ area
—2% of
land
21% of ' area
land area
sData are displayed by 6-digit hydrologic unit code (HUC) watershed. Percent reduction is based on the number of
native species present during the period 1997-2003, compared with the number present in 1970. A species is
considered "present" if there is at least one record of its presence in any 8-digit HUC within the 6-digit HUC.
Data source: NatureServe
Exhibit 6-11. Historical diversity of native fish species in the
contiguous U.S., 1970;i
Number of species:
• 0-24
25-48
49-90
91-133
• 134-178
''Data are displayed by 6-digit hydrologic unit code (HUC) watershed.
Data source: NatureServe
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1 Indicator Limitations
2 • The incomplete historical record for freshwater fish distributions and inconsistent inventory
3 records for contemporary fish distributions are sources of uncertainty.
4 • Although NatureServe has attempted to compile the most complete distributional information
5 possible for these species at the 8-digit HUC level, these data are dynamic; new records
6 frequently are added and existing records are revised as new information is received and as
7 taxonomic changes occur. Consequently, these distributional data could benefit from
8 additional quality control, updating, and expert review.
9 Data Sources
10 This indicator presents a summary of data available from the NatureServe Explorer database
11 (NatureServe, 2006) (http://www.natureserve.org/getData/dataSets/watershedHucs/index.jsp'). The
12 identity and status (current vs. historical) of all native fish species recorded in each 8-digit HUC are
13 available from this database, along with species-by-species distribution maps at the 8-digit HUC level.
14 Analyses based on these data have previously been reported in Master et al. (1998), Master et al. (2003),
15 and Stein etal. (2000).
16 References
17 Master, L., A. Olivero, P. Hernandez, and M. Anderson. 2003. Using small watershed fish, mussel, and
18 crayfish historical and current presence data to describe aquatic biogeography and inform its
19 conservation. Abstract #PO67. Society for Conservation Biology Annual Meeting, Duluth, Minnesota.
20 Master, L.L, S.R. Flack, and B.A. Stein. 1998. Rivers of life: critical watershed for protecting freshwater
21 biodiversity. Arlington, VA: The Nature Conservancy.
22
23 NatureServe. 2006. NatureServe explorer. Accessed 2006.
24 NRC (National Research Council). 2000. Ecological indicators for the nation. Washington, DC: National
25 Academy Press,
26 Stein, B.A., L.S. Kutner, and J.S. Adams. 2000. Precious heritage: the status of biodiversity in the United
27 States. New York, NY: Oxford University Press.
28
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INDICATOR: Non-Indigenous Species in the Estuaries of the Pacific NorthwesJ
2 Non-indigenous species (NIS) are one of the greatest threats to aquatic ecosystems and can impact local
3 and regional economies (Lowe et al., 2000). The number of invasive species in estuaries of the Pacific
4 Northwest (including Puget Sound, Columbia Estuary, and Coos Bay) is rising and these areas can then
5 become sources of invasives to other locales. Coastal waters are particularly vulnerable to NIS
6 transported in ballast water and introduced via aquaculture (Puget Sound Action Team, 2002). It is
7 becoming apparent that NIS are capable of impacting estuaries along the west coast, even though they are
8 rarely addressed in routine monitoring studies. One limitation is the lack of standardized invasion metrics
9 and threshold values.
10 This indicator focuses on estuarine soft-bottom communities of the Columbian Biogeographic Province
11 located along the Pacific coast from Cape Mendocino, CA north to the Strait of Juan de Fuca at the
12 entrance to Puget Sound, WA. It is limited to sites with salinities >= 5 parts per thousand. The indicator is
13 based on the percent abundance of NIS individuals relative to the combined abundance of native and NIS
14 individuals in a benthic grab sample.
15 The data for this indicator were collected by the Environmental Monitoring and Assessment Program
16 (EMAP) using a probability design over the period 1999-2001 (Nelson et al., 2004; in review) and by a
17 special study focusing on estuaries not exposed to ballast water or aquaculture. Probability sampling
18 provides unbiased estimates of the percent abundance of natives and NIS in all estuaries in the study area,
19 but, because the data for the special study have not yet been statistically expanded, data for this indicator
20 is based on stations sampled rather than area.
21 Background levels for the indicator are based on observations in estuaries with minimal exposure to invasion
22 from ballast water discharges or to aquaculture of exotic oysters. Three threshold levels of invasion were
23 assigned to the indicator: "minimally invaded" or "background" when NIS constituted a small proportion
24 of the individuals (0-10 percent), "highly invaded" when the NIS were the numerical dominants (>50
25 percent of the individuals), and "moderately invaded" when the NIS were relatively abundant but not the
26 numerical dominants (10-50 percent of the individuals). Estuaries were further classified into "exposed"
27 and "minimally exposed. "Exposed" estuaries are those exposed to ballast water discharges from
28 international shipping and/or aquaculture of exotic oysters. "Minimally exposed" estuaries are those
29 without international shipping or oyster culture, though there may have been historical exposure as well
30 as exposure through regional fishing boats.
31 What the Data Show
32 Approximately 15 percent of the stations in the Columbian Province were highly invaded (abundance of
33 NIS > abundance of natives) and another 20 percent were moderately invaded (Exhibit 6-12). The study
34 showed that non-indigenous species were among the most frequently occurring anthropogenic stressors in
35 this biogeographic region when compared to indicators of sediment contamination or eutrophication
36 (Nelson et al., 2004).
37 The extent of invasion was not uniform, however, among exposed and minimally exposed estuaries.
38 Estuaries with greater exposure to these invasion vectors were more invaded; 44 percent of the stations in
39 the exposed estuaries were moderately to highly invaded compared to only 21 percent of the stations in
40 minimally exposed estuaries (Exhibit 6-12). Nonetheless, the observation that 21 percent of the stations in
41 these "pristine" estuaries were at least moderately invaded indicates that non-indigenous species can
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Exhibit 6-12. Relative abundance of
non-indigenous benthic species in estuaries of
the Pacific Northwest, 1999-2001a
Extent of invasion:
Minimal"
Moderate'
High"
Percent of estuarine sites in each category:
All
estuaries
Exposed
estuaries*
Minimally
exposed
estuaries*
65.7
56.1
19.9
14.5
28.6
15.3
79.4
7.4
13.2
Study
area
Washington
Oregon
California
1 disperse widely once they are introduced into a region,
2 so even estuaries with no direct exposure to ballast
3 water or aquaculture are at risk of invasion.
4 Indicator Limitations
5 • This indicator presents baseline data only;
6 trend information is not yet available.
7 • Studies in the San Francisco Estuary (Lee
8 etal., 2003) and in Willapa Bay, WA
9 (Ferraro and Cole, in progress) have
10 shown that the percent of NIS can vary
11 substantially among communities so that
12 regional background values for the
13 Columbian Province as a whole may not
14 be appropriate for specific community
15 types.
16 « This indicator represents percent NIS in
17 individual benthic grabs of the soft-bottom
18 community, but does not characterize the
19 total number of NIS in the estuaries. It
20 also does not include fish or other taxa not
21 collected by benthic grabs.
22 • The data for the indicator were only
23 collected during the summer index period
24 and thus do not capture seasonal
25 variations.
26 « The threshold values for "minimal,"
27 "moderately invaded," and "highly
28 invaded" are preliminary and require
29 further research in order to establish their
30 ecological significance. Specific values
31 may differ in other biogeographic provinces.
32 Data Sources
33 Data for this indicator were collected by two different studies: EPA's National Coastal Assessment
34 (Coastal EMAP) and a special EPA study of minimally exposed estuaries. The complete results from
35 these studies were not publicly available at the time this report went to press, but summary data from the
36 1999 Coastal EMAP are available from Nelson et al. (2004; in review), and the underlying sampling data
37 from 1999 can be obtained from EPA's National Coastal Assessment database (U.S. EPA, 2005)
38 (http://www.epa.gov/emap/nca/html/data/index.html). Coastal EMAP sampling data and summary
39 statistics for 2000 and 2001 are expected to be made available in the near future. Results from the special
40 study of minimally exposed estuaries will also be published in the near future. Until then, data for this
41 indicator may be obtained from EPA's Western Ecology Division.
Coverage: Soft-bottom estuaries
between Cape Mendocino. CA, and
the Strait of Juan de Fuca, WA
(limited to sites with salinity >5
parts per thousand).
''Minimally invaded: 0-10%
of benthic organisms belong to
non-indigenous species
'Moderately invaded: >10-50% of
benthic organisms belong to non-
indigenous species
"Highly invaded: >50% of benthic organisms belong to
non-indigenous species
'"Exposed" estuaries are exposed to ballast water discharges from
international shipping and/or aquaculture of exotic oysters.
"Minimally exposed" estuaries are not.
Data source: U.S. EPA. 2005
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1 References
2 Lee II, H., B. Thompson, and S. Lowe. 2003. Estuarine and scalar patterns of invasion in the soft-bottom
3 benthic communities of the San Francisco Estuary. Biol. Invasions 5:85-102.
4 Lowe, S., M. Browne, S. Boudjelas and M. De Poorter. 2000. 100 of the world's worst invasive alien
5 species—a selection from the Global Invasive Species Database. Auckland, New Zealand: International
6 Union for the Conservation of Nature, Invasive Species Specialist Group.
7
8 Nelson, W.G., H. Lee II, and J. Lamberson. In review. Condition of estuaries of California for 1999: a
9 statistical summary. Washington, DC: U.S. Environmental Protection Agency.
10 Nelson, W.G., H. Lee II, J.O. Lamberson, V. Engle, L. Harwell, and L.M. Smith. 2004. Condition of
11 estuaries of the western United States for 1999: a statistical summary. EPA/620/R-04/200. Washington,
12 DC: Environmental Protection Agency.
13 Puget Sound Action Team. 2002. Puget Sound update: the eighth report of the Puget Sound Ambient
14 Monitoring Program (PSAMP). Olympia, WA: Puget Sound Water Quality Action Team.
15
16 U.S. EPA. 2005. National Coastal Assessment. Accessed 2005.
17
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1 6.3.3 Discussion
2 What These Indicators Say About Trends in the Diversity and Biological
3 Balance of the Nation's Ecological Systems
4 Few national programs track diversity and biological balance. However, there are ROE indicators
5 available for invertebrate communities and select vertebrates (birds and fish) and regionally for invasive
6 species (as these can be important disrupters of ecosystem balance) and important communities of
7 submerged aquatic vegetation. Some of these indicators show reduced or declining diversity for particular
8 groups of animals and plants, but this is not consistent across all the ROE indicators. The particular trends
9 of available ROE indicators are discussed below by plant and animal groupings, followed by the
10 limitations of the available information and future challenges.
11 Primary Producers
12 Primary producers range from the microscopic plants of the oceans to the giant redwoods of California.
13 The types of plants and the biomass they produce are fundamental to ecological systems. There have also
14 been well-documented, modest shifts in forest types and age classes in the past decade, as discussed in
15 Section 6.2.3.
16 Submerged aquatic vegetation (SAV) is an important biological component of aquatic systems,
17 contributing to diversity and balance by providing habitat and food. While there is no National Indicator
18 of trends in SAV, the Chesapeake Bay provides a regional example of a potentially wider-spread
19 phenomenon (see SAV in Chesapeake Bay indicator, p. 3-74). SAV has increased in the Bay over the past
20 25 years, but remains below its historic coverage, and the species composition also has changed
21 somewhat. Contributing factors in the Bay include excessive nutrients, sediment loads, diseases, and
22 physical disturbance.
23 Too much plant growth can shift the balance within aquatic ecosystems, and blooms of algae can sap
24 aquatic systems of necessary oxygen and even create toxic conditions. Blooms of toxic algae in the Gulf
25 of Mexico occur annually, but there have been fewer blooms in recent years as compared to 1996 (see
26 HAB Outbreaks in Western Florida indicator, p. 3-81). Such "red tides" occur along other coastal waters
27 and appear to be influenced by a combination of physical, chemical, and biological factors.
28 Invertebrates
29 Invertebrates such as worms, insects, and crustaceans are among the most diverse group of organisms.
30 Collectively they comprise the largest component of animal biomass on the planet and are critical
31 components of aquatic and terrestrial food webs. Trends in the composition of invertebrate communities
32 can reflect important environmental changes.
33 In the nation's coastal systems, baseline measures of invertebrate biodiversity and species composition
34 indicate that about one-fifth exhibit low biological condition (see Coastal Benthic Communities indicator,
35 p. 3-71). Because benthic invertebrates live on or in sediments, it is not surprising that most of these areas
36 also exhibit low sediment and/or water quality. For streams, the benthic macroinvertebrate Index of
37 Biological Integrity (IBI) exhibits a broad and even distribution from low to high values (see Benthic
38 Macroinvertebrates in Wadeable Streams indicator, p. 3-35). Exhibit 3-12 provides a basis for evaluating
39 future changes.
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1 Vertebrates
2 The biodiversity offish, amphibians, reptiles, birds, and mammals is influenced by available food
3 resources, the size and arrangement of suitable habitats, influxes of new species, climate and weather, and
4 the presence of contaminants. Vertebrates often receive much attention because they are highly visible
5 and are often near the top of the food chain.
6 Among vertebrates the most reliable indicator of national trends is for birds, which have been tracked
7 since 1966 (see Bird Populations indicator, p. 6-32). Bird populations are in dynamic flux. There appears
8 to be a net decline of populations most commonly found in the grassland and shrublands, comparable
9 increases and decreases in populations in woodlands, and some gains in populations inhabiting urban and
10 water/wetlands areas.
11 Fish are distributed throughout most of the nation's aquatic and marine ecological systems. Comparisons
12 between current and historic species compositions (see Fish Faunal Intactness indicator, p. 6-34) indicate
13 that one-fifth of the watersheds retain their full complement offish species, while about a quarter have
14 experienced of 10 percent or more loss in species. The losses occurred primarily in the Southwest and
15 Great Lakes.
16 Invasive Species
17 The infiltration of new species into areas is a natural phenomenon but can be accelerated through
18 intentional and unintentional introductions. Introduction of species such as kudzu, zebra mussels, grass
19 carp, starlings, and nutria have had profound effects on ecological systems.29 Many newly introduced
20 species may lack predators or parasites that kept these species under control in their native habitats,
21 allowing them to out compete resident species and even dominate entire systems. While national data are
22 lacking, the Non-Indigenous Estuarine Species in Pacific Northwest indicator (p. 6-37) shows that in the
23 Columbian Biogeographic Province (from California to Washington), about one-third of the stations
24 sampled were highly or moderately invaded with non-indigenous invertebrates.
25 Limitations, Gaps, and Challenges
26 A number of additional ROE indicators would help EPA better address the question of trends in diversity
27 and biological balance. While there are ROE indicators for the extent and distribution of vegetation types,
28 there remain gaps with respect to indicators of plant biodiversity in terrestrial and aquatic ecological
29 systems. There is no ROE indicator for threatened and endangered species. Also, there are no ROE
30 indicators for freshwater systems that are comparable to the coastal algal bloom indicator (e.g., for the
31 extent of nuisance aquatic plants such as the prolific growths of Eurasian milfoil and water chestnut in
32 lakes and ponds, which continue to create water management problems30'31). ROE Indicators of climate-
29 Lowe, S., M. Browne, S. Boudjelas, and M. De Poorter. 2000. 100 of the world's worst invasive alien species: a
selection from the Global Invasive Species Database. Auckland, New Zealand. World Conservation Union, Invasive
Species Specialist Group. 12 pp.
30 Madsen, J.D., J.W. Sutherland, J.A. Bloomfield, L.W. Eichler, and C.W. Boylen. 1991. The decline of native
vegetation under dense Eurasian water-milfoil canopies. J. Aquat. Plant Manage. 29:94-99.
31 Lake Champlain Basin Program, Federal Agencies Work Group. 2005. Opportunities for federal action: managing
aquatic non-native nuisance plants and animals,
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1 related vegetation changes also are lacking (e.g., fluctuations in the extent of kelp beds on the west coast
2 related to El Nino events32).
3 There are no ROE indicators for major groups of vertebrate biota including amphibians, reptiles, and
4 mammals. Because amphibians live both on land and in the water, their diversity and trends in their
5 abundance could be influenced by a wide range of stressors to air, water, and land. Recent reported
6 declines in amphibian populations worldwide indicate that losses are attributable in some areas primarily
7 to overharvesting, in others to loss of habitat, and in still others to unknown causes,33 but at this time there
8 is no National Indicator that meets the criteria for this report. There also are no ROE indicators for trends
9 in important insect or freshwater shellfish species.
10 Modern transportation and international trade in biota for food have caused invasive species to remain a
11 potentially important but poorly quantified source of stress to the diversity and balance of native species.
12 While the Non-Indigenous Estuarine Species in Pacific Northwest indicator (p. 6-37) provides some
13 insight into the potential importance of invasive species, the full significance of accelerated species
14 introductions is not captured by any ROE indicator.
15 In addition to indicator gaps and limitations, there are challenges to developing indicators of biological
16 diversity and balance even if the data were available. For example, establishing an appropriate time scale
17 for assessing trends in diversity and balance poses a major challenge. Biological variation is expected at
18 annual, decadal, and even longer time scales. Because of the limited time frames over which observations
19 have been made, parsing "normal" fluctuations in diversity and balance from longer-term trends is
20 difficult. Also the level of interest and care of observation can also change with time, confounding the
21 determination of actual trends.
22 Appropriate spatial scales are equally important. Regional Indicators provide helpful insights into
23 stressors affecting diversity and biological balance in some kinds of ecological systems for which there
24 are no National ROE Indicators. In fact, because many ecological systems vary so much by geographic
25 region, compilations of Regional Indicators may provide the only rational approach for identifying
26 meaningful trends. Especially important examples for biological diversity are unique ecosystems such as
27 the Arctic and Pacific islands. Trends in physical characteristics and processes can have far-reaching
28 effects. For example, polar bears represent important keystone species in the nation's arctic regions where
29 they are stressed by warming of coastal waters that limit the duration of ice formation and Pacific island
30 biota are stressed by invasive species and a number of other stressors.
31
32
32 Dayton, P.K., M. Tegner. 1984. Catastrophic storms, El Nino, and patch stability in a southern California kelp
community. Science 224(4646) :283-285.
33 Stuart, S.N., et al. 2004. A global census shows that most of the 5743 known amphibian species are in decline and
one-third are currently endangered. Science 306(5702): 1783-1786.
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1 6.4 WHAT ARE THE TRENDS IN THE ECOLOGICAL PROCESSES THAT
2 SUSTAIN THE NATION'S ECOLOGICAL SYSTEMS?
3 6.4.1 Introduction
4 Ecological systems are sustained by a number of biological processes that produce organic matter using
5 energy (photosynthesis and chemosynthesis), transfer carbon and nutrients (through food webs and
6 through decomposition), and enable the reproduction of organisms. Ecological systems are also shaped
7 and sustained by physical and chemical attributes and processes. These physical and chemical
8 components of ecological systems are considered in Section 6.5. Biological, physical, and chemical
9 processes collectively maintain ecological systems.
10 Ecological processes influence the extent, distribution, and biodiversity of systems. If primary production
11 declines, energy flow to higher trophic levels is diminished, potentially compromising the sustainability
12 of animal populations dependent on the plants for food. Primary production is influenced by the
13 availability of nutrients. Decreases and increases in nutrients can affect the amounts of primary
14 production as well as the types of plants with subsequent effects on animals. The successful reproduction
15 of plants and animals depends on the physical and chemical regimes of their environment.
16 Too much primary production can also cause problems, such as those that occur in eutrophic lakes that
17 experience an overload of nutrient inputs. Eutrophic conditions can alter the composition of the animal
18 and plant life and result in reduced oxygen levels due to decomposition of organic matter. For these
19 reasons, management of nutrient inputs is commonly driven by the potential for excessive plant growth.
20 Primary production and associated carbon cycling (which form the base of food webs), nitrogen cycling
21 (ammonification and nitrification), nutrient cycling (e.g., phosphorous and other essential elements for
22 sustainability of carbon-based life), and hydrogen/oxygen cycles (implicating hypoxic/anoxic conditions)
23 are fundamental ecological processes within systems. Processes related to the production, transfer, and
24 loss of biomass and the reproduction and death rates of individuals within populations are reflected in
25 various "end states" in time, snapshots of the outcomes of integrated processes. The standing stock of a
26 population or the amounts and types of carbon stored within an ecological system are measures of these
27 end states. While not processes themselves, trends in end states provide some insight into the relative
28 balance among processes. Carbon storage in forests, discussed in this section, is an example of such an
29 end state.
30 EPA has long been concerned with the impacts of human activities that can affect the rates, types, and
31 timing of ecological processes. In particular, activities that upset the balance between primary production
32 and respiration (e.g., biochemical oxygen demand, nutrients from fertilizers and human waste, and the
33 effects of UV-radiation) and activities that affect sediment erosion and transport are important factors in
34 water quality management. Many pesticides, chemicals used in industry, pollutants, and waste products
35 have the potential to interfere with species reproduction (one of the most important of ecological
36 processes). At local and regional scales, changes in land use that alter the extent and distribution of
37 ecological systems (Section 6.2) directly affect ecological processes within and adjacent to particular
38 areas. Concomitant changes often occur in primary production, nutrient cycling, and erosion and sediment
39 transport. For example, shifts from forested to urban or agricultural lands influence the amounts and types
40 of primary producers, the infiltration of water into soils, and the storage and cycling of carbon and
41 nutrients.
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1 6.4.2 ROE Indicators
2 This section examines trends in the ecological processes that sustain ecological systems for one National
3 Indicator (Table 6.4.1). Information for this indicator comes from satellite remote sensing, geographic
4 information systems, and independent field studies. Sources include the USDA Forest Service Forest
5 Inventory and Analysis (FIA). It is important to note that the data presented for carbon storage in forests
6 includes only forests classified as "timberland" which excludes about one-third of the forest land cover.
