:PA/600/F-08/010 | www.epa.gov
United States
Environmental Protection
Agency
enter for Environmental Assessment
U.S. Environmental Protection Agency
Office of Research and Development
-------
National Center for Environmental Assessment
Who We Are & What We Do
www.epa.gov/ncea
EPA's National Center for Environmental Assessment (NCEA) is a leader in the science of human health and ecological risk as-
sessment, a process used to determine how pollutants or other stressors may impact human health and the environment.
NCEA occupies a critical position in EPA's Office of Research and Development (ORE)) between researchers in other parts of
ORE) and outside of EPA who are generating new findings and data and the regulators in EPA's Program Offices and Regions
who must make regulatory, enforcement, and remedial action decisions. NCEA prepares technical reports and assessments that
integrate and evaluate the most up-to-date research and serve as major elements of the science foundation supporting EPA poli-
cies. NCEA also conducts cutting-edge research to develop innovative quantitative risk assessment methods and tools that help
extrapolate between experimental data and real-world scenarios, improve our understanding of uncertainties, and facilitate care-
ful weighing of evidence.
NCEA's workforce is our strength—its scientists are recognized internationally for their expertise in toxicology, epidemiology,
biology, chemistry, and statistics. NCEA scientists serve on many federal government workgroups that are addressing critical
environmental challenges and questions.
Examples of NCEA's major efforts include:
• Conducting human health risk assessments and managing EPA's Integrated Risk Information System (IRIS)
(http://www.epa.gov/iris)
• Producing Integrated Science Assessments for reviews of the National Ambient Air Quality Standards
(NAAQS) (http://www.epa.gov/ncea/isa)
• Providing human health and ecological risk assessment research, methods, guidelines, training materials, and
technical support to EPA's Program Offices and Regions and the public (http://www.epa.gov/ncea/risk)
• Developing methods for integrating, deriving, and synthesizing cause and effect relationships for use in
impairment investigations and risk assessments (http://www.epa.gov/caddis)
• Providing scientific information and decision tools to resource managers, policy makers, and other stake-
holders in order to support them as they decide whether and how to respond to global climate change
(http://www.epa.gov/ncea/global.htm)
• Preparing EPA's Report on the Environment (http://www.epa.gov/ncea/roe)
For more information, see NCEA's Web site at http://www.epa.gov/ncea
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_1_rev6-09.indd
6/9/2009 2:22:52 PM
-------
www.epa.gov/ncea
Integrated Science Assessments
NCEA Ensures National Air Quality Standards
Consider Best and Most Recent Science
NCEA's Integrated Science Assessments
for the Six "Criteria" Air Pollutants
• Ground-level Ozone—AQCD final in 2006
• Lead—AQCD final in 2006
• Participate Matter—ISA-Criteria draft is currently
under review in 2009
• Carbon Monoxide—AQCD final in 2000,
Workshops for next review cycle started in 2008
• Nitrogen Dioxide—ISA-Health Criteria final in
July 2008 and ISA for Oxides of Nitrogen and
Sulfur - Environmental Criteria final in 2008
• Sulfur Dioxide—ISA-Health Criteria final in
September 2008 and ISA for Oxides of Nitrogen
and Sulfur - Environmental Criteria final in
2008
Clean air is an important goal in implementing EPA's
mission of protecting public health and the environ-
ment. NCEA supports this mission by creating the
scientific assessments that underlie development
of the National Ambient Air Quality Standards
(NAAQS). These ambient or outdoor air pollution
standards protect public health and the environment
from adverse effects caused by six principal air
pollutants, including ozone and paniculate matter.
known as the "criteria" air pollutants (see box). It
is essential for the standards to be based on the best
and most current scientific information. Scientists
worldwide are conducting research and publishing
their findings about the health and environmental
effects of air pollutants, with about 100 new articles
in the published literature each month. As findings
emerge, NCEA evaluates this new science and often
re-interprets the existing information base to prepare
the Integrated Science Assessments (ISAs), to provide
the scientific basis for EPA's decisions on retaining or
revising the air quality standards. This is an essential
part of executing the Clean Air Act (CAA) mandate
to "accurately reflect the latest scientific knowledge
useful in indicating the kind and extent of identifiable effects on public health and the environment which may be expected
from the presence of [a] pollutant in ambient air."
How Do Integrated Science Assessments Use the Latest Science?
NCEA scientists identify, evaluate, integrate, and assess the most up-to-date and policy-relevant science for the criteria air
pollutants, documenting their analyses in the ISAs, previously called Air Quality Criteria Documents. Through review of scien-
tific findings from atmospheric chemistry, physics, epidemiology, toxicology, ecology, and exposure research for the six criteria
pollutants, NCEA ensures that the basis for decisions on air quality standards reflect the best science available from all of these
disciplines. After conducting a literature review, which includes consideration of thousands of multidisciplinary publications.
NCEA identifies key information, performs new, focused analyses as needed, and integrates this scientific evidence to address
the most policy-relevant questions at EPA. NCEA's goal is to meet the Clean Air Act requirement for a 5-year review cycle
for each of the criteria pollutants. All ISAs are subjected to a rigorous and extensive peer review by the Clean Air Scientific
Advisory Committee, which consists of noted experts appointed by the EPA Administrator to comment on the technical quality
of the NAAQS reviews.
Using the Latest Exposure Science for ISAs
Because humans breathe a variable mixture of clean air and pollutants from many outdoor and indoor sources all day, it can
sometimes be difficult to separate pollutant sources and isolate specific effects. NCEA's research and state-of-the-science
assessments on ambient-level pollutant identification techniques and exposure processes have helped exposure scientists make
U.S. Environmental Protection Agency
Office of Research and Development
Insert_1_rev6-09.indd 3
6/9/2009 2:22:52 PM
-------
Integrated Science Assessments
better and more accurate estimates of what groups and individuals actually breathe. NCEA scientists then use these exposure
estimates to help epidemiologists interpret data on effects measured in studies conducted throughout the U.S. and the world.
These data are then used in analyses and assessments NCEA makes using the measurements of the actual concentrations of
outdoor pollutants along with an understanding of the uncertainties in these measurements to assess the strength of causality or
association between exposures and effects.
Using the Most Up-to-Date Epidemiology in ISAs
Human epidemiological studies provide the most compelling evidence for
the regulation of air pollutants because direct effects on human health can
be quantified. Careful integration and interpretation of results from a large
number of human studies, while considering the complexity of the informa-
tion they provide, is needed to assess public health risks. Epidemiological
studies can provide direct evidence for or against the need to revise or retain
a standard for a criteria air pollutant. During the NAAQS review process.
NCEA scientists consider the strengths and limitations, consistency, and
robustness of the available evidence to describe the health effects of criteria
pollutants, assess the concentrations at which health effects are observed, and
identify susceptible populations.
Recent science assessments in
which the NCEA review and integra
tion of the evidence from epidemio
logical studies was critical include:
• Air Quality Criteria for Ozone
and Related Photochemical
Oxidants (Final 2006)
• Air Quality Criteria for
Particulate Matter (Final 2004)
• Air Quality Criteria for Lead
(2006)
Interpretation of Clinical Studies in ISAs
The criteria air pollutants (see box above) for which the NAAQS are written
benefit from a long series of controlled human exposure studies where ozone, paniculate matter, or sulfur dioxide, for example.
are given to human subjects in controlled doses. This puts the criteria pollutants at a real advantage over some other environ-
mental pollutants because the interpretation and assessment of human health effects from real ambient exposures can be easier
with these controlled exposures, lessening the need for extrapolation from complex animal experiments, or control of possible
confounding elements. NCEA scientists evaluate these controlled human studies where they are available and have published
results of their reanalyses to better inform the scientific basis for decision-making on the standards.
Improved Understanding through Research and Information Management
In recognition of the tremendous importance of air quality to public health and the environment, EPA has implemented a
substantial research program related to air quality. This and other research programs produce research findings that are essential
to understand and integrate in the ISAs. To support effective assessments, NCEA has designed and is now implementing a
state-of-the-science information management system, the Health and Environmental Research Online (HERO) data base
system.
Scientific Integration to Inform Decisions
The great extent and diversity of information available on the criteria air pollutants presents a challenge to risk assessors. Of
key importance is to integrate information from clinical, human exposure, epidemiological and animal toxicology studies to
provide a coherent and comprehensive understanding of the nature and magnitude of human health effects posed by these
pollutants. NCEA has developed and applied a coherent framework to draw conclusions on causality (i.e., the nature and
likelihood of adverse effects to be caused by exposure) and to characterize the levels at which such effects may occur. This
comprehensive integration provides the internationally recognized fundamental scientific basis for establishing the national
ambient air quality standards.
For More Information
EPA's Air Quality Criteria Documents / Integrated Science Assessments Web site: http://www.epa.gov/ncea/isa
EPA's NAAQS Web site: http://www.epa.gov/ttn/naaqs/
Clean Air Research Program: http://www.epa.gov/ord/npd/cleanair-research-intro.htm
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_1_rev6-09.indd 4
6/9/2009 2:22:52 PM
-------
Report on the Environment
www.epa.gov/ncea
EPA's Report on the Environment:
Answering Key Questions about U.S. Health
and Environment
EPA's 2008 Report on the Environment (2008 ROE) compiles
the most reliable indicators currently available to answer 23
questions of critical importance to EPA's mission and the
nation's environment. The questions are divided into five
topics: air, water, land, human health, and ecological condi-
tion. The report presents 85 indicators— numerical values
derived from actual measurements of a stressor, 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.
With help and data from NOAA, USD A, Department of the
Interior, and other agencies and private sector collaborators,
NCEA scientists led a team from across EPA's Program and
Regional offices that developed the report, reviewed and
updated indicators from the 2003 Draft ROE, developed new
indicators, and screened them against the new 2008 ROE
indicator definition and criteria. Each indicator underwent
extensive external peer review and public comment before
being incorporated into the 2008 ROE. The report itself was
subjected to internal EPA and interagency review, followed
by independent peer review by EPA's Science Advisory
Board as well as public comment. Following final revisions,
EPA's 2008 ROE was released to the public on May 20, 2008.
NCEA also has been working across the Agency to improve
the utility of the ROE for Agency planning and decision-
making, and with colleagues from European and North
American environmental offices to improve environmental
reporting and to advance indicator science.
What Are the Findings in the Report on the
Environment?
The 2008 ROE compiles the most reliable indicators
incorporating the latest available data to help track critical
trends in the environment and human health. The report also
identifies key limitations of these indicators and gaps where
reliable indicators do not yet exist. These gaps and limitations
highlight the disparity between the current state of knowledge
and the goal of full, reliable, and insightful representation
of environmental conditions and trends, and they provide
direction for future research and monitoring efforts.
Examples of Key Questions Addressed in
EPA's 2008 Report on the Environment
What are the trends in outdoor air quality
and their effects on human health and
the environment?
What are the trends in extent and condition
of fresh waters and their effects on human
health and the environment?
What are the trends in land cover and
their effects on human health and the
environment?
What are the trends in health status in the
United States?
What are the trends in the extent and distri-
bution of the nation's ecological systems?