7 Timberland is defined as forests capable of producing at least 20 cubic feet per acre per year and not
8 withdrawn from timber utilization by regulation or statute. This is an important distinction between
9 previously illustrated trends in forest extent and type with the following discussion of carbon inventories.
10 Table 6.4.1. ROE Indicators of Trends in the Ecological Processes that Sustain the Nation's
11 Ecological Systems
12
NATIONAL INDICATORS
Carbon Storage in Forests
LOCATION
6.4.2 -p. 6-45
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INDICATOR: Carbon Storage in Fore
2 After carbon dioxide is converted into organic matter by photosynthesis, carbon is stored in forests for a
3 period of time in a variety of forms before it is ultimately returned to the atmosphere through the
4 respiration and decomposition of plants, animals, and the paper and wood products that result from tree
5 harvest. A substantial pool of carbon is stored in woody biomass (roots, trunks, and branches). Another
6 portion eventually ends up as organic matter in the upper soil horizons. Carbon storage in forest biomass
7 and forest soils is an essential physical and chemical attribute of stable forest ecosystems.
8 This indicator, developed by the USDA Forest Service (USDA Forest Service, 2004), tracks carbon
9 storage in the pools of living and dead biomass in forests in the contiguous 48 states. The carbon pools for
10 this indicator are estimated using USDA Forest Service Forest Inventory and Analysis (FIA) data from
11 five historical periods (circa 1953, 1963, 1977, 1987, and 1997). These data cover 37 states, mostly east
12 of the Mississippi, in the Rocky Mountains, or on the Pacific Coast (Smith et al., 2001, 2004). Alaska and
13 Hawaii are not included because of limited historical data. Carbon storage is estimated by the FIA
14 program using on-the-ground measurements of tree trunk size from many forest sites and statistical
15 models that show the relationship between trunk size and the weight of branches, leaves, coarse roots
16 (>0.1 inch in diameter), and forest floor litter combined with estimates of forest land area obtained from
17 aerial photographs and satellite imagery. These values are converted into carbon storages based on the
18 results of previous field studies (Smith and Heath, 2002; Smith et al., 2003; Birdsey, 1996). Forest floor
litter includes all dead organic matter above the
Exhib 16 13 Average annual net carbon
storage in forests of the contiguous U S , by
forest component, 1953 1996a
CD
sir
feS 150
je annual net
million metric
3 g
1
n
19531962 19631976 19771986
Reporting period
19871996
Coverage Forest land
classified as "timberland,"
which accounts for
approximately two thirds
of the forest land of the
contiguous 48 states
These data do not include
carbon stored in forest soil
Data source: USDA Forest
Service, Forest Inventory
and Analysis (FIA) Program
Aboveground live trees
Aboveground standing
dead trees
Understory vegetation
Down dead wood
(including stumps)
Forest floor litter
Belowground live trees (roots)
Belowground dead wood
mineral soil horizons, including litter, humus,
small twigs, and coarse woody debris (branches
and logs greater than 1.0 inches in diameter lying
on the forest floor). Organic carbon in soil is not
included.
What the Data Show
The change in carbon inventories from year to
year represents the net growth of trees minus the
amount of carbon removed in harvested timber.
The average rates of net carbon storage in forests
increased between the 1950s and the 1980s but
declined somewhat during the 1990s (Exhibit 6-
13). This trend varies among regions of the
country, but net storage has been positive in all
regions during the past two decades (Exhibit 6-
14).
The rate of storage for the last period of record
(1987-1996) decreased to 135 million metric tons
of carbon per year (MtC/yr), with declining
sequestration evident in live, dead, and understory
pools (Exhibit 6-13). This decline is thought to be
due to a combination of increased harvests relative
to growth, more accurate data, and better
accounting of emissions from dead wood (USDA
Forest Service, 2004). The rate of storage over this
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
18
19
20
21
22
23
24
25
26
27
28
29
30
31
period is equivalent to approximately
9 to 10 percent of the U.S. carbon
dioxide emissions over a comparable
period (U.S. EPA, 2005).
During the last period of record
(1987-1996), the North region
sequestered the greatest amount of
carbon, followed by the Rocky
Mountain region (Exhibit 6-14). The
trend of decreasing sequestration
between 1953 and 1996 in the South is
due to the increase in harvesting
relative to growth. Some of the
harvested carbon is sequestered in
wood products (USDA Forest Service,
2004).
17 Indicator Limitations
The data include only
forest classified as
"timberland," which
excludes about one-third
of U.S. forest land cover.
Historical data from
Alaska and Hawaii are
Exhibit 6-14. Average annual net carbon storage in forests of
the contiguous U.S. by region, 1953-1996a
100
& §
w >,
S £ 50
25
O) :=
£ E
-25
I,
1 1
• •
• North
• South
Rocky
Mountains
• Pacific
Coast
1953-1962
1963-1976
1977-1986
Reporting period
Coverage: Forest land classified as
"timberland," which accounts for
approximately two-thirds of the forest land
of the contiguous 48 states. These data do
not include carbon stored in forest soil.
Data source: USDA Forest Service, Forest
Inventory and Analysis (FIA) Program
1987-1996
Rocky
Mountains
Pacific
Coast
insufficient for inclusion in this indicator. Urban trees, agricultural soils, and yard trimming
are estimated by EPA to add about 15 percent to annual sequestration (U.S. EPA, 2005), but
these data are of much lower quality than the timberland data and are not included in the
indicator.
• Data are derived from state inventories that do not correspond exactly to the decades
identified in Exhibits 6-13 and 6-14.
• Carbon stored in forest soil is not included.
32
33
34
35
• Carbon pools are not measured, but are estimated based on inventory-to-carbon relationships
developed with information from ecological studies.
These limitations are discussed in detail in Smith and Heath (2000, 2001) and Heath and Smith (2000).
Data Sources
36 Exhibits 6-13 and 6-14 were previously published in the data supplement to USDA Forest Service (2004);
37 the numbers depicted in these figures have not been published, but were provided by the USDA Forest
38 Service. The raw measurements used as inputs in the carbon storage models can all be obtained from the
39 Forest Service's Forest Inventory and Analysis (FIA) database (USDA Forest Service, 2005)
40 (http://fia.fs.fed.us/tools-data/data/).
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1 References
2 Birdsey, R.A. 1996. Carbon storage for major forest types and regions in the conterminous United States.
3 In: Sampson, R.N., and D. Hair, eds. Forests and global change, volume 2: forest management
4 opportunities for mitigating carbon emissions. Washington, DC: American Forests, pp. 1-25, 261-308.
5 Heath, L.S., and J.E. Smith. 2000. An assessment of uncertainty in forest carbon budget projections.
6 Environ. Sci. Policy 3:73-82.
7 Smith, J.E., and L.S. Heath. 2000. Considerations for interpreting probabilistic estimates of uncertainty of
8 forest carbon. In: Joyce, L.A., and R. Birdsey, eds. The impact of climate change on America's forests.
9 General Technical Report RMRS-59. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research
10 Station, pp. 102-111.
11 Smith, J.E., and L.S. Heath. 2001. Identifying influences on model uncertainty: an application using a
12 forest carbon budget model. Environmental Management 27:253-267.
13 Smith, J.E., and L.S. Heath. 2002. Estimators of forest floor carbon for United States forests. Res. Pap.
14 NE-722. Newtown Square, PA: USDA Forest Service, Northeastern Research Station. 37 pp.
15 Smith, J.E., L.S. Heath, and P.B. Woodbury. 2004. How to estimate forest carbon for large areas from
16 inventory data. J. Forest. 102:25-31.
17 Smith, J.E., L.S. Heath, and J.C. Jenkins. 2003. Forest volume-to-biomass models and estimates of mass
18 for live and standing dead trees of U.S. forests. General Technical Report NE-298. Newtown Square, PA:
19 USDA Forest Service, Northeastern Research Station. 57 pp.
20 Smith, W.B., J.S. Vissage, D.R. Darr, and RM. Sheffield. 2001. Forest resources of the United States,
21 1997. General Technical Report NC-219. St. Paul, MN: USDA Forest Service, North Central Research
22 Station. 191 pp.
23 USDA Forest Service. 2004. National report on sustainable forests—2003. Washington, DC: USDA
24 Forest Service. (main site);
25 (data supplement: summary);
26 (data supplement: graphics
27 and metadata)
28 USDA Forest Service. 2005. Forest Inventory and Analysis (FIA) database. Accessed 2005.
29
30 U.S. EPA 2005. Inventory of U.S. greenhouse gas emissions and sinks: 1990-2003. EPA/43 O/R-05/003.
31 Washington, DC.
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1 6.4.3 Discussion
2 What This Indicator Says About Trends in the Ecological Processes that
3 Sustain the Nation's Ecological Systems
4 The ROE indicator provides data on trends in primary production and carbon cycles for terrestrial
5 systems. Primary producers capture, store, and supply solar derived energy to other species in the
6 system.34 In the forest, the energy currency is organic matter. Primary producers convert carbon dioxide
7 into organic matter, which is then available to species throughout the ecological system as an energy
8 resource and ultimately returns to the atmosphere (see Carbon Storage in Forests indicator, p. 6-45). For
9 forests, the stability of the system may depend on the balance between carbon stored in standing stock and
10 carbon lost from the system due to logging. Net carbon storage increased between 1950 and 1980,
11 followed by declines through the 1990s. The decline is thought to be due to external "technologies", i.e.
12 increased harvest, more accurate data, and improved dead wood assessment. During the 1987-1996 time
13 period, the greatest carbon storage occurred in the North and Rocky Mountain regions where there is
14 more tree growth (compared to harvesting), while the greatest decline in sequestration occurred in the
15 South where harvesting has been increasing relative to growth. The distribution of carbon has received
16 much attention not only from a biological point of view but also with respect to global cycles of carbon.
17 Increases and decreases in carbon storage suggest that other pools of carbon (e.g., within the aquatic and
18 atmospheric environments) are also changing. The distribution of carbon among all these pools reflects a
19 combination of processes and can also influence chemical, physical, and biological processes.
20 Limitations, Gaps, and Challenges
21 A major limitation of the indicator presented here is that it provides very little insight into ecological
22 processes across the nation. Indicators are lacking for primary production in aquatic systems, nutrient
23 cycling, secondary production, and reproduction and growth rates of populations. EPA recognizes this as
24 a gap in understanding trends in ecological processes. To some degree, information presented in Sections
25 6.2 and 6.3 gives insight into the net result of ecological processes. Trends in the extent and distribution
26 of ecological systems and in the biodiversity and balance of those systems reflect underlying processes
27 that produce food, cycle nutrients, and sustain populations of plants and animals. Sections 6.2 and 6.3 can
28 be thought of as addressing "end states" that indicate the results of underlying ecological processes.
29 Trends in these end states may or may not pick up important trends in the underlying processes because
30 systems are dynamic and internal relationships are rarely linear.
31 While the indicators of trends in ecological processes offer insights into potential threats to ecological
32 systems, they are also subject to limitations, including natural variability, application to narrow selection
33 of land uses (e.g., U.S. Forest Service timberland versus all forest lands protected and active,
34 grassland/shrubland waterways compared to forested or urban waterways), human-induced impacts, and
35 uncertainty about findings. Trends may be identified, but should be viewed within the context of the
36 indicator design.
34 Whitmarsh, I, and Govindjee. 1999. The photo synthetic process. In: Singhal, G.S., G. Renger, S.K. Sopory, K.-D.
Irrgang, and Govindjee, eds. Concepts in photobiology: photosynthesis and photomorphogenesis. New Delhi, India:
Narosa Publishers; Dordrecht, The Netherlands: Kluwer Academic Publishers, pp. 11-51.
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1 A limitation in the assessment of trends in carbon storage in forests is that the National Indicator captures
2 above-ground carbon and does not include a very important carbon storage medium (soil). In addition,
3 statistical models are employed to estimate carbon storage relationships between different tree
4 components. Carbon storage trends are important for assessing the future viability of ecological systems
5 and have increasing utility in evaluating global carbon cycles and potential climate change.
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1 6.5 WHAT ARE THE TRENDS IN THE CRITICAL PHYSICAL AND CHEMICAL
2 ATTRIBUTES AND PROCESSES OF THE NATION'S ECOLOGICAL
3 SYSTEMS?
4 6.5.1 Introduction
5 Numerous physical and chemical attributes and processes influence and sustain ecological systems.
6 Physical processes shape the physical conditions of ecological systems. Examples include soil generation,
7 erosion, sediment transport and deposition, changes in sea level, and physical disturbance regimes
8 involving periodic flooding and fires. Critical attributes are those that have shaped the evolutionary
9 history of species, govern the very nature of systems, and drive other processes. Critical physical
10 attributes include temperature, light, and hydrologic regimes (rainfall, soil moisture, flow rates). Critical
11 chemical attributes include oxygen, nutrients, pH, and salinity.35
12 Species have evolved within particular physical and chemical environments. These are characterized by
13 mean (i.e., long-term average) conditions as well as by fluctuations on time scales of a day (e.g., tidal and
14 light/dark cycles), seasons (e.g., temperature and hydrological cycles), years (e.g., periodic climatic and
15 fire events), and longer time scales. The occurrence of ice ages every 40,000 to 100,000 years reflects one
16 of the longer time scales. Because critical attributes and processes influence so many aspects of ecological
17 systems, small changes in average conditions or changes in temporal variations can potentially have large
18 effects on the extent and distribution of ecological systems and on the biodiversity of these systems.
19 Average conditions and the degree and periodicity of fluctuations vary over the surface of the globe, and
20 species have evolved with specific niche requirements that reflect the physical and chemical states of the
21 ecological systems in which they live. For this reason, a species that has evolved in tropical waters would
22 have temperature requirements that are higher and narrower (the species is less able to tolerate
23 fluctuations) than a species that has evolved in temperate waters where temperatures are lower and more
24 variable. Reproduction and other activity patterns of species are often related to physical and chemical
25 cues such as temperature, light, and salinity. Because species have evolved coincident with the presence
26 (or absence) of physical disturbances, reproductive strategies may be linked with the occurrence of events
27 which otherwise appear destructive. Thus, disturbances such as periodic fires or flooding may be essential
28 for sustaining certain species and ecological systems where these disturbances have been present over
29 evolutionary time scales.
30 Critical physical attributes and processes reflect, in part, the influence of solar radiation. Solar radiation
31 warms land and water masses and drives hydrologic cycles. The amount of light reaching the surface of
32 the earth and penetrating into its waters determines levels of photosynthesis which is essential to the
33 support of biological systems. Other examples of physical, chemical, and biological processes that are
34 influenced by the amount and periodicity of light include temperature and weather conditions,
35 photoactivation of chemicals, mutations, and the timing of reproductive cycles. Solar radiation can also
36 have potential harmful effects on some species. Light regimes can be influenced by changes in solar
37 energy reaching the earth, changes in the transparency of water, and changes in sea level and these change
35 Information on nutrients and potentially toxic chemicals is presented in Chapters 2, 3, and 4 of this report.
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1 the degree of light penetration reaching the sea floor, coral reefs, and kelp forests. The implication of
2 climate change for changes in many aspects of ecological condition has received broad attention.36
3 EPA has been actively involved over its three decades in assessing and managing factors that alter the
4 critical chemical and physical characteristics of ecological systems (e.g., temperature, pH,
5 electrochemical (redox) potential, and the transparency of air and water). For example, the use of water
6 for cooling purposes can result in temperature increases in receiving waters of a river, acid rain can lower
7 the pH levels of lakes in sensitive regions, and wastewater and fertilizer can lead to low redox potentials
8 which affect biological communities and the cycling of both toxic and non-toxic materials. Although EPA
9 is not directly involved in the control of hydrology, an important physical factor in the environment,
10 hydrology greatly influences the fate and transport of pollutants in aquatic ecosystems. Changes in the
11 amount of runoff can affect ground water levels as well as flows into streams and rivers. Flood control
12 efforts can alter flooding and sedimentation processes that sustain particular types of systems. Because
13 ground water is a primary source to surface water bodies in many parts of the nation, changes in the
14 quantity (water level) and quality of ground water influence ecological conditions not only in the
15 hyporheic zone (subsurface in sediments and soils) but also in surface waters. The potential impacts of
16 climate change (whether natural or human-induced) have important consequences for virtually every
17 aspect of ecological structure and function.
18 6.5.2 ROE Indicators
19 The evaluation of trends in the critical physical and chemical attributes of the nation's ecological systems
20 relies primarily on nine National Indicators and one Regional Indicator (Table 6.5.1). Information comes
21 from a variety of sources, including satellite remote sensing, geographic information systems, monitoring
22 programs, visual surveys, and independent field studies. Indicator data in this section are drawn from the
23 Heinz Center,37 National programs such as the USDA Forest Service Forest Inventory and Analysis (FIA)
24 program, EPA's Wadeable Streams Assessment (WSA), National Research Council,38 National
25 Atmospheric Deposition Program, National Aeronautics and Space Administration (NASA), National
26 Oceanic and Atmospheric Administration's (NOAA's) National Climate Data Center, U.S. Geological
27 Survey's National Water Quality Assessment Program, U.S. Geological Survey stream flow and water
28 quality monitors, and National Emissions Inventory.
36 Millennium Ecosystem Assessment Board. 2005. Living beyond our means: natural assets and human well being.
37 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. Forest pattern and
fragmentation. In: The state of the nation's ecosystems: measuring the lands, waters, and living resources of the
United States. New York, NY: Cambridge University Press, September 2002. Web update 2005.
38 National Research Council. 2001. Climate change science: an analysis of some key questions. Committee on the
Science of Climate Change. Washington, DC: National Academy Press.
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1 Table 6.5.1. ROE Indicators of Trends in the Critical Physical and Chemical Attributes of the
2 Nation's Ecological Systems.
NATIONAL INDICATORS
U.S. and Global Mean Temperature and Precipitation
Sea Surface Temperature
High and Low Stream Flows
Streambed Stability in Wadeable Streams
Sea Level
Nitrogen and Phosphorus Discharge from Large Rivers
Nitrogen and Phosphorus in Wadeable Streams
Nitrogen and Phosphorus in Streams in Agricultural Watersheds
Lake and Stream Acidity
REGIONAL INDICATORS
Extent of Hypoxia in the Gulf of Mexico and Long Island Sound
LOCATION
6.5.2 -p. 6-53
6.5.2 -p. 6-58
3.2.2 -p. 3-14
3.2.2 -p. 3-19
6.5.2 -p. 6-61
3.2.2 -p. 3-28
3.2.2 -p. 3-22
3.2.2 -p. 3-25
2.2.2 -p. 2-62
3.5.2 -p. 3-77
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INDICATOR: U.S. and Global Mean Temperature and Precipitation
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Air temperature and precipitation are two important properties of climate and are the most widely
measured variables. Changes in these indicators may have wide-ranging direct or indirect effects on
ecological condition and human health. These impacts may be positive or negative, depending on the
effect, the magnitude of change, and the location. For example, changes in temperature can affect heat
and cold-related mortality and illness due to altered frequency and magnitude of heat waves and cold
spells. Changes in temperature may also change the range and distribution of animal and plant species.
Precipitation changes affect water availability and quality which can have important effects on
agricultural, forest, animal, and fisheries productivity, as well as human nutrition. Indirect effects of
temperature and precipitation changes include changes in the potential transmission of vector-borne
infectious diseases. These may result from alterations in the ranges and seasons of animals that carry
disease or from accelerated maturation of certain
infectious parasites.
This indicator shows trends in temperature and
precipitation based on instrumental records from
1901 to 2005 (except for Alaska and Hawaii, where
records begin in 1918 and 1905, respectively). Air
temperature and precipitation trends are summarized
for the contiguous U.S., as well as for eleven climate
regions of the U.S., including Alaska and Hawaii
(these climate regions are different from the ten EPA
Regions). For context, this indicator also shows
trends in global temperature (over land and sea) and
global precipitation (over land) from 1901 to 2005.
Temperature and precipitation data are presented as
trends in anomalies. An anomaly represents the
difference between an observed value and the
corresponding value from a baseline period. This
indicator uses a 30-year baseline period of 1961 to
1990. To generate the temperature time series,
measurements were converted into monthly
anomalies, in degrees Fahrenheit. The monthly
anomalies then were averaged to get an annual
temperature anomaly for each year. Precipitation
trends were calculated in similar fashion, starting
with anomalies for total monthly precipitation, in
millimeters. Monthly anomalies were added to get.
annual anomaly for each year, which was then
converted to a percent anomaly—i.e., the percent
departure from the average annual precipitation
during the baseline period. Trends in temperature
and precipitation were calculated from the annual
time series by ordinary least-squares regression. For
each of the eleven climate regions, this indicator also
Exhibit 6-15. Annual temperature anomalies in
the contiguous U.S. and worldwide, 1901-20053
A. Contiguous U.S. temperature anomalies
JI.L.L
1901 -2005 trend: +1.09 T per century
1979-2005 trend: +5.63 T per century
1
0
-1
-2
-3
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
B. Global temperature anomalies
1901-2005 trend: +1.14 T per century
1979-2005 trend: +3.15 T per century
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
"Anomalies are calculated with respect to the 1961-1990 mean.
Data source: NOAA, National Climatic Data Center
45
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Exhibit 6-16. Annual temperature anomalies in the U.S. by region, 1901-2005
1901 -2005 trend: +1.69 F per century
1901-2005 trend:-0.04 F per century
1901-2005 trend:+0.16 F per century
E. East North Central
1901 -2005 trend: +0.04 T per century
1901 -2005 trend: +1.70 T per century
1901-2005 trend:+1.63 F per century
1901-2005 trend:+2.07 F per century
1901 -2005 trend: +1.70 F per century
1901 -2005 trend: +3.31 F per century
1901-2005 trend: +1.18 F per century
Anomalies are calculated with respect to the 1961-1990 mean.