U.S. Environmental Protection Agency
Office of Research and Development
Insert_2_rev6-09.indd
6/9/2009 2:25:27 PM
-------
Report on the Environment
Examples of Indicators Presented in EPA's Report on the Environment
Air: emissions and ambient concentrations of carbon monoxide, lead, particulate matter, nitrogen
oxides, ozone, volatile organic compounds, green house gases, and acid deposition
Water: stream flows, nitrogen and phosphorus, pesticides in streams, wetland extent, hypoxia in the
Gulf of Mexico, fish tissue contaminants, and sediment quality
Land: land cover, forest extent and type, quantity of municipal and hazardous solid waste generated,
and fertilizer used for agriculture
Human Health: mortality, life expectancy at birth, infant mortality, cancer incidence, asthma prevalence,
birth defects, preterm delivery, blood levels for lead, mercury, cadmium, persistent organic pollutants,
and cotinine, and urinary levels of pesticides and phthalates
Ecological Condition: land cover, forest extent and type, urbanization and population change, coastal
benthic communities, birds, harmful algal bloom outbreaks, U.S. and global mean temperature, sea
surface temperature, and sea level
Examples of the findings in the 2008 ROE
include:
• Blood lead levels show a steady decline
since the 1980s.
• Continuing annual declines have been
seen in indicators of hazardous waste
generation and all air emissions indicators
with the exception of greenhouse gases.
• Moderate or high disturbances of bottom
invertebrate communities have been found
in approximately 1/3 of benthic coastal
communities and 2/3 of wadeable streams.
• Between 2002 and 2007, there has been a
45% decline in the number of high priority
clean-up sites with spreading goundwater
contamination.
Percent reduction in native fish species diversity in the contiguous U.S.
from historical levels to 1997-2003a
Percent of area
in each category
Data are displayed by 6-digit hydrologic unit code (HUQ watershed. Percent reduction is based on the
number of native species present during the period 1997-2003, compared with historical numbers
documented prior to 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: NatuieSeive, 2006
The map of the U.S., from the 2008 Report on the Environment shows the percent reduction in
native fish species diversity from 1970 to 1997-2003. These data are part of the Fish Faunal
Intactness Indicator in the Report on the Environment. Watershed covering about one-fifth
(21 percent) of the area of the contiguous U.S. appear to have fish faunas that are fully intact,
retaining the entire complement offish species that were present before 1970. Watersheds
covering nearly a quarter (24 percent) of the area have lost 10 percent or more of their native
fish species.
What Are Future Plans for
the Report on the Environment?
It is NCEA's goal to utilize the internet in
order to provide timely updates for indicators
and produce new editions of the ROE every 4 years and to time updates with the Agency's strategic planning process. New
editions will reflect revisions or additions to the key questions, updates and revisions of the indicators, and addition of new
indicators. An electronic version of the report, the e-ROE, has provided users with the ability to navigate and query the report
and additional content. It will be updated on an ongoing basis to keep the ROE content as current as possible.
For More Information
EPA Report on the Environment 2008 Home Page: http://www.epa.gov/ncea/roe
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_2_rev6-09.indd 2
6/9/2009 2:25:30 PM
-------
www.epa.gov/ncea
IRIS: An Influential and High Quality Source
of Health Effects Information for Chemical
Risk Assessment
When conducting human health risk assessments that
support decisions on air emissions, water discharges.
or contaminated site clean-ups, risk assessors need
high quality, peer reviewed information about human
health effects that may result from exposure to
chemical pollutants. More often than not, they use
the EPA's Integrated Risk Information System (IRIS).
a Web-based database of chemical assessments and
quantitative toxicity values that have been developed
by EPA and undergone rigorous peer reviews.
NCEA is responsible for preparing the IRIS
assessments, managing the peer review process, and
maintaining the online database. The main purpose of
IRIS is to meet EPA statutory, regulatory, or program
implementation needs, with special emphasis on
chemicals of high interest to the public or other
levels of government. Because of the high quality
of its assessments, IRIS is used widely beyond EPA.
including internationally.
What is IRIS' Role in Protecting
Human Health?
IRIS values are used in combination with site-specific
exposure information and, as such, play an essential
role in protecting human health. By incorporating
available scientific research findings into a compre-
hensive assessment, IRIS provides information that
risk assessors and managers can use to assess risk
and make decisions. Information in IRIS is a key part
of evaluating the potential for adverse health effects
from exposure to chemicals in the environment, and
IRIS assessments can have broad impact in the form
of regulatory—and other—decisions made by risk
managers. IRIS provides data for the human health
hazard identification and dose-response assessment
phases of chemical risk assessments and includes
information about cancer or non-cancer endpoints
depending on the availability and quality of toxico-
logical and epidemiological data. This information
can be used in combination with exposure information
to characterize the public health risks of a particular
substance in a given situation. Many environmental
stakeholders—EPA programs and regions, state and
local governments, federal and international agencies.
U.S. Environmental Protection Agency
Office of Research and Development
"The documents [produced for IRIS] are the gold
standard in risk assessments performed by program
offices, other federal agencies, states, and even
international organizations."
EPA Board of Scientific Counselors
ORD Human Health Risk Assessment Research Program Review
April 2008
mi
EPA's IRIS Web site receives over 20,000 hits a day
from readers in over 150 countries.
Health Effects Information Available on IRIS
Carcinogenicity information:
A cancer slope factor is a plausible upper bound,
approximating a 95% confidence limit, on the increased
cancer risk from lifetime exposure to an agent by
ingestion. This estimate, usually expressed in units of
proportion (of a population) affected per mg of substance/
kg body weight-day, is generally reserved for use in the
low-dose region of the dose-response relationship
An inhalation unit risk is a plausible upper-bound,
approximating a 95% confidence limit, on the increased
lifetime cancer risk estimated to result from continuous
exposure to an agent at a concentration of 1 ug/m^ in air.
Cancer assessments also include a qualitative weight-of-
evidence characterization which describes the likelihood
that a chemical may cause cancer in humans and the
conditions where carcinogenic effects might be expressed.
Non-cancer information:
A reference dose (RfD) is an estimate of a daily oral
exposure to the human population (including sensitive
subgroups) that is likely to be without an appreciable risk
of harmful effects over a lifetime.
A reference concentration (RfC) is an estimate of a
continuous inhalation exposure to the human population
(including sensitive subgroups) that is likely to be without
an appreciable risk of harmful effects during a lifetime.
EPA Board of Scientific Counselors
ORD Human Health Risk Assessment Research Program Review
April 2008
Insert_2_rev6-09.indd 3
6/9/2009 2:25:31 PM
-------
industry, and non-governmental organizations—use risk assessment to inform decisions to protect public health, such as
determining allowable levels of contaminants in drinking water.
The process for developing IRIS assessments is scientifically rigorous and collaborative, involving several rounds of scientific
review, lexicologists, biologists, health scientists, epidemiologists, and statisticians develop the assessments using available
scientific findings from the peer-reviewed literature. Biologically based mathematical models and data on mode of action
by which chemicals exert their toxic effects are used to answer questions about the human relevance of animal studies, to
extrapolate between animals and humans, to identify and assess sensitive subpopulations, and to select appropriate methods
to extrapolate from experimental doses to the generally low doses that people may encounter in their environments. Because
the assessments must reflect EPA's opinion, they undergo in-depth reviews by scientists throughout the Agency. The draft
assessments also receive review by scientists in other federal agencies and by highly-qualified independent external experts
whose scientific disciplines are appropriate for the chemical under review. On occasion, an assessment may be reviewed by
independent expert panels formed by the National Research Council of the National Academy of Sciences. The public also has
opportunities to comment on draft assessments and contribute data.
IRIS contains information on more than 540 chemicals. Each year, EPA publishes in the Federal Register a list of ongoing and
new assessments. NCEA solicits nominations for new and updated assessments from the public and within EPA. Assessments
are updated as new scientific information or methods evolve that could significantly change IRIS information.
Examples of IRIS Assessments
Benzene—widely used as an
industrial solvent, an intermediate in
chemical synthesis, and a component
of gasoline
Diesel engine exhaust—mix of gas
and particle pollutants emitted from
diesel engines
Boron and compounds—boric acid
and sodium salts of boron are used
for a variety of industrial purposes
and as fire retardants, laundry
additives, fertilizers, herbicides, and
insecticides
The assessment supported U.S. EPA's Office of Air and Radiation, Office
of Mobile Sources' Final Rule: Control of Hazardous Air Pollutants from
Mobile Sources (2007) which set new standards that establish controls on
gasoline, passenger vehicles, and gas cans to reduce emissions of benzene
and other mobile source air toxics.
NCEA's Health Assessment Document for Diesel Engine Exhaust has
informed EPA efforts to reduce pollution from diesel engines. A March
2008 rule set standards to reduce emissions from locomotive and marine
diesel engines by up to 90 percent. EPA also requires reductions in
pollution from new heavy-duty trucks and buses. Starting in 2006, diesel
fuel contains 97 percent less sulfur.
First IRIS assessment to use data-derived adjustment factors rather
than using default uncertainty factors. Uncertainty factors are used in
the derivation of non-cancer toxicity values that account for variation i
susceptibility among the human population, uncertainty in extrapolating
animal data to humans, and other uncertainties. Data-derived adjustment
factors provide better estimates of uncertainty compared to traditional
default uncertainty factors.
What Are Future Plans for IRIS?
EPA's NCEA will continue to update IRIS and add new assessments to ensure it continues as a trusted key resource for
chemical risk assessors. In addition, NCEA plans to update IRIS assessments that are more than 10 years old, when new studies
are available to support a revised toxicity value. NCEA will incorporate new assessment and modeling tools into IRIS as they
are adequately developed and peer reviewed.
For more information
Integrated Risk Information System (IRIS) Web site: http://www.epa.gov/iris
IRIS Hotline: http://www.epa.gov/iris/comments.htm
EPA's Risk Website: http://www.epa.gov/risk/
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_2_rev6-09.indd 4
6/9/2009 2:25:31 PM
-------
Global Change
NCEA's Global Change Research Program:
Assessing the Impacts of Climate Change
www.epa.gov/ncea
NCEA's Global Change Research Program provides critical information to improve society's ability to effectively respond to
the risks and opportunities presented by global change. The program addresses the potential consequences of global climate
change on air and water quality, aquatic ecosystems, human health, and socioeconomic systems in the United States. It also
generates decision-support tools for resource managers coping with a changing climate. These products are used by EPA.
communities, states, and others in adapting to climate variability and change.
The impacts of global change effects are often unique to a location such as a watershed or municipality. EPA's Global Change
Research Program emphasizes a place-based approach to respond to global change issues particular to a given area. As a
result, partnerships are established with locally-based decision makers to ensure that the program is responsive to their unique
scientific information needs and the socioeconomic realities at their locales. At the same time, NCEA scientists are working
to advance assessment science and develop more general approaches to adaptation that can be applied at multiple scales
and locations.
What Are NCEA's Major Contributions
to Global Change Research?
The Global Change Research Act of 1990, directs
agencies to "produce information readily usable
by policymakers attempting to formulate effective
strategies for preventing, mitigating, and adapting
to the effects of global change" and to undertake
periodic scientific assessments. The 13 Federal
agencies that make up the U.S. Climate Change
Science Program are developing a series of 21
synthesis and assessment products (SAPs) in
response to the mandate of the U.S. Climate Change
Science Program's Strategic Plan (2003). NCEA
scientists are lead authors for two of the SAPs.