^me series were smoothed using a 9-point binomial filter.
Data mine: NOM, National Climatic Data Center
Temperature change ( F per century):
No data 432101234
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1 shows a smoothed time series, which was created from the annual series using a nine-point binomial filter
2 (four years on each side, averaged with decreasing weights further from the center year).
3 What the Data Show
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Over the past century, temperatures rose across the
contiguous United States at an average rate of 0.11
°F per decade (1.1 °F per century) (Exhibit 6-15,
panel A). Average temperatures rose at an
increased rate of 0.56 °F per decade from 1979 to
the present. For reference, the most recent eight-
year (1998-2005), nine-year (1997-2005), and ten-
year (1996-2005) periods have been the warmest
on record for the United States (NOAA, in
progress). Warming occurred throughout the U.S.,
with all but three of the eleven climate regions
showing an increase of more than 1 °F since 1901
(Exhibit 6-16). The greatest temperature increase
occurred in Alaska (3.3 °F per century).
Trends in global temperature and precipitation
provide a context for interpreting trends in
temperature and precipitation in the U.S.
Instrumental records from land stations and ships
indicate that global mean surface temperature
warmed by about 1.1 °F during the 20th century
(Exhibit 6-15, panel B), similar to the rate of
warming within the contiguous U.S. From 1979 to
present, however, the U.S. warmed at nearly twice
the global rate.
Exhibit 6-17. Annual precipitation anomalies in
the contiguous U.S. and worldwide, 1901-2005*
20
15
, 10'
5
0
-5
-10
-15
-20
A. Contiguous U.S. precipitation anomalies
1901-2005 trend: +6.13% per century
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
20
15
, 10
5
0
-5
-10
-15
-20
B. Global precipitation anomalies
1901-2005 trend: +1.61% per century
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
Anomalies and percent change are calculated with respect to the
1961-1990 mean.
Data source: NOAA. National Climatic Data Center
As global mean temperatures have risen, global
mean precipitation also has increased (Exhibit 6-
17, panel B). This is expected because evaporation
increases with increasing temperature, and there
must be an increase in precipitation to balance the
enhanced evaporation (IPCC, 2001). Precipitation
over land increased by 1.6 percent globally since 1901, but the trends vary spatially and temporally. Over
the contiguous U.S., total annual precipitation increased at an average rate of 6.1 percent per century since
1901 (Exhibit 6-17, panel A), although there was considerable regional variability (Exhibit 6-18). The
greatest increases came in the East North Central climate region (11.6 percent per century) and the South
(11.1 percent). Hawaii was the only region to show a decrease (-9.25 percent).
39
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Exhibit 6-18. Annual precipitation anomalies in the U.S. by region, 1901-2005"
100
80
60
40
20
0
-20
-40
-60
A. Northeast
1901-2005 trend: +7.31 % per century
1900 1920 1940 1960 1980 2000
100
80
60
40
20
0
-20
-40
-60
D. South
1 901 -2005 trend: +1 1 .08% per century
1900 1920 1940 1960 1980 2000
G. Southwest
1901-2005 trend:+1.47% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
J. Alaska
1901-2005 trend: +6.08% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
100
80
60
40
20
0
-20
-40
-60
B. Southeast
1901-2005 trend: +2.96% per century
1900 1920 1940 1960 1980 2000
E. East North Central
1901-2005 trend: +11.55% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
100
80
60
40
20
0
-20
^0
-60
H. West
1901 -2005 trend:
+8.96% per century
1900 1920 1940 1960 1980 2000
K. Hawaii
1901-2005 trend: -9.25% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
Year
"Anomalies and percent change are calculated with respect to the
1961-1990 mean.
'time series were smoothed using a 9-point binomial filter.
Data mine: NOAA, National Climatic Data Center
C. Central
1901-2005 trend:+7.91% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
F. West North Central
1901-2005 trend: +2.96% per century
100
80
60
40
20
0
-20
-40
-60
1900 1920 1940 1960 1980 2000
100
80
60
40
20
0
-20
-40
-60
I. Northwest
1901-2005 trend: +5.45% per century
1900 1920 1940 1960 1980 2000
Northwest
West
North Central Central
East /
North Central /Northeast
Hawaii
Change In precipitation (% per century):
-30 -20 -10 0 10 20 30
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1 Indicator Limitations
2 • Biases may have occurred as a result of changes over time in instrumentation, measuring
3 procedures (e.g., time of day), and the exposure and location of the instruments. Where
4 possible, data have been adjusted to account for changes in these variables.
5 • Uncertainties in both the temperature and precipitation data increase as one goes back in time,
6 as there are fewer stations early in the record. However, these uncertainties are not sufficient
7 to mislead the user about fundamental trends in the data.
8 Data Sources
9 Data were provided by NOAA's National Climatic Data Center (NCDC), which calculated global, U.S.,
10 and regional temperature and precipitation time series based on monthly values from a network oflong-
11 term monitoring stations. Data from individual stations were obtained from the U.S. Historical Climate
12 Network (USHCN) and the Global Historical Climate Network (GHCN), which are NCDC's online
13 databases (NOAA, 2006).
14 References
15 IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: the scientific basis.
16 Contribution of Working Group I to: Houghton, J.T., Y. Ding, D.J. Griggs, M. Noguer, P.J. van der
17 Linden, X. Dai, K. Maskell, and C.A. Johnson, eds. Third assessment report of the Intergovernmental
18 Panel on Climate Change. Cambridge, United Kingdom, and New York, NY: Cambridge University
19 Press. 881pp.
20 NOAA (National Oceanic and Atmospheric Administration). 2006. National Climatic Data Center.
21 Accessed October 2006. (NCDC home page);
22 (U.S. Historical Climate Network);
23 (Global Historical Climate Network)
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INDICATOR: Sea Surface Temperatur
2 Sea surface temperature (SST) is a critical physical attribute of the oceans and coastal ecological systems.
3 Water temperature directly affects biological and physical process rates, water column stability, and the
4 presence and functioning of species of plants (e.g., algae, sea grasses, marsh plants, and mangroves) and
5 animals (e.g., microscopic animals, larger invertebrates, fish, and mammals). Increases in temperature
6 have been associated with the timing of breeding in sea turtles (Weishampel et al, 2004), stress and
7 bleaching of coral reefs (Brown, 1997; Woodbridge and Done, 2004), alteration of species migration
8 patterns, changes in ecological system extent and composition (Helmuth et al., 2002), and changes in the
9 frequency or extent of blooms of harmful algae (Ostrander et al., 2000). On longer time scales (decades to
10 centuries), rising SST may result in decreases in the supply of nutrients to surface waters from the deep
11 sea which could trigger a cascade of effects leading to decreases in primary production and declines in
12 fish production (Pratchett et al., 2004), wetland loss, reductions in coastal storm buffering, and losses of
13 local tourism. SST is both an indicator of, and a profound influence on, the climate system. Changes in
14 SST may result from long-term cycles in ocean circulation, climate variability, or secular trends in
15 climate (Committee on the Bering Sea Ecosystem et al., 1996).
16 This SST indicator, developed by the National Climate Data Center (NCDC) of the National Oceanic and
17 Atmospheric Administration (NOAA) and the National Center for Atmospheric Research (NCAR),
18 describes the long-term variability and change in global mean sea surface temperature for the period 1880
19 to 2005. This reconstruction provides consistent spatial and temporal data with their associated 95 percent
20 confidence intervals. The data are compiled from in-situ measurements from the International
21 Comprehensive Ocean-Atmosphere Data Set (ICOADS) release 2 (Slutz et al., 2002) and—in recent
22 years—from satellite imagery. Data are available from multiple sources (e.g., ship reports, buoy monitors,
23 oceanographic profiles) from as early as 1854 (Woodruff et al., 1998). By filtering and blending data sets
24 that use alternative measurement methods and include redundancies in space and time, this reconstruction
25 is able to fill spatial and temporal data gaps and correct for biases in the different measurement techniques
26 (e.g., uninsulated buckets, intakes near warm engines, uneven spatial coverage, etc.). The extended
27 reconstructed data are shown as anomalies, or differences, from the "normal" (i.e., average) SST from
28 1961 to 1990 (Smith and Reynolds, 1998). The long-term average change obtained by this method is very
29 similar to those of the "unanalyzed" measurements and reconstructions developed by other researchers
(e.g., Rayner et al., 2003).
Exh bit 6 19 Annual global sea surface temperature anomaly,
18802005"
08
-s 04
Upper 95% confidence interval
Annual
anomaly
Lower 95% confidence interval
1
•I
£. 04
^08
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
"Coverage Anomaly with respect to the 1961 1990 climate normal, which is plotted
as zero
Data source: NOAA, National Climatic Data Center
What the Data Show
The reconstruction of SST
anomalies over all latitudes
indicates that sea-surface
temperatures during the past
three decades are at their highest
levels over the period of record
(Exhibit 6-19). Warming has
occurred through most of the
twentieth century and appears to
be independent of measured
inter-decadal and short-term
variability (Smith and Reynolds,
2005). The SST warming occurs
in two parts, the first between
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1 1910 and 1940 and the second after 1970, with a roughly stationary period between 1940 and 1970. SST
2 appears to have cooled between 1880 and 1910, but confidence intervals are wide for the indicator over
3 the early period of record. Despite that uncertainty, warming for the entire period of the indicator and for
4 the period from 1900 forward is statistically significant.
5 Indicator Limitations
6 • The 95 percent confidence interval is wider than other methods for long-term reconstructions
7 and in mean SSTs this interval tends to dampen anomalies.
8 • The geographic resolution is coarse for ecosystem analyses but reflects long-term and global
9 changes as well as variability.
10 • The reconstruction methods used to create this indicator remove almost all random "noise" in
11 the data. However, the anomalies are also dampened when and where data are too sparse for a
12 reliable reconstruction. The 95 percent confidence interval reflects this "damping" effect as
13 well as uncertainty caused by possible biases in the observations.
14 • Data screening results in loss of many observations at latitudes higher than 60° N and 60° S.
15 Although the effects of screening at high latitudes on the indicator are extremely small on the
16 global average, its main effect is to lessen anomalies and widen the confidence intervals.
17 Data Sources
18 This extended reconstruction of SST, called ERSST.v2, was recently published in Smith and Reynolds
19 (2004). Data are available from NCAA's National Climate Data Center (NOAA, 2006b), which provides
20 access to monthly SST and error data from this reconstruction (ftp://ftp.ncdc.noaa.gov/pub/data/ersst-v2/)
21 as well as a mapping utility that allows the user to calculate average anomalies over time and space
22 (http://nomads.ncdc.noaa.gov/tfclimatencdc). Confidence intervals for the global average dataset were
23 provided by NOAA. The ERSST.v2 reconstruction is based on in-situ measurements and satellite data,
24 both of which are available from online databases. In-situ measurements are available from NOAA
25 (2006a) (http://icoads.noaa.gov/products.html), and satellite data from NASA (2006)
26 (http ://podaac .jpl .nasa.gov/sst/).
27 References
28 Brown, B. 1997. Coral bleaching: causes and consequences. Coral Reefs 16:8129-8138.
29 Committee on the Bering Sea Ecosystem, Polar Research Board, Commission on Geosciences,
30 Environment and Resources, and National Research Council. 1996. The Bering Sea ecosystem.
31 Washington, DC: National Academy Press, pp. 196-237.
32 Helmuth, B., C.D.G. Harley, P.M. Halpin, M. O'Donnell, G.E. Hermann, and C.A. Blanchette. 2002.
33 Climate change and latitudinal patterns of intertidal thermal stress. Science 298:1015-1017.
34 NASA. 2006. Physical Oceanography Distributed Active Archive Center (PO.DAAC), sea surface
35 temperature overview. NASA, Jet Propulsion Laboratory. Accessed 2006.
36
37 NOAA. 2006a. International Comprehensive Ocean-Atmosphere Data Sets (ICOADS). Accessed 2006.
38
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1 NOAA. 2006b. Sea surface temperature (SST) datasets. NOAA, National Climatic Data Center. Accessed
2 2006.
3 Ostrander, G.K., K.M. Armstrong, E.T. Knobbe, D. Gerace, E.P. Scully. 2000. Rapid transition in the
4 structure of a coral reef community: the effects of coral bleaching and physical disturbance. Proc. Natl.
5 Acad. Sci. USA 97(10):5297-5302.
6 Pratchett, M.S., S.K. Wilson, M.L. Berumen, and M.I. McCormick. 2004. Sublethal effects of coral
7 bleaching on an obligate coral feeding butterflyfish. Coral Reefs 23(3): 352-356.
8 Rayner, N.A., D.E. Parker, E.B. Horton, C.K. Folland, L.V. Alexander, D.P. Rowell, E.G. Kent, and A.
9 Kaplan. 2003. Global analyses of sea surface temperature, sea ice, and night marine air temperature since
10 the late nineteenth century. J. Geophys. Res. 108:4407. doi: 10.1029/2002JD002670.
11 Slutz, R.J., S.J. Lubker, J.D. Hiscox, S.D. Woodruff, R.L. Jenne, D.H. Joseph, P.M. Steurer, and J.D.
12 Elms. 2002. Comprehensive ocean-atmosphere data set; release 1. NTIS PB86-105723. Boulder, CO:
13 NOAA Environmental Research Laboratories, Climate Research Program. 268 pp.
14
15 Smith, T.M., and R.W. Reynolds. 1998. A high resolution global sea surface temperature climatology for
16 the 1961-90 base period. J. Climate 11:3320-3323.
17
18 Smith, T.M., and R.W. Reynolds. 2005. A global merged land air and sea surface temperature
19 reconstruction based on historical observations (1880-1997). J. Climate 18(12):2021-2036.
20
21 Smith, T.M., and R.W. Reynolds. 2004. Improved extended reconstruction of SST (1854-1997). J.
22 Climate 17:2466-2477.
23 Weishampel, J.F., D.A. Bagley, and L.M. Erhart. 2004. Earlier nesting by loggerhead sea turtles
24 following sea surface warming. Glob. Change Biol. 10:1.4. doi: 10.1111/j.l365-2486.2004.00817.x
25 Woodbridge, S., and T. Done. 2004. Learning to predict large-scale coral bleaching from past events: a
26 Bayesian approach using remotely sensed data, in-situ data, and environmental proxies. Coral Reefs
27 23(1):96-108.
28 Woodruff, S.D., H.F. Diaz, J.D. Elms, and S.J. Worley. 1998. COADS release 2 data and metadata
29 enhancements for improvements of marine surface flux fields. Phys. Chem. Earth 23(5-6):517-526.
30
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NDICATOR: Sea Le^
2 Sea level is an indicator of global and local change and a factor that affects human welfare and coastal
3 ecosystem conditions. Coastal areas host a rich set of natural and economic resources and include some of
4 the most developed and rapidly growing population centers in the nation. More than 100 million people
5 globally live within 1 meter of the mean sea level and more than 40 percent of the U.S. population lives in
6 watersheds along U.S. ocean coasts (NOAA, 2005). Changing sea levels can inundate low lying wetlands
7 and dry lands (Burkett et al, 2005), erode beaches (U.S. Geological Survey, 1998), change rates of
8 sedimentation (Olff et al., 1997), and increase the salinity of marshes, estuaries, and aquifers (Condrey et
9 al., 1995; Williams et al., 1999). Documented consequences of sea level rise include loss of buffering
10 against storms and floods (Burkett et al., 2005), changes in bird populations (Erwin, 2005) and land cover
11 (Williams et al., 1999), property losses (Burkett et al., 2005), and infrastructure damage (Theiler and
12 Hammar-Klose, 1999; U.S. Department of Transportation, 2003).
13 Approximately 58,000 km2 of land in the contiguous U.S. lie less than 1.5 m above sea level, 80 percent
14 of which is in Louisiana, Florida, Texas, and North Carolina (Titus and Richman, 2001). Almost half the
15 shoreline studied along the U.S. Atlantic Coast was determined to be highly to very highly vulnerable to
16 effects of sea level rise (Theiler and Hammar-Klose, 1999). The areas of highest vulnerability are high-
17 energy coastlines where the coastal slope is low and the major landform type is a barrier island. The risks
18 may be minimal if wetlands accretion can match or outpace sea level rises, but accretion rates vary widely
19 (Hartig et al., 2000, Table 3).
20 A number of factors affect sea level, including, but not limited to, changes in sea temperature, salinity,
21 and total water volume and mass (e.g. from melting glaciers or changes in the amount of water stored on
22 land). Sea level moves up with warming sea temperatures and down with cooling. Changes in the total
23 volume and mass of ocean water also result from the melting or accumulation of Antarctic and Greenland
24 ice sheets and non-polar glaciers and changes in the amount of water stored in lakes, rivers, and
25 groundwater. As such, global average sea level change is an indicator of the physical and climatic
26 stability of the global environment.
27 Temporal scale is an important factor in interpreting sea level trends. Sea level changes may reflect
28 factors such as seasonality, inter-annual to decadal scale variability such as "El Nino," and/or long-term
29 climate change (decades to centuries). Spatial scale also is important because absolute sea height does not
30 change uniformly around the globe.
31 This indicator presents trends in absolute and relative sea level. Absolute sea level represents only the sea
32 height, whereas relative sea level change is defined as sea height change plus land height changes (due to
33 subsidence or uplift and changes in natural land accretion). Relative sea level data are from the tidal
34 gauge measurements of the National Water Level Observation Network (NWLON) composed of
35 approximately 175 long-term, continuously operating stations located along the United States coast,
36 including the Great Lakes and along islands in the Atlantic and Pacific Oceans (Smith, 1980; Gill and
37 Schultz, 2001). Tidal gauge data are presented from 1950 to 1999, although a few locations have been
38 monitoring since the mid-1800s (NOAA, 2001). Absolute sea level data are from satellite measurements
39 from NASA's TOPEX/Poseidon spacecraft, which uses radar to map the precise features of the ocean
40 surface, and the "Jason" satellite which monitors ocean circulation (Leuliette et al., 2006). The two
41 satellites use radar altimetry to collect sea level data globally. These data have been available since 1993.
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Exhibit 6-20. Changes in relative sea level along U.S. coasts, 1950-1999'
75 N
15 N
"Trends are based on tidal gauge measurements. Each dot represents a tidal gauge
station that operated during the period 1950-1999,
Data source: NQAA, 2006
Mean relative sea level change (mm per year):
o -18 to-15 e -5.99to-3 o 3.01 to 6
o -14.99to-12 o -2.99toO o 6.01 to 9
• -11.9910-9 o0.01to3 e9.01to12
o -8.99to-6
2 What the Data Show
3 Relative sea levels (combined land and sea movement) in many locations rose from 1950 to 1999,
4 typically at rates of 0-3 millimeters per year (mm/yr) (up to one foot per century) (Exhibit 6-20). Relative
5 sea level has risen more rapidly (3-6 mm/yr) along the mid-Atlantic coast from North Carolina to New
6 Jersey and at rates as high as 9-12 mm/yr at two stations in Louisiana. Other locations, such as the
7 southern coast of Alaska, show relative sea level drop, with a maximum decrease of 16 mm/yr. Average
8 relative sea level rise for all U.S. coasts was not calculated because the distribution of tidal gauge stations
9 is not spatially representative of aggregate trends, but for reference, an analysis of tidal gauge data
10 worldwide estimated that on average, relative sea level rose between 1.5 and 2.0 mm/yr during the 20th
11 century (Miller and Douglas, 2004).
12 The satellite record shows that global mean absolute sea level (i.e., independent of land movements) has
13 increased at a rate of 3 mm (0.12 inches) per year since 1993 (Exhibit 6-21). Absolute sea levels do not
14 change uniformly around the Earth, however. Around the U.S., areas with increasing absolute sea level
15 include the Gulf coast and portions of the Atlantic coast (Exhibit 6-22). Areas showing a decrease include
16 the southern part of the Pacific coast and the western Gulf of Alaska.
17
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Exhibit 6-21, Global mean sea level, 1993-2006"
40
30
£f
E
S 20
cs
o
I 10
-10
-20
Trend: +3.0 mm per year
1992 1994 1996 1998 2000 2002 2004 2006
Year
Values are reported as anomalies with
respect to the 1993-1997 mean.
Data were collected by the
TOPEX/Poseidon and Jason 1 satellite
altimeters. Data were adjusted by
applying an inverse barometer (air
pressure) correction and removing seasonal signals.
Data source: Leuliette et al.. 2006
TOPEX measurements
° Jason measurements
— 60-day smoothing
Exhibit 6-22. Changes in absolute sea level along U.S. coasts, 1993-2006'
75'N-r
60'N -
15'N -
180
150"W
135'W
120V/
105W
'Trends are based on satellite measurements. Data were adjusted by
applying an inverse barometer (air pressure) correction.
Data source: Leutiette et al. 2006
90W 75'W 60'W
Mean absolute sea level change (mm per year):
No data -15 -10 -5 0 5 10 15
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1 Indicator Limitations
2 • An estimated 50 to 60 years of data are required to obtain linear mean sea level trends having
3 a 1 mm/yr precision with a 95 percent statistical confidence interval.
4 • Tidal gauge measurements do not represent more generalized (i.e. average) relative sea level
5 change along US coasts (or globally).
6 • Most local tidal gauge measurements cannot indicate whether changes in relative sea level are
7 due to changing water level or land level.
8 • Satellite data are not available for a multi-decadal time series needed to separate out medium-
9 term variability from long-term change.
10 • Satellite data are not horizontally precise enough to resolve sea level trends for small water
11 bodies (such as many estuaries) or for localized interests (such as a particular harbor or
12 beach).