The Global Change Research Program has three
major areas of emphasis: air quality, water quality/
aquatic ecosystems, and human health impacts from
global change. NCEA scientists are involved in
a multi-lab collaboration that assesses the conse-
quences of global change for U.S. air quality. NCEA
also evaluates the sensitivity to climate change of
water quality goals and the opportunities available
within the provisions of the Clean Water Act and
the Safe Drinking Water Act to address anticipated
impacts. For example, NCEA scientists are engaged
in assessments covering a range of aquatic ecosys-
tems and issues including coral reefs, watersheds.
estuaries, biocriteria and aquatic invasive species.
These efforts are done in collaboration with the
Office of Air and Radiation and the Office of Water.
NCEA Scientists Are Lead Authors on Synthesis
and Assessment Products (SAPs)
SAP 4.4: Preliminary Review of Adaptation Options
for Climate-sensitive Ecosystems and Resources
The report explains seven "adaptation approaches"
for six resource areas: national parks, national
forests, national wildlife refuges, wild and scenic
rivers, estuaries, and marine protected areas, which
can be used to maintain or increase the resilience
of ecological systems to climate change.
SAP 4.6: Analyses of the Effects of Global Change
on Human Health and Welfare and Human
Systems
The report focuses on impacts of global climate
change on three broad dimensions of the human
condition: human health, human settlements, and
human welfare. The report examines potential
impacts of climate change on human society,
opportunities for adaptation, and associated
recommendations for addressing data gaps and
near- and long-term research goals.
Health impacts that stem from climate change and associated changes in air and water quality also are evaluated by NCEA. For
example, NCEA participated in the Health Sector Assessment of the Global Change Research Program's Climate Change
U.S. Environmental Protection Agency
Office of Research and Development
Insert_3_rev6-09.indd
6/9/2009 2:44:18PM
-------
Impacts on the United States. As a result, NCEA scientists evaluated direct
heat effects with respect to mortality, morbidity, violence, and hospital
visits and climate impacts on aeroallergens.
In addition to assessments, NCEA develops interactive decision-support
tools that support informed discussion of climate variability and change.
For example, the Climate Assessment Tool provides users of EPA's
BASINS 4.0—a multi-purpose environmental analysis system that inte-
grates a geographical information system (GIS), national watershed data,
and modeling tools—the capability to examine climate sensitivities and
impacts. NCEA also is developing a set of GIS-based population and land
use projections. This project, Integrated Climate and Land Use Scenarios
(ICLUS) provides scientists and decision makers a national data base of
county-level population and land use changes through 2100 which are
designed to be consistent with the Intergovernmental Panel on Climate
Change's Special Report on Emission Scenarios. Combined with informa-
tion on changing climate and environmental conditions, these projections
allow users to assess future impacts of climate change.
What Are Future Plans for the Global Change
Research Program?
NCEA will continue to be actively involved in the Interagency Climate
Change Science Program. NCEA will also continue to advance assess-
ment science by developing innovative interactive tools for understanding
local scale systems and their sensitivities. The long-term goal of NCEA's
efforts is to provide the approaches, methods, and models to quantitatively
evaluate the effects of global change on air and water quality, associated
impacts on aquatic ecosystems and human health and adaptive responses to
ameliorate adverse consequences of these changes.
For More Information
NCEA's Global Change Program:
http://www.epa.gov/ncea/global.htm
EPA's Climate Change Program: http://www.epa.gov/climatechange/
EPA Global Change Research Program:
http://www.epa.gov/ord/npd/globalresearch-intro.htm
U.S. Climate Change Science Program:
http://www.usgcrp.gov/usgcrp/
NCEA's Global Change-Related
Water Quality and Aquatic
Ecosystems Reports
• A Screening Assessment of the
Potential Impacts of Climate
Change on Combined Sewer
Overflow (CSO) Mitigation in the
Great Lakes and New England
Regions
• Climate and Land Use Change
Effects on Ecological Resources
in Three Watersheds: A
Synthesis Report
• Climate Change Effects on
Stream and River Biological
Indicators: A Preliminary
Analysis
• Climate Change and Interacting
Stressors: Implications for Coral
Reef Management in American
Samoa
• Effects of Climate Change on
Aquatic Invasive Species and
Implications for Management
and Research
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_3_rev6-09.indd 2
6/9/2009 2:44:22 PM
-------
Risk Assessment Tools
www.epa.gov/ncea
NCEA Methods, Models, and Databases Provide
the Scientific Basis for Improved Health
and Ecological Risk Assessments
What types of human health problems are caused by
substances in the environment? How likely is it that
ecological resources, such as watersheds, will experi-
ence degradation when exposed to different amounts
of a pollutant? How severe is the potential harm likely
to be? These are examples of key questions addressed
in risk assessments conducted by scientists at the U.S.
EPA. Risk assessments provide decision makers with
the scientific information they need to make informed
decisions about actions that may be taken to protect
human health and the environment.
Scientists at NCEA conduct cutting edge research
to develop innovative and quantitative risk assess-
ment tools that combine knowledge about biology.
physiology, toxicology, ecology and statistics. They
are continually working to create and enhance
methods, models, and databases that inform EPA risk
assessments. State-of-the-art tools and data help risk
assessors extrapolate between experimental data and
real-world scenarios, characterize uncertainties, and
facilitate careful weighing of evidence.
NCEA's dose-response assessment tools help char-
acterize the risk of an adverse effect in humans at a
specified dose. Exposure assessment tools help deter-
mine the potential sources of a chemical, pathways
(e.g., inhalation vs. ingestion) leading to exposure.
and the magnitude and duration of contact with the
substance. Ecological risk assessment tools support
decision making to address ecological concerns such
as degradation of surface waters due to pollution. The guidance and tools highlighted here represent only a few of the entire
library that are available on NCEA's Web site, www.epa.gov/ncea.
Risk Assessment Methods
NCEA scientists are world leaders in developing and applying novel, state-of-the-art risk assessment methods. They are EPA
leaders in methods development, chairing and participating in many cross-agency workgroups. For example they have contrib-
uted significantly to framework documents that identify key issues to consider for different types of risk assessments (e.g..
for metals, for children) and ways to address those issues. They have also contributed to the development of risk assessment
guidelines that offer more specific procedural information (e.g., Guidelines for Carcinogen Risk Assessement, Guidelines for
Ecological Risk Assessment). While the guidances do not mandate exactly how assessments should be developed, they provide
EPA and other risk assessors with rigorously-vetted approaches that help improve the quality, consistency and use in decision
making of their assessments.
Dose-Response Modeling Highlights
Benchmark Dose (BMD) Modeling Software provides data-management tools and a user-friendly interface to support applica-
tion of different mathematical models to fit a dose-response dataset. This software is extremely important since it is used in all
of EPA's Integrated Risk Information System (IRIS) assessments, which provide the scientific basis for many regulatory and
public health decisions. The BMD approach can be used for both non-cancer and cancer dose-response assessments.
This graphic illustrates how the NOAEL is highly dependent
on sample size, and how the BMD approach addresses
this limitation. In this example, identical dose-response
data points from toxicology studies with different sample
sizes are shown. Figure 1 shows observed response and
statistical confidence limits for response levels in a study
that tested 10 animals at each dose level, and Figure 2
shows the same observations for 50 animals tested at each
dose level. The NOAEL derived from the study using fewer
animals is higher compared to the NOAEL from the study
with greater statistical confidence. The BMD approach
fits a curve to the data and estimates a response rate that
more appropriately reflects the uncertainty due to smaller
sample size.
U.S. Environmental Protection Agency
Office of Research and Development
Insert_3_rev6-09.indd 3
6/9/2009 2:44:23 PM
-------
It is more informative than the traditional approach of using a no observed adverse effect level (NOAEL) or lowest observed
adverse effect level (LOAEL) as the basis for dose-response assessment. In the BMD approach, the risk assessor fits a flexible
curve to the dose-response data and uses the results to select a dose level that is associated with a predetermined benchmark
response, such as a 10% increase in the incidence of a particular toxic effect. The BMD approach uses more information
provided in reports of lexicological studies, and provides more information to risk assessors, than the NOAEL/LOAEL
approach, and is preferred when suitable data sets are available. The NCEA BMD web-based modeling tools provide a signifi-
cant benefit to the international risk assessment community.
Physiologically based pharmacokinetic (PBPK) models use available measured physiological data to more accurately
characterize how the body absorbs, metabolizes, distributes, stores, and excretes a chemical and predict the internal dose of
the chemical at specific target organs. NCEA scientists published guidance for applying PBPK models in human health risk
assessments and quantifying the impact of age-related and other inter-individual differences that may affect health risk. This is
an innovative and cutting-edge approach that reduces uncertainty in risk assessments and is now used routinely in IRIS assess-
ments when suitable data are available.
Methods and Guidance for Assessing Chemical Mixtures
In real world scenarios, people are not exposed to one chemical at a time—rather, they experience myriad exposures on a daily
basis. To address this fact, NCEA has developed methods and guidance to evaluate exposure to mixtures from environmental
media such as drinking water, air and soil. NCEA scientists have conducted research and published methods that address these
real world exposure scenarios by quantifying chemical mixture exposures and estimating potential health risks resulting from
these exposures.
Exposure Assessment Tools
The Exposure Factors Handbook is an important resource developed by NCEA that provides key information for nearly
all exposure assessments conducted by EPA. It contains statistical data on factors such as drinking water consumption, soil
ingestion, inhalation rates, dermal factors including skin area and soil adherence factors, consumption of fruits and vegetables.
fish, meats, dairy products, homegrown foods, breast milk intake, human activity factors, consumer product use, and residential
characteristics. This information is used in risk assessments to calculate human exposure to contaminants. Values are recom-
mended for the general population and for various segments of the population who may have characteristics different from
the general population. The Child-Specific Exposure Factors Handbook consolidates child specific data into one resource, and
the Example Exposure Scenarios Tool provides outlines of scenarios to demonstrate how to best use the data in the Exposure
Factors Handbook. NCEA released a revised and expanded version of the Child-Specific Exposure Factors Handbook in
September 2008 and a revised and expanded version of the Exposure Factors Handbook will be available in draft form in 2009.
Ecological Risk Assessment Tools
Two cutting-edge ecological tools include the Causal Analysis/Diagnosis Decision Information System (CADDIS) and the
Integrated Climate and Land Use Scenarios (ICLUS). CADDIS allows watershed managers to determine what has caused
impairment in a water body with a web-based suite of resources. ICLUS provides scientists with a means to assess future
impacts of climate change on different land use scenarios. For more information on CADDIS and ICLUS please see the fact
sheets entitled CADDIS and NCEA's Global Change Research Program.