13 Data Sources
14 Exhibit 6-20 is based on a map and corresponding trend data published by NOAA's National Oceans
15 Service (NOAA, 2006) (http ://tidesandcurrents .noaa.gov/sltrends/sltrends. shtml). These data also can be
16 found in NOAA (2001), along with a list of station coordinates (Appendix 1). Individual station
17 measurements are accessible through NOAA (2006).
18 Exhibits 6-21 and 6-22 were produced using data provided by Leuliette et al. (2006) (time series at
19 http://sealevel.colorado.edu/results.php; map at http://sealevel.colorado.edu/maps.php). Leuliette et al.'s
20 analysis was based on measurements from NASA's Ocean TOPography Experiment (TOPEX) and Jason
21 satellite altimeters; results were calibrated using a model documented in Leuliette et al. (2004). Satellite
22 measurements can be obtained from NASA's online database (NASA, 2006) (http://topex-
23 www.jpl .nasa. gov/science/data.html).
24 References
25 Burkett, V.R., D.B. Zilkoski, and D.A. Hart. 2005. Sea-level rise and subsidence: implications for
26 flooding in New Orleans, Louisiana. In: Subsidence observations based on traditional geodetic
27 techniques, and numerical models. U.S. Geological Survey, National Wetlands Research Center.
28
29 Condrey, R., P. Kemp, J. Visser, J. Gosselink, D. Lindstedt, E. Melancon, G. Peterson, and B. Thompson.
30 1995. Status, trends, and probable causes of change in living resources in the Barataria and Terrebonne
31 estuarine systems. Thibodaux, LA: Barataria-Terrebonne National Estuary Program.
32 Erwin, R.M. 2005. Atlantic sea level rise, lagoonal marsh loss, and wildlife habitat implications. U.S.
33 Geological Survey. Accessed December 29, 2005.
34
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1 Hartig, E.K., F. Mushacke, D. Fallen, and A. Kolker. 2000. A wetlands climate change impact assessment
2 for the metropolitan East Coast region. Draft for public review.
3
4 Leuliette, E.W., R.S. Nerem, G.T. Mitchum, and D.P. Chambers. 2006. Sea level change. Updated
5 October 2006 (2006 release #2).
6 Leuliette, E.W., R.S. Nerem, and G.T. Mitchum. 2004. Calibration of TOPEX/Poseidon and Jason
7 altimeter data to construct a continuous record of mean sea level change. Mar. Geod. 27(l-2):79-94.
8
9 Levermann, A., A. Griesel, M. Hoffmann, M. Montoya, and S. Ramstorf. 2005. Dynamic sea level
10 changes following changes in the thermohaline circulation. Clim. Dynam. 24:347-354.
11 Miller, L., and B.C. Douglas. 2004. Mass and volume contributions to twentieth-century global sea level
12 rise. Nature 428:406-409.
13 NASA (National Aeronautics and Space Administration). 2006. Ocean surface topography from space.
14 Updated January 2006.
15 NOAA (National Oceanic and Atmospheric Administration). 2006. Sea levels online. Accessed October
16 6, 2006. (home page);
17 (map);
18 (data table)
19 NOAA (National Oceanic and Atmospheric Administration). 2005. Population trends along the coastal
20 United States: 1980-2008.
21 NOAA (National Oceanic and Atmospheric Administration). 2001. Sea level variations of the United
22 States 1854-1999. NOAA Technical Report NOS CO-OPS 36.
23
24 Olff, H., J. De Leeuw, J.P. Bakker, R.J. Platerink, H.J. Van Wijnen, and W. De Munck. 1997. Vegetation
25 succession and herbivory in a salt marsh: changes induced by sea level rise and silt deposition along an
26 elevational gradient. J. Ecol. 85:799-814.
27 Smith, R.A. 1980. Golden Gate tidal measurements. J. Waterw. Port C. Div. 106(WW3):407-410.
28 Thieler, E.R., and E.S. Hammar-Klose. 1999. National assessment of coastal vulnerability to sea-level
29 rise: preliminary results for the U.S. Atlantic coast. U.S. Geological Survey Open-File Report 99-593.
30
31 Titus, J., and C. Richman. 2001. Maps of lands vulnerable to sea level rise: modeled elevations along the
32 U.S. Atlantic and Gulf coasts. Climate Res. 18:205-228.
33
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1 U.S. Department of Transportation. 2003. Does sea level rise matter to transportation along the Atlantic
2 coast? In: U.S. Department of Transportation, Center for Climate Change and Environmental Forecasting.
3 The potential impacts of climate change on transportation.
4
6 U.S. Geological Survey. 1998. The Chesapeake Bay: geologic product of rising sea level. Fact Sheet 102-
7 98.
8 Williams, K., K.C. Ewel, R.P. Stumpf, F.E. Putz, and T.W. Workman. 1999. Sea-level rise and coastal
9 forest retreat on the west coast of Florida, USA. Ecology 80(6):2045-2063.
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1 6.5.3 Discussion
2 What These Indicators Say About Trends in Critical Physical and Chemical
3 Attributes of the Nation's Ecological Systems
4 Critical Physical Attributes
5 Information is available on trends in temperature and precipitation (see Temperature and Precipitation
6 indicator, p. 6-53). Across the contiguous U.S., mean temperature increased over the past century. The
7 rate of increase in the past 30 years was higher than in the previous part of the century, amounting to
8 more than 0.5 °F per decade. Some regional trends in temperature are evident, with the southeastern
9 United States exhibiting some cooling and the western part of the country and Alaska exhibiting a greater
10 warming trend than the rest of the country.
11 These general warming trends have occurred concurrently with rising atmospheric concentrations of
12 greenhouse gases (see Greenhouse Gas Concentrations indicator, p. 2-100). The Intergovernmental Panel
13 on Climate Change concluded that "[tjhere is new and stronger evidence that most of the warming
14 observed over the last 50 years is attributable to human activities."39 The National Research Council
15 agreed that "[t]he changes observed over the last several decades are likely mostly due to human
16 activities," but cautioned that "we cannot rule out that some significant part of these changes is also a
17 reflection of natural variability."40
18 Virtually every ecological system in the United States is potentially vulnerable to changes in temperature
19 regimes that might affect either biological or physical conditions. These include coastal and marine
20 areas,41 inland freshwater and wetland systems,42 and terrestrial systems.43 The potential ecological
21 implications of a gradual warming trend have received much attention.44'45
39IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: the scientific basis.
Contribution of Working Group I to: Houghton, J.T., Y. Ding, D.J. Griggs, M. Noguer, PJ. van der Linden, X. Dai,
K. Maskell, and C.A. Johnson, eds. Third assessment report of the Intergovernmental Panel on Climate Change.
Cambridge, United Kingdom, and New York, NY: Cambridge University Press.
40 National Research Council. 2001. Climate change science: an analysis of some key questions. Committee on the
Science of Climate Change. Washington, DC: National Academy Press.
41 Kennedy, V.S., et al. 2002. Coastal and marine ecosystems and global climate change: potential effects on U.S.
resources. Arlington, VA: Pew Center on Global Climate Change.
42 Poff, N.L., M.M. Brinson and J.W. Day, Jr. 2002. Aquatic ecosystems and global climate change: potential
impacts on inland freshwater and coastal wetland ecosystems in the United States. Arlington, VA: Pew Center on
Global Climate Change.
43 Malcom, J., and L. Pitelka, 2000. Ecosystems and global climate change: a review of potential impacts on U.S.
terrestrial ecosystems and biodiversity. Washington, DC: Pew Center on Global Climate Change. 41 pp.
44 National Research Council. 2001. Climate change science: an analysis of some key questions. Committee on the
Science of Climate Change. Washington, DC: National Academy Press.
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1 Temperature changes can influence the physical aspects of ecological systems, including regional and
2 global weather and oceanographic patterns. Impacts associated with warming include the global retreat of
3 mountain glaciers, reduction in snow-cover extent, earlier spring melting of ice on rivers and lakes, and
4 increases in sea surface temperatures and ocean heat content.46 For example, sea surface temperature
5 increased throughout the past century, with the greatest increases occurring in the past three decades (see
6 Sea Surface Temperature indicator, p. 6-58). Changes in temperature also have shown variations
7 throughout the world's oceans.47'48
8 Temperature changes also can influence the biological aspects of ecological systems. All species have
9 preferred ranges of temperature for survival, growth, and reproduction as well as lower and upper thermal
10 tolerance limits. Mean temperature, seasonal changes, and other temporal fluctuations constitute species
11 temperature regimes. As these regimes change, several types of stresses are placed on species. The first is
12 that the species may not be as well adapted to the new regime and may not be able to sustain its
13 populations. The second is that other species may be better adapted and able to extend their ranges into
14 new areas. Finally, because temperature can affect other biological and physical attributes of systems, the
15 ecological system itself may change in a way that is not favorable for the species.
16 Temperature patterns are interlinked with air and water circulation patterns, which are critical to the
17 dispersal of organisms, the movement of nutrients, and many other processes important to sustaining
18 ecological systems. The replenishment of water over land surfaces is particularly critical, as it is a major
19 determinant of the sustainability of the varied ecological systems that exist along a gradient of moisture
20 from wetlands to deserts. For example, in areas where precipitation is reduced, droughts can have a
21 pronounced and rapid influence on vegetation.49
22 Overall, precipitation increased in the United States over the past century (see Temperature and
23 Precipitation indicator, p. 6-53). Regional differences are apparent, however, with the greatest increases in
24 the East North Central climate region and the South, very small increases in other regions, and a decrease
25 in Hawaii. It is difficult to assign causes to such local and regional changes in precipitation because of
26 natural climate variability (e.g., oscillations such as El Nino and others), complex interactions between
27 aerosols (from natural and industrial processes) and clouds, and the effects of urban and rural land use on
28 evaporation and transpiration.
45 Millennium Ecosystem Assessment Board. 2005. Living beyond our means: natural assets and human well being.
46 National Research Council. 2001. Climate change science: an analysis of some key questions. Committee on the
Science of Climate Change. Washington, DC: National Academy Press,
47 Barry, J.P., C.H. Baxter, R.D. Sagarin, and S.E. Oilman. 1995. Climate-related, long-term faunal changes in a
California rocky intertidal community. Science 267:672-675.
48 Levitus, S., J.I. Antonov, T.P. Boyer, and C. Stephens. 2000. Warming of the world ocean. Science 287:2225-
2229.
49 Allen, C., and D. Breshears. 1998. Drought-induced shift of a forest-woodland ecotone: rapid landscape response
to climate variation. PNAS 95(25): 14839-14842
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1 Physical Processes
2 Physical processes shape and sustain ecological systems. Stream flows carve and form aquatic habitats.
3 Whether moving sediment under high flow regimes or fostering sedimentation in lower flow regimes,
4 stream flow impacts ecological communities. The timing of seasonal flows coincides with the
5 reproductive cycles of some species. Trends revealing shifts in high and low flows and changes in no flow
6 periods forewarn of instability in ecological systems. Water cycles define habitat boundaries throughout
7 each year and across years. In some ecological systems streambeds may require an annual high flow event
8 to restore habitat that had been filled with debris and sediment during lower flow periods. The seasonal
9 trends are important for species depending on specific conditions (see Stream Flows indicator, p. 3-14).
10 Flow magnitude and timing and no-flow periods provide insights into trends in flow volumes that may
11 impact ecological processes, particularly the life cycles of species that depend on specific habitat
12 conditions.50 In one-half of the streams and rivers there have been shifts in magnitude of high or low
13 flows of up to 75 percent and timing shifts of up to 60 days. The trend has been an increasing change in
14 magnitude from the 1970s to the present.51 The number and duration of no-flow periods are decreasing.
15 Information on the stability of streambeds (see Streambed Stability indicator, p. 3-19) can be used as a
16 baseline against which future can be measured.
17 In many locations along the U.S. coast, sea level has steadily risen, reflecting changes in water levels as
18 well as subsidence in land in some areas (see Sea Level indicator, p. 6-61). These changes can alter the
19 ecological conditions in coastal areas, especially where land elevations are low. The rise of sea levels
20 results in increased flooding that can be exacerbated during storm events. Rising sea level also can result
21 in increased salinity levels in coastal inland waters and soils thereby changing the chemical environment
22 of habitats. Freshwater ecological systems are progressively lost as they are transformed into more saline
23 inland waters or into open coastal waters.
24 Critical Chemical Attributes
25 Dissolved oxygen is critical to the support of aerobic animals and plants. In aquatic systems, dissolved
26 oxygen levels reflect a balance between that produced by plants, consumption by all biota, and physical
27 mixing processes. The spatial extent and timing of reduced oxygen conditions (hypoxia) and no oxygen
28 conditions (anoxia) affects the distribution and sustainability of populations of aerobic organisms. As
29 hypoxic and anoxic areas increase in size and persistence, animals such as mollusks (snails and clams),
30 arthropods (e.g., crabs and shrimp), and fish have proportionally less habitat within which they can thrive.
31 For these reasons, trends in oxygen affects the sustainability of populations as well as the overall
32 biodiversity of aquatic and marine systems.
50 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. Forest pattern and
fragmentation. In: The state of the nation's ecosystems: measuring the lands, waters, and living resources of the
United States. New York, NY: Cambridge University Press, September 2002. Web update 2005.
51 The H. John Heinz III Center for Science, Economics, and the Environment. 2005. Forest pattern and
fragmentation. In: The state of the nation's ecosystems: measuring the lands, waters, and living resources of the
United States. New York, NY: Cambridge University Press, September 2002. Web update 2005.
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1 Regional information is available on baseline and trend hypoxic conditions in the Gulf of Mexico and
2 Long Island Sound (see Hypoxia in Gulf of Mexico and Long Island Sound indicator, p. 3-77). The size
3 of the hypoxic zones in both the Gulf of Mexico and Long Island Sound has been highly variable since
4 the mid-1980s, with no discernable trend in either area. In both cases, there remain substantial areas in the
5 latest year of record (2005) where low dissolved oxygen concentrations make the waters unsuitable to
6 support most fish and shellfish species.
7 Nutrient cycles are tightly interwoven into ecological processes. In stable, healthy ecological systems
8 these cycles supply the nutrients required to maintain and even expand populations. Aquatic systems,
9 receiving inputs throughout a watershed, are particularly susceptible to disrupted nutrient cycles. Nutrient
10 inputs within a watershed may impact ecological processes at a location far from the origin of the input
11 (e.g., input occurs upstream, but impact occurs at the mouth of a river). Indicators focusing on the most
12 active nutrients in aquatic systems- phosphorus and nitrogen- provide insights into trends in nutrient
13 loads, cycles, and transport.
14 Nutrient loads have been examined for the Mississippi, Columbia, St. Lawrence, and Susquehanna Rivers
15 (see N and P Discharge from Large Rivers indicator, p. 3-28). The largest of the monitored rivers, the
16 Mississippi River, contained more than 15 times the nitrate than the other rivers. The nutrient loads in this
17 river more than doubled from the 1950-1960s to the 1980-1990s. In contrast to the consistently upward
18 trend of nitrate discharge in the Mississippi River, the nitrate discharge in the Columbia River nearly
19 doubled in the 1990s compared to historic discharges, but returned to historic levels by 2002. Nitrate
20 levels increased in the St. Lawrence but did not exhibit a particular trend in the Susquehanna. Phosphorus
21 discharge trends are unclear in the Mississippi and Columbia Rivers and show a decrease in the St.
22 Lawrence and Susquehanna Rivers, likely due to phosphorus controls.
23 Baseline information for phosphorus and nitrogen is available for wadeable streams for the 1999 to 2004
24 period (see N and P in Wadeable Streams indicator, p. 3-22). The cumulative distributions exhibited
25 pronounced tails at the higher concentrations. The information indicates that for phosphorus 80 percent of
26 stream miles had concentration of 100 |o,g/L or less; the remaining 20 percent exhibited a broader range of
27 100 to about 900 |o,g/L. For nitrogen, 70 percent of the stream miles had nitrogen values of 1 mg/L or less;
28 the remaining 30 percent ranged from 1 to over 40 mg/L.
29 Agriculture-dominated watersheds are often characterized by higher loads of applied nitrogen and
30 phosphorus fertilizers to optimize crop development. Streams located within these areas provide an
31 indication of the extent of nutrient inputs. Baseline studies confirm that levels of nitrogen and phosphorus
32 are elevated in many of these water bodies (see N and P in Agricultural Streams indicator, p. 3-25).
33 The pH of air masses and waters is critical to biological functions, can directly affect the viability of
34 species, and can affect the bioavailability of chemicals (both nutrients and potential toxics). There has
35 been a decrease in wet deposition of sulfur and nitrogen compounds over the past 15 years, as discussed
36 in Chapter 2. Associated with the decrease in deposition has been an increase in the acid neutralizing
37 capability of water bodies (see Lake and Stream Acidity indicator, p. 2-62). Some sensitive regions—
38 New England and Blue Ridge—have not shown improvement from 1990 to 2000.
39 Limitations, Gaps, and Challenges
40 There are ROE indicators for only a few of the critical physical and chemical attributes and processes.
41 EPA would like to have ROE indicators for solar radiation over land and water as well as penetration into
42 the nation's waters. In addition, there are no ROE indicators of disturbance regimes associated with
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1 flooding and fire. Still, information is available for a few of the most critical attributes. Trends in
2 temperature provide insight into other trends that have important biological and physical ramifications.
3 The indicators of trends in chemical and physical life-sustaining parameters are influenced by uncertainty.
4 As technology changes, biases develop for data collected over long periods of time. Data collection tools
5 may improve, creating new uncertainties when comparing recent data to historic trend data. In historic
6 trend analyses, gaps in the record may emerge. Bridging the gaps between data series may require use of
7 estimation or interpolation methods, or those time periods may be excluded altogether. All indicators of
8 long-term trends are susceptible to changes in monitoring technology and historic data gaps. However, the
9 increase in temperature and precipitation is occurring and with the collection of additional data sets
10 longer-term trends can be confirmed or refuted.
11 Measuring trends in physical processes is subject to limitations. For the assessment of the indicator for
12 stream flow, establishing a baseline data set is challenging. In this case the baseline data do not represent
13 "natural" conditions because of the presence of dams and other human impacts on flow during the
14 baseline data years of 1930-1949. Also, the USGS gauging stations that generate the data for this
15 parameter are placed on the larger tributaries and may miss trends in the smaller waterways. However,
16 this indicator does provide valuable trend information regarding the general increase in high and low
17 flows for larger waterways. For the assessment of acidification, the focus is largely on areas where
18 previous studies revealed an impact. This may exclude areas that are impacted to a lesser extent by acid
19 rain.
20 While the large river surveys provide trend data for a watershed, it is not possible to identify the relative
21 contributions of different land uses in the river basin. More detailed studies focus on the most common
22 land use contributing to nutrient runoff. Each provides useful information regarding trends in the specific
23 system.
24 Information contained in the indicators represents baseline, decadal, and even century-level trends.
25 However, for hydrologic and temperature patterns, these time periods may be too short to assess long-
26 term changes. The field of paleoclimatology offers some promise for extending information to larger time
27 frames.52 In addition, the predictive capability of forecasting the extent of dissolved oxygen deficits in
28 regional and coastal water bodies is increasing.53 Information is also available on the distribution of solar
29 energy over the surface of the United States. Over time, such information could be used to evaluate trends
30 in this physical attribute.
31
52 National Oceanic and Atmospheric Administration. 2003. North American drought: a paleo perspective. April 22,
2003.
53 Longstaff, B.J., D. Jasinski, and P. Tango. 2005. Ecological forecast—summer 2005. Monitoring and Analysis
Subcommittee. Chesapeake Update.
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1 6.6 WHAT ARE THE TRENDS IN BIOMARKERS OF EXPOSURE TO COMMON
2 ENVIRONMENTAL POLLUTANTS IN PLANTS AND ANIMALS?
3 6.6.1 Introduction
4 Chemicals can be introduced to the environment intentionally (e.g., fertilizers, pesticides, and herbicides),
5 unintentionally, and through accidental spillage or leaks of chemicals used in home and commercial
6 applications (e.g., in wastes from municipal and industrial operations). The extent to which the presence
7 of mixtures of chemicals influences human health and the environment has long been a focus of EPA
8 assessments.
9 Biomarkers of exposure can include measures of chemical concentrations in plant and animal tissue. Such
10 measures provide insight into the magnitude of chemical exposure that organisms receive from their
11 environment. Measures of biological response such as biochemical concentrations (e.g., enzymes and
12 ligands) that respond to chemical exposures can also serve as biomarkers of exposure. Examples include
13 histopathological anomalies such as plant tissue damage from ozone or tumors in fish exposed to PAH-
14 contaminated sediment. This evaluation examines the trends in biomarkers of exposures to common
15 environmental pollutants in plants and animals based on the ROE indicators. It also discusses challenges
16 in assessing trends in these biomarkers.
17 Chemical stressors can have a detrimental effect on plant and animal communities. Chemical stressor
18 exposure to plant and animals can lead to increases in tissue concentrations of the chemical stressor in the
19 plants and animals. Once stressor concentrations are above threshold levels, they can affect physiological
20 systems within the plants and animals and can begin to have toxic effects on individuals within the
21 population. These individual effects can lead to changes in plant and animal community structure when
22 chemical stressor concentrations in the environment reach levels that can affect one or more species or
23 when the population numbers of a key species are detrimentally affected. Biomarkers of exposure,
24 including concentrations of chemical stressors or key biomarkers collected overtime within plants and
25 animals tissues, can help to gauge the health of a plant and animal communities over time. These
26 biomarkers of chemical exposure, when coupled with other information (e.g., toxicity testing results), can
27 provide a basis for estimating what levels of a chemical stress can and cannot be tolerated in the
28 environment by plant and animal communities. These biomarkers also help explain the recovery of
29 certain animal populations (e.g., Brown Pelican) that were once nearly driven to extinction by specific
30 chemical stressors. Tissue levels of pesticides, PCBs, and mercury have been used for many years to
31 evaluate exposures to such species as the Brown Pelican, Bald Eagle, and Lake Trout and a host of other
32 fish and wildlife. The Mussel Watch program relies on sampling lower trophic level organisms (mussels
33 and clams) for a broad range of chemicals to evaluate exposures in coastal areas. Therefore, measures of
34 bioaccumulative compounds in animal tissues provide an indication of exposure levels throughout food
35 webs.