For More Information
EPA NCEA Human Health Guidelines Web Page: http://www.epa.gov/ncea/healthrisk.htm
EPA NCEA Ecological Guidelines Web Page: http://www.epa.gov/ncea/ecorisk.htm
EPA's Benchmark Dose Software (BMDS) Web Page: http://www.epa.gov/ncea/bmds
EPA NCEA Human Health Risk Tools Web Page: http://www.epa.gov/ncea/risktools.htm
EPA NCEA Chemical Mixtures Risk Assessment Guidance Web Page:
http://www.epa.gov/ncea/chem
EPA NCEA Physiologically Based Pharmacokinetic (PBPK) Web Page: http://www.epa.gov/ncea/pbpk
EPA Exposure Factors Handbook Web Page: http://www.epa.gov/ncea/efh
EPA Child-Specific Exposure Factors Handbook Web Page: http://www.epa.gov/ncea/child
U.S. Environmental Protection Agency 6/09
Office of Research and Development
Insert_3_rev6-09.indd 4 6/9/2009 2:44:23 PM
-------
Causal Analysis/Diagnosis Decision Information System
CADDIS: A Tool to Help Scientists Identify
Causes of Deradation of Streams and Rivers
www.epa.gov/ncea
Watershed management scientists turn into environmental detectives when streams, rivers, or wetlands become so impacted
by human activities that there are observable effects on plant and animal life. The scientists need to determine what stressor
or stressors are causing harmful effects so that effective solutions can be developed and implemented. To unravel these envi-
ronmental mysteries, NCEA, working with colleagues from the Agency's Office of Water (OW), Regional offices, and other
ORD laboratories created the Causal Analysis/Diagnosis Decision Information System (CADDIS), an online resource that
helps scientists find, access, organize, use, and share information to determine what has negatively affected the ecology of the
water body.
CADDIS is built upon EPA's Stressor Identification process, which is a formal method for identifying causes of impairments
to aquatic ecosystems. The system includes a step-by-step guide to conducting a causal analysis, example worksheets, and
informative material on several commonly encountered candidate causes. CADDIS also has a conceptual model library
for common stressors, including phosphorus, a nutrient that can lead to harmful algal blooms and other effects when high
levels are discharged into aquatic systems. The system features advice on how to use specific data analysis methods and
manage data for a causal assessment, downloadable data analysis tools, and other information sources, such as databases of
stressor-response information.
In What Situations Would CADDIS Be
Helpful and How?
Observations that might prompt the use of
CADDIS include:
• kills of fish, invertebrates, plants, or other
wildlife or domestic animals
• anomalies in any life form, such as tumors.
lesions, parasites, or disease
• altered community structure, such as the absence.
reduction, or dominance of a particular species
or group
• loss of species or shifts in abundance
• response of indicators designed to monitor or
detect biological, community, or ecological
condition (e.g., Index of Biotic Integrity or
Invertebrate Community Index)
• changes in the reproductive cycle, population
structure, or genetic similarity
• alteration of ecosystem function, such as nutrient
cycles, respiration, and photosynthetic rates
• alteration of the aerial extent and pattern of
different ecosystems (e.g., shrinking wetlands
or change in the mosaic of open water, wet
meadows, sandbars, and riparian shrubs
and trees)
The name CADDIS
recognizes the caddis
fly's role as a frequently
used bioindicator for
detecting impacts of
aquatic pollutants.
Regarding the benefit of using CADDIS:
"...the Stressor Identification procedure provided a
clear, easily understandable format for us to explain
and support our conclusions. Our ability to present
the results of our analysis in a form that was under-
standable to both scientists and non-scientists.
I believe was critical to the ultimate adoption
and approval of the TMDL [Total Maximum Daily
Load—the maximum amount of a pollutant that a
water body can receive and still meet water quality
standards and an allocation of that amount to the
pollutants sources]."
Lee Dunbar,
Connecticut TMDUWQS program
U.S. Environmental Protection Agency
Office of Research and Development
Insert_4_rev6-09.indd
6/9/2009 2:54:59 PM
-------
Causal Analysis/Diagnosis Decision Information System
• CADDIS provides the following basic information on 8 common candidate
causes of biological impairment:
» what to consider (e.g., sources and site evidence) when deciding whether
to include stressors as candidate causes
» ways to measure stressors
» relevant literature reviews
» conceptual model diagrams showing linkages among stressors and their
potential sources and effects
CADDIS brings together significant amounts of information in an efficient and
effective way. It helps state and local water quality managers develop TMDLs
designed to address pollutants contributing to biological impairment in streams.
It assists watershed managers with planning and coordination of data collection.
best management practices, and technology solutions to address the causes and
sources of impairment.
EPA's Stressor Identification Framework Used in
CADDIS
Detect or Suspect Biological Impairment
Stressor Identification
Define the Case
Decision-maker
and
Stakeholder
Involvement
List Candidate Causes
Evaluate Data from the Case
As Necessary:
Acquire Data,
and
Iterate Process
Evaluate Data from Elsewhere
Identify Probable Cause
Identify and Apportion Sources
Management Action:
Eliminate or Control Sources, Monitor Results
Biological Condition Restored or Protected
Common Candidate Causes
of Biological Impairment
in Aquatic Ecosystems
Excess metals
Increased sedimentation
Excess nutrients
Low dissolved oxygen
High temperature
Altered ionic strength
Flow alteration
Unspecified toxic chemicals
What Are Future Plans for
CADDIS?
NCEA scientists plan to develop improved
versions of CADDIS based on user input
and feedback. These plans include adding
modules for deriving empirical stressor-
response relationships, stressor-specific
tolerance values and databases, syntheses of
relevant literature and statistical methods.
candidate cause summaries, and conceptual
models. NCEA also plans to add more case
studies, including those relevant to terrestrial
systems, with links to relevant CADDIS
pages and capabilities for user input.
For More Information
EPA's Causal Analysis/Diagnosis Decision
Information System (CADDIS) Web Page:
http://www.epa.gov/caddis
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_4_rev6-09.indd 2
6/9/2009 2:54:59 PM
-------
National Emergencies
NCEA Responds: Technical Assistance
for Emergency Response and Recovery
www.epa.gov/ncea
Environmental emergencies involve sudden increased threats to public health and the environment from the release or potential
release of hazardous materials due to accidents or natural or man-made disaster events. They happen without warning, and
the need for environmental assessment is acute. The environmental questions add to the anxiety and loss of the more obvious
physical damage. As soon as the dust begins to settle, many scientific questions need to be addressed quickly. How should
sampling be conducted to measure exposure levels quickly and accurately? How significant are the risks to public health (e.g.
first responders, clean-up personnel, residents) and the environment? Are proposed clean-up and recovery methods effective
and when is it safe for re-entry by the public?