36 6.6.2 ROE Indicators
37 Although trends in specific contaminants of concern in environmental media (e.g., sediments or air) have
38 been available for specific locations, the indicators to evaluate trends in biomarkers of exposure to
39 common environmental pollutants in plants and animals are mainly focused on national or regional
40 programs that have been measuring chemical stressor concentrations in fish tissue in lakes and coastal
41 regions of the United States over less than a decade. An example of such biomonitoring efforts is
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1 summarized in the National Coastal Condition Report II,54 which was completed as a collaborative effort
2 between EPA, NOAA, USFWS, and USGS.55
3 Trends in biomarkers of exposure to common environmental pollutants in plants and animals are
4 evaluated using three National Indicators (Table 6.6.1). The focus of this question is on national- or
5 regional-scale trends in biomarkers of exposure over the period that measurements have occurred (i.e., the
6 last one to three decades, depending upon the biomarkers of exposure). While other subregional or local-
7 scale efforts concerning monitoring of biomarkers of exposure cannot be covered here, they are no less
8 important.
9 Table 6.6.1. ROE Indicators of Trends in Biomarkers of Exposure to Common Environmental
10 Pollutants in Plants and Animals
NATIONAL INDICATORS
Coastal Fish Tissue Contaminants (N/R)
Contaminants in Lake Fish Tissue
Ozone Injury to Forest Plants
LOCATION
3.8.2 -p. 3-103
3. 8.2 -p. 3-107
2.2.2 -p. 2-37
11 N/R = National Indicator displayed at EPA Regional scale
12 6.6.3 Discussion
13 What These Indicators Say About Trends in Biomarkers of Exposure to
14 Common Environmental Pollutants in Plants and Animals
15 The ROE indicators provide a baseline of recent conditions against which future trends can be assessed.
16 Lipophilic chemicals such as PCBs, DDT, and methyl mercury are present in fish tissues throughout most
17 of the nation's freshwater lakes and coastal systems (Coastal Fish Tissue indicator, p. 3-103; Lake Fish
18 Tissue indicator, p. 3-107). This shows widespread exposure to these bioaccumulative compounds. Some
19 judgment concerning these levels can be made by reference to benchmarks that relate to tissue residues.
20 For example, contaminant levels in estuarine/marine fish were judged to be moderate with respect to
21 commonly used benchmarks. There are differences in exposure across EPA Regions. Six EPA Regions
22 exhibited what is considered to be poor conditions. The Southeast (Region 4) was the only Region with a
23 high (i.e., comparatively good) condition with respect to exposure levels of contaminants in fish. The
24 contaminants that were most responsible for varied conditions include polychlorinated biphenyls (PCBs),
25 mercury, and poly cyclic aromatic hydrocarbons (PAHs).
54 U.S. EPA. 2002. EMAP research strategy. EPA/620/R-02/002. Washington, DC.
55 Within USGS, the Biomonitoring of Environmental Status and Trends (BEST) Program under the National
Biological Service (NBS) is another example of a national program mandated to collect biomarkers of common
contaminant exposure. Although monitoring of fish contaminant concentrations is a focus of this program, this
program also monitors common pollutants in many other aquatic and terrestrial receptors, such as upper trophic
level receptors (fish-eating birds like the bald eagle), and catalogs biomarkers data collected from many sources into
an online database. [0]
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1 Foliar injury from ozone pollution disrupts plant/tree physiology. Baseline data indicate that exposure of
2 forests to ozone levels varies geographically (Ozone Injury to Forest Plants indicator, p. 2-37). Severe
3 injury from ozone was observed in 9 percent of southern sites, 8 percent of northern sites, 1 percent of
4 Pacific Coast sites, and no Rocky Mountain sites. Rocky Mountain and Pacific Coast sites had the least
5 overall foliar injury (with 0 percent in the Rocky Mountain sites).
6 Limitations, Gaps, and Challenges
1 Few national programs involve unbiased assessment that can support indicators of trends in national
8 conditions in biomarkers of exposure. While there are tissue-level ROE indicators for fish, there are no
9 similar indicators for plants (either aquatic or terrestrial) or wildlife species. This represents a gap in
10 EPA's ability to identify trends in biomarkers of exposure to common environmental pollutants in plants
11 and animals.
12 Some of the primary challenges that exist relating to monitoring biomarkers of exposure include the
13 following:
14 • To monitor a single biomarker of exposure on a national or regional scale requires a great
15 deal of planning, coordination, and resources. Biomarkers are more costly and time-
16 consuming to measure than chemical concentrations in other media (e.g., water, sediment,
17 air), because the living things that require measurement are more difficult to collect and/or
18 analyze for the chemical stressors.
19 • The biomarkers of exposure need to be clearly linked to biomarkers of effects to be useful for
20 predicting whether the function of plant or animal communities are being affected by the
21 concentrations of chemical in the environment. In many cases, capabilities are currently
22 lacking to link biomarkers of exposure with biomarkers of effects. In addition, most
23 monitoring focuses on the media within which plants and animal live (i.e., air and water), and
24 does not address the body burden of the chemical in the plant or animal or biomarkers of
25 effects.
26 • With a myriad of environmental contaminants in the environment, it is difficult to prioritize
27 which contaminants should be monitored in biological tissues. Classically, the organochlorine
28 pesticides (e.g., DDT), PCBs, and mercury have been monitored in fish tissues in the aquatic
29 environment. However, in the future, new chemicals may emerge as equally or more
30 important (see Afterword, Section 7.2).
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i 7. AFTERWORD
2 NEXT STEPS
3 EPA is committed to continually improving both the quality and quantity of information available to
4 answer important questions about the condition of air, water, land, human health, and ecological systems,
5 and how that condition is changing over time. The results of these improvements will be communicated to
6 the public via regular updates of EPA's Report on the Environment. Specific plans for updating the
7 Report include:
8 • EPA's 2007 ROE Science Report: Revised editions of this Science Report will be produced
9 every 3 years and timed to provide input to the Agency's strategic planning process. New editions
10 will reflect revisions or additions to the ROE questions, updates and revisions of the indicators in
11 this report, addition of new indicators, and revisions to the "Introduction" and "Discussion"
12 sections of the report.
13 • Electronic Report on the Environment (e-ROE): EPA's e-ROE, which provides users with the
14 ability to navigate and query the ROE content, will be updated on an ongoing basis to enable
15 users to obtain indicator revisions as soon as they are available.
16 • EPA ROE Highlights of National Trends 2007: This document, which communicates key
17 information in the Science Report to the interested public, will be updated periodically.
18 To strengthen its ability to answer the ROE questions, the Agency will work to improve current indicators
19 and add relevant new indicators that meet the ROE definition and criteria. EPA plans to:
20 • Expand its ability to present indicators and supporting data at variable geographical scales.
21 • Strengthen existing indicators, both by resolving their limitations and by filling specific spatial
22 and temporal gaps.
23 • Utilize improved research, science, and technology to develop new indicators.
24 • Work with the scientific community to ensure that the information reported meets EPA's high
25 standards for science.
26 Partnerships with federal, state, and non-government organizations to support indicator development and
27 improvement through coordinated research, monitoring, and data sharing will be critical to fulfilling this
28 commitment.
29 CHALLENGES
30 Throughout this report, EPA uses indicators to answer what it believes are among the most important
31 questions about the environment and human health. For many of these questions, the answers are
32 incomplete. Three important challenges affect EPA's ability to answer these questions:
33 • Gaps and limitations in ROE indicators.
34 • Emerging issues that suggest potential new areas of concern for which indicators are not yet
35 available.
36 • Difficulty in synthesizing and integrating information from multiple indicators to obtain a
37 coherent understanding of their interrelationships relevant to answering the ROE questions.
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1 All three areas offer opportunities for improvement in future editions of this report.
2 Indicator Gaps and Limitations
3 Each ROE question in this document focuses on a set of interrelated environmental issues (described in
4 the "Introduction" to the question) about which there is a good scientific understanding. In general, there
5 are ROE indicators that describe status and trends relating to some but not all of these issues. The
6 "Discussion" section for each question describes the limitations in the current indicators and their
7 underlying data, as well as gaps where no appropriate indicators are available to answer important parts of
8 the questions. EPA is working to strategically analyze gaps and limitations in order to identify priorities
9 for developing additional indicators and improving existing indicators for future reports.
10 Emerging Issues
11 In this report, "emerging issues" are issues whose potential to affect human health and the environment is
12 not well understood. Emerging issues pose different challenges to EPA's ability to answer the ROE
13 questions than do indicator gaps and limitations. For example, many emerging issues have only recently
14 been described in the scientific literature and popular press. Therefore, the current state of scientific
15 understanding makes it unclear whether indicators are needed, and if so, how they should be constructed
16 and tracked. Areas where issues potentially relevant to the ROE questions are emerging include:
17 • New technologies, contaminants, or environmental effects potentially related to such
18 contaminants. Examples include: brominated flame retardants;1'2 residues of pharmaceuticals
19 and personal care products;3'4> 5 air pollutants related to the use of alternative fuels (e.g., bio-
20 diesel);6 new chemicals and new uses for existing chemicals;7 wastes that contain multiple
1 Rayne, S., Ikonomou, M.G., and Antcliffe, B. 2003. "Rapidly increasing polybrominated diphenyl ether
concentrations in the Columbia River system from 1992 to 2000." Environmental Science and Technology 37(13):
2847-2854.
2 Birnbaum, L.S., and D.F. Staskal. 2004. Brominated Flame Retardants: Cause for Concern? Environmental Health
Perspectives 112(1): 9-17.
3 Daughton, C.G., and Ternes, T.A. 1999. Pharmaceuticals and Personal Care Products in the Environment: Agents
of Subtle Change? Environmental Health Perspectives 107(suppl 6): 907-944. Online at
http://www.epa.gov/nerlesdl/chemistry/ppcp/images/errata.pdf.
4 Koplin, D.W., E.T. Furlong, M.T. Meyer, E.M. Thurman, S.D. Zaugg, L.B. Barber, and H.T. Buxton. 2002.
Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: A national
reconnaissance. Environmental Science and Technology 36:1202-1211. Available at
http://pubs.acs.org/iournals/esthag/36/i06/pdf/esO 11055J .pdf
5 Lindsey, M.E., Meyer, M.T., and Thurman, E.M. 2001. Analysis of trace levels of sulfonamide and tetracycline
antimicrobials in groundwater and surface water using solid-phase extraction and liquid chromatography/mass
spectrometry. Analytical Chemistry 73(19): 4640-4646.
6 Morris, R.E., et al.. 2003. Impact of Biodiesel Fuels on Air Quality and Human Health. NREL/SR-540-33793.
Golden, CO: National Renewable Energy Laboratory, http://www.nrel.gov/docs/fy03osti/33793.pdf
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1 materials that are challenging to separate, particularly for recycling and reuse;8 the growing field
2 of nanotechnology and the potential release of engineered nanomaterials (e.g., nanoparticles) to
3 the environment;9 and diseases and conditions for which there is emerging evidence that exposure
4 to environmental contaminants may be a risk factor (see Section 5.3.3).
5
6 • Issues for which the inherent complexity of the interactions between pollutants,
7 environmental media, and ecological systems makes it unclear what should be measured.
8 Examples include: (1) interactions between changing climate and feedback mechanisms and the
9 effects of a wide range of pollutants on human health, water resources, ecosystems, coastal areas,
10 and other valued resources,10'11'12'13 including the distribution and occurrence of harmful algal
11 blooms or other pathogens;14 and (2) loss of genetic diversity, which may result in the loss of an
12 entire species if that species becomes less able to adapt to changing conditions.15
13
14 These examples are neither definitive nor prioritized, but offered simply to illustrate the types of
15 challenges that lie ahead.
16 Synthesis and Integration
17 Synthesizing and integrating information across multiple indicators has been a major challenge in
18 developing this report. Linkages between trends in different indicators have been noted where they are
7 U.S. DOE. 2000. Energy and Environmental Profile of the U.S. Chemical Industry Report prepared by Energetics
Incorporated. Columbia, MD http://www.eere.energy.gov/industry/chemicals/
8 U.S. EPA 2001. Electronics: A New Opportunity for Waste Prevention, Reuse, and Recycling United States Solid
Waste and EPA 530-F-01-006. Environmental Protection Emergency Response http://www.epa.gov/epr
9 Oberdorster, G., E. Oberdorster, and J. Oberdorster. 2005. Nanotoxicology: An emerging discipline evolving from
studies of ultrafine particles. Environ Health Perspect. 113:823-39.
10
Foley, J. 2005. Atmospheric Science: Tipping Points in the Tundra. Science 310(5,748):627-628.
11 Milkov, A.V. 2004. Global estimates of hydrate-bound gas in marine sediments: how much is really out there?
Earth Sci. Rev. 66(3-4): 183-197.
12 Faeth, P., and Greenhalgh, S. 2000. A Climate and Environmental Strategy for U.S. Agriculture. WRI Issue Brief,
World Resources Institute, Washington, DC, November 2000.
13 Harrison, J., and P. Matson. 2003. "Patterns and controls of nitrous oxide emissions from waters draining a
subtropical agricultural valley." Global Biogeochemical Cycles. 17(3): 1080.
14 Daniels, N.A., and Shafaie, A. 2000. A Review of Pathogenic Vibrio Infections for Clinicians. Infections in
Medicine 17(10): 665-685. Online at
http://www.issc.org/Vibrio vulnificus Education/Published%20Vibrio%20vulnificus%20Reference%20Materials.p
df.
15 Bagley, M. J., S. E. Franson, S. A. Christ, E. R. Waits, and G. P. Toth. 2003. Genetic Diversity As An Indicator
Of Ecosystem Condition And Sustainability: Utility For Regional Assessments Of Stream Condition In The Eastern
United States. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-03/056.
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1 clear and scientifically defensible (e.g., acid deposition and the acid neutralizing capacity in lakes and
2 streams, or air emissions and concentration of sulfur dioxide). However, in many cases, it is not clear
3 whether a trend in a human health or ecological indicator is directly linked to trends in other, potentially
4 related indicators. In developing future editions of the ROE, EPA will strive to identify approaches and
5 criteria for synthesis and integration that have a sound scientific basis.
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APPENDIX A:
GLOSSARY AND ACRONYMS
4 This glossary provides definitions for a limited set of terms. Most of these terms are included because
5 they have a particular usage or meaning either within EPA or in the context of this report. A few others
6 are included to ensure understanding of intended meaning because they are key terms within this report.
7 This glossary does not include other scientific terms for which standard definitions are readily available.
8 [Note: Acronyms will be added at a later stage.]
9 A
10 advisory: A nonregulatory document that communicates risk information to those who may have to make
11 risk management decisions. For example, a fish consumption advisory may recommend that people limit
12 or avoid eating certain species offish caught from certain lakes, rivers, or coastal waters. In some cases,
13 advisories may include recommendations for specific groups (such as infants, children, the elderly, or
14 women who are pregnant or may become pregnant).
15 agricultural and animal waste: Waste generated by the production and harvest of crops or trees or the
16 rearing of animals. Animal waste is a subset of agricultural waste and includes waste (e.g., feed waste,
17 bedding and litter, and feedlot and paddock runoff) from livestock, dairy, and other animal-related
18 agricultural and farming practices.
19 air pollutant: Any substance in air that could, in high enough concentration, harm humans, animals,
20 vegetation, or material. Air pollutants can include almost any natural or artificial composition of matter
21 capable of being airborne—solid particles, liquid droplets, gases, or a combination thereof. Air pollutants
22 are often grouped in categories for ease in classification; some of the categories are sulfur compounds,
23 volatile organic compounds, particulate matter, nitrogen compounds, and radioactive compounds
24 Air Quality Index (AQI): An index for reporting daily air quality that characterizes air pollution levels
25 and associated health effects that might be of concern. EPA calculates the AQI for five criteria pollutants.
26 AQI values range from 0 to 500; the higher the AQI value, the greater the level of air pollution and the
27 greater the health concern. AQI values below 100 are generally thought of as satisfactory. When AQI
28 values are above 100, air quality is considered to be unhealthy—at first for certain sensitive groups of
29 people, then for everyone as AQI values get higher. Refer to EPA's AIRNOW Web site
30 (http://www.epa.gov/airnow) for more information on the AQI and how it is calculated.
31 Air Quality System (AQS): EPA's electronic repository of ambient air monitoring data collected by
32 EPA, state, local, and tribal air pollution control agencies from thousands of monitoring stations. AQS
33 contains monitoring data, descriptive information about monitoring stations, and data quality assurance
34 and quality control information.
35 air toxics: Air pollutants that cause or may cause cancer or other serious health effects, such as
36 reproductive effects or birth defects, or adverse environmental and ecological effects. Examples of toxic
37 air pollutants include benzene, found in gasoline; perchloroethylene, emitted from some dry cleaning
38 facilities; and methylene chloride, used as a solvent by a number of industries. Air toxics are also known
39 as hazardous air pollutants.
40 anthropogenic: Originating from humans; not naturally occurring.
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1 area source: A source of air pollution that is released over an area that cannot be classified as a point
2 source. Area sources can include vehicles and other small engines, small businesses and household
3 activities, or biogenic sources such as a forest that releases hydrocarbons.
4 B
5 baseline: A reference condition against which changes or trends are judged—usually a set of conditions
6 that exist at a particular point in time.
7 benchmark: A concentration or other accepted measure against which environmental conditions are
8 compared.
9 bioaccumulative compound: A compound that tends to accumulate in tissues and build up in food webs.
10 Some bioaccumulative compounds can potentially have adverse effects on ecosystems or human health.
11 biogenic source: An air emissions source created by some sort of biological activity. Examples include
12 emissions resulting from microbial activity in soils and emissions from trees and other vegetation.
13 Emissions from biogenic sources are a subset of emissions from natural sources (see natural source).
14 biological balance: The interrelationships among organisms, including the structure of food webs and the
15 ability of ecological systems to maintain themselves over time. Balance is a dynamic characteristic, rather
16 than a fixed state.
17 biological diversity: The variety and variability among living organisms and the ecological complexes in
18 which they occur. Though it most often refers to the numbers of species, the term can apply to levels of
19 organization ranging from genes to ecoystems.
20 biomarker: A molecular or cellular indicator (or "marker") of an event or condition (exposure, effect,
21 susceptibility) in a biological system or sample. The product of an interaction between a contaminant and
22 some target molecule or cell.
23 biomarker of effect: A measure of disease progression, representing a measurable alteration at the
24 molecular, cellular, or some other structural level in the body that can be recognized as a potential or
25 established adverse health effect. Such a biomarker can indicate a biological response or health effect
26 related to a chemical or other stressor; however, it is not always possible to link a biomarker with
27 exposure to a single substance.
28 biomarker of exposure: The level of a contaminant or its metabolite collected from the body or from
29 substances produced or excreted within biological systems. In humans, this measurement can reflect the
30 amount of the contaminant that is stored in the body, and is sometimes referred to as the body burden. It
31 indicates the level of exposure.
32 biomarker of susceptibility: A measurement of individual factors that can affect response to
33 environmental agents. Examples include enzymes whose presence or absence may reflect a particular
34 genetic condition.
35 biomonitoring: The measurement of human tissues or excreta from biological systems for direct or
36 indirect evidence of exposure to chemical, biological, or radiological substances.
37 biotic environment: The biological component of an ecosystem, including plants and animals.
38
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1 C
2 cleanup: Action taken to deal with a release (or threat of release) of a hazardous substance that could
3 affect humans and/or the environment. This term is sometimes used interchangeably with the terms
4 "remedial action," "removal action," "response action," and "corrective action."
5 climate change: A term sometimes used to refer to all forms of climatic inconsistency; because the
6 Earth's climate is never static, the term is more properly used to imply a significant change from one
7 climatic condition to another. In some cases, "climate change" has been used synonymously with "global
8 warming." Scientists, however, tend to use "climate change" in the wider sense to also include natural
9 changes in climate.
10 coastal waters: Waters at the interface between terrestrial environments and the open ocean. Many
11 unique habitats lie in coastal waters—for example, estuaries, coastal wetlands, seagrass meadows, coral
12 reefs, mangrove and kelp forests, and upwelling areas.
13 community: In ecology, an assemblage of populations of different species within a specified location in
14 space and time. Sometimes, a particular subgrouping may be specified, such as the fish community in a
15 lake or the soil arthropod community in a forest.
16 community water system: A water system that supplies drinking water to 25 or more of the same people
17 year-round in their residences.
18 condition: The state of a resource, generally reflecting a combination of physical, chemical, and
19 biological characteristics such as temperature, water clarity, chemical composition, or the status of
20 biological communities. ROE questions address the condition of fresh surface waters, ground water,
21 wetlands, coastal waters, recreational waters, and consumable fish and shellfish. (Also see ecological
22 condition)
23 construction and demolition debris: Waste materials generated during the construction, renovation, and
24 demolition of buildings, roads, and bridges. Construction and demolition debris often contains bulky,
25 heavy materials such as concrete, wood (from buildings), asphalt (from roads and roofing shingles),
26 gypsum (from drywall), metals, bricks, glass, plastics, building components (doors, windows, plumbing
27 fixtures), and trees, stumps, earth, and rock from clearing sites.
28 contaminant: Any physical, chemical, biological, or radiological substance or matter that has an adverse
29 effect on air, water, or soil.
30 contaminated land: Land that has been polluted with hazardous materials and requires cleanup or
31 remediation. Contaminated lands include sites contaminated as a result of improper handling or disposal
32 of toxic and hazardous wastes, sites where improper handling or accidents released toxic or hazardous
33 materials that are not wastes, and sites where toxics may have been deposited by wind or flooding.
34 criteria pollutants: A group of six widespread and common air pollutants that EPA regulates on the
3 5 basis of standards set to protect public health or the environment (see National Ambient Air Quality
36 Standards). The six criteria pollutants are carbon monoxide, lead, nitrogen dioxide, ozone, particulate
37 matter, and sulfur dioxide.
38
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1 D
2 deleted NPL site: A site that has been deleted from the Superfund National Priorities List because its
3 cleanup goals have been met and there is no further need for federal action. See Superfund and 'National
4 Priorities List.
5 drinking water quality: Refers to whether contaminants are present in water that people drink—
6 including water from the tap, private wells, hauled water, untreated surface water sources, and bottled
7 water—at levels that could affect human health.
8 drinking water standards: Regulations that EPA sets to control the level of contaminants in the nation's
9 drinking water. Enforceable standards include Maximum Contaminant Levels (MCLs) and Treatment
10 Techniques (TTs) (see separate entries for each). Drinking water standards apply to all public water
11 systems (see public water system).
12
13 E
14 ecological condition: A term referring to the state of the physical, chemical, and biological characteristics
15 of the environment, and the processes and interactions that connect them.
16 ecological connectivity: A term referring to the connected system of open space throughout an ecosystem
17 and adjacent ecosystems. Includes the presence of ecotones, the transitional regions between ecosystems.
18 ecological processes: The metabolic functions of ecosystems—energy flow, elemental cycling, and the
19 production, consumption, and decomposition of organic matter.
20 ecological system: A hierarchically nested area that includes all living organisms (people, plants,
21 animals, and microorganisms), their physical surroundings (such as soil, water, and air), and the natural
22 cycles that sustain them.
23 ecoregion: An area within which the ecosystems—and the type, quality, and quantity of environmental
24 resources—are generally similar. An ecoregion can serve as a spatial framework for the research,
25 assessment, management, and monitoring of ecosystems and ecosystem components. Several different
26 classification schemes have been developed, at various resolutions. For more information about EPA's
27 ecoregion designations for North America, visit
28 http://www.epa.gov/wed/pages/ecoregions/ecoregions.htm.
29 ecosystem: The interacting system of a particular biological community and its non-living environmental
30 surroundings, or a class of such systems (e.g., forests or wetlands).
31 emission factor: The relationship between the amount of pollution produced by a particular source and
32 the amount of raw material processed. For example, an emission factor for a blast furnace making iron
33 might be pounds of particulates emitted per ton of raw materials processed.
34 emission inventory: A listing, by source and pollutant, of the amount of air pollutants discharged into the
35 atmosphere. Emission inventories can be based on emissions estimates, emissions measurements, or both.
36 end state: Any one of a number of ecosystem characteristics observed at a point in time. The term is
37 commonly used to represent the results of ecological processes.
38 endpoint: A biological or ecological characteristic that is the basis for evaluation or measurement.
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1 EPA Region: One often EPA geographic divisions, each responsible for executing the Agency's
2 programs within a specific group of states and territories. A map of the EPA Regions is provided in
3 Figure 1-1.
4 ephemeral waters: Waterbodies (e.g., streams or wetlands) that contain water for brief periods, usually
5 in direct response to a precipitation event. Ephemeral waters generally flow for a shorter time period than
6 intermittent waters, although in some cases the terms are used interchangeably (see intermittent waters).
1 exposure: For humans, the amount of a chemical, physical, or biological contaminant at the outer
8 boundary of the body available for exchange or intake via inhalation, ingestion, or skin or eye contact.
9 extent: The amount and distribution of a resource, which may be measured in terms of spatial area,
10 volume, depth, or flow (e.g., for water resources). ROE questions address the extent of fresh surface
11 waters, ground water, wetlands, and coastal waters.
12 extraction and mining waste: Soil and rock generated during the process of gaining access to the ore or
13 mineral body, as well as water that infiltrates the mine during the extraction process. This category also
14 includes certain wastes associated with the beneficiation of ores and minerals, including wastes from the
15 following activities: crushing, grinding, washing, dissolution, crystallization, filtration, sorting, sizing,
16 drying, sintering, pelletizing, briquetting, calcining to remove water and/or carbon dioxide, roasting in
17 preparation for leaching (except where the roasting/leaching sequence produces a final or intermediate
18 product that does not undergo further beneficiation or processing), gravity concentration, magnetic
19 separation, electrostatic separation, floatation, ion exchange, solvent extraction, electrowinning,
20 precipitation, amalgamation, and heap, dump, vat, tank, and in situ leaching.
21
22 F
23 final NPL site: A site that has been formally added to the Superfund National Priorities List. See
24 Superfund and National Priorities List.
25 finished water: Water that has been treated and is ready to be delivered to customers.
26 fossil fuel combustion waste: Waste from the combustion of oil, natural gas, or petroleum coke; the
27 combustion of coal at electric utilities and independent power-producing facilities, non-utilities, and
28 facilities with fluidized bed combustion technology; or the combustion of mixtures of coal and other fuels
29 (i.e., coburning of coal with other fuels where coal is at least 50 percent of the total fuel.
30
31 G
32 global climate change: See climate change.
33 greenhouse gas: Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include
34 water vapor, carbon dioxide (CO2), methane (CFL,), nitrous oxide (N2O), halogenated fluorocarbons
35 (HCFCs), ozone (O3), perfluorinated carbons (PFCs), and hydrofluorocarbons (HFCs).
36
37 H
38 hazardous air pollutants: See air toxics.
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1 hazardous waste: Waste with properties that make it dangerous or potentially harmful to human health
2 or the environment. The universe of hazardous wastes is large and diverse. Hazardous wastes can be
3 liquids, solids, contained gases, or sludges. They can be the by-products of manufacturing processes or
4 simply discarded commercial products, like cleaning fluids or pesticides. Hazardous waste is regulated
5 under the Resource Conservation and Recovery Act (RCRA) Subtitle C (see RCRA hazardous waste for
6 the regulatory definition). States can identify additional wastes as hazardous beyond those identified by
7 EPA.
8 health-based standards: Standards based on an evaluation of available data on existing or potential risks
9 to human health.
10 high-priority Corrective Action site: One of 1,714 RCRA Corrective Action Program Cleanup Baseline
11 sites, designated in 1999 as having high priority for cleanup by federal and state agencies. See RCRA
12 Cleanup Baseline.
13 hypoxia: The occurrence of low dissolved oxygen concentrations in water. Hypoxia is generally defined
14 with respect to saturation; because saturation levels vary with temperature and salinity, the concentration
15 that defines hypoxia may vary seasonally and geographically. In practice, scientists often use a threshold
16 of 2 parts per million, the generally accepted minimum required for most marine life to survive and
17 reproduce.
18
19 I
20 impervious surface: A hard surface area that either prevents or retards the entry of water into the soil
21 mantle or causes water to run off the surface in greater quantities or at an increased rate of flow. Common
22 impervious surfaces include rooftops, walkways, patios, driveways, parking lots, storage areas, concrete
23 or asphalt paving, and gravel roads.
24 index: A single number, derived from two or more environmental variables, that is intended to simplify
25 complex information. For example, the Index of Biological Integrity combines several metrics of benthic
26 community condition into a single index score.
27 index period: In EPA's aquatic resource monitoring, a term used to describe the portion of the year when
28 data are collected. The index period is often selected based on ecological considerations.
29 indicator: A numerical value derived from actual measurements of a stressor, state or ambient condition,
30 exposure, or human health or ecological condition over a specified geographic domain, whose trends over
31 time represent or draw attention to underlying trends in the condition of the environment.
32 industrial non-hazardous waste: Waste generated from processes associated with the production of
33 goods and products, such as electric power generation and manufacturing of materials such as pulp and
34 paper, iron and steel, glass, and concrete. This waste usually is not classified as municipal solid waste by
35 the federal government, but some states may classify it as such if it enters the municipal solid waste
36 stream.
37 industrial source: A term used in this report to describe air emissions sources of industrial origin. The
38 report breaks industrial sources down into contributions from selected industries, as appropriate.
39 intermittent waters: Waterbodies (e.g., streams or wetlands) that contain water for part of each year, due
40 to precipitation events and some ground water contributions. Intermittent streams and wetlands typically
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1 contain water for weeks or months, while "ephemeral" streams and wetlands contain water for briefer
2 periods—but in some cases these terms are used interchangeably (see ephemeral waters).
3 invasive species: A non-indigenous plant or animal species that can harm the environment, human health,
4 or the economy.
5
6 L
7 land treatment unit: A site where physical, chemical, and biological processes occurring in the topsoil
8 layers (e.g., naturally occurring soil microbes and sunlight) are used to treat and contain waste. Hazardous
9 waste is applied directly to the soil surface or incorporated into the upper layers of the soil, where its
10 constituents are degraded, transformed, or immobilized. Liner systems or leachate collection and removal
11 systems are not required for land treatment units. Closure consists primarily of placing a vegetative cover
12 over the unit and certifying that hazardous constituent levels in the treatment zone do not exceed
13 background levels.
14 landfill: A disposal site for solid wastes spread in layers, compacted to the smallest practical volume, and
15 covered by material (e.g., soil). Landfills are designed to isolate waste from the surrounding environment
16 (e.g., ground water, rain, air). Landfills are subject to requirements that include installing and maintaining
17 a final cover, operating leachate collection and removal systems, maintaining and monitoring the leak
18 detection system, ground water monitoring, preventing storm water run-on and -off, and installing and
19 protecting surveyed benchmarks.
20
21 M
22 Maximum Contaminant Level (MCL): The highest level of a contaminant that EPA allows in drinking
23 water. MCLs are enforceable standards that ensure that drinking water does not pose either a short-term
24 or long-term health risk. EPA sets MCLs at levels that are economically and technologically feasible.
25 Some states set MCLs that are more strict than EPA's.
26 medical waste: Any solid waste generated in the diagnosis, treatment, or immunization of human beings
27 or animals, in research pertaining thereto, or in the production or testing of biologicals, excluding
28 hazardous waste identified or listed under 40 CFR Part 261 or any household waste as defined in 40 CFR
29 Sub-Section 261.4(b)(l).
30 metal mining sector: Metal mining facilities that fall within Standard Industrial Classification Code 10
31 and must report to the Toxics Release Inventory in accordance with Section 313 of the Emergency
32 Planning and Community Right to Know Act.
33 mobile source: A term used to describe a wide variety of vehicles, engines, and equipment that generate
34 air pollution and that move, or can be moved, from place to place. "On-road" sources are vehicles used on
35 roads to transport passengers or freight. "Nonroad" sources include vehicles, engines, and equipment used
36 for construction, agriculture, transportation, recreation, and many other purposes.
37 municipal solid waste: Waste from homes, institutions, and commercial sources consisting of everyday
38 items such as product packaging, grass clippings, furniture, clothing, bottles and cans, food scraps,
39 newspapers, appliances, consumer electronics, and batteries. (Excluded from this category are municipal
40 wastewater treatment sludges, industrial process wastes, automobile bodies, combustion ash, and
41 construction and demolition debris.)
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1 N
2 National Ambient Air Quality Standards (NAAQS): Standards established by EPA that apply to
3 outdoor air throughout the country. The Clean Air Act established two types of national air quality
4 standards. Primary standards set limits to protect public health, including the health of "sensitive"
5 populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public
6 welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and
7 buildings. EPA has set NAAQS for the six criteria pollutants.
8 national indicator: An ROE indicator for which nationally consistent data are available, and which helps
9 to answer an ROE question at a national scale. Some national indicators also present data broken down by
10 EPA Region. See ROE indicator.
11 National Priorities List (NPL): EPA's list of the most serious uncontrolled or abandoned hazardous
12 waste sites identified for possible long-term remedial action under Superfund. See Superfund.
13 natural source: A term used in this report to describe any air emissions source of natural origin.
14 Examples include volcanoes, wild fires, wind-blown dust, and releases due to biological processes (see
15 biogenic source.
16 non-indigenous species: A species that has been introduced by human action, either intentionally or by
17 accident, into an area outside its natural geographical range; also called an alien, exotic, introduced, or
18 non-native species. Certain non-indigenous species are considered "invasive." (See invasive species.)
19 non-production-related waste: Waste that is not production-related; for example, waste associated with
20 catastrophic events and cleanup actions. Toxic chemicals in non-production-related waste must be
21 reported to the Toxics Release Inventory (see Toxics Release Inventory).
22 non-transient non-community water system: A type of public water system that supplies water to 25 or
23 more of the same people at least six months per year in places other than their residences. Some examples
24 are schools, factories, office buildings, and hospitals that have their own water systems. (See public water
25 system.)
26 nonpoint source: A diffuse source of pollution, having no single point of origin. This term is commonly
27 used to describe water pollution caused by rainfall or snowmelt moving over and through the ground and
28 carrying natural and human-made contaminants into lakes, rivers, streams, wetlands, estuaries, other
29 coastal waters, and ground water. Atmospheric deposition and hydrologic modification are also sources of
30 nonpoint water pollution.
31 non-public water system: A water system that does not provide water for human consumption through at
32 least 15 service connections, or regularly serve at least 25 individuals, for at least 60 days per year.
33 nutrient: Any substance assimilated by living things that promotes growth. The term is generally applied
34 to nitrogen and phosphorus but is also applied to other essential and trace elements.
35
36 O
37 oil and gas production waste: Gas and oil drilling muds, oil production brines, and other waste
38 associated with exploration for, or development and production of, crude oil or natural gas.
39 onsite treatment: See treatment.
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1 ozone-depleting substance: Any compound that contributes to stratospheric ozone depletion (see ozone
2 depletion).
3 ozone depletion: Destruction of the stratospheric ozone layer, which shields the earth from ultraviolet
4 radiation harmful to life. This destruction of ozone is caused by the breakdown of certain chlorine- and/or
5 bromine-containing compounds (chlorofluorocarbons or halons). These compounds break down when
6 they reach the stratosphere and then catalytically destroy ozone molecules.
9 point source: A fixed location or facility that discharges pollution—for example, a factory smokestack, a
10 ship, an ore pit, a ditch, or a pipe discharging treated industrial wastewater or treated sewage into a
11 waterway.
12 pollutant: Any substance introduced into the environment that may adversely affect the usefulness of a
13 resource or the health of humans, animals, or ecosystems. For most environmental media, this term is
14 commonly understood to refer to substances introduced by human activities. In the case of air, the
15 convention is to include substances emitted from natural sources as well (see air pollutant).
16 population: In ecology, a group of interbreeding organisms occupying a particular space. In other
17 contexts, including human health, this term generally refers to the number of humans living in a
18 designated area.
19 precursor: In photochemistry, any compound antecedent to a pollutant. For example, volatile organic
20 compounds and nitrogen oxides react in sunlight to form ozone or other photochemical oxidants. As such,
21 VOCs and nitrogen oxides are precursors.
22 primary pollutant: Any pollutant that is emitted into the atmosphere directly from its source and that
23 retains the same chemical form. An example of a primary pollutant is dust that blows into the air from a
24 landfill.
25 Priority Chemicals: A set of chemicals, found in the nation's products and wastes, that EPA targets for
26 voluntary reduction (or recovery and recycling if they cannot be eliminated or reduced at the source). The
27 list of Priority Chemicals is available at http://www.epa.gov/epaoswer/hazwaste/minimize/chemlist.htm.
28 production-related waste: The sum of a facility's production-related onsite waste releases, onsite waste
29 management (recycling, treatment, and combustion for energy recovery), and offsite transfers for
30 disposal, treatment, recycling, or energy recovery. Toxic chemicals in production-related waste must be
31 reported to the Toxics Release Inventory (see Toxics Release Inventory).
32 public water system: A system that provides water for human consumption through at least 15 service
33 connections, or regularly serves at least 25 individuals, for at least 60 days per year. Public water systems
34 are divided into three categories (see community water system, non-transient non-community water
35 system, and transient non-community water system). Examples of public water systems include municipal
36 water companies, homeowner associations, schools, businesses, campgrounds, and shopping malls.
37
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2 radioactive waste: Waste containing substances that emit ionizing radiation. Radioactive waste is
3 classified by regulation according to its source and/or content. The types of waste that are typically
4 considered "radioactive waste" include high-level waste, low-level waste, mixed low-level waste,
5 transuranic waste (i.e., elements heavier than uranium), and certain wastes from the extraction and
6 processing of uranium or thorium ore. Spent nuclear fuel, which is produced as a result of the controlled
7 nuclear fission process in nuclear reactors, is considered a nuclear material rather than radioactive waste.
8 RCRA Cleanup Baseline: A priority subset of the universe of facilities that are subject to cleanup under
9 the Resource Conservation and Recovery Act (RCRA) due to past or current treatment, storage, or
10 disposal of hazardous wastes, and that have historical releases of contamination.
11 RCRA hazardous waste: A national regulatory designation for certain wastes under the Resource
12 Conservation and Recovery Act (RCRA). Some wastes are given this designation because they are
13 specifically listed on one of four RCRA hazardous waste lists (see
14 http://www.epa.gov/epaoswer/osw/hazwaste.htm). Other wastes receive this designation because they
15 exhibit at least one of four characteristics—ignitability, corrosivity, reactivity, or toxicity.
16 regional indicator: An ROE indicator that helps to answer an ROE question on a smaller-than-national
17 geographic scale. A regional indicator may cover a topic for which nationally consistent data are
18 unavailable, or it may present an issue that is of particular concern within a certain geographic area. See
19 ROE indicator.
20 risk factor: A characteristic (e.g., race, sex, age, obesity) or variable (e.g., smoking, occupational
21 exposure level) associated with increased probability of an adverse effect.
22 ROE indicator: An indicator that meets the ROE criteria (see Box 1-1, p. 1-7) and has been peer-
23 reviewed. See indicator.
24
25 S
26 secondary pollutant: Any pollutant that is formed by atmospheric reactions of precursor or primary
27 emissions. Secondary pollutants undergo chemical or physical changes once they reach the atmosphere.
28 An example of a secondary pollutant is ground-level ozone, which forms from chemical reactions
29 involving airborne nitrogen oxides, airborne volatile organic compounds, and sunlight
30 sewage sludge: A semi-solid residue from any of a number of air or water treatment processes. When
31 treated and processed, sewage sludge becomes a nutrient-rich organic material called biosolids.
32 stratosphere: The layer of the atmosphere that starts about 6 to 9 miles above the Earth's surface at mid-
33 latitudes and lies atop the troposphere. The stratosphere contains small amounts of gaseous ozone, which
34 filters out about 99 percent of the incoming ultraviolet radiation.
35 stressor: A physical, chemical, or biological entity that can induce adverse effects on ecosystems or
36 human health.
37 Superfund: A program, operated under the legislative authority of the Comprehensive Environmental
38 Response, Compensation, and Liability Act and the Superfund Amendments and Reauthorization Act,
39 that funds and carries out EPA solid waste emergency and long-term removal and remedial activities.
40 These activities include establishing the National Priorities List, investigating sites for inclusion on the
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1 list, determining their priority, and conducting and/or supervising cleanup and other remedial actions. See
2 National Priorities List.
5 toxic chemical: A chemical that can produce injury if inhaled, swallowed, or absorbed through the skin.
6 Toxics Release Inventory (TRI): A database containing detailed information on nearly 650 chemicals
7 and chemical categories that over 23,000 industrial and other facilities manage through disposal or other
8 releases, recycling, energy recovery, or treatment.
9 Toxics Release Inventory (TRI) chemicals: The chemicals and chemical categories that appear on the
10 current TRI toxic chemical list. As of March 2006, the TRI toxic chemical list contains 581 individually
11 listed chemicals and 30 chemical categories (including 3 delimited categories containing 58 chemicals).
12 The list of TRI chemicals is available at http://www.epa.gov/tri/chemical/index.htm.
13 Toxics Release Inventory (TRI) facilities: The facilities that are required by Section 313 of the
14 Emergency Planning and Community Right to Know Act to report to the TRI. In the 2003 reporting year,
15 23,811 facilities reported to the TRI.
16 transient non-community water system: A type of public water system that provides water in a place—
17 such as a gas station or campground—where people do not remain for long periods of time. These
18 systems do not have to test or treat their water for contaminants that pose long-term health risks, because
19 fewer than 25 people drink the water over a long period. They still must test their water for microbes and
20 several chemicals. (See public water system)
21 treatment: Any process that changes the physical, chemical, or biological character of a waste to make it
22 less of an environmental threat. Treatment can neutralize the waste, recover energy or material resources
23 from it, render it less hazardous, or make it safer to transport, store, or dispose of.
24 Treatment Technique (TT): A required process intended to reduce the level of a contaminant in
25 drinking water.
26 troposphere: The layer of the atmosphere closest to the Earth's surface. The troposphere extends from
27 the surface up to about 6 to 9 miles.
28
29 U
30 underground injection: The technology of placing fluids underground in porous formations of rocks,
31 through wells or other conveyance systems. The fluids may be water, wastewater, or water mixed with
32 chemicals. Regulations for disposing of waste this way vary depending on type of waste. RCRA
33 hazardous waste is placed in highly regulated (Class 1) wells.
34 urbanization: The concentration of development in relatively small areas (cities and suburbs). The U.S.
35 Census Bureau defines "urban" as referring to areas with more than 1.5 people per acre.
36
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1 W
2 wadeable stream: A stream, creek, or small river that is shallow enough to be sampled using methods
3 that involve wading into the water. Wadeable streams typically include waters classified as first through
4 fourth order in the Strahler Stream Order classification system (Strahler, 1952).