Scientists in NCEA help respond to these questions by providing on-call technical support to emergency response and recovery
personnel in the EPA's Office of Solid Waste and Emergency Response and EPA regions who are primarily responsible for
coordinating EPA's emergency response programs.
Hurricanes Katrina and Rita
NCEA scientists and managers contributed to EPA's
environmental and human health impact assessment
of the aftermath of Hurricanes Katrina and Rita in the
Gulf Coast region in 2005. NCEA scientists partici-
pated in an interagency workgroup on guidance
and standards for local officials, and they provided
critical internal peer reviews of water and sediment
sampling and analysis plans and public communica-
tion materials. The ability of NCEA scientists to
respond quickly to internal EPA requests for scientific
expertise helped EPA and other Federal Agencies
make better decisions in these crisis situations.
Elevated Lead in Washington, DC
Drinking Water
In 2004 and 2005, the District of Columbia Water
and Sewer Authority detected high levels of lead
in numerous samples of residential drinking water.
NCEA scientists evaluated the potential impacts on
children's blood lead levels and analyzed risks for
a "highly exposed" subpopulation of infants who
consumed reconstituted formula prepared with tap
water. Results from the health assessment helped
inform response actions by local officials, such as
issuance of public health advisories, replacement of
many lead water pipes throughout the city, and corro-
sion control measures. The assessment results were
used by EPA's Office of Water and EPA Region 3 in
communicating risk to Washington, DC residents.
Due to control treatments that have been
House with Asbestos Cement Shingles
Water Contamination and Debris
Massive Debris Pile for Grinding and
Incinerations
Debris Grinder at Empire landfill in
Plaquemine parish
Clean up of debris from Hurricane Katrina generated
health concerns because debris from older buildings
may contain asbestos and lead. ORD scientists
developed a methodology to assess risks from the
release of these hazardous substances in trial testing
of grinding and burning (incineration) technologies
that potentially will be used to manage the debris.
U.S. Environmental Protection Agency
Office of Research and Development
Insert_4_rev6-09.indd 3
6/9/2009 2:55:02 PM
-------
National Emergencies
implemented, DC is now in compliance with safe drinking water act requirements, and risks to children from lead in drinking
water have been reduced.
Collapse of the World Trade Center
In the days following the attack on the World Trade Center towers on September
11, 2001, EPA initiated numerous air monitoring activities to better understand
the impact of emissions from that disaster. Using these data, NCEA scientists
conducted a screening of the potential for risk to the general population associ-
ated with off-site inhalation exposure of emissions in the aftermath of the attack.
This assessment did not address exposures and potential impacts that could have
occurred to rescue workers, firemen, and other site workers nor did it consider
indoor exposures. NCEA's work resulted in important analyses that could
improve EPA's responses to future national emergencies.
Asbestos Contamination in Libby, Montana
In 1999, an EPA Emergency Response Team went to Libby to investigate local
concerns about asbestos-contaminated vermiculite that is mined in the town.
Vermiculite is a mineral that, when heated, pops creating pockets of air that make
it suitable for use as insulation or as a soil amendment. The asbestos contamina-
tion in Libby is a distinct form of asbestos. Since 1999, EPA has been working
closely with the community to clean up contamination and reduce risks to human
health. EPA conducted a screening level risk assessment in 2001, and NCEA
scientists are currently working on a toxicity assessment specific to the unique
asbestos in Libby, Montana. This assessment will ensure EPA's site clean-up in
Libby, MT, is protective of human health. This work has broad scale implications
because 80 percent of the world's vermiculite was produced from the Libby mine
and the materials were processed in over 200 locations across the United States.
What Are Future Plans for Incidence Response?
NCEA scientists will continue to provide advice and scientific support to EPA
Program Offices, Regions, and the Emergency Response Program when envi-
ronmental crises arise. By building experience with real-world situations, NCEA
scientists are developing innovative approaches for exposure assessments and risk
assessments that will be applicable to natural and man-made disasters.
NCEA's Superfund Health Risk
Technical Support Center
This hotline resource is used
by EPA regional and program
office hazardous waste site
managers to obtain the latest
information on health risks
from toxic substances. There
are over 1,500 sites on
Superfund's National Priorities
List that require site assess
ment and clean-up. When
toxicity values are not avail
able in EPA's Integrated Risk
Information System (IRIS)
database, NCEA can provide
Superfund risk assessors with
provisional peer-reviewed
hotline responds to about 250
calls a year. All assistance
is provided on a rapid turn-
around basis.
For More Information
EPA Response to 2005 Hurricanes Web Page: http://www.epa.gov/katrina/
EPA NCEA World Trade Center Response Web Page:
http://www.epa.gov/ncea/wtc.htm
EPA Region 3 Lead in Drinking Water Web Page: http://www.epa.gov/dclead/
EPA Region 8 Libby Asbestos Web page:
http://www.epa.gov/region8//superfund/libby/index.html
Superfund Health Risk Technical Support Center (STSC) Hot Line: 513-569-7300
U.S. Environmental Protection Agency
Office of Research and Development
6/09
Insert_4_rev6-09.indd 4
6/9/2009 2:55:02 PM
-------
.
Recycled/Recyclable
Printed with vegetable based ink
on paper that containsamini mum
of 50%postconsumerfibercontent
processed chlorine free
------- |