5 wetland: An area that is inundated or saturated by surface or ground water at a frequency and duration
6 sufficient to support, and that under normal circumstances does support, a prevalence of vegetation
7 typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs,
8 and similar areas.
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i APPENDIX B:
2 DEVELOPMENT OF EPA's 2007 ROE: SCIENCE REPORT
3
4 EPA's 2007 Report on the Environment: Science Report (2007 ROE SR) was developed by the U.S.
5 Environmental Protection Agency (EPA). EPA's Office of Research and Development (ORD) led this
6 collaborative project, which involved EPA's program and Regional offices as well as external partners.
7 This appendix describes the key elements of the 2007 ROE development process.
8
9 Section 1.01 Laying the Foundation
10
11 EPA published its Draft Report on the Environment (2003 Draft ROE) in June 2003 and invited feedback.
12 The Agency received comments from several sources:
13
14 • The Science Advisory Board (SAB) reviewed the 2003 Draft ROE Technical Document in
15 March 2004, issuing draft comments shortly afterwards and publishing final comments in
16 December 2004 (SAB, 2004).
17
18 • Through February 2004, the public provided comments on the 2003 Draft ROE Technical
19 Document via EPA's on-line public comment system (EPA, 2004a).
20
21 • Stakeholders commented on the 2003 Draft ROE Public Report during six dialogue sessions
22 across the nation in 2003 and early 2004 (EPA, 2004b).
23
24 In January 2004, the EPA Administrator requested that work begin to develop the next version of the
25 Report on the Environment. Exhibit B-l shows the organizational structure for development of EPA's
26 2007 ROE: Science Report1. A standing ROE Work Group took the lead in all phases of development.
27 The group included five theme leads, each responsible for development for a particular chapter of the
28 2007 ROE, plus representatives of EPA Regions and other relevant EPA offices. During the development
29 process, the theme leads coordinated with other federal agencies and organizations involved in indicator
30 development or data collection. An Environmental Indicators Steering Committee, comprised of senior
31 managers from across the Agency, oversaw development of the Science Report. The Steering Committee
32 reviewed work group activities and draft products.
33
34 The ROE Science Report is based on three fundamental components:
35
36 • (1) A series of fundamental questions about the condition of the environment and its impact
37 on human health that the Agency considers to be most important and relevant to its mission.
38
39 • (2) An indicator definition.
40
41 • (3) Criteria against which indicators are evaluated in terms of how they answer the questions.
1 An additional organizational element, the Indicators Work Group, was added to the process as the indicators were
being finalized for the July 2005 peer review. The Indicators Work Group provided coordination between the ROE
Work Group and the Steering Committee.
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Exhibit B-1. Organizational structure for development of the 2007 ROE Science Report
Environmental Indicators
Steering Committee
Other federal agencies
and organizations
involved in indicator or
data development
I
ROE Work Group
Chapter Leads
•Office of Research and
Development
• Office of Air and Radiation
•Office of Water
• Office of Solid Waste and
Emergency Response
Other Participants
• Office of Prevention, Pesticides
and Toxic Substances
• EPA Regions
• Office of Policy, Economics
and Innovation
• Office of the Chief Financial
Officer
• Office of Environmental
Information
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
The first step in developing the 2007 Report on the Environment was to review and refine the 2003 Draft
ROE version of these components:
• Questions: Over 100 EPA specialists from across the Agency were convened in the five
ROE theme areas: air, water, land, human health, and ecological condition. Each theme team was
charged with considering feedback and refining the ROE questions. The questions were finalized
after review by the Environmental Indicators Steering Committee.
• Indicator definition and criteria: The 2003 Draft ROE indicator definition and criteria
were refined for the 2007 ROE using an iterative process that included input from EPA specialists
and review by the Environmental Indicators Steering Committee. Care was taken to ensure that
the criteria were consistent with requirements of EPA's Information Quality Guidelines.
Section 1.02 Indicator Development
Once the questions, definition, and criteria were refined, the next step was to identify and develop
indicators to answer the questions:
• 2003 Draft ROE indicators were screened against the 2007 ROE indicator definition and
criteria. Many 2003 Draft ROE indicators were proposed for the 2007 ROE; some were
withdrawn.
• Ideas for new indicators were solicited from across EPA, other federal agencies, and
organizations. Newly proposed indicators were screened for their ability to meet the indicator
definition and criteria and for their value in answering the ROE questions.
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1
2 For indicators that passed screening, three components were developed:
^
3
4 • Text describing the indicator.
5 • A graphic or table displaying the indicator data.
6 • A metadata form that documents the data source and quality (see Box B-l).
7
8 The 2007 ROE development team worked with staff at other departments, agencies, and private
9 organizations that originally developed indicators or provided indicator data to ensure that indicator
10 graphics, data, and quality assurance information were up to date and accurate. Indicators were reviewed
11 by the Environmental Indicators Steering Committee.
12
13 Section 1.03 Indicator Peer Review and Public Comment
14
15 Once the full suite of proposed indicators was assembled, all indicators were independently peer reviewed
16 by nationally recognized experts to ensure that they were scientifically sound and properly documented,
17 met the indicator definition and criteria, and were useful for answering the questions posed in the ROE.
18 Two rounds of review were conducted:
19
20 • At a workshop in July 2005, 21 experts reviewed the initial set of 88 proposed indicators.
21 • In November 2005, nine experts reviewed 11 indicators that were new or substantially
22 revised since the July review.
23
24 The peer review, organized by a contractor, was conducted following Office of Management and
25 Budget's (OMB's) specifications for peer review of "Highly Influential Scientific Assessments" as
26 specified in OMB's "Final Information Quality Bulletin for Peer Review" (OMB, 2004). The reviewer
27 selection criteria, list of reviewers, charge to reviewers, and reviewer comments can be found in the peer
28 review summary report (EPA, 2006). EPA announced the peer reviews in the Federal Register and also
29 posted the proposed indicators on a website for public comment. Key questions addressed during the
30 review are listed in Box B-2. After the peer review and public comment period, EPA revised and finalized
31 the indicators. EPA's responses to reviewer and public comments are available at [provide url].
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Box B-l. Questions Addressed in the 2007 ROE Metadata Forms
1 Are the physical, chemical, or biological measurements upon which this indicator is based widely accepted as
scientifically and technically valid?
1 Is the sampling design and/or monitoring plan used to collect the data over time and space based on sound
scientific principles?
1 Is the conceptual model used to transform these measurements into an indicator widely accepted as a
scientifically sound representation of the phenomenon it indicates?
1 To what extent is the indicator sampling design and monitoring plan appropriate for answering the relevant
question in the ROE?
1 To what extent does the sampling design represent sensitive populations or ecosystems?
1 Are there established reference points, thresholds or ranges of values for this indicator that unambiguously
reflect the state of the environment?
1 What documentation clearly and completely describes the underlying sampling and analytical procedures
used?
1 Is the complete data set accessible, including metadata, data-dictionaries and embedded definitions or are there
confidentiality issues that may limit accessibility to the complete data set?
1 Are the descriptions of the study or survey design clear, complete and sufficient to enable the study or survey
to be reproduced?
1 To what extent are the procedures for quality assurance and quality control of the data documented and
accessible?
1 Have appropriate statistical methods been used to generalize or portray data beyond the time or spatial
locations where measurements were made (e.g., statistical survey inference, no generalization is possible)?
1 Are uncertainty measurements or estimates available for the indicator and/or the underlying data set?
1 Do the uncertainty and variability impact the conclusions that can be inferred from the data and the utility of
the indicator?
1 Are there limitations, or gaps in the data that may mislead a user about fundamental trends in the indicator over
srace or time oeriod for which data are available?
1
2
3 Section 1.04 Science Report Review
4
5 Concurrent with indicator development, EPA's ROE team, working with specialists across the Agency,
6 developed the text elements of the 2007 ROE Science Report. The final indicators were incorporated into
7 the text to produce the full 2007 ROE Science Report. This document was reviewed three times:
8
9 • Internally at EPA
10 • Externally by other federal agencies and the Office of Management and Budget
11 • Externally by EPA's Science Advisory Board (includes public comment on the federal
12 docket)
13
14 EPA revised the document based on comments and, after the third review, finalized it for publication in
15 2007 [provide mi].
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Box B-2. Charge Questions for Peer Review of the Proposed 2007 ROE Indicators
• Indicate the extent to which you think the proposed indicator is appropriate, adequate, and useful for
evaluating [see footnote]?
• Indicate the extent to which you think the proposed indicator makes an important contribution to answering the
specific ROE question it is intended to answer.
• To what extent do you think the indicator meets the indicator definition?
• To what extent do you think the indicator meets each of the indicator criteria?
• Do you have any suggestions for more effective graphic presentation of the data?
• Provide any additional comments, suggestions, or concerns regarding the indicator that you have not already
noted earlier. In particular, note any limitations to the indicator.
• Select one: Overall, this indicator (1) should be included in the ROE07 SR; (2) should be included in
the ROE07 SR with the modifications identified above; or (3) should not be included in the ROE07 SR.
• Do any of the proposed indicators clearly seem to be more appropriate, adequate, or useful for evaluating [see
footnote] than others? Do any seem to be more important than the others for answering the question(s) they
are intended to answer?
• Are there any additional national-level indicators that make an important contribution to answering one of the
ROE questions in your topic area, but were not proposed for ROE07, that you would recommend? As you
consider this question, consider the list of indicators presented in ROE03 that EPA does not intend to carry
forward to ROE07, along with EPA's rationale for withdrawing them. If you disagree with EPA's rationale
and feel any of these indicators should be included in ROE07, please so indicate in your response to this
question, along with your rationale for why they should be included.
Footnote:
This part of the charge varied according to theme area as follows:
• Air: "...our nation's air and therefore useful for contributing to an overall picture of our nation's air"
• Water: "...our nation's waters and for contributing to an overall picture of our nation's waters"
• Chemicals on land: "...trends in chemicals used on land and their effects on human health and the
environment"
• Land wastes: "... trends in wastes and their effects on human health and the environment"
• Health: "...human health and for contributing to an overall picture of human health "
• Ecological Condition: "...ecological conditions and therefore useful for contributing to an overall picture
of ecological conditions "
1 Section 1.05
2 Section 1.06 References
o
4 EPA, 2006. Report of the Peer Review of Proposed ROE07 Indicators. Washington, DC: EPA Office of
5 Research and Development. Give website pdf location here
6
7 EPA, 2004a. E-docket for Draft Report on the Environmental Technical Document. Docket Number:
8 OEI-2003-0030. Through February 29, 2004. Available at:
9 httD://docket.epa.gov/edkpub/do/EDKStaffCollectionDetailView?obiectId=Ob0007d48016af48.
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1
2 EPA, 2004b. Summary Report of the National Dialogue on the EPA Draft Report on the Environment
3 2003. EPA Office of Environmental Information. Available at:
4 http://www.epa.gov/indicators/docs/National Dialogue Summary Report.pdf.
5
6 OMB, 2004. Final Information Quality Bulletin for Peer Review. December 16, 2004. Washington, DC:
7 Office of Management and Budget.
8
9 SAB, 2004. EPA's Draft Report on the Environment (ROE) 2003: An Advisory by the ROE Advisory
10 Panel of the EPA Science Advisory Board, EPA-SAB-05-004. Available at:
11 http://www.epa.gov/science l/fiscal05 .htm.
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Appendix C:
Comparison of Indicators Used in EPA's 2003 Draft ROE and
2007 ROE
- Indicators new to the 2007 report are listed in bold font
- Indicators in the 2003 report but withdrawn in 2007 are highlighted gray
- Explanation of indicators used in the 2003 Draft ROE but not in the 2007 ROE is provided at
the end of this appendix
AIR CHAPTER
OUTDOOR AIR QUALITY
2007 ROE Indicator Title
Particulate Matter Emissions
Sulfur Dioxide Emissions
Nitrogen Oxides Emissions
Volatile Organic Compounds Emissions
Lead Emissions
Air Toxics Emissions
Acid Deposition
Ambient Concentrations of Particulate Matter
Ambient Concentrations of Ozone
Ambient Concentrations of Lead
Ambient Concentrations of Benzene
Percent of Days with Air Quality Index Values
Greater Than 100
Ozone Levels over North America
Concentrations of Ozone-Depleting Substances
Regional Haze
Lake and Stream Acidity
Ozone Injury to Forest Plants
Carbon Monoxide Emissions
Mercury Emissions
Ambient Concentrations of Carbon Monoxide
Ambient Concentrations of Nitrogen Dioxide
Ambient Concentrations of Manganese
Compounds in EPA Region 5
Ozone and Particulate Matter Concentrations
for U.S. Counties in the U.S./Mexico Border
Region
Corresponding 2003 Draft ROE Indicator Title
Emissions: Particulate Matter (PM2 5 and PM10),
Sulfur Dioxide, Nitrogen Oxides, and Volatile
Organic Compounds
Emissions (utility): Sulfur Dioxide and Nitrogen
Oxides
Lead Emissions
Air Toxics Emissions
Deposition: Wet Sulfate and Wet Nitrogen
Atmospheric Deposition of Nitrogen (From the
Water Chapter)
Ambient Concentrations of Particulate Matter:
PM25and PM10
Ambient Concentrations of Ozone: 8-hour and 1-
hour
Ambient Concentrations of Lead
Ambient Concentrations of Selected Air Toxics
Number and Percentage of Days that Metropolitan
Statistical Areas (MSAs) have Air Quality Index
(AQI) Values Greater than 100
Ozone Levels Over North America
Concentrations of Ozone-Depleting Substances
(Effective Equivalent Chlorine)
Visibility
Acid Sensitivity in Lakes and Streams (From the
Water Chapter)
Ozone Injury to Trees (From the Eco Chapter)
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Withdrawn
Withdrawn
Worldwide and U.S. Production of Ozone-
Depleting Substances (ODSs)
Number of People Living in Areas with Air Quality
Levels Above the NAAQS for Particulate Matter
(PM) and Ozone
GREENHOUSE GASES
ROE 2007 Indicator Title
U.S. Greenhouse Gas Emissions
Atmospheric Concentrations of Greenhouse
Gases
Corresponding 2003 Draft ROE Indicator Title
INDOOR AIR QUALITY
ROE 2007 Indicator Title
U.S. Homes Above EPA's Radon Action Level
Blood Cotinine Level (From the Health Chapter)
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
U.S. Homes Above EPA's Radon Action Levels
Blood Cotinine Level
Blood Cotinine Level in Children (From the Health
Chapter)
Percentage of Homes Where Young Children are
Exposed to Environmental Tobacco Smoke
WATER CHAPTER
FRESH SURFACE WATERS
ROE 2007 Indicator Title
High and Low Stream Flows
Nitrogen and Phosphorus Discharge from Large
Rivers
Pesticides in Streams in Agricultural
Watersheds
Nitrogen and Phosphorus in Streams in
Agricultural Watersheds
Benthic Macroinvertebrates in Wadeable
Streams
Streambed Stability in Wadeable Streams
Nitrogen and Phosphorus in Wadeable
Streams
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Changing Stream Flows
Number/Duration of Dry Stream Flow Periods in
Grassland/Shrublands
Partly New Information and Part from Indicator:
Movement of Nitrogen (From the Eco Chapter)
Pesticides in Farmland Streams and Ground
Water
Nitrate in Farmland, Forested, and Urban Streams
and Ground Water (part replaced, part withdrawn)
Phosphorus in Farmland, Forested, and Urban
Streams (part replaced, part withdrawn)
Macroinvertebrate Biotic Integrity Index for
Streams
Altered Fresh Water Ecosystems
Lake Trophic State Index
Percent Urban Land Cover in Riparian Areas
Agricultural Lands in Riparian Areas
Sedimentation Index
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Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Phosphorus in Large Rivers
Atmospheric Deposition of Mercury
Chemical Contamination in Streams and Ground
Water
Toxic Releases to Water of Mercury, Dioxin, Lead,
PCBs, and PBTs
Sediment Contamination of Inland Waters
Fish Index of Biotic Integrity in Streams
GROUND WATER
ROE 2007 Indicator Title
Nitrate and Pesticides in Shallow Ground
Water in Agricultural Areas
Corresponding 2003 Draft ROE Indicator Title
Pesticides in Farmland Streams and Ground
Water
Nitrate in Farmland, Forested, and Urban Streams
and Ground Water (part replaced, part withdrawn)
WETLANDS
ROE 2007 Indicator Title
Wetland Extent, Change, and Sources of
Change
Corresponding 2003 Draft ROE Indicator Title
Wetland Extent and Change
Sources of Wetland Change/Loss
COASTAL WATERS
ROE 2007 Indicator Title
Trophic State of Coastal Waters
Coastal Benthic Communities
Coastal Sediment Quality
Submerged Aquatic Vegetation in the
Chesapeake Bay
Hypoxia in the Gulf of Mexico and Long
Island Sound
Harmful Algal Bloom Outbreaks Along the
Western Florida Coastline
Withdrawn
Corresponding 2003 Draft ROE Indicator
Title
Water Clarity in Coastal Waters
Dissolved Oxygen in Coastal Waters
Chlorophyll Concentrations
Total Nitrogen in Coastal Waters
Total Phosphorus in Coastal Waters
Benthic Community Index for Coastal Waters
Sediment Contamination of Coastal Waters
Sediment Toxicity in Estuaries
Total Organic Carbon in Sediments
Submerged Aquatic Vegetation (changed to
Regional indicator) (From the Eco Chapter)
a
Population Density in Coastal Areas
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DRINKING WATER
ROE 2007
Indicator Title
Population Served by Community Water
Systems with No Reported Violations of Health-
Based Standards
Corresponding 2003 Draft ROE Indicator Title
Population Served by Community Water Systems
that Meet all Health-Based Standards
RECREATION IN AND ON THE WATER
ROE 2007
Indicator Title
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Number of Beach Days that Beaches are Closed
or Under Advisory
CONSUMPTION OF FISH AND SHELLFISH
ROE 2007 Indicator Title
Contaminants in Lake Fish Tissue
Coastal Fish Tissue Contaminants
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Contaminants in Fresh Water Fish
Chemical Contamination (From the Eco Chapter)
(part withdrawn)
Percent of River Miles and Lake Acres Under Fish
Consumption Advisories
Number of Watersheds Exceeding Health-Based
National Water Quality Criteria for Mercury and
PCBs in Fish Tissue
LAND CHAPTER
LAND COVER
ROE 2007 Indicator Title
Land Cover
Land Cover in the Puget Sound/Georgia
Basin
Corresponding 2003 Draft ROE Indicator Title
Extent of Grasslands and Shrublands
Extent of forest area, ownership, and
management
Patches of Forest, Grassland, Shrubland, and
Wetland in Urban/Suburban Areas (From the Eco
Chapter)
Ecosystem Extent (From the Eco Chapter)
LAND USE
ROE 2007 Indicator Title
Land Use
Urbanization and Population Change
Corresponding 2003 Draft ROE Indicator Title
Extent of Urban and Suburban Lands
Extent of Agricultural Land Uses
Extent of Developed Lands (plus Land Chapter
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Withdrawn
Withdrawn
Intro from 2003 Draft ROE)
The Farmland Landscape
Sediment Runoff Potential from Croplands and
Pasturelands
CHEMICALS
ROE 2007 Indicator Title
Fertilizer Applied for Agricultural Purposes
Toxic Chemicals in Production-Related Wastes
Released, Treated, Recycled, or Recovered for
Energy Use
Pesticide Residues in Food
Reported Pesticide Incidents
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Fertilizer Use
Quantity and Type of Toxic Chemicals Released
and Managed
Toxic Releases to Water of Mercury, Dioxin, Lead,
PCBs, and PBTs
Pesticide Residues in Food
Agricultural Pesticide Use
Potential Pesticide Runoff from Farm Fields
Risk of Nitrogen Export
Risk of Phosphorus Export
Pesticide Leaching Potential (from the Eco
Chapter)
WASTE
ROE 2007 Indicator Title
Quantity of Municipal Solid Waste Generated
and Managed
Quantity of RCRA Hazardous Waste Generated
and Managed
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Quantity of Municipal Solid Waste (MSW)
Generated and Managed
Number and Location of Municipal Solid Waste
(MSW) Landfills (part replaced, part withdrawn)
Quantity of RCRA Hazardous Waste Generated
and Managed
Number and Location of RCRA Hazardous Waste
Management Facilities (part replaced, part
withdrawn)
Quantity of Radioactive Waste Generated and in
Inventory
Number and Location of Municipal Solid Waste
(MSW) Landfills
Number and Location of RCRA Hazardous Waste
Management Facilities
Number and Location of Superfund National
Priorities List (NPL) Sites
Number and Location of RCRA Corrective Action
Sites
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CONTAMINATED LANDS
ROE 2007 Indicator Title
High-Priority Cleanup Sites Where
Contaminated Ground Water Is Not
Continuing to Spread Above Levels of
Concern
High-Priority Cleanup Sites with No Human
Contact to Contamination in Excess of
Health-Based Standards
Corresponding 2003 Draft ROE Indicator Title
HUMAN HEALTH CHAPTER
HEALTH STATUS
ROE 2007 Indicator Title
Life Expectancy at Birth
Infant Mortality
General Mortality
Corresponding 2003
Draft ROE Indicator Title
Life Expectancy
Infant Mortality
DISEASE AND CONDITIONS
ROE 2007 Indicator Title
Cancer Incidence
Childhood Cancer Incidence
Cardiovascular Disease Prevalence and
Mortality
Asthma Prevalence
Chronic Obstructive Pulmonary Disease
Prevalence and Mortality
Low Birthweight
Birth Defects Rates and Mortality
Infectious Diseases Associated with
Environmental Exposures or Conditions
(with the following new additions: Giardiasis,
Lyme Disease, Rocky Mountain Spotted
Fever, West Nile Virus, Legionellosis)
Preterm Delivery
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Cancer Incidence
Childhood Cancer Incidence
Cardiovascular Disease Mortality
Cardiovascular Disease Prevalence
Asthma Prevalence
Childhood Asthma Prevalence
Chronic Obstructive Pulmonary Disease Mortality
Low Birthweight Incidence
Deaths Due to Birth Defects
Birth Defect Incidence
Cholera Prevalence
Cryptosporidiosis Prevalence
£. co/;O157:H7 Prevalence
Hepatitis A Prevalence
Salmonellosis Prevalence
Shigellosis Prevalence
Typhoid Fever Prevalence
Cancer Mortality
Asthma Mortality
Childhood Cancer Mortality
Childhood Asthma Mortality
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HUMAN EXPOSURE TO POLLUTANTS
ROE 2007 Indicator Title
Blood Lead Level
Blood Mercury Level
Blood Cadmium Level
Urinary Pesticide Level
Blood Persistent Organic Pollutants Level
Urinary Phthalate Level
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE
Indicator Title
Blood Lead Level
Blood Lead Level in Children
Blood Mercury Level
Blood Mercury Level in children
Blood Cadmium Level
Urine Organophosphate Levels to
Pesticides
Indicate
Urine Arsenic Level
Blood Volatile Organic Compound
Levels
ECOLOGICAL CONDITION CHAPTER
EXTENT AND DISTRIBUTION OF ECOLOGICAL SYSTEMS
ROE 2007 Indicator Title
Forest Extent and Type
Forest Fragmentation
Ecological Connectivity in EPA Region 4
Relative Ecological Condition of
Undeveloped Land in EPA Region 5
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Extent of Area by Forest Type
Forest Age Class
Forest Pattern and Fragmentation
Extent of Ponds, Lakes, and Reservoirs
Extent of Estuaries and Coastline
DIVERSITY AND BIOLOGICAL BALANCE
ROE 2007 Indicator Title
Fish Faunal Intactness
Bird Populations
Non-Indigenous Species in the Estuaries of
the Pacific Northwest
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
At-risk Native Forest Species
Populations of Representative Forest Species
Tree Condition
At-risk Native Grassland and Shrubland Species
Population Trends of Invasive and Native Non-
Invasive Bird Species
Non-native Fresh Water Species
At-risk Fresh Water Plant Communities
At-risk Native Fresh Water Species
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Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Coastal Living Habitats
Fish Diversity
At-risk Native Species
Bird Community Index
Shoreline Types
ECOLOGICAL PROCESSES
ROE 2007 Indicator Title
Carbon Storage in Forests
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Carbon Storage
Forest Disturbance: Fire, Insects, and Disease
CRITICAL PHYSICAL AND CHEMICAL ATTRIBUTES
ROE 2007 Indicator Title
U.S. and Global Mean Temperature and
Precipitation
Sea Level
Sea Surface Temperature
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE
Indicator Title
Soil Compaction
Soil Erosion (Forests)
Soil Erosion (Farmland)
Processes Beyond the Range of Historic Variation
Soil Quality Index
Terrestrial Plant Growth Index
EXPOSURE TO POLLUTANTS
ROE 2007 Indicator Title
Withdrawn
Withdrawn
Withdrawn
Corresponding 2003 Draft ROE Indicator Title
Animal Deaths and Deformities
Fish Abnormalities
Unusual Marine Mortalities
Explanation of indicators used in the 2003 Draft ROE but not in the 2007 ROE
A number of indicators were included in EPA's 2003 Draft ROE that are not included in the 2007 ROE.
The general reasons for these changes are described below, followed by indicator-specific explanations.
Members of the independent scientific review panel that reviewed the draft indicators for the 2007
ROE recommended their withdrawal.
EPA's Science Advisory Board Committee review of the 2003 Draft ROE recommended EPA
develop and utilize a more precise definition of "indicator" than was used for 2003 Draft ROE.
EPA developed a set of specific indicator criteria to provide a more precise conformance to Office
of Management and Budget (OMB) and EPA Information Quality Guidelines.
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The 2007 ROE introduced a Regional Pilot Project and developed and implemented a relevant
process. Sub-national or regional indicators that were included in 2003 Draft ROE but did not go
through this pilot are not included in the 2007 ROE.
When screened against these factors, a small number of the indicators in 2003 DRAFT ROE did not
conform to one or more of these requirements. Explanations for not including these indicators were peer
reviewed by an independent scientific panel along with the indicators in this report. Broadly speaking, the
explanations for withdrawal fall into four categories, coded as follows:
(D) Definition - The indicator fails to meet the improved indicator definition for the 2007 ROE.
(C) Criteria-The indicator fails to meet one of the six indicator criteria that were established to
conform to EPA Information Quality Guidelines.
(N) New indicator - The indicator is replaced by a "new" and superior indicator that was not
available for the 2003 Draft ROE.
(R) Regional - The indicator is not national in scope and is not part of the 2007 ROE Regional
Pilot Project.
(P) Peer Review - The independent peer review panel recommended withdrawing the indicator
from the 2007 ROE.
The following information briefly explains the rationale for withdrawing specific indicators from the 2007
ROE. Each indicator is categorized as D, C, N, R, or P. The indicators are organized by chapter.
Air Chapter
Worldwide and U.S. Production of Ozone-Depleting Substances (ODSs) - C
This 2003 Draft ROE indicator presented estimates of the amount of ODSs produced worldwide in 1986
and 1999, and annual U.S. production from 1958 to 1993. This indicator was withdrawn because of
issues concerning data reliability and relevance. Global ODC production data are not reliable with
respect to comparability among reporting countries. The US estimates are more reliable because of
legal reporting requirements and the small number of sources. However, the data set fails to account
for imports, and annual production is not a good surrogate for emissions of ODCs into the environment
because of the time between production and eventual entry into the environment is highly variable
among the various products and recovery systems.
Number of People Living in Areas with Air Quality Levels above the NAAQS for Particulate Matter
(PM) and Ozone - C
This 2003 Draft ROE indicator conveyed how many people (based on census) lived in counties where
air pollutant levels at times were above the level of the NAAQS during the year stated. It was intended
to give the reader some indication of the number of people potentially exposed to unhealthy air.
Because of changing populations and air quality standards, however, this indicator masks actual trends
in the levels of air pollutants. It is not a valid exposure indicator for the ROE because it is not based on
measurement of an actual marker of exposure measured on or in individuals.
Percentage of Homes Where Young Children are Exposed to Environmental Tobacco Smoke - D
This 2003 Draft ROE indicator portrayed the percentage of homes in the U.S. in which young children
were exposed to tobacco smoke in 1998 versus 1957. The survey is based on a questionnaire (do
children live in the home, and does someone who smokes regularly live in the home), rather than on
actual measurements of the amount of smoke actually present or the degree to which children are
exposed to the resulting smoke. This indicator violates the ROE indicator definition, requiring that
indicators be based on actual measurements, and the indicator "Blood Cotinine" provides a better
indicator of children's exposure to smoke.
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Water Chapter
Altered Fresh Water Ecosystems - C
Percent Urban Land Cover in Riparian Areas - C
Agricultural Lands in Riparian Areas - C
These 2003 Draft ROE indicators were based on the percentage of land within 30 m of the edge of a
stream or lake that is classified as urban or agriculture based on 1991 satellite data (NLCD). Baseline
data are incomplete, and there are no reference points for the appropriate percentage of such cover,
and it is not clear that the indicators could be reproduced with newer satellite data. There are no data
for other alterations such as damming, channelization, etc.
Lake Trophic State Index - R, C
This 2003 Draft ROE indicator was based on phosphorous data collected in a one-time a statistical
sample of lakes in the Northeast US during 1991-94. It is not included in the 2007 ROE Regional Pilot
Project.
Sedimentation Index - R, C
This 2003 Draft ROE indicator was based on data collected on freshwater streams in the Mid Atlantic
Highlands Region during a one-time 1993-94 statistical survey. It is not included in the 2007 ROE
Regional Pilot Project.
Phosphorus in Large Rivers - C
The indicator was based on phosphorus concentrations in large rivers sampled periodically by the
USGS National Stream Quality Accounting Network (NASQAN). Monitoring at many of the large river
NASQAN sites has been discontinued.
Atmospheric Deposition of Mercury - C
This indicator was withdrawn following peer review of the indicators because trend data could not be
analyzed in time to revise the indicator.
Chemical Contamination in Streams and Ground Water - C
This 2003 Draft ROE indicator was based on data from a large number of NAWQA watersheds. The
sampling and analytical protocols (including the analytes measured) are not comparable across all
NAWQA watersheds.
Sediment Contamination of Inland Waters - C
This 2003 Draft ROE indicator was based on reported concentrations of sediment contaminants
collected by a large number of organizations focusing particularly on places where sediment
contamination is perceived to be a problem (the EPA National Sediment Inventory). The database
suffers from a number of limitations: the data are heavily biased toward sites at which there is a known
or suspected toxicity problem and to particular geographic areas (non-representative of the nation), the
data cover different dates in different locations- making estimation of trends difficult, and the data and
procedures used to assign sites to a toxicity category are not uniform from watershed to watershed. It
is unsuitable for trend estimation.
Fish Index of Biotic Integrity in Streams - R, C
This 2003 Draft ROE indicator was based on fish community data collected on freshwater fish in the
Mid Atlantic Highlands Region during a one-time1993-96 statistical survey. Condition cannot be
assessed in streams where no fish were caught, because data were insufficient to indicate whether the
stream had poor quality or simply no fish. It is not included in the 2007 ROE Regional Pilot Project.
Population Density in Coastal Areas
Discussion of population density in coastal areas was moved to the introduction of the Water Chapter
section responding to the question, "What are the trends in extent and condition of coastal waters and
their effects on human health and the environment?"
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Number of Beach Days that Beaches are Closed or under Advisory - D
Percent of River Miles and Lake Acres under Fish Consumption Advisories - D
These 2003 Draft ROE indicators were based on the frequency of beach closures or fish consumption
advisories as reported to EPA voluntarily by states and local government organizations. The data are
not nationally or temporally consistent because of different and changing criteria for closing beaches or
issuing fish consumption advisories in the different states, many of which do not involve actual water
quality measurements. They are therefore administrative indicators (based on administrative action
rather than actual physical measurements) and fail to meet the definition for ROE indicators.
Number of Watersheds Exceeding Health-Based National Water Quality Criteria for Mercury and
PCBs in Fish Tissue - C
This 2003 Draft ROE indicator was based on voluntary reporting of Hg contamination using data that
has not undergone formal QA/QC review. It is not representative of the nation, or suitable for trend
monitoring.
Land Chapter
The Farmland Landscape - C
This 2003 Draft ROE indicator represented croplands and the forests orwoodlots, wetlands, grasslands
and shrublands, that surround or are intermingled with them, and the degree to which croplands
dominate the landscape http://www.heinzctr.orq/ecosystems/farm/lndscps.shtml. The indicator relies on
data generated using early 1990's satellite data, and it is unclear whether the definition of "farmland
landscape" is sufficiently precise to be replicated independently, especially with respect to any future
satellite data availability.
Sediment Runoff Potential from Croplands and Pasturelands - C
This 2003 Draft ROE indicator represented the estimated sediment runoff potential for croplands and
pasturelands based on topography, weather patterns, soil characteristics, and land-use land cover and
cropping patterns for the U.S. and the Universal Soil Loss equation www.brc.tamus.edu/swat. The
indicator addressed "potential" and not actual/current condition, and relied on a model to predict
ambient characteristics based on pressure/stressor measurements, which violates a fundamental ROE
protocol on the use of models in indicators. Trends in this indicator would likely be associated only with
trends in land cover, cropping practices, and weather (topography and soil type are unlikely to change).
No reliable spatial trend data at the appropriate scale exist for either cropping practices or land cover,
and consequently trends in this indicator would be difficult to calculate.
Agricultural Pesticide Use - C
Agricultural pesticide usage data, measured at the national aggregate level for all pesticides is very
difficult to interpret. From one time period to another the mix of pesticides changes, pest pressures
change, agricultural practices change, agricultural acreage changes, regulatory status of key uses
changes, and many other important variables change. Moreover, the effects of pesticide usage are
encountered at three levels of the product's life cycle: production, usage, and residues on foods. The
geographic distribution of those effects renders difficult the interpretation of national usage levels for all
pesticides, taken as a group. While it is of course possible to compare magnitudes of aggregates at
different times, the real significance for the environment is in the differences in the content and
geographic distribution of the aggregates, not in the magnitude of the aggregate.
Potential Pesticide Runoff from Farm Fields - C
Pesticide Leaching Potential - C
These 2003 Draft ROE indicators represented the potential movement of agricultural pesticides from
the site of application to ground and surface waters, based on estimates of pesticide leaching and
runoff losses derived from soil properties, field characteristics, management practices, pesticide
properties, and climate for 243 pesticides applied to 120 specific soils in growing 13 major agronomic
crops. The indicators address "potential" and not actual/current condition, and rely on models to predict
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ambient characteristics based on measurements of pressures/stressors, which violates a fundamental
ROE protocol on the use of models in indicators.
Risk of Nitrogen Export - C
Risk of Phosphorus Export - C
These 2003 Draft ROE indicators represented the potential movement of N and P from the site of
application to surface waters, based on a large empirical dataset relating land use to N and P observed
in receiving streams over several decades at a variety of locations. The indicators address "potential"
and not actual/current conditions, and rely on statistical models to predict ambient characteristics
based on measurements of pressures/stressors, which violates a fundamental ROE protocol on the use
of models in indicators.
Quantity of Radioactive Waste Generated and in Inventory - C
This 2003 Draft ROE indicator was based on production and inventory data collected by the
Department of Energy. Although the data continue to be collected, they are no longer publicly available
post-September 11, 2001; therefore ongoing data trends are not and will not be available for this
indicator in the future. Moreover, the earlier data reflected two distinct periods in the history of waste
generation in the nuclear weapons complex. The first reflected a period during which wastes and other
materials were being generated as an integral part of the production of weapons grade nuclear
materials and components. The period after 1989 reflected the cessation of large-scale production of
such materials and the initiation of clean-up activities and wastes from those initiatives. Thus, even
before the truncation of data in the post 9/11 period, there were significant issues with the comparability
of the data overtime.
Number and Location of Superfund National Priorities List (NPL) Sites - D
This 2003 Draft ROE indicator represented an administrative decision to force a cleanup, rather than an
amount of waste present or removed, and therefore does not meet the 2007 ROE indicator definition.
Number and Location of RCRA Corrective Action Sites - D
This 2003 Draft ROE indicator represents an administrative decision to force a cleanup, rather than an
amount of waste present or removed, and therefore does not meet the 2007 ROE indicator definition.
Human Health Chapter
Cancer Mortality - P
Childhood Cancer Mortality -P
Asthma Mortality - P
Childhood Asthma Mortality - P
The independent peer review panel recommended the removal of the cancer and asthma mortality
indicators because trends in these indicators are less likely to be due to changes in environmental
factors and are more likely a result of changes in social factors such as availability/access to
healthcare.
Urine Arsenic Level - R
This 2003 Draft ROE indicator was based on data from EPA Region 5 only, and is not part of the 2007
ROE Regional Pilot.
Blood Volatile Organic Compound Levels - C
This 2003 Draft ROE indicator was based on a convenience sample whose representativeness cannot
be determined or necessarily used as a baseline for future sampling. The indicator is based on detects
only, so there is no reference level. Also, VOCs are cleared from the bloodstream rapidly (~ 1hr), so
there is a significant possibility of false negatives, considering that exposures tends to be associated
with occupational and indoor settings.
Ecological Condition Chapter
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Extent of Ponds, Lakes, and Reservoirs - C
This 2003 Draft ROE indicator was based on data from the USGS National Wetlands Inventory. While
these data are based on a valid statistical sampling design, the total amount of surface water is less
than half of the area of lakes, reservoirs and ponds greater than 6 acres in size in the USGS National
Hydrography Data Set. Until this discrepancy is resolved, the indicator may not satisfy the ROE criteria.
Extent of Estuaries and Coastline - C
This 2003 Draft ROE indicator was based on remote sensing data, but is unlikely to show trends
unrelated to sea level rise and changing tides, so it is not a very useful indicator for trends.
At-risk Native Species - C
At-risk Native Grassland and Shrubland Species - C
At-risk Native Forest Species - C
Populations of Representative Forest Species - C
Non-native Fresh Water Species - C
At-risk Native Fresh Water Species - C
At-risk Fresh Water Plant Communities - C
The Ecological Condition chapter was restructured from the 2003 Draft ROE organization per the
recommendation of EPA's Science Advisory Board and numerous stakeholders. As such, the chapter
no longer requires that the above indicators be broken out by ecosystem. In addition, the ability to track
trends of many of these indicators is questionable.
Tree Condition - C
This 2003 Draft ROE indicator was based on an ongoing statistical sample of forests across the
contiguous US and comprises components that relate to crown (tree canopy condition), the ratio of
dead to live wood, and the fire class. This indicator likely relates more to forest management practices
than to environmental condition, and for this reason has low relevance value to EPA.
Population Trends of Invasive and Native Non-Invasive Bird Species - R
This 2003 Draft ROE indicator was based on an analysis of USGS Breeding Bird Survey data in
grassland and shrubland ecosystems for 5 year periods ranging from the late 1960s to 2000. Because
the ecological condition questions are no longer directed at specific ecosystems types, this appears to
be a regional indicator. Also, it is not clear at this time that the data for this indicator will be collected in
the future.
Coastal Living Habitats - C
This 2003 Draft ROE indicator was based on remote sensing data of coastal wetlands, mudflats, sea-
grass beds, etc., but the only system for which a national indicator has been developed is coastal
vegetated wetlands, which already is covered in another indicator.
Fish Diversity - R
This 2003 Draft ROE indicator was based on a statistical sample offish trawls in Mid-Atlantic estuaries
during 1997-98. This indicator is not part of the 2007 ROE Regional Pilot project, and EMAP is no
longer collecting fish samples to support this indicator.
Bird Community Index - R
This 2003 Draft ROE indicator was not national in scope or part of the ROE EPA Regional Pilot.
Shoreline Types - C
This 2003 Draft ROE indicator was based on NOAA's Environmental Sensitivity Index. The index is
based on a standardized mapping approach, but coverage is not complete for large parts of the
coastline and the data in some of the atlases are more than 15 years old. Consequently, this indicator
is not appropriate for measurement of representative, national trends.
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Forest Disturbance: Fire, Insects, and Disease - P
The independent peer review panel recommended that this indicator be withdrawn because it was
"limited in many aspects of its coverage: temporally, spatially, and in types of disturbance. . . Ecological
interpretation of disturbance patterns is difficult. . . For example, the lack of fire may actually represent
an ecological disturbance, while fire suppression can lead to overcrowded forests that are more
conducive to insect and disease outbreaks." The reviewers also commented that the data were
questionable and that the interdependence among the disturbance categories could result in significant
double-counting. Finally, timber harvest was not included even though it disturbs more acres than fires,
insects, or disease.
Soil Compaction - C
Soil Erosion - C
Forests - This 2003 Draft ROE indicator was based on an analysis of recent Forest Inventory and
Analysis data on climate events, fire frequency, and forest insect and disease outbreaks, which were
then compared to anecdotal data for the period 1800-1850. Because the early data are anecdotal, and
because the data mostly relate to forest management practices, etc., it is proposed that this indicator
has low relevance to EPA and that trend data are of questionable utility as an ROE indicator.
Farmland - This 2003 Draft ROE indicator presented an estimate of potential for erosion rather than
actual erosion measurements, and relied on a model to predict ambient characteristics based on
pressure/stressor measurements, which violates a fundamental ROE protocol on the use of models in
indicators.
Processes Beyond the Range of Historic Variation - C
This 2003 Draft ROE indicator was based on an analysis of recent Forest Inventory and Analysis data
on climate events, fire frequency, and forest insect and disease outbreaks, which were then compared
to anecdotal data for the period 1800-1850. Because the early data are anecdotal, and because the
data mostly relate to forest management practices, etc., it is proposed that this indicator has low
relevance to EPA and that trend data are of questionable utility as an ROE indicator.
Soil Quality Index - R
This 2003 Draft ROE indicator was based on a survey of soils in the Mid Atlantic region during the
1990s, and was neither repeated and is not part of the Regional Pilot Project for 2007 ROE.
Terrestrial Plant Growth Index - P
The independent peer review panel recommended that this indicator be withdrawn because "The
results are too ambiguous and not explained, or perhaps, unexplainable. . . NDVI is a crude measure of
growth. [Also] The relative deviation of the Plant Growth Index (20-40%) without explanation during the
period of analysis suggests that the indicator might lack the precision needed to assess national trends
in productivity."
Animal Deaths and Deformities - C
This 2003 Draft ROE indicator was based on data reported by a number of different organizations to
USGS on incidences of death or deformities in waterfowl, fish, amphibians, and mammals. Trends are
available only for waterfowl, and because data reporting is voluntary rather than systematic, the data
are not adequate to determine actual trends versus trends in reporting.
Fish Abnormalities - C
This 2003 Draft ROE indicator was based on a statistical sample offish trawls in estuaries in the
Atlantic and Gulf, but the data are no longer being collected by EMAP to support this indicator.
Unusual Marine Mortalities - C
This 2003 Draft ROE indicator was based on voluntary reporting of unusual mortality events to NOAA.
Because there is no systematic requirement to report, these data are not suitable to support national
trends in the indicator.
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Chemical Contamination - C
This 2003 Draft ROE indicator combined data from the USGS NAWQA program that are not consistent
in terms of sampling frequency or analytical protocols. The part of this indicator presenting contaminant
levels in coastal fish as measured by EPA's EMAP program was moved to a separate indicator in the
water chapter: "Coastal Fish Tissue Contaminants."
